text: /* vi:set ts=8 sts=4 sw=4:
   *
   * Handling of regular expressions: vim_regcomp(), vim_regexec(), vim_regsub()
   *
   * NOTICE:
   *
   * This is NOT the original regular expression code as written by Henry
   * Spencer.  This code has been modified specifically for use with the VIM
   * editor, and should not be used separately from Vim.  If you want a good
   * regular expression library, get the original code.  The copyright notice
   * that follows is from the original.
   *
   * END NOTICE
   *
   *	Copyright (c) 1986 by University of Toronto.
   *	Written by Henry Spencer.  Not derived from licensed software.
   *
   *	Permission is granted to anyone to use this software for any
   *	purpose on any computer system, and to redistribute it freely,
   *	subject to the following restrictions:
   *
   *	1. The author is not responsible for the consequences of use of
   *		this software, no matter how awful, even if they arise
   *		from defects in it.
   *
   *	2. The origin of this software must not be misrepresented, either
   *		by explicit claim or by omission.
   *
   *	3. Altered versions must be plainly marked as such, and must not
   *		be misrepresented as being the original software.
   *
   * Beware that some of this code is subtly aware of the way operator
   * precedence is structured in regular expressions.  Serious changes in
   * regular-expression syntax might require a total rethink.
   *
   * Changes have been made by Tony Andrews, Olaf 'Rhialto' Seibert, Robert
   * Webb, Ciaran McCreesh and Bram Moolenaar.
   * Named character class support added by Walter Briscoe (1998 Jul 01)
   */
  
  /* Uncomment the first if you do not want to see debugging logs or files
   * related to regular expressions, even when compiling with -DDEBUG.
   * Uncomment the second to get the regexp debugging. */
  /* #undef DEBUG */
  /* #define DEBUG */
  
  #include "vim.h"
  
  #ifdef DEBUG
  /* show/save debugging data when BT engine is used */
  # define BT_REGEXP_DUMP
  /* save the debugging data to a file instead of displaying it */
  # define BT_REGEXP_LOG
  # define BT_REGEXP_DEBUG_LOG
  # define BT_REGEXP_DEBUG_LOG_NAME	"bt_regexp_debug.log"
  #endif
  
  /*
   * The "internal use only" fields in regexp.h are present to pass info from
   * compile to execute that permits the execute phase to run lots faster on
   * simple cases.  They are:
   *
   * regstart	char that must begin a match; NUL if none obvious; Can be a
   *		multi-byte character.
   * reganch	is the match anchored (at beginning-of-line only)?
   * regmust	string (pointer into program) that match must include, or NULL
   * regmlen	length of regmust string
   * regflags	RF_ values or'ed together
   *
   * Regstart and reganch permit very fast decisions on suitable starting points
   * for a match, cutting down the work a lot.  Regmust permits fast rejection
   * of lines that cannot possibly match.  The regmust tests are costly enough
   * that vim_regcomp() supplies a regmust only if the r.e. contains something
   * potentially expensive (at present, the only such thing detected is * or +
   * at the start of the r.e., which can involve a lot of backup).  Regmlen is
   * supplied because the test in vim_regexec() needs it and vim_regcomp() is
   * computing it anyway.
   */
  
  /*
   * Structure for regexp "program".  This is essentially a linear encoding
   * of a nondeterministic finite-state machine (aka syntax charts or
   * "railroad normal form" in parsing technology).  Each node is an opcode
   * plus a "next" pointer, possibly plus an operand.  "Next" pointers of
   * all nodes except BRANCH and BRACES_COMPLEX implement concatenation; a "next"
   * pointer with a BRANCH on both ends of it is connecting two alternatives.
   * (Here we have one of the subtle syntax dependencies:	an individual BRANCH
   * (as opposed to a collection of them) is never concatenated with anything
   * because of operator precedence).  The "next" pointer of a BRACES_COMPLEX
   * node points to the node after the stuff to be repeated.
   * The operand of some types of node is a literal string; for others, it is a
   * node leading into a sub-FSM.  In particular, the operand of a BRANCH node
   * is the first node of the branch.
   * (NB this is *not* a tree structure: the tail of the branch connects to the
   * thing following the set of BRANCHes.)
   *
   * pattern	is coded like:
   *
   *			  +-----------------+
   *			  |		    V
   * <aa>\|<bb>	BRANCH <aa> BRANCH <bb> --> END
   *		     |	    ^	 |	    ^
   *		     +------+	 +----------+
   *
   *
   *		       +------------------+
   *		       V		  |
   * <aa>*	BRANCH BRANCH <aa> --> BACK BRANCH --> NOTHING --> END
   *		     |	    |		    ^			   ^
   *		     |	    +---------------+			   |
   *		     +---------------------------------------------+
   *
   *
   *		       +----------------------+
   *		       V		      |
   * <aa>\+	BRANCH <aa> --> BRANCH --> BACK  BRANCH --> NOTHING --> END
   *		     |		     |		 ^			^
   *		     |		     +-----------+			|
   *		     +--------------------------------------------------+
   *
   *
   *					+-------------------------+
   *					V			  |
   * <aa>\{}	BRANCH BRACE_LIMITS --> BRACE_COMPLEX <aa> --> BACK  END
   *		     |				    |		     ^
   *		     |				    +----------------+
   *		     +-----------------------------------------------+
   *
   *
   * <aa>\@!<bb>	BRANCH NOMATCH <aa> --> END  <bb> --> END
   *		     |	     |		      ^       ^
   *		     |	     +----------------+       |
   *		     +--------------------------------+
   *
   *						      +---------+
   *						      |		V
   * \z[abc]	BRANCH BRANCH  a  BRANCH  b  BRANCH  c	BRANCH	NOTHING --> END
   *		     |	    |	       |	  |	^		    ^
   *		     |	    |	       |	  +-----+		    |
   *		     |	    |	       +----------------+		    |
   *		     |	    +---------------------------+		    |
   *		     +------------------------------------------------------+
   *
   * They all start with a BRANCH for "\|" alternatives, even when there is only
   * one alternative.
   */
  
  /*
   * The opcodes are:
   */
  
  /* definition	number		   opnd?    meaning */
  #define END		0	/*	End of program or NOMATCH operand. */
  #define BOL		1	/*	Match "" at beginning of line. */
  #define EOL		2	/*	Match "" at end of line. */
  #define BRANCH		3	/* node Match this alternative, or the
  				 *	next... */
  #define BACK		4	/*	Match "", "next" ptr points backward. */
  #define EXACTLY		5	/* str	Match this string. */
  #define NOTHING		6	/*	Match empty string. */
  #define STAR		7	/* node Match this (simple) thing 0 or more
  				 *	times. */
  #define PLUS		8	/* node Match this (simple) thing 1 or more
  				 *	times. */
  #define MATCH		9	/* node match the operand zero-width */
  #define NOMATCH		10	/* node check for no match with operand */
  #define BEHIND		11	/* node look behind for a match with operand */
  #define NOBEHIND	12	/* node look behind for no match with operand */
  #define SUBPAT		13	/* node match the operand here */
  #define BRACE_SIMPLE	14	/* node Match this (simple) thing between m and
  				 *	n times (\{m,n\}). */
  #define BOW		15	/*	Match "" after [^a-zA-Z0-9_] */
  #define EOW		16	/*	Match "" at    [^a-zA-Z0-9_] */
  #define BRACE_LIMITS	17	/* nr nr  define the min & max for BRACE_SIMPLE
  				 *	and BRACE_COMPLEX. */
  #define NEWL		18	/*	Match line-break */
  #define BHPOS		19	/*	End position for BEHIND or NOBEHIND */
  
  
  /* character classes: 20-48 normal, 50-78 include a line-break */
  #define ADD_NL		30
  #define FIRST_NL	ANY + ADD_NL
  #define ANY		20	/*	Match any one character. */
  #define ANYOF		21	/* str	Match any character in this string. */
  #define ANYBUT		22	/* str	Match any character not in this
  				 *	string. */
  #define IDENT		23	/*	Match identifier char */
  #define SIDENT		24	/*	Match identifier char but no digit */
  #define KWORD		25	/*	Match keyword char */
  #define SKWORD		26	/*	Match word char but no digit */
  #define FNAME		27	/*	Match file name char */
  #define SFNAME		28	/*	Match file name char but no digit */
  #define PRINT		29	/*	Match printable char */
  #define SPRINT		30	/*	Match printable char but no digit */
  #define WHITE		31	/*	Match whitespace char */
  #define NWHITE		32	/*	Match non-whitespace char */
  #define DIGIT		33	/*	Match digit char */
  #define NDIGIT		34	/*	Match non-digit char */
  #define HEX		35	/*	Match hex char */
  #define NHEX		36	/*	Match non-hex char */
  #define OCTAL		37	/*	Match octal char */
  #define NOCTAL		38	/*	Match non-octal char */
  #define WORD		39	/*	Match word char */
  #define NWORD		40	/*	Match non-word char */
  #define HEAD		41	/*	Match head char */
  #define NHEAD		42	/*	Match non-head char */
  #define ALPHA		43	/*	Match alpha char */
  #define NALPHA		44	/*	Match non-alpha char */
  #define LOWER		45	/*	Match lowercase char */
  #define NLOWER		46	/*	Match non-lowercase char */
  #define UPPER		47	/*	Match uppercase char */
  #define NUPPER		48	/*	Match non-uppercase char */
  #define LAST_NL		NUPPER + ADD_NL
  #define WITH_NL(op)	((op) >= FIRST_NL && (op) <= LAST_NL)
  
  #define MOPEN		80  /* -89	 Mark this point in input as start of
  				 *	 \( subexpr.  MOPEN + 0 marks start of
  				 *	 match. */
  #define MCLOSE		90  /* -99	 Analogous to MOPEN.  MCLOSE + 0 marks
  				 *	 end of match. */
  #define BACKREF		100 /* -109 node Match same string again \1-\9 */
  
  #ifdef FEAT_SYN_HL
  # define ZOPEN		110 /* -119	 Mark this point in input as start of
  				 *	 \z( subexpr. */
  # define ZCLOSE		120 /* -129	 Analogous to ZOPEN. */
  # define ZREF		130 /* -139 node Match external submatch \z1-\z9 */
  #endif
  
  #define BRACE_COMPLEX	140 /* -149 node Match nodes between m & n times */
  
  #define NOPEN		150	/*	Mark this point in input as start of
  					\%( subexpr. */
  #define NCLOSE		151	/*	Analogous to NOPEN. */
  
  #define MULTIBYTECODE	200	/* mbc	Match one multi-byte character */
  #define RE_BOF		201	/*	Match "" at beginning of file. */
  #define RE_EOF		202	/*	Match "" at end of file. */
  #define CURSOR		203	/*	Match location of cursor. */
  
  #define RE_LNUM		204	/* nr cmp  Match line number */
  #define RE_COL		205	/* nr cmp  Match column number */
  #define RE_VCOL		206	/* nr cmp  Match virtual column number */
  
  #define RE_MARK		207	/* mark cmp  Match mark position */
  #define RE_VISUAL	208	/*	Match Visual area */
  #define RE_COMPOSING	209	/* any composing characters */
  
  /*
   * Magic characters have a special meaning, they don't match literally.
   * Magic characters are negative.  This separates them from literal characters
   * (possibly multi-byte).  Only ASCII characters can be Magic.
   */
  #define Magic(x)	((int)(x) - 256)
  #define un_Magic(x)	((x) + 256)
  #define is_Magic(x)	((x) < 0)
  
  static int no_Magic(int x);
  static int toggle_Magic(int x);
  
      static int
  no_Magic(int x)
  {
      if (is_Magic(x))
  	return un_Magic(x);
      return x;
  }
  
      static int
  toggle_Magic(int x)
  {
      if (is_Magic(x))
  	return un_Magic(x);
      return Magic(x);
  }
  
  /*
   * The first byte of the regexp internal "program" is actually this magic
   * number; the start node begins in the second byte.  It's used to catch the
   * most severe mutilation of the program by the caller.
   */
  
  #define REGMAGIC	0234
  
  /*
   * Opcode notes:
   *
   * BRANCH	The set of branches constituting a single choice are hooked
   *		together with their "next" pointers, since precedence prevents
   *		anything being concatenated to any individual branch.  The
   *		"next" pointer of the last BRANCH in a choice points to the
   *		thing following the whole choice.  This is also where the
   *		final "next" pointer of each individual branch points; each
   *		branch starts with the operand node of a BRANCH node.
   *
   * BACK		Normal "next" pointers all implicitly point forward; BACK
   *		exists to make loop structures possible.
   *
   * STAR,PLUS	'=', and complex '*' and '+', are implemented as circular
   *		BRANCH structures using BACK.  Simple cases (one character
   *		per match) are implemented with STAR and PLUS for speed
   *		and to minimize recursive plunges.
   *
   * BRACE_LIMITS	This is always followed by a BRACE_SIMPLE or BRACE_COMPLEX
   *		node, and defines the min and max limits to be used for that
   *		node.
   *
   * MOPEN,MCLOSE	...are numbered at compile time.
   * ZOPEN,ZCLOSE	...ditto
   */
  
  /*
   * A node is one char of opcode followed by two chars of "next" pointer.
   * "Next" pointers are stored as two 8-bit bytes, high order first.  The
   * value is a positive offset from the opcode of the node containing it.
   * An operand, if any, simply follows the node.  (Note that much of the
   * code generation knows about this implicit relationship.)
   *
   * Using two bytes for the "next" pointer is vast overkill for most things,
   * but allows patterns to get big without disasters.
   */
  #define OP(p)		((int)*(p))
  #define NEXT(p)		(((*((p) + 1) & 0377) << 8) + (*((p) + 2) & 0377))
  #define OPERAND(p)	((p) + 3)
  /* Obtain an operand that was stored as four bytes, MSB first. */
  #define OPERAND_MIN(p)	(((long)(p)[3] << 24) + ((long)(p)[4] << 16) \
  			+ ((long)(p)[5] << 8) + (long)(p)[6])
  /* Obtain a second operand stored as four bytes. */
  #define OPERAND_MAX(p)	OPERAND_MIN((p) + 4)
  /* Obtain a second single-byte operand stored after a four bytes operand. */
  #define OPERAND_CMP(p)	(p)[7]
  
  /*
   * Utility definitions.
   */
  #define UCHARAT(p)	((int)*(char_u *)(p))
  
  /* Used for an error (down from) vim_regcomp(): give the error message, set
   * rc_did_emsg and return NULL */
  #define EMSG_RET_NULL(m) return (EMSG(m), rc_did_emsg = TRUE, (void *)NULL)
  #define EMSG_RET_FAIL(m) return (EMSG(m), rc_did_emsg = TRUE, FAIL)
  #define EMSG2_RET_NULL(m, c) return (EMSG2((m), (c) ? "" : "\\"), rc_did_emsg = TRUE, (void *)NULL)
  #define EMSG2_RET_FAIL(m, c) return (EMSG2((m), (c) ? "" : "\\"), rc_did_emsg = TRUE, FAIL)
  #define EMSG_ONE_RET_NULL EMSG2_RET_NULL(_("E369: invalid item in %s%%[]"), reg_magic == MAGIC_ALL)
  
  #define MAX_LIMIT	(32767L << 16L)
  
  static int re_multi_type(int);
  static int cstrncmp(char_u *s1, char_u *s2, int *n);
  static char_u *cstrchr(char_u *, int);
  
  #ifdef BT_REGEXP_DUMP
  static void	regdump(char_u *, bt_regprog_T *);
  #endif
  #ifdef DEBUG
  static char_u	*regprop(char_u *);
  #endif
  
  static int re_mult_next(char *what);
  
  static char_u e_missingbracket[] = N_("E769: Missing ] after %s[");
  static char_u e_unmatchedpp[] = N_("E53: Unmatched %s%%(");
  static char_u e_unmatchedp[] = N_("E54: Unmatched %s(");
  static char_u e_unmatchedpar[] = N_("E55: Unmatched %s)");
  #ifdef FEAT_SYN_HL
  static char_u e_z_not_allowed[] = N_("E66: \\z( not allowed here");
  static char_u e_z1_not_allowed[] = N_("E67: \\z1 et al. not allowed here");
  #endif
  static char_u e_missing_sb[] = N_("E69: Missing ] after %s%%[");
  static char_u e_empty_sb[]  = N_("E70: Empty %s%%[]");
  #define NOT_MULTI	0
  #define MULTI_ONE	1
  #define MULTI_MULT	2
  /*
   * Return NOT_MULTI if c is not a "multi" operator.
   * Return MULTI_ONE if c is a single "multi" operator.
   * Return MULTI_MULT if c is a multi "multi" operator.
   */
      static int
  re_multi_type(int c)
  {
      if (c == Magic('@') || c == Magic('=') || c == Magic('?'))
  	return MULTI_ONE;
      if (c == Magic('*') || c == Magic('+') || c == Magic('{'))
  	return MULTI_MULT;
      return NOT_MULTI;
  }
  
  /*
   * Flags to be passed up and down.
   */
  #define HASWIDTH	0x1	/* Known never to match null string. */
  #define SIMPLE		0x2	/* Simple enough to be STAR/PLUS operand. */
  #define SPSTART		0x4	/* Starts with * or +. */
  #define HASNL		0x8	/* Contains some \n. */
  #define HASLOOKBH	0x10	/* Contains "\@<=" or "\@<!". */
  #define WORST		0	/* Worst case. */
  
  /*
   * When regcode is set to this value, code is not emitted and size is computed
   * instead.
   */
  #define JUST_CALC_SIZE	((char_u *) -1)
  
  static char_u		*reg_prev_sub = NULL;
  
  /*
   * REGEXP_INRANGE contains all characters which are always special in a []
   * range after '\'.
   * REGEXP_ABBR contains all characters which act as abbreviations after '\'.
   * These are:
   *  \n	- New line (NL).
   *  \r	- Carriage Return (CR).
   *  \t	- Tab (TAB).
   *  \e	- Escape (ESC).
   *  \b	- Backspace (Ctrl_H).
   *  \d  - Character code in decimal, eg \d123
   *  \o	- Character code in octal, eg \o80
   *  \x	- Character code in hex, eg \x4a
   *  \u	- Multibyte character code, eg \u20ac
   *  \U	- Long multibyte character code, eg \U12345678
   */
  static char_u REGEXP_INRANGE[] = "]^-n\\";
  static char_u REGEXP_ABBR[] = "nrtebdoxuU";
  
  static int	backslash_trans(int c);
  static int	get_char_class(char_u **pp);
  static int	get_equi_class(char_u **pp);
  static void	reg_equi_class(int c);
  static int	get_coll_element(char_u **pp);
  static char_u	*skip_anyof(char_u *p);
  static void	init_class_tab(void);
  
  /*
   * Translate '\x' to its control character, except "\n", which is Magic.
   */
      static int
  backslash_trans(int c)
  {
      switch (c)
      {
  	case 'r':   return CAR;
  	case 't':   return TAB;
  	case 'e':   return ESC;
  	case 'b':   return BS;
      }
      return c;
  }
  
  /*
   * Check for a character class name "[:name:]".  "pp" points to the '['.
   * Returns one of the CLASS_ items. CLASS_NONE means that no item was
   * recognized.  Otherwise "pp" is advanced to after the item.
   */
      static int
  get_char_class(char_u **pp)
  {
      static const char *(class_names[]) =
      {
  	"alnum:]",
  #define CLASS_ALNUM 0
  	"alpha:]",
  #define CLASS_ALPHA 1
  	"blank:]",
  #define CLASS_BLANK 2
  	"cntrl:]",
  #define CLASS_CNTRL 3
  	"digit:]",
  #define CLASS_DIGIT 4
  	"graph:]",
  #define CLASS_GRAPH 5
  	"lower:]",
  #define CLASS_LOWER 6
  	"print:]",
  #define CLASS_PRINT 7
  	"punct:]",
  #define CLASS_PUNCT 8
  	"space:]",
  #define CLASS_SPACE 9
  	"upper:]",
  #define CLASS_UPPER 10
  	"xdigit:]",
  #define CLASS_XDIGIT 11
  	"tab:]",
  #define CLASS_TAB 12
  	"return:]",
  #define CLASS_RETURN 13
  	"backspace:]",
  #define CLASS_BACKSPACE 14
  	"escape:]",
  #define CLASS_ESCAPE 15
      };
  #define CLASS_NONE 99
      int i;
  
      if ((*pp)[1] == ':')
      {
  	for (i = 0; i < (int)(sizeof(class_names) / sizeof(*class_names)); ++i)
  	    if (STRNCMP(*pp + 2, class_names[i], STRLEN(class_names[i])) == 0)
  	    {
  		*pp += STRLEN(class_names[i]) + 2;
  		return i;
  	    }
      }
      return CLASS_NONE;
  }
  
  /*
   * Specific version of character class functions.
   * Using a table to keep this fast.
   */
  static short	class_tab[256];
  
  #define	    RI_DIGIT	0x01
  #define	    RI_HEX	0x02
  #define	    RI_OCTAL	0x04
  #define	    RI_WORD	0x08
  #define	    RI_HEAD	0x10
  #define	    RI_ALPHA	0x20
  #define	    RI_LOWER	0x40
  #define	    RI_UPPER	0x80
  #define	    RI_WHITE	0x100
  
      static void
  init_class_tab(void)
  {
      int		i;
      static int	done = FALSE;
  
      if (done)
  	return;
  
      for (i = 0; i < 256; ++i)
      {
  	if (i >= '0' && i <= '7')
  	    class_tab[i] = RI_DIGIT + RI_HEX + RI_OCTAL + RI_WORD;
  	else if (i >= '8' && i <= '9')
  	    class_tab[i] = RI_DIGIT + RI_HEX + RI_WORD;
  	else if (i >= 'a' && i <= 'f')
  	    class_tab[i] = RI_HEX + RI_WORD + RI_HEAD + RI_ALPHA + RI_LOWER;
  #ifdef EBCDIC
  	else if ((i >= 'g' && i <= 'i') || (i >= 'j' && i <= 'r')
  						    || (i >= 's' && i <= 'z'))
  #else
  	else if (i >= 'g' && i <= 'z')
  #endif
  	    class_tab[i] = RI_WORD + RI_HEAD + RI_ALPHA + RI_LOWER;
  	else if (i >= 'A' && i <= 'F')
  	    class_tab[i] = RI_HEX + RI_WORD + RI_HEAD + RI_ALPHA + RI_UPPER;
  #ifdef EBCDIC
  	else if ((i >= 'G' && i <= 'I') || ( i >= 'J' && i <= 'R')
  						    || (i >= 'S' && i <= 'Z'))
  #else
  	else if (i >= 'G' && i <= 'Z')
  #endif
  	    class_tab[i] = RI_WORD + RI_HEAD + RI_ALPHA + RI_UPPER;
  	else if (i == '_')
  	    class_tab[i] = RI_WORD + RI_HEAD;
  	else
  	    class_tab[i] = 0;
      }
      class_tab[' '] |= RI_WHITE;
      class_tab['\t'] |= RI_WHITE;
      done = TRUE;
  }
  
  #ifdef FEAT_MBYTE
  # define ri_digit(c)	(c < 0x100 && (class_tab[c] & RI_DIGIT))
  # define ri_hex(c)	(c < 0x100 && (class_tab[c] & RI_HEX))
  # define ri_octal(c)	(c < 0x100 && (class_tab[c] & RI_OCTAL))
  # define ri_word(c)	(c < 0x100 && (class_tab[c] & RI_WORD))
  # define ri_head(c)	(c < 0x100 && (class_tab[c] & RI_HEAD))
  # define ri_alpha(c)	(c < 0x100 && (class_tab[c] & RI_ALPHA))
  # define ri_lower(c)	(c < 0x100 && (class_tab[c] & RI_LOWER))
  # define ri_upper(c)	(c < 0x100 && (class_tab[c] & RI_UPPER))
  # define ri_white(c)	(c < 0x100 && (class_tab[c] & RI_WHITE))
  #else
  # define ri_digit(c)	(class_tab[c] & RI_DIGIT)
  # define ri_hex(c)	(class_tab[c] & RI_HEX)
  # define ri_octal(c)	(class_tab[c] & RI_OCTAL)
  # define ri_word(c)	(class_tab[c] & RI_WORD)
  # define ri_head(c)	(class_tab[c] & RI_HEAD)
  # define ri_alpha(c)	(class_tab[c] & RI_ALPHA)
  # define ri_lower(c)	(class_tab[c] & RI_LOWER)
  # define ri_upper(c)	(class_tab[c] & RI_UPPER)
  # define ri_white(c)	(class_tab[c] & RI_WHITE)
  #endif
  
  /* flags for regflags */
  #define RF_ICASE    1	/* ignore case */
  #define RF_NOICASE  2	/* don't ignore case */
  #define RF_HASNL    4	/* can match a NL */
  #define RF_ICOMBINE 8	/* ignore combining characters */
  #define RF_LOOKBH   16	/* uses "\@<=" or "\@<!" */
  
  /*
   * Global work variables for vim_regcomp().
   */
  
  static char_u	*regparse;	/* Input-scan pointer. */
  static int	prevchr_len;	/* byte length of previous char */
  static int	num_complex_braces; /* Complex \{...} count */
  static int	regnpar;	/* () count. */
  #ifdef FEAT_SYN_HL
  static int	regnzpar;	/* \z() count. */
  static int	re_has_z;	/* \z item detected */
  #endif
  static char_u	*regcode;	/* Code-emit pointer, or JUST_CALC_SIZE */
  static long	regsize;	/* Code size. */
  static int	reg_toolong;	/* TRUE when offset out of range */
  static char_u	had_endbrace[NSUBEXP];	/* flags, TRUE if end of () found */
  static unsigned	regflags;	/* RF_ flags for prog */
  static long	brace_min[10];	/* Minimums for complex brace repeats */
  static long	brace_max[10];	/* Maximums for complex brace repeats */
  static int	brace_count[10]; /* Current counts for complex brace repeats */
  #if defined(FEAT_SYN_HL) || defined(PROTO)
  static int	had_eol;	/* TRUE when EOL found by vim_regcomp() */
  #endif
  static int	one_exactly = FALSE;	/* only do one char for EXACTLY */
  
  static int	reg_magic;	/* magicness of the pattern: */
  #define MAGIC_NONE	1	/* "\V" very unmagic */
  #define MAGIC_OFF	2	/* "\M" or 'magic' off */
  #define MAGIC_ON	3	/* "\m" or 'magic' */
  #define MAGIC_ALL	4	/* "\v" very magic */
  
  static int	reg_string;	/* matching with a string instead of a buffer
  				   line */
  static int	reg_strict;	/* "[abc" is illegal */
  
  /*
   * META contains all characters that may be magic, except '^' and '$'.
   */
  
  #ifdef EBCDIC
  static char_u META[] = "%&()*+.123456789<=>?@ACDFHIKLMOPSUVWX[_acdfhiklmnopsuvwxz{|~";
  #else
  /* META[] is used often enough to justify turning it into a table. */
  static char_u META_flags[] = {
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  /*		   %  &     (  )  *  +	      .    */
      0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0,
  /*     1  2  3	4  5  6  7  8  9	<  =  >  ? */
      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1,
  /*  @  A     C	D     F     H  I     K	L  M	 O */
      1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1,
  /*  P	     S	   U  V  W  X	  Z  [		 _ */
      1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1,
  /*     a     c	d     f     h  i     k	l  m  n  o */
      0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1,
  /*  p	     s	   u  v  w  x	  z  {	|     ~    */
      1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1
  };
  #endif
  
  static int	curchr;		/* currently parsed character */
  /* Previous character.  Note: prevchr is sometimes -1 when we are not at the
   * start, eg in /[ ^I]^ the pattern was never found even if it existed,
   * because ^ was taken to be magic -- webb */
  static int	prevchr;
  static int	prevprevchr;	/* previous-previous character */
  static int	nextchr;	/* used for ungetchr() */
  
  /* arguments for reg() */
  #define REG_NOPAREN	0	/* toplevel reg() */
  #define REG_PAREN	1	/* \(\) */
  #define REG_ZPAREN	2	/* \z(\) */
  #define REG_NPAREN	3	/* \%(\) */
  
  typedef struct
  {
       char_u	*regparse;
       int	prevchr_len;
       int	curchr;
       int	prevchr;
       int	prevprevchr;
       int	nextchr;
       int	at_start;
       int	prev_at_start;
       int	regnpar;
  } parse_state_T;
  
  /*
   * Forward declarations for vim_regcomp()'s friends.
   */
  static void	initchr(char_u *);
  static void	save_parse_state(parse_state_T *ps);
  static void	restore_parse_state(parse_state_T *ps);
  static int	getchr(void);
  static void	skipchr_keepstart(void);
  static int	peekchr(void);
  static void	skipchr(void);
  static void	ungetchr(void);
  static int	gethexchrs(int maxinputlen);
  static int	getoctchrs(void);
  static int	getdecchrs(void);
  static int	coll_get_char(void);
  static void	regcomp_start(char_u *expr, int flags);
  static char_u	*reg(int, int *);
  static char_u	*regbranch(int *flagp);
  static char_u	*regconcat(int *flagp);
  static char_u	*regpiece(int *);
  static char_u	*regatom(int *);
  static char_u	*regnode(int);
  #ifdef FEAT_MBYTE
  static int	use_multibytecode(int c);
  #endif
  static int	prog_magic_wrong(void);
  static char_u	*regnext(char_u *);
  static void	regc(int b);
  #ifdef FEAT_MBYTE
  static void	regmbc(int c);
  # define REGMBC(x) regmbc(x);
  # define CASEMBC(x) case x:
  #else
  # define regmbc(c) regc(c)
  # define REGMBC(x)
  # define CASEMBC(x)
  #endif
  static void	reginsert(int, char_u *);
  static void	reginsert_nr(int op, long val, char_u *opnd);
  static void	reginsert_limits(int, long, long, char_u *);
  static char_u	*re_put_long(char_u *pr, long_u val);
  static int	read_limits(long *, long *);
  static void	regtail(char_u *, char_u *);
  static void	regoptail(char_u *, char_u *);
  
  static regengine_T bt_regengine;
  static regengine_T nfa_regengine;
  
  /*
   * Return TRUE if compiled regular expression "prog" can match a line break.
   */
      int
  re_multiline(regprog_T *prog)
  {
      return (prog->regflags & RF_HASNL);
  }
  
  /*
   * Return TRUE if compiled regular expression "prog" looks before the start
   * position (pattern contains "\@<=" or "\@<!").
   */
      int
  re_lookbehind(regprog_T *prog)
  {
      return (prog->regflags & RF_LOOKBH);
  }
  
  /*
   * Check for an equivalence class name "[=a=]".  "pp" points to the '['.
   * Returns a character representing the class. Zero means that no item was
   * recognized.  Otherwise "pp" is advanced to after the item.
   */
      static int
  get_equi_class(char_u **pp)
  {
      int		c;
      int		l = 1;
      char_u	*p = *pp;
  
      if (p[1] == '=')
      {
  #ifdef FEAT_MBYTE
  	if (has_mbyte)
  	    l = (*mb_ptr2len)(p + 2);
  #endif
  	if (p[l + 2] == '=' && p[l + 3] == ']')
  	{
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  		c = mb_ptr2char(p + 2);
  	    else
  #endif
  		c = p[2];
  	    *pp += l + 4;
  	    return c;
  	}
      }
      return 0;
  }
  
  #ifdef EBCDIC
  /*
   * Table for equivalence class "c". (IBM-1047)
   */
  char *EQUIVAL_CLASS_C[16] = {
      "A\x62\x63\x64\x65\x66\x67",
      "C\x68",
      "E\x71\x72\x73\x74",
      "I\x75\x76\x77\x78",
      "N\x69",
      "O\xEB\xEC\xED\xEE\xEF",
      "U\xFB\xFC\xFD\xFE",
      "Y\xBA",
      "a\x42\x43\x44\x45\x46\x47",
      "c\x48",
      "e\x51\x52\x53\x54",
      "i\x55\x56\x57\x58",
      "n\x49",
      "o\xCB\xCC\xCD\xCE\xCF",
      "u\xDB\xDC\xDD\xDE",
      "y\x8D\xDF",
  };
  #endif
  
  /*
   * Produce the bytes for equivalence class "c".
   * Currently only handles latin1, latin9 and utf-8.
   * NOTE: When changing this function, also change nfa_emit_equi_class()
   */
      static void
  reg_equi_class(int c)
  {
  #ifdef FEAT_MBYTE
      if (enc_utf8 || STRCMP(p_enc, "latin1") == 0
  					 || STRCMP(p_enc, "iso-8859-15") == 0)
  #endif
      {
  #ifdef EBCDIC
  	int i;
  
  	/* This might be slower than switch/case below. */
  	for (i = 0; i < 16; i++)
  	{
  	    if (vim_strchr(EQUIVAL_CLASS_C[i], c) != NULL)
  	    {
  		char *p = EQUIVAL_CLASS_C[i];
  
  		while (*p != 0)
  		    regmbc(*p++);
  		return;
  	    }
  	}
  #else
  	switch (c)
  	{
  	    /* Do not use '\300' style, it results in a negative number. */
  	    case 'A': case 0xc0: case 0xc1: case 0xc2:
  	    case 0xc3: case 0xc4: case 0xc5:
  	    CASEMBC(0x100) CASEMBC(0x102) CASEMBC(0x104) CASEMBC(0x1cd)
  	    CASEMBC(0x1de) CASEMBC(0x1e0) CASEMBC(0x1ea2)
  		      regmbc('A'); regmbc(0xc0); regmbc(0xc1);
  		      regmbc(0xc2); regmbc(0xc3); regmbc(0xc4);
  		      regmbc(0xc5);
  		      REGMBC(0x100) REGMBC(0x102) REGMBC(0x104)
  		      REGMBC(0x1cd) REGMBC(0x1de) REGMBC(0x1e0)
  		      REGMBC(0x1ea2)
  		      return;
  	    case 'B': CASEMBC(0x1e02) CASEMBC(0x1e06)
  		      regmbc('B'); REGMBC(0x1e02) REGMBC(0x1e06)
  		      return;
  	    case 'C': case 0xc7:
  	    CASEMBC(0x106) CASEMBC(0x108) CASEMBC(0x10a) CASEMBC(0x10c)
  		      regmbc('C'); regmbc(0xc7);
  		      REGMBC(0x106) REGMBC(0x108) REGMBC(0x10a)
  		      REGMBC(0x10c)
  		      return;
  	    case 'D': CASEMBC(0x10e) CASEMBC(0x110) CASEMBC(0x1e0a)
  	    CASEMBC(0x1e0e) CASEMBC(0x1e10)
  		      regmbc('D'); REGMBC(0x10e) REGMBC(0x110)
  		      REGMBC(0x1e0a) REGMBC(0x1e0e) REGMBC(0x1e10)
  		      return;
  	    case 'E': case 0xc8: case 0xc9: case 0xca: case 0xcb:
  	    CASEMBC(0x112) CASEMBC(0x114) CASEMBC(0x116) CASEMBC(0x118)
  	    CASEMBC(0x11a) CASEMBC(0x1eba) CASEMBC(0x1ebc)
  		      regmbc('E'); regmbc(0xc8); regmbc(0xc9);
  		      regmbc(0xca); regmbc(0xcb);
  		      REGMBC(0x112) REGMBC(0x114) REGMBC(0x116)
  		      REGMBC(0x118) REGMBC(0x11a) REGMBC(0x1eba)
  		      REGMBC(0x1ebc)
  		      return;
  	    case 'F': CASEMBC(0x1e1e)
  		      regmbc('F'); REGMBC(0x1e1e)
  		      return;
  	    case 'G': CASEMBC(0x11c) CASEMBC(0x11e) CASEMBC(0x120)
  	    CASEMBC(0x122) CASEMBC(0x1e4) CASEMBC(0x1e6) CASEMBC(0x1f4)
  	    CASEMBC(0x1e20)
  		      regmbc('G'); REGMBC(0x11c) REGMBC(0x11e)
  		      REGMBC(0x120) REGMBC(0x122) REGMBC(0x1e4)
  		      REGMBC(0x1e6) REGMBC(0x1f4) REGMBC(0x1e20)
  		      return;
  	    case 'H': CASEMBC(0x124) CASEMBC(0x126) CASEMBC(0x1e22)
  	    CASEMBC(0x1e26) CASEMBC(0x1e28)
  		      regmbc('H'); REGMBC(0x124) REGMBC(0x126)
  		      REGMBC(0x1e22) REGMBC(0x1e26) REGMBC(0x1e28)
  		      return;
  	    case 'I': case 0xcc: case 0xcd: case 0xce: case 0xcf:
  	    CASEMBC(0x128) CASEMBC(0x12a) CASEMBC(0x12c) CASEMBC(0x12e)
  	    CASEMBC(0x130) CASEMBC(0x1cf) CASEMBC(0x1ec8)
  		      regmbc('I'); regmbc(0xcc); regmbc(0xcd);
  		      regmbc(0xce); regmbc(0xcf);
  		      REGMBC(0x128) REGMBC(0x12a) REGMBC(0x12c)
  		      REGMBC(0x12e) REGMBC(0x130) REGMBC(0x1cf)
  		      REGMBC(0x1ec8)
  		      return;
  	    case 'J': CASEMBC(0x134)
  		      regmbc('J'); REGMBC(0x134)
  		      return;
  	    case 'K': CASEMBC(0x136) CASEMBC(0x1e8) CASEMBC(0x1e30)
  	    CASEMBC(0x1e34)
  		      regmbc('K'); REGMBC(0x136) REGMBC(0x1e8)
  		      REGMBC(0x1e30) REGMBC(0x1e34)
  		      return;
  	    case 'L': CASEMBC(0x139) CASEMBC(0x13b) CASEMBC(0x13d)
  	    CASEMBC(0x13f) CASEMBC(0x141) CASEMBC(0x1e3a)
  		      regmbc('L'); REGMBC(0x139) REGMBC(0x13b)
  		      REGMBC(0x13d) REGMBC(0x13f) REGMBC(0x141)
  		      REGMBC(0x1e3a)
  		      return;
  	    case 'M': CASEMBC(0x1e3e) CASEMBC(0x1e40)
  		      regmbc('M'); REGMBC(0x1e3e) REGMBC(0x1e40)
  		      return;
  	    case 'N': case 0xd1:
  	    CASEMBC(0x143) CASEMBC(0x145) CASEMBC(0x147) CASEMBC(0x1e44)
  	    CASEMBC(0x1e48)
  		      regmbc('N'); regmbc(0xd1);
  		      REGMBC(0x143) REGMBC(0x145) REGMBC(0x147)
  		      REGMBC(0x1e44) REGMBC(0x1e48)
  		      return;
  	    case 'O': case 0xd2: case 0xd3: case 0xd4: case 0xd5:
  	    case 0xd6: case 0xd8:
  	    CASEMBC(0x14c) CASEMBC(0x14e) CASEMBC(0x150) CASEMBC(0x1a0)
  	    CASEMBC(0x1d1) CASEMBC(0x1ea) CASEMBC(0x1ec) CASEMBC(0x1ece)
  		      regmbc('O'); regmbc(0xd2); regmbc(0xd3);
  		      regmbc(0xd4); regmbc(0xd5); regmbc(0xd6);
  		      regmbc(0xd8);
  		      REGMBC(0x14c) REGMBC(0x14e) REGMBC(0x150)
  		      REGMBC(0x1a0) REGMBC(0x1d1) REGMBC(0x1ea)
  		      REGMBC(0x1ec) REGMBC(0x1ece)
  		      return;
  	    case 'P': case 0x1e54: case 0x1e56:
  		      regmbc('P'); REGMBC(0x1e54) REGMBC(0x1e56)
  		      return;
  	    case 'R': CASEMBC(0x154) CASEMBC(0x156) CASEMBC(0x158)
  	    CASEMBC(0x1e58) CASEMBC(0x1e5e)
  		      regmbc('R'); REGMBC(0x154) REGMBC(0x156) REGMBC(0x158)
  		      REGMBC(0x1e58) REGMBC(0x1e5e)
  		      return;
  	    case 'S': CASEMBC(0x15a) CASEMBC(0x15c) CASEMBC(0x15e)
  	    CASEMBC(0x160) CASEMBC(0x1e60)
  		      regmbc('S'); REGMBC(0x15a) REGMBC(0x15c)
  		      REGMBC(0x15e) REGMBC(0x160) REGMBC(0x1e60)
  		      return;
  	    case 'T': CASEMBC(0x162) CASEMBC(0x164) CASEMBC(0x166)
  	    CASEMBC(0x1e6a) CASEMBC(0x1e6e)
  		      regmbc('T'); REGMBC(0x162) REGMBC(0x164)
  		      REGMBC(0x166) REGMBC(0x1e6a) REGMBC(0x1e6e)
  		      return;
  	    case 'U': case 0xd9: case 0xda: case 0xdb: case 0xdc:
  	    CASEMBC(0x168) CASEMBC(0x16a) CASEMBC(0x16c) CASEMBC(0x16e)
  	    CASEMBC(0x170) CASEMBC(0x172) CASEMBC(0x1af) CASEMBC(0x1d3)
  	    CASEMBC(0x1ee6)
  		      regmbc('U'); regmbc(0xd9); regmbc(0xda);
  		      regmbc(0xdb); regmbc(0xdc);
  		      REGMBC(0x168) REGMBC(0x16a) REGMBC(0x16c)
  		      REGMBC(0x16e) REGMBC(0x170) REGMBC(0x172)
  		      REGMBC(0x1af) REGMBC(0x1d3) REGMBC(0x1ee6)
  		      return;
  	    case 'V': CASEMBC(0x1e7c)
  		      regmbc('V'); REGMBC(0x1e7c)
  		      return;
  	    case 'W': CASEMBC(0x174) CASEMBC(0x1e80) CASEMBC(0x1e82)
  	    CASEMBC(0x1e84) CASEMBC(0x1e86)
  		      regmbc('W'); REGMBC(0x174) REGMBC(0x1e80)
  		      REGMBC(0x1e82) REGMBC(0x1e84) REGMBC(0x1e86)
  		      return;
  	    case 'X': CASEMBC(0x1e8a) CASEMBC(0x1e8c)
  		      regmbc('X'); REGMBC(0x1e8a) REGMBC(0x1e8c)
  		      return;
  	    case 'Y': case 0xdd:
  	    CASEMBC(0x176) CASEMBC(0x178) CASEMBC(0x1e8e) CASEMBC(0x1ef2)
  	    CASEMBC(0x1ef6) CASEMBC(0x1ef8)
  		      regmbc('Y'); regmbc(0xdd);
  		      REGMBC(0x176) REGMBC(0x178) REGMBC(0x1e8e)
  		      REGMBC(0x1ef2) REGMBC(0x1ef6) REGMBC(0x1ef8)
  		      return;
  	    case 'Z': CASEMBC(0x179) CASEMBC(0x17b) CASEMBC(0x17d)
  	    CASEMBC(0x1b5) CASEMBC(0x1e90) CASEMBC(0x1e94)
  		      regmbc('Z'); REGMBC(0x179) REGMBC(0x17b)
  		      REGMBC(0x17d) REGMBC(0x1b5) REGMBC(0x1e90)
  		      REGMBC(0x1e94)
  		      return;
  	    case 'a': case 0xe0: case 0xe1: case 0xe2:
  	    case 0xe3: case 0xe4: case 0xe5:
  	    CASEMBC(0x101) CASEMBC(0x103) CASEMBC(0x105) CASEMBC(0x1ce)
  	    CASEMBC(0x1df) CASEMBC(0x1e1) CASEMBC(0x1ea3)
  		      regmbc('a'); regmbc(0xe0); regmbc(0xe1);
  		      regmbc(0xe2); regmbc(0xe3); regmbc(0xe4);
  		      regmbc(0xe5);
  		      REGMBC(0x101) REGMBC(0x103) REGMBC(0x105)
  		      REGMBC(0x1ce) REGMBC(0x1df) REGMBC(0x1e1)
  		      REGMBC(0x1ea3)
  		      return;
  	    case 'b': CASEMBC(0x1e03) CASEMBC(0x1e07)
  		      regmbc('b'); REGMBC(0x1e03) REGMBC(0x1e07)
  		      return;
  	    case 'c': case 0xe7:
  	    CASEMBC(0x107) CASEMBC(0x109) CASEMBC(0x10b) CASEMBC(0x10d)
  		      regmbc('c'); regmbc(0xe7);
  		      REGMBC(0x107) REGMBC(0x109) REGMBC(0x10b)
  		      REGMBC(0x10d)
  		      return;
  	    case 'd': CASEMBC(0x10f) CASEMBC(0x111) CASEMBC(0x1e0b)
  	    CASEMBC(0x1e0f) CASEMBC(0x1e11)
  		      regmbc('d'); REGMBC(0x10f) REGMBC(0x111)
  		      REGMBC(0x1e0b) REGMBC(0x1e0f) REGMBC(0x1e11)
  		      return;
  	    case 'e': case 0xe8: case 0xe9: case 0xea: case 0xeb:
  	    CASEMBC(0x113) CASEMBC(0x115) CASEMBC(0x117) CASEMBC(0x119)
  	    CASEMBC(0x11b) CASEMBC(0x1ebb) CASEMBC(0x1ebd)
  		      regmbc('e'); regmbc(0xe8); regmbc(0xe9);
  		      regmbc(0xea); regmbc(0xeb);
  		      REGMBC(0x113) REGMBC(0x115) REGMBC(0x117)
  		      REGMBC(0x119) REGMBC(0x11b) REGMBC(0x1ebb)
  		      REGMBC(0x1ebd)
  		      return;
  	    case 'f': CASEMBC(0x1e1f)
  		      regmbc('f'); REGMBC(0x1e1f)
  		      return;
  	    case 'g': CASEMBC(0x11d) CASEMBC(0x11f) CASEMBC(0x121)
  	    CASEMBC(0x123) CASEMBC(0x1e5) CASEMBC(0x1e7) CASEMBC(0x1f5)
  	    CASEMBC(0x1e21)
  		      regmbc('g'); REGMBC(0x11d) REGMBC(0x11f)
  		      REGMBC(0x121) REGMBC(0x123) REGMBC(0x1e5)
  		      REGMBC(0x1e7) REGMBC(0x1f5) REGMBC(0x1e21)
  		      return;
  	    case 'h': CASEMBC(0x125) CASEMBC(0x127) CASEMBC(0x1e23)
  	    CASEMBC(0x1e27) CASEMBC(0x1e29) CASEMBC(0x1e96)
  		      regmbc('h'); REGMBC(0x125) REGMBC(0x127)
  		      REGMBC(0x1e23) REGMBC(0x1e27) REGMBC(0x1e29)
  		      REGMBC(0x1e96)
  		      return;
  	    case 'i': case 0xec: case 0xed: case 0xee: case 0xef:
  	    CASEMBC(0x129) CASEMBC(0x12b) CASEMBC(0x12d) CASEMBC(0x12f)
  	    CASEMBC(0x1d0) CASEMBC(0x1ec9)
  		      regmbc('i'); regmbc(0xec); regmbc(0xed);
  		      regmbc(0xee); regmbc(0xef);
  		      REGMBC(0x129) REGMBC(0x12b) REGMBC(0x12d)
  		      REGMBC(0x12f) REGMBC(0x1d0) REGMBC(0x1ec9)
  		      return;
  	    case 'j': CASEMBC(0x135) CASEMBC(0x1f0)
  		      regmbc('j'); REGMBC(0x135) REGMBC(0x1f0)
  		      return;
  	    case 'k': CASEMBC(0x137) CASEMBC(0x1e9) CASEMBC(0x1e31)
  	    CASEMBC(0x1e35)
  		      regmbc('k'); REGMBC(0x137) REGMBC(0x1e9)
  		      REGMBC(0x1e31) REGMBC(0x1e35)
  		      return;
  	    case 'l': CASEMBC(0x13a) CASEMBC(0x13c) CASEMBC(0x13e)
  	    CASEMBC(0x140) CASEMBC(0x142) CASEMBC(0x1e3b)
  		      regmbc('l'); REGMBC(0x13a) REGMBC(0x13c)
  		      REGMBC(0x13e) REGMBC(0x140) REGMBC(0x142)
  		      REGMBC(0x1e3b)
  		      return;
  	    case 'm': CASEMBC(0x1e3f) CASEMBC(0x1e41)
  		      regmbc('m'); REGMBC(0x1e3f) REGMBC(0x1e41)
  		      return;
  	    case 'n': case 0xf1:
  	    CASEMBC(0x144) CASEMBC(0x146) CASEMBC(0x148) CASEMBC(0x149)
  	    CASEMBC(0x1e45) CASEMBC(0x1e49)
  		      regmbc('n'); regmbc(0xf1);
  		      REGMBC(0x144) REGMBC(0x146) REGMBC(0x148)
  		      REGMBC(0x149) REGMBC(0x1e45) REGMBC(0x1e49)
  		      return;
  	    case 'o': case 0xf2: case 0xf3: case 0xf4: case 0xf5:
  	    case 0xf6: case 0xf8:
  	    CASEMBC(0x14d) CASEMBC(0x14f) CASEMBC(0x151) CASEMBC(0x1a1)
  	    CASEMBC(0x1d2) CASEMBC(0x1eb) CASEMBC(0x1ed) CASEMBC(0x1ecf)
  		      regmbc('o'); regmbc(0xf2); regmbc(0xf3);
  		      regmbc(0xf4); regmbc(0xf5); regmbc(0xf6);
  		      regmbc(0xf8);
  		      REGMBC(0x14d) REGMBC(0x14f) REGMBC(0x151)
  		      REGMBC(0x1a1) REGMBC(0x1d2) REGMBC(0x1eb)
  		      REGMBC(0x1ed) REGMBC(0x1ecf)
  		      return;
  	    case 'p': CASEMBC(0x1e55) CASEMBC(0x1e57)
  		      regmbc('p'); REGMBC(0x1e55) REGMBC(0x1e57)
  		      return;
  	    case 'r': CASEMBC(0x155) CASEMBC(0x157) CASEMBC(0x159)
  	    CASEMBC(0x1e59) CASEMBC(0x1e5f)
  		      regmbc('r'); REGMBC(0x155) REGMBC(0x157) REGMBC(0x159)
  		      REGMBC(0x1e59) REGMBC(0x1e5f)
  		      return;
  	    case 's': CASEMBC(0x15b) CASEMBC(0x15d) CASEMBC(0x15f)
  	    CASEMBC(0x161) CASEMBC(0x1e61)
  		      regmbc('s'); REGMBC(0x15b) REGMBC(0x15d)
  		      REGMBC(0x15f) REGMBC(0x161) REGMBC(0x1e61)
  		      return;
  	    case 't': CASEMBC(0x163) CASEMBC(0x165) CASEMBC(0x167)
  	    CASEMBC(0x1e6b) CASEMBC(0x1e6f) CASEMBC(0x1e97)
  		      regmbc('t'); REGMBC(0x163) REGMBC(0x165) REGMBC(0x167)
  		      REGMBC(0x1e6b) REGMBC(0x1e6f) REGMBC(0x1e97)
  		      return;
  	    case 'u': case 0xf9: case 0xfa: case 0xfb: case 0xfc:
  	    CASEMBC(0x169) CASEMBC(0x16b) CASEMBC(0x16d) CASEMBC(0x16f)
  	    CASEMBC(0x171) CASEMBC(0x173) CASEMBC(0x1b0) CASEMBC(0x1d4)
  	    CASEMBC(0x1ee7)
  		      regmbc('u'); regmbc(0xf9); regmbc(0xfa);
  		      regmbc(0xfb); regmbc(0xfc);
  		      REGMBC(0x169) REGMBC(0x16b) REGMBC(0x16d)
  		      REGMBC(0x16f) REGMBC(0x171) REGMBC(0x173)
  		      REGMBC(0x1b0) REGMBC(0x1d4) REGMBC(0x1ee7)
  		      return;
  	    case 'v': CASEMBC(0x1e7d)
  		      regmbc('v'); REGMBC(0x1e7d)
  		      return;
  	    case 'w': CASEMBC(0x175) CASEMBC(0x1e81) CASEMBC(0x1e83)
  	    CASEMBC(0x1e85) CASEMBC(0x1e87) CASEMBC(0x1e98)
  		      regmbc('w'); REGMBC(0x175) REGMBC(0x1e81)
  		      REGMBC(0x1e83) REGMBC(0x1e85) REGMBC(0x1e87)
  		      REGMBC(0x1e98)
  		      return;
  	    case 'x': CASEMBC(0x1e8b) CASEMBC(0x1e8d)
  		      regmbc('x'); REGMBC(0x1e8b) REGMBC(0x1e8d)
  		      return;
  	    case 'y': case 0xfd: case 0xff:
  	    CASEMBC(0x177) CASEMBC(0x1e8f) CASEMBC(0x1e99)
  	    CASEMBC(0x1ef3) CASEMBC(0x1ef7) CASEMBC(0x1ef9)
  		      regmbc('y'); regmbc(0xfd); regmbc(0xff);
  		      REGMBC(0x177) REGMBC(0x1e8f) REGMBC(0x1e99)
  		      REGMBC(0x1ef3) REGMBC(0x1ef7) REGMBC(0x1ef9)
  		      return;
  	    case 'z': CASEMBC(0x17a) CASEMBC(0x17c) CASEMBC(0x17e)
  	    CASEMBC(0x1b6) CASEMBC(0x1e91) CASEMBC(0x1e95)
  		      regmbc('z'); REGMBC(0x17a) REGMBC(0x17c)
  		      REGMBC(0x17e) REGMBC(0x1b6) REGMBC(0x1e91)
  		      REGMBC(0x1e95)
  		      return;
  	}
  #endif
      }
      regmbc(c);
  }
  
  /*
   * Check for a collating element "[.a.]".  "pp" points to the '['.
   * Returns a character. Zero means that no item was recognized.  Otherwise
   * "pp" is advanced to after the item.
   * Currently only single characters are recognized!
   */
      static int
  get_coll_element(char_u **pp)
  {
      int		c;
      int		l = 1;
      char_u	*p = *pp;
  
      if (p[0] != NUL && p[1] == '.')
      {
  #ifdef FEAT_MBYTE
  	if (has_mbyte)
  	    l = (*mb_ptr2len)(p + 2);
  #endif
  	if (p[l + 2] == '.' && p[l + 3] == ']')
  	{
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  		c = mb_ptr2char(p + 2);
  	    else
  #endif
  		c = p[2];
  	    *pp += l + 4;
  	    return c;
  	}
      }
      return 0;
  }
  
  static void get_cpo_flags(void);
  static int reg_cpo_lit; /* 'cpoptions' contains 'l' flag */
  static int reg_cpo_bsl; /* 'cpoptions' contains '\' flag */
  
      static void
  get_cpo_flags(void)
  {
      reg_cpo_lit = vim_strchr(p_cpo, CPO_LITERAL) != NULL;
      reg_cpo_bsl = vim_strchr(p_cpo, CPO_BACKSL) != NULL;
  }
  
  /*
   * Skip over a "[]" range.
   * "p" must point to the character after the '['.
   * The returned pointer is on the matching ']', or the terminating NUL.
   */
      static char_u *
  skip_anyof(char_u *p)
  {
  #ifdef FEAT_MBYTE
      int		l;
  #endif
  
      if (*p == '^')	/* Complement of range. */
  	++p;
      if (*p == ']' || *p == '-')
  	++p;
      while (*p != NUL && *p != ']')
      {
  #ifdef FEAT_MBYTE
  	if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
  	    p += l;
  	else
  #endif
  	    if (*p == '-')
  	    {
  		++p;
  		if (*p != ']' && *p != NUL)
  		    mb_ptr_adv(p);
  	    }
  	else if (*p == '\\'
  		&& !reg_cpo_bsl
  		&& (vim_strchr(REGEXP_INRANGE, p[1]) != NULL
  		    || (!reg_cpo_lit && vim_strchr(REGEXP_ABBR, p[1]) != NULL)))
  	    p += 2;
  	else if (*p == '[')
  	{
  	    if (get_char_class(&p) == CLASS_NONE
  		    && get_equi_class(&p) == 0
  		    && get_coll_element(&p) == 0
  		    && *p != NUL)
  		++p; /* it is not a class name and not NUL */
  	}
  	else
  	    ++p;
      }
  
      return p;
  }
  
  /*
   * Skip past regular expression.
   * Stop at end of "startp" or where "dirc" is found ('/', '?', etc).
   * Take care of characters with a backslash in front of it.
   * Skip strings inside [ and ].
   * When "newp" is not NULL and "dirc" is '?', make an allocated copy of the
   * expression and change "\?" to "?".  If "*newp" is not NULL the expression
   * is changed in-place.
   */
      char_u *
  skip_regexp(
      char_u	*startp,
      int		dirc,
      int		magic,
      char_u	**newp)
  {
      int		mymagic;
      char_u	*p = startp;
  
      if (magic)
  	mymagic = MAGIC_ON;
      else
  	mymagic = MAGIC_OFF;
      get_cpo_flags();
  
      for (; p[0] != NUL; mb_ptr_adv(p))
      {
  	if (p[0] == dirc)	/* found end of regexp */
  	    break;
  	if ((p[0] == '[' && mymagic >= MAGIC_ON)
  		|| (p[0] == '\\' && p[1] == '[' && mymagic <= MAGIC_OFF))
  	{
  	    p = skip_anyof(p + 1);
  	    if (p[0] == NUL)
  		break;
  	}
  	else if (p[0] == '\\' && p[1] != NUL)
  	{
  	    if (dirc == '?' && newp != NULL && p[1] == '?')
  	    {
  		/* change "\?" to "?", make a copy first. */
  		if (*newp == NULL)
  		{
  		    *newp = vim_strsave(startp);
  		    if (*newp != NULL)
  			p = *newp + (p - startp);
  		}
  		if (*newp != NULL)
  		    STRMOVE(p, p + 1);
  		else
  		    ++p;
  	    }
  	    else
  		++p;    /* skip next character */
  	    if (*p == 'v')
  		mymagic = MAGIC_ALL;
  	    else if (*p == 'V')
  		mymagic = MAGIC_NONE;
  	}
      }
      return p;
  }
  
  static regprog_T  *bt_regcomp(char_u *expr, int re_flags);
  static void bt_regfree(regprog_T *prog);
  
  /*
   * bt_regcomp() - compile a regular expression into internal code for the
   * traditional back track matcher.
   * Returns the program in allocated space.  Returns NULL for an error.
   *
   * We can't allocate space until we know how big the compiled form will be,
   * but we can't compile it (and thus know how big it is) until we've got a
   * place to put the code.  So we cheat:  we compile it twice, once with code
   * generation turned off and size counting turned on, and once "for real".
   * This also means that we don't allocate space until we are sure that the
   * thing really will compile successfully, and we never have to move the
   * code and thus invalidate pointers into it.  (Note that it has to be in
   * one piece because vim_free() must be able to free it all.)
   *
   * Whether upper/lower case is to be ignored is decided when executing the
   * program, it does not matter here.
   *
   * Beware that the optimization-preparation code in here knows about some
   * of the structure of the compiled regexp.
   * "re_flags": RE_MAGIC and/or RE_STRING.
   */
      static regprog_T *
  bt_regcomp(char_u *expr, int re_flags)
  {
      bt_regprog_T    *r;
      char_u	*scan;
      char_u	*longest;
      int		len;
      int		flags;
  
      if (expr == NULL)
  	EMSG_RET_NULL(_(e_null));
  
      init_class_tab();
  
      /*
       * First pass: determine size, legality.
       */
      regcomp_start(expr, re_flags);
      regcode = JUST_CALC_SIZE;
      regc(REGMAGIC);
      if (reg(REG_NOPAREN, &flags) == NULL)
  	return NULL;
  
      /* Allocate space. */
      r = (bt_regprog_T *)lalloc(sizeof(bt_regprog_T) + regsize, TRUE);
      if (r == NULL)
  	return NULL;
  
      /*
       * Second pass: emit code.
       */
      regcomp_start(expr, re_flags);
      regcode = r->program;
      regc(REGMAGIC);
      if (reg(REG_NOPAREN, &flags) == NULL || reg_toolong)
      {
  	vim_free(r);
  	if (reg_toolong)
  	    EMSG_RET_NULL(_("E339: Pattern too long"));
  	return NULL;
      }
  
      /* Dig out information for optimizations. */
      r->regstart = NUL;		/* Worst-case defaults. */
      r->reganch = 0;
      r->regmust = NULL;
      r->regmlen = 0;
      r->regflags = regflags;
      if (flags & HASNL)
  	r->regflags |= RF_HASNL;
      if (flags & HASLOOKBH)
  	r->regflags |= RF_LOOKBH;
  #ifdef FEAT_SYN_HL
      /* Remember whether this pattern has any \z specials in it. */
      r->reghasz = re_has_z;
  #endif
      scan = r->program + 1;	/* First BRANCH. */
      if (OP(regnext(scan)) == END)   /* Only one top-level choice. */
      {
  	scan = OPERAND(scan);
  
  	/* Starting-point info. */
  	if (OP(scan) == BOL || OP(scan) == RE_BOF)
  	{
  	    r->reganch++;
  	    scan = regnext(scan);
  	}
  
  	if (OP(scan) == EXACTLY)
  	{
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  		r->regstart = (*mb_ptr2char)(OPERAND(scan));
  	    else
  #endif
  		r->regstart = *OPERAND(scan);
  	}
  	else if ((OP(scan) == BOW
  		    || OP(scan) == EOW
  		    || OP(scan) == NOTHING
  		    || OP(scan) == MOPEN + 0 || OP(scan) == NOPEN
  		    || OP(scan) == MCLOSE + 0 || OP(scan) == NCLOSE)
  		 && OP(regnext(scan)) == EXACTLY)
  	{
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  		r->regstart = (*mb_ptr2char)(OPERAND(regnext(scan)));
  	    else
  #endif
  		r->regstart = *OPERAND(regnext(scan));
  	}
  
  	/*
  	 * If there's something expensive in the r.e., find the longest
  	 * literal string that must appear and make it the regmust.  Resolve
  	 * ties in favor of later strings, since the regstart check works
  	 * with the beginning of the r.e. and avoiding duplication
  	 * strengthens checking.  Not a strong reason, but sufficient in the
  	 * absence of others.
  	 */
  	/*
  	 * When the r.e. starts with BOW, it is faster to look for a regmust
  	 * first. Used a lot for "#" and "*" commands. (Added by mool).
  	 */
  	if ((flags & SPSTART || OP(scan) == BOW || OP(scan) == EOW)
  							  && !(flags & HASNL))
  	{
  	    longest = NULL;
  	    len = 0;
  	    for (; scan != NULL; scan = regnext(scan))
  		if (OP(scan) == EXACTLY && STRLEN(OPERAND(scan)) >= (size_t)len)
  		{
  		    longest = OPERAND(scan);
  		    len = (int)STRLEN(OPERAND(scan));
  		}
  	    r->regmust = longest;
  	    r->regmlen = len;
  	}
      }
  #ifdef BT_REGEXP_DUMP
      regdump(expr, r);
  #endif
      r->engine = &bt_regengine;
      return (regprog_T *)r;
  }
  
  /*
   * Free a compiled regexp program, returned by bt_regcomp().
   */
      static void
  bt_regfree(regprog_T *prog)
  {
      vim_free(prog);
  }
  
  /*
   * Setup to parse the regexp.  Used once to get the length and once to do it.
   */
      static void
  regcomp_start(
      char_u	*expr,
      int		re_flags)	    /* see vim_regcomp() */
  {
      initchr(expr);
      if (re_flags & RE_MAGIC)
  	reg_magic = MAGIC_ON;
      else
  	reg_magic = MAGIC_OFF;
      reg_string = (re_flags & RE_STRING);
      reg_strict = (re_flags & RE_STRICT);
      get_cpo_flags();
  
      num_complex_braces = 0;
      regnpar = 1;
      vim_memset(had_endbrace, 0, sizeof(had_endbrace));
  #ifdef FEAT_SYN_HL
      regnzpar = 1;
      re_has_z = 0;
  #endif
      regsize = 0L;
      reg_toolong = FALSE;
      regflags = 0;
  #if defined(FEAT_SYN_HL) || defined(PROTO)
      had_eol = FALSE;
  #endif
  }
  
  #if defined(FEAT_SYN_HL) || defined(PROTO)
  /*
   * Check if during the previous call to vim_regcomp the EOL item "$" has been
   * found.  This is messy, but it works fine.
   */
      int
  vim_regcomp_had_eol(void)
  {
      return had_eol;
  }
  #endif
  
  /* variables for parsing reginput */
  static int	at_start;	/* True when on the first character */
  static int	prev_at_start;  /* True when on the second character */
  
  /*
   * Parse regular expression, i.e. main body or parenthesized thing.
   *
   * Caller must absorb opening parenthesis.
   *
   * Combining parenthesis handling with the base level of regular expression
   * is a trifle forced, but the need to tie the tails of the branches to what
   * follows makes it hard to avoid.
   */
      static char_u *
  reg(
      int		paren,	/* REG_NOPAREN, REG_PAREN, REG_NPAREN or REG_ZPAREN */
      int		*flagp)
  {
      char_u	*ret;
      char_u	*br;
      char_u	*ender;
      int		parno = 0;
      int		flags;
  
      *flagp = HASWIDTH;		/* Tentatively. */
  
  #ifdef FEAT_SYN_HL
      if (paren == REG_ZPAREN)
      {
  	/* Make a ZOPEN node. */
  	if (regnzpar >= NSUBEXP)
  	    EMSG_RET_NULL(_("E50: Too many \\z("));
  	parno = regnzpar;
  	regnzpar++;
  	ret = regnode(ZOPEN + parno);
      }
      else
  #endif
  	if (paren == REG_PAREN)
      {
  	/* Make a MOPEN node. */
  	if (regnpar >= NSUBEXP)
  	    EMSG2_RET_NULL(_("E51: Too many %s("), reg_magic == MAGIC_ALL);
  	parno = regnpar;
  	++regnpar;
  	ret = regnode(MOPEN + parno);
      }
      else if (paren == REG_NPAREN)
      {
  	/* Make a NOPEN node. */
  	ret = regnode(NOPEN);
      }
      else
  	ret = NULL;
  
      /* Pick up the branches, linking them together. */
      br = regbranch(&flags);
      if (br == NULL)
  	return NULL;
      if (ret != NULL)
  	regtail(ret, br);	/* [MZ]OPEN -> first. */
      else
  	ret = br;
      /* If one of the branches can be zero-width, the whole thing can.
       * If one of the branches has * at start or matches a line-break, the
       * whole thing can. */
      if (!(flags & HASWIDTH))
  	*flagp &= ~HASWIDTH;
      *flagp |= flags & (SPSTART | HASNL | HASLOOKBH);
      while (peekchr() == Magic('|'))
      {
  	skipchr();
  	br = regbranch(&flags);
  	if (br == NULL || reg_toolong)
  	    return NULL;
  	regtail(ret, br);	/* BRANCH -> BRANCH. */
  	if (!(flags & HASWIDTH))
  	    *flagp &= ~HASWIDTH;
  	*flagp |= flags & (SPSTART | HASNL | HASLOOKBH);
      }
  
      /* Make a closing node, and hook it on the end. */
      ender = regnode(
  #ifdef FEAT_SYN_HL
  	    paren == REG_ZPAREN ? ZCLOSE + parno :
  #endif
  	    paren == REG_PAREN ? MCLOSE + parno :
  	    paren == REG_NPAREN ? NCLOSE : END);
      regtail(ret, ender);
  
      /* Hook the tails of the branches to the closing node. */
      for (br = ret; br != NULL; br = regnext(br))
  	regoptail(br, ender);
  
      /* Check for proper termination. */
      if (paren != REG_NOPAREN && getchr() != Magic(')'))
      {
  #ifdef FEAT_SYN_HL
  	if (paren == REG_ZPAREN)
  	    EMSG_RET_NULL(_("E52: Unmatched \\z("));
  	else
  #endif
  	    if (paren == REG_NPAREN)
  	    EMSG2_RET_NULL(_(e_unmatchedpp), reg_magic == MAGIC_ALL);
  	else
  	    EMSG2_RET_NULL(_(e_unmatchedp), reg_magic == MAGIC_ALL);
      }
      else if (paren == REG_NOPAREN && peekchr() != NUL)
      {
  	if (curchr == Magic(')'))
  	    EMSG2_RET_NULL(_(e_unmatchedpar), reg_magic == MAGIC_ALL);
  	else
  	    EMSG_RET_NULL(_(e_trailing));	/* "Can't happen". */
  	/* NOTREACHED */
      }
      /*
       * Here we set the flag allowing back references to this set of
       * parentheses.
       */
      if (paren == REG_PAREN)
  	had_endbrace[parno] = TRUE;	/* have seen the close paren */
      return ret;
  }
  
  /*
   * Parse one alternative of an | operator.
   * Implements the & operator.
   */
      static char_u *
  regbranch(int *flagp)
  {
      char_u	*ret;
      char_u	*chain = NULL;
      char_u	*latest;
      int		flags;
  
      *flagp = WORST | HASNL;		/* Tentatively. */
  
      ret = regnode(BRANCH);
      for (;;)
      {
  	latest = regconcat(&flags);
  	if (latest == NULL)
  	    return NULL;
  	/* If one of the branches has width, the whole thing has.  If one of
  	 * the branches anchors at start-of-line, the whole thing does.
  	 * If one of the branches uses look-behind, the whole thing does. */
  	*flagp |= flags & (HASWIDTH | SPSTART | HASLOOKBH);
  	/* If one of the branches doesn't match a line-break, the whole thing
  	 * doesn't. */
  	*flagp &= ~HASNL | (flags & HASNL);
  	if (chain != NULL)
  	    regtail(chain, latest);
  	if (peekchr() != Magic('&'))
  	    break;
  	skipchr();
  	regtail(latest, regnode(END)); /* operand ends */
  	if (reg_toolong)
  	    break;
  	reginsert(MATCH, latest);
  	chain = latest;
      }
  
      return ret;
  }
  
  /*
   * Parse one alternative of an | or & operator.
   * Implements the concatenation operator.
   */
      static char_u *
  regconcat(int *flagp)
  {
      char_u	*first = NULL;
      char_u	*chain = NULL;
      char_u	*latest;
      int		flags;
      int		cont = TRUE;
  
      *flagp = WORST;		/* Tentatively. */
  
      while (cont)
      {
  	switch (peekchr())
  	{
  	    case NUL:
  	    case Magic('|'):
  	    case Magic('&'):
  	    case Magic(')'):
  			    cont = FALSE;
  			    break;
  	    case Magic('Z'):
  #ifdef FEAT_MBYTE
  			    regflags |= RF_ICOMBINE;
  #endif
  			    skipchr_keepstart();
  			    break;
  	    case Magic('c'):
  			    regflags |= RF_ICASE;
  			    skipchr_keepstart();
  			    break;
  	    case Magic('C'):
  			    regflags |= RF_NOICASE;
  			    skipchr_keepstart();
  			    break;
  	    case Magic('v'):
  			    reg_magic = MAGIC_ALL;
  			    skipchr_keepstart();
  			    curchr = -1;
  			    break;
  	    case Magic('m'):
  			    reg_magic = MAGIC_ON;
  			    skipchr_keepstart();
  			    curchr = -1;
  			    break;
  	    case Magic('M'):
  			    reg_magic = MAGIC_OFF;
  			    skipchr_keepstart();
  			    curchr = -1;
  			    break;
  	    case Magic('V'):
  			    reg_magic = MAGIC_NONE;
  			    skipchr_keepstart();
  			    curchr = -1;
  			    break;
  	    default:
  			    latest = regpiece(&flags);
  			    if (latest == NULL || reg_toolong)
  				return NULL;
  			    *flagp |= flags & (HASWIDTH | HASNL | HASLOOKBH);
  			    if (chain == NULL)	/* First piece. */
  				*flagp |= flags & SPSTART;
  			    else
  				regtail(chain, latest);
  			    chain = latest;
  			    if (first == NULL)
  				first = latest;
  			    break;
  	}
      }
      if (first == NULL)		/* Loop ran zero times. */
  	first = regnode(NOTHING);
      return first;
  }
  
  /*
   * Parse something followed by possible [*+=].
   *
   * Note that the branching code sequences used for = and the general cases
   * of * and + are somewhat optimized:  they use the same NOTHING node as
   * both the endmarker for their branch list and the body of the last branch.
   * It might seem that this node could be dispensed with entirely, but the
   * endmarker role is not redundant.
   */
      static char_u *
  regpiece(int *flagp)
  {
      char_u	    *ret;
      int		    op;
      char_u	    *next;
      int		    flags;
      long	    minval;
      long	    maxval;
  
      ret = regatom(&flags);
      if (ret == NULL)
  	return NULL;
  
      op = peekchr();
      if (re_multi_type(op) == NOT_MULTI)
      {
  	*flagp = flags;
  	return ret;
      }
      /* default flags */
      *flagp = (WORST | SPSTART | (flags & (HASNL | HASLOOKBH)));
  
      skipchr();
      switch (op)
      {
  	case Magic('*'):
  	    if (flags & SIMPLE)
  		reginsert(STAR, ret);
  	    else
  	    {
  		/* Emit x* as (x&|), where & means "self". */
  		reginsert(BRANCH, ret); /* Either x */
  		regoptail(ret, regnode(BACK));	/* and loop */
  		regoptail(ret, ret);	/* back */
  		regtail(ret, regnode(BRANCH));	/* or */
  		regtail(ret, regnode(NOTHING)); /* null. */
  	    }
  	    break;
  
  	case Magic('+'):
  	    if (flags & SIMPLE)
  		reginsert(PLUS, ret);
  	    else
  	    {
  		/* Emit x+ as x(&|), where & means "self". */
  		next = regnode(BRANCH); /* Either */
  		regtail(ret, next);
  		regtail(regnode(BACK), ret);	/* loop back */
  		regtail(next, regnode(BRANCH)); /* or */
  		regtail(ret, regnode(NOTHING)); /* null. */
  	    }
  	    *flagp = (WORST | HASWIDTH | (flags & (HASNL | HASLOOKBH)));
  	    break;
  
  	case Magic('@'):
  	    {
  		int	lop = END;
  		int	nr;
  
  		nr = getdecchrs();
  		switch (no_Magic(getchr()))
  		{
  		    case '=': lop = MATCH; break;		  /* \@= */
  		    case '!': lop = NOMATCH; break;		  /* \@! */
  		    case '>': lop = SUBPAT; break;		  /* \@> */
  		    case '<': switch (no_Magic(getchr()))
  			      {
  				  case '=': lop = BEHIND; break;   /* \@<= */
  				  case '!': lop = NOBEHIND; break; /* \@<! */
  			      }
  		}
  		if (lop == END)
  		    EMSG2_RET_NULL(_("E59: invalid character after %s@"),
  						      reg_magic == MAGIC_ALL);
  		/* Look behind must match with behind_pos. */
  		if (lop == BEHIND || lop == NOBEHIND)
  		{
  		    regtail(ret, regnode(BHPOS));
  		    *flagp |= HASLOOKBH;
  		}
  		regtail(ret, regnode(END)); /* operand ends */
  		if (lop == BEHIND || lop == NOBEHIND)
  		{
  		    if (nr < 0)
  			nr = 0; /* no limit is same as zero limit */
  		    reginsert_nr(lop, nr, ret);
  		}
  		else
  		    reginsert(lop, ret);
  		break;
  	    }
  
  	case Magic('?'):
  	case Magic('='):
  	    /* Emit x= as (x|) */
  	    reginsert(BRANCH, ret);		/* Either x */
  	    regtail(ret, regnode(BRANCH));	/* or */
  	    next = regnode(NOTHING);		/* null. */
  	    regtail(ret, next);
  	    regoptail(ret, next);
  	    break;
  
  	case Magic('{'):
  	    if (!read_limits(&minval, &maxval))
  		return NULL;
  	    if (flags & SIMPLE)
  	    {
  		reginsert(BRACE_SIMPLE, ret);
  		reginsert_limits(BRACE_LIMITS, minval, maxval, ret);
  	    }
  	    else
  	    {
  		if (num_complex_braces >= 10)
  		    EMSG2_RET_NULL(_("E60: Too many complex %s{...}s"),
  						      reg_magic == MAGIC_ALL);
  		reginsert(BRACE_COMPLEX + num_complex_braces, ret);
  		regoptail(ret, regnode(BACK));
  		regoptail(ret, ret);
  		reginsert_limits(BRACE_LIMITS, minval, maxval, ret);
  		++num_complex_braces;
  	    }
  	    if (minval > 0 && maxval > 0)
  		*flagp = (HASWIDTH | (flags & (HASNL | HASLOOKBH)));
  	    break;
      }
      if (re_multi_type(peekchr()) != NOT_MULTI)
      {
  	/* Can't have a multi follow a multi. */
  	if (peekchr() == Magic('*'))
  	    sprintf((char *)IObuff, _("E61: Nested %s*"),
  					    reg_magic >= MAGIC_ON ? "" : "\\");
  	else
  	    sprintf((char *)IObuff, _("E62: Nested %s%c"),
  		reg_magic == MAGIC_ALL ? "" : "\\", no_Magic(peekchr()));
  	EMSG_RET_NULL(IObuff);
      }
  
      return ret;
  }
  
  /* When making changes to classchars also change nfa_classcodes. */
  static char_u	*classchars = (char_u *)".iIkKfFpPsSdDxXoOwWhHaAlLuU";
  static int	classcodes[] = {
      ANY, IDENT, SIDENT, KWORD, SKWORD,
      FNAME, SFNAME, PRINT, SPRINT,
      WHITE, NWHITE, DIGIT, NDIGIT,
      HEX, NHEX, OCTAL, NOCTAL,
      WORD, NWORD, HEAD, NHEAD,
      ALPHA, NALPHA, LOWER, NLOWER,
      UPPER, NUPPER
  };
  
  /*
   * Parse the lowest level.
   *
   * Optimization:  gobbles an entire sequence of ordinary characters so that
   * it can turn them into a single node, which is smaller to store and
   * faster to run.  Don't do this when one_exactly is set.
   */
      static char_u *
  regatom(int *flagp)
  {
      char_u	    *ret;
      int		    flags;
      int		    c;
      char_u	    *p;
      int		    extra = 0;
      int		    save_prev_at_start = prev_at_start;
  
      *flagp = WORST;		/* Tentatively. */
  
      c = getchr();
      switch (c)
      {
        case Magic('^'):
  	ret = regnode(BOL);
  	break;
  
        case Magic('$'):
  	ret = regnode(EOL);
  #if defined(FEAT_SYN_HL) || defined(PROTO)
  	had_eol = TRUE;
  #endif
  	break;
  
        case Magic('<'):
  	ret = regnode(BOW);
  	break;
  
        case Magic('>'):
  	ret = regnode(EOW);
  	break;
  
        case Magic('_'):
  	c = no_Magic(getchr());
  	if (c == '^')		/* "\_^" is start-of-line */
  	{
  	    ret = regnode(BOL);
  	    break;
  	}
  	if (c == '$')		/* "\_$" is end-of-line */
  	{
  	    ret = regnode(EOL);
  #if defined(FEAT_SYN_HL) || defined(PROTO)
  	    had_eol = TRUE;
  #endif
  	    break;
  	}
  
  	extra = ADD_NL;
  	*flagp |= HASNL;
  
  	/* "\_[" is character range plus newline */
  	if (c == '[')
  	    goto collection;
  
  	/* "\_x" is character class plus newline */
  	/*FALLTHROUGH*/
  
  	/*
  	 * Character classes.
  	 */
        case Magic('.'):
        case Magic('i'):
        case Magic('I'):
        case Magic('k'):
        case Magic('K'):
        case Magic('f'):
        case Magic('F'):
        case Magic('p'):
        case Magic('P'):
        case Magic('s'):
        case Magic('S'):
        case Magic('d'):
        case Magic('D'):
        case Magic('x'):
        case Magic('X'):
        case Magic('o'):
        case Magic('O'):
        case Magic('w'):
        case Magic('W'):
        case Magic('h'):
        case Magic('H'):
        case Magic('a'):
        case Magic('A'):
        case Magic('l'):
        case Magic('L'):
        case Magic('u'):
        case Magic('U'):
  	p = vim_strchr(classchars, no_Magic(c));
  	if (p == NULL)
  	    EMSG_RET_NULL(_("E63: invalid use of \\_"));
  #ifdef FEAT_MBYTE
  	/* When '.' is followed by a composing char ignore the dot, so that
  	 * the composing char is matched here. */
  	if (enc_utf8 && c == Magic('.') && utf_iscomposing(peekchr()))
  	{
  	    c = getchr();
  	    goto do_multibyte;
  	}
  #endif
  	ret = regnode(classcodes[p - classchars] + extra);
  	*flagp |= HASWIDTH | SIMPLE;
  	break;
  
        case Magic('n'):
  	if (reg_string)
  	{
  	    /* In a string "\n" matches a newline character. */
  	    ret = regnode(EXACTLY);
  	    regc(NL);
  	    regc(NUL);
  	    *flagp |= HASWIDTH | SIMPLE;
  	}
  	else
  	{
  	    /* In buffer text "\n" matches the end of a line. */
  	    ret = regnode(NEWL);
  	    *flagp |= HASWIDTH | HASNL;
  	}
  	break;
  
        case Magic('('):
  	if (one_exactly)
  	    EMSG_ONE_RET_NULL;
  	ret = reg(REG_PAREN, &flags);
  	if (ret == NULL)
  	    return NULL;
  	*flagp |= flags & (HASWIDTH | SPSTART | HASNL | HASLOOKBH);
  	break;
  
        case NUL:
        case Magic('|'):
        case Magic('&'):
        case Magic(')'):
  	if (one_exactly)
  	    EMSG_ONE_RET_NULL;
  	EMSG_RET_NULL(_(e_internal));	/* Supposed to be caught earlier. */
  	/* NOTREACHED */
  
        case Magic('='):
        case Magic('?'):
        case Magic('+'):
        case Magic('@'):
        case Magic('{'):
        case Magic('*'):
  	c = no_Magic(c);
  	sprintf((char *)IObuff, _("E64: %s%c follows nothing"),
  		(c == '*' ? reg_magic >= MAGIC_ON : reg_magic == MAGIC_ALL)
  		? "" : "\\", c);
  	EMSG_RET_NULL(IObuff);
  	/* NOTREACHED */
  
        case Magic('~'):		/* previous substitute pattern */
  	    if (reg_prev_sub != NULL)
  	    {
  		char_u	    *lp;
  
  		ret = regnode(EXACTLY);
  		lp = reg_prev_sub;
  		while (*lp != NUL)
  		    regc(*lp++);
  		regc(NUL);
  		if (*reg_prev_sub != NUL)
  		{
  		    *flagp |= HASWIDTH;
  		    if ((lp - reg_prev_sub) == 1)
  			*flagp |= SIMPLE;
  		}
  	    }
  	    else
  		EMSG_RET_NULL(_(e_nopresub));
  	    break;
  
        case Magic('1'):
        case Magic('2'):
        case Magic('3'):
        case Magic('4'):
        case Magic('5'):
        case Magic('6'):
        case Magic('7'):
        case Magic('8'):
        case Magic('9'):
  	    {
  		int		    refnum;
  
  		refnum = c - Magic('0');
  		/*
  		 * Check if the back reference is legal. We must have seen the
  		 * close brace.
  		 * TODO: Should also check that we don't refer to something
  		 * that is repeated (+*=): what instance of the repetition
  		 * should we match?
  		 */
  		if (!had_endbrace[refnum])
  		{
  		    /* Trick: check if "@<=" or "@<!" follows, in which case
  		     * the \1 can appear before the referenced match. */
  		    for (p = regparse; *p != NUL; ++p)
  			if (p[0] == '@' && p[1] == '<'
  					      && (p[2] == '!' || p[2] == '='))
  			    break;
  		    if (*p == NUL)
  			EMSG_RET_NULL(_("E65: Illegal back reference"));
  		}
  		ret = regnode(BACKREF + refnum);
  	    }
  	    break;
  
        case Magic('z'):
  	{
  	    c = no_Magic(getchr());
  	    switch (c)
  	    {
  #ifdef FEAT_SYN_HL
  		case '(': if (reg_do_extmatch != REX_SET)
  			      EMSG_RET_NULL(_(e_z_not_allowed));
  			  if (one_exactly)
  			      EMSG_ONE_RET_NULL;
  			  ret = reg(REG_ZPAREN, &flags);
  			  if (ret == NULL)
  			      return NULL;
  			  *flagp |= flags & (HASWIDTH|SPSTART|HASNL|HASLOOKBH);
  			  re_has_z = REX_SET;
  			  break;
  
  		case '1':
  		case '2':
  		case '3':
  		case '4':
  		case '5':
  		case '6':
  		case '7':
  		case '8':
  		case '9': if (reg_do_extmatch != REX_USE)
  			      EMSG_RET_NULL(_(e_z1_not_allowed));
  			  ret = regnode(ZREF + c - '0');
  			  re_has_z = REX_USE;
  			  break;
  #endif
  
  		case 's': ret = regnode(MOPEN + 0);
  			  if (re_mult_next("\\zs") == FAIL)
  			      return NULL;
  			  break;
  
  		case 'e': ret = regnode(MCLOSE + 0);
  			  if (re_mult_next("\\ze") == FAIL)
  			      return NULL;
  			  break;
  
  		default:  EMSG_RET_NULL(_("E68: Invalid character after \\z"));
  	    }
  	}
  	break;
  
        case Magic('%'):
  	{
  	    c = no_Magic(getchr());
  	    switch (c)
  	    {
  		/* () without a back reference */
  		case '(':
  		    if (one_exactly)
  			EMSG_ONE_RET_NULL;
  		    ret = reg(REG_NPAREN, &flags);
  		    if (ret == NULL)
  			return NULL;
  		    *flagp |= flags & (HASWIDTH | SPSTART | HASNL | HASLOOKBH);
  		    break;
  
  		/* Catch \%^ and \%$ regardless of where they appear in the
  		 * pattern -- regardless of whether or not it makes sense. */
  		case '^':
  		    ret = regnode(RE_BOF);
  		    break;
  
  		case '$':
  		    ret = regnode(RE_EOF);
  		    break;
  
  		case '#':
  		    ret = regnode(CURSOR);
  		    break;
  
  		case 'V':
  		    ret = regnode(RE_VISUAL);
  		    break;
  
  		case 'C':
  		    ret = regnode(RE_COMPOSING);
  		    break;
  
  		/* \%[abc]: Emit as a list of branches, all ending at the last
  		 * branch which matches nothing. */
  		case '[':
  			  if (one_exactly)	/* doesn't nest */
  			      EMSG_ONE_RET_NULL;
  			  {
  			      char_u	*lastbranch;
  			      char_u	*lastnode = NULL;
  			      char_u	*br;
  
  			      ret = NULL;
  			      while ((c = getchr()) != ']')
  			      {
  				  if (c == NUL)
  				      EMSG2_RET_NULL(_(e_missing_sb),
  						      reg_magic == MAGIC_ALL);
  				  br = regnode(BRANCH);
  				  if (ret == NULL)
  				      ret = br;
  				  else
  				      regtail(lastnode, br);
  
  				  ungetchr();
  				  one_exactly = TRUE;
  				  lastnode = regatom(flagp);
  				  one_exactly = FALSE;
  				  if (lastnode == NULL)
  				      return NULL;
  			      }
  			      if (ret == NULL)
  				  EMSG2_RET_NULL(_(e_empty_sb),
  						      reg_magic == MAGIC_ALL);
  			      lastbranch = regnode(BRANCH);
  			      br = regnode(NOTHING);
  			      if (ret != JUST_CALC_SIZE)
  			      {
  				  regtail(lastnode, br);
  				  regtail(lastbranch, br);
  				  /* connect all branches to the NOTHING
  				   * branch at the end */
  				  for (br = ret; br != lastnode; )
  				  {
  				      if (OP(br) == BRANCH)
  				      {
  					  regtail(br, lastbranch);
  					  br = OPERAND(br);
  				      }
  				      else
  					  br = regnext(br);
  				  }
  			      }
  			      *flagp &= ~(HASWIDTH | SIMPLE);
  			      break;
  			  }
  
  		case 'd':   /* %d123 decimal */
  		case 'o':   /* %o123 octal */
  		case 'x':   /* %xab hex 2 */
  		case 'u':   /* %uabcd hex 4 */
  		case 'U':   /* %U1234abcd hex 8 */
  			  {
  			      int i;
  
  			      switch (c)
  			      {
  				  case 'd': i = getdecchrs(); break;
  				  case 'o': i = getoctchrs(); break;
  				  case 'x': i = gethexchrs(2); break;
  				  case 'u': i = gethexchrs(4); break;
  				  case 'U': i = gethexchrs(8); break;
  				  default:  i = -1; break;
  			      }
  
  			      if (i < 0)
  				  EMSG2_RET_NULL(
  					_("E678: Invalid character after %s%%[dxouU]"),
  					reg_magic == MAGIC_ALL);
  #ifdef FEAT_MBYTE
  			      if (use_multibytecode(i))
  				  ret = regnode(MULTIBYTECODE);
  			      else
  #endif
  				  ret = regnode(EXACTLY);
  			      if (i == 0)
  				  regc(0x0a);
  			      else
  #ifdef FEAT_MBYTE
  				  regmbc(i);
  #else
  				  regc(i);
  #endif
  			      regc(NUL);
  			      *flagp |= HASWIDTH;
  			      break;
  			  }
  
  		default:
  			  if (VIM_ISDIGIT(c) || c == '<' || c == '>'
  								 || c == '\'')
  			  {
  			      long_u	n = 0;
  			      int	cmp;
  
  			      cmp = c;
  			      if (cmp == '<' || cmp == '>')
  				  c = getchr();
  			      while (VIM_ISDIGIT(c))
  			      {
  				  n = n * 10 + (c - '0');
  				  c = getchr();
  			      }
  			      if (c == '\'' && n == 0)
  			      {
  				  /* "\%'m", "\%<'m" and "\%>'m": Mark */
  				  c = getchr();
  				  ret = regnode(RE_MARK);
  				  if (ret == JUST_CALC_SIZE)
  				      regsize += 2;
  				  else
  				  {
  				      *regcode++ = c;
  				      *regcode++ = cmp;
  				  }
  				  break;
  			      }
  			      else if (c == 'l' || c == 'c' || c == 'v')
  			      {
  				  if (c == 'l')
  				  {
  				      ret = regnode(RE_LNUM);
  				      if (save_prev_at_start)
  					  at_start = TRUE;
  				  }
  				  else if (c == 'c')
  				      ret = regnode(RE_COL);
  				  else
  				      ret = regnode(RE_VCOL);
  				  if (ret == JUST_CALC_SIZE)
  				      regsize += 5;
  				  else
  				  {
  				      /* put the number and the optional
  				       * comparator after the opcode */
  				      regcode = re_put_long(regcode, n);
  				      *regcode++ = cmp;
  				  }
  				  break;
  			      }
  			  }
  
  			  EMSG2_RET_NULL(_("E71: Invalid character after %s%%"),
  						      reg_magic == MAGIC_ALL);
  	    }
  	}
  	break;
  
        case Magic('['):
  collection:
  	{
  	    char_u	*lp;
  
  	    /*
  	     * If there is no matching ']', we assume the '[' is a normal
  	     * character.  This makes 'incsearch' and ":help [" work.
  	     */
  	    lp = skip_anyof(regparse);
  	    if (*lp == ']')	/* there is a matching ']' */
  	    {
  		int	startc = -1;	/* > 0 when next '-' is a range */
  		int	endc;
  
  		/*
  		 * In a character class, different parsing rules apply.
  		 * Not even \ is special anymore, nothing is.
  		 */
  		if (*regparse == '^')	    /* Complement of range. */
  		{
  		    ret = regnode(ANYBUT + extra);
  		    regparse++;
  		}
  		else
  		    ret = regnode(ANYOF + extra);
  
  		/* At the start ']' and '-' mean the literal character. */
  		if (*regparse == ']' || *regparse == '-')
  		{
  		    startc = *regparse;
  		    regc(*regparse++);
  		}
  
  		while (*regparse != NUL && *regparse != ']')
  		{
  		    if (*regparse == '-')
  		    {
  			++regparse;
  			/* The '-' is not used for a range at the end and
  			 * after or before a '\n'. */
  			if (*regparse == ']' || *regparse == NUL
  				|| startc == -1
  				|| (regparse[0] == '\\' && regparse[1] == 'n'))
  			{
  			    regc('-');
  			    startc = '-';	/* [--x] is a range */
  			}
  			else
  			{
  			    /* Also accept "a-[.z.]" */
  			    endc = 0;
  			    if (*regparse == '[')
  				endc = get_coll_element(&regparse);
  			    if (endc == 0)
  			    {
  #ifdef FEAT_MBYTE
  				if (has_mbyte)
  				    endc = mb_ptr2char_adv(&regparse);
  				else
  #endif
  				    endc = *regparse++;
  			    }
  
  			    /* Handle \o40, \x20 and \u20AC style sequences */
  			    if (endc == '\\' && !reg_cpo_lit && !reg_cpo_bsl)
  				endc = coll_get_char();
  
  			    if (startc > endc)
  				EMSG_RET_NULL(_(e_invrange));
  #ifdef FEAT_MBYTE
  			    if (has_mbyte && ((*mb_char2len)(startc) > 1
  						 || (*mb_char2len)(endc) > 1))
  			    {
  				/* Limit to a range of 256 chars */
  				if (endc > startc + 256)
  				    EMSG_RET_NULL(_(e_invrange));
  				while (++startc <= endc)
  				    regmbc(startc);
  			    }
  			    else
  #endif
  			    {
  #ifdef EBCDIC
  				int	alpha_only = FALSE;
  
  				/* for alphabetical range skip the gaps
  				 * 'i'-'j', 'r'-'s', 'I'-'J' and 'R'-'S'.  */
  				if (isalpha(startc) && isalpha(endc))
  				    alpha_only = TRUE;
  #endif
  				while (++startc <= endc)
  #ifdef EBCDIC
  				    if (!alpha_only || isalpha(startc))
  #endif
  					regc(startc);
  			    }
  			    startc = -1;
  			}
  		    }
  		    /*
  		     * Only "\]", "\^", "\]" and "\\" are special in Vi.  Vim
  		     * accepts "\t", "\e", etc., but only when the 'l' flag in
  		     * 'cpoptions' is not included.
  		     * Posix doesn't recognize backslash at all.
  		     */
  		    else if (*regparse == '\\'
  			    && !reg_cpo_bsl
  			    && (vim_strchr(REGEXP_INRANGE, regparse[1]) != NULL
  				|| (!reg_cpo_lit
  				    && vim_strchr(REGEXP_ABBR,
  						       regparse[1]) != NULL)))
  		    {
  			regparse++;
  			if (*regparse == 'n')
  			{
  			    /* '\n' in range: also match NL */
  			    if (ret != JUST_CALC_SIZE)
  			    {
  				/* Using \n inside [^] does not change what
  				 * matches. "[^\n]" is the same as ".". */
  				if (*ret == ANYOF)
  				{
  				    *ret = ANYOF + ADD_NL;
  				    *flagp |= HASNL;
  				}
  				/* else: must have had a \n already */
  			    }
  			    regparse++;
  			    startc = -1;
  			}
  			else if (*regparse == 'd'
  				|| *regparse == 'o'
  				|| *regparse == 'x'
  				|| *regparse == 'u'
  				|| *regparse == 'U')
  			{
  			    startc = coll_get_char();
  			    if (startc == 0)
  				regc(0x0a);
  			    else
  #ifdef FEAT_MBYTE
  				regmbc(startc);
  #else
  				regc(startc);
  #endif
  			}
  			else
  			{
  			    startc = backslash_trans(*regparse++);
  			    regc(startc);
  			}
  		    }
  		    else if (*regparse == '[')
  		    {
  			int c_class;
  			int cu;
  
  			c_class = get_char_class(&regparse);
  			startc = -1;
  			/* Characters assumed to be 8 bits! */
  			switch (c_class)
  			{
  			    case CLASS_NONE:
  				c_class = get_equi_class(&regparse);
  				if (c_class != 0)
  				{
  				    /* produce equivalence class */
  				    reg_equi_class(c_class);
  				}
  				else if ((c_class =
  					    get_coll_element(&regparse)) != 0)
  				{
  				    /* produce a collating element */
  				    regmbc(c_class);
  				}
  				else
  				{
  				    /* literal '[', allow [[-x] as a range */
  				    startc = *regparse++;
  				    regc(startc);
  				}
  				break;
  			    case CLASS_ALNUM:
  				for (cu = 1; cu <= 255; cu++)
  				    if (isalnum(cu))
  					regc(cu);
  				break;
  			    case CLASS_ALPHA:
  				for (cu = 1; cu <= 255; cu++)
  				    if (isalpha(cu))
  					regc(cu);
  				break;
  			    case CLASS_BLANK:
  				regc(' ');
  				regc('\t');
  				break;
  			    case CLASS_CNTRL:
  				for (cu = 1; cu <= 255; cu++)
  				    if (iscntrl(cu))
  					regc(cu);
  				break;
  			    case CLASS_DIGIT:
  				for (cu = 1; cu <= 255; cu++)
  				    if (VIM_ISDIGIT(cu))
  					regc(cu);
  				break;
  			    case CLASS_GRAPH:
  				for (cu = 1; cu <= 255; cu++)
  				    if (isgraph(cu))
  					regc(cu);
  				break;
  			    case CLASS_LOWER:
  				for (cu = 1; cu <= 255; cu++)
  				    if (MB_ISLOWER(cu))
  					regc(cu);
  				break;
  			    case CLASS_PRINT:
  				for (cu = 1; cu <= 255; cu++)
  				    if (vim_isprintc(cu))
  					regc(cu);
  				break;
  			    case CLASS_PUNCT:
  				for (cu = 1; cu <= 255; cu++)
  				    if (ispunct(cu))
  					regc(cu);
  				break;
  			    case CLASS_SPACE:
  				for (cu = 9; cu <= 13; cu++)
  				    regc(cu);
  				regc(' ');
  				break;
  			    case CLASS_UPPER:
  				for (cu = 1; cu <= 255; cu++)
  				    if (MB_ISUPPER(cu))
  					regc(cu);
  				break;
  			    case CLASS_XDIGIT:
  				for (cu = 1; cu <= 255; cu++)
  				    if (vim_isxdigit(cu))
  					regc(cu);
  				break;
  			    case CLASS_TAB:
  				regc('\t');
  				break;
  			    case CLASS_RETURN:
  				regc('\r');
  				break;
  			    case CLASS_BACKSPACE:
  				regc('\b');
  				break;
  			    case CLASS_ESCAPE:
  				regc('\033');
  				break;
  			}
  		    }
  		    else
  		    {
  #ifdef FEAT_MBYTE
  			if (has_mbyte)
  			{
  			    int	len;
  
  			    /* produce a multibyte character, including any
  			     * following composing characters */
  			    startc = mb_ptr2char(regparse);
  			    len = (*mb_ptr2len)(regparse);
  			    if (enc_utf8 && utf_char2len(startc) != len)
  				startc = -1;	/* composing chars */
  			    while (--len >= 0)
  				regc(*regparse++);
  			}
  			else
  #endif
  			{
  			    startc = *regparse++;
  			    regc(startc);
  			}
  		    }
  		}
  		regc(NUL);
  		prevchr_len = 1;	/* last char was the ']' */
  		if (*regparse != ']')
  		    EMSG_RET_NULL(_(e_toomsbra));	/* Cannot happen? */
  		skipchr();	    /* let's be friends with the lexer again */
  		*flagp |= HASWIDTH | SIMPLE;
  		break;
  	    }
  	    else if (reg_strict)
  		EMSG2_RET_NULL(_(e_missingbracket), reg_magic > MAGIC_OFF);
  	}
  	/* FALLTHROUGH */
  
        default:
  	{
  	    int		len;
  
  #ifdef FEAT_MBYTE
  	    /* A multi-byte character is handled as a separate atom if it's
  	     * before a multi and when it's a composing char. */
  	    if (use_multibytecode(c))
  	    {
  do_multibyte:
  		ret = regnode(MULTIBYTECODE);
  		regmbc(c);
  		*flagp |= HASWIDTH | SIMPLE;
  		break;
  	    }
  #endif
  
  	    ret = regnode(EXACTLY);
  
  	    /*
  	     * Append characters as long as:
  	     * - there is no following multi, we then need the character in
  	     *   front of it as a single character operand
  	     * - not running into a Magic character
  	     * - "one_exactly" is not set
  	     * But always emit at least one character.  Might be a Multi,
  	     * e.g., a "[" without matching "]".
  	     */
  	    for (len = 0; c != NUL && (len == 0
  			|| (re_multi_type(peekchr()) == NOT_MULTI
  			    && !one_exactly
  			    && !is_Magic(c))); ++len)
  	    {
  		c = no_Magic(c);
  #ifdef FEAT_MBYTE
  		if (has_mbyte)
  		{
  		    regmbc(c);
  		    if (enc_utf8)
  		    {
  			int	l;
  
  			/* Need to get composing character too. */
  			for (;;)
  			{
  			    l = utf_ptr2len(regparse);
  			    if (!UTF_COMPOSINGLIKE(regparse, regparse + l))
  				break;
  			    regmbc(utf_ptr2char(regparse));
  			    skipchr();
  			}
  		    }
  		}
  		else
  #endif
  		    regc(c);
  		c = getchr();
  	    }
  	    ungetchr();
  
  	    regc(NUL);
  	    *flagp |= HASWIDTH;
  	    if (len == 1)
  		*flagp |= SIMPLE;
  	}
  	break;
      }
  
      return ret;
  }
  
  #ifdef FEAT_MBYTE
  /*
   * Return TRUE if MULTIBYTECODE should be used instead of EXACTLY for
   * character "c".
   */
      static int
  use_multibytecode(int c)
  {
      return has_mbyte && (*mb_char2len)(c) > 1
  		     && (re_multi_type(peekchr()) != NOT_MULTI
  			     || (enc_utf8 && utf_iscomposing(c)));
  }
  #endif
  
  /*
   * Emit a node.
   * Return pointer to generated code.
   */
      static char_u *
  regnode(int op)
  {
      char_u  *ret;
  
      ret = regcode;
      if (ret == JUST_CALC_SIZE)
  	regsize += 3;
      else
      {
  	*regcode++ = op;
  	*regcode++ = NUL;		/* Null "next" pointer. */
  	*regcode++ = NUL;
      }
      return ret;
  }
  
  /*
   * Emit (if appropriate) a byte of code
   */
      static void
  regc(int b)
  {
      if (regcode == JUST_CALC_SIZE)
  	regsize++;
      else
  	*regcode++ = b;
  }
  
  #ifdef FEAT_MBYTE
  /*
   * Emit (if appropriate) a multi-byte character of code
   */
      static void
  regmbc(int c)
  {
      if (!has_mbyte && c > 0xff)
  	return;
      if (regcode == JUST_CALC_SIZE)
  	regsize += (*mb_char2len)(c);
      else
  	regcode += (*mb_char2bytes)(c, regcode);
  }
  #endif
  
  /*
   * Insert an operator in front of already-emitted operand
   *
   * Means relocating the operand.
   */
      static void
  reginsert(int op, char_u *opnd)
  {
      char_u	*src;
      char_u	*dst;
      char_u	*place;
  
      if (regcode == JUST_CALC_SIZE)
      {
  	regsize += 3;
  	return;
      }
      src = regcode;
      regcode += 3;
      dst = regcode;
      while (src > opnd)
  	*--dst = *--src;
  
      place = opnd;		/* Op node, where operand used to be. */
      *place++ = op;
      *place++ = NUL;
      *place = NUL;
  }
  
  /*
   * Insert an operator in front of already-emitted operand.
   * Add a number to the operator.
   */
      static void
  reginsert_nr(int op, long val, char_u *opnd)
  {
      char_u	*src;
      char_u	*dst;
      char_u	*place;
  
      if (regcode == JUST_CALC_SIZE)
      {
  	regsize += 7;
  	return;
      }
      src = regcode;
      regcode += 7;
      dst = regcode;
      while (src > opnd)
  	*--dst = *--src;
  
      place = opnd;		/* Op node, where operand used to be. */
      *place++ = op;
      *place++ = NUL;
      *place++ = NUL;
      place = re_put_long(place, (long_u)val);
  }
  
  /*
   * Insert an operator in front of already-emitted operand.
   * The operator has the given limit values as operands.  Also set next pointer.
   *
   * Means relocating the operand.
   */
      static void
  reginsert_limits(
      int		op,
      long	minval,
      long	maxval,
      char_u	*opnd)
  {
      char_u	*src;
      char_u	*dst;
      char_u	*place;
  
      if (regcode == JUST_CALC_SIZE)
      {
  	regsize += 11;
  	return;
      }
      src = regcode;
      regcode += 11;
      dst = regcode;
      while (src > opnd)
  	*--dst = *--src;
  
      place = opnd;		/* Op node, where operand used to be. */
      *place++ = op;
      *place++ = NUL;
      *place++ = NUL;
      place = re_put_long(place, (long_u)minval);
      place = re_put_long(place, (long_u)maxval);
      regtail(opnd, place);
  }
  
  /*
   * Write a long as four bytes at "p" and return pointer to the next char.
   */
      static char_u *
  re_put_long(char_u *p, long_u val)
  {
      *p++ = (char_u) ((val >> 24) & 0377);
      *p++ = (char_u) ((val >> 16) & 0377);
      *p++ = (char_u) ((val >> 8) & 0377);
      *p++ = (char_u) (val & 0377);
      return p;
  }
  
  /*
   * Set the next-pointer at the end of a node chain.
   */
      static void
  regtail(char_u *p, char_u *val)
  {
      char_u	*scan;
      char_u	*temp;
      int		offset;
  
      if (p == JUST_CALC_SIZE)
  	return;
  
      /* Find last node. */
      scan = p;
      for (;;)
      {
  	temp = regnext(scan);
  	if (temp == NULL)
  	    break;
  	scan = temp;
      }
  
      if (OP(scan) == BACK)
  	offset = (int)(scan - val);
      else
  	offset = (int)(val - scan);
      /* When the offset uses more than 16 bits it can no longer fit in the two
       * bytes available.  Use a global flag to avoid having to check return
       * values in too many places. */
      if (offset > 0xffff)
  	reg_toolong = TRUE;
      else
      {
  	*(scan + 1) = (char_u) (((unsigned)offset >> 8) & 0377);
  	*(scan + 2) = (char_u) (offset & 0377);
      }
  }
  
  /*
   * Like regtail, on item after a BRANCH; nop if none.
   */
      static void
  regoptail(char_u *p, char_u *val)
  {
      /* When op is neither BRANCH nor BRACE_COMPLEX0-9, it is "operandless" */
      if (p == NULL || p == JUST_CALC_SIZE
  	    || (OP(p) != BRANCH
  		&& (OP(p) < BRACE_COMPLEX || OP(p) > BRACE_COMPLEX + 9)))
  	return;
      regtail(OPERAND(p), val);
  }
  
  /*
   * Functions for getting characters from the regexp input.
   */
  /*
   * Start parsing at "str".
   */
      static void
  initchr(char_u *str)
  {
      regparse = str;
      prevchr_len = 0;
      curchr = prevprevchr = prevchr = nextchr = -1;
      at_start = TRUE;
      prev_at_start = FALSE;
  }
  
  /*
   * Save the current parse state, so that it can be restored and parsing
   * starts in the same state again.
   */
      static void
  save_parse_state(parse_state_T *ps)
  {
      ps->regparse = regparse;
      ps->prevchr_len = prevchr_len;
      ps->curchr = curchr;
      ps->prevchr = prevchr;
      ps->prevprevchr = prevprevchr;
      ps->nextchr = nextchr;
      ps->at_start = at_start;
      ps->prev_at_start = prev_at_start;
      ps->regnpar = regnpar;
  }
  
  /*
   * Restore a previously saved parse state.
   */
      static void
  restore_parse_state(parse_state_T *ps)
  {
      regparse = ps->regparse;
      prevchr_len = ps->prevchr_len;
      curchr = ps->curchr;
      prevchr = ps->prevchr;
      prevprevchr = ps->prevprevchr;
      nextchr = ps->nextchr;
      at_start = ps->at_start;
      prev_at_start = ps->prev_at_start;
      regnpar = ps->regnpar;
  }
  
  
  /*
   * Get the next character without advancing.
   */
      static int
  peekchr(void)
  {
      static int	after_slash = FALSE;
  
      if (curchr == -1)
      {
  	switch (curchr = regparse[0])
  	{
  	case '.':
  	case '[':
  	case '~':
  	    /* magic when 'magic' is on */
  	    if (reg_magic >= MAGIC_ON)
  		curchr = Magic(curchr);
  	    break;
  	case '(':
  	case ')':
  	case '{':
  	case '%':
  	case '+':
  	case '=':
  	case '?':
  	case '@':
  	case '!':
  	case '&':
  	case '|':
  	case '<':
  	case '>':
  	case '#':	/* future ext. */
  	case '"':	/* future ext. */
  	case '\'':	/* future ext. */
  	case ',':	/* future ext. */
  	case '-':	/* future ext. */
  	case ':':	/* future ext. */
  	case ';':	/* future ext. */
  	case '`':	/* future ext. */
  	case '/':	/* Can't be used in / command */
  	    /* magic only after "\v" */
  	    if (reg_magic == MAGIC_ALL)
  		curchr = Magic(curchr);
  	    break;
  	case '*':
  	    /* * is not magic as the very first character, eg "?*ptr", when
  	     * after '^', eg "/^*ptr" and when after "\(", "\|", "\&".  But
  	     * "\(\*" is not magic, thus must be magic if "after_slash" */
  	    if (reg_magic >= MAGIC_ON
  		    && !at_start
  		    && !(prev_at_start && prevchr == Magic('^'))
  		    && (after_slash
  			|| (prevchr != Magic('(')
  			    && prevchr != Magic('&')
  			    && prevchr != Magic('|'))))
  		curchr = Magic('*');
  	    break;
  	case '^':
  	    /* '^' is only magic as the very first character and if it's after
  	     * "\(", "\|", "\&' or "\n" */
  	    if (reg_magic >= MAGIC_OFF
  		    && (at_start
  			|| reg_magic == MAGIC_ALL
  			|| prevchr == Magic('(')
  			|| prevchr == Magic('|')
  			|| prevchr == Magic('&')
  			|| prevchr == Magic('n')
  			|| (no_Magic(prevchr) == '('
  			    && prevprevchr == Magic('%'))))
  	    {
  		curchr = Magic('^');
  		at_start = TRUE;
  		prev_at_start = FALSE;
  	    }
  	    break;
  	case '$':
  	    /* '$' is only magic as the very last char and if it's in front of
  	     * either "\|", "\)", "\&", or "\n" */
  	    if (reg_magic >= MAGIC_OFF)
  	    {
  		char_u *p = regparse + 1;
  		int is_magic_all = (reg_magic == MAGIC_ALL);
  
  		/* ignore \c \C \m \M \v \V and \Z after '$' */
  		while (p[0] == '\\' && (p[1] == 'c' || p[1] == 'C'
  				|| p[1] == 'm' || p[1] == 'M'
  				|| p[1] == 'v' || p[1] == 'V' || p[1] == 'Z'))
  		{
  		    if (p[1] == 'v')
  			is_magic_all = TRUE;
  		    else if (p[1] == 'm' || p[1] == 'M' || p[1] == 'V')
  			is_magic_all = FALSE;
  		    p += 2;
  		}
  		if (p[0] == NUL
  			|| (p[0] == '\\'
  			    && (p[1] == '|' || p[1] == '&' || p[1] == ')'
  				|| p[1] == 'n'))
  			|| (is_magic_all
  			       && (p[0] == '|' || p[0] == '&' || p[0] == ')'))
  			|| reg_magic == MAGIC_ALL)
  		    curchr = Magic('$');
  	    }
  	    break;
  	case '\\':
  	    {
  		int c = regparse[1];
  
  		if (c == NUL)
  		    curchr = '\\';	/* trailing '\' */
  		else if (
  #ifdef EBCDIC
  			vim_strchr(META, c)
  #else
  			c <= '~' && META_flags[c]
  #endif
  			)
  		{
  		    /*
  		     * META contains everything that may be magic sometimes,
  		     * except ^ and $ ("\^" and "\$" are only magic after
  		     * "\V").  We now fetch the next character and toggle its
  		     * magicness.  Therefore, \ is so meta-magic that it is
  		     * not in META.
  		     */
  		    curchr = -1;
  		    prev_at_start = at_start;
  		    at_start = FALSE;	/* be able to say "/\*ptr" */
  		    ++regparse;
  		    ++after_slash;
  		    peekchr();
  		    --regparse;
  		    --after_slash;
  		    curchr = toggle_Magic(curchr);
  		}
  		else if (vim_strchr(REGEXP_ABBR, c))
  		{
  		    /*
  		     * Handle abbreviations, like "\t" for TAB -- webb
  		     */
  		    curchr = backslash_trans(c);
  		}
  		else if (reg_magic == MAGIC_NONE && (c == '$' || c == '^'))
  		    curchr = toggle_Magic(c);
  		else
  		{
  		    /*
  		     * Next character can never be (made) magic?
  		     * Then backslashing it won't do anything.
  		     */
  #ifdef FEAT_MBYTE
  		    if (has_mbyte)
  			curchr = (*mb_ptr2char)(regparse + 1);
  		    else
  #endif
  			curchr = c;
  		}
  		break;
  	    }
  
  #ifdef FEAT_MBYTE
  	default:
  	    if (has_mbyte)
  		curchr = (*mb_ptr2char)(regparse);
  #endif
  	}
      }
  
      return curchr;
  }
  
  /*
   * Eat one lexed character.  Do this in a way that we can undo it.
   */
      static void
  skipchr(void)
  {
      /* peekchr() eats a backslash, do the same here */
      if (*regparse == '\\')
  	prevchr_len = 1;
      else
  	prevchr_len = 0;
      if (regparse[prevchr_len] != NUL)
      {
  #ifdef FEAT_MBYTE
  	if (enc_utf8)
  	    /* exclude composing chars that mb_ptr2len does include */
  	    prevchr_len += utf_ptr2len(regparse + prevchr_len);
  	else if (has_mbyte)
  	    prevchr_len += (*mb_ptr2len)(regparse + prevchr_len);
  	else
  #endif
  	    ++prevchr_len;
      }
      regparse += prevchr_len;
      prev_at_start = at_start;
      at_start = FALSE;
      prevprevchr = prevchr;
      prevchr = curchr;
      curchr = nextchr;	    /* use previously unget char, or -1 */
      nextchr = -1;
  }
  
  /*
   * Skip a character while keeping the value of prev_at_start for at_start.
   * prevchr and prevprevchr are also kept.
   */
      static void
  skipchr_keepstart(void)
  {
      int as = prev_at_start;
      int pr = prevchr;
      int prpr = prevprevchr;
  
      skipchr();
      at_start = as;
      prevchr = pr;
      prevprevchr = prpr;
  }
  
  /*
   * Get the next character from the pattern. We know about magic and such, so
   * therefore we need a lexical analyzer.
   */
      static int
  getchr(void)
  {
      int chr = peekchr();
  
      skipchr();
      return chr;
  }
  
  /*
   * put character back.  Works only once!
   */
      static void
  ungetchr(void)
  {
      nextchr = curchr;
      curchr = prevchr;
      prevchr = prevprevchr;
      at_start = prev_at_start;
      prev_at_start = FALSE;
  
      /* Backup regparse, so that it's at the same position as before the
       * getchr(). */
      regparse -= prevchr_len;
  }
  
  /*
   * Get and return the value of the hex string at the current position.
   * Return -1 if there is no valid hex number.
   * The position is updated:
   *     blahblah\%x20asdf
   *	   before-^ ^-after
   * The parameter controls the maximum number of input characters. This will be
   * 2 when reading a \%x20 sequence and 4 when reading a \%u20AC sequence.
   */
      static int
  gethexchrs(int maxinputlen)
  {
      int		nr = 0;
      int		c;
      int		i;
  
      for (i = 0; i < maxinputlen; ++i)
      {
  	c = regparse[0];
  	if (!vim_isxdigit(c))
  	    break;
  	nr <<= 4;
  	nr |= hex2nr(c);
  	++regparse;
      }
  
      if (i == 0)
  	return -1;
      return nr;
  }
  
  /*
   * Get and return the value of the decimal string immediately after the
   * current position. Return -1 for invalid.  Consumes all digits.
   */
      static int
  getdecchrs(void)
  {
      int		nr = 0;
      int		c;
      int		i;
  
      for (i = 0; ; ++i)
      {
  	c = regparse[0];
  	if (c < '0' || c > '9')
  	    break;
  	nr *= 10;
  	nr += c - '0';
  	++regparse;
  	curchr = -1; /* no longer valid */
      }
  
      if (i == 0)
  	return -1;
      return nr;
  }
  
  /*
   * get and return the value of the octal string immediately after the current
   * position. Return -1 for invalid, or 0-255 for valid. Smart enough to handle
   * numbers > 377 correctly (for example, 400 is treated as 40) and doesn't
   * treat 8 or 9 as recognised characters. Position is updated:
   *     blahblah\%o210asdf
   *	   before-^  ^-after
   */
      static int
  getoctchrs(void)
  {
      int		nr = 0;
      int		c;
      int		i;
  
      for (i = 0; i < 3 && nr < 040; ++i)
      {
  	c = regparse[0];
  	if (c < '0' || c > '7')
  	    break;
  	nr <<= 3;
  	nr |= hex2nr(c);
  	++regparse;
      }
  
      if (i == 0)
  	return -1;
      return nr;
  }
  
  /*
   * Get a number after a backslash that is inside [].
   * When nothing is recognized return a backslash.
   */
      static int
  coll_get_char(void)
  {
      int	    nr = -1;
  
      switch (*regparse++)
      {
  	case 'd': nr = getdecchrs(); break;
  	case 'o': nr = getoctchrs(); break;
  	case 'x': nr = gethexchrs(2); break;
  	case 'u': nr = gethexchrs(4); break;
  	case 'U': nr = gethexchrs(8); break;
      }
      if (nr < 0)
      {
  	/* If getting the number fails be backwards compatible: the character
  	 * is a backslash. */
  	--regparse;
  	nr = '\\';
      }
      return nr;
  }
  
  /*
   * read_limits - Read two integers to be taken as a minimum and maximum.
   * If the first character is '-', then the range is reversed.
   * Should end with 'end'.  If minval is missing, zero is default, if maxval is
   * missing, a very big number is the default.
   */
      static int
  read_limits(long *minval, long *maxval)
  {
      int		reverse = FALSE;
      char_u	*first_char;
      long	tmp;
  
      if (*regparse == '-')
      {
  	/* Starts with '-', so reverse the range later */
  	regparse++;
  	reverse = TRUE;
      }
      first_char = regparse;
      *minval = getdigits(&regparse);
      if (*regparse == ',')	    /* There is a comma */
      {
  	if (vim_isdigit(*++regparse))
  	    *maxval = getdigits(&regparse);
  	else
  	    *maxval = MAX_LIMIT;
      }
      else if (VIM_ISDIGIT(*first_char))
  	*maxval = *minval;	    /* It was \{n} or \{-n} */
      else
  	*maxval = MAX_LIMIT;	    /* It was \{} or \{-} */
      if (*regparse == '\\')
  	regparse++;	/* Allow either \{...} or \{...\} */
      if (*regparse != '}')
      {
  	sprintf((char *)IObuff, _("E554: Syntax error in %s{...}"),
  					  reg_magic == MAGIC_ALL ? "" : "\\");
  	EMSG_RET_FAIL(IObuff);
      }
  
      /*
       * Reverse the range if there was a '-', or make sure it is in the right
       * order otherwise.
       */
      if ((!reverse && *minval > *maxval) || (reverse && *minval < *maxval))
      {
  	tmp = *minval;
  	*minval = *maxval;
  	*maxval = tmp;
      }
      skipchr();		/* let's be friends with the lexer again */
      return OK;
  }
  
  /*
   * vim_regexec and friends
   */
  
  /*
   * Global work variables for vim_regexec().
   */
  
  /* The current match-position is remembered with these variables: */
  static linenr_T	reglnum;	/* line number, relative to first line */
  static char_u	*regline;	/* start of current line */
  static char_u	*reginput;	/* current input, points into "regline" */
  
  static int	need_clear_subexpr;	/* subexpressions still need to be
  					 * cleared */
  #ifdef FEAT_SYN_HL
  static int	need_clear_zsubexpr = FALSE;	/* extmatch subexpressions
  						 * still need to be cleared */
  #endif
  
  /*
   * Structure used to save the current input state, when it needs to be
   * restored after trying a match.  Used by reg_save() and reg_restore().
   * Also stores the length of "backpos".
   */
  typedef struct
  {
      union
      {
  	char_u	*ptr;	/* reginput pointer, for single-line regexp */
  	lpos_T	pos;	/* reginput pos, for multi-line regexp */
      } rs_u;
      int		rs_len;
  } regsave_T;
  
  /* struct to save start/end pointer/position in for \(\) */
  typedef struct
  {
      union
      {
  	char_u	*ptr;
  	lpos_T	pos;
      } se_u;
  } save_se_T;
  
  /* used for BEHIND and NOBEHIND matching */
  typedef struct regbehind_S
  {
      regsave_T	save_after;
      regsave_T	save_behind;
      int		save_need_clear_subexpr;
      save_se_T   save_start[NSUBEXP];
      save_se_T   save_end[NSUBEXP];
  } regbehind_T;
  
  static char_u	*reg_getline(linenr_T lnum);
  static long	bt_regexec_both(char_u *line, colnr_T col, proftime_T *tm);
  static long	regtry(bt_regprog_T *prog, colnr_T col);
  static void	cleanup_subexpr(void);
  #ifdef FEAT_SYN_HL
  static void	cleanup_zsubexpr(void);
  #endif
  static void	save_subexpr(regbehind_T *bp);
  static void	restore_subexpr(regbehind_T *bp);
  static void	reg_nextline(void);
  static void	reg_save(regsave_T *save, garray_T *gap);
  static void	reg_restore(regsave_T *save, garray_T *gap);
  static int	reg_save_equal(regsave_T *save);
  static void	save_se_multi(save_se_T *savep, lpos_T *posp);
  static void	save_se_one(save_se_T *savep, char_u **pp);
  
  /* Save the sub-expressions before attempting a match. */
  #define save_se(savep, posp, pp) \
      REG_MULTI ? save_se_multi((savep), (posp)) : save_se_one((savep), (pp))
  
  /* After a failed match restore the sub-expressions. */
  #define restore_se(savep, posp, pp) { \
      if (REG_MULTI) \
  	*(posp) = (savep)->se_u.pos; \
      else \
  	*(pp) = (savep)->se_u.ptr; }
  
  static int	re_num_cmp(long_u val, char_u *scan);
  static int	match_with_backref(linenr_T start_lnum, colnr_T start_col, linenr_T end_lnum, colnr_T end_col, int *bytelen);
  static int	regmatch(char_u *prog);
  static int	regrepeat(char_u *p, long maxcount);
  
  #ifdef DEBUG
  int		regnarrate = 0;
  #endif
  
  /*
   * Internal copy of 'ignorecase'.  It is set at each call to vim_regexec().
   * Normally it gets the value of "rm_ic" or "rmm_ic", but when the pattern
   * contains '\c' or '\C' the value is overruled.
   */
  static int	ireg_ic;
  
  #ifdef FEAT_MBYTE
  /*
   * Similar to ireg_ic, but only for 'combining' characters.  Set with \Z flag
   * in the regexp.  Defaults to false, always.
   */
  static int	ireg_icombine;
  #endif
  
  /*
   * Copy of "rmm_maxcol": maximum column to search for a match.  Zero when
   * there is no maximum.
   */
  static colnr_T	ireg_maxcol;
  
  /*
   * Sometimes need to save a copy of a line.  Since alloc()/free() is very
   * slow, we keep one allocated piece of memory and only re-allocate it when
   * it's too small.  It's freed in bt_regexec_both() when finished.
   */
  static char_u	*reg_tofree = NULL;
  static unsigned	reg_tofreelen;
  
  /*
   * These variables are set when executing a regexp to speed up the execution.
   * Which ones are set depends on whether a single-line or multi-line match is
   * done:
   *			single-line		multi-line
   * reg_match		&regmatch_T		NULL
   * reg_mmatch		NULL			&regmmatch_T
   * reg_startp		reg_match->startp	<invalid>
   * reg_endp		reg_match->endp		<invalid>
   * reg_startpos		<invalid>		reg_mmatch->startpos
   * reg_endpos		<invalid>		reg_mmatch->endpos
   * reg_win		NULL			window in which to search
   * reg_buf		curbuf			buffer in which to search
   * reg_firstlnum	<invalid>		first line in which to search
   * reg_maxline		0			last line nr
   * reg_line_lbr		FALSE or TRUE		FALSE
   */
  static regmatch_T	*reg_match;
  static regmmatch_T	*reg_mmatch;
  static char_u		**reg_startp = NULL;
  static char_u		**reg_endp = NULL;
  static lpos_T		*reg_startpos = NULL;
  static lpos_T		*reg_endpos = NULL;
  static win_T		*reg_win;
  static buf_T		*reg_buf;
  static linenr_T		reg_firstlnum;
  static linenr_T		reg_maxline;
  static int		reg_line_lbr;	    /* "\n" in string is line break */
  
  /* Values for rs_state in regitem_T. */
  typedef enum regstate_E
  {
      RS_NOPEN = 0	/* NOPEN and NCLOSE */
      , RS_MOPEN		/* MOPEN + [0-9] */
      , RS_MCLOSE		/* MCLOSE + [0-9] */
  #ifdef FEAT_SYN_HL
      , RS_ZOPEN		/* ZOPEN + [0-9] */
      , RS_ZCLOSE		/* ZCLOSE + [0-9] */
  #endif
      , RS_BRANCH		/* BRANCH */
      , RS_BRCPLX_MORE	/* BRACE_COMPLEX and trying one more match */
      , RS_BRCPLX_LONG	/* BRACE_COMPLEX and trying longest match */
      , RS_BRCPLX_SHORT	/* BRACE_COMPLEX and trying shortest match */
      , RS_NOMATCH	/* NOMATCH */
      , RS_BEHIND1	/* BEHIND / NOBEHIND matching rest */
      , RS_BEHIND2	/* BEHIND / NOBEHIND matching behind part */
      , RS_STAR_LONG	/* STAR/PLUS/BRACE_SIMPLE longest match */
      , RS_STAR_SHORT	/* STAR/PLUS/BRACE_SIMPLE shortest match */
  } regstate_T;
  
  /*
   * When there are alternatives a regstate_T is put on the regstack to remember
   * what we are doing.
   * Before it may be another type of item, depending on rs_state, to remember
   * more things.
   */
  typedef struct regitem_S
  {
      regstate_T	rs_state;	/* what we are doing, one of RS_ above */
      char_u	*rs_scan;	/* current node in program */
      union
      {
  	save_se_T  sesave;
  	regsave_T  regsave;
      } rs_un;			/* room for saving reginput */
      short	rs_no;		/* submatch nr or BEHIND/NOBEHIND */
  } regitem_T;
  
  static regitem_T *regstack_push(regstate_T state, char_u *scan);
  static void regstack_pop(char_u **scan);
  
  /* used for STAR, PLUS and BRACE_SIMPLE matching */
  typedef struct regstar_S
  {
      int		nextb;		/* next byte */
      int		nextb_ic;	/* next byte reverse case */
      long	count;
      long	minval;
      long	maxval;
  } regstar_T;
  
  /* used to store input position when a BACK was encountered, so that we now if
   * we made any progress since the last time. */
  typedef struct backpos_S
  {
      char_u	*bp_scan;	/* "scan" where BACK was encountered */
      regsave_T	bp_pos;		/* last input position */
  } backpos_T;
  
  /*
   * "regstack" and "backpos" are used by regmatch().  They are kept over calls
   * to avoid invoking malloc() and free() often.
   * "regstack" is a stack with regitem_T items, sometimes preceded by regstar_T
   * or regbehind_T.
   * "backpos_T" is a table with backpos_T for BACK
   */
  static garray_T	regstack = {0, 0, 0, 0, NULL};
  static garray_T	backpos = {0, 0, 0, 0, NULL};
  
  /*
   * Both for regstack and backpos tables we use the following strategy of
   * allocation (to reduce malloc/free calls):
   * - Initial size is fairly small.
   * - When needed, the tables are grown bigger (8 times at first, double after
   *   that).
   * - After executing the match we free the memory only if the array has grown.
   *   Thus the memory is kept allocated when it's at the initial size.
   * This makes it fast while not keeping a lot of memory allocated.
   * A three times speed increase was observed when using many simple patterns.
   */
  #define REGSTACK_INITIAL	2048
  #define BACKPOS_INITIAL		64
  
  #if defined(EXITFREE) || defined(PROTO)
      void
  free_regexp_stuff(void)
  {
      ga_clear(&regstack);
      ga_clear(&backpos);
      vim_free(reg_tofree);
      vim_free(reg_prev_sub);
  }
  #endif
  
  /*
   * Get pointer to the line "lnum", which is relative to "reg_firstlnum".
   */
      static char_u *
  reg_getline(linenr_T lnum)
  {
      /* when looking behind for a match/no-match lnum is negative.  But we
       * can't go before line 1 */
      if (reg_firstlnum + lnum < 1)
  	return NULL;
      if (lnum > reg_maxline)
  	/* Must have matched the "\n" in the last line. */
  	return (char_u *)"";
      return ml_get_buf(reg_buf, reg_firstlnum + lnum, FALSE);
  }
  
  static regsave_T behind_pos;
  
  #ifdef FEAT_SYN_HL
  static char_u	*reg_startzp[NSUBEXP];	/* Workspace to mark beginning */
  static char_u	*reg_endzp[NSUBEXP];	/*   and end of \z(...\) matches */
  static lpos_T	reg_startzpos[NSUBEXP];	/* idem, beginning pos */
  static lpos_T	reg_endzpos[NSUBEXP];	/* idem, end pos */
  #endif
  
  /* TRUE if using multi-line regexp. */
  #define REG_MULTI	(reg_match == NULL)
  
  static int  bt_regexec_nl(regmatch_T *rmp, char_u *line, colnr_T col, int line_lbr);
  
  
  /*
   * Match a regexp against a string.
   * "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
   * Uses curbuf for line count and 'iskeyword'.
   * if "line_lbr" is TRUE  consider a "\n" in "line" to be a line break.
   *
   * Returns 0 for failure, number of lines contained in the match otherwise.
   */
      static int
  bt_regexec_nl(
      regmatch_T	*rmp,
      char_u	*line,	/* string to match against */
      colnr_T	col,	/* column to start looking for match */
      int		line_lbr)
  {
      reg_match = rmp;
      reg_mmatch = NULL;
      reg_maxline = 0;
      reg_line_lbr = line_lbr;
      reg_buf = curbuf;
      reg_win = NULL;
      ireg_ic = rmp->rm_ic;
  #ifdef FEAT_MBYTE
      ireg_icombine = FALSE;
  #endif
      ireg_maxcol = 0;
  
      return bt_regexec_both(line, col, NULL);
  }
  
  static long bt_regexec_multi(regmmatch_T *rmp, win_T *win, buf_T *buf, linenr_T lnum, colnr_T col, proftime_T *tm);
  
  /*
   * Match a regexp against multiple lines.
   * "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
   * Uses curbuf for line count and 'iskeyword'.
   *
   * Return zero if there is no match.  Return number of lines contained in the
   * match otherwise.
   */
      static long
  bt_regexec_multi(
      regmmatch_T	*rmp,
      win_T	*win,		/* window in which to search or NULL */
      buf_T	*buf,		/* buffer in which to search */
      linenr_T	lnum,		/* nr of line to start looking for match */
      colnr_T	col,		/* column to start looking for match */
      proftime_T	*tm)		/* timeout limit or NULL */
  {
      reg_match = NULL;
      reg_mmatch = rmp;
      reg_buf = buf;
      reg_win = win;
      reg_firstlnum = lnum;
      reg_maxline = reg_buf->b_ml.ml_line_count - lnum;
      reg_line_lbr = FALSE;
      ireg_ic = rmp->rmm_ic;
  #ifdef FEAT_MBYTE
      ireg_icombine = FALSE;
  #endif
      ireg_maxcol = rmp->rmm_maxcol;
  
      return bt_regexec_both(NULL, col, tm);
  }
  
  /*
   * Match a regexp against a string ("line" points to the string) or multiple
   * lines ("line" is NULL, use reg_getline()).
   * Returns 0 for failure, number of lines contained in the match otherwise.
   */
      static long
  bt_regexec_both(
      char_u	*line,
      colnr_T	col,		/* column to start looking for match */
      proftime_T	*tm UNUSED)	/* timeout limit or NULL */
  {
      bt_regprog_T    *prog;
      char_u	    *s;
      long	    retval = 0L;
  
      /* Create "regstack" and "backpos" if they are not allocated yet.
       * We allocate *_INITIAL amount of bytes first and then set the grow size
       * to much bigger value to avoid many malloc calls in case of deep regular
       * expressions.  */
      if (regstack.ga_data == NULL)
      {
  	/* Use an item size of 1 byte, since we push different things
  	 * onto the regstack. */
  	ga_init2(&regstack, 1, REGSTACK_INITIAL);
  	(void)ga_grow(&regstack, REGSTACK_INITIAL);
  	regstack.ga_growsize = REGSTACK_INITIAL * 8;
      }
  
      if (backpos.ga_data == NULL)
      {
  	ga_init2(&backpos, sizeof(backpos_T), BACKPOS_INITIAL);
  	(void)ga_grow(&backpos, BACKPOS_INITIAL);
  	backpos.ga_growsize = BACKPOS_INITIAL * 8;
      }
  
      if (REG_MULTI)
      {
  	prog = (bt_regprog_T *)reg_mmatch->regprog;
  	line = reg_getline((linenr_T)0);
  	reg_startpos = reg_mmatch->startpos;
  	reg_endpos = reg_mmatch->endpos;
      }
      else
      {
  	prog = (bt_regprog_T *)reg_match->regprog;
  	reg_startp = reg_match->startp;
  	reg_endp = reg_match->endp;
      }
  
      /* Be paranoid... */
      if (prog == NULL || line == NULL)
      {
  	EMSG(_(e_null));
  	goto theend;
      }
  
      /* Check validity of program. */
      if (prog_magic_wrong())
  	goto theend;
  
      /* If the start column is past the maximum column: no need to try. */
      if (ireg_maxcol > 0 && col >= ireg_maxcol)
  	goto theend;
  
      /* If pattern contains "\c" or "\C": overrule value of ireg_ic */
      if (prog->regflags & RF_ICASE)
  	ireg_ic = TRUE;
      else if (prog->regflags & RF_NOICASE)
  	ireg_ic = FALSE;
  
  #ifdef FEAT_MBYTE
      /* If pattern contains "\Z" overrule value of ireg_icombine */
      if (prog->regflags & RF_ICOMBINE)
  	ireg_icombine = TRUE;
  #endif
  
      /* If there is a "must appear" string, look for it. */
      if (prog->regmust != NULL)
      {
  	int c;
  
  #ifdef FEAT_MBYTE
  	if (has_mbyte)
  	    c = (*mb_ptr2char)(prog->regmust);
  	else
  #endif
  	    c = *prog->regmust;
  	s = line + col;
  
  	/*
  	 * This is used very often, esp. for ":global".  Use three versions of
  	 * the loop to avoid overhead of conditions.
  	 */
  	if (!ireg_ic
  #ifdef FEAT_MBYTE
  		&& !has_mbyte
  #endif
  		)
  	    while ((s = vim_strbyte(s, c)) != NULL)
  	    {
  		if (cstrncmp(s, prog->regmust, &prog->regmlen) == 0)
  		    break;		/* Found it. */
  		++s;
  	    }
  #ifdef FEAT_MBYTE
  	else if (!ireg_ic || (!enc_utf8 && mb_char2len(c) > 1))
  	    while ((s = vim_strchr(s, c)) != NULL)
  	    {
  		if (cstrncmp(s, prog->regmust, &prog->regmlen) == 0)
  		    break;		/* Found it. */
  		mb_ptr_adv(s);
  	    }
  #endif
  	else
  	    while ((s = cstrchr(s, c)) != NULL)
  	    {
  		if (cstrncmp(s, prog->regmust, &prog->regmlen) == 0)
  		    break;		/* Found it. */
  		mb_ptr_adv(s);
  	    }
  	if (s == NULL)		/* Not present. */
  	    goto theend;
      }
  
      regline = line;
      reglnum = 0;
      reg_toolong = FALSE;
  
      /* Simplest case: Anchored match need be tried only once. */
      if (prog->reganch)
      {
  	int	c;
  
  #ifdef FEAT_MBYTE
  	if (has_mbyte)
  	    c = (*mb_ptr2char)(regline + col);
  	else
  #endif
  	    c = regline[col];
  	if (prog->regstart == NUL
  		|| prog->regstart == c
  		|| (ireg_ic && ((
  #ifdef FEAT_MBYTE
  			(enc_utf8 && utf_fold(prog->regstart) == utf_fold(c)))
  			|| (c < 255 && prog->regstart < 255 &&
  #endif
  			    MB_TOLOWER(prog->regstart) == MB_TOLOWER(c)))))
  	    retval = regtry(prog, col);
  	else
  	    retval = 0;
      }
      else
      {
  #ifdef FEAT_RELTIME
  	int tm_count = 0;
  #endif
  	/* Messy cases:  unanchored match. */
  	while (!got_int)
  	{
  	    if (prog->regstart != NUL)
  	    {
  		/* Skip until the char we know it must start with.
  		 * Used often, do some work to avoid call overhead. */
  		if (!ireg_ic
  #ifdef FEAT_MBYTE
  			    && !has_mbyte
  #endif
  			    )
  		    s = vim_strbyte(regline + col, prog->regstart);
  		else
  		    s = cstrchr(regline + col, prog->regstart);
  		if (s == NULL)
  		{
  		    retval = 0;
  		    break;
  		}
  		col = (int)(s - regline);
  	    }
  
  	    /* Check for maximum column to try. */
  	    if (ireg_maxcol > 0 && col >= ireg_maxcol)
  	    {
  		retval = 0;
  		break;
  	    }
  
  	    retval = regtry(prog, col);
  	    if (retval > 0)
  		break;
  
  	    /* if not currently on the first line, get it again */
  	    if (reglnum != 0)
  	    {
  		reglnum = 0;
  		regline = reg_getline((linenr_T)0);
  	    }
  	    if (regline[col] == NUL)
  		break;
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  		col += (*mb_ptr2len)(regline + col);
  	    else
  #endif
  		++col;
  #ifdef FEAT_RELTIME
  	    /* Check for timeout once in a twenty times to avoid overhead. */
  	    if (tm != NULL && ++tm_count == 20)
  	    {
  		tm_count = 0;
  		if (profile_passed_limit(tm))
  		    break;
  	    }
  #endif
  	}
      }
  
  theend:
      /* Free "reg_tofree" when it's a bit big.
       * Free regstack and backpos if they are bigger than their initial size. */
      if (reg_tofreelen > 400)
      {
  	vim_free(reg_tofree);
  	reg_tofree = NULL;
      }
      if (regstack.ga_maxlen > REGSTACK_INITIAL)
  	ga_clear(&regstack);
      if (backpos.ga_maxlen > BACKPOS_INITIAL)
  	ga_clear(&backpos);
  
      return retval;
  }
  
  #ifdef FEAT_SYN_HL
  static reg_extmatch_T *make_extmatch(void);
  
  /*
   * Create a new extmatch and mark it as referenced once.
   */
      static reg_extmatch_T *
  make_extmatch(void)
  {
      reg_extmatch_T	*em;
  
      em = (reg_extmatch_T *)alloc_clear((unsigned)sizeof(reg_extmatch_T));
      if (em != NULL)
  	em->refcnt = 1;
      return em;
  }
  
  /*
   * Add a reference to an extmatch.
   */
      reg_extmatch_T *
  ref_extmatch(reg_extmatch_T *em)
  {
      if (em != NULL)
  	em->refcnt++;
      return em;
  }
  
  /*
   * Remove a reference to an extmatch.  If there are no references left, free
   * the info.
   */
      void
  unref_extmatch(reg_extmatch_T *em)
  {
      int i;
  
      if (em != NULL && --em->refcnt <= 0)
      {
  	for (i = 0; i < NSUBEXP; ++i)
  	    vim_free(em->matches[i]);
  	vim_free(em);
      }
  }
  #endif
  
  /*
   * regtry - try match of "prog" with at regline["col"].
   * Returns 0 for failure, number of lines contained in the match otherwise.
   */
      static long
  regtry(bt_regprog_T *prog, colnr_T col)
  {
      reginput = regline + col;
      need_clear_subexpr = TRUE;
  #ifdef FEAT_SYN_HL
      /* Clear the external match subpointers if necessary. */
      if (prog->reghasz == REX_SET)
  	need_clear_zsubexpr = TRUE;
  #endif
  
      if (regmatch(prog->program + 1) == 0)
  	return 0;
  
      cleanup_subexpr();
      if (REG_MULTI)
      {
  	if (reg_startpos[0].lnum < 0)
  	{
  	    reg_startpos[0].lnum = 0;
  	    reg_startpos[0].col = col;
  	}
  	if (reg_endpos[0].lnum < 0)
  	{
  	    reg_endpos[0].lnum = reglnum;
  	    reg_endpos[0].col = (int)(reginput - regline);
  	}
  	else
  	    /* Use line number of "\ze". */
  	    reglnum = reg_endpos[0].lnum;
      }
      else
      {
  	if (reg_startp[0] == NULL)
  	    reg_startp[0] = regline + col;
  	if (reg_endp[0] == NULL)
  	    reg_endp[0] = reginput;
      }
  #ifdef FEAT_SYN_HL
      /* Package any found \z(...\) matches for export. Default is none. */
      unref_extmatch(re_extmatch_out);
      re_extmatch_out = NULL;
  
      if (prog->reghasz == REX_SET)
      {
  	int		i;
  
  	cleanup_zsubexpr();
  	re_extmatch_out = make_extmatch();
  	for (i = 0; i < NSUBEXP; i++)
  	{
  	    if (REG_MULTI)
  	    {
  		/* Only accept single line matches. */
  		if (reg_startzpos[i].lnum >= 0
  			&& reg_endzpos[i].lnum == reg_startzpos[i].lnum
  			&& reg_endzpos[i].col >= reg_startzpos[i].col)
  		    re_extmatch_out->matches[i] =
  			vim_strnsave(reg_getline(reg_startzpos[i].lnum)
  						       + reg_startzpos[i].col,
  				   reg_endzpos[i].col - reg_startzpos[i].col);
  	    }
  	    else
  	    {
  		if (reg_startzp[i] != NULL && reg_endzp[i] != NULL)
  		    re_extmatch_out->matches[i] =
  			    vim_strnsave(reg_startzp[i],
  					(int)(reg_endzp[i] - reg_startzp[i]));
  	    }
  	}
      }
  #endif
      return 1 + reglnum;
  }
  
  #ifdef FEAT_MBYTE
  static int reg_prev_class(void);
  
  /*
   * Get class of previous character.
   */
      static int
  reg_prev_class(void)
  {
      if (reginput > regline)
  	return mb_get_class_buf(reginput - 1
  			    - (*mb_head_off)(regline, reginput - 1), reg_buf);
      return -1;
  }
  #endif
  
  static int reg_match_visual(void);
  
  /*
   * Return TRUE if the current reginput position matches the Visual area.
   */
      static int
  reg_match_visual(void)
  {
      pos_T	top, bot;
      linenr_T    lnum;
      colnr_T	col;
      win_T	*wp = reg_win == NULL ? curwin : reg_win;
      int		mode;
      colnr_T	start, end;
      colnr_T	start2, end2;
      colnr_T	cols;
  
      /* Check if the buffer is the current buffer. */
      if (reg_buf != curbuf || VIsual.lnum == 0)
  	return FALSE;
  
      if (VIsual_active)
      {
  	if (lt(VIsual, wp->w_cursor))
  	{
  	    top = VIsual;
  	    bot = wp->w_cursor;
  	}
  	else
  	{
  	    top = wp->w_cursor;
  	    bot = VIsual;
  	}
  	mode = VIsual_mode;
      }
      else
      {
  	if (lt(curbuf->b_visual.vi_start, curbuf->b_visual.vi_end))
  	{
  	    top = curbuf->b_visual.vi_start;
  	    bot = curbuf->b_visual.vi_end;
  	}
  	else
  	{
  	    top = curbuf->b_visual.vi_end;
  	    bot = curbuf->b_visual.vi_start;
  	}
  	mode = curbuf->b_visual.vi_mode;
      }
      lnum = reglnum + reg_firstlnum;
      if (lnum < top.lnum || lnum > bot.lnum)
  	return FALSE;
  
      if (mode == 'v')
      {
  	col = (colnr_T)(reginput - regline);
  	if ((lnum == top.lnum && col < top.col)
  		|| (lnum == bot.lnum && col >= bot.col + (*p_sel != 'e')))
  	    return FALSE;
      }
      else if (mode == Ctrl_V)
      {
  	getvvcol(wp, &top, &start, NULL, &end);
  	getvvcol(wp, &bot, &start2, NULL, &end2);
  	if (start2 < start)
  	    start = start2;
  	if (end2 > end)
  	    end = end2;
  	if (top.col == MAXCOL || bot.col == MAXCOL)
  	    end = MAXCOL;
  	cols = win_linetabsize(wp, regline, (colnr_T)(reginput - regline));
  	if (cols < start || cols > end - (*p_sel == 'e'))
  	    return FALSE;
      }
      return TRUE;
  }
  
  #define ADVANCE_REGINPUT() mb_ptr_adv(reginput)
  
  /*
   * The arguments from BRACE_LIMITS are stored here.  They are actually local
   * to regmatch(), but they are here to reduce the amount of stack space used
   * (it can be called recursively many times).
   */
  static long	bl_minval;
  static long	bl_maxval;
  
  /*
   * regmatch - main matching routine
   *
   * Conceptually the strategy is simple: Check to see whether the current node
   * matches, push an item onto the regstack and loop to see whether the rest
   * matches, and then act accordingly.  In practice we make some effort to
   * avoid using the regstack, in particular by going through "ordinary" nodes
   * (that don't need to know whether the rest of the match failed) by a nested
   * loop.
   *
   * Returns TRUE when there is a match.  Leaves reginput and reglnum just after
   * the last matched character.
   * Returns FALSE when there is no match.  Leaves reginput and reglnum in an
   * undefined state!
   */
      static int
  regmatch(
      char_u	*scan)		/* Current node. */
  {
    char_u	*next;		/* Next node. */
    int		op;
    int		c;
    regitem_T	*rp;
    int		no;
    int		status;		/* one of the RA_ values: */
  #define RA_FAIL		1	/* something failed, abort */
  #define RA_CONT		2	/* continue in inner loop */
  #define RA_BREAK	3	/* break inner loop */
  #define RA_MATCH	4	/* successful match */
  #define RA_NOMATCH	5	/* didn't match */
  
    /* Make "regstack" and "backpos" empty.  They are allocated and freed in
     * bt_regexec_both() to reduce malloc()/free() calls. */
    regstack.ga_len = 0;
    backpos.ga_len = 0;
  
    /*
     * Repeat until "regstack" is empty.
     */
    for (;;)
    {
      /* Some patterns may take a long time to match, e.g., "\([a-z]\+\)\+Q".
       * Allow interrupting them with CTRL-C. */
      fast_breakcheck();
  
  #ifdef DEBUG
      if (scan != NULL && regnarrate)
      {
  	mch_errmsg((char *)regprop(scan));
  	mch_errmsg("(\n");
      }
  #endif
  
      /*
       * Repeat for items that can be matched sequentially, without using the
       * regstack.
       */
      for (;;)
      {
  	if (got_int || scan == NULL)
  	{
  	    status = RA_FAIL;
  	    break;
  	}
  	status = RA_CONT;
  
  #ifdef DEBUG
  	if (regnarrate)
  	{
  	    mch_errmsg((char *)regprop(scan));
  	    mch_errmsg("...\n");
  # ifdef FEAT_SYN_HL
  	    if (re_extmatch_in != NULL)
  	    {
  		int i;
  
  		mch_errmsg(_("External submatches:\n"));
  		for (i = 0; i < NSUBEXP; i++)
  		{
  		    mch_errmsg("    \"");
  		    if (re_extmatch_in->matches[i] != NULL)
  			mch_errmsg((char *)re_extmatch_in->matches[i]);
  		    mch_errmsg("\"\n");
  		}
  	    }
  # endif
  	}
  #endif
  	next = regnext(scan);
  
  	op = OP(scan);
  	/* Check for character class with NL added. */
  	if (!reg_line_lbr && WITH_NL(op) && REG_MULTI
  				&& *reginput == NUL && reglnum <= reg_maxline)
  	{
  	    reg_nextline();
  	}
  	else if (reg_line_lbr && WITH_NL(op) && *reginput == '\n')
  	{
  	    ADVANCE_REGINPUT();
  	}
  	else
  	{
  	  if (WITH_NL(op))
  	      op -= ADD_NL;
  #ifdef FEAT_MBYTE
  	  if (has_mbyte)
  	      c = (*mb_ptr2char)(reginput);
  	  else
  #endif
  	      c = *reginput;
  	  switch (op)
  	  {
  	  case BOL:
  	    if (reginput != regline)
  		status = RA_NOMATCH;
  	    break;
  
  	  case EOL:
  	    if (c != NUL)
  		status = RA_NOMATCH;
  	    break;
  
  	  case RE_BOF:
  	    /* We're not at the beginning of the file when below the first
  	     * line where we started, not at the start of the line or we
  	     * didn't start at the first line of the buffer. */
  	    if (reglnum != 0 || reginput != regline
  					  || (REG_MULTI && reg_firstlnum > 1))
  		status = RA_NOMATCH;
  	    break;
  
  	  case RE_EOF:
  	    if (reglnum != reg_maxline || c != NUL)
  		status = RA_NOMATCH;
  	    break;
  
  	  case CURSOR:
  	    /* Check if the buffer is in a window and compare the
  	     * reg_win->w_cursor position to the match position. */
  	    if (reg_win == NULL
  		    || (reglnum + reg_firstlnum != reg_win->w_cursor.lnum)
  		    || ((colnr_T)(reginput - regline) != reg_win->w_cursor.col))
  		status = RA_NOMATCH;
  	    break;
  
  	  case RE_MARK:
  	    /* Compare the mark position to the match position. */
  	    {
  		int	mark = OPERAND(scan)[0];
  		int	cmp = OPERAND(scan)[1];
  		pos_T	*pos;
  
  		pos = getmark_buf(reg_buf, mark, FALSE);
  		if (pos == NULL		     /* mark doesn't exist */
  			|| pos->lnum <= 0    /* mark isn't set in reg_buf */
  			|| (pos->lnum == reglnum + reg_firstlnum
  				? (pos->col == (colnr_T)(reginput - regline)
  				    ? (cmp == '<' || cmp == '>')
  				    : (pos->col < (colnr_T)(reginput - regline)
  					? cmp != '>'
  					: cmp != '<'))
  				: (pos->lnum < reglnum + reg_firstlnum
  				    ? cmp != '>'
  				    : cmp != '<')))
  		    status = RA_NOMATCH;
  	    }
  	    break;
  
  	  case RE_VISUAL:
  	    if (!reg_match_visual())
  		status = RA_NOMATCH;
  	    break;
  
  	  case RE_LNUM:
  	    if (!REG_MULTI || !re_num_cmp((long_u)(reglnum + reg_firstlnum),
  									scan))
  		status = RA_NOMATCH;
  	    break;
  
  	  case RE_COL:
  	    if (!re_num_cmp((long_u)(reginput - regline) + 1, scan))
  		status = RA_NOMATCH;
  	    break;
  
  	  case RE_VCOL:
  	    if (!re_num_cmp((long_u)win_linetabsize(
  			    reg_win == NULL ? curwin : reg_win,
  			    regline, (colnr_T)(reginput - regline)) + 1, scan))
  		status = RA_NOMATCH;
  	    break;
  
  	  case BOW:	/* \<word; reginput points to w */
  	    if (c == NUL)	/* Can't match at end of line */
  		status = RA_NOMATCH;
  #ifdef FEAT_MBYTE
  	    else if (has_mbyte)
  	    {
  		int this_class;
  
  		/* Get class of current and previous char (if it exists). */
  		this_class = mb_get_class_buf(reginput, reg_buf);
  		if (this_class <= 1)
  		    status = RA_NOMATCH;  /* not on a word at all */
  		else if (reg_prev_class() == this_class)
  		    status = RA_NOMATCH;  /* previous char is in same word */
  	    }
  #endif
  	    else
  	    {
  		if (!vim_iswordc_buf(c, reg_buf) || (reginput > regline
  				   && vim_iswordc_buf(reginput[-1], reg_buf)))
  		    status = RA_NOMATCH;
  	    }
  	    break;
  
  	  case EOW:	/* word\>; reginput points after d */
  	    if (reginput == regline)    /* Can't match at start of line */
  		status = RA_NOMATCH;
  #ifdef FEAT_MBYTE
  	    else if (has_mbyte)
  	    {
  		int this_class, prev_class;
  
  		/* Get class of current and previous char (if it exists). */
  		this_class = mb_get_class_buf(reginput, reg_buf);
  		prev_class = reg_prev_class();
  		if (this_class == prev_class
  			|| prev_class == 0 || prev_class == 1)
  		    status = RA_NOMATCH;
  	    }
  #endif
  	    else
  	    {
  		if (!vim_iswordc_buf(reginput[-1], reg_buf)
  			|| (reginput[0] != NUL && vim_iswordc_buf(c, reg_buf)))
  		    status = RA_NOMATCH;
  	    }
  	    break; /* Matched with EOW */
  
  	  case ANY:
  	    /* ANY does not match new lines. */
  	    if (c == NUL)
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case IDENT:
  	    if (!vim_isIDc(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case SIDENT:
  	    if (VIM_ISDIGIT(*reginput) || !vim_isIDc(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case KWORD:
  	    if (!vim_iswordp_buf(reginput, reg_buf))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case SKWORD:
  	    if (VIM_ISDIGIT(*reginput) || !vim_iswordp_buf(reginput, reg_buf))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case FNAME:
  	    if (!vim_isfilec(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case SFNAME:
  	    if (VIM_ISDIGIT(*reginput) || !vim_isfilec(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case PRINT:
  	    if (!vim_isprintc(PTR2CHAR(reginput)))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case SPRINT:
  	    if (VIM_ISDIGIT(*reginput) || !vim_isprintc(PTR2CHAR(reginput)))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case WHITE:
  	    if (!vim_iswhite(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NWHITE:
  	    if (c == NUL || vim_iswhite(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case DIGIT:
  	    if (!ri_digit(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NDIGIT:
  	    if (c == NUL || ri_digit(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case HEX:
  	    if (!ri_hex(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NHEX:
  	    if (c == NUL || ri_hex(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case OCTAL:
  	    if (!ri_octal(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NOCTAL:
  	    if (c == NUL || ri_octal(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case WORD:
  	    if (!ri_word(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NWORD:
  	    if (c == NUL || ri_word(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case HEAD:
  	    if (!ri_head(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NHEAD:
  	    if (c == NUL || ri_head(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case ALPHA:
  	    if (!ri_alpha(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NALPHA:
  	    if (c == NUL || ri_alpha(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case LOWER:
  	    if (!ri_lower(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NLOWER:
  	    if (c == NUL || ri_lower(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case UPPER:
  	    if (!ri_upper(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case NUPPER:
  	    if (c == NUL || ri_upper(c))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  	  case EXACTLY:
  	    {
  		int	len;
  		char_u	*opnd;
  
  		opnd = OPERAND(scan);
  		/* Inline the first byte, for speed. */
  		if (*opnd != *reginput
  			&& (!ireg_ic || (
  #ifdef FEAT_MBYTE
  			    !enc_utf8 &&
  #endif
  			    MB_TOLOWER(*opnd) != MB_TOLOWER(*reginput))))
  		    status = RA_NOMATCH;
  		else if (*opnd == NUL)
  		{
  		    /* match empty string always works; happens when "~" is
  		     * empty. */
  		}
  		else
  		{
  		    if (opnd[1] == NUL
  #ifdef FEAT_MBYTE
  			    && !(enc_utf8 && ireg_ic)
  #endif
  			)
  		    {
  			len = 1;	/* matched a single byte above */
  		    }
  		    else
  		    {
  			/* Need to match first byte again for multi-byte. */
  			len = (int)STRLEN(opnd);
  			if (cstrncmp(opnd, reginput, &len) != 0)
  			    status = RA_NOMATCH;
  		    }
  #ifdef FEAT_MBYTE
  		    /* Check for following composing character, unless %C
  		     * follows (skips over all composing chars). */
  		    if (status != RA_NOMATCH
  			    && enc_utf8
  			    && UTF_COMPOSINGLIKE(reginput, reginput + len)
  			    && !ireg_icombine
  			    && OP(next) != RE_COMPOSING)
  		    {
  			/* raaron: This code makes a composing character get
  			 * ignored, which is the correct behavior (sometimes)
  			 * for voweled Hebrew texts. */
  			status = RA_NOMATCH;
  		    }
  #endif
  		    if (status != RA_NOMATCH)
  			reginput += len;
  		}
  	    }
  	    break;
  
  	  case ANYOF:
  	  case ANYBUT:
  	    if (c == NUL)
  		status = RA_NOMATCH;
  	    else if ((cstrchr(OPERAND(scan), c) == NULL) == (op == ANYOF))
  		status = RA_NOMATCH;
  	    else
  		ADVANCE_REGINPUT();
  	    break;
  
  #ifdef FEAT_MBYTE
  	  case MULTIBYTECODE:
  	    if (has_mbyte)
  	    {
  		int	i, len;
  		char_u	*opnd;
  		int	opndc = 0, inpc;
  
  		opnd = OPERAND(scan);
  		/* Safety check (just in case 'encoding' was changed since
  		 * compiling the program). */
  		if ((len = (*mb_ptr2len)(opnd)) < 2)
  		{
  		    status = RA_NOMATCH;
  		    break;
  		}
  		if (enc_utf8)
  		    opndc = mb_ptr2char(opnd);
  		if (enc_utf8 && utf_iscomposing(opndc))
  		{
  		    /* When only a composing char is given match at any
  		     * position where that composing char appears. */
  		    status = RA_NOMATCH;
  		    for (i = 0; reginput[i] != NUL;
  						i += utf_ptr2len(reginput + i))
  		    {
  			inpc = mb_ptr2char(reginput + i);
  			if (!utf_iscomposing(inpc))
  			{
  			    if (i > 0)
  				break;
  			}
  			else if (opndc == inpc)
  			{
  			    /* Include all following composing chars. */
  			    len = i + mb_ptr2len(reginput + i);
  			    status = RA_MATCH;
  			    break;
  			}
  		    }
  		}
  		else
  		    for (i = 0; i < len; ++i)
  			if (opnd[i] != reginput[i])
  			{
  			    status = RA_NOMATCH;
  			    break;
  			}
  		reginput += len;
  	    }
  	    else
  		status = RA_NOMATCH;
  	    break;
  #endif
  	  case RE_COMPOSING:
  #ifdef FEAT_MBYTE
  	    if (enc_utf8)
  	    {
  		/* Skip composing characters. */
  		while (utf_iscomposing(utf_ptr2char(reginput)))
  		    mb_cptr_adv(reginput);
  	    }
  #endif
  	    break;
  
  	  case NOTHING:
  	    break;
  
  	  case BACK:
  	    {
  		int		i;
  		backpos_T	*bp;
  
  		/*
  		 * When we run into BACK we need to check if we don't keep
  		 * looping without matching any input.  The second and later
  		 * times a BACK is encountered it fails if the input is still
  		 * at the same position as the previous time.
  		 * The positions are stored in "backpos" and found by the
  		 * current value of "scan", the position in the RE program.
  		 */
  		bp = (backpos_T *)backpos.ga_data;
  		for (i = 0; i < backpos.ga_len; ++i)
  		    if (bp[i].bp_scan == scan)
  			break;
  		if (i == backpos.ga_len)
  		{
  		    /* First time at this BACK, make room to store the pos. */
  		    if (ga_grow(&backpos, 1) == FAIL)
  			status = RA_FAIL;
  		    else
  		    {
  			/* get "ga_data" again, it may have changed */
  			bp = (backpos_T *)backpos.ga_data;
  			bp[i].bp_scan = scan;
  			++backpos.ga_len;
  		    }
  		}
  		else if (reg_save_equal(&bp[i].bp_pos))
  		    /* Still at same position as last time, fail. */
  		    status = RA_NOMATCH;
  
  		if (status != RA_FAIL && status != RA_NOMATCH)
  		    reg_save(&bp[i].bp_pos, &backpos);
  	    }
  	    break;
  
  	  case MOPEN + 0:   /* Match start: \zs */
  	  case MOPEN + 1:   /* \( */
  	  case MOPEN + 2:
  	  case MOPEN + 3:
  	  case MOPEN + 4:
  	  case MOPEN + 5:
  	  case MOPEN + 6:
  	  case MOPEN + 7:
  	  case MOPEN + 8:
  	  case MOPEN + 9:
  	    {
  		no = op - MOPEN;
  		cleanup_subexpr();
  		rp = regstack_push(RS_MOPEN, scan);
  		if (rp == NULL)
  		    status = RA_FAIL;
  		else
  		{
  		    rp->rs_no = no;
  		    save_se(&rp->rs_un.sesave, &reg_startpos[no],
  							     &reg_startp[no]);
  		    /* We simply continue and handle the result when done. */
  		}
  	    }
  	    break;
  
  	  case NOPEN:	    /* \%( */
  	  case NCLOSE:	    /* \) after \%( */
  		if (regstack_push(RS_NOPEN, scan) == NULL)
  		    status = RA_FAIL;
  		/* We simply continue and handle the result when done. */
  		break;
  
  #ifdef FEAT_SYN_HL
  	  case ZOPEN + 1:
  	  case ZOPEN + 2:
  	  case ZOPEN + 3:
  	  case ZOPEN + 4:
  	  case ZOPEN + 5:
  	  case ZOPEN + 6:
  	  case ZOPEN + 7:
  	  case ZOPEN + 8:
  	  case ZOPEN + 9:
  	    {
  		no = op - ZOPEN;
  		cleanup_zsubexpr();
  		rp = regstack_push(RS_ZOPEN, scan);
  		if (rp == NULL)
  		    status = RA_FAIL;
  		else
  		{
  		    rp->rs_no = no;
  		    save_se(&rp->rs_un.sesave, &reg_startzpos[no],
  							     &reg_startzp[no]);
  		    /* We simply continue and handle the result when done. */
  		}
  	    }
  	    break;
  #endif
  
  	  case MCLOSE + 0:  /* Match end: \ze */
  	  case MCLOSE + 1:  /* \) */
  	  case MCLOSE + 2:
  	  case MCLOSE + 3:
  	  case MCLOSE + 4:
  	  case MCLOSE + 5:
  	  case MCLOSE + 6:
  	  case MCLOSE + 7:
  	  case MCLOSE + 8:
  	  case MCLOSE + 9:
  	    {
  		no = op - MCLOSE;
  		cleanup_subexpr();
  		rp = regstack_push(RS_MCLOSE, scan);
  		if (rp == NULL)
  		    status = RA_FAIL;
  		else
  		{
  		    rp->rs_no = no;
  		    save_se(&rp->rs_un.sesave, &reg_endpos[no], &reg_endp[no]);
  		    /* We simply continue and handle the result when done. */
  		}
  	    }
  	    break;
  
  #ifdef FEAT_SYN_HL
  	  case ZCLOSE + 1:  /* \) after \z( */
  	  case ZCLOSE + 2:
  	  case ZCLOSE + 3:
  	  case ZCLOSE + 4:
  	  case ZCLOSE + 5:
  	  case ZCLOSE + 6:
  	  case ZCLOSE + 7:
  	  case ZCLOSE + 8:
  	  case ZCLOSE + 9:
  	    {
  		no = op - ZCLOSE;
  		cleanup_zsubexpr();
  		rp = regstack_push(RS_ZCLOSE, scan);
  		if (rp == NULL)
  		    status = RA_FAIL;
  		else
  		{
  		    rp->rs_no = no;
  		    save_se(&rp->rs_un.sesave, &reg_endzpos[no],
  							      &reg_endzp[no]);
  		    /* We simply continue and handle the result when done. */
  		}
  	    }
  	    break;
  #endif
  
  	  case BACKREF + 1:
  	  case BACKREF + 2:
  	  case BACKREF + 3:
  	  case BACKREF + 4:
  	  case BACKREF + 5:
  	  case BACKREF + 6:
  	  case BACKREF + 7:
  	  case BACKREF + 8:
  	  case BACKREF + 9:
  	    {
  		int		len;
  
  		no = op - BACKREF;
  		cleanup_subexpr();
  		if (!REG_MULTI)		/* Single-line regexp */
  		{
  		    if (reg_startp[no] == NULL || reg_endp[no] == NULL)
  		    {
  			/* Backref was not set: Match an empty string. */
  			len = 0;
  		    }
  		    else
  		    {
  			/* Compare current input with back-ref in the same
  			 * line. */
  			len = (int)(reg_endp[no] - reg_startp[no]);
  			if (cstrncmp(reg_startp[no], reginput, &len) != 0)
  			    status = RA_NOMATCH;
  		    }
  		}
  		else				/* Multi-line regexp */
  		{
  		    if (reg_startpos[no].lnum < 0 || reg_endpos[no].lnum < 0)
  		    {
  			/* Backref was not set: Match an empty string. */
  			len = 0;
  		    }
  		    else
  		    {
  			if (reg_startpos[no].lnum == reglnum
  				&& reg_endpos[no].lnum == reglnum)
  			{
  			    /* Compare back-ref within the current line. */
  			    len = reg_endpos[no].col - reg_startpos[no].col;
  			    if (cstrncmp(regline + reg_startpos[no].col,
  							  reginput, &len) != 0)
  				status = RA_NOMATCH;
  			}
  			else
  			{
  			    /* Messy situation: Need to compare between two
  			     * lines. */
  			    int r = match_with_backref(
  					    reg_startpos[no].lnum,
  					    reg_startpos[no].col,
  					    reg_endpos[no].lnum,
  					    reg_endpos[no].col,
  					    &len);
  
  			    if (r != RA_MATCH)
  				status = r;
  			}
  		    }
  		}
  
  		/* Matched the backref, skip over it. */
  		reginput += len;
  	    }
  	    break;
  
  #ifdef FEAT_SYN_HL
  	  case ZREF + 1:
  	  case ZREF + 2:
  	  case ZREF + 3:
  	  case ZREF + 4:
  	  case ZREF + 5:
  	  case ZREF + 6:
  	  case ZREF + 7:
  	  case ZREF + 8:
  	  case ZREF + 9:
  	    {
  		int	len;
  
  		cleanup_zsubexpr();
  		no = op - ZREF;
  		if (re_extmatch_in != NULL
  			&& re_extmatch_in->matches[no] != NULL)
  		{
  		    len = (int)STRLEN(re_extmatch_in->matches[no]);
  		    if (cstrncmp(re_extmatch_in->matches[no],
  							  reginput, &len) != 0)
  			status = RA_NOMATCH;
  		    else
  			reginput += len;
  		}
  		else
  		{
  		    /* Backref was not set: Match an empty string. */
  		}
  	    }
  	    break;
  #endif
  
  	  case BRANCH:
  	    {
  		if (OP(next) != BRANCH) /* No choice. */
  		    next = OPERAND(scan);	/* Avoid recursion. */
  		else
  		{
  		    rp = regstack_push(RS_BRANCH, scan);
  		    if (rp == NULL)
  			status = RA_FAIL;
  		    else
  			status = RA_BREAK;	/* rest is below */
  		}
  	    }
  	    break;
  
  	  case BRACE_LIMITS:
  	    {
  		if (OP(next) == BRACE_SIMPLE)
  		{
  		    bl_minval = OPERAND_MIN(scan);
  		    bl_maxval = OPERAND_MAX(scan);
  		}
  		else if (OP(next) >= BRACE_COMPLEX
  			&& OP(next) < BRACE_COMPLEX + 10)
  		{
  		    no = OP(next) - BRACE_COMPLEX;
  		    brace_min[no] = OPERAND_MIN(scan);
  		    brace_max[no] = OPERAND_MAX(scan);
  		    brace_count[no] = 0;
  		}
  		else
  		{
  		    EMSG(_(e_internal));	    /* Shouldn't happen */
  		    status = RA_FAIL;
  		}
  	    }
  	    break;
  
  	  case BRACE_COMPLEX + 0:
  	  case BRACE_COMPLEX + 1:
  	  case BRACE_COMPLEX + 2:
  	  case BRACE_COMPLEX + 3:
  	  case BRACE_COMPLEX + 4:
  	  case BRACE_COMPLEX + 5:
  	  case BRACE_COMPLEX + 6:
  	  case BRACE_COMPLEX + 7:
  	  case BRACE_COMPLEX + 8:
  	  case BRACE_COMPLEX + 9:
  	    {
  		no = op - BRACE_COMPLEX;
  		++brace_count[no];
  
  		/* If not matched enough times yet, try one more */
  		if (brace_count[no] <= (brace_min[no] <= brace_max[no]
  					     ? brace_min[no] : brace_max[no]))
  		{
  		    rp = regstack_push(RS_BRCPLX_MORE, scan);
  		    if (rp == NULL)
  			status = RA_FAIL;
  		    else
  		    {
  			rp->rs_no = no;
  			reg_save(&rp->rs_un.regsave, &backpos);
  			next = OPERAND(scan);
  			/* We continue and handle the result when done. */
  		    }
  		    break;
  		}
  
  		/* If matched enough times, may try matching some more */
  		if (brace_min[no] <= brace_max[no])
  		{
  		    /* Range is the normal way around, use longest match */
  		    if (brace_count[no] <= brace_max[no])
  		    {
  			rp = regstack_push(RS_BRCPLX_LONG, scan);
  			if (rp == NULL)
  			    status = RA_FAIL;
  			else
  			{
  			    rp->rs_no = no;
  			    reg_save(&rp->rs_un.regsave, &backpos);
  			    next = OPERAND(scan);
  			    /* We continue and handle the result when done. */
  			}
  		    }
  		}
  		else
  		{
  		    /* Range is backwards, use shortest match first */
  		    if (brace_count[no] <= brace_min[no])
  		    {
  			rp = regstack_push(RS_BRCPLX_SHORT, scan);
  			if (rp == NULL)
  			    status = RA_FAIL;
  			else
  			{
  			    reg_save(&rp->rs_un.regsave, &backpos);
  			    /* We continue and handle the result when done. */
  			}
  		    }
  		}
  	    }
  	    break;
  
  	  case BRACE_SIMPLE:
  	  case STAR:
  	  case PLUS:
  	    {
  		regstar_T	rst;
  
  		/*
  		 * Lookahead to avoid useless match attempts when we know
  		 * what character comes next.
  		 */
  		if (OP(next) == EXACTLY)
  		{
  		    rst.nextb = *OPERAND(next);
  		    if (ireg_ic)
  		    {
  			if (MB_ISUPPER(rst.nextb))
  			    rst.nextb_ic = MB_TOLOWER(rst.nextb);
  			else
  			    rst.nextb_ic = MB_TOUPPER(rst.nextb);
  		    }
  		    else
  			rst.nextb_ic = rst.nextb;
  		}
  		else
  		{
  		    rst.nextb = NUL;
  		    rst.nextb_ic = NUL;
  		}
  		if (op != BRACE_SIMPLE)
  		{
  		    rst.minval = (op == STAR) ? 0 : 1;
  		    rst.maxval = MAX_LIMIT;
  		}
  		else
  		{
  		    rst.minval = bl_minval;
  		    rst.maxval = bl_maxval;
  		}
  
  		/*
  		 * When maxval > minval, try matching as much as possible, up
  		 * to maxval.  When maxval < minval, try matching at least the
  		 * minimal number (since the range is backwards, that's also
  		 * maxval!).
  		 */
  		rst.count = regrepeat(OPERAND(scan), rst.maxval);
  		if (got_int)
  		{
  		    status = RA_FAIL;
  		    break;
  		}
  		if (rst.minval <= rst.maxval
  			  ? rst.count >= rst.minval : rst.count >= rst.maxval)
  		{
  		    /* It could match.  Prepare for trying to match what
  		     * follows.  The code is below.  Parameters are stored in
  		     * a regstar_T on the regstack. */
  		    if ((long)((unsigned)regstack.ga_len >> 10) >= p_mmp)
  		    {
  			EMSG(_(e_maxmempat));
  			status = RA_FAIL;
  		    }
  		    else if (ga_grow(&regstack, sizeof(regstar_T)) == FAIL)
  			status = RA_FAIL;
  		    else
  		    {
  			regstack.ga_len += sizeof(regstar_T);
  			rp = regstack_push(rst.minval <= rst.maxval
  					? RS_STAR_LONG : RS_STAR_SHORT, scan);
  			if (rp == NULL)
  			    status = RA_FAIL;
  			else
  			{
  			    *(((regstar_T *)rp) - 1) = rst;
  			    status = RA_BREAK;	    /* skip the restore bits */
  			}
  		    }
  		}
  		else
  		    status = RA_NOMATCH;
  
  	    }
  	    break;
  
  	  case NOMATCH:
  	  case MATCH:
  	  case SUBPAT:
  	    rp = regstack_push(RS_NOMATCH, scan);
  	    if (rp == NULL)
  		status = RA_FAIL;
  	    else
  	    {
  		rp->rs_no = op;
  		reg_save(&rp->rs_un.regsave, &backpos);
  		next = OPERAND(scan);
  		/* We continue and handle the result when done. */
  	    }
  	    break;
  
  	  case BEHIND:
  	  case NOBEHIND:
  	    /* Need a bit of room to store extra positions. */
  	    if ((long)((unsigned)regstack.ga_len >> 10) >= p_mmp)
  	    {
  		EMSG(_(e_maxmempat));
  		status = RA_FAIL;
  	    }
  	    else if (ga_grow(&regstack, sizeof(regbehind_T)) == FAIL)
  		status = RA_FAIL;
  	    else
  	    {
  		regstack.ga_len += sizeof(regbehind_T);
  		rp = regstack_push(RS_BEHIND1, scan);
  		if (rp == NULL)
  		    status = RA_FAIL;
  		else
  		{
  		    /* Need to save the subexpr to be able to restore them
  		     * when there is a match but we don't use it. */
  		    save_subexpr(((regbehind_T *)rp) - 1);
  
  		    rp->rs_no = op;
  		    reg_save(&rp->rs_un.regsave, &backpos);
  		    /* First try if what follows matches.  If it does then we
  		     * check the behind match by looping. */
  		}
  	    }
  	    break;
  
  	  case BHPOS:
  	    if (REG_MULTI)
  	    {
  		if (behind_pos.rs_u.pos.col != (colnr_T)(reginput - regline)
  			|| behind_pos.rs_u.pos.lnum != reglnum)
  		    status = RA_NOMATCH;
  	    }
  	    else if (behind_pos.rs_u.ptr != reginput)
  		status = RA_NOMATCH;
  	    break;
  
  	  case NEWL:
  	    if ((c != NUL || !REG_MULTI || reglnum > reg_maxline
  			     || reg_line_lbr) && (c != '\n' || !reg_line_lbr))
  		status = RA_NOMATCH;
  	    else if (reg_line_lbr)
  		ADVANCE_REGINPUT();
  	    else
  		reg_nextline();
  	    break;
  
  	  case END:
  	    status = RA_MATCH;	/* Success! */
  	    break;
  
  	  default:
  	    EMSG(_(e_re_corr));
  #ifdef DEBUG
  	    printf("Illegal op code %d\n", op);
  #endif
  	    status = RA_FAIL;
  	    break;
  	  }
  	}
  
  	/* If we can't continue sequentially, break the inner loop. */
  	if (status != RA_CONT)
  	    break;
  
  	/* Continue in inner loop, advance to next item. */
  	scan = next;
  
      } /* end of inner loop */
  
      /*
       * If there is something on the regstack execute the code for the state.
       * If the state is popped then loop and use the older state.
       */
      while (regstack.ga_len > 0 && status != RA_FAIL)
      {
  	rp = (regitem_T *)((char *)regstack.ga_data + regstack.ga_len) - 1;
  	switch (rp->rs_state)
  	{
  	  case RS_NOPEN:
  	    /* Result is passed on as-is, simply pop the state. */
  	    regstack_pop(&scan);
  	    break;
  
  	  case RS_MOPEN:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  		restore_se(&rp->rs_un.sesave, &reg_startpos[rp->rs_no],
  						  &reg_startp[rp->rs_no]);
  	    regstack_pop(&scan);
  	    break;
  
  #ifdef FEAT_SYN_HL
  	  case RS_ZOPEN:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  		restore_se(&rp->rs_un.sesave, &reg_startzpos[rp->rs_no],
  						 &reg_startzp[rp->rs_no]);
  	    regstack_pop(&scan);
  	    break;
  #endif
  
  	  case RS_MCLOSE:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  		restore_se(&rp->rs_un.sesave, &reg_endpos[rp->rs_no],
  						    &reg_endp[rp->rs_no]);
  	    regstack_pop(&scan);
  	    break;
  
  #ifdef FEAT_SYN_HL
  	  case RS_ZCLOSE:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  		restore_se(&rp->rs_un.sesave, &reg_endzpos[rp->rs_no],
  						   &reg_endzp[rp->rs_no]);
  	    regstack_pop(&scan);
  	    break;
  #endif
  
  	  case RS_BRANCH:
  	    if (status == RA_MATCH)
  		/* this branch matched, use it */
  		regstack_pop(&scan);
  	    else
  	    {
  		if (status != RA_BREAK)
  		{
  		    /* After a non-matching branch: try next one. */
  		    reg_restore(&rp->rs_un.regsave, &backpos);
  		    scan = rp->rs_scan;
  		}
  		if (scan == NULL || OP(scan) != BRANCH)
  		{
  		    /* no more branches, didn't find a match */
  		    status = RA_NOMATCH;
  		    regstack_pop(&scan);
  		}
  		else
  		{
  		    /* Prepare to try a branch. */
  		    rp->rs_scan = regnext(scan);
  		    reg_save(&rp->rs_un.regsave, &backpos);
  		    scan = OPERAND(scan);
  		}
  	    }
  	    break;
  
  	  case RS_BRCPLX_MORE:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  	    {
  		reg_restore(&rp->rs_un.regsave, &backpos);
  		--brace_count[rp->rs_no];	/* decrement match count */
  	    }
  	    regstack_pop(&scan);
  	    break;
  
  	  case RS_BRCPLX_LONG:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  	    {
  		/* There was no match, but we did find enough matches. */
  		reg_restore(&rp->rs_un.regsave, &backpos);
  		--brace_count[rp->rs_no];
  		/* continue with the items after "\{}" */
  		status = RA_CONT;
  	    }
  	    regstack_pop(&scan);
  	    if (status == RA_CONT)
  		scan = regnext(scan);
  	    break;
  
  	  case RS_BRCPLX_SHORT:
  	    /* Pop the state.  Restore pointers when there is no match. */
  	    if (status == RA_NOMATCH)
  		/* There was no match, try to match one more item. */
  		reg_restore(&rp->rs_un.regsave, &backpos);
  	    regstack_pop(&scan);
  	    if (status == RA_NOMATCH)
  	    {
  		scan = OPERAND(scan);
  		status = RA_CONT;
  	    }
  	    break;
  
  	  case RS_NOMATCH:
  	    /* Pop the state.  If the operand matches for NOMATCH or
  	     * doesn't match for MATCH/SUBPAT, we fail.  Otherwise backup,
  	     * except for SUBPAT, and continue with the next item. */
  	    if (status == (rp->rs_no == NOMATCH ? RA_MATCH : RA_NOMATCH))
  		status = RA_NOMATCH;
  	    else
  	    {
  		status = RA_CONT;
  		if (rp->rs_no != SUBPAT)	/* zero-width */
  		    reg_restore(&rp->rs_un.regsave, &backpos);
  	    }
  	    regstack_pop(&scan);
  	    if (status == RA_CONT)
  		scan = regnext(scan);
  	    break;
  
  	  case RS_BEHIND1:
  	    if (status == RA_NOMATCH)
  	    {
  		regstack_pop(&scan);
  		regstack.ga_len -= sizeof(regbehind_T);
  	    }
  	    else
  	    {
  		/* The stuff after BEHIND/NOBEHIND matches.  Now try if
  		 * the behind part does (not) match before the current
  		 * position in the input.  This must be done at every
  		 * position in the input and checking if the match ends at
  		 * the current position. */
  
  		/* save the position after the found match for next */
  		reg_save(&(((regbehind_T *)rp) - 1)->save_after, &backpos);
  
  		/* Start looking for a match with operand at the current
  		 * position.  Go back one character until we find the
  		 * result, hitting the start of the line or the previous
  		 * line (for multi-line matching).
  		 * Set behind_pos to where the match should end, BHPOS
  		 * will match it.  Save the current value. */
  		(((regbehind_T *)rp) - 1)->save_behind = behind_pos;
  		behind_pos = rp->rs_un.regsave;
  
  		rp->rs_state = RS_BEHIND2;
  
  		reg_restore(&rp->rs_un.regsave, &backpos);
  		scan = OPERAND(rp->rs_scan) + 4;
  	    }
  	    break;
  
  	  case RS_BEHIND2:
  	    /*
  	     * Looping for BEHIND / NOBEHIND match.
  	     */
  	    if (status == RA_MATCH && reg_save_equal(&behind_pos))
  	    {
  		/* found a match that ends where "next" started */
  		behind_pos = (((regbehind_T *)rp) - 1)->save_behind;
  		if (rp->rs_no == BEHIND)
  		    reg_restore(&(((regbehind_T *)rp) - 1)->save_after,
  								    &backpos);
  		else
  		{
  		    /* But we didn't want a match.  Need to restore the
  		     * subexpr, because what follows matched, so they have
  		     * been set. */
  		    status = RA_NOMATCH;
  		    restore_subexpr(((regbehind_T *)rp) - 1);
  		}
  		regstack_pop(&scan);
  		regstack.ga_len -= sizeof(regbehind_T);
  	    }
  	    else
  	    {
  		long limit;
  
  		/* No match or a match that doesn't end where we want it: Go
  		 * back one character.  May go to previous line once. */
  		no = OK;
  		limit = OPERAND_MIN(rp->rs_scan);
  		if (REG_MULTI)
  		{
  		    if (limit > 0
  			    && ((rp->rs_un.regsave.rs_u.pos.lnum
  						    < behind_pos.rs_u.pos.lnum
  				    ? (colnr_T)STRLEN(regline)
  				    : behind_pos.rs_u.pos.col)
  				- rp->rs_un.regsave.rs_u.pos.col >= limit))
  			no = FAIL;
  		    else if (rp->rs_un.regsave.rs_u.pos.col == 0)
  		    {
  			if (rp->rs_un.regsave.rs_u.pos.lnum
  					< behind_pos.rs_u.pos.lnum
  				|| reg_getline(
  					--rp->rs_un.regsave.rs_u.pos.lnum)
  								  == NULL)
  			    no = FAIL;
  			else
  			{
  			    reg_restore(&rp->rs_un.regsave, &backpos);
  			    rp->rs_un.regsave.rs_u.pos.col =
  						 (colnr_T)STRLEN(regline);
  			}
  		    }
  		    else
  		    {
  #ifdef FEAT_MBYTE
  			if (has_mbyte)
  			    rp->rs_un.regsave.rs_u.pos.col -=
  				(*mb_head_off)(regline, regline
  				    + rp->rs_un.regsave.rs_u.pos.col - 1) + 1;
  			else
  #endif
  			    --rp->rs_un.regsave.rs_u.pos.col;
  		    }
  		}
  		else
  		{
  		    if (rp->rs_un.regsave.rs_u.ptr == regline)
  			no = FAIL;
  		    else
  		    {
  			mb_ptr_back(regline, rp->rs_un.regsave.rs_u.ptr);
  			if (limit > 0 && (long)(behind_pos.rs_u.ptr
  				     - rp->rs_un.regsave.rs_u.ptr) > limit)
  			    no = FAIL;
  		    }
  		}
  		if (no == OK)
  		{
  		    /* Advanced, prepare for finding match again. */
  		    reg_restore(&rp->rs_un.regsave, &backpos);
  		    scan = OPERAND(rp->rs_scan) + 4;
  		    if (status == RA_MATCH)
  		    {
  			/* We did match, so subexpr may have been changed,
  			 * need to restore them for the next try. */
  			status = RA_NOMATCH;
  			restore_subexpr(((regbehind_T *)rp) - 1);
  		    }
  		}
  		else
  		{
  		    /* Can't advance.  For NOBEHIND that's a match. */
  		    behind_pos = (((regbehind_T *)rp) - 1)->save_behind;
  		    if (rp->rs_no == NOBEHIND)
  		    {
  			reg_restore(&(((regbehind_T *)rp) - 1)->save_after,
  								    &backpos);
  			status = RA_MATCH;
  		    }
  		    else
  		    {
  			/* We do want a proper match.  Need to restore the
  			 * subexpr if we had a match, because they may have
  			 * been set. */
  			if (status == RA_MATCH)
  			{
  			    status = RA_NOMATCH;
  			    restore_subexpr(((regbehind_T *)rp) - 1);
  			}
  		    }
  		    regstack_pop(&scan);
  		    regstack.ga_len -= sizeof(regbehind_T);
  		}
  	    }
  	    break;
  
  	  case RS_STAR_LONG:
  	  case RS_STAR_SHORT:
  	    {
  		regstar_T	    *rst = ((regstar_T *)rp) - 1;
  
  		if (status == RA_MATCH)
  		{
  		    regstack_pop(&scan);
  		    regstack.ga_len -= sizeof(regstar_T);
  		    break;
  		}
  
  		/* Tried once already, restore input pointers. */
  		if (status != RA_BREAK)
  		    reg_restore(&rp->rs_un.regsave, &backpos);
  
  		/* Repeat until we found a position where it could match. */
  		for (;;)
  		{
  		    if (status != RA_BREAK)
  		    {
  			/* Tried first position already, advance. */
  			if (rp->rs_state == RS_STAR_LONG)
  			{
  			    /* Trying for longest match, but couldn't or
  			     * didn't match -- back up one char. */
  			    if (--rst->count < rst->minval)
  				break;
  			    if (reginput == regline)
  			    {
  				/* backup to last char of previous line */
  				--reglnum;
  				regline = reg_getline(reglnum);
  				/* Just in case regrepeat() didn't count
  				 * right. */
  				if (regline == NULL)
  				    break;
  				reginput = regline + STRLEN(regline);
  				fast_breakcheck();
  			    }
  			    else
  				mb_ptr_back(regline, reginput);
  			}
  			else
  			{
  			    /* Range is backwards, use shortest match first.
  			     * Careful: maxval and minval are exchanged!
  			     * Couldn't or didn't match: try advancing one
  			     * char. */
  			    if (rst->count == rst->minval
  				  || regrepeat(OPERAND(rp->rs_scan), 1L) == 0)
  				break;
  			    ++rst->count;
  			}
  			if (got_int)
  			    break;
  		    }
  		    else
  			status = RA_NOMATCH;
  
  		    /* If it could match, try it. */
  		    if (rst->nextb == NUL || *reginput == rst->nextb
  					     || *reginput == rst->nextb_ic)
  		    {
  			reg_save(&rp->rs_un.regsave, &backpos);
  			scan = regnext(rp->rs_scan);
  			status = RA_CONT;
  			break;
  		    }
  		}
  		if (status != RA_CONT)
  		{
  		    /* Failed. */
  		    regstack_pop(&scan);
  		    regstack.ga_len -= sizeof(regstar_T);
  		    status = RA_NOMATCH;
  		}
  	    }
  	    break;
  	}
  
  	/* If we want to continue the inner loop or didn't pop a state
  	 * continue matching loop */
  	if (status == RA_CONT || rp == (regitem_T *)
  			     ((char *)regstack.ga_data + regstack.ga_len) - 1)
  	    break;
      }
  
      /* May need to continue with the inner loop, starting at "scan". */
      if (status == RA_CONT)
  	continue;
  
      /*
       * If the regstack is empty or something failed we are done.
       */
      if (regstack.ga_len == 0 || status == RA_FAIL)
      {
  	if (scan == NULL)
  	{
  	    /*
  	     * We get here only if there's trouble -- normally "case END" is
  	     * the terminating point.
  	     */
  	    EMSG(_(e_re_corr));
  #ifdef DEBUG
  	    printf("Premature EOL\n");
  #endif
  	}
  	if (status == RA_FAIL)
  	    got_int = TRUE;
  	return (status == RA_MATCH);
      }
  
    } /* End of loop until the regstack is empty. */
  
    /* NOTREACHED */
  }
  
  /*
   * Push an item onto the regstack.
   * Returns pointer to new item.  Returns NULL when out of memory.
   */
      static regitem_T *
  regstack_push(regstate_T state, char_u *scan)
  {
      regitem_T	*rp;
  
      if ((long)((unsigned)regstack.ga_len >> 10) >= p_mmp)
      {
  	EMSG(_(e_maxmempat));
  	return NULL;
      }
      if (ga_grow(&regstack, sizeof(regitem_T)) == FAIL)
  	return NULL;
  
      rp = (regitem_T *)((char *)regstack.ga_data + regstack.ga_len);
      rp->rs_state = state;
      rp->rs_scan = scan;
  
      regstack.ga_len += sizeof(regitem_T);
      return rp;
  }
  
  /*
   * Pop an item from the regstack.
   */
      static void
  regstack_pop(char_u **scan)
  {
      regitem_T	*rp;
  
      rp = (regitem_T *)((char *)regstack.ga_data + regstack.ga_len) - 1;
      *scan = rp->rs_scan;
  
      regstack.ga_len -= sizeof(regitem_T);
  }
  
  /*
   * regrepeat - repeatedly match something simple, return how many.
   * Advances reginput (and reglnum) to just after the matched chars.
   */
      static int
  regrepeat(
      char_u	*p,
      long	maxcount)   /* maximum number of matches allowed */
  {
      long	count = 0;
      char_u	*scan;
      char_u	*opnd;
      int		mask;
      int		testval = 0;
  
      scan = reginput;	    /* Make local copy of reginput for speed. */
      opnd = OPERAND(p);
      switch (OP(p))
      {
        case ANY:
        case ANY + ADD_NL:
  	while (count < maxcount)
  	{
  	    /* Matching anything means we continue until end-of-line (or
  	     * end-of-file for ANY + ADD_NL), only limited by maxcount. */
  	    while (*scan != NUL && count < maxcount)
  	    {
  		++count;
  		mb_ptr_adv(scan);
  	    }
  	    if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  					 || reg_line_lbr || count == maxcount)
  		break;
  	    ++count;		/* count the line-break */
  	    reg_nextline();
  	    scan = reginput;
  	    if (got_int)
  		break;
  	}
  	break;
  
        case IDENT:
        case IDENT + ADD_NL:
  	testval = TRUE;
  	/*FALLTHROUGH*/
        case SIDENT:
        case SIDENT + ADD_NL:
  	while (count < maxcount)
  	{
  	    if (vim_isIDc(PTR2CHAR(scan)) && (testval || !VIM_ISDIGIT(*scan)))
  	    {
  		mb_ptr_adv(scan);
  	    }
  	    else if (*scan == NUL)
  	    {
  		if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  							      || reg_line_lbr)
  		    break;
  		reg_nextline();
  		scan = reginput;
  		if (got_int)
  		    break;
  	    }
  	    else if (reg_line_lbr && *scan == '\n' && WITH_NL(OP(p)))
  		++scan;
  	    else
  		break;
  	    ++count;
  	}
  	break;
  
        case KWORD:
        case KWORD + ADD_NL:
  	testval = TRUE;
  	/*FALLTHROUGH*/
        case SKWORD:
        case SKWORD + ADD_NL:
  	while (count < maxcount)
  	{
  	    if (vim_iswordp_buf(scan, reg_buf)
  					  && (testval || !VIM_ISDIGIT(*scan)))
  	    {
  		mb_ptr_adv(scan);
  	    }
  	    else if (*scan == NUL)
  	    {
  		if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  							      || reg_line_lbr)
  		    break;
  		reg_nextline();
  		scan = reginput;
  		if (got_int)
  		    break;
  	    }
  	    else if (reg_line_lbr && *scan == '\n' && WITH_NL(OP(p)))
  		++scan;
  	    else
  		break;
  	    ++count;
  	}
  	break;
  
        case FNAME:
        case FNAME + ADD_NL:
  	testval = TRUE;
  	/*FALLTHROUGH*/
        case SFNAME:
        case SFNAME + ADD_NL:
  	while (count < maxcount)
  	{
  	    if (vim_isfilec(PTR2CHAR(scan)) && (testval || !VIM_ISDIGIT(*scan)))
  	    {
  		mb_ptr_adv(scan);
  	    }
  	    else if (*scan == NUL)
  	    {
  		if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  							      || reg_line_lbr)
  		    break;
  		reg_nextline();
  		scan = reginput;
  		if (got_int)
  		    break;
  	    }
  	    else if (reg_line_lbr && *scan == '\n' && WITH_NL(OP(p)))
  		++scan;
  	    else
  		break;
  	    ++count;
  	}
  	break;
  
        case PRINT:
        case PRINT + ADD_NL:
  	testval = TRUE;
  	/*FALLTHROUGH*/
        case SPRINT:
        case SPRINT + ADD_NL:
  	while (count < maxcount)
  	{
  	    if (*scan == NUL)
  	    {
  		if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  							      || reg_line_lbr)
  		    break;
  		reg_nextline();
  		scan = reginput;
  		if (got_int)
  		    break;
  	    }
  	    else if (vim_isprintc(PTR2CHAR(scan)) == 1
  					  && (testval || !VIM_ISDIGIT(*scan)))
  	    {
  		mb_ptr_adv(scan);
  	    }
  	    else if (reg_line_lbr && *scan == '\n' && WITH_NL(OP(p)))
  		++scan;
  	    else
  		break;
  	    ++count;
  	}
  	break;
  
        case WHITE:
        case WHITE + ADD_NL:
  	testval = mask = RI_WHITE;
  do_class:
  	while (count < maxcount)
  	{
  #ifdef FEAT_MBYTE
  	    int		l;
  #endif
  	    if (*scan == NUL)
  	    {
  		if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  							      || reg_line_lbr)
  		    break;
  		reg_nextline();
  		scan = reginput;
  		if (got_int)
  		    break;
  	    }
  #ifdef FEAT_MBYTE
  	    else if (has_mbyte && (l = (*mb_ptr2len)(scan)) > 1)
  	    {
  		if (testval != 0)
  		    break;
  		scan += l;
  	    }
  #endif
  	    else if ((class_tab[*scan] & mask) == testval)
  		++scan;
  	    else if (reg_line_lbr && *scan == '\n' && WITH_NL(OP(p)))
  		++scan;
  	    else
  		break;
  	    ++count;
  	}
  	break;
  
        case NWHITE:
        case NWHITE + ADD_NL:
  	mask = RI_WHITE;
  	goto do_class;
        case DIGIT:
        case DIGIT + ADD_NL:
  	testval = mask = RI_DIGIT;
  	goto do_class;
        case NDIGIT:
        case NDIGIT + ADD_NL:
  	mask = RI_DIGIT;
  	goto do_class;
        case HEX:
        case HEX + ADD_NL:
  	testval = mask = RI_HEX;
  	goto do_class;
        case NHEX:
        case NHEX + ADD_NL:
  	mask = RI_HEX;
  	goto do_class;
        case OCTAL:
        case OCTAL + ADD_NL:
  	testval = mask = RI_OCTAL;
  	goto do_class;
        case NOCTAL:
        case NOCTAL + ADD_NL:
  	mask = RI_OCTAL;
  	goto do_class;
        case WORD:
        case WORD + ADD_NL:
  	testval = mask = RI_WORD;
  	goto do_class;
        case NWORD:
        case NWORD + ADD_NL:
  	mask = RI_WORD;
  	goto do_class;
        case HEAD:
        case HEAD + ADD_NL:
  	testval = mask = RI_HEAD;
  	goto do_class;
        case NHEAD:
        case NHEAD + ADD_NL:
  	mask = RI_HEAD;
  	goto do_class;
        case ALPHA:
        case ALPHA + ADD_NL:
  	testval = mask = RI_ALPHA;
  	goto do_class;
        case NALPHA:
        case NALPHA + ADD_NL:
  	mask = RI_ALPHA;
  	goto do_class;
        case LOWER:
        case LOWER + ADD_NL:
  	testval = mask = RI_LOWER;
  	goto do_class;
        case NLOWER:
        case NLOWER + ADD_NL:
  	mask = RI_LOWER;
  	goto do_class;
        case UPPER:
        case UPPER + ADD_NL:
  	testval = mask = RI_UPPER;
  	goto do_class;
        case NUPPER:
        case NUPPER + ADD_NL:
  	mask = RI_UPPER;
  	goto do_class;
  
        case EXACTLY:
  	{
  	    int	    cu, cl;
  
  	    /* This doesn't do a multi-byte character, because a MULTIBYTECODE
  	     * would have been used for it.  It does handle single-byte
  	     * characters, such as latin1. */
  	    if (ireg_ic)
  	    {
  		cu = MB_TOUPPER(*opnd);
  		cl = MB_TOLOWER(*opnd);
  		while (count < maxcount && (*scan == cu || *scan == cl))
  		{
  		    count++;
  		    scan++;
  		}
  	    }
  	    else
  	    {
  		cu = *opnd;
  		while (count < maxcount && *scan == cu)
  		{
  		    count++;
  		    scan++;
  		}
  	    }
  	    break;
  	}
  
  #ifdef FEAT_MBYTE
        case MULTIBYTECODE:
  	{
  	    int		i, len, cf = 0;
  
  	    /* Safety check (just in case 'encoding' was changed since
  	     * compiling the program). */
  	    if ((len = (*mb_ptr2len)(opnd)) > 1)
  	    {
  		if (ireg_ic && enc_utf8)
  		    cf = utf_fold(utf_ptr2char(opnd));
  		while (count < maxcount && (*mb_ptr2len)(scan) >= len)
  		{
  		    for (i = 0; i < len; ++i)
  			if (opnd[i] != scan[i])
  			    break;
  		    if (i < len && (!ireg_ic || !enc_utf8
  					|| utf_fold(utf_ptr2char(scan)) != cf))
  			break;
  		    scan += len;
  		    ++count;
  		}
  	    }
  	}
  	break;
  #endif
  
        case ANYOF:
        case ANYOF + ADD_NL:
  	testval = TRUE;
  	/*FALLTHROUGH*/
  
        case ANYBUT:
        case ANYBUT + ADD_NL:
  	while (count < maxcount)
  	{
  #ifdef FEAT_MBYTE
  	    int len;
  #endif
  	    if (*scan == NUL)
  	    {
  		if (!REG_MULTI || !WITH_NL(OP(p)) || reglnum > reg_maxline
  							      || reg_line_lbr)
  		    break;
  		reg_nextline();
  		scan = reginput;
  		if (got_int)
  		    break;
  	    }
  	    else if (reg_line_lbr && *scan == '\n' && WITH_NL(OP(p)))
  		++scan;
  #ifdef FEAT_MBYTE
  	    else if (has_mbyte && (len = (*mb_ptr2len)(scan)) > 1)
  	    {
  		if ((cstrchr(opnd, (*mb_ptr2char)(scan)) == NULL) == testval)
  		    break;
  		scan += len;
  	    }
  #endif
  	    else
  	    {
  		if ((cstrchr(opnd, *scan) == NULL) == testval)
  		    break;
  		++scan;
  	    }
  	    ++count;
  	}
  	break;
  
        case NEWL:
  	while (count < maxcount
  		&& ((*scan == NUL && reglnum <= reg_maxline && !reg_line_lbr
  			    && REG_MULTI) || (*scan == '\n' && reg_line_lbr)))
  	{
  	    count++;
  	    if (reg_line_lbr)
  		ADVANCE_REGINPUT();
  	    else
  		reg_nextline();
  	    scan = reginput;
  	    if (got_int)
  		break;
  	}
  	break;
  
        default:			/* Oh dear.  Called inappropriately. */
  	EMSG(_(e_re_corr));
  #ifdef DEBUG
  	printf("Called regrepeat with op code %d\n", OP(p));
  #endif
  	break;
      }
  
      reginput = scan;
  
      return (int)count;
  }
  
  /*
   * regnext - dig the "next" pointer out of a node
   * Returns NULL when calculating size, when there is no next item and when
   * there is an error.
   */
      static char_u *
  regnext(char_u *p)
  {
      int	    offset;
  
      if (p == JUST_CALC_SIZE || reg_toolong)
  	return NULL;
  
      offset = NEXT(p);
      if (offset == 0)
  	return NULL;
  
      if (OP(p) == BACK)
  	return p - offset;
      else
  	return p + offset;
  }
  
  /*
   * Check the regexp program for its magic number.
   * Return TRUE if it's wrong.
   */
      static int
  prog_magic_wrong(void)
  {
      regprog_T	*prog;
  
      prog = REG_MULTI ? reg_mmatch->regprog : reg_match->regprog;
      if (prog->engine == &nfa_regengine)
  	/* For NFA matcher we don't check the magic */
  	return FALSE;
  
      if (UCHARAT(((bt_regprog_T *)prog)->program) != REGMAGIC)
      {
  	EMSG(_(e_re_corr));
  	return TRUE;
      }
      return FALSE;
  }
  
  /*
   * Cleanup the subexpressions, if this wasn't done yet.
   * This construction is used to clear the subexpressions only when they are
   * used (to increase speed).
   */
      static void
  cleanup_subexpr(void)
  {
      if (need_clear_subexpr)
      {
  	if (REG_MULTI)
  	{
  	    /* Use 0xff to set lnum to -1 */
  	    vim_memset(reg_startpos, 0xff, sizeof(lpos_T) * NSUBEXP);
  	    vim_memset(reg_endpos, 0xff, sizeof(lpos_T) * NSUBEXP);
  	}
  	else
  	{
  	    vim_memset(reg_startp, 0, sizeof(char_u *) * NSUBEXP);
  	    vim_memset(reg_endp, 0, sizeof(char_u *) * NSUBEXP);
  	}
  	need_clear_subexpr = FALSE;
      }
  }
  
  #ifdef FEAT_SYN_HL
      static void
  cleanup_zsubexpr(void)
  {
      if (need_clear_zsubexpr)
      {
  	if (REG_MULTI)
  	{
  	    /* Use 0xff to set lnum to -1 */
  	    vim_memset(reg_startzpos, 0xff, sizeof(lpos_T) * NSUBEXP);
  	    vim_memset(reg_endzpos, 0xff, sizeof(lpos_T) * NSUBEXP);
  	}
  	else
  	{
  	    vim_memset(reg_startzp, 0, sizeof(char_u *) * NSUBEXP);
  	    vim_memset(reg_endzp, 0, sizeof(char_u *) * NSUBEXP);
  	}
  	need_clear_zsubexpr = FALSE;
      }
  }
  #endif
  
  /*
   * Save the current subexpr to "bp", so that they can be restored
   * later by restore_subexpr().
   */
      static void
  save_subexpr(regbehind_T *bp)
  {
      int i;
  
      /* When "need_clear_subexpr" is set we don't need to save the values, only
       * remember that this flag needs to be set again when restoring. */
      bp->save_need_clear_subexpr = need_clear_subexpr;
      if (!need_clear_subexpr)
      {
  	for (i = 0; i < NSUBEXP; ++i)
  	{
  	    if (REG_MULTI)
  	    {
  		bp->save_start[i].se_u.pos = reg_startpos[i];
  		bp->save_end[i].se_u.pos = reg_endpos[i];
  	    }
  	    else
  	    {
  		bp->save_start[i].se_u.ptr = reg_startp[i];
  		bp->save_end[i].se_u.ptr = reg_endp[i];
  	    }
  	}
      }
  }
  
  /*
   * Restore the subexpr from "bp".
   */
      static void
  restore_subexpr(regbehind_T *bp)
  {
      int i;
  
      /* Only need to restore saved values when they are not to be cleared. */
      need_clear_subexpr = bp->save_need_clear_subexpr;
      if (!need_clear_subexpr)
      {
  	for (i = 0; i < NSUBEXP; ++i)
  	{
  	    if (REG_MULTI)
  	    {
  		reg_startpos[i] = bp->save_start[i].se_u.pos;
  		reg_endpos[i] = bp->save_end[i].se_u.pos;
  	    }
  	    else
  	    {
  		reg_startp[i] = bp->save_start[i].se_u.ptr;
  		reg_endp[i] = bp->save_end[i].se_u.ptr;
  	    }
  	}
      }
  }
  
  /*
   * Advance reglnum, regline and reginput to the next line.
   */
      static void
  reg_nextline(void)
  {
      regline = reg_getline(++reglnum);
      reginput = regline;
      fast_breakcheck();
  }
  
  /*
   * Save the input line and position in a regsave_T.
   */
      static void
  reg_save(regsave_T *save, garray_T *gap)
  {
      if (REG_MULTI)
      {
  	save->rs_u.pos.col = (colnr_T)(reginput - regline);
  	save->rs_u.pos.lnum = reglnum;
      }
      else
  	save->rs_u.ptr = reginput;
      save->rs_len = gap->ga_len;
  }
  
  /*
   * Restore the input line and position from a regsave_T.
   */
      static void
  reg_restore(regsave_T *save, garray_T *gap)
  {
      if (REG_MULTI)
      {
  	if (reglnum != save->rs_u.pos.lnum)
  	{
  	    /* only call reg_getline() when the line number changed to save
  	     * a bit of time */
  	    reglnum = save->rs_u.pos.lnum;
  	    regline = reg_getline(reglnum);
  	}
  	reginput = regline + save->rs_u.pos.col;
      }
      else
  	reginput = save->rs_u.ptr;
      gap->ga_len = save->rs_len;
  }
  
  /*
   * Return TRUE if current position is equal to saved position.
   */
      static int
  reg_save_equal(regsave_T *save)
  {
      if (REG_MULTI)
  	return reglnum == save->rs_u.pos.lnum
  				  && reginput == regline + save->rs_u.pos.col;
      return reginput == save->rs_u.ptr;
  }
  
  /*
   * Tentatively set the sub-expression start to the current position (after
   * calling regmatch() they will have changed).  Need to save the existing
   * values for when there is no match.
   * Use se_save() to use pointer (save_se_multi()) or position (save_se_one()),
   * depending on REG_MULTI.
   */
      static void
  save_se_multi(save_se_T *savep, lpos_T *posp)
  {
      savep->se_u.pos = *posp;
      posp->lnum = reglnum;
      posp->col = (colnr_T)(reginput - regline);
  }
  
      static void
  save_se_one(save_se_T *savep, char_u **pp)
  {
      savep->se_u.ptr = *pp;
      *pp = reginput;
  }
  
  /*
   * Compare a number with the operand of RE_LNUM, RE_COL or RE_VCOL.
   */
      static int
  re_num_cmp(long_u val, char_u *scan)
  {
      long_u  n = OPERAND_MIN(scan);
  
      if (OPERAND_CMP(scan) == '>')
  	return val > n;
      if (OPERAND_CMP(scan) == '<')
  	return val < n;
      return val == n;
  }
  
  /*
   * Check whether a backreference matches.
   * Returns RA_FAIL, RA_NOMATCH or RA_MATCH.
   * If "bytelen" is not NULL, it is set to the byte length of the match in the
   * last line.
   */
      static int
  match_with_backref(
      linenr_T start_lnum,
      colnr_T  start_col,
      linenr_T end_lnum,
      colnr_T  end_col,
      int	     *bytelen)
  {
      linenr_T	clnum = start_lnum;
      colnr_T	ccol = start_col;
      int		len;
      char_u	*p;
  
      if (bytelen != NULL)
  	*bytelen = 0;
      for (;;)
      {
  	/* Since getting one line may invalidate the other, need to make copy.
  	 * Slow! */
  	if (regline != reg_tofree)
  	{
  	    len = (int)STRLEN(regline);
  	    if (reg_tofree == NULL || len >= (int)reg_tofreelen)
  	    {
  		len += 50;	/* get some extra */
  		vim_free(reg_tofree);
  		reg_tofree = alloc(len);
  		if (reg_tofree == NULL)
  		    return RA_FAIL; /* out of memory!*/
  		reg_tofreelen = len;
  	    }
  	    STRCPY(reg_tofree, regline);
  	    reginput = reg_tofree + (reginput - regline);
  	    regline = reg_tofree;
  	}
  
  	/* Get the line to compare with. */
  	p = reg_getline(clnum);
  	if (clnum == end_lnum)
  	    len = end_col - ccol;
  	else
  	    len = (int)STRLEN(p + ccol);
  
  	if (cstrncmp(p + ccol, reginput, &len) != 0)
  	    return RA_NOMATCH;  /* doesn't match */
  	if (bytelen != NULL)
  	    *bytelen += len;
  	if (clnum == end_lnum)
  	    break;		/* match and at end! */
  	if (reglnum >= reg_maxline)
  	    return RA_NOMATCH;  /* text too short */
  
  	/* Advance to next line. */
  	reg_nextline();
  	if (bytelen != NULL)
  	    *bytelen = 0;
  	++clnum;
  	ccol = 0;
  	if (got_int)
  	    return RA_FAIL;
      }
  
      /* found a match!  Note that regline may now point to a copy of the line,
       * that should not matter. */
      return RA_MATCH;
  }
  
  #ifdef BT_REGEXP_DUMP
  
  /*
   * regdump - dump a regexp onto stdout in vaguely comprehensible form
   */
      static void
  regdump(char_u *pattern, bt_regprog_T *r)
  {
      char_u  *s;
      int	    op = EXACTLY;	/* Arbitrary non-END op. */
      char_u  *next;
      char_u  *end = NULL;
      FILE    *f;
  
  #ifdef BT_REGEXP_LOG
      f = fopen("bt_regexp_log.log", "a");
  #else
      f = stdout;
  #endif
      if (f == NULL)
  	return;
      fprintf(f, "-------------------------------------\n\r\nregcomp(%s):\r\n", pattern);
  
      s = r->program + 1;
      /*
       * Loop until we find the END that isn't before a referred next (an END
       * can also appear in a NOMATCH operand).
       */
      while (op != END || s <= end)
      {
  	op = OP(s);
  	fprintf(f, "%2d%s", (int)(s - r->program), regprop(s)); /* Where, what. */
  	next = regnext(s);
  	if (next == NULL)	/* Next ptr. */
  	    fprintf(f, "(0)");
  	else
  	    fprintf(f, "(%d)", (int)((s - r->program) + (next - s)));
  	if (end < next)
  	    end = next;
  	if (op == BRACE_LIMITS)
  	{
  	    /* Two ints */
  	    fprintf(f, " minval %ld, maxval %ld", OPERAND_MIN(s), OPERAND_MAX(s));
  	    s += 8;
  	}
  	else if (op == BEHIND || op == NOBEHIND)
  	{
  	    /* one int */
  	    fprintf(f, " count %ld", OPERAND_MIN(s));
  	    s += 4;
  	}
  	else if (op == RE_LNUM || op == RE_COL || op == RE_VCOL)
  	{
  	    /* one int plus comperator */
  	    fprintf(f, " count %ld", OPERAND_MIN(s));
  	    s += 5;
  	}
  	s += 3;
  	if (op == ANYOF || op == ANYOF + ADD_NL
  		|| op == ANYBUT || op == ANYBUT + ADD_NL
  		|| op == EXACTLY)
  	{
  	    /* Literal string, where present. */
  	    fprintf(f, "\nxxxxxxxxx\n");
  	    while (*s != NUL)
  		fprintf(f, "%c", *s++);
  	    fprintf(f, "\nxxxxxxxxx\n");
  	    s++;
  	}
  	fprintf(f, "\r\n");
      }
  
      /* Header fields of interest. */
      if (r->regstart != NUL)
  	fprintf(f, "start `%s' 0x%x; ", r->regstart < 256
  		? (char *)transchar(r->regstart)
  		: "multibyte", r->regstart);
      if (r->reganch)
  	fprintf(f, "anchored; ");
      if (r->regmust != NULL)
  	fprintf(f, "must have \"%s\"", r->regmust);
      fprintf(f, "\r\n");
  
  #ifdef BT_REGEXP_LOG
      fclose(f);
  #endif
  }
  #endif	    /* BT_REGEXP_DUMP */
  
  #ifdef DEBUG
  /*
   * regprop - printable representation of opcode
   */
      static char_u *
  regprop(char_u *op)
  {
      char	    *p;
      static char	    buf[50];
  
      STRCPY(buf, ":");
  
      switch ((int) OP(op))
      {
        case BOL:
  	p = "BOL";
  	break;
        case EOL:
  	p = "EOL";
  	break;
        case RE_BOF:
  	p = "BOF";
  	break;
        case RE_EOF:
  	p = "EOF";
  	break;
        case CURSOR:
  	p = "CURSOR";
  	break;
        case RE_VISUAL:
  	p = "RE_VISUAL";
  	break;
        case RE_LNUM:
  	p = "RE_LNUM";
  	break;
        case RE_MARK:
  	p = "RE_MARK";
  	break;
        case RE_COL:
  	p = "RE_COL";
  	break;
        case RE_VCOL:
  	p = "RE_VCOL";
  	break;
        case BOW:
  	p = "BOW";
  	break;
        case EOW:
  	p = "EOW";
  	break;
        case ANY:
  	p = "ANY";
  	break;
        case ANY + ADD_NL:
  	p = "ANY+NL";
  	break;
        case ANYOF:
  	p = "ANYOF";
  	break;
        case ANYOF + ADD_NL:
  	p = "ANYOF+NL";
  	break;
        case ANYBUT:
  	p = "ANYBUT";
  	break;
        case ANYBUT + ADD_NL:
  	p = "ANYBUT+NL";
  	break;
        case IDENT:
  	p = "IDENT";
  	break;
        case IDENT + ADD_NL:
  	p = "IDENT+NL";
  	break;
        case SIDENT:
  	p = "SIDENT";
  	break;
        case SIDENT + ADD_NL:
  	p = "SIDENT+NL";
  	break;
        case KWORD:
  	p = "KWORD";
  	break;
        case KWORD + ADD_NL:
  	p = "KWORD+NL";
  	break;
        case SKWORD:
  	p = "SKWORD";
  	break;
        case SKWORD + ADD_NL:
  	p = "SKWORD+NL";
  	break;
        case FNAME:
  	p = "FNAME";
  	break;
        case FNAME + ADD_NL:
  	p = "FNAME+NL";
  	break;
        case SFNAME:
  	p = "SFNAME";
  	break;
        case SFNAME + ADD_NL:
  	p = "SFNAME+NL";
  	break;
        case PRINT:
  	p = "PRINT";
  	break;
        case PRINT + ADD_NL:
  	p = "PRINT+NL";
  	break;
        case SPRINT:
  	p = "SPRINT";
  	break;
        case SPRINT + ADD_NL:
  	p = "SPRINT+NL";
  	break;
        case WHITE:
  	p = "WHITE";
  	break;
        case WHITE + ADD_NL:
  	p = "WHITE+NL";
  	break;
        case NWHITE:
  	p = "NWHITE";
  	break;
        case NWHITE + ADD_NL:
  	p = "NWHITE+NL";
  	break;
        case DIGIT:
  	p = "DIGIT";
  	break;
        case DIGIT + ADD_NL:
  	p = "DIGIT+NL";
  	break;
        case NDIGIT:
  	p = "NDIGIT";
  	break;
        case NDIGIT + ADD_NL:
  	p = "NDIGIT+NL";
  	break;
        case HEX:
  	p = "HEX";
  	break;
        case HEX + ADD_NL:
  	p = "HEX+NL";
  	break;
        case NHEX:
  	p = "NHEX";
  	break;
        case NHEX + ADD_NL:
  	p = "NHEX+NL";
  	break;
        case OCTAL:
  	p = "OCTAL";
  	break;
        case OCTAL + ADD_NL:
  	p = "OCTAL+NL";
  	break;
        case NOCTAL:
  	p = "NOCTAL";
  	break;
        case NOCTAL + ADD_NL:
  	p = "NOCTAL+NL";
  	break;
        case WORD:
  	p = "WORD";
  	break;
        case WORD + ADD_NL:
  	p = "WORD+NL";
  	break;
        case NWORD:
  	p = "NWORD";
  	break;
        case NWORD + ADD_NL:
  	p = "NWORD+NL";
  	break;
        case HEAD:
  	p = "HEAD";
  	break;
        case HEAD + ADD_NL:
  	p = "HEAD+NL";
  	break;
        case NHEAD:
  	p = "NHEAD";
  	break;
        case NHEAD + ADD_NL:
  	p = "NHEAD+NL";
  	break;
        case ALPHA:
  	p = "ALPHA";
  	break;
        case ALPHA + ADD_NL:
  	p = "ALPHA+NL";
  	break;
        case NALPHA:
  	p = "NALPHA";
  	break;
        case NALPHA + ADD_NL:
  	p = "NALPHA+NL";
  	break;
        case LOWER:
  	p = "LOWER";
  	break;
        case LOWER + ADD_NL:
  	p = "LOWER+NL";
  	break;
        case NLOWER:
  	p = "NLOWER";
  	break;
        case NLOWER + ADD_NL:
  	p = "NLOWER+NL";
  	break;
        case UPPER:
  	p = "UPPER";
  	break;
        case UPPER + ADD_NL:
  	p = "UPPER+NL";
  	break;
        case NUPPER:
  	p = "NUPPER";
  	break;
        case NUPPER + ADD_NL:
  	p = "NUPPER+NL";
  	break;
        case BRANCH:
  	p = "BRANCH";
  	break;
        case EXACTLY:
  	p = "EXACTLY";
  	break;
        case NOTHING:
  	p = "NOTHING";
  	break;
        case BACK:
  	p = "BACK";
  	break;
        case END:
  	p = "END";
  	break;
        case MOPEN + 0:
  	p = "MATCH START";
  	break;
        case MOPEN + 1:
        case MOPEN + 2:
        case MOPEN + 3:
        case MOPEN + 4:
        case MOPEN + 5:
        case MOPEN + 6:
        case MOPEN + 7:
        case MOPEN + 8:
        case MOPEN + 9:
  	sprintf(buf + STRLEN(buf), "MOPEN%d", OP(op) - MOPEN);
  	p = NULL;
  	break;
        case MCLOSE + 0:
  	p = "MATCH END";
  	break;
        case MCLOSE + 1:
        case MCLOSE + 2:
        case MCLOSE + 3:
        case MCLOSE + 4:
        case MCLOSE + 5:
        case MCLOSE + 6:
        case MCLOSE + 7:
        case MCLOSE + 8:
        case MCLOSE + 9:
  	sprintf(buf + STRLEN(buf), "MCLOSE%d", OP(op) - MCLOSE);
  	p = NULL;
  	break;
        case BACKREF + 1:
        case BACKREF + 2:
        case BACKREF + 3:
        case BACKREF + 4:
        case BACKREF + 5:
        case BACKREF + 6:
        case BACKREF + 7:
        case BACKREF + 8:
        case BACKREF + 9:
  	sprintf(buf + STRLEN(buf), "BACKREF%d", OP(op) - BACKREF);
  	p = NULL;
  	break;
        case NOPEN:
  	p = "NOPEN";
  	break;
        case NCLOSE:
  	p = "NCLOSE";
  	break;
  #ifdef FEAT_SYN_HL
        case ZOPEN + 1:
        case ZOPEN + 2:
        case ZOPEN + 3:
        case ZOPEN + 4:
        case ZOPEN + 5:
        case ZOPEN + 6:
        case ZOPEN + 7:
        case ZOPEN + 8:
        case ZOPEN + 9:
  	sprintf(buf + STRLEN(buf), "ZOPEN%d", OP(op) - ZOPEN);
  	p = NULL;
  	break;
        case ZCLOSE + 1:
        case ZCLOSE + 2:
        case ZCLOSE + 3:
        case ZCLOSE + 4:
        case ZCLOSE + 5:
        case ZCLOSE + 6:
        case ZCLOSE + 7:
        case ZCLOSE + 8:
        case ZCLOSE + 9:
  	sprintf(buf + STRLEN(buf), "ZCLOSE%d", OP(op) - ZCLOSE);
  	p = NULL;
  	break;
        case ZREF + 1:
        case ZREF + 2:
        case ZREF + 3:
        case ZREF + 4:
        case ZREF + 5:
        case ZREF + 6:
        case ZREF + 7:
        case ZREF + 8:
        case ZREF + 9:
  	sprintf(buf + STRLEN(buf), "ZREF%d", OP(op) - ZREF);
  	p = NULL;
  	break;
  #endif
        case STAR:
  	p = "STAR";
  	break;
        case PLUS:
  	p = "PLUS";
  	break;
        case NOMATCH:
  	p = "NOMATCH";
  	break;
        case MATCH:
  	p = "MATCH";
  	break;
        case BEHIND:
  	p = "BEHIND";
  	break;
        case NOBEHIND:
  	p = "NOBEHIND";
  	break;
        case SUBPAT:
  	p = "SUBPAT";
  	break;
        case BRACE_LIMITS:
  	p = "BRACE_LIMITS";
  	break;
        case BRACE_SIMPLE:
  	p = "BRACE_SIMPLE";
  	break;
        case BRACE_COMPLEX + 0:
        case BRACE_COMPLEX + 1:
        case BRACE_COMPLEX + 2:
        case BRACE_COMPLEX + 3:
        case BRACE_COMPLEX + 4:
        case BRACE_COMPLEX + 5:
        case BRACE_COMPLEX + 6:
        case BRACE_COMPLEX + 7:
        case BRACE_COMPLEX + 8:
        case BRACE_COMPLEX + 9:
  	sprintf(buf + STRLEN(buf), "BRACE_COMPLEX%d", OP(op) - BRACE_COMPLEX);
  	p = NULL;
  	break;
  #ifdef FEAT_MBYTE
        case MULTIBYTECODE:
  	p = "MULTIBYTECODE";
  	break;
  #endif
        case NEWL:
  	p = "NEWL";
  	break;
        default:
  	sprintf(buf + STRLEN(buf), "corrupt %d", OP(op));
  	p = NULL;
  	break;
      }
      if (p != NULL)
  	STRCAT(buf, p);
      return (char_u *)buf;
  }
  #endif	    /* DEBUG */
  
  /*
   * Used in a place where no * or \+ can follow.
   */
      static int
  re_mult_next(char *what)
  {
      if (re_multi_type(peekchr()) == MULTI_MULT)
  	EMSG2_RET_FAIL(_("E888: (NFA regexp) cannot repeat %s"), what);
      return OK;
  }
  
  #ifdef FEAT_MBYTE
  static void mb_decompose(int c, int *c1, int *c2, int *c3);
  
  typedef struct
  {
      int a, b, c;
  } decomp_T;
  
  
  /* 0xfb20 - 0xfb4f */
  static decomp_T decomp_table[0xfb4f-0xfb20+1] =
  {
      {0x5e2,0,0},		/* 0xfb20	alt ayin */
      {0x5d0,0,0},		/* 0xfb21	alt alef */
      {0x5d3,0,0},		/* 0xfb22	alt dalet */
      {0x5d4,0,0},		/* 0xfb23	alt he */
      {0x5db,0,0},		/* 0xfb24	alt kaf */
      {0x5dc,0,0},		/* 0xfb25	alt lamed */
      {0x5dd,0,0},		/* 0xfb26	alt mem-sofit */
      {0x5e8,0,0},		/* 0xfb27	alt resh */
      {0x5ea,0,0},		/* 0xfb28	alt tav */
      {'+', 0, 0},		/* 0xfb29	alt plus */
      {0x5e9, 0x5c1, 0},		/* 0xfb2a	shin+shin-dot */
      {0x5e9, 0x5c2, 0},		/* 0xfb2b	shin+sin-dot */
      {0x5e9, 0x5c1, 0x5bc},	/* 0xfb2c	shin+shin-dot+dagesh */
      {0x5e9, 0x5c2, 0x5bc},	/* 0xfb2d	shin+sin-dot+dagesh */
      {0x5d0, 0x5b7, 0},		/* 0xfb2e	alef+patah */
      {0x5d0, 0x5b8, 0},		/* 0xfb2f	alef+qamats */
      {0x5d0, 0x5b4, 0},		/* 0xfb30	alef+hiriq */
      {0x5d1, 0x5bc, 0},		/* 0xfb31	bet+dagesh */
      {0x5d2, 0x5bc, 0},		/* 0xfb32	gimel+dagesh */
      {0x5d3, 0x5bc, 0},		/* 0xfb33	dalet+dagesh */
      {0x5d4, 0x5bc, 0},		/* 0xfb34	he+dagesh */
      {0x5d5, 0x5bc, 0},		/* 0xfb35	vav+dagesh */
      {0x5d6, 0x5bc, 0},		/* 0xfb36	zayin+dagesh */
      {0xfb37, 0, 0},		/* 0xfb37 -- UNUSED */
      {0x5d8, 0x5bc, 0},		/* 0xfb38	tet+dagesh */
      {0x5d9, 0x5bc, 0},		/* 0xfb39	yud+dagesh */
      {0x5da, 0x5bc, 0},		/* 0xfb3a	kaf sofit+dagesh */
      {0x5db, 0x5bc, 0},		/* 0xfb3b	kaf+dagesh */
      {0x5dc, 0x5bc, 0},		/* 0xfb3c	lamed+dagesh */
      {0xfb3d, 0, 0},		/* 0xfb3d -- UNUSED */
      {0x5de, 0x5bc, 0},		/* 0xfb3e	mem+dagesh */
      {0xfb3f, 0, 0},		/* 0xfb3f -- UNUSED */
      {0x5e0, 0x5bc, 0},		/* 0xfb40	nun+dagesh */
      {0x5e1, 0x5bc, 0},		/* 0xfb41	samech+dagesh */
      {0xfb42, 0, 0},		/* 0xfb42 -- UNUSED */
      {0x5e3, 0x5bc, 0},		/* 0xfb43	pe sofit+dagesh */
      {0x5e4, 0x5bc,0},		/* 0xfb44	pe+dagesh */
      {0xfb45, 0, 0},		/* 0xfb45 -- UNUSED */
      {0x5e6, 0x5bc, 0},		/* 0xfb46	tsadi+dagesh */
      {0x5e7, 0x5bc, 0},		/* 0xfb47	qof+dagesh */
      {0x5e8, 0x5bc, 0},		/* 0xfb48	resh+dagesh */
      {0x5e9, 0x5bc, 0},		/* 0xfb49	shin+dagesh */
      {0x5ea, 0x5bc, 0},		/* 0xfb4a	tav+dagesh */
      {0x5d5, 0x5b9, 0},		/* 0xfb4b	vav+holam */
      {0x5d1, 0x5bf, 0},		/* 0xfb4c	bet+rafe */
      {0x5db, 0x5bf, 0},		/* 0xfb4d	kaf+rafe */
      {0x5e4, 0x5bf, 0},		/* 0xfb4e	pe+rafe */
      {0x5d0, 0x5dc, 0}		/* 0xfb4f	alef-lamed */
  };
  
      static void
  mb_decompose(int c, int *c1, int *c2, int *c3)
  {
      decomp_T d;
  
      if (c >= 0xfb20 && c <= 0xfb4f)
      {
  	d = decomp_table[c - 0xfb20];
  	*c1 = d.a;
  	*c2 = d.b;
  	*c3 = d.c;
      }
      else
      {
  	*c1 = c;
  	*c2 = *c3 = 0;
      }
  }
  #endif
  
  /*
   * Compare two strings, ignore case if ireg_ic set.
   * Return 0 if strings match, non-zero otherwise.
   * Correct the length "*n" when composing characters are ignored.
   */
      static int
  cstrncmp(char_u *s1, char_u *s2, int *n)
  {
      int		result;
  
      if (!ireg_ic)
  	result = STRNCMP(s1, s2, *n);
      else
  	result = MB_STRNICMP(s1, s2, *n);
  
  #ifdef FEAT_MBYTE
      /* if it failed and it's utf8 and we want to combineignore: */
      if (result != 0 && enc_utf8 && ireg_icombine)
      {
  	char_u	*str1, *str2;
  	int	c1, c2, c11, c12;
  	int	junk;
  
  	/* we have to handle the strcmp ourselves, since it is necessary to
  	 * deal with the composing characters by ignoring them: */
  	str1 = s1;
  	str2 = s2;
  	c1 = c2 = 0;
  	while ((int)(str1 - s1) < *n)
  	{
  	    c1 = mb_ptr2char_adv(&str1);
  	    c2 = mb_ptr2char_adv(&str2);
  
  	    /* decompose the character if necessary, into 'base' characters
  	     * because I don't care about Arabic, I will hard-code the Hebrew
  	     * which I *do* care about!  So sue me... */
  	    if (c1 != c2 && (!ireg_ic || utf_fold(c1) != utf_fold(c2)))
  	    {
  		/* decomposition necessary? */
  		mb_decompose(c1, &c11, &junk, &junk);
  		mb_decompose(c2, &c12, &junk, &junk);
  		c1 = c11;
  		c2 = c12;
  		if (c11 != c12 && (!ireg_ic || utf_fold(c11) != utf_fold(c12)))
  		    break;
  	    }
  	}
  	result = c2 - c1;
  	if (result == 0)
  	    *n = (int)(str2 - s2);
      }
  #endif
  
      return result;
  }
  
  /*
   * cstrchr: This function is used a lot for simple searches, keep it fast!
   */
      static char_u *
  cstrchr(char_u *s, int c)
  {
      char_u	*p;
      int		cc;
  
      if (!ireg_ic
  #ifdef FEAT_MBYTE
  	    || (!enc_utf8 && mb_char2len(c) > 1)
  #endif
  	    )
  	return vim_strchr(s, c);
  
      /* tolower() and toupper() can be slow, comparing twice should be a lot
       * faster (esp. when using MS Visual C++!).
       * For UTF-8 need to use folded case. */
  #ifdef FEAT_MBYTE
      if (enc_utf8 && c > 0x80)
  	cc = utf_fold(c);
      else
  #endif
  	 if (MB_ISUPPER(c))
  	cc = MB_TOLOWER(c);
      else if (MB_ISLOWER(c))
  	cc = MB_TOUPPER(c);
      else
  	return vim_strchr(s, c);
  
  #ifdef FEAT_MBYTE
      if (has_mbyte)
      {
  	for (p = s; *p != NUL; p += (*mb_ptr2len)(p))
  	{
  	    if (enc_utf8 && c > 0x80)
  	    {
  		if (utf_fold(utf_ptr2char(p)) == cc)
  		    return p;
  	    }
  	    else if (*p == c || *p == cc)
  		return p;
  	}
      }
      else
  #endif
  	/* Faster version for when there are no multi-byte characters. */
  	for (p = s; *p != NUL; ++p)
  	    if (*p == c || *p == cc)
  		return p;
  
      return NULL;
  }
  
  /***************************************************************
   *		      regsub stuff			       *
   ***************************************************************/
  
  /*
   * We should define ftpr as a pointer to a function returning a pointer to
   * a function returning a pointer to a function ...
   * This is impossible, so we declare a pointer to a function returning a
   * pointer to a function returning void. This should work for all compilers.
   */
  typedef void (*(*fptr_T)(int *, int))();
  
  static fptr_T do_upper(int *, int);
  static fptr_T do_Upper(int *, int);
  static fptr_T do_lower(int *, int);
  static fptr_T do_Lower(int *, int);
  
  static int vim_regsub_both(char_u *source, char_u *dest, int copy, int magic, int backslash);
  
      static fptr_T
  do_upper(int *d, int c)
  {
      *d = MB_TOUPPER(c);
  
      return (fptr_T)NULL;
  }
  
      static fptr_T
  do_Upper(int *d, int c)
  {
      *d = MB_TOUPPER(c);
  
      return (fptr_T)do_Upper;
  }
  
      static fptr_T
  do_lower(int *d, int c)
  {
      *d = MB_TOLOWER(c);
  
      return (fptr_T)NULL;
  }
  
      static fptr_T
  do_Lower(int *d, int c)
  {
      *d = MB_TOLOWER(c);
  
      return (fptr_T)do_Lower;
  }
  
  /*
   * regtilde(): Replace tildes in the pattern by the old pattern.
   *
   * Short explanation of the tilde: It stands for the previous replacement
   * pattern.  If that previous pattern also contains a ~ we should go back a
   * step further...  But we insert the previous pattern into the current one
   * and remember that.
   * This still does not handle the case where "magic" changes.  So require the
   * user to keep his hands off of "magic".
   *
   * The tildes are parsed once before the first call to vim_regsub().
   */
      char_u *
  regtilde(char_u *source, int magic)
  {
      char_u	*newsub = source;
      char_u	*tmpsub;
      char_u	*p;
      int		len;
      int		prevlen;
  
      for (p = newsub; *p; ++p)
      {
  	if ((*p == '~' && magic) || (*p == '\\' && *(p + 1) == '~' && !magic))
  	{
  	    if (reg_prev_sub != NULL)
  	    {
  		/* length = len(newsub) - 1 + len(prev_sub) + 1 */
  		prevlen = (int)STRLEN(reg_prev_sub);
  		tmpsub = alloc((unsigned)(STRLEN(newsub) + prevlen));
  		if (tmpsub != NULL)
  		{
  		    /* copy prefix */
  		    len = (int)(p - newsub);	/* not including ~ */
  		    mch_memmove(tmpsub, newsub, (size_t)len);
  		    /* interpret tilde */
  		    mch_memmove(tmpsub + len, reg_prev_sub, (size_t)prevlen);
  		    /* copy postfix */
  		    if (!magic)
  			++p;			/* back off \ */
  		    STRCPY(tmpsub + len + prevlen, p + 1);
  
  		    if (newsub != source)	/* already allocated newsub */
  			vim_free(newsub);
  		    newsub = tmpsub;
  		    p = newsub + len + prevlen;
  		}
  	    }
  	    else if (magic)
  		STRMOVE(p, p + 1);	/* remove '~' */
  	    else
  		STRMOVE(p, p + 2);	/* remove '\~' */
  	    --p;
  	}
  	else
  	{
  	    if (*p == '\\' && p[1])		/* skip escaped characters */
  		++p;
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  		p += (*mb_ptr2len)(p) - 1;
  #endif
  	}
      }
  
      vim_free(reg_prev_sub);
      if (newsub != source)	/* newsub was allocated, just keep it */
  	reg_prev_sub = newsub;
      else			/* no ~ found, need to save newsub  */
  	reg_prev_sub = vim_strsave(newsub);
      return newsub;
  }
  
  #ifdef FEAT_EVAL
  static int can_f_submatch = FALSE;	/* TRUE when submatch() can be used */
  
  /* These pointers are used instead of reg_match and reg_mmatch for
   * reg_submatch().  Needed for when the substitution string is an expression
   * that contains a call to substitute() and submatch(). */
  static regmatch_T	*submatch_match;
  static regmmatch_T	*submatch_mmatch;
  static linenr_T		submatch_firstlnum;
  static linenr_T		submatch_maxline;
  static int		submatch_line_lbr;
  #endif
  
  #if defined(FEAT_MODIFY_FNAME) || defined(FEAT_EVAL) || defined(PROTO)
  /*
   * vim_regsub() - perform substitutions after a vim_regexec() or
   * vim_regexec_multi() match.
   *
   * If "copy" is TRUE really copy into "dest".
   * If "copy" is FALSE nothing is copied, this is just to find out the length
   * of the result.
   *
   * If "backslash" is TRUE, a backslash will be removed later, need to double
   * them to keep them, and insert a backslash before a CR to avoid it being
   * replaced with a line break later.
   *
   * Note: The matched text must not change between the call of
   * vim_regexec()/vim_regexec_multi() and vim_regsub()!  It would make the back
   * references invalid!
   *
   * Returns the size of the replacement, including terminating NUL.
   */
      int
  vim_regsub(
      regmatch_T	*rmp,
      char_u	*source,
      char_u	*dest,
      int		copy,
      int		magic,
      int		backslash)
  {
      reg_match = rmp;
      reg_mmatch = NULL;
      reg_maxline = 0;
      reg_buf = curbuf;
      reg_line_lbr = TRUE;
      return vim_regsub_both(source, dest, copy, magic, backslash);
  }
  #endif
  
      int
  vim_regsub_multi(
      regmmatch_T	*rmp,
      linenr_T	lnum,
      char_u	*source,
      char_u	*dest,
      int		copy,
      int		magic,
      int		backslash)
  {
      reg_match = NULL;
      reg_mmatch = rmp;
      reg_buf = curbuf;		/* always works on the current buffer! */
      reg_firstlnum = lnum;
      reg_maxline = curbuf->b_ml.ml_line_count - lnum;
      reg_line_lbr = FALSE;
      return vim_regsub_both(source, dest, copy, magic, backslash);
  }
  
      static int
  vim_regsub_both(
      char_u	*source,
      char_u	*dest,
      int		copy,
      int		magic,
      int		backslash)
  {
      char_u	*src;
      char_u	*dst;
      char_u	*s;
      int		c;
      int		cc;
      int		no = -1;
      fptr_T	func_all = (fptr_T)NULL;
      fptr_T	func_one = (fptr_T)NULL;
      linenr_T	clnum = 0;	/* init for GCC */
      int		len = 0;	/* init for GCC */
  #ifdef FEAT_EVAL
      static char_u *eval_result = NULL;
  #endif
  
      /* Be paranoid... */
      if (source == NULL || dest == NULL)
      {
  	EMSG(_(e_null));
  	return 0;
      }
      if (prog_magic_wrong())
  	return 0;
      src = source;
      dst = dest;
  
      /*
       * When the substitute part starts with "\=" evaluate it as an expression.
       */
      if (source[0] == '\\' && source[1] == '='
  #ifdef FEAT_EVAL
  	    && !can_f_submatch	    /* can't do this recursively */
  #endif
  	    )
      {
  #ifdef FEAT_EVAL
  	/* To make sure that the length doesn't change between checking the
  	 * length and copying the string, and to speed up things, the
  	 * resulting string is saved from the call with "copy" == FALSE to the
  	 * call with "copy" == TRUE. */
  	if (copy)
  	{
  	    if (eval_result != NULL)
  	    {
  		STRCPY(dest, eval_result);
  		dst += STRLEN(eval_result);
  		vim_free(eval_result);
  		eval_result = NULL;
  	    }
  	}
  	else
  	{
  	    win_T	*save_reg_win;
  	    int		save_ireg_ic;
  
  	    vim_free(eval_result);
  
  	    /* The expression may contain substitute(), which calls us
  	     * recursively.  Make sure submatch() gets the text from the first
  	     * level.  Don't need to save "reg_buf", because
  	     * vim_regexec_multi() can't be called recursively. */
  	    submatch_match = reg_match;
  	    submatch_mmatch = reg_mmatch;
  	    submatch_firstlnum = reg_firstlnum;
  	    submatch_maxline = reg_maxline;
  	    submatch_line_lbr = reg_line_lbr;
  	    save_reg_win = reg_win;
  	    save_ireg_ic = ireg_ic;
  	    can_f_submatch = TRUE;
  
  	    eval_result = eval_to_string(source + 2, NULL, TRUE);
  	    if (eval_result != NULL)
  	    {
  		int had_backslash = FALSE;
  
  		for (s = eval_result; *s != NUL; mb_ptr_adv(s))
  		{
  		    /* Change NL to CR, so that it becomes a line break,
  		     * unless called from vim_regexec_nl().
  		     * Skip over a backslashed character. */
  		    if (*s == NL && !submatch_line_lbr)
  			*s = CAR;
  		    else if (*s == '\\' && s[1] != NUL)
  		    {
  			++s;
  			/* Change NL to CR here too, so that this works:
  			 * :s/abc\\\ndef/\="aaa\\\nbbb"/  on text:
  			 *   abc\
  			 *   def
  			 * Not when called from vim_regexec_nl().
  			 */
  			if (*s == NL && !submatch_line_lbr)
  			    *s = CAR;
  			had_backslash = TRUE;
  		    }
  		}
  		if (had_backslash && backslash)
  		{
  		    /* Backslashes will be consumed, need to double them. */
  		    s = vim_strsave_escaped(eval_result, (char_u *)"\\");
  		    if (s != NULL)
  		    {
  			vim_free(eval_result);
  			eval_result = s;
  		    }
  		}
  
  		dst += STRLEN(eval_result);
  	    }
  
  	    reg_match = submatch_match;
  	    reg_mmatch = submatch_mmatch;
  	    reg_firstlnum = submatch_firstlnum;
  	    reg_maxline = submatch_maxline;
  	    reg_line_lbr = submatch_line_lbr;
  	    reg_win = save_reg_win;
  	    ireg_ic = save_ireg_ic;
  	    can_f_submatch = FALSE;
  	}
  #endif
      }
      else
        while ((c = *src++) != NUL)
        {
  	if (c == '&' && magic)
  	    no = 0;
  	else if (c == '\\' && *src != NUL)
  	{
  	    if (*src == '&' && !magic)
  	    {
  		++src;
  		no = 0;
  	    }
  	    else if ('0' <= *src && *src <= '9')
  	    {
  		no = *src++ - '0';
  	    }
  	    else if (vim_strchr((char_u *)"uUlLeE", *src))
  	    {
  		switch (*src++)
  		{
  		case 'u':   func_one = (fptr_T)do_upper;
  			    continue;
  		case 'U':   func_all = (fptr_T)do_Upper;
  			    continue;
  		case 'l':   func_one = (fptr_T)do_lower;
  			    continue;
  		case 'L':   func_all = (fptr_T)do_Lower;
  			    continue;
  		case 'e':
  		case 'E':   func_one = func_all = (fptr_T)NULL;
  			    continue;
  		}
  	    }
  	}
  	if (no < 0)	      /* Ordinary character. */
  	{
  	    if (c == K_SPECIAL && src[0] != NUL && src[1] != NUL)
  	    {
  		/* Copy a special key as-is. */
  		if (copy)
  		{
  		    *dst++ = c;
  		    *dst++ = *src++;
  		    *dst++ = *src++;
  		}
  		else
  		{
  		    dst += 3;
  		    src += 2;
  		}
  		continue;
  	    }
  
  	    if (c == '\\' && *src != NUL)
  	    {
  		/* Check for abbreviations -- webb */
  		switch (*src)
  		{
  		    case 'r':	c = CAR;	++src;	break;
  		    case 'n':	c = NL;		++src;	break;
  		    case 't':	c = TAB;	++src;	break;
  		 /* Oh no!  \e already has meaning in subst pat :-( */
  		 /* case 'e':   c = ESC;	++src;	break; */
  		    case 'b':	c = Ctrl_H;	++src;	break;
  
  		    /* If "backslash" is TRUE the backslash will be removed
  		     * later.  Used to insert a literal CR. */
  		    default:	if (backslash)
  				{
  				    if (copy)
  					*dst = '\\';
  				    ++dst;
  				}
  				c = *src++;
  		}
  	    }
  #ifdef FEAT_MBYTE
  	    else if (has_mbyte)
  		c = mb_ptr2char(src - 1);
  #endif
  
  	    /* Write to buffer, if copy is set. */
  	    if (func_one != (fptr_T)NULL)
  		/* Turbo C complains without the typecast */
  		func_one = (fptr_T)(func_one(&cc, c));
  	    else if (func_all != (fptr_T)NULL)
  		/* Turbo C complains without the typecast */
  		func_all = (fptr_T)(func_all(&cc, c));
  	    else /* just copy */
  		cc = c;
  
  #ifdef FEAT_MBYTE
  	    if (has_mbyte)
  	    {
  		int totlen = mb_ptr2len(src - 1);
  
  		if (copy)
  		    mb_char2bytes(cc, dst);
  		dst += mb_char2len(cc) - 1;
  		if (enc_utf8)
  		{
  		    int clen = utf_ptr2len(src - 1);
  
  		    /* If the character length is shorter than "totlen", there
  		     * are composing characters; copy them as-is. */
  		    if (clen < totlen)
  		    {
  			if (copy)
  			    mch_memmove(dst + 1, src - 1 + clen,
  						     (size_t)(totlen - clen));
  			dst += totlen - clen;
  		    }
  		}
  		src += totlen - 1;
  	    }
  	    else
  #endif
  		if (copy)
  		    *dst = cc;
  	    dst++;
  	}
  	else
  	{
  	    if (REG_MULTI)
  	    {
  		clnum = reg_mmatch->startpos[no].lnum;
  		if (clnum < 0 || reg_mmatch->endpos[no].lnum < 0)
  		    s = NULL;
  		else
  		{
  		    s = reg_getline(clnum) + reg_mmatch->startpos[no].col;
  		    if (reg_mmatch->endpos[no].lnum == clnum)
  			len = reg_mmatch->endpos[no].col
  					       - reg_mmatch->startpos[no].col;
  		    else
  			len = (int)STRLEN(s);
  		}
  	    }
  	    else
  	    {
  		s = reg_match->startp[no];
  		if (reg_match->endp[no] == NULL)
  		    s = NULL;
  		else
  		    len = (int)(reg_match->endp[no] - s);
  	    }
  	    if (s != NULL)
  	    {
  		for (;;)
  		{
  		    if (len == 0)
  		    {
  			if (REG_MULTI)
  			{
  			    if (reg_mmatch->endpos[no].lnum == clnum)
  				break;
  			    if (copy)
  				*dst = CAR;
  			    ++dst;
  			    s = reg_getline(++clnum);
  			    if (reg_mmatch->endpos[no].lnum == clnum)
  				len = reg_mmatch->endpos[no].col;
  			    else
  				len = (int)STRLEN(s);
  			}
  			else
  			    break;
  		    }
  		    else if (*s == NUL) /* we hit NUL. */
  		    {
  			if (copy)
  			    EMSG(_(e_re_damg));
  			goto exit;
  		    }
  		    else
  		    {
  			if (backslash && (*s == CAR || *s == '\\'))
  			{
  			    /*
  			     * Insert a backslash in front of a CR, otherwise
  			     * it will be replaced by a line break.
  			     * Number of backslashes will be halved later,
  			     * double them here.
  			     */
  			    if (copy)
  			    {
  				dst[0] = '\\';
  				dst[1] = *s;
  			    }
  			    dst += 2;
  			}
  			else
  			{
  #ifdef FEAT_MBYTE
  			    if (has_mbyte)
  				c = mb_ptr2char(s);
  			    else
  #endif
  				c = *s;
  
  			    if (func_one != (fptr_T)NULL)
  				/* Turbo C complains without the typecast */
  				func_one = (fptr_T)(func_one(&cc, c));
  			    else if (func_all != (fptr_T)NULL)
  				/* Turbo C complains without the typecast */
  				func_all = (fptr_T)(func_all(&cc, c));
  			    else /* just copy */
  				cc = c;
  
  #ifdef FEAT_MBYTE
  			    if (has_mbyte)
  			    {
  				int l;
  
  				/* Copy composing characters separately, one
  				 * at a time. */
  				if (enc_utf8)
  				    l = utf_ptr2len(s) - 1;
  				else
  				    l = mb_ptr2len(s) - 1;
  
  				s += l;
  				len -= l;
  				if (copy)
  				    mb_char2bytes(cc, dst);
  				dst += mb_char2len(cc) - 1;
  			    }
  			    else
  #endif
  				if (copy)
  				    *dst = cc;
  			    dst++;
  			}
  
  			++s;
  			--len;
  		    }
  		}
  	    }
  	    no = -1;
  	}
        }
      if (copy)
  	*dst = NUL;
  
  exit:
      return (int)((dst - dest) + 1);
  }
  
  #ifdef FEAT_EVAL
  static char_u *reg_getline_submatch(linenr_T lnum);
  
  /*
   * Call reg_getline() with the line numbers from the submatch.  If a
   * substitute() was used the reg_maxline and other values have been
   * overwritten.
   */
      static char_u *
  reg_getline_submatch(linenr_T lnum)
  {
      char_u *s;
      linenr_T save_first = reg_firstlnum;
      linenr_T save_max = reg_maxline;
  
      reg_firstlnum = submatch_firstlnum;
      reg_maxline = submatch_maxline;
  
      s = reg_getline(lnum);
  
      reg_firstlnum = save_first;
      reg_maxline = save_max;
      return s;
  }
  
  /*
   * Used for the submatch() function: get the string from the n'th submatch in
   * allocated memory.
   * Returns NULL when not in a ":s" command and for a non-existing submatch.
   */
      char_u *
  reg_submatch(int no)
  {
      char_u	*retval = NULL;
      char_u	*s;
      int		len;
      int		round;
      linenr_T	lnum;
  
      if (!can_f_submatch || no < 0)
  	return NULL;
  
      if (submatch_match == NULL)
      {
  	/*
  	 * First round: compute the length and allocate memory.
  	 * Second round: copy the text.
  	 */
  	for (round = 1; round <= 2; ++round)
  	{
  	    lnum = submatch_mmatch->startpos[no].lnum;
  	    if (lnum < 0 || submatch_mmatch->endpos[no].lnum < 0)
  		return NULL;
  
  	    s = reg_getline_submatch(lnum) + submatch_mmatch->startpos[no].col;
  	    if (s == NULL)  /* anti-crash check, cannot happen? */
  		break;
  	    if (submatch_mmatch->endpos[no].lnum == lnum)
  	    {
  		/* Within one line: take form start to end col. */
  		len = submatch_mmatch->endpos[no].col
  					  - submatch_mmatch->startpos[no].col;
  		if (round == 2)
  		    vim_strncpy(retval, s, len);
  		++len;
  	    }
  	    else
  	    {
  		/* Multiple lines: take start line from start col, middle
  		 * lines completely and end line up to end col. */
  		len = (int)STRLEN(s);
  		if (round == 2)
  		{
  		    STRCPY(retval, s);
  		    retval[len] = '\n';
  		}
  		++len;
  		++lnum;
  		while (lnum < submatch_mmatch->endpos[no].lnum)
  		{
  		    s = reg_getline_submatch(lnum++);
  		    if (round == 2)
  			STRCPY(retval + len, s);
  		    len += (int)STRLEN(s);
  		    if (round == 2)
  			retval[len] = '\n';
  		    ++len;
  		}
  		if (round == 2)
  		    STRNCPY(retval + len, reg_getline_submatch(lnum),
  					     submatch_mmatch->endpos[no].col);
  		len += submatch_mmatch->endpos[no].col;
  		if (round == 2)
  		    retval[len] = NUL;
  		++len;
  	    }
  
  	    if (retval == NULL)
  	    {
  		retval = lalloc((long_u)len, TRUE);
  		if (retval == NULL)
  		    return NULL;
  	    }
  	}
      }
      else
      {
  	s = submatch_match->startp[no];
  	if (s == NULL || submatch_match->endp[no] == NULL)
  	    retval = NULL;
  	else
  	    retval = vim_strnsave(s, (int)(submatch_match->endp[no] - s));
      }
  
      return retval;
  }
  
  /*
   * Used for the submatch() function with the optional non-zero argument: get
   * the list of strings from the n'th submatch in allocated memory with NULs
   * represented in NLs.
   * Returns a list of allocated strings.  Returns NULL when not in a ":s"
   * command, for a non-existing submatch and for any error.
   */
      list_T *
  reg_submatch_list(int no)
  {
      char_u	*s;
      linenr_T	slnum;
      linenr_T	elnum;
      colnr_T	scol;
      colnr_T	ecol;
      int		i;
      list_T	*list;
      int		error = FALSE;
  
      if (!can_f_submatch || no < 0)
  	return NULL;
  
      if (submatch_match == NULL)
      {
  	slnum = submatch_mmatch->startpos[no].lnum;
  	elnum = submatch_mmatch->endpos[no].lnum;
  	if (slnum < 0 || elnum < 0)
  	    return NULL;
  
  	scol = submatch_mmatch->startpos[no].col;
  	ecol = submatch_mmatch->endpos[no].col;
  
  	list = list_alloc();
  	if (list == NULL)
  	    return NULL;
  
  	s = reg_getline_submatch(slnum) + scol;
  	if (slnum == elnum)
  	{
  	    if (list_append_string(list, s, ecol - scol) == FAIL)
  		error = TRUE;
  	}
  	else
  	{
  	    if (list_append_string(list, s, -1) == FAIL)
  		error = TRUE;
  	    for (i = 1; i < elnum - slnum; i++)
  	    {
  		s = reg_getline_submatch(slnum + i);
  		if (list_append_string(list, s, -1) == FAIL)
  		    error = TRUE;
  	    }
  	    s = reg_getline_submatch(elnum);
  	    if (list_append_string(list, s, ecol) == FAIL)
  		error = TRUE;
  	}
      }
      else
      {
  	s = submatch_match->startp[no];
  	if (s == NULL || submatch_match->endp[no] == NULL)
  	    return NULL;
  	list = list_alloc();
  	if (list == NULL)
  	    return NULL;
  	if (list_append_string(list, s,
  				 (int)(submatch_match->endp[no] - s)) == FAIL)
  	    error = TRUE;
      }
  
      if (error)
      {
  	list_free(list, TRUE);
  	return NULL;
      }
      return list;
  }
  #endif
  
  static regengine_T bt_regengine =
  {
      bt_regcomp,
      bt_regfree,
      bt_regexec_nl,
      bt_regexec_multi,
      (char_u *)""
  };
  
  #include "regexp_nfa.c"
  
  static regengine_T nfa_regengine =
  {
      nfa_regcomp,
      nfa_regfree,
      nfa_regexec_nl,
      nfa_regexec_multi,
      (char_u *)""
  };
  
  /* Which regexp engine to use? Needed for vim_regcomp().
   * Must match with 'regexpengine'. */
  static int regexp_engine = 0;
  
  #ifdef DEBUG
  static char_u regname[][30] = {
  		    "AUTOMATIC Regexp Engine",
  		    "BACKTRACKING Regexp Engine",
  		    "NFA Regexp Engine"
  			    };
  #endif
  
  /*
   * Compile a regular expression into internal code.
   * Returns the program in allocated memory.
   * Use vim_regfree() to free the memory.
   * Returns NULL for an error.
   */
      regprog_T *
  vim_regcomp(char_u *expr_arg, int re_flags)
  {
      regprog_T   *prog = NULL;
      char_u	*expr = expr_arg;
  
      regexp_engine = p_re;
  
      /* Check for prefix "\%#=", that sets the regexp engine */
      if (STRNCMP(expr, "\\%#=", 4) == 0)
      {
  	int newengine = expr[4] - '0';
  
  	if (newengine == AUTOMATIC_ENGINE
  	    || newengine == BACKTRACKING_ENGINE
  	    || newengine == NFA_ENGINE)
  	{
  	    regexp_engine = expr[4] - '0';
  	    expr += 5;
  #ifdef DEBUG
  	    smsg((char_u *)"New regexp mode selected (%d): %s",
  					   regexp_engine, regname[newengine]);
  #endif
  	}
  	else
  	{
  	    EMSG(_("E864: \\%#= can only be followed by 0, 1, or 2. The automatic engine will be used "));
  	    regexp_engine = AUTOMATIC_ENGINE;
  	}
      }
      bt_regengine.expr = expr;
      nfa_regengine.expr = expr;
  
      /*
       * First try the NFA engine, unless backtracking was requested.
       */
      if (regexp_engine != BACKTRACKING_ENGINE)
          prog = nfa_regengine.regcomp(expr,
  		re_flags + (regexp_engine == AUTOMATIC_ENGINE ? RE_AUTO : 0));
      else
  	prog = bt_regengine.regcomp(expr, re_flags);
  
      /* Check for error compiling regexp with initial engine. */
      if (prog == NULL)
      {
  #ifdef BT_REGEXP_DEBUG_LOG
  	if (regexp_engine != BACKTRACKING_ENGINE)   /* debugging log for NFA */
  	{
  	    FILE *f;
  	    f = fopen(BT_REGEXP_DEBUG_LOG_NAME, "a");
  	    if (f)
  	    {
  		fprintf(f, "Syntax error in \"%s\"\n", expr);
  		fclose(f);
  	    }
  	    else
  		EMSG2("(NFA) Could not open \"%s\" to write !!!",
                          BT_REGEXP_DEBUG_LOG_NAME);
  	}
  #endif
  	/*
  	 * If the NFA engine failed, try the backtracking engine.
  	 * The NFA engine also fails for patterns that it can't handle well
  	 * but are still valid patterns, thus a retry should work.
  	 */
  	if (regexp_engine == AUTOMATIC_ENGINE)
  	{
  	    regexp_engine = BACKTRACKING_ENGINE;
  	    prog = bt_regengine.regcomp(expr, re_flags);
  	}
      }
  
      if (prog != NULL)
      {
  	/* Store the info needed to call regcomp() again when the engine turns
  	 * out to be very slow when executing it. */
  	prog->re_engine = regexp_engine;
  	prog->re_flags  = re_flags;
      }
  
      return prog;
  }
  
  /*
   * Free a compiled regexp program, returned by vim_regcomp().
   */
      void
  vim_regfree(regprog_T *prog)
  {
      if (prog != NULL)
  	prog->engine->regfree(prog);
  }
  
  #ifdef FEAT_EVAL
  static void report_re_switch(char_u *pat);
  
      static void
  report_re_switch(char_u *pat)
  {
      if (p_verbose > 0)
      {
  	verbose_enter();
  	MSG_PUTS(_("Switching to backtracking RE engine for pattern: "));
  	MSG_PUTS(pat);
  	verbose_leave();
      }
  }
  #endif
  
  static int vim_regexec_both(regmatch_T *rmp, char_u *line, colnr_T col, int nl);
  
  /*
   * Match a regexp against a string.
   * "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
   * Note: "rmp->regprog" may be freed and changed.
   * Uses curbuf for line count and 'iskeyword'.
   * When "nl" is TRUE consider a "\n" in "line" to be a line break.
   *
   * Return TRUE if there is a match, FALSE if not.
   */
      static int
  vim_regexec_both(
      regmatch_T	*rmp,
      char_u	*line,  /* string to match against */
      colnr_T	col,    /* column to start looking for match */
      int		nl)
  {
      int result = rmp->regprog->engine->regexec_nl(rmp, line, col, nl);
  
      /* NFA engine aborted because it's very slow. */
      if (rmp->regprog->re_engine == AUTOMATIC_ENGINE
  					       && result == NFA_TOO_EXPENSIVE)
      {
  	int    save_p_re = p_re;
  	int    re_flags = rmp->regprog->re_flags;
  	char_u *pat = vim_strsave(((nfa_regprog_T *)rmp->regprog)->pattern);
  
  	p_re = BACKTRACKING_ENGINE;
  	vim_regfree(rmp->regprog);
  	if (pat != NULL)
  	{
  #ifdef FEAT_EVAL
  	    report_re_switch(pat);
  #endif
  	    rmp->regprog = vim_regcomp(pat, re_flags);
  	    if (rmp->regprog != NULL)
  		result = rmp->regprog->engine->regexec_nl(rmp, line, col, nl);
  	    vim_free(pat);
  	}
  
  	p_re = save_p_re;
      }
      return result > 0;
  }
  
  /*
   * Note: "*prog" may be freed and changed.
   * Return TRUE if there is a match, FALSE if not.
   */
      int
  vim_regexec_prog(
      regprog_T	**prog,
      int		ignore_case,
      char_u	*line,
      colnr_T	col)
  {
      int r;
      regmatch_T regmatch;
  
      regmatch.regprog = *prog;
      regmatch.rm_ic = ignore_case;
      r = vim_regexec_both(&regmatch, line, col, FALSE);
      *prog = regmatch.regprog;
      return r;
  }
  
  /*
   * Note: "rmp->regprog" may be freed and changed.
   * Return TRUE if there is a match, FALSE if not.
   */
      int
  vim_regexec(regmatch_T *rmp, char_u *line, colnr_T col)
  {
      return vim_regexec_both(rmp, line, col, FALSE);
  }
  
  #if defined(FEAT_MODIFY_FNAME) || defined(FEAT_EVAL) \
  	|| defined(FIND_REPLACE_DIALOG) || defined(PROTO)
  /*
   * Like vim_regexec(), but consider a "\n" in "line" to be a line break.
   * Note: "rmp->regprog" may be freed and changed.
   * Return TRUE if there is a match, FALSE if not.
   */
      int
  vim_regexec_nl(regmatch_T *rmp, char_u *line, colnr_T col)
  {
      return vim_regexec_both(rmp, line, col, TRUE);
  }
  #endif
  
  /*
   * Match a regexp against multiple lines.
   * "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
   * Note: "rmp->regprog" may be freed and changed.
   * Uses curbuf for line count and 'iskeyword'.
   *
   * Return zero if there is no match.  Return number of lines contained in the
   * match otherwise.
   */
      long
  vim_regexec_multi(
      regmmatch_T *rmp,
      win_T       *win,           /* window in which to search or NULL */
      buf_T       *buf,           /* buffer in which to search */
      linenr_T    lnum,           /* nr of line to start looking for match */
      colnr_T     col,            /* column to start looking for match */
      proftime_T	*tm)		/* timeout limit or NULL */
  {
      int result = rmp->regprog->engine->regexec_multi(
  						rmp, win, buf, lnum, col, tm);
  
      /* NFA engine aborted because it's very slow. */
      if (rmp->regprog->re_engine == AUTOMATIC_ENGINE
  					       && result == NFA_TOO_EXPENSIVE)
      {
  	int    save_p_re = p_re;
  	int    re_flags = rmp->regprog->re_flags;
  	char_u *pat = vim_strsave(((nfa_regprog_T *)rmp->regprog)->pattern);
  
  	p_re = BACKTRACKING_ENGINE;
  	vim_regfree(rmp->regprog);
  	if (pat != NULL)
  	{
  #ifdef FEAT_EVAL
  	    report_re_switch(pat);
  #endif
  	    rmp->regprog = vim_regcomp(pat, re_flags);
  	    if (rmp->regprog != NULL)
  		result = rmp->regprog->engine->regexec_multi(
  						rmp, win, buf, lnum, col, tm);
  	    vim_free(pat);
  	}
  	p_re = save_p_re;
      }
  
      return result <= 0 ? 0 : result;
  }
  