* tags.h, deprecated.h (SCM_EQ_P): Deprecated by moving it into

[bpt/guile.git] / srfi / srfi-13.c

/* srfi-13.c --- SRFI-13 procedures for Guile
 *
 * Copyright (C) 2001, 2004 Free Software Foundation, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


#include <string.h>
#include <ctype.h>

#include <libguile.h>

#include "srfi-13.h"
#include "srfi-14.h"

SCM_DEFINE (scm_string_any, "string-any", 2, 2, 0,
            (SCM pred, SCM s, SCM start, SCM end),
            "Check if the predicate @var{pred} is true for any character in\n"
            "the string @var{s}, proceeding from left (index @var{start}) to\n"
            "right (index @var{end}).  If @code{string-any} returns true,\n"
            "the returned true value is the one produced by the first\n"
            "successful application of @var{pred}.")
#define FUNC_NAME s_scm_string_any
{
  char * cstr;
  int cstart, cend;
  SCM res;

  SCM_VALIDATE_PROC (1, pred);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  cstr += cstart;
  while (cstart < cend)
    {
      res = scm_call_1 (pred, SCM_MAKE_CHAR (*cstr));
      if (scm_is_true (res))
        return res;
      cstr++;
      cstart++;
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_every, "string-every", 2, 2, 0,
            (SCM pred, SCM s, SCM start, SCM end),
            "Check if the predicate @var{pred} is true for every character\n"
            "in the string @var{s}, proceeding from left (index @var{start})\n"
            "to right (index @var{end}).  If @code{string-every} returns\n"
            "true, the returned true value is the one produced by the final\n"
            "application of @var{pred} to the last character of @var{s}.")
#define FUNC_NAME s_scm_string_every
{
  char * cstr;
  int cstart, cend;
  SCM res;

  SCM_VALIDATE_PROC (1, pred);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  res = SCM_BOOL_F;
  cstr += cstart;
  while (cstart < cend)
    {
      res = scm_call_1 (pred, SCM_MAKE_CHAR (*cstr));
      if (scm_is_false (res))
        return res;
      cstr++;
      cstart++;
    }
  return res;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_tabulate, "string-tabulate", 2, 0, 0,
            (SCM proc, SCM len),
            "@var{proc} is an integer->char procedure.  Construct a string\n"
            "of size @var{len} by applying @var{proc} to each index to\n"
            "produce the corresponding string element.  The order in which\n"
            "@var{proc} is applied to the indices is not specified.")
#define FUNC_NAME s_scm_string_tabulate
{
  size_t clen, i;
  SCM res;
  SCM ch;
  char * p;

  SCM_VALIDATE_PROC (1, proc);
  clen = scm_to_size_t (len);
  SCM_ASSERT_RANGE (2, len, clen >= 0);

  res = scm_allocate_string (clen);
  p = SCM_STRING_CHARS (res);
  i = 0;
  while (i < clen)
    {
      ch = scm_call_1 (proc, scm_from_int (i));
      if (!SCM_CHARP (ch))
        SCM_MISC_ERROR ("procedure ~S returned non-char", scm_list_1 (proc));
      *p++ = SCM_CHAR (ch);
      i++;
    }
  return res;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_to_listS, "string->list", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Convert the string @var{str} into a list of characters.")
#define FUNC_NAME s_scm_string_to_listS
{
  char * cstr;
  int cstart, cend;
  SCM result = SCM_EOL;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  while (cstart < cend)
    {
      cend--;
      result = scm_cons (SCM_MAKE_CHAR (cstr[cend]), result);
    }
  return result;
}
#undef FUNC_NAME

SCM_DEFINE (scm_reverse_list_to_string, "reverse-list->string", 1, 0, 0,
            (SCM chrs),
            "An efficient implementation of @code{(compose string->list\n"
            "reverse)}:\n"
            "\n"
            "@smalllisp\n"
            "(reverse-list->string '(#\a #\B #\c)) @result{} \"cBa\"\n"
            "@end smalllisp")
#define FUNC_NAME s_scm_reverse_list_to_string
{
  SCM result;
  long i = scm_ilength (chrs);

  if (i < 0)
    SCM_WRONG_TYPE_ARG (1, chrs);
  result = scm_allocate_string (i);

  {
    unsigned char *data = SCM_STRING_UCHARS (result) + i;

    while (!SCM_NULLP (chrs))
      {
        SCM elt = SCM_CAR (chrs);

        SCM_VALIDATE_CHAR (SCM_ARGn, elt);
        data--;
        *data = SCM_CHAR (elt);
        chrs = SCM_CDR (chrs);
      }
  }
  return result;
}
#undef FUNC_NAME


SCM_SYMBOL (scm_sym_infix, "infix");
SCM_SYMBOL (scm_sym_strict_infix, "strict-infix");
SCM_SYMBOL (scm_sym_suffix, "suffix");
SCM_SYMBOL (scm_sym_prefix, "prefix");

SCM_DEFINE (scm_string_join, "string-join", 1, 2, 0,
            (SCM ls, SCM delimiter, SCM grammar),
            "Append the string in the string list @var{ls}, using the string\n"
            "@var{delim} as a delimiter between the elements of @var{ls}.\n"
            "@var{grammar} is a symbol which specifies how the delimiter is\n"
            "placed between the strings, and defaults to the symbol\n"
            "@code{infix}.\n"
            "\n"
            "@table @code\n"
            "@item infix\n"
            "Insert the separator between list elements.  An empty string\n"
            "will produce an empty list.\n"
            "@item string-infix\n"
            "Like @code{infix}, but will raise an error if given the empty\n"
            "list.\n"
            "@item suffix\n"
            "Insert the separator after every list element.\n"
            "@item prefix\n"
            "Insert the separator before each list element.\n"
            "@end table")
#define FUNC_NAME s_scm_string_join
{
#define GRAM_INFIX        0
#define GRAM_STRICT_INFIX 1
#define GRAM_SUFFIX       2
#define GRAM_PREFIX       3
  SCM tmp;
  SCM result;
  int gram = GRAM_INFIX;
  int del_len = 0, extra_len = 0;
  int len = 0;
  char * p;
  long strings = scm_ilength (ls);

  /* Validate the string list.  */
  if (strings < 0)
    SCM_WRONG_TYPE_ARG (1, ls);

  /* Validate the delimiter and record its length.  */
  if (SCM_UNBNDP (delimiter))
    {
      delimiter = scm_makfrom0str (" ");
      del_len = 1;
    }
  else
    {
      SCM_VALIDATE_STRING (2, delimiter);
      del_len = SCM_STRING_LENGTH (delimiter);
    }

  /* Validate the grammar symbol and remember the grammar.  */
  if (SCM_UNBNDP (grammar))
    gram = GRAM_INFIX;
  else if (scm_is_eq (grammar, scm_sym_infix))
    gram = GRAM_INFIX;
  else if (scm_is_eq (grammar, scm_sym_strict_infix))
    gram = GRAM_STRICT_INFIX;
  else if (scm_is_eq (grammar, scm_sym_suffix))
    gram = GRAM_SUFFIX;
  else if (scm_is_eq (grammar, scm_sym_prefix))
    gram = GRAM_PREFIX;
  else
    SCM_WRONG_TYPE_ARG (3, grammar);

  /* Check grammar constraints and calculate the space required for
     the delimiter(s).  */
  switch (gram)
    {
    case GRAM_INFIX:
      if (!SCM_NULLP (ls))
        extra_len = (strings > 0) ? ((strings - 1) * del_len) : 0;
      break;
    case GRAM_STRICT_INFIX:
      if (strings == 0)
        SCM_MISC_ERROR ("strict-infix grammar requires non-empty list",
                        SCM_EOL);
      extra_len = (strings - 1) * del_len;
      break;
    default:
      extra_len = strings * del_len;
      break;
    }

  tmp = ls;
  while (SCM_CONSP (tmp))
    {
      SCM elt = SCM_CAR (tmp);
      SCM_VALIDATE_STRING (1, elt);
      len += SCM_STRING_LENGTH (elt);
      tmp = SCM_CDR (tmp);
    }

  result = scm_allocate_string (len + extra_len);
  p = SCM_STRING_CHARS (result);

  tmp = ls;
  switch (gram)
    {
    case GRAM_INFIX:
    case GRAM_STRICT_INFIX:
      while (!SCM_NULLP (tmp))
        {
          SCM elt = SCM_CAR (tmp);
          memmove (p, SCM_STRING_CHARS (elt),
                   SCM_STRING_LENGTH (elt) * sizeof (char));
          p += SCM_STRING_LENGTH (elt);
          if (!SCM_NULLP (SCM_CDR (tmp)) && del_len > 0)
            {
              memmove (p, SCM_STRING_CHARS (delimiter),
                       SCM_STRING_LENGTH (delimiter) * sizeof (char));
              p += del_len;
            }
          tmp = SCM_CDR (tmp);
        }
      break;
    case GRAM_SUFFIX:
      while (!SCM_NULLP (tmp))
        {
          SCM elt = SCM_CAR (tmp);
          memmove (p, SCM_STRING_CHARS (elt),
                   SCM_STRING_LENGTH (elt) * sizeof (char));
          p += SCM_STRING_LENGTH (elt);
          if (del_len > 0)
            {
              memmove (p, SCM_STRING_CHARS (delimiter),
                       SCM_STRING_LENGTH (delimiter) * sizeof (char));
              p += del_len;
            }
          tmp = SCM_CDR (tmp);
        }
      break;
    case GRAM_PREFIX:
      while (!SCM_NULLP (tmp))
        {
          SCM elt = SCM_CAR (tmp);
          if (del_len > 0)
            {
              memmove (p, SCM_STRING_CHARS (delimiter),
                       SCM_STRING_LENGTH (delimiter) * sizeof (char));
              p += del_len;
            }
          memmove (p, SCM_STRING_CHARS (elt),
                   SCM_STRING_LENGTH (elt) * sizeof (char));
          p += SCM_STRING_LENGTH (elt);
          tmp = SCM_CDR (tmp);
        }
      break;
    }
  return result;
#undef GRAM_INFIX
#undef GRAM_STRICT_INFIX
#undef GRAM_SUFFIX
#undef GRAM_PREFIX
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_copyS, "string-copy", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Return a freshly allocated copy of the string @var{str}.  If\n"
            "given, @var{start} and @var{end} delimit the portion of\n"
            "@var{str} which is copied.")
#define FUNC_NAME s_scm_string_copyS
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return scm_mem2string (cstr + cstart, cend - cstart);

}
#undef FUNC_NAME


SCM_DEFINE (scm_substring_shared, "substring/shared", 2, 1, 0,
            (SCM str, SCM start, SCM end),
            "Like @code{substring}, but the result may share memory with the\n"
            "argument @var{str}.")
#define FUNC_NAME s_scm_substring_shared
{
  size_t s, e;
  SCM_VALIDATE_STRING (1, str);
  s = scm_to_size_t (start);
  if (SCM_UNBNDP (end))
    e = SCM_STRING_LENGTH (str);
  else
    e = scm_to_size_t (end);
  if (s == 0 && e == SCM_STRING_LENGTH (str))
    return str;
  else
    return scm_substring (str, start, end);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_copy_x, "string-copy!", 3, 2, 0,
            (SCM target, SCM tstart, SCM s, SCM start, SCM end),
            "Copy the sequence of characters from index range [@var{start},\n"
            "@var{end}) in string @var{s} to string @var{target}, beginning\n"
            "at index @var{tstart}.  The characters are copied left-to-right\n"
            "or right-to-left as needed -- the copy is guaranteed to work,\n"
            "even if @var{target} and @var{s} are the same string.  It is an\n"
            "error if the copy operation runs off the end of the target\n"
            "string.")
#define FUNC_NAME s_scm_string_copy_x
{
  char * cstr, * ctarget;
  int cstart, cend, ctstart, dummy;
  int len;
  SCM sdummy = SCM_UNDEFINED;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, target, ctarget,
                                    2, tstart, ctstart,
                                    2, sdummy, dummy);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (3, s, cstr,
                                    4, start, cstart,
                                    5, end, cend);
  len = cend - cstart;
  SCM_ASSERT_RANGE (3, s, len <= SCM_STRING_LENGTH (target) - ctstart);

  memmove (SCM_STRING_CHARS (target) + ctstart,
           SCM_STRING_CHARS (s) + cstart,
           len * sizeof (char));
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_take, "string-take", 2, 0, 0,
            (SCM s, SCM n),
            "Return the @var{n} first characters of @var{s}.")
#define FUNC_NAME s_scm_string_take
{
  char * cstr;
  size_t cn;

  SCM_VALIDATE_STRING_COPY (1, s, cstr);
  cn = scm_to_unsigned_integer (n, 0, SCM_STRING_LENGTH (s));

  return scm_mem2string (cstr, cn);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_drop, "string-drop", 2, 0, 0,
            (SCM s, SCM n),
            "Return all but the first @var{n} characters of @var{s}.")
#define FUNC_NAME s_scm_string_drop
{
  char * cstr;
  size_t cn;

  SCM_VALIDATE_STRING_COPY (1, s, cstr);
  cn = scm_to_unsigned_integer (n, 0, SCM_STRING_LENGTH (s));

  return scm_mem2string (cstr + cn, SCM_STRING_LENGTH (s) - cn);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_take_right, "string-take-right", 2, 0, 0,
            (SCM s, SCM n),
            "Return the @var{n} last characters of @var{s}.")
#define FUNC_NAME s_scm_string_take_right
{
  char * cstr;
  size_t cn;

  SCM_VALIDATE_STRING_COPY (1, s, cstr);
  cn = scm_to_unsigned_integer (n, 0, SCM_STRING_LENGTH (s));

  return scm_mem2string (cstr + SCM_STRING_LENGTH (s) - cn, cn);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_drop_right, "string-drop-right", 2, 0, 0,
            (SCM s, SCM n),
            "Return all but the last @var{n} characters of @var{s}.")
#define FUNC_NAME s_scm_string_drop_right
{
  char * cstr;
  size_t cn;

  SCM_VALIDATE_STRING_COPY (1, s, cstr);
  cn = scm_to_unsigned_integer (n, 0, SCM_STRING_LENGTH (s));

  return scm_mem2string (cstr, SCM_STRING_LENGTH (s) - cn);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_pad, "string-pad", 2, 3, 0,
            (SCM s, SCM len, SCM chr, SCM start, SCM end),
            "Take that characters from @var{start} to @var{end} from the\n"
            "string @var{s} and return a new string, right-padded by the\n"
            "character @var{chr} to length @var{len}.  If the resulting\n"
            "string is longer than @var{len}, it is truncated on the right.")
#define FUNC_NAME s_scm_string_pad
{
  char cchr;
  char * cstr;
  size_t cstart, cend, clen;
  SCM result;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    4, start, cstart,
                                    5, end, cend);
  clen = scm_to_size_t (len);

  if (SCM_UNBNDP (chr))
    cchr = ' ';
  else
    {
      SCM_VALIDATE_CHAR (3, chr);
      cchr = SCM_CHAR (chr);
    }
  result = scm_allocate_string (clen);
  if (clen < (cend - cstart))
    memmove (SCM_STRING_CHARS (result),
             cstr + cend - clen,
             clen * sizeof (char));
  else
    {
      memset (SCM_STRING_CHARS (result), cchr,
              (clen - (cend - cstart)) * sizeof (char));
      memmove (SCM_STRING_CHARS (result) + (clen - (cend - cstart)),
               cstr + cstart,
               (cend - cstart) * sizeof (char));
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_pad_right, "string-pad-right", 2, 3, 0,
            (SCM s, SCM len, SCM chr, SCM start, SCM end),
            "Take that characters from @var{start} to @var{end} from the\n"
            "string @var{s} and return a new string, left-padded by the\n"
            "character @var{chr} to length @var{len}.  If the resulting\n"
            "string is longer than @var{len}, it is truncated on the left.")
#define FUNC_NAME s_scm_string_pad_right
{
  char cchr;
  char * cstr;
  size_t cstart, cend, clen;
  SCM result;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    4, start, cstart,
                                    5, end, cend);
  clen = scm_to_size_t (len);

  if (SCM_UNBNDP (chr))
    cchr = ' ';
  else
    {
      SCM_VALIDATE_CHAR (3, chr);
      cchr = SCM_CHAR (chr);
    }
  result = scm_allocate_string (clen);
  if (clen < (cend - cstart))
    memmove (SCM_STRING_CHARS (result), cstr + cstart, clen * sizeof (char));
  else
    {
      memset (SCM_STRING_CHARS (result) + (cend - cstart),
              cchr, (clen - (cend - cstart)) * sizeof (char));
      memmove (SCM_STRING_CHARS (result), cstr + cstart,
               (cend - cstart) * sizeof (char));
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_trim, "string-trim", 1, 3, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Trim @var{s} by skipping over all characters on the left\n"
            "that satisfy the parameter @var{char_pred}:\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "if it is the character @var{ch}, characters equal to\n"
            "@var{ch} are trimmed,\n"
            "\n"
            "@item\n"
            "if it is a procedure @var{pred} characters that\n"
            "satisfy @var{pred} are trimmed,\n"
            "\n"
            "@item\n"
            "if it is a character set, characters in that set are trimmed.\n"
            "@end itemize\n"
            "\n"
            "If called without a @var{char_pred} argument, all whitespace is\n"
            "trimmed.")
#define FUNC_NAME s_scm_string_trim
{
  char * cstr;
  size_t cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_UNBNDP (char_pred))
    {
      while (cstart < cend)
        {
          if (!isspace((int) (unsigned char) cstr[cstart]))
            break;
          cstart++;
        }
    }
  else if (SCM_CHARP (char_pred))
    {
      char chr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          if (chr != cstr[cstart])
            break;
          cstart++;
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          if (!SCM_CHARSET_GET (char_pred, cstr[cstart]))
            break;
          cstart++;
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;

          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cstart]));
          if (scm_is_false (res))
            break;
          cstart++;
        }
    }
  return scm_mem2string (cstr + cstart, cend - cstart);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_trim_right, "string-trim-right", 1, 3, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Trim @var{s} by skipping over all characters on the rightt\n"
            "that satisfy the parameter @var{char_pred}:\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "if it is the character @var{ch}, characters equal to @var{ch}\n"
            "are trimmed,\n"
            "\n"
            "@item\n"
            "if it is a procedure @var{pred} characters that satisfy\n"
            "@var{pred} are trimmed,\n"
            "\n"
            "@item\n"
            "if it is a character sets, all characters in that set are\n"
            "trimmed.\n"
            "@end itemize\n"
            "\n"
            "If called without a @var{char_pred} argument, all whitespace is\n"
            "trimmed.")
#define FUNC_NAME s_scm_string_trim_right
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_UNBNDP (char_pred))
    {
      while (cstart < cend)
        {
          if (!isspace((int) (unsigned char) cstr[cend - 1]))
            break;
          cend--;
        }
    }
  else if (SCM_CHARP (char_pred))
    {
      char chr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          if (chr != cstr[cend - 1])
            break;
          cend--;
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          if (!SCM_CHARSET_GET (char_pred, cstr[cend - 1]))
            break;
          cend--;
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;

          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cend - 1]));
          if (scm_is_false (res))
            break;
          cend--;
        }
    }
  return scm_mem2string (cstr + cstart, cend - cstart);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_trim_both, "string-trim-both", 1, 3, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Trim @var{s} by skipping over all characters on both sides of\n"
            "the string that satisfy the parameter @var{char_pred}:\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "if it is the character @var{ch}, characters equal to @var{ch}\n"
            "are trimmed,\n"
            "\n"
            "@item\n"
            "if it is a procedure @var{pred} characters that satisfy\n"
            "@var{pred} are trimmed,\n"
            "\n"
            "@item\n"
            "if it is a character set, the characters in the set are\n"
            "trimmed.\n"
            "@end itemize\n"
            "\n"
            "If called without a @var{char_pred} argument, all whitespace is\n"
            "trimmed.")
#define FUNC_NAME s_scm_string_trim_both
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_UNBNDP (char_pred))
    {
      while (cstart < cend)
        {
          if (!isspace((int) (unsigned char) cstr[cstart]))
            break;
          cstart++;
        }
      while (cstart < cend)
        {
          if (!isspace((int) (unsigned char) cstr[cend - 1]))
            break;
          cend--;
        }
    }
  else if (SCM_CHARP (char_pred))
    {
      char chr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          if (chr != cstr[cstart])
            break;
          cstart++;
        }
      while (cstart < cend)
        {
          if (chr != cstr[cend - 1])
            break;
          cend--;
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          if (!SCM_CHARSET_GET (char_pred, cstr[cstart]))
            break;
          cstart++;
        }
      while (cstart < cend)
        {
          if (!SCM_CHARSET_GET (char_pred, cstr[cend - 1]))
            break;
          cend--;
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;

          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cstart]));
          if (scm_is_false (res))
            break;
          cstart++;
        }
      while (cstart < cend)
        {
          SCM res;

          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cend - 1]));
          if (scm_is_false (res))
            break;
          cend--;
        }
    }
  return scm_mem2string (cstr + cstart, cend - cstart);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_fill_xS, "string-fill!", 2, 2, 0,
            (SCM str, SCM chr, SCM start, SCM end),
            "Stores @var{chr} in every element of the given @var{str} and\n"
            "returns an unspecified value.")
#define FUNC_NAME s_scm_string_fill_xS
{
  char * cstr;
  int cstart, cend;
  int c;
  long k;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  SCM_VALIDATE_CHAR_COPY (2, chr, c);
  for (k = cstart; k < cend; k++)
    cstr[k] = c;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_compare, "string-compare", 5, 4, 0,
            (SCM s1, SCM s2, SCM proc_lt, SCM proc_eq, SCM proc_gt, SCM start1, SCM end1, SCM start2, SCM end2),
            "Apply @var{proc_lt}, @var{proc_eq}, @var{proc_gt} to the\n"
            "mismatch index, depending upon whether @var{s1} is less than,\n"
            "equal to, or greater than @var{s2}.  The mismatch index is the\n"
            "largest index @var{i} such that for every 0 <= @var{j} <\n"
            "@var{i}, @var{s1}[@var{j}] = @var{s2}[@var{j}] -- that is,\n"
            "@var{i} is the first position that does not match.")
#define FUNC_NAME s_scm_string_compare
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    6, start1, cstart1,
                                    7, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    8, start2, cstart2,
                                    9, end2, cend2);
  SCM_VALIDATE_PROC (3, proc_lt);
  SCM_VALIDATE_PROC (4, proc_eq);
  SCM_VALIDATE_PROC (5, proc_gt);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return scm_call_1 (proc_lt, SCM_I_MAKINUM (cstart1));
      else if (cstr1[cstart1] > cstr2[cstart2])
        return scm_call_1 (proc_gt, SCM_I_MAKINUM (cstart1));
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return scm_call_1 (proc_gt, SCM_I_MAKINUM (cstart1));
  else if (cstart2 < cend2)
    return scm_call_1 (proc_lt, SCM_I_MAKINUM (cstart1));
  else
    return scm_call_1 (proc_eq, SCM_I_MAKINUM (cstart1));
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_compare_ci, "string-compare-ci", 5, 4, 0,
            (SCM s1, SCM s2, SCM proc_lt, SCM proc_eq, SCM proc_gt, SCM start1, SCM end1, SCM start2, SCM end2),
            "Apply @var{proc_lt}, @var{proc_eq}, @var{proc_gt} to the\n"
            "mismatch index, depending upon whether @var{s1} is less than,\n"
            "equal to, or greater than @var{s2}.  The mismatch index is the\n"
            "largest index @var{i} such that for every 0 <= @var{j} <\n"
            "@var{i}, @var{s1}[@var{j}] = @var{s2}[@var{j}] -- that is,\n"
            "@var{i} is the first position that does not match.  The\n"
            "character comparison is done case-insensitively.")
#define FUNC_NAME s_scm_string_compare_ci
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    6, start1, cstart1,
                                    7, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    8, start2, cstart2,
                                    9, end2, cend2);
  SCM_VALIDATE_PROC (3, proc_lt);
  SCM_VALIDATE_PROC (4, proc_eq);
  SCM_VALIDATE_PROC (5, proc_gt);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return scm_call_1 (proc_lt, SCM_I_MAKINUM (cstart1));
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return scm_call_1 (proc_gt, SCM_I_MAKINUM (cstart1));
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return scm_call_1 (proc_gt, SCM_I_MAKINUM (cstart1));
  else if (cstart2 < cend2)
    return scm_call_1 (proc_lt, SCM_I_MAKINUM (cstart1));
  else
    return scm_call_1 (proc_eq, SCM_I_MAKINUM (cstart1));
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_eq, "string=", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} and @var{s2} are not equal, a true\n"
            "value otherwise.")
#define FUNC_NAME s_scm_string_eq
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return SCM_BOOL_F;
      else if (cstr1[cstart1] > cstr2[cstart2])
        return SCM_BOOL_F;
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_BOOL_F;
  else if (cstart2 < cend2)
    return SCM_BOOL_F;
  else
    return SCM_I_MAKINUM (cstart1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_neq, "string<>", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} and @var{s2} are equal, a true\n"
            "value otherwise.")
#define FUNC_NAME s_scm_string_neq
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return SCM_I_MAKINUM (cstart1);
      else if (cstr1[cstart1] > cstr2[cstart2])
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_I_MAKINUM (cstart1);
  else if (cstart2 < cend2)
    return SCM_I_MAKINUM (cstart1);
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_lt, "string<", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is greater or equal to @var{s2}, a\n"
            "true value otherwise.")
#define FUNC_NAME s_scm_string_lt
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return SCM_I_MAKINUM (cstart1);
      else if (cstr1[cstart1] > cstr2[cstart2])
        return SCM_BOOL_F;
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_BOOL_F;
  else if (cstart2 < cend2)
    return SCM_I_MAKINUM (cstart1);
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_gt, "string>", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is less or equal to @var{s2}, a\n"
            "true value otherwise.")
#define FUNC_NAME s_scm_string_gt
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return SCM_BOOL_F;
      else if (cstr1[cstart1] > cstr2[cstart2])
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_I_MAKINUM (cstart1);
  else if (cstart2 < cend2)
    return SCM_BOOL_F;
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_le, "string<=", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is greater to @var{s2}, a true\n"
            "value otherwise.")
#define FUNC_NAME s_scm_string_le
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return SCM_I_MAKINUM (cstart1);
      else if (cstr1[cstart1] > cstr2[cstart2])
        return SCM_BOOL_F;
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_BOOL_F;
  else if (cstart2 < cend2)
    return SCM_I_MAKINUM (cstart1);
  else
    return SCM_I_MAKINUM (cstart1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ge, "string>=", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is less to @var{s2}, a true value\n"
            "otherwise.")
#define FUNC_NAME s_scm_string_ge
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] < cstr2[cstart2])
        return SCM_BOOL_F;
      else if (cstr1[cstart1] > cstr2[cstart2])
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_I_MAKINUM (cstart1);
  else if (cstart2 < cend2)
    return SCM_BOOL_F;
  else
    return SCM_I_MAKINUM (cstart1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ci_eq, "string-ci=", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} and @var{s2} are not equal, a true\n"
            "value otherwise.  The character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_ci_eq
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return SCM_BOOL_F;
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return SCM_BOOL_F;
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_BOOL_F;
  else if (cstart2 < cend2)
    return SCM_BOOL_F;
  else
    return SCM_I_MAKINUM (cstart1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ci_neq, "string-ci<>", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} and @var{s2} are equal, a true\n"
            "value otherwise.  The character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_ci_neq
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (cstart1);
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_I_MAKINUM (cstart1);
  else if (cstart2 < cend2)
    return SCM_I_MAKINUM (cstart1);
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ci_lt, "string-ci<", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is greater or equal to @var{s2}, a\n"
            "true value otherwise.  The character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_ci_lt
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (cstart1);
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return SCM_BOOL_F;
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_BOOL_F;
  else if (cstart2 < cend2)
    return SCM_I_MAKINUM (cstart1);
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ci_gt, "string-ci>", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is less or equal to @var{s2}, a\n"
            "true value otherwise.  The character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_ci_gt
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return SCM_BOOL_F;
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_I_MAKINUM (cstart1);
  else if (cstart2 < cend2)
    return SCM_BOOL_F;
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ci_le, "string-ci<=", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is greater to @var{s2}, a true\n"
            "value otherwise.  The character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_ci_le
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (cstart1);
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return SCM_BOOL_F;
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_BOOL_F;
  else if (cstart2 < cend2)
    return SCM_I_MAKINUM (cstart1);
  else
    return SCM_I_MAKINUM (cstart1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_ci_ge, "string-ci>=", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return @code{#f} if @var{s1} is less to @var{s2}, a true value\n"
            "otherwise.  The character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_ci_ge
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);

  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) < scm_c_downcase (cstr2[cstart2]))
        return SCM_BOOL_F;
      else if (scm_c_downcase (cstr1[cstart1]) > scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
      cstart2++;
    }
  if (cstart1 < cend1)
    return SCM_I_MAKINUM (cstart1);
  else if (cstart2 < cend2)
    return SCM_BOOL_F;
  else
    return SCM_I_MAKINUM (cstart1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_prefix_length, "string-prefix-length", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return the length of the longest common prefix of the two\n"
            "strings.")
#define FUNC_NAME s_scm_string_prefix_length
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] != cstr2[cstart2])
        return SCM_I_MAKINUM (len);
      len++;
      cstart1++;
      cstart2++;
    }
  return SCM_I_MAKINUM (len);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_prefix_length_ci, "string-prefix-length-ci", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return the length of the longest common prefix of the two\n"
            "strings, ignoring character case.")
#define FUNC_NAME s_scm_string_prefix_length_ci
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) != scm_c_downcase (cstr2[cstart2]))
        return SCM_I_MAKINUM (len);
      len++;
      cstart1++;
      cstart2++;
    }
  return SCM_I_MAKINUM (len);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_suffix_length, "string-suffix-length", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return the length of the longest common suffix of the two\n"
            "strings.")
#define FUNC_NAME s_scm_string_suffix_length
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      cend1--;
      cend2--;
      if (cstr1[cend1] != cstr2[cend2])
        return SCM_I_MAKINUM (len);
      len++;
    }
  return SCM_I_MAKINUM (len);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_suffix_length_ci, "string-suffix-length-ci", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return the length of the longest common suffix of the two\n"
            "strings, ignoring character case.")
#define FUNC_NAME s_scm_string_suffix_length_ci
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      cend1--;
      cend2--;
      if (scm_c_downcase (cstr1[cend1]) != scm_c_downcase (cstr2[cend2]))
        return SCM_I_MAKINUM (len);
      len++;
    }
  return SCM_I_MAKINUM (len);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_prefix_p, "string-prefix?", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Is @var{s1} a prefix of @var{s2}?")
#define FUNC_NAME s_scm_string_prefix_p
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0, len1;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  len1 = cend1 - cstart1;
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (cstr1[cstart1] != cstr2[cstart2])
        return scm_from_bool (len == len1);
      len++;
      cstart1++;
      cstart2++;
    }
  return scm_from_bool (len == len1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_prefix_ci_p, "string-prefix-ci?", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Is @var{s1} a prefix of @var{s2}, ignoring character case?")
#define FUNC_NAME s_scm_string_prefix_ci_p
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0, len1;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  len1 = cend1 - cstart1;
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      if (scm_c_downcase (cstr1[cstart1]) != scm_c_downcase (cstr2[cstart2]))
        return scm_from_bool (len == len1);
      len++;
      cstart1++;
      cstart2++;
    }
  return scm_from_bool (len == len1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_suffix_p, "string-suffix?", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Is @var{s1} a suffix of @var{s2}?")
#define FUNC_NAME s_scm_string_suffix_p
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0, len1;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  len1 = cend1 - cstart1;
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      cend1--;
      cend2--;
      if (cstr1[cend1] != cstr2[cend2])
        return scm_from_bool (len == len1);
      len++;
    }
  return scm_from_bool (len == len1);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_suffix_ci_p, "string-suffix-ci?", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Is @var{s1} a suffix of @var{s2}, ignoring character case?")
#define FUNC_NAME s_scm_string_suffix_ci_p
{
  char * cstr1, * cstr2;
  int cstart1, cend1, cstart2, cend2;
  int len = 0, len1;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  len1 = cend1 - cstart1;
  while (cstart1 < cend1 && cstart2 < cend2)
    {
      cend1--;
      cend2--;
      if (scm_c_downcase (cstr1[cend1]) != scm_c_downcase (cstr2[cend2]))
        return scm_from_bool (len == len1);
      len++;
    }
  return scm_from_bool (len == len1);
}
#undef FUNC_NAME


/* FIXME::martin: The `S' is to avoid a name clash with the procedure
   in the core, which does not accept a predicate. */
SCM_DEFINE (scm_string_indexS, "string-index", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Search through the string @var{s} from left to right, returning\n"
            "the index of the first occurence of a character which\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "equals @var{char_pred}, if it is character,\n"
            "\n"
            "@item\n"
            "satisifies the predicate @var{char_pred}, if it is a procedure,\n"
            "\n"
            "@item\n"
            "is in the set @var{char_pred}, if it is a character set.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_indexS
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      char cchr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          if (cchr == cstr[cstart])
            return SCM_I_MAKINUM (cstart);
          cstart++;
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          if (SCM_CHARSET_GET (char_pred, cstr[cstart]))
            return SCM_I_MAKINUM (cstart);
          cstart++;
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cstart]));
          if (scm_is_true (res))
            return SCM_I_MAKINUM (cstart);
          cstart++;
        }
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_index_right, "string-index-right", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Search through the string @var{s} from right to left, returning\n"
            "the index of the last occurence of a character which\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "equals @var{char_pred}, if it is character,\n"
            "\n"
            "@item\n"
            "satisifies the predicate @var{char_pred}, if it is a procedure,\n"
            "\n"
            "@item\n"
            "is in the set if @var{char_pred} is a character set.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_index_right
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      char cchr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          cend--;
          if (cchr == cstr[cend])
            return SCM_I_MAKINUM (cend);
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          cend--;
          if (SCM_CHARSET_GET (char_pred, cstr[cend]))
            return SCM_I_MAKINUM (cend);
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;
          cend--;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cend]));
          if (scm_is_true (res))
            return SCM_I_MAKINUM (cend);
        }
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_skip, "string-skip", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Search through the string @var{s} from left to right, returning\n"
            "the index of the first occurence of a character which\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "does not equal @var{char_pred}, if it is character,\n"
            "\n"
            "@item\n"
            "does not satisify the predicate @var{char_pred}, if it is a\n"
            "procedure,\n"
            "\n"
            "@item\n"
            "is not in the set if @var{char_pred} is a character set.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_skip
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      char cchr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          if (cchr != cstr[cstart])
            return SCM_I_MAKINUM (cstart);
          cstart++;
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          if (!SCM_CHARSET_GET (char_pred, cstr[cstart]))
            return SCM_I_MAKINUM (cstart);
          cstart++;
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cstart]));
          if (scm_is_false (res))
            return SCM_I_MAKINUM (cstart);
          cstart++;
        }
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_skip_right, "string-skip-right", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Search through the string @var{s} from right to left, returning\n"
            "the index of the last occurence of a character which\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "does not equal @var{char_pred}, if it is character,\n"
            "\n"
            "@item\n"
            "does not satisifie the predicate @var{char_pred}, if it is a\n"
            "procedure,\n"
            "\n"
            "@item\n"
            "is not in the set if @var{char_pred} is a character set.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_skip_right
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      char cchr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          cend--;
          if (cchr != cstr[cend])
            return SCM_I_MAKINUM (cend);
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          cend--;
          if (!SCM_CHARSET_GET (char_pred, cstr[cend]))
            return SCM_I_MAKINUM (cend);
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;
          cend--;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cend]));
          if (scm_is_false (res))
            return SCM_I_MAKINUM (cend);
        }
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_count, "string-count", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Return the count of the number of characters in the string\n"
            "@var{s} which\n"
            "\n"
            "@itemize @bullet\n"
            "@item\n"
            "equals @var{char_pred}, if it is character,\n"
            "\n"
            "@item\n"
            "satisifies the predicate @var{char_pred}, if it is a procedure.\n"
            "\n"
            "@item\n"
            "is in the set @var{char_pred}, if it is a character set.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_count
{
  char * cstr;
  int cstart, cend;
  int count = 0;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      char cchr = SCM_CHAR (char_pred);
      while (cstart < cend)
        {
          if (cchr == cstr[cstart])
            count++;
          cstart++;
        }
    }
  else if (SCM_CHARSETP (char_pred))
    {
      while (cstart < cend)
        {
          if (SCM_CHARSET_GET (char_pred, cstr[cstart]))
            count++;
          cstart++;
        }
    }
  else
    {
      SCM_VALIDATE_PROC (2, char_pred);
      while (cstart < cend)
        {
          SCM res;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[cstart]));
          if (scm_is_true (res))
            count++;
          cstart++;
        }
    }
  return SCM_I_MAKINUM (count);
}
#undef FUNC_NAME


/* FIXME::martin: This should definitely get implemented more
   efficiently -- maybe with Knuth-Morris-Pratt, like in the reference
   implementation.  */
SCM_DEFINE (scm_string_contains, "string-contains", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Does string @var{s1} contain string @var{s2}?  Return the index\n"
            "in @var{s1} where @var{s2} occurs as a substring, or false.\n"
            "The optional start/end indices restrict the operation to the\n"
            "indicated substrings.")
#define FUNC_NAME s_scm_string_contains
{
  char * cs1, * cs2;
  int cstart1, cend1, cstart2, cend2;
  int len2, i, j;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cs1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cs2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  len2 = cend2 - cstart2;
  while (cstart1 <= cend1 - len2)
    {
      i = cstart1;
      j = cstart2;
      while (i < cend1 && j < cend2 && cs1[i] == cs2[j])
        {
          i++;
          j++;
        }
      if (j == cend2)
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


/* FIXME::martin: This should definitely get implemented more
   efficiently -- maybe with Knuth-Morris-Pratt, like in the reference
   implementation.  */
SCM_DEFINE (scm_string_contains_ci, "string-contains-ci", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Does string @var{s1} contain string @var{s2}?  Return the index\n"
            "in @var{s1} where @var{s2} occurs as a substring, or false.\n"
            "The optional start/end indices restrict the operation to the\n"
            "indicated substrings.  Character comparison is done\n"
            "case-insensitively.")
#define FUNC_NAME s_scm_string_contains_ci
{
  char * cs1, * cs2;
  int cstart1, cend1, cstart2, cend2;
  int len2, i, j;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cs1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cs2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  len2 = cend2 - cstart2;
  while (cstart1 <= cend1 - len2)
    {
      i = cstart1;
      j = cstart2;
      while (i < cend1 && j < cend2 &&
             scm_c_downcase (cs1[i]) == scm_c_downcase (cs2[j]))
        {
          i++;
          j++;
        }
      if (j == cend2)
        return SCM_I_MAKINUM (cstart1);
      cstart1++;
    }
  return SCM_BOOL_F;
}
#undef FUNC_NAME


/* Helper function for the string uppercase conversion functions.
 * No argument checking is performed.  */
static SCM
string_upcase_x (SCM v, int start, int end)
{
  unsigned long k;

  for (k = start; k < end; ++k)
    SCM_STRING_UCHARS (v) [k] = scm_c_upcase (SCM_STRING_UCHARS (v) [k]);

  return v;
}


/* FIXME::martin: The `S' is to avoid a name clash with the procedure
   in the core, which does not accept start/end indices */
SCM_DEFINE (scm_string_upcase_xS, "string-upcase!", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Destructively upcase every character in @code{str}.\n"
            "\n"
            "@lisp\n"
            "(string-upcase! y)\n"
            "@result{} \"ARRDEFG\"\n"
            "y\n"
            "@result{} \"ARRDEFG\"\n"
            "@end lisp")
#define FUNC_NAME s_scm_string_upcase_xS
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return string_upcase_x (str, cstart, cend);
}
#undef FUNC_NAME


/* FIXME::martin: The `S' is to avoid a name clash with the procedure
   in the core, which does not accept start/end indices */
SCM_DEFINE (scm_string_upcaseS, "string-upcase", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Upcase every character in @code{str}.")
#define FUNC_NAME s_scm_string_upcaseS
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return string_upcase_x (scm_string_copy (str), cstart, cend);
}
#undef FUNC_NAME


/* Helper function for the string lowercase conversion functions.
 * No argument checking is performed.  */
static SCM
string_downcase_x (SCM v, int start, int end)
{
  unsigned long k;

  for (k = start; k < end; ++k)
    SCM_STRING_UCHARS (v) [k] = scm_c_downcase (SCM_STRING_UCHARS (v) [k]);

  return v;
}


/* FIXME::martin: The `S' is to avoid a name clash with the procedure
   in the core, which does not accept start/end indices */
SCM_DEFINE (scm_string_downcase_xS, "string-downcase!", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Destructively downcase every character in @var{str}.\n"
            "\n"
            "@lisp\n"
            "y\n"
            "@result{} \"ARRDEFG\"\n"
            "(string-downcase! y)\n"
            "@result{} \"arrdefg\"\n"
            "y\n"
            "@result{} \"arrdefg\"\n"
            "@end lisp")
#define FUNC_NAME s_scm_string_downcase_xS
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return string_downcase_x (str, cstart, cend);
}
#undef FUNC_NAME


/* FIXME::martin: The `S' is to avoid a name clash with the procedure
   in the core, which does not accept start/end indices */
SCM_DEFINE (scm_string_downcaseS, "string-downcase", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Downcase every character in @var{str}.")
#define FUNC_NAME s_scm_string_downcaseS
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return string_downcase_x (scm_string_copy (str), cstart, cend);
}
#undef FUNC_NAME


/* Helper function for the string capitalization functions.
 * No argument checking is performed.  */
static SCM
string_titlecase_x (SCM str, int start, int end)
{
  unsigned char * sz;
  int i, in_word = 0;

  sz = SCM_STRING_UCHARS (str);
  for(i = start; i < end;  i++)
    {
      if (scm_is_true (scm_char_alphabetic_p (SCM_MAKE_CHAR (sz[i]))))
        {
          if (!in_word)
            {
              sz[i] = scm_c_upcase(sz[i]);
              in_word = 1;
            }
          else
            {
              sz[i] = scm_c_downcase(sz[i]);
            }
        }
      else
        in_word = 0;
    }
  return str;
}


SCM_DEFINE (scm_string_titlecase_x, "string-titlecase!", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Destructively titlecase every first character in a word in\n"
            "@var{str}.")
#define FUNC_NAME s_scm_string_titlecase_x
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return string_titlecase_x (str, cstart, cend);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_titlecase, "string-titlecase", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Titlecase every first character in a word in @var{str}.")
#define FUNC_NAME s_scm_string_titlecase
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  return string_titlecase_x (scm_string_copy (str), cstart, cend);
}
#undef FUNC_NAME


/* Reverse the portion of @var{str} between str[cstart] (including)
   and str[cend] excluding.  */
static void
string_reverse_x (char * str, int cstart, int cend)
{
  char tmp;

  cend--;
  while (cstart < cend)
    {
      tmp = str[cstart];
      str[cstart] = str[cend];
      str[cend] = tmp;
      cstart++;
      cend--;
    }
}


SCM_DEFINE (scm_string_reverse, "string-reverse", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Reverse the string @var{str}.  The optional arguments\n"
            "@var{start} and @var{end} delimit the region of @var{str} to\n"
            "operate on.")
#define FUNC_NAME s_scm_string_reverse
{
  char * cstr;
  int cstart;
  int cend;
  SCM result;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  result = scm_string_copy (str);
  string_reverse_x (SCM_STRING_CHARS (result), cstart, cend);
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_reverse_x, "string-reverse!", 1, 2, 0,
            (SCM str, SCM start, SCM end),
            "Reverse the string @var{str} in-place.  The optional arguments\n"
            "@var{start} and @var{end} delimit the region of @var{str} to\n"
            "operate on.  The return value is unspecified.")
#define FUNC_NAME s_scm_string_reverse_x
{
  char * cstr;
  int cstart;
  int cend;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, str, cstr,
                                    2, start, cstart,
                                    3, end, cend);
  string_reverse_x (SCM_STRING_CHARS (str), cstart, cend);
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_append_shared, "string-append/shared", 0, 0, 1,
            (SCM ls),
            "Like @code{string-append}, but the result may share memory\n"
            "with the argument strings.")
#define FUNC_NAME s_scm_string_append_shared
{
  long i;

  SCM_VALIDATE_REST_ARGUMENT (ls);

  /* Optimize the one-argument case.  */
  i = scm_ilength (ls);
  if (i == 1)
    return SCM_CAR (ls);
  else
    return scm_string_append (ls);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_concatenate, "string-concatenate", 1, 0, 0,
            (SCM ls),
            "Append the elements of @var{ls} (which must be strings)\n"
            "together into a single string.  Guaranteed to return a freshly\n"
            "allocated string.")
#define FUNC_NAME s_scm_string_concatenate
{
  long strings = scm_ilength (ls);
  SCM tmp, result;
  int len = 0;
  char * p;

  /* Validate the string list.  */
  if (strings < 0)
    SCM_WRONG_TYPE_ARG (1, ls);

  /* Calculate the size of the result string.  */
  tmp = ls;
  while (!SCM_NULLP (tmp))
    {
      SCM elt = SCM_CAR (tmp);
      SCM_VALIDATE_STRING (1, elt);
      len += SCM_STRING_LENGTH (elt);
      tmp = SCM_CDR (tmp);
    }
  result = scm_allocate_string (len);

  /* Copy the list elements into the result.  */
  p = SCM_STRING_CHARS (result);
  tmp = ls;
  while (!SCM_NULLP (tmp))
    {
      SCM elt = SCM_CAR (tmp);
      memmove (p, SCM_STRING_CHARS (elt),
               SCM_STRING_LENGTH (elt) * sizeof (char));
      p += SCM_STRING_LENGTH (elt);
      tmp = SCM_CDR (tmp);
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_concatenate_reverse, "string-concatenate-reverse", 1, 2, 0,
            (SCM ls, SCM final_string, SCM end),
            "Without optional arguments, this procedure is equivalent to\n"
            "\n"
            "@smalllisp\n"
            "(string-concatenate (reverse ls))\n"
            "@end smalllisp\n"
            "\n"
            "If the optional argument @var{final_string} is specified, it is\n"
            "consed onto the beginning to @var{ls} before performing the\n"
            "list-reverse and string-concatenate operations.  If @var{end}\n"
            "is given, only the characters of @var{final_string} up to index\n"
            "@var{end} are used.\n"
            "\n"
            "Guaranteed to return a freshly allocated string.")
#define FUNC_NAME s_scm_string_concatenate_reverse
{
  long strings;
  SCM tmp, result;
  size_t len = 0;
  char * p;
  size_t cend = 0;

  /* Check the optional arguments and calculate the additional length
     of the result string.  */
  if (!SCM_UNBNDP (final_string))
    {
      SCM_VALIDATE_STRING (2, final_string);
      if (!SCM_UNBNDP (end))
        {
          cend = scm_to_unsigned_integer (end,
                                          0, SCM_STRING_LENGTH (final_string));
        }
      else
        {
          cend = SCM_STRING_LENGTH (final_string);
        }
      len += cend;
    }
  strings = scm_ilength (ls);
  /* Validate the string list.  */
  if (strings < 0)
    SCM_WRONG_TYPE_ARG (1, ls);

  /* Calculate the length of the result string.  */
  tmp = ls;
  while (!SCM_NULLP (tmp))
    {
      SCM elt = SCM_CAR (tmp);
      SCM_VALIDATE_STRING (1, elt);
      len += SCM_STRING_LENGTH (elt);
      tmp = SCM_CDR (tmp);
    }

  result = scm_allocate_string (len);

  p = SCM_STRING_CHARS (result) + len;

  /* Construct the result string, possibly by using the optional final
     string.  */
  if (!SCM_UNBNDP (final_string))
    {
      p -= cend;
      memmove (p, SCM_STRING_CHARS (final_string), cend * sizeof (char));
    }
  tmp = ls;
  while (!SCM_NULLP (tmp))
    {
      SCM elt = SCM_CAR (tmp);
      p -= SCM_STRING_LENGTH (elt);
      memmove (p, SCM_STRING_CHARS (elt),
               SCM_STRING_LENGTH (elt) * sizeof (char));
      tmp = SCM_CDR (tmp);
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_concatenate_shared, "string-concatenate/shared", 1, 0, 0,
            (SCM ls),
            "Like @code{string-concatenate}, but the result may share memory\n"
            "with the strings in the list @var{ls}.")
#define FUNC_NAME s_scm_string_concatenate_shared
{
  /* Optimize the one-string case.  */
  long i = scm_ilength (ls);
  if (i == 1)
    {
      SCM_VALIDATE_STRING (1, SCM_CAR (ls));
      return SCM_CAR (ls);
    }
  return scm_string_concatenate (ls);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_concatenate_reverse_shared, "string-concatenate-reverse/shared", 1, 2, 0,
            (SCM ls, SCM final_string, SCM end),
            "Like @code{string-concatenate-reverse}, but the result may\n"
            "share memory with the the strings in the @var{ls} arguments.")
#define FUNC_NAME s_scm_string_concatenate_reverse_shared
{
  /* Just call the non-sharing version.  */
  return scm_string_concatenate_reverse (ls, final_string, end);
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_map, "string-map", 2, 2, 0,
            (SCM proc, SCM s, SCM start, SCM end),
            "@var{proc} is a char->char procedure, it is mapped over\n"
            "@var{s}.  The order in which the procedure is applied to the\n"
            "string elements is not specified.")
#define FUNC_NAME s_scm_string_map
{
  char * cstr, *p;
  int cstart, cend;
  SCM result;

  SCM_VALIDATE_PROC (1, proc);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  result = scm_allocate_string (cend - cstart);
  p = SCM_STRING_CHARS (result);
  while (cstart < cend)
    {
      unsigned int c =  (unsigned char) cstr[cstart];
      SCM ch = scm_call_1 (proc, SCM_MAKE_CHAR (c));
      if (!SCM_CHARP (ch))
        SCM_MISC_ERROR ("procedure ~S returned non-char", scm_list_1 (proc));
      cstart++;
      *p++ = SCM_CHAR (ch);
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_map_x, "string-map!", 2, 2, 0,
            (SCM proc, SCM s, SCM start, SCM end),
            "@var{proc} is a char->char procedure, it is mapped over\n"
            "@var{s}.  The order in which the procedure is applied to the\n"
            "string elements is not specified.  The string @var{s} is\n"
            "modified in-place, the return value is not specified.")
#define FUNC_NAME s_scm_string_map_x
{
  char * cstr, *p;
  int cstart, cend;

  SCM_VALIDATE_PROC (1, proc);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  p = SCM_STRING_CHARS (s) + cstart;
  while (cstart < cend)
    {
      unsigned int c =  (unsigned char) cstr[cstart];
      SCM ch = scm_call_1 (proc, SCM_MAKE_CHAR (c));
      if (!SCM_CHARP (ch))
        SCM_MISC_ERROR ("procedure ~S returned non-char", scm_list_1 (proc));
      cstart++;
      *p++ = SCM_CHAR (ch);
    }
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_fold, "string-fold", 3, 2, 0,
            (SCM kons, SCM knil, SCM s, SCM start, SCM end),
            "Fold @var{kons} over the characters of @var{s}, with @var{knil}\n"
            "as the terminating element, from left to right.  @var{kons}\n"
            "must expect two arguments: The actual character and the last\n"
            "result of @var{kons}' application.")
#define FUNC_NAME s_scm_string_fold
{
  char * cstr;
  int cstart, cend;
  SCM result;

  SCM_VALIDATE_PROC (1, kons);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (3, s, cstr,
                                    4, start, cstart,
                                    5, end, cend);
  result = knil;
  while (cstart < cend)
    {
      unsigned int c = (unsigned char) cstr[cstart];
      result = scm_call_2 (kons, SCM_MAKE_CHAR (c), result);
      cstart++;
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_fold_right, "string-fold-right", 3, 2, 0,
            (SCM kons, SCM knil, SCM s, SCM start, SCM end),
            "Fold @var{kons} over the characters of @var{s}, with @var{knil}\n"
            "as the terminating element, from right to left.  @var{kons}\n"
            "must expect two arguments: The actual character and the last\n"
            "result of @var{kons}' application.")
#define FUNC_NAME s_scm_string_fold_right
{
  char * cstr;
  int cstart, cend;
  SCM result;

  SCM_VALIDATE_PROC (1, kons);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (3, s, cstr,
                                    4, start, cstart,
                                    5, end, cend);
  result = knil;
  while (cstart < cend)
    {
      unsigned int c  = (unsigned char) cstr[cend - 1];
      result = scm_call_2 (kons, SCM_MAKE_CHAR (c), result);
      cend--;
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_unfold, "string-unfold", 4, 2, 0,
            (SCM p, SCM f, SCM g, SCM seed, SCM base, SCM make_final),
            "@itemize @bullet\n"
            "@item @var{g} is used to generate a series of @emph{seed}\n"
            "values from the initial @var{seed}: @var{seed}, (@var{g}\n"
            "@var{seed}), (@var{g}^2 @var{seed}), (@var{g}^3 @var{seed}),\n"
            "@dots{}\n"
            "@item @var{p} tells us when to stop -- when it returns true\n"
            "when applied to one of these seed values.\n"
            "@item @var{f} maps each seed value to the corresponding\n"
            "character in the result string.  These chars are assembled\n"
            "into the string in a left-to-right order.\n"
            "@item @var{base} is the optional initial/leftmost portion\n"
            "of the constructed string; it default to the empty\n"
            "string.\n"
            "@item @var{make_final} is applied to the terminal seed\n"
            "value (on which @var{p} returns true) to produce\n"
            "the final/rightmost portion of the constructed string.\n"
            "It defaults to @code{(lambda (x) "")}.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_unfold
{
  SCM res, ans;

  SCM_VALIDATE_PROC (1, p);
  SCM_VALIDATE_PROC (2, f);
  SCM_VALIDATE_PROC (3, g);
  if (!SCM_UNBNDP (base))
    {
      SCM_VALIDATE_STRING (5, base);
      ans = base;
    }
  else
    ans = scm_allocate_string (0);
  if (!SCM_UNBNDP (make_final))
    SCM_VALIDATE_PROC (6, make_final);

  res = scm_call_1 (p, seed);
  while (scm_is_false (res))
    {
      SCM str;
      SCM ch = scm_call_1 (f, seed);
      if (!SCM_CHARP (ch))
        SCM_MISC_ERROR ("procedure ~S returned non-char", scm_list_1 (f));
      str = scm_allocate_string (1);
      *SCM_STRING_CHARS (str) = SCM_CHAR (ch);

      ans = scm_string_append (scm_list_2 (ans, str));
      seed = scm_call_1 (g, seed);
      res = scm_call_1 (p, seed);
    }
  if (!SCM_UNBNDP (make_final))
    {
      res = scm_call_1 (make_final, seed);
      return scm_string_append (scm_list_2 (ans, res));
    }
  else
    return ans;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_unfold_right, "string-unfold-right", 4, 2, 0,
            (SCM p, SCM f, SCM g, SCM seed, SCM base, SCM make_final),
            "@itemize @bullet\n"
            "@item @var{g} is used to generate a series of @emph{seed}\n"
            "values from the initial @var{seed}: @var{seed}, (@var{g}\n"
            "@var{seed}), (@var{g}^2 @var{seed}), (@var{g}^3 @var{seed}),\n"
            "@dots{}\n"
            "@item @var{p} tells us when to stop -- when it returns true\n"
            "when applied to one of these seed values.\n"
            "@item @var{f} maps each seed value to the corresponding\n"
            "character in the result string.  These chars are assembled\n"
            "into the string in a right-to-left order.\n"
            "@item @var{base} is the optional initial/rightmost portion\n"
            "of the constructed string; it default to the empty\n"
            "string.\n"
            "@item @var{make_final} is applied to the terminal seed\n"
            "value (on which @var{p} returns true) to produce\n"
            "the final/leftmost portion of the constructed string.\n"
            "It defaults to @code{(lambda (x) "")}.\n"
            "@end itemize")
#define FUNC_NAME s_scm_string_unfold_right
{
  SCM res, ans;

  SCM_VALIDATE_PROC (1, p);
  SCM_VALIDATE_PROC (2, f);
  SCM_VALIDATE_PROC (3, g);
  if (!SCM_UNBNDP (base))
    {
      SCM_VALIDATE_STRING (5, base);
      ans = base;
    }
  else
    ans = scm_allocate_string (0);
  if (!SCM_UNBNDP (make_final))
    SCM_VALIDATE_PROC (6, make_final);

  res = scm_call_1 (p, seed);
  while (scm_is_false (res))
    {
      SCM str;
      SCM ch = scm_call_1 (f, seed);
      if (!SCM_CHARP (ch))
        SCM_MISC_ERROR ("procedure ~S returned non-char", scm_list_1 (f));
      str = scm_allocate_string (1);
      *SCM_STRING_CHARS (str) = SCM_CHAR (ch);

      ans = scm_string_append (scm_list_2 (str, ans));
      seed = scm_call_1 (g, seed);
      res = scm_call_1 (p, seed);
    }
  if (!SCM_UNBNDP (make_final))
    {
      res = scm_call_1 (make_final, seed);
      return scm_string_append (scm_list_2 (res, ans));
    }
  else
    return ans;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_for_each, "string-for-each", 2, 2, 0,
            (SCM proc, SCM s, SCM start, SCM end),
            "@var{proc} is mapped over @var{s} in left-to-right order.  The\n"
            "return value is not specified.")
#define FUNC_NAME s_scm_string_for_each
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_PROC (1, proc);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  while (cstart < cend)
    {
      unsigned int c = (unsigned char) cstr[cstart];
      scm_call_1 (proc, SCM_MAKE_CHAR (c));
      cstart++;
    }
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_string_for_each_index, "string-for-each-index", 2, 2, 0,
            (SCM proc, SCM s, SCM start, SCM end),
            "@var{proc} is mapped over @var{s} in left-to-right order.  The\n"
            "return value is not specified.")
#define FUNC_NAME s_scm_string_for_each
{
  char * cstr;
  int cstart, cend;

  SCM_VALIDATE_PROC (1, proc);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  while (cstart < cend)
    {
      scm_call_1 (proc, SCM_I_MAKINUM (cstart));
      cstart++;
    }
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_xsubstring, "xsubstring", 2, 3, 0,
            (SCM s, SCM from, SCM to, SCM start, SCM end),
            "This is the @emph{extended substring} procedure that implements\n"
            "replicated copying of a substring of some string.\n"
            "\n"
            "@var{s} is a string, @var{start} and @var{end} are optional\n"
            "arguments that demarcate a substring of @var{s}, defaulting to\n"
            "0 and the length of @var{s}.  Replicate this substring up and\n"
            "down index space, in both the positive and negative directions.\n"
            "@code{xsubstring} returns the substring of this string\n"
            "beginning at index @var{from}, and ending at @var{to}, which\n"
            "defaults to @var{from} + (@var{end} - @var{start}).")
#define FUNC_NAME s_scm_xsubstring
{
  char * cs, * p;
  size_t cstart, cend, cfrom, cto;
  SCM result;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cs,
                                    4, start, cstart,
                                    5, end, cend);
  cfrom = scm_to_size_t (from);
  if (SCM_UNBNDP (to))
    cto = cfrom + (cend - cstart);
  else
    cto = scm_to_size_t (to);
  if (cstart == cend && cfrom != cto)
    SCM_MISC_ERROR ("start and end indices must not be equal", SCM_EOL);

  result = scm_allocate_string (cto - cfrom);

  p = SCM_STRING_CHARS (result);
  while (cfrom < cto)
    {
      int t = ((cfrom < 0) ? -cfrom : cfrom) % (cend - cstart);
      if (cfrom < 0)
        *p = cs[(cend - cstart) - t];
      else
        *p = cs[t];
      cfrom++;
      p++;
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_xcopy_x, "string-xcopy!", 4, 3, 0,
            (SCM target, SCM tstart, SCM s, SCM sfrom, SCM sto, SCM start, SCM end),
            "Exactly the same as @code{xsubstring}, but the extracted text\n"
            "is written into the string @var{target} starting at index\n"
            "@var{tstart}.  The operation is not defined if @code{(eq?\n"
            "@var{target} @var{s})} or these arguments share storage -- you\n"
            "cannot copy a string on top of itself.")
#define FUNC_NAME s_scm_string_xcopy_x
{
  char * ctarget, * cs, * p;
  size_t ctstart, csfrom, csto, cstart, cend;
  SCM dummy = SCM_UNDEFINED;
  int cdummy;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, target, ctarget,
                                    2, tstart, ctstart,
                                    2, dummy, cdummy);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (3, s, cs,
                                    6, start, cstart,
                                    7, end, cend);
  csfrom = scm_to_size_t (sfrom);
  if (SCM_UNBNDP (sto))
    csto = csfrom + (cend - cstart);
  else
    csto = scm_to_size_t (sto); 
  if (cstart == cend && csfrom != csto)
    SCM_MISC_ERROR ("start and end indices must not be equal", SCM_EOL);
  SCM_ASSERT_RANGE (1, tstart,
                    ctstart + (csto - csfrom) <= SCM_STRING_LENGTH (target));

  p = ctarget + ctstart;
  while (csfrom < csto)
    {
      int t = ((csfrom < 0) ? -csfrom : csfrom) % (cend - cstart);
      if (csfrom < 0)
        *p = cs[(cend - cstart) - t];
      else
        *p = cs[t];
      csfrom++;
      p++;
    }
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_replace, "string-replace", 2, 4, 0,
            (SCM s1, SCM s2, SCM start1, SCM end1, SCM start2, SCM end2),
            "Return the string @var{s1}, but with the characters\n"
            "@var{start1} @dots{} @var{end1} replaced by the characters\n"
            "@var{start2} @dots{} @var{end2} from @var{s2}.")
#define FUNC_NAME s_scm_string_replace
{
  char * cstr1, * cstr2, * p;
  size_t cstart1, cend1, cstart2, cend2;
  SCM result;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s1, cstr1,
                                    3, start1, cstart1,
                                    4, end1, cend1);
  SCM_VALIDATE_SUBSTRING_SPEC_COPY (2, s2, cstr2,
                                    5, start2, cstart2,
                                    6, end2, cend2);
  result = scm_allocate_string (cstart1 + (cend2 - cstart2) +
                                SCM_STRING_LENGTH (s1) - cend1);
  p = SCM_STRING_CHARS (result);
  memmove (p, cstr1, cstart1 * sizeof (char));
  memmove (p + cstart1, cstr2 + cstart2, (cend2 - cstart2) * sizeof (char));
  memmove (p + cstart1 + (cend2 - cstart2),
           cstr1 + cend1,
           (SCM_STRING_LENGTH (s1) - cend1) * sizeof (char));
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_tokenize, "string-tokenize", 1, 3, 0,
            (SCM s, SCM token_set, SCM start, SCM end),
            "Split the string @var{s} into a list of substrings, where each\n"
            "substring is a maximal non-empty contiguous sequence of\n"
            "characters from the character set @var{token_set}, which\n"
            "defaults to @code{char-set:graphic} from module (srfi srfi-14).\n"
            "If @var{start} or @var{end} indices are provided, they restrict\n"
            "@code{string-tokenize} to operating on the indicated substring\n"
            "of @var{s}.")
#define FUNC_NAME s_scm_string_tokenize
{
  char * cstr;
  size_t cstart, cend;
  SCM result = SCM_EOL;

  static SCM charset_graphic = SCM_BOOL_F;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);

  if (SCM_UNBNDP (token_set))
    {
      if (charset_graphic == SCM_BOOL_F)
        {
          SCM srfi_14_module = scm_c_resolve_module ("srfi srfi-14");
          SCM charset_graphic_var = scm_c_module_lookup (srfi_14_module,
                                                         "char-set:graphic");
          charset_graphic =
            scm_permanent_object (SCM_VARIABLE_REF (charset_graphic_var));
        }
      token_set = charset_graphic;
    }

  if (SCM_CHARSETP (token_set))
    {
      int idx;

      while (cstart < cend)
        {
          while (cstart < cend)
            {
              if (SCM_CHARSET_GET (token_set, cstr[cend - 1]))
                break;
              cend--;
            }
          if (cstart >= cend)
            break;
          idx = cend;
          while (cstart < cend)
            {
              if (!SCM_CHARSET_GET (token_set, cstr[cend - 1]))
                break;
              cend--;
            }
          result = scm_cons (scm_mem2string (cstr + cend, idx - cend), result);
        }
    }
  else SCM_WRONG_TYPE_ARG (2, token_set);
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_filter, "string-filter", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Filter the string @var{s}, retaining only those characters that\n"
            "satisfy the @var{char_pred} argument.  If the argument is a\n"
            "procedure, it is applied to each character as a predicate, if\n"
            "it is a character, it is tested for equality and if it is a\n"
            "character set, it is tested for membership.")
#define FUNC_NAME s_scm_string_filter
{
  char * cstr;
  size_t cstart, cend;
  SCM result;
  int idx;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      SCM ls = SCM_EOL;
      char chr;

      chr = SCM_CHAR (char_pred);
      idx = cstart;
      while (idx < cend)
        {
          if (cstr[idx] == chr)
            ls = scm_cons (SCM_MAKE_CHAR (cstr[idx]), ls);
          idx++;
        }
      result = scm_reverse_list_to_string (ls);
    }
  else if (SCM_CHARSETP (char_pred))
    {
      SCM ls = SCM_EOL;

      idx = cstart;
      while (idx < cend)
        {
          if (SCM_CHARSET_GET (char_pred, cstr[idx]))
            ls = scm_cons (SCM_MAKE_CHAR (cstr[idx]), ls);
          idx++;
        }
      result = scm_reverse_list_to_string (ls);
    }
  else
    {
      SCM ls = SCM_EOL;

      SCM_VALIDATE_PROC (2, char_pred);
      idx = cstart;
      while (idx < cend)
        {
          SCM res;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[idx]));
          if (scm_is_true (res))
            ls = scm_cons (SCM_MAKE_CHAR (cstr[idx]), ls);
          idx++;
        }
      result = scm_reverse_list_to_string (ls);
    }
  return result;
}
#undef FUNC_NAME


SCM_DEFINE (scm_string_delete, "string-delete", 2, 2, 0,
            (SCM s, SCM char_pred, SCM start, SCM end),
            "Filter the string @var{s}, retaining only those characters that\n"
            "do not satisfy the @var{char_pred} argument.  If the argument\n"
            "is a procedure, it is applied to each character as a predicate,\n"
            "if it is a character, it is tested for equality and if it is a\n"
            "character set, it is tested for membership.")
#define FUNC_NAME s_scm_string_delete
{
  char * cstr;
  size_t cstart, cend;
  SCM result;
  int idx;

  SCM_VALIDATE_SUBSTRING_SPEC_COPY (1, s, cstr,
                                    3, start, cstart,
                                    4, end, cend);
  if (SCM_CHARP (char_pred))
    {
      SCM ls = SCM_EOL;
      char chr;

      chr = SCM_CHAR (char_pred);
      idx = cstart;
      while (idx < cend)
        {
          if (cstr[idx] != chr)
            ls = scm_cons (SCM_MAKE_CHAR (cstr[idx]), ls);
          idx++;
        }
      result = scm_reverse_list_to_string (ls);
    }
  else if (SCM_CHARSETP (char_pred))
    {
      SCM ls = SCM_EOL;

      idx = cstart;
      while (idx < cend)
        {
          if (!SCM_CHARSET_GET (char_pred, cstr[idx]))
            ls = scm_cons (SCM_MAKE_CHAR (cstr[idx]), ls);
          idx++;
        }
      result = scm_reverse_list_to_string (ls);
    }
  else
    {
      SCM ls = SCM_EOL;

      SCM_VALIDATE_PROC (2, char_pred);
      idx = cstart;
      while (idx < cend)
        {
          SCM res;
          res = scm_call_1 (char_pred, SCM_MAKE_CHAR (cstr[idx]));
          if (scm_is_false (res))
            ls = scm_cons (SCM_MAKE_CHAR (cstr[idx]), ls);
          idx++;
        }
      result = scm_reverse_list_to_string (ls);
    }
  return result;
}
#undef FUNC_NAME


/* Initialize the SRFI-13 module.  This function will be called by the
   loading Scheme module.  */
void
scm_init_srfi_13 (void)
{
  /* We initialize the SRFI-14 module here, because the string
     primitives need the charset smob type created by that module.  */
  scm_c_init_srfi_14 ();

  /* Install the string primitives.  */
#include "srfi/srfi-13.x"
}

/* End of srfi-13.c.  */