text: /**********************************************************************
  
    pack.c -
  
    $Author$
    created at: Thu Feb 10 15:17:05 JST 1994
  
    Copyright (C) 1993-2007 Yukihiro Matsumoto
  
  **********************************************************************/
  
  #include "internal.h"
  #include <sys/types.h>
  #include <ctype.h>
  #include <errno.h>
  
  /*
   * It is intentional that the condition for natstr is HAVE_TRUE_LONG_LONG
   * instead of HAVE_LONG_LONG or LONG_LONG.
   * This means q! and Q! means always the standard long long type and
   * causes ArgumentError for platforms which has no long long type,
   * even if the platform has an implementation specific 64bit type.
   * This behavior is consistent with the document of pack/unpack.
   */
  #ifdef HAVE_TRUE_LONG_LONG
  static const char natstr[] = "sSiIlLqQjJ";
  #else
  static const char natstr[] = "sSiIlLjJ";
  #endif
  static const char endstr[] = "sSiIlLqQjJ";
  
  #ifdef HAVE_TRUE_LONG_LONG
  /* It is intentional to use long long instead of LONG_LONG. */
  # define NATINT_LEN_Q NATINT_LEN(long long, 8)
  #else
  # define NATINT_LEN_Q 8
  #endif
  
  #if SIZEOF_SHORT != 2 || SIZEOF_LONG != 4 || (defined(HAVE_TRUE_LONG_LONG) && SIZEOF_LONG_LONG != 8)
  # define NATINT_PACK
  #endif
  
  #ifdef DYNAMIC_ENDIAN
   /* for universal binary of NEXTSTEP and MacOS X */
   /* useless since autoconf 2.63? */
   static int
   is_bigendian(void)
   {
       static int init = 0;
       static int endian_value;
       char *p;
  
       if (init) return endian_value;
       init = 1;
       p = (char*)&init;
       return endian_value = p[0]?0:1;
   }
  # define BIGENDIAN_P() (is_bigendian())
  #elif defined(WORDS_BIGENDIAN)
  # define BIGENDIAN_P() 1
  #else
  # define BIGENDIAN_P() 0
  #endif
  
  #ifdef NATINT_PACK
  # define NATINT_LEN(type,len) (natint?(int)sizeof(type):(int)(len))
  #else
  # define NATINT_LEN(type,len) ((int)sizeof(type))
  #endif
  
  typedef union {
      float f;
      uint32_t u;
      char buf[4];
  } FLOAT_SWAPPER;
  typedef union {
      double d;
      uint64_t u;
      char buf[8];
  } DOUBLE_SWAPPER;
  #define swapf(x) swap32(x)
  #define swapd(x) swap64(x)
  
  #define rb_ntohf(x) (BIGENDIAN_P()?(x):swapf(x))
  #define rb_ntohd(x) (BIGENDIAN_P()?(x):swapd(x))
  #define rb_htonf(x) (BIGENDIAN_P()?(x):swapf(x))
  #define rb_htond(x) (BIGENDIAN_P()?(x):swapd(x))
  #define rb_htovf(x) (BIGENDIAN_P()?swapf(x):(x))
  #define rb_htovd(x) (BIGENDIAN_P()?swapd(x):(x))
  #define rb_vtohf(x) (BIGENDIAN_P()?swapf(x):(x))
  #define rb_vtohd(x) (BIGENDIAN_P()?swapd(x):(x))
  
  #define FLOAT_CONVWITH(x)	FLOAT_SWAPPER x;
  #define HTONF(x)	((x).u = rb_htonf((x).u))
  #define HTOVF(x)	((x).u = rb_htovf((x).u))
  #define NTOHF(x)	((x).u = rb_ntohf((x).u))
  #define VTOHF(x)	((x).u = rb_vtohf((x).u))
  
  #define DOUBLE_CONVWITH(x)	DOUBLE_SWAPPER x;
  #define HTOND(x)	((x).u = rb_htond((x).u))
  #define HTOVD(x)	((x).u = rb_htovd((x).u))
  #define NTOHD(x)	((x).u = rb_ntohd((x).u))
  #define VTOHD(x)	((x).u = rb_vtohd((x).u))
  
  #define MAX_INTEGER_PACK_SIZE 8
  
  static const char toofew[] = "too few arguments";
  
  static void encodes(VALUE,const char*,long,int,int);
  static void qpencode(VALUE,VALUE,long);
  
  static unsigned long utf8_to_uv(const char*,long*);
  
  static ID id_associated;
  
  static void
  str_associate(VALUE str, VALUE add)
  {
      VALUE assoc;
  
      assoc = rb_attr_get(str, id_associated);
      if (RB_TYPE_P(assoc, T_ARRAY)) {
  	/* already associated */
  	rb_ary_concat(assoc, add);
      }
      else {
  	rb_ivar_set(str, id_associated, add);
      }
  }
  
  static VALUE
  str_associated(VALUE str)
  {
      VALUE assoc = rb_attr_get(str, id_associated);
      if (NIL_P(assoc)) assoc = Qfalse;
      return assoc;
  }
  
  void
  rb_str_associate(VALUE str, VALUE add)
  {
      rb_warn("rb_str_associate() is only for internal use and deprecated; do not use");
      str_associate(str, add);
  }
  
  VALUE
  rb_str_associated(VALUE str)
  {
      rb_warn("rb_str_associated() is only for internal use and deprecated; do not use");
      return str_associated(str);
  }
  
  /*
   *  call-seq:
   *     arr.pack ( aTemplateString ) -> aBinaryString
   *
   *  Packs the contents of <i>arr</i> into a binary sequence according to
   *  the directives in <i>aTemplateString</i> (see the table below)
   *  Directives ``A,'' ``a,'' and ``Z'' may be followed by a count,
   *  which gives the width of the resulting field. The remaining
   *  directives also may take a count, indicating the number of array
   *  elements to convert. If the count is an asterisk
   *  (``<code>*</code>''), all remaining array elements will be
   *  converted. Any of the directives ``<code>sSiIlL</code>'' may be
   *  followed by an underscore (``<code>_</code>'') or
   *  exclamation mark (``<code>!</code>'') to use the underlying
   *  platform's native size for the specified type; otherwise, they use a
   *  platform-independent size. Spaces are ignored in the template
   *  string. See also <code>String#unpack</code>.
   *
   *     a = [ "a", "b", "c" ]
   *     n = [ 65, 66, 67 ]
   *     a.pack("A3A3A3")   #=> "a  b  c  "
   *     a.pack("a3a3a3")   #=> "a\000\000b\000\000c\000\000"
   *     n.pack("ccc")      #=> "ABC"
   *
   *  Directives for +pack+.
   *
   *   Integer      | Array   |
   *   Directive    | Element | Meaning
   *   ---------------------------------------------------------------------------
   *      C         | Integer | 8-bit unsigned (unsigned char)
   *      S         | Integer | 16-bit unsigned, native endian (uint16_t)
   *      L         | Integer | 32-bit unsigned, native endian (uint32_t)
   *      Q         | Integer | 64-bit unsigned, native endian (uint64_t)
   *      J         | Integer | pointer width unsigned, native endian (uintptr_t)
   *                |         | (J is available since Ruby 2.3.)
   *                |         |
   *      c         | Integer | 8-bit signed (signed char)
   *      s         | Integer | 16-bit signed, native endian (int16_t)
   *      l         | Integer | 32-bit signed, native endian (int32_t)
   *      q         | Integer | 64-bit signed, native endian (int64_t)
   *      j         | Integer | pointer width signed, native endian (intptr_t)
   *                |         | (j is available since Ruby 2.3.)
   *                |         |
   *      S_, S!    | Integer | unsigned short, native endian
   *      I, I_, I! | Integer | unsigned int, native endian
   *      L_, L!    | Integer | unsigned long, native endian
   *      Q_, Q!    | Integer | unsigned long long, native endian (ArgumentError
   *                |         | if the platform has no long long type.)
   *                |         | (Q_ and Q! is available since Ruby 2.1.)
   *      J!        | Integer | uintptr_t, native endian (same with J)
   *                |         | (J! is available since Ruby 2.3.)
   *                |         |
   *      s_, s!    | Integer | signed short, native endian
   *      i, i_, i! | Integer | signed int, native endian
   *      l_, l!    | Integer | signed long, native endian
   *      q_, q!    | Integer | signed long long, native endian (ArgumentError
   *                |         | if the platform has no long long type.)
   *                |         | (q_ and q! is available since Ruby 2.1.)
   *      j!        | Integer | intptr_t, native endian (same with j)
   *                |         | (j! is available since Ruby 2.3.)
   *                |         |
   *      S> L> Q>  | Integer | same as the directives without ">" except
   *      J> s> l>  |         | big endian
   *      q> j>     |         | (available since Ruby 1.9.3)
   *      S!> I!>   |         | "S>" is same as "n"
   *      L!> Q!>   |         | "L>" is same as "N"
   *      J!> s!>   |         |
   *      i!> l!>   |         |
   *      q!> j!>   |         |
   *                |         |
   *      S< L< Q<  | Integer | same as the directives without "<" except
   *      J< s< l<  |         | little endian
   *      q< j<     |         | (available since Ruby 1.9.3)
   *      S!< I!<   |         | "S<" is same as "v"
   *      L!< Q!<   |         | "L<" is same as "V"
   *      J!< s!<   |         |
   *      i!< l!<   |         |
   *      q!< j!<   |         |
   *                |         |
   *      n         | Integer | 16-bit unsigned, network (big-endian) byte order
   *      N         | Integer | 32-bit unsigned, network (big-endian) byte order
   *      v         | Integer | 16-bit unsigned, VAX (little-endian) byte order
   *      V         | Integer | 32-bit unsigned, VAX (little-endian) byte order
   *                |         |
   *      U         | Integer | UTF-8 character
   *      w         | Integer | BER-compressed integer
   *
   *   Float        |         |
   *   Directive    |         | Meaning
   *   ---------------------------------------------------------------------------
   *      D, d      | Float   | double-precision, native format
   *      F, f      | Float   | single-precision, native format
   *      E         | Float   | double-precision, little-endian byte order
   *      e         | Float   | single-precision, little-endian byte order
   *      G         | Float   | double-precision, network (big-endian) byte order
   *      g         | Float   | single-precision, network (big-endian) byte order
   *
   *   String       |         |
   *   Directive    |         | Meaning
   *   ---------------------------------------------------------------------------
   *      A         | String  | arbitrary binary string (space padded, count is width)
   *      a         | String  | arbitrary binary string (null padded, count is width)
   *      Z         | String  | same as ``a'', except that null is added with *
   *      B         | String  | bit string (MSB first)
   *      b         | String  | bit string (LSB first)
   *      H         | String  | hex string (high nibble first)
   *      h         | String  | hex string (low nibble first)
   *      u         | String  | UU-encoded string
   *      M         | String  | quoted printable, MIME encoding (see RFC2045)
   *      m         | String  | base64 encoded string (see RFC 2045, count is width)
   *                |         | (if count is 0, no line feed are added, see RFC 4648)
   *      P         | String  | pointer to a structure (fixed-length string)
   *      p         | String  | pointer to a null-terminated string
   *
   *   Misc.        |         |
   *   Directive    |         | Meaning
   *   ---------------------------------------------------------------------------
   *      @         | ---     | moves to absolute position
   *      X         | ---     | back up a byte
   *      x         | ---     | null byte
   */
  
  static VALUE
  pack_pack(VALUE ary, VALUE fmt)
  {
      static const char nul10[] = "\0\0\0\0\0\0\0\0\0\0";
      static const char spc10[] = "          ";
      const char *p, *pend;
      VALUE res, from, associates = 0;
      char type;
      long len, idx, plen;
      const char *ptr;
      int enc_info = 1;		/* 0 - BINARY, 1 - US-ASCII, 2 - UTF-8 */
  #ifdef NATINT_PACK
      int natint;		/* native integer */
  #endif
      int integer_size, bigendian_p;
  
      StringValue(fmt);
      p = RSTRING_PTR(fmt);
      pend = p + RSTRING_LEN(fmt);
      res = rb_str_buf_new(0);
  
      idx = 0;
  
  #define TOO_FEW (rb_raise(rb_eArgError, toofew), 0)
  #define MORE_ITEM (idx < RARRAY_LEN(ary))
  #define THISFROM (MORE_ITEM ? RARRAY_AREF(ary, idx) : TOO_FEW)
  #define NEXTFROM (MORE_ITEM ? RARRAY_AREF(ary, idx++) : TOO_FEW)
  
      while (p < pend) {
  	int explicit_endian = 0;
  	if (RSTRING_PTR(fmt) + RSTRING_LEN(fmt) != pend) {
  	    rb_raise(rb_eRuntimeError, "format string modified");
  	}
  	type = *p++;		/* get data type */
  #ifdef NATINT_PACK
  	natint = 0;
  #endif
  
  	if (ISSPACE(type)) continue;
  	if (type == '#') {
  	    while ((p < pend) && (*p != '\n')) {
  		p++;
  	    }
  	    continue;
  	}
  
  	{
            modifiers:
  	    switch (*p) {
  	      case '_':
  	      case '!':
  		if (strchr(natstr, type)) {
  #ifdef NATINT_PACK
  		    natint = 1;
  #endif
  		    p++;
  		}
  		else {
  		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, natstr);
  		}
  		goto modifiers;
  
  	      case '<':
  	      case '>':
  		if (!strchr(endstr, type)) {
  		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, endstr);
  		}
  		if (explicit_endian) {
  		    rb_raise(rb_eRangeError, "Can't use both '<' and '>'");
  		}
  		explicit_endian = *p++;
  		goto modifiers;
  	    }
  	}
  
  	if (*p == '*') {	/* set data length */
  	    len = strchr("@Xxu", type) ? 0
                  : strchr("PMm", type) ? 1
                  : RARRAY_LEN(ary) - idx;
  	    p++;
  	}
  	else if (ISDIGIT(*p)) {
  	    errno = 0;
  	    len = STRTOUL(p, (char**)&p, 10);
  	    if (errno) {
  		rb_raise(rb_eRangeError, "pack length too big");
  	    }
  	}
  	else {
  	    len = 1;
  	}
  
  	switch (type) {
  	  case 'U':
  	    /* if encoding is US-ASCII, upgrade to UTF-8 */
  	    if (enc_info == 1) enc_info = 2;
  	    break;
  	  case 'm': case 'M': case 'u':
  	    /* keep US-ASCII (do nothing) */
  	    break;
  	  default:
  	    /* fall back to BINARY */
  	    enc_info = 0;
  	    break;
  	}
  	switch (type) {
  	  case 'A': case 'a': case 'Z':
  	  case 'B': case 'b':
  	  case 'H': case 'h':
  	    from = NEXTFROM;
  	    if (NIL_P(from)) {
  		ptr = "";
  		plen = 0;
  	    }
  	    else {
  		StringValue(from);
  		ptr = RSTRING_PTR(from);
  		plen = RSTRING_LEN(from);
  		OBJ_INFECT(res, from);
  	    }
  
  	    if (p[-1] == '*')
  		len = plen;
  
  	    switch (type) {
  	      case 'a':		/* arbitrary binary string (null padded)  */
  	      case 'A':         /* arbitrary binary string (ASCII space padded) */
  	      case 'Z':         /* null terminated string  */
  		if (plen >= len) {
  		    rb_str_buf_cat(res, ptr, len);
  		    if (p[-1] == '*' && type == 'Z')
  			rb_str_buf_cat(res, nul10, 1);
  		}
  		else {
  		    rb_str_buf_cat(res, ptr, plen);
  		    len -= plen;
  		    while (len >= 10) {
  			rb_str_buf_cat(res, (type == 'A')?spc10:nul10, 10);
  			len -= 10;
  		    }
  		    rb_str_buf_cat(res, (type == 'A')?spc10:nul10, len);
  		}
  		break;
  
  #define castchar(from) (char)((from) & 0xff)
  
  	      case 'b':		/* bit string (ascending) */
  		{
  		    int byte = 0;
  		    long i, j = 0;
  
  		    if (len > plen) {
  			j = (len - plen + 1)/2;
  			len = plen;
  		    }
  		    for (i=0; i++ < len; ptr++) {
  			if (*ptr & 1)
  			    byte |= 128;
  			if (i & 7)
  			    byte >>= 1;
  			else {
  			    char c = castchar(byte);
  			    rb_str_buf_cat(res, &c, 1);
  			    byte = 0;
  			}
  		    }
  		    if (len & 7) {
  			char c;
  			byte >>= 7 - (len & 7);
  			c = castchar(byte);
  			rb_str_buf_cat(res, &c, 1);
  		    }
  		    len = j;
  		    goto grow;
  		}
  		break;
  
  	      case 'B':		/* bit string (descending) */
  		{
  		    int byte = 0;
  		    long i, j = 0;
  
  		    if (len > plen) {
  			j = (len - plen + 1)/2;
  			len = plen;
  		    }
  		    for (i=0; i++ < len; ptr++) {
  			byte |= *ptr & 1;
  			if (i & 7)
  			    byte <<= 1;
  			else {
  			    char c = castchar(byte);
  			    rb_str_buf_cat(res, &c, 1);
  			    byte = 0;
  			}
  		    }
  		    if (len & 7) {
  			char c;
  			byte <<= 7 - (len & 7);
  			c = castchar(byte);
  			rb_str_buf_cat(res, &c, 1);
  		    }
  		    len = j;
  		    goto grow;
  		}
  		break;
  
  	      case 'h':		/* hex string (low nibble first) */
  		{
  		    int byte = 0;
  		    long i, j = 0;
  
  		    if (len > plen) {
  			j = (len + 1) / 2 - (plen + 1) / 2;
  			len = plen;
  		    }
  		    for (i=0; i++ < len; ptr++) {
  			if (ISALPHA(*ptr))
  			    byte |= (((*ptr & 15) + 9) & 15) << 4;
  			else
  			    byte |= (*ptr & 15) << 4;
  			if (i & 1)
  			    byte >>= 4;
  			else {
  			    char c = castchar(byte);
  			    rb_str_buf_cat(res, &c, 1);
  			    byte = 0;
  			}
  		    }
  		    if (len & 1) {
  			char c = castchar(byte);
  			rb_str_buf_cat(res, &c, 1);
  		    }
  		    len = j;
  		    goto grow;
  		}
  		break;
  
  	      case 'H':		/* hex string (high nibble first) */
  		{
  		    int byte = 0;
  		    long i, j = 0;
  
  		    if (len > plen) {
  			j = (len + 1) / 2 - (plen + 1) / 2;
  			len = plen;
  		    }
  		    for (i=0; i++ < len; ptr++) {
  			if (ISALPHA(*ptr))
  			    byte |= ((*ptr & 15) + 9) & 15;
  			else
  			    byte |= *ptr & 15;
  			if (i & 1)
  			    byte <<= 4;
  			else {
  			    char c = castchar(byte);
  			    rb_str_buf_cat(res, &c, 1);
  			    byte = 0;
  			}
  		    }
  		    if (len & 1) {
  			char c = castchar(byte);
  			rb_str_buf_cat(res, &c, 1);
  		    }
  		    len = j;
  		    goto grow;
  		}
  		break;
  	    }
  	    break;
  
  	  case 'c':		/* signed char */
  	  case 'C':		/* unsigned char */
              integer_size = 1;
              bigendian_p = BIGENDIAN_P(); /* not effective */
              goto pack_integer;
  
  	  case 's':		/* s for int16_t, s! for signed short */
              integer_size = NATINT_LEN(short, 2);
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'S':		/* S for uint16_t, S! for unsigned short */
              integer_size = NATINT_LEN(short, 2);
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'i':		/* i and i! for signed int */
              integer_size = (int)sizeof(int);
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'I':		/* I and I! for unsigned int */
              integer_size = (int)sizeof(int);
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'l':		/* l for int32_t, l! for signed long */
              integer_size = NATINT_LEN(long, 4);
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'L':		/* L for uint32_t, L! for unsigned long */
              integer_size = NATINT_LEN(long, 4);
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'q':		/* q for int64_t, q! for signed long long */
  	    integer_size = NATINT_LEN_Q;
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'Q':		/* Q for uint64_t, Q! for unsigned long long */
  	    integer_size = NATINT_LEN_Q;
              bigendian_p = BIGENDIAN_P();
              goto pack_integer;
  
  	  case 'j':		/* j for intptr_t */
  	    integer_size = sizeof(intptr_t);
  	    bigendian_p = BIGENDIAN_P();
  	    goto pack_integer;
  
  	  case 'J':		/* J for uintptr_t */
  	    integer_size = sizeof(uintptr_t);
  	    bigendian_p = BIGENDIAN_P();
  	    goto pack_integer;
  
  	  case 'n':		/* 16 bit (2 bytes) integer (network byte-order)  */
              integer_size = 2;
              bigendian_p = 1;
              goto pack_integer;
  
  	  case 'N':		/* 32 bit (4 bytes) integer (network byte-order) */
              integer_size = 4;
              bigendian_p = 1;
              goto pack_integer;
  
  	  case 'v':		/* 16 bit (2 bytes) integer (VAX byte-order) */
              integer_size = 2;
              bigendian_p = 0;
              goto pack_integer;
  
  	  case 'V':		/* 32 bit (4 bytes) integer (VAX byte-order) */
              integer_size = 4;
              bigendian_p = 0;
              goto pack_integer;
  
            pack_integer:
  	    if (explicit_endian) {
  		bigendian_p = explicit_endian == '>';
  	    }
              if (integer_size > MAX_INTEGER_PACK_SIZE)
                  rb_bug("unexpected intger size for pack: %d", integer_size);
              while (len-- > 0) {
                  char intbuf[MAX_INTEGER_PACK_SIZE];
  
                  from = NEXTFROM;
                  rb_integer_pack(from, intbuf, integer_size, 1, 0,
                      INTEGER_PACK_2COMP |
                      (bigendian_p ? INTEGER_PACK_BIG_ENDIAN : INTEGER_PACK_LITTLE_ENDIAN));
                  rb_str_buf_cat(res, intbuf, integer_size);
              }
  	    break;
  
  	  case 'f':		/* single precision float in native format */
  	  case 'F':		/* ditto */
  	    while (len-- > 0) {
  		float f;
  
  		from = NEXTFROM;
  		f = (float)RFLOAT_VALUE(rb_to_float(from));
  		rb_str_buf_cat(res, (char*)&f, sizeof(float));
  	    }
  	    break;
  
  	  case 'e':		/* single precision float in VAX byte-order */
  	    while (len-- > 0) {
  		FLOAT_CONVWITH(tmp);
  
  		from = NEXTFROM;
  		tmp.f = (float)RFLOAT_VALUE(rb_to_float(from));
  		HTOVF(tmp);
  		rb_str_buf_cat(res, tmp.buf, sizeof(float));
  	    }
  	    break;
  
  	  case 'E':		/* double precision float in VAX byte-order */
  	    while (len-- > 0) {
  		DOUBLE_CONVWITH(tmp);
  		from = NEXTFROM;
  		tmp.d = RFLOAT_VALUE(rb_to_float(from));
  		HTOVD(tmp);
  		rb_str_buf_cat(res, tmp.buf, sizeof(double));
  	    }
  	    break;
  
  	  case 'd':		/* double precision float in native format */
  	  case 'D':		/* ditto */
  	    while (len-- > 0) {
  		double d;
  
  		from = NEXTFROM;
  		d = RFLOAT_VALUE(rb_to_float(from));
  		rb_str_buf_cat(res, (char*)&d, sizeof(double));
  	    }
  	    break;
  
  	  case 'g':		/* single precision float in network byte-order */
  	    while (len-- > 0) {
  		FLOAT_CONVWITH(tmp);
  		from = NEXTFROM;
  		tmp.f = (float)RFLOAT_VALUE(rb_to_float(from));
  		HTONF(tmp);
  		rb_str_buf_cat(res, tmp.buf, sizeof(float));
  	    }
  	    break;
  
  	  case 'G':		/* double precision float in network byte-order */
  	    while (len-- > 0) {
  		DOUBLE_CONVWITH(tmp);
  
  		from = NEXTFROM;
  		tmp.d = RFLOAT_VALUE(rb_to_float(from));
  		HTOND(tmp);
  		rb_str_buf_cat(res, tmp.buf, sizeof(double));
  	    }
  	    break;
  
  	  case 'x':		/* null byte */
  	  grow:
  	    while (len >= 10) {
  		rb_str_buf_cat(res, nul10, 10);
  		len -= 10;
  	    }
  	    rb_str_buf_cat(res, nul10, len);
  	    break;
  
  	  case 'X':		/* back up byte */
  	  shrink:
  	    plen = RSTRING_LEN(res);
  	    if (plen < len)
  		rb_raise(rb_eArgError, "X outside of string");
  	    rb_str_set_len(res, plen - len);
  	    break;
  
  	  case '@':		/* null fill to absolute position */
  	    len -= RSTRING_LEN(res);
  	    if (len > 0) goto grow;
  	    len = -len;
  	    if (len > 0) goto shrink;
  	    break;
  
  	  case '%':
  	    rb_raise(rb_eArgError, "%% is not supported");
  	    break;
  
  	  case 'U':		/* Unicode character */
  	    while (len-- > 0) {
  		SIGNED_VALUE l;
  		char buf[8];
  		int le;
  
  		from = NEXTFROM;
  		from = rb_to_int(from);
  		l = NUM2LONG(from);
  		if (l < 0) {
  		    rb_raise(rb_eRangeError, "pack(U): value out of range");
  		}
  		le = rb_uv_to_utf8(buf, l);
  		rb_str_buf_cat(res, (char*)buf, le);
  	    }
  	    break;
  
  	  case 'u':		/* uuencoded string */
  	  case 'm':		/* base64 encoded string */
  	    from = NEXTFROM;
  	    StringValue(from);
  	    ptr = RSTRING_PTR(from);
  	    plen = RSTRING_LEN(from);
  
  	    if (len == 0 && type == 'm') {
  		encodes(res, ptr, plen, type, 0);
  		ptr += plen;
  		break;
  	    }
  	    if (len <= 2)
  		len = 45;
  	    else if (len > 63 && type == 'u')
  		len = 63;
  	    else
  		len = len / 3 * 3;
  	    while (plen > 0) {
  		long todo;
  
  		if (plen > len)
  		    todo = len;
  		else
  		    todo = plen;
  		encodes(res, ptr, todo, type, 1);
  		plen -= todo;
  		ptr += todo;
  	    }
  	    break;
  
  	  case 'M':		/* quoted-printable encoded string */
  	    from = rb_obj_as_string(NEXTFROM);
  	    if (len <= 1)
  		len = 72;
  	    qpencode(res, from, len);
  	    break;
  
  	  case 'P':		/* pointer to packed byte string */
  	    from = THISFROM;
  	    if (!NIL_P(from)) {
  		StringValue(from);
  		if (RSTRING_LEN(from) < len) {
  		    rb_raise(rb_eArgError, "too short buffer for P(%ld for %ld)",
  			     RSTRING_LEN(from), len);
  		}
  	    }
  	    len = 1;
  	    /* FALL THROUGH */
  	  case 'p':		/* pointer to string */
  	    while (len-- > 0) {
  		char *t;
  		from = NEXTFROM;
  		if (NIL_P(from)) {
  		    t = 0;
  		}
  		else {
  		    t = StringValuePtr(from);
  		    rb_obj_taint(from);
  		}
  		if (!associates) {
  		    associates = rb_ary_new();
  		}
  		rb_ary_push(associates, from);
  		rb_str_buf_cat(res, (char*)&t, sizeof(char*));
  	    }
  	    break;
  
  	  case 'w':		/* BER compressed integer  */
  	    while (len-- > 0) {
  		VALUE buf = rb_str_new(0, 0);
                  size_t numbytes;
                  int sign;
                  char *cp;
  
  		from = NEXTFROM;
                  from = rb_to_int(from);
                  numbytes = rb_absint_numwords(from, 7, NULL);
                  if (numbytes == 0)
                      numbytes = 1;
                  buf = rb_str_new(NULL, numbytes);
  
                  sign = rb_integer_pack(from, RSTRING_PTR(buf), RSTRING_LEN(buf), 1, 1, INTEGER_PACK_BIG_ENDIAN);
  
                  if (sign < 0)
                      rb_raise(rb_eArgError, "can't compress negative numbers");
                  if (sign == 2)
                      rb_bug("buffer size problem?");
  
                  cp = RSTRING_PTR(buf);
                  while (1 < numbytes) {
                    *cp |= 0x80;
                    cp++;
                    numbytes--;
                  }
  
                  rb_str_buf_cat(res, RSTRING_PTR(buf), RSTRING_LEN(buf));
  	    }
  	    break;
  
  	  default: {
  	    char unknown[5];
  	    if (ISPRINT(type)) {
  		unknown[0] = type;
  		unknown[1] = '\0';
  	    }
  	    else {
  		snprintf(unknown, sizeof(unknown), "\\x%.2x", type & 0xff);
  	    }
  	    rb_warning("unknown pack directive '%s' in '% "PRIsVALUE"'",
  		       unknown, fmt);
  	    break;
  	  }
  	}
      }
  
      if (associates) {
  	str_associate(res, associates);
      }
      OBJ_INFECT(res, fmt);
      switch (enc_info) {
        case 1:
  	ENCODING_CODERANGE_SET(res, rb_usascii_encindex(), ENC_CODERANGE_7BIT);
  	break;
        case 2:
  	rb_enc_set_index(res, rb_utf8_encindex());
  	break;
        default:
  	/* do nothing, keep ASCII-8BIT */
  	break;
      }
      return res;
  }
  
  static const char uu_table[] =
  "`!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_";
  static const char b64_table[] =
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  static void
  encodes(VALUE str, const char *s0, long len, int type, int tail_lf)
  {
      enum {buff_size = 4096, encoded_unit = 4, input_unit = 3};
      char buff[buff_size + 1];	/* +1 for tail_lf */
      long i = 0;
      const char *const trans = type == 'u' ? uu_table : b64_table;
      char padding;
      const unsigned char *s = (const unsigned char *)s0;
  
      if (type == 'u') {
  	buff[i++] = (char)len + ' ';
  	padding = '`';
      }
      else {
  	padding = '=';
      }
      while (len >= input_unit) {
          while (len >= input_unit && buff_size-i >= encoded_unit) {
              buff[i++] = trans[077 & (*s >> 2)];
              buff[i++] = trans[077 & (((*s << 4) & 060) | ((s[1] >> 4) & 017))];
              buff[i++] = trans[077 & (((s[1] << 2) & 074) | ((s[2] >> 6) & 03))];
              buff[i++] = trans[077 & s[2]];
              s += input_unit;
              len -= input_unit;
          }
          if (buff_size-i < encoded_unit) {
              rb_str_buf_cat(str, buff, i);
              i = 0;
          }
      }
  
      if (len == 2) {
  	buff[i++] = trans[077 & (*s >> 2)];
  	buff[i++] = trans[077 & (((*s << 4) & 060) | ((s[1] >> 4) & 017))];
  	buff[i++] = trans[077 & (((s[1] << 2) & 074) | (('\0' >> 6) & 03))];
  	buff[i++] = padding;
      }
      else if (len == 1) {
  	buff[i++] = trans[077 & (*s >> 2)];
  	buff[i++] = trans[077 & (((*s << 4) & 060) | (('\0' >> 4) & 017))];
  	buff[i++] = padding;
  	buff[i++] = padding;
      }
      if (tail_lf) buff[i++] = '\n';
      rb_str_buf_cat(str, buff, i);
      if ((size_t)i > sizeof(buff)) rb_bug("encodes() buffer overrun");
  }
  
  static const char hex_table[] = "0123456789ABCDEF";
  
  static void
  qpencode(VALUE str, VALUE from, long len)
  {
      char buff[1024];
      long i = 0, n = 0, prev = EOF;
      unsigned char *s = (unsigned char*)RSTRING_PTR(from);
      unsigned char *send = s + RSTRING_LEN(from);
  
      while (s < send) {
          if ((*s > 126) ||
  	    (*s < 32 && *s != '\n' && *s != '\t') ||
  	    (*s == '=')) {
  	    buff[i++] = '=';
  	    buff[i++] = hex_table[*s >> 4];
  	    buff[i++] = hex_table[*s & 0x0f];
              n += 3;
              prev = EOF;
          }
  	else if (*s == '\n') {
              if (prev == ' ' || prev == '\t') {
  		buff[i++] = '=';
  		buff[i++] = *s;
              }
  	    buff[i++] = *s;
              n = 0;
              prev = *s;
          }
  	else {
  	    buff[i++] = *s;
              n++;
              prev = *s;
          }
          if (n > len) {
  	    buff[i++] = '=';
  	    buff[i++] = '\n';
              n = 0;
              prev = '\n';
          }
  	if (i > 1024 - 5) {
  	    rb_str_buf_cat(str, buff, i);
  	    i = 0;
  	}
  	s++;
      }
      if (n > 0) {
  	buff[i++] = '=';
  	buff[i++] = '\n';
      }
      if (i > 0) {
  	rb_str_buf_cat(str, buff, i);
      }
  }
  
  static inline int
  hex2num(char c)
  {
      int n;
      n = ruby_digit36_to_number_table[(unsigned char)c];
      if (16 <= n)
          n = -1;
      return n;
  }
  
  #define PACK_LENGTH_ADJUST_SIZE(sz) do {	\
      tmp_len = 0;				\
      if (len > (long)((send-s)/(sz))) {		\
          if (!star) {				\
  	    tmp_len = len-(send-s)/(sz);		\
          }					\
  	len = (send-s)/(sz);			\
      }						\
  } while (0)
  
  #define PACK_ITEM_ADJUST() do { \
      if (tmp_len > 0 && !block_p) \
  	rb_ary_store(ary, RARRAY_LEN(ary)+tmp_len-1, Qnil); \
  } while (0)
  
  /* Workaround for Oracle Solaris Studio 12.4 C compiler optimization bug
   * with "-xO4" optimization option.
   */
  #if defined(__SUNPRO_C) && __SUNPRO_C == 0x5130
  # define AVOID_CC_BUG volatile
  #else
  # define AVOID_CC_BUG
  #endif
  
  static VALUE
  infected_str_new(const char *ptr, long len, VALUE str)
  {
      VALUE s = rb_str_new(ptr, len);
  
      OBJ_INFECT(s, str);
      return s;
  }
  
  /*
   *  call-seq:
   *     str.unpack(format)    ->  anArray
   *
   *  Decodes <i>str</i> (which may contain binary data) according to the
   *  format string, returning an array of each value extracted. The
   *  format string consists of a sequence of single-character directives,
   *  summarized in the table at the end of this entry.
   *  Each directive may be followed
   *  by a number, indicating the number of times to repeat with this
   *  directive. An asterisk (``<code>*</code>'') will use up all
   *  remaining elements. The directives <code>sSiIlL</code> may each be
   *  followed by an underscore (``<code>_</code>'') or
   *  exclamation mark (``<code>!</code>'') to use the underlying
   *  platform's native size for the specified type; otherwise, it uses a
   *  platform-independent consistent size. Spaces are ignored in the
   *  format string. See also <code>Array#pack</code>.
   *
   *     "abc \0\0abc \0\0".unpack('A6Z6')   #=> ["abc", "abc "]
   *     "abc \0\0".unpack('a3a3')           #=> ["abc", " \000\000"]
   *     "abc \0abc \0".unpack('Z*Z*')       #=> ["abc ", "abc "]
   *     "aa".unpack('b8B8')                 #=> ["10000110", "01100001"]
   *     "aaa".unpack('h2H2c')               #=> ["16", "61", 97]
   *     "\xfe\xff\xfe\xff".unpack('sS')     #=> [-2, 65534]
   *     "now=20is".unpack('M*')             #=> ["now is"]
   *     "whole".unpack('xax2aX2aX1aX2a')    #=> ["h", "e", "l", "l", "o"]
   *
   *  This table summarizes the various formats and the Ruby classes
   *  returned by each.
   *
   *   Integer      |         |
   *   Directive    | Returns | Meaning
   *   -----------------------------------------------------------------
   *      C         | Integer | 8-bit unsigned (unsigned char)
   *      S         | Integer | 16-bit unsigned, native endian (uint16_t)
   *      L         | Integer | 32-bit unsigned, native endian (uint32_t)
   *      Q         | Integer | 64-bit unsigned, native endian (uint64_t)
   *                |         |
   *      c         | Integer | 8-bit signed (signed char)
   *      s         | Integer | 16-bit signed, native endian (int16_t)
   *      l         | Integer | 32-bit signed, native endian (int32_t)
   *      q         | Integer | 64-bit signed, native endian (int64_t)
   *                |         |
   *      S_, S!    | Integer | unsigned short, native endian
   *      I, I_, I! | Integer | unsigned int, native endian
   *      L_, L!    | Integer | unsigned long, native endian
   *      Q_, Q!    | Integer | unsigned long long, native endian (ArgumentError
   *                |         | if the platform has no long long type.)
   *                |         | (Q_ and Q! is available since Ruby 2.1.)
   *                |         |
   *      s_, s!    | Integer | signed short, native endian
   *      i, i_, i! | Integer | signed int, native endian
   *      l_, l!    | Integer | signed long, native endian
   *      q_, q!    | Integer | signed long long, native endian (ArgumentError
   *                |         | if the platform has no long long type.)
   *                |         | (q_ and q! is available since Ruby 2.1.)
   *                |         |
   *      S> L> Q>  | Integer | same as the directives without ">" except
   *      s> l> q>  |         | big endian
   *      S!> I!>   |         | (available since Ruby 1.9.3)
   *      L!> Q!>   |         | "S>" is same as "n"
   *      s!> i!>   |         | "L>" is same as "N"
   *      l!> q!>   |         |
   *                |         |
   *      S< L< Q<  | Integer | same as the directives without "<" except
   *      s< l< q<  |         | little endian
   *      S!< I!<   |         | (available since Ruby 1.9.3)
   *      L!< Q!<   |         | "S<" is same as "v"
   *      s!< i!<   |         | "L<" is same as "V"
   *      l!< q!<   |         |
   *                |         |
   *      n         | Integer | 16-bit unsigned, network (big-endian) byte order
   *      N         | Integer | 32-bit unsigned, network (big-endian) byte order
   *      v         | Integer | 16-bit unsigned, VAX (little-endian) byte order
   *      V         | Integer | 32-bit unsigned, VAX (little-endian) byte order
   *                |         |
   *      U         | Integer | UTF-8 character
   *      w         | Integer | BER-compressed integer (see Array.pack)
   *
   *   Float        |         |
   *   Directive    | Returns | Meaning
   *   -----------------------------------------------------------------
   *      D, d      | Float   | double-precision, native format
   *      F, f      | Float   | single-precision, native format
   *      E         | Float   | double-precision, little-endian byte order
   *      e         | Float   | single-precision, little-endian byte order
   *      G         | Float   | double-precision, network (big-endian) byte order
   *      g         | Float   | single-precision, network (big-endian) byte order
   *
   *   String       |         |
   *   Directive    | Returns | Meaning
   *   -----------------------------------------------------------------
   *      A         | String  | arbitrary binary string (remove trailing nulls and ASCII spaces)
   *      a         | String  | arbitrary binary string
   *      Z         | String  | null-terminated string
   *      B         | String  | bit string (MSB first)
   *      b         | String  | bit string (LSB first)
   *      H         | String  | hex string (high nibble first)
   *      h         | String  | hex string (low nibble first)
   *      u         | String  | UU-encoded string
   *      M         | String  | quoted-printable, MIME encoding (see RFC2045)
   *      m         | String  | base64 encoded string (RFC 2045) (default)
   *                |         | base64 encoded string (RFC 4648) if followed by 0
   *      P         | String  | pointer to a structure (fixed-length string)
   *      p         | String  | pointer to a null-terminated string
   *
   *   Misc.        |         |
   *   Directive    | Returns | Meaning
   *   -----------------------------------------------------------------
   *      @         | ---     | skip to the offset given by the length argument
   *      X         | ---     | skip backward one byte
   *      x         | ---     | skip forward one byte
   */
  
  static VALUE
  pack_unpack(VALUE str, VALUE fmt)
  {
  #define hexdigits ruby_hexdigits
      char *s, *send;
      char *p, *pend;
      VALUE ary;
      char type;
      long len;
      AVOID_CC_BUG long tmp_len;
      int star;
  #ifdef NATINT_PACK
      int natint;			/* native integer */
  #endif
      int block_p = rb_block_given_p();
      int signed_p, integer_size, bigendian_p;
  #define UNPACK_PUSH(item) do {\
  	VALUE item_val = (item);\
  	if (block_p) {\
  	    rb_yield(item_val);\
  	}\
  	else {\
  	    rb_ary_push(ary, item_val);\
  	}\
      } while (0)
  
      StringValue(str);
      StringValue(fmt);
      s = RSTRING_PTR(str);
      send = s + RSTRING_LEN(str);
      p = RSTRING_PTR(fmt);
      pend = p + RSTRING_LEN(fmt);
  
      ary = block_p ? Qnil : rb_ary_new();
      while (p < pend) {
  	int explicit_endian = 0;
  	type = *p++;
  #ifdef NATINT_PACK
  	natint = 0;
  #endif
  
  	if (ISSPACE(type)) continue;
  	if (type == '#') {
  	    while ((p < pend) && (*p != '\n')) {
  		p++;
  	    }
  	    continue;
  	}
  
  	star = 0;
  	{
            modifiers:
  	    switch (*p) {
  	      case '_':
  	      case '!':
  
  		if (strchr(natstr, type)) {
  #ifdef NATINT_PACK
  		    natint = 1;
  #endif
  		    p++;
  		}
  		else {
  		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, natstr);
  		}
  		goto modifiers;
  
  	      case '<':
  	      case '>':
  		if (!strchr(endstr, type)) {
  		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, endstr);
  		}
  		if (explicit_endian) {
  		    rb_raise(rb_eRangeError, "Can't use both '<' and '>'");
  		}
  		explicit_endian = *p++;
  		goto modifiers;
  	    }
  	}
  
  	if (p >= pend)
  	    len = 1;
  	else if (*p == '*') {
  	    star = 1;
  	    len = send - s;
  	    p++;
  	}
  	else if (ISDIGIT(*p)) {
  	    errno = 0;
  	    len = STRTOUL(p, (char**)&p, 10);
  	    if (errno) {
  		rb_raise(rb_eRangeError, "pack length too big");
  	    }
  	}
  	else {
  	    len = (type != '@');
  	}
  
  	switch (type) {
  	  case '%':
  	    rb_raise(rb_eArgError, "%% is not supported");
  	    break;
  
  	  case 'A':
  	    if (len > send - s) len = send - s;
  	    {
  		long end = len;
  		char *t = s + len - 1;
  
  		while (t >= s) {
  		    if (*t != ' ' && *t != '\0') break;
  		    t--; len--;
  		}
  		UNPACK_PUSH(infected_str_new(s, len, str));
  		s += end;
  	    }
  	    break;
  
  	  case 'Z':
  	    {
  		char *t = s;
  
  		if (len > send-s) len = send-s;
  		while (t < s+len && *t) t++;
  		UNPACK_PUSH(infected_str_new(s, t-s, str));
  		if (t < send) t++;
  		s = star ? t : s+len;
  	    }
  	    break;
  
  	  case 'a':
  	    if (len > send - s) len = send - s;
  	    UNPACK_PUSH(infected_str_new(s, len, str));
  	    s += len;
  	    break;
  
  	  case 'b':
  	    {
  		VALUE bitstr;
  		char *t;
  		int bits;
  		long i;
  
  		if (p[-1] == '*' || len > (send - s) * 8)
  		    len = (send - s) * 8;
  		bits = 0;
  		bitstr = rb_usascii_str_new(0, len);
  		t = RSTRING_PTR(bitstr);
  		for (i=0; i<len; i++) {
  		    if (i & 7) bits >>= 1;
  		    else bits = (unsigned char)*s++;
  		    *t++ = (bits & 1) ? '1' : '0';
  		}
  		UNPACK_PUSH(bitstr);
  	    }
  	    break;
  
  	  case 'B':
  	    {
  		VALUE bitstr;
  		char *t;
  		int bits;
  		long i;
  
  		if (p[-1] == '*' || len > (send - s) * 8)
  		    len = (send - s) * 8;
  		bits = 0;
  		bitstr = rb_usascii_str_new(0, len);
  		t = RSTRING_PTR(bitstr);
  		for (i=0; i<len; i++) {
  		    if (i & 7) bits <<= 1;
  		    else bits = (unsigned char)*s++;
  		    *t++ = (bits & 128) ? '1' : '0';
  		}
  		UNPACK_PUSH(bitstr);
  	    }
  	    break;
  
  	  case 'h':
  	    {
  		VALUE bitstr;
  		char *t;
  		int bits;
  		long i;
  
  		if (p[-1] == '*' || len > (send - s) * 2)
  		    len = (send - s) * 2;
  		bits = 0;
  		bitstr = rb_usascii_str_new(0, len);
  		t = RSTRING_PTR(bitstr);
  		for (i=0; i<len; i++) {
  		    if (i & 1)
  			bits >>= 4;
  		    else
  			bits = (unsigned char)*s++;
  		    *t++ = hexdigits[bits & 15];
  		}
  		UNPACK_PUSH(bitstr);
  	    }
  	    break;
  
  	  case 'H':
  	    {
  		VALUE bitstr;
  		char *t;
  		int bits;
  		long i;
  
  		if (p[-1] == '*' || len > (send - s) * 2)
  		    len = (send - s) * 2;
  		bits = 0;
  		bitstr = rb_usascii_str_new(0, len);
  		t = RSTRING_PTR(bitstr);
  		for (i=0; i<len; i++) {
  		    if (i & 1)
  			bits <<= 4;
  		    else
  			bits = (unsigned char)*s++;
  		    *t++ = hexdigits[(bits >> 4) & 15];
  		}
  		UNPACK_PUSH(bitstr);
  	    }
  	    break;
  
  	  case 'c':
  	    signed_p = 1;
  	    integer_size = 1;
  	    bigendian_p = BIGENDIAN_P(); /* not effective */
  	    goto unpack_integer;
  
  	  case 'C':
  	    signed_p = 0;
  	    integer_size = 1;
  	    bigendian_p = BIGENDIAN_P(); /* not effective */
  	    goto unpack_integer;
  
  	  case 's':
  	    signed_p = 1;
  	    integer_size = NATINT_LEN(short, 2);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'S':
  	    signed_p = 0;
  	    integer_size = NATINT_LEN(short, 2);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'i':
  	    signed_p = 1;
  	    integer_size = (int)sizeof(int);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'I':
  	    signed_p = 0;
  	    integer_size = (int)sizeof(int);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'l':
  	    signed_p = 1;
  	    integer_size = NATINT_LEN(long, 4);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'L':
  	    signed_p = 0;
  	    integer_size = NATINT_LEN(long, 4);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'q':
  	    signed_p = 1;
  	    integer_size = NATINT_LEN_Q;
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'Q':
  	    signed_p = 0;
  	    integer_size = NATINT_LEN_Q;
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'j':
  	    signed_p = 1;
  	    integer_size = sizeof(intptr_t);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'J':
  	    signed_p = 0;
  	    integer_size = sizeof(uintptr_t);
  	    bigendian_p = BIGENDIAN_P();
  	    goto unpack_integer;
  
  	  case 'n':
  	    signed_p = 0;
  	    integer_size = 2;
  	    bigendian_p = 1;
  	    goto unpack_integer;
  
  	  case 'N':
  	    signed_p = 0;
  	    integer_size = 4;
  	    bigendian_p = 1;
  	    goto unpack_integer;
  
  	  case 'v':
  	    signed_p = 0;
  	    integer_size = 2;
  	    bigendian_p = 0;
  	    goto unpack_integer;
  
  	  case 'V':
  	    signed_p = 0;
  	    integer_size = 4;
  	    bigendian_p = 0;
  	    goto unpack_integer;
  
  	  unpack_integer:
  	    if (explicit_endian) {
  		bigendian_p = explicit_endian == '>';
  	    }
              PACK_LENGTH_ADJUST_SIZE(integer_size);
              while (len-- > 0) {
                  int flags = bigendian_p ? INTEGER_PACK_BIG_ENDIAN : INTEGER_PACK_LITTLE_ENDIAN;
                  VALUE val;
                  if (signed_p)
                      flags |= INTEGER_PACK_2COMP;
                  val = rb_integer_unpack(s, integer_size, 1, 0, flags);
                  UNPACK_PUSH(val);
                  s += integer_size;
              }
              PACK_ITEM_ADJUST();
              break;
  
  	  case 'f':
  	  case 'F':
  	    PACK_LENGTH_ADJUST_SIZE(sizeof(float));
  	    while (len-- > 0) {
  		float tmp;
  		memcpy(&tmp, s, sizeof(float));
  		s += sizeof(float);
  		UNPACK_PUSH(DBL2NUM((double)tmp));
  	    }
  	    PACK_ITEM_ADJUST();
  	    break;
  
  	  case 'e':
  	    PACK_LENGTH_ADJUST_SIZE(sizeof(float));
  	    while (len-- > 0) {
  		FLOAT_CONVWITH(tmp);
  		memcpy(tmp.buf, s, sizeof(float));
  		s += sizeof(float);
  		VTOHF(tmp);
  		UNPACK_PUSH(DBL2NUM(tmp.f));
  	    }
  	    PACK_ITEM_ADJUST();
  	    break;
  
  	  case 'E':
  	    PACK_LENGTH_ADJUST_SIZE(sizeof(double));
  	    while (len-- > 0) {
  		DOUBLE_CONVWITH(tmp);
  		memcpy(tmp.buf, s, sizeof(double));
  		s += sizeof(double);
  		VTOHD(tmp);
  		UNPACK_PUSH(DBL2NUM(tmp.d));
  	    }
  	    PACK_ITEM_ADJUST();
  	    break;
  
  	  case 'D':
  	  case 'd':
  	    PACK_LENGTH_ADJUST_SIZE(sizeof(double));
  	    while (len-- > 0) {
  		double tmp;
  		memcpy(&tmp, s, sizeof(double));
  		s += sizeof(double);
  		UNPACK_PUSH(DBL2NUM(tmp));
  	    }
  	    PACK_ITEM_ADJUST();
  	    break;
  
  	  case 'g':
  	    PACK_LENGTH_ADJUST_SIZE(sizeof(float));
  	    while (len-- > 0) {
  		FLOAT_CONVWITH(tmp);
  		memcpy(tmp.buf, s, sizeof(float));
  		s += sizeof(float);
  		NTOHF(tmp);
  		UNPACK_PUSH(DBL2NUM(tmp.f));
  	    }
  	    PACK_ITEM_ADJUST();
  	    break;
  
  	  case 'G':
  	    PACK_LENGTH_ADJUST_SIZE(sizeof(double));
  	    while (len-- > 0) {
  		DOUBLE_CONVWITH(tmp);
  		memcpy(tmp.buf, s, sizeof(double));
  		s += sizeof(double);
  		NTOHD(tmp);
  		UNPACK_PUSH(DBL2NUM(tmp.d));
  	    }
  	    PACK_ITEM_ADJUST();
  	    break;
  
  	  case 'U':
  	    if (len > send - s) len = send - s;
  	    while (len > 0 && s < send) {
  		long alen = send - s;
  		unsigned long l;
  
  		l = utf8_to_uv(s, &alen);
  		s += alen; len--;
  		UNPACK_PUSH(ULONG2NUM(l));
  	    }
  	    break;
  
  	  case 'u':
  	    {
  		VALUE buf = infected_str_new(0, (send - s)*3/4, str);
  		char *ptr = RSTRING_PTR(buf);
  		long total = 0;
  
  		while (s < send && (unsigned char)*s > ' ' && (unsigned char)*s < 'a') {
  		    long a,b,c,d;
  		    char hunk[3];
  
  		    len = ((unsigned char)*s++ - ' ') & 077;
  
  		    total += len;
  		    if (total > RSTRING_LEN(buf)) {
  			len -= total - RSTRING_LEN(buf);
  			total = RSTRING_LEN(buf);
  		    }
  
  		    while (len > 0) {
  			long mlen = len > 3 ? 3 : len;
  
  			if (s < send && (unsigned char)*s >= ' ' && (unsigned char)*s < 'a')
  			    a = ((unsigned char)*s++ - ' ') & 077;
  			else
  			    a = 0;
  			if (s < send && (unsigned char)*s >= ' ' && (unsigned char)*s < 'a')
  			    b = ((unsigned char)*s++ - ' ') & 077;
  			else
  			    b = 0;
  			if (s < send && (unsigned char)*s >= ' ' && (unsigned char)*s < 'a')
  			    c = ((unsigned char)*s++ - ' ') & 077;
  			else
  			    c = 0;
  			if (s < send && (unsigned char)*s >= ' ' && (unsigned char)*s < 'a')
  			    d = ((unsigned char)*s++ - ' ') & 077;
  			else
  			    d = 0;
  			hunk[0] = (char)(a << 2 | b >> 4);
  			hunk[1] = (char)(b << 4 | c >> 2);
  			hunk[2] = (char)(c << 6 | d);
  			memcpy(ptr, hunk, mlen);
  			ptr += mlen;
  			len -= mlen;
  		    }
  		    if (s < send && (unsigned char)*s != '\r' && *s != '\n')
  			s++;	/* possible checksum byte */
  		    if (s < send && *s == '\r') s++;
  		    if (s < send && *s == '\n') s++;
  		}
  
  		rb_str_set_len(buf, total);
  		UNPACK_PUSH(buf);
  	    }
  	    break;
  
  	  case 'm':
  	    {
  		VALUE buf = infected_str_new(0, (send - s + 3)*3/4, str); /* +3 is for skipping paddings */
  		char *ptr = RSTRING_PTR(buf);
  		int a = -1,b = -1,c = 0,d = 0;
  		static signed char b64_xtable[256];
  
  		if (b64_xtable['/'] <= 0) {
  		    int i;
  
  		    for (i = 0; i < 256; i++) {
  			b64_xtable[i] = -1;
  		    }
  		    for (i = 0; i < 64; i++) {
  			b64_xtable[(unsigned char)b64_table[i]] = (char)i;
  		    }
  		}
  		if (len == 0) {
  		    while (s < send) {
  			a = b = c = d = -1;
  			a = b64_xtable[(unsigned char)*s++];
  			if (s >= send || a == -1) rb_raise(rb_eArgError, "invalid base64");
  			b = b64_xtable[(unsigned char)*s++];
  			if (s >= send || b == -1) rb_raise(rb_eArgError, "invalid base64");
  			if (*s == '=') {
  			    if (s + 2 == send && *(s + 1) == '=') break;
  			    rb_raise(rb_eArgError, "invalid base64");
  			}
  			c = b64_xtable[(unsigned char)*s++];
  			if (s >= send || c == -1) rb_raise(rb_eArgError, "invalid base64");
  			if (s + 1 == send && *s == '=') break;
  			d = b64_xtable[(unsigned char)*s++];
  			if (d == -1) rb_raise(rb_eArgError, "invalid base64");
  			*ptr++ = castchar(a << 2 | b >> 4);
  			*ptr++ = castchar(b << 4 | c >> 2);
  			*ptr++ = castchar(c << 6 | d);
  		    }
  		    if (c == -1) {
  			*ptr++ = castchar(a << 2 | b >> 4);
  			if (b & 0xf) rb_raise(rb_eArgError, "invalid base64");
  		    }
  		    else if (d == -1) {
  			*ptr++ = castchar(a << 2 | b >> 4);
  			*ptr++ = castchar(b << 4 | c >> 2);
  			if (c & 0x3) rb_raise(rb_eArgError, "invalid base64");
  		    }
  		}
  		else {
  		    while (s < send) {
  			a = b = c = d = -1;
  			while ((a = b64_xtable[(unsigned char)*s]) == -1 && s < send) {s++;}
  			if (s >= send) break;
  			s++;
  			while ((b = b64_xtable[(unsigned char)*s]) == -1 && s < send) {s++;}
  			if (s >= send) break;
  			s++;
  			while ((c = b64_xtable[(unsigned char)*s]) == -1 && s < send) {if (*s == '=') break; s++;}
  			if (*s == '=' || s >= send) break;
  			s++;
  			while ((d = b64_xtable[(unsigned char)*s]) == -1 && s < send) {if (*s == '=') break; s++;}
  			if (*s == '=' || s >= send) break;
  			s++;
  			*ptr++ = castchar(a << 2 | b >> 4);
  			*ptr++ = castchar(b << 4 | c >> 2);
  			*ptr++ = castchar(c << 6 | d);
  			a = -1;
  		    }
  		    if (a != -1 && b != -1) {
  			if (c == -1)
  			    *ptr++ = castchar(a << 2 | b >> 4);
  			else {
  			    *ptr++ = castchar(a << 2 | b >> 4);
  			    *ptr++ = castchar(b << 4 | c >> 2);
  			}
  		    }
  		}
  		rb_str_set_len(buf, ptr - RSTRING_PTR(buf));
  		UNPACK_PUSH(buf);
  	    }
  	    break;
  
  	  case 'M':
  	    {
  		VALUE buf = infected_str_new(0, send - s, str);
  		char *ptr = RSTRING_PTR(buf), *ss = s;
  		int c1, c2;
  
  		while (s < send) {
  		    if (*s == '=') {
  			if (++s == send) break;
  			if (s+1 < send && *s == '\r' && *(s+1) == '\n')
  			    s++;
  			if (*s != '\n') {
  			    if ((c1 = hex2num(*s)) == -1) break;
  			    if (++s == send) break;
  			    if ((c2 = hex2num(*s)) == -1) break;
  			    *ptr++ = castchar(c1 << 4 | c2);
  			}
  		    }
  		    else {
  			*ptr++ = *s;
  		    }
  		    s++;
  		    ss = s;
  		}
  		rb_str_set_len(buf, ptr - RSTRING_PTR(buf));
  		rb_str_buf_cat(buf, ss, send-ss);
  		ENCODING_CODERANGE_SET(buf, rb_ascii8bit_encindex(), ENC_CODERANGE_VALID);
  		UNPACK_PUSH(buf);
  	    }
  	    break;
  
  	  case '@':
  	    if (len > RSTRING_LEN(str))
  		rb_raise(rb_eArgError, "@ outside of string");
  	    s = RSTRING_PTR(str) + len;
  	    break;
  
  	  case 'X':
  	    if (len > s - RSTRING_PTR(str))
  		rb_raise(rb_eArgError, "X outside of string");
  	    s -= len;
  	    break;
  
  	  case 'x':
  	    if (len > send - s)
  		rb_raise(rb_eArgError, "x outside of string");
  	    s += len;
  	    break;
  
  	  case 'P':
  	    if (sizeof(char *) <= (size_t)(send - s)) {
  		VALUE tmp = Qnil;
  		char *t;
  
  		memcpy(&t, s, sizeof(char *));
  		s += sizeof(char *);
  
  		if (t) {
  		    VALUE a;
  		    const VALUE *p, *pend;
  
  		    if (!(a = str_associated(str))) {
  			rb_raise(rb_eArgError, "no associated pointer");
  		    }
  		    p = RARRAY_CONST_PTR(a);
  		    pend = p + RARRAY_LEN(a);
  		    while (p < pend) {
  			if (RB_TYPE_P(*p, T_STRING) && RSTRING_PTR(*p) == t) {
  			    if (len < RSTRING_LEN(*p)) {
  				tmp = rb_tainted_str_new(t, len);
  				str_associate(tmp, a);
  			    }
  			    else {
  				tmp = *p;
  			    }
  			    break;
  			}
  			p++;
  		    }
  		    if (p == pend) {
  			rb_raise(rb_eArgError, "non associated pointer");
  		    }
  		}
  		UNPACK_PUSH(tmp);
  	    }
  	    break;
  
  	  case 'p':
  	    if (len > (long)((send - s) / sizeof(char *)))
  		len = (send - s) / sizeof(char *);
  	    while (len-- > 0) {
  		if ((size_t)(send - s) < sizeof(char *))
  		    break;
  		else {
  		    VALUE tmp = Qnil;
  		    char *t;
  
  		    memcpy(&t, s, sizeof(char *));
  		    s += sizeof(char *);
  
  		    if (t) {
  			VALUE a;
  			const VALUE *p, *pend;
  
  			if (!(a = str_associated(str))) {
  			    rb_raise(rb_eArgError, "no associated pointer");
  			}
  			p = RARRAY_CONST_PTR(a);
  			pend = p + RARRAY_LEN(a);
  			while (p < pend) {
  			    if (RB_TYPE_P(*p, T_STRING) && RSTRING_PTR(*p) == t) {
  				tmp = *p;
  				break;
  			    }
  			    p++;
  			}
  			if (p == pend) {
  			    rb_raise(rb_eArgError, "non associated pointer");
  			}
  		    }
  		    UNPACK_PUSH(tmp);
  		}
  	    }
  	    break;
  
  	  case 'w':
  	    {
                  char *s0 = s;
                  while (len > 0 && s < send) {
                      if (*s & 0x80) {
                          s++;
                      }
                      else {
                          s++;
                          UNPACK_PUSH(rb_integer_unpack(s0, s-s0, 1, 1, INTEGER_PACK_BIG_ENDIAN));
                          len--;
                          s0 = s;
                      }
                  }
  	    }
  	    break;
  
  	  default:
  	    rb_warning("unknown unpack directive '%c' in '%s'",
  		type, RSTRING_PTR(fmt));
  	    break;
  	}
      }
  
      return ary;
  }
  
  int
  rb_uv_to_utf8(char buf[6], unsigned long uv)
  {
      if (uv <= 0x7f) {
  	buf[0] = (char)uv;
  	return 1;
      }
      if (uv <= 0x7ff) {
  	buf[0] = castchar(((uv>>6)&0xff)|0xc0);
  	buf[1] = castchar((uv&0x3f)|0x80);
  	return 2;
      }
      if (uv <= 0xffff) {
  	buf[0] = castchar(((uv>>12)&0xff)|0xe0);
  	buf[1] = castchar(((uv>>6)&0x3f)|0x80);
  	buf[2] = castchar((uv&0x3f)|0x80);
  	return 3;
      }
      if (uv <= 0x1fffff) {
  	buf[0] = castchar(((uv>>18)&0xff)|0xf0);
  	buf[1] = castchar(((uv>>12)&0x3f)|0x80);
  	buf[2] = castchar(((uv>>6)&0x3f)|0x80);
  	buf[3] = castchar((uv&0x3f)|0x80);
  	return 4;
      }
      if (uv <= 0x3ffffff) {
  	buf[0] = castchar(((uv>>24)&0xff)|0xf8);
  	buf[1] = castchar(((uv>>18)&0x3f)|0x80);
  	buf[2] = castchar(((uv>>12)&0x3f)|0x80);
  	buf[3] = castchar(((uv>>6)&0x3f)|0x80);
  	buf[4] = castchar((uv&0x3f)|0x80);
  	return 5;
      }
      if (uv <= 0x7fffffff) {
  	buf[0] = castchar(((uv>>30)&0xff)|0xfc);
  	buf[1] = castchar(((uv>>24)&0x3f)|0x80);
  	buf[2] = castchar(((uv>>18)&0x3f)|0x80);
  	buf[3] = castchar(((uv>>12)&0x3f)|0x80);
  	buf[4] = castchar(((uv>>6)&0x3f)|0x80);
  	buf[5] = castchar((uv&0x3f)|0x80);
  	return 6;
      }
      rb_raise(rb_eRangeError, "pack(U): value out of range");
  
      UNREACHABLE;
  }
  
  static const unsigned long utf8_limits[] = {
      0x0,			/* 1 */
      0x80,			/* 2 */
      0x800,			/* 3 */
      0x10000,			/* 4 */
      0x200000,			/* 5 */
      0x4000000,			/* 6 */
      0x80000000,			/* 7 */
  };
  
  static unsigned long
  utf8_to_uv(const char *p, long *lenp)
  {
      int c = *p++ & 0xff;
      unsigned long uv = c;
      long n;
  
      if (!(uv & 0x80)) {
  	*lenp = 1;
          return uv;
      }
      if (!(uv & 0x40)) {
  	*lenp = 1;
  	rb_raise(rb_eArgError, "malformed UTF-8 character");
      }
  
      if      (!(uv & 0x20)) { n = 2; uv &= 0x1f; }
      else if (!(uv & 0x10)) { n = 3; uv &= 0x0f; }
      else if (!(uv & 0x08)) { n = 4; uv &= 0x07; }
      else if (!(uv & 0x04)) { n = 5; uv &= 0x03; }
      else if (!(uv & 0x02)) { n = 6; uv &= 0x01; }
      else {
  	*lenp = 1;
  	rb_raise(rb_eArgError, "malformed UTF-8 character");
      }
      if (n > *lenp) {
  	rb_raise(rb_eArgError, "malformed UTF-8 character (expected %ld bytes, given %ld bytes)",
  		 n, *lenp);
      }
      *lenp = n--;
      if (n != 0) {
  	while (n--) {
  	    c = *p++ & 0xff;
  	    if ((c & 0xc0) != 0x80) {
  		*lenp -= n + 1;
  		rb_raise(rb_eArgError, "malformed UTF-8 character");
  	    }
  	    else {
  		c &= 0x3f;
  		uv = uv << 6 | c;
  	    }
  	}
      }
      n = *lenp - 1;
      if (uv < utf8_limits[n]) {
  	rb_raise(rb_eArgError, "redundant UTF-8 sequence");
      }
      return uv;
  }
  
  void
  Init_pack(void)
  {
      rb_define_method(rb_cArray, "pack", pack_pack, 1);
      rb_define_method(rb_cString, "unpack", pack_unpack, 1);
  
      id_associated = rb_make_internal_id();
  }
  