text: /*
   * Copyright (C) 1984-2015  Mark Nudelman
   *
   * You may distribute under the terms of either the GNU General Public
   * License or the Less License, as specified in the README file.
   *
   * For more information, see the README file.
   */
  
  
  /*
   * The option table.
   */
  
  #include "less.h"
  #include "option.h"
  
  /*
   * Variables controlled by command line options.
   */
  public int quiet;		/* Should we suppress the audible bell? */
  public int how_search;		/* Where should forward searches start? */
  public int top_scroll;		/* Repaint screen from top?
  				   (alternative is scroll from bottom) */
  public int pr_type;		/* Type of prompt (short, medium, long) */
  public int bs_mode;		/* How to process backspaces */
  public int know_dumb;		/* Don't complain about dumb terminals */
  public int quit_at_eof;		/* Quit after hitting end of file twice */
  public int quit_if_one_screen;	/* Quit if EOF on first screen */
  public int squeeze;		/* Squeeze multiple blank lines into one */
  public int tabstop;		/* Tab settings */
  public int back_scroll;		/* Repaint screen on backwards movement */
  public int forw_scroll;		/* Repaint screen on forward movement */
  public int caseless;		/* Do "caseless" searches */
  public int linenums;		/* Use line numbers */
  public int autobuf;		/* Automatically allocate buffers as needed */
  public int bufspace;		/* Max buffer space per file (K) */
  public int ctldisp;		/* Send control chars to screen untranslated */
  public int force_open;		/* Open the file even if not regular file */
  public int swindow;		/* Size of scrolling window */
  public int jump_sline;		/* Screen line of "jump target" */
  public int jump_sline_fraction = -1;
  public int shift_count_fraction = -1;
  public int chopline;		/* Truncate displayed lines at screen width */
  public int no_init;		/* Disable sending ti/te termcap strings */
  public int no_keypad;		/* Disable sending ks/ke termcap strings */
  public int twiddle;             /* Show tildes after EOF */
  public int show_attn;		/* Hilite first unread line */
  public int shift_count;		/* Number of positions to shift horizontally */
  public int status_col;		/* Display a status column */
  public int use_lessopen;	/* Use the LESSOPEN filter */
  public int quit_on_intr;	/* Quit on interrupt */
  public int follow_mode;		/* F cmd Follows file desc or file name? */
  public int oldbot;		/* Old bottom of screen behavior {{REMOVE}} */
  public int opt_use_backslash;	/* Use backslash escaping in option parsing */
  #if HILITE_SEARCH
  public int hilite_search;	/* Highlight matched search patterns? */
  #endif
  
  public int less_is_more = 0;	/* Make compatible with POSIX more */
  
  /*
   * Long option names.
   */
  static struct optname a_optname      = { "search-skip-screen",   NULL };
  static struct optname b_optname      = { "buffers",              NULL };
  static struct optname B__optname     = { "auto-buffers",         NULL };
  static struct optname c_optname      = { "clear-screen",         NULL };
  static struct optname d_optname      = { "dumb",                 NULL };
  #if MSDOS_COMPILER
  static struct optname D__optname     = { "color",                NULL };
  #endif
  static struct optname e_optname      = { "quit-at-eof",          NULL };
  static struct optname f_optname      = { "force",                NULL };
  static struct optname F__optname     = { "quit-if-one-screen",   NULL };
  #if HILITE_SEARCH
  static struct optname g_optname      = { "hilite-search",        NULL };
  #endif
  static struct optname h_optname      = { "max-back-scroll",      NULL };
  static struct optname i_optname      = { "ignore-case",          NULL };
  static struct optname j_optname      = { "jump-target",          NULL };
  static struct optname J__optname     = { "status-column",        NULL };
  #if USERFILE
  static struct optname k_optname      = { "lesskey-file",         NULL };
  #endif
  static struct optname K__optname     = { "quit-on-intr",         NULL };
  static struct optname L__optname     = { "no-lessopen",          NULL };
  static struct optname m_optname      = { "long-prompt",          NULL };
  static struct optname n_optname      = { "line-numbers",         NULL };
  #if LOGFILE
  static struct optname o_optname      = { "log-file",             NULL };
  static struct optname O__optname     = { "LOG-FILE",             NULL };
  #endif
  static struct optname p_optname      = { "pattern",              NULL };
  static struct optname P__optname     = { "prompt",               NULL };
  static struct optname q2_optname     = { "silent",               NULL };
  static struct optname q_optname      = { "quiet",                &q2_optname };
  static struct optname r_optname      = { "raw-control-chars",    NULL };
  static struct optname s_optname      = { "squeeze-blank-lines",  NULL };
  static struct optname S__optname     = { "chop-long-lines",      NULL };
  #if TAGS
  static struct optname t_optname      = { "tag",                  NULL };
  static struct optname T__optname     = { "tag-file",             NULL };
  #endif
  static struct optname u_optname      = { "underline-special",    NULL };
  static struct optname V__optname     = { "version",              NULL };
  static struct optname w_optname      = { "hilite-unread",        NULL };
  static struct optname x_optname      = { "tabs",                 NULL };
  static struct optname X__optname     = { "no-init",              NULL };
  static struct optname y_optname      = { "max-forw-scroll",      NULL };
  static struct optname z_optname      = { "window",               NULL };
  static struct optname quote_optname  = { "quotes",               NULL };
  static struct optname tilde_optname  = { "tilde",                NULL };
  static struct optname query_optname  = { "help",                 NULL };
  static struct optname pound_optname  = { "shift",                NULL };
  static struct optname keypad_optname = { "no-keypad",            NULL };
  static struct optname oldbot_optname = { "old-bot",              NULL };
  static struct optname follow_optname = { "follow-name",          NULL };
  static struct optname use_backslash_optname = { "use-backslash", NULL };
  
  
  /*
   * Table of all options and their semantics.
   *
   * For BOOL and TRIPLE options, odesc[0], odesc[1], odesc[2] are
   * the description of the option when set to 0, 1 or 2, respectively.
   * For NUMBER options, odesc[0] is the prompt to use when entering
   * a new value, and odesc[1] is the description, which should contain 
   * one %d which is replaced by the value of the number.
   * For STRING options, odesc[0] is the prompt to use when entering
   * a new value, and odesc[1], if not NULL, is the set of characters
   * that are valid in the string.
   */
  static struct loption option[] =
  {
  	{ 'a', &a_optname,
  		TRIPLE, OPT_ONPLUS, &how_search, NULL,
  		{
  			"Search includes displayed screen",
  			"Search skips displayed screen",
  			"Search includes all of displayed screen"
  		}
  	},
  
  	{ 'b', &b_optname,
  		NUMBER|INIT_HANDLER, 64, &bufspace, opt_b, 
  		{
  			"Max buffer space per file (K): ",
  			"Max buffer space per file: %dK",
  			NULL
  		}
  	},
  	{ 'B', &B__optname,
  		BOOL, OPT_ON, &autobuf, NULL,
  		{
  			"Don't automatically allocate buffers",
  			"Automatically allocate buffers when needed",
  			NULL
  		}
  	},
  	{ 'c', &c_optname,
  		TRIPLE, OPT_OFF, &top_scroll, NULL,
  		{
  			"Repaint by scrolling from bottom of screen",
  			"Repaint by painting from top of screen",
  			"Repaint by painting from top of screen"
  		}
  	},
  	{ 'd', &d_optname,
  		BOOL|NO_TOGGLE, OPT_OFF, &know_dumb, NULL,
  		{
  			"Assume intelligent terminal",
  			"Assume dumb terminal",
  			NULL
  		}
  	},
  #if MSDOS_COMPILER
  	{ 'D', &D__optname,
  		STRING|REPAINT|NO_QUERY, 0, NULL, opt_D,
  		{
  			"color desc: ", 
  			"Ddknsu0123456789.",
  			NULL
  		}
  	},
  #endif
  	{ 'e', &e_optname,
  		TRIPLE, OPT_OFF, &quit_at_eof, NULL,
  		{
  			"Don't quit at end-of-file",
  			"Quit at end-of-file",
  			"Quit immediately at end-of-file"
  		}
  	},
  	{ 'f', &f_optname,
  		BOOL, OPT_OFF, &force_open, NULL,
  		{
  			"Open only regular files",
  			"Open even non-regular files",
  			NULL
  		}
  	},
  	{ 'F', &F__optname,
  		BOOL, OPT_OFF, &quit_if_one_screen, NULL,
  		{
  			"Don't quit if end-of-file on first screen",
  			"Quit if end-of-file on first screen",
  			NULL
  		}
  	},
  #if HILITE_SEARCH
  	{ 'g', &g_optname,
  		TRIPLE|HL_REPAINT, OPT_ONPLUS, &hilite_search, NULL,
  		{
  			"Don't highlight search matches",
  			"Highlight matches for previous search only",
  			"Highlight all matches for previous search pattern",
  		}
  	},
  #endif
  	{ 'h', &h_optname,
  		NUMBER, -1, &back_scroll, NULL,
  		{
  			"Backwards scroll limit: ",
  			"Backwards scroll limit is %d lines",
  			NULL
  		}
  	},
  	{ 'i', &i_optname,
  		TRIPLE|HL_REPAINT, OPT_OFF, &caseless, opt_i,
  		{
  			"Case is significant in searches",
  			"Ignore case in searches",
  			"Ignore case in searches and in patterns"
  		}
  	},
  	{ 'j', &j_optname,
  		STRING, 0, NULL, opt_j,
  		{
  			"Target line: ",
  			"0123456789.-",
  			NULL
  		}
  	},
  	{ 'J', &J__optname,
  		BOOL|REPAINT, OPT_OFF, &status_col, NULL,
  		{
  			"Don't display a status column",
  			"Display a status column",
  			NULL
  		}
  	},
  #if USERFILE
  	{ 'k', &k_optname,
  		STRING|NO_TOGGLE|NO_QUERY, 0, NULL, opt_k,
  		{ NULL, NULL, NULL }
  	},
  #endif
  	{ 'K', &K__optname,
  		BOOL, OPT_OFF, &quit_on_intr, NULL,
  		{
  			"Interrupt (ctrl-C) returns to prompt",
  			"Interrupt (ctrl-C) exits less",
  			NULL
  		}
  	},
  	{ 'L', &L__optname,
  		BOOL, OPT_ON, &use_lessopen, NULL,
  		{
  			"Don't use the LESSOPEN filter",
  			"Use the LESSOPEN filter",
  			NULL
  		}
  	},
  	{ 'm', &m_optname,
  		TRIPLE, OPT_OFF, &pr_type, NULL,
  		{
  			"Short prompt",
  			"Medium prompt",
  			"Long prompt"
  		}
  	},
  	{ 'n', &n_optname,
  		TRIPLE|REPAINT, OPT_ON, &linenums, NULL,
  		{
  			"Don't use line numbers",
  			"Use line numbers",
  			"Constantly display line numbers"
  		}
  	},
  #if LOGFILE
  	{ 'o', &o_optname,
  		STRING, 0, NULL, opt_o,
  		{ "log file: ", NULL, NULL }
  	},
  	{ 'O', &O__optname,
  		STRING, 0, NULL, opt__O,
  		{ "Log file: ", NULL, NULL }
  	},
  #endif
  	{ 'p', &p_optname,
  		STRING|NO_TOGGLE|NO_QUERY, 0, NULL, opt_p,
  		{ NULL, NULL, NULL }
  	},
  	{ 'P', &P__optname,
  		STRING, 0, NULL, opt__P,
  		{ "prompt: ", NULL, NULL }
  	},
  	{ 'q', &q_optname,
  		TRIPLE, OPT_OFF, &quiet, NULL,
  		{
  			"Ring the bell for errors AND at eof/bof",
  			"Ring the bell for errors but not at eof/bof",
  			"Never ring the bell"
  		}
  	},
  	{ 'r', &r_optname,
  		TRIPLE|REPAINT, OPT_OFF, &ctldisp, NULL,
  		{
  			"Display control characters as ^X",
  			"Display control characters directly",
  			"Display control characters directly, processing ANSI sequences"
  		}
  	},
  	{ 's', &s_optname,
  		BOOL|REPAINT, OPT_OFF, &squeeze, NULL,
  		{
  			"Display all blank lines",
  			"Squeeze multiple blank lines",
  			NULL
  		}
  	},
  	{ 'S', &S__optname,
  		BOOL|REPAINT, OPT_OFF, &chopline, NULL,
  		{
  			"Fold long lines",
  			"Chop long lines",
  			NULL
  		}
  	},
  #if TAGS
  	{ 't', &t_optname,
  		STRING|NO_QUERY, 0, NULL, opt_t,
  		{ "tag: ", NULL, NULL }
  	},
  	{ 'T', &T__optname,
  		STRING, 0, NULL, opt__T,
  		{ "tags file: ", NULL, NULL }
  	},
  #endif
  	{ 'u', &u_optname,
  		TRIPLE|REPAINT, OPT_OFF, &bs_mode, NULL,
  		{
  			"Display underlined text in underline mode",
  			"Backspaces cause overstrike",
  			"Print backspace as ^H"
  		}
  	},
  	{ 'V', &V__optname,
  		NOVAR, 0, NULL, opt__V,
  		{ NULL, NULL, NULL }
  	},
  	{ 'w', &w_optname,
  		TRIPLE|REPAINT, OPT_OFF, &show_attn, NULL,
  		{
  			"Don't highlight first unread line",
  			"Highlight first unread line after forward-screen",
  			"Highlight first unread line after any forward movement",
  		}
  	},
  	{ 'x', &x_optname,
  		STRING|REPAINT, 0, NULL, opt_x,
  		{
  			"Tab stops: ",
  			"0123456789,",
  			NULL
  		}
  	},
  	{ 'X', &X__optname,
  		BOOL|NO_TOGGLE, OPT_OFF, &no_init, NULL,
  		{
  			"Send init/deinit strings to terminal",
  			"Don't use init/deinit strings",
  			NULL
  		}
  	},
  	{ 'y', &y_optname,
  		NUMBER, -1, &forw_scroll, NULL,
  		{
  			"Forward scroll limit: ",
  			"Forward scroll limit is %d lines",
  			NULL
  		}
  	},
  	{ 'z', &z_optname,
  		NUMBER, -1, &swindow, NULL,
  		{
  			"Scroll window size: ",
  			"Scroll window size is %d lines",
  			NULL
  		}
  	},
  	{ '"', &quote_optname,
  		STRING, 0, NULL, opt_quote,
  		{ "quotes: ", NULL, NULL }
  	},
  	{ '~', &tilde_optname,
  		BOOL|REPAINT, OPT_ON, &twiddle, NULL,
  		{
  			"Don't show tildes after end of file",
  			"Show tildes after end of file",
  			NULL
  		}
  	},
  	{ '?', &query_optname,
  		NOVAR, 0, NULL, opt_query,
  		{ NULL, NULL, NULL }
  	},
  	{ '#', &pound_optname,
  		STRING, 0, NULL, opt_shift,
  		{
  			"Horizontal shift: ",
  			"0123456789.",
  			NULL
  		}
  	},
  	{ OLETTER_NONE, &keypad_optname,
  		BOOL|NO_TOGGLE, OPT_OFF, &no_keypad, NULL,
  		{
  			"Use keypad mode",
  			"Don't use keypad mode",
  			NULL
  		}
  	},
  	{ OLETTER_NONE, &oldbot_optname,
  		BOOL, OPT_OFF, &oldbot, NULL,
  		{
  			"Use new bottom of screen behavior",
  			"Use old bottom of screen behavior",
  			NULL
  		}
  	},
  	{ OLETTER_NONE, &follow_optname,
  		BOOL, FOLLOW_DESC, &follow_mode, NULL,
  		{
  			"F command follows file descriptor",
  			"F command follows file name",
  			NULL
  		}
  	},
  	{ OLETTER_NONE, &use_backslash_optname,
  		BOOL, OPT_OFF, &opt_use_backslash, NULL,
  		{
  			"Use backslash escaping in command line parameters",
  			"Don't use backslash escaping in command line parameters",
  			NULL
  		}
  	},
  	{ '\0', NULL, NOVAR, 0, NULL, NULL, { NULL, NULL, NULL } }
  };
  
  
  /*
   * Initialize each option to its default value.
   */
  	public void
  init_option()
  {
  	register struct loption *o;
  	char *p;
  
  	p = lgetenv("LESS_IS_MORE");
  	if (p != NULL && *p != '\0')
  		less_is_more = 1;
  
  	for (o = option;  o->oletter != '\0';  o++)
  	{
  		/*
  		 * Set each variable to its default.
  		 */
  		if (o->ovar != NULL)
  			*(o->ovar) = o->odefault;
  		if (o->otype & INIT_HANDLER)
  			(*(o->ofunc))(INIT, (char *) NULL);
  	}
  }
  
  /*
   * Find an option in the option table, given its option letter.
   */
  	public struct loption *
  findopt(c)
  	int c;
  {
  	register struct loption *o;
  
  	for (o = option;  o->oletter != '\0';  o++)
  	{
  		if (o->oletter == c)
  			return (o);
  		if ((o->otype & TRIPLE) && ASCII_TO_UPPER(o->oletter) == c)
  			return (o);
  	}
  	return (NULL);
  }
  
  /*
   *
   */
  	static int
  is_optchar(c)
  	char c;
  {
  	if (ASCII_IS_UPPER(c))
  		return 1;
  	if (ASCII_IS_LOWER(c))
  		return 1;
  	if (c == '-')
  		return 1;
  	return 0;
  }
  
  /*
   * Find an option in the option table, given its option name.
   * p_optname is the (possibly partial) name to look for, and
   * is updated to point after the matched name.
   * p_oname if non-NULL is set to point to the full option name.
   */
  	public struct loption *
  findopt_name(p_optname, p_oname, p_err)
  	char **p_optname;
  	char **p_oname;
  	int *p_err;
  {
  	char *optname = *p_optname;
  	register struct loption *o;
  	register struct optname *oname;
  	register int len;
  	int uppercase;
  	struct loption *maxo = NULL;
  	struct optname *maxoname = NULL;
  	int maxlen = 0;
  	int ambig = 0;
  	int exact = 0;
  
  	/*
  	 * Check all options.
  	 */
  	for (o = option;  o->oletter != '\0';  o++)
  	{
  		/*
  		 * Check all names for this option.
  		 */
  		for (oname = o->onames;  oname != NULL;  oname = oname->onext)
  		{
  			/* 
  			 * Try normal match first (uppercase == 0),
  			 * then, then if it's a TRIPLE option,
  			 * try uppercase match (uppercase == 1).
  			 */
  			for (uppercase = 0;  uppercase <= 1;  uppercase++)
  			{
  				len = sprefix(optname, oname->oname, uppercase);
  				if (len <= 0 || is_optchar(optname[len]))
  				{
  					/*
  					 * We didn't use all of the option name.
  					 */
  					continue;
  				}
  				if (!exact && len == maxlen)
  					/*
  					 * Already had a partial match,
  					 * and now there's another one that
  					 * matches the same length.
  					 */
  					ambig = 1;
  				else if (len > maxlen)
  				{
  					/*
  					 * Found a better match than
  					 * the one we had.
  					 */
  					maxo = o;
  					maxoname = oname;
  					maxlen = len;
  					ambig = 0;
  					exact = (len == (int)strlen(oname->oname));
  				}
  				if (!(o->otype & TRIPLE))
  					break;
  			}
  		}
  	}
  	if (ambig)
  	{
  		/*
  		 * Name matched more than one option.
  		 */
  		if (p_err != NULL)
  			*p_err = OPT_AMBIG;
  		return (NULL);
  	}
  	*p_optname = optname + maxlen;
  	if (p_oname != NULL)
  		*p_oname = maxoname == NULL ? NULL : maxoname->oname;
  	return (maxo);
  }
  