/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * 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 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.
 */

/*
 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/.
 */

/*
 * MT safe
 */

#include "config.h"

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <string.h>
#include <locale.h>
#include <errno.h>
#include <ctype.h>              /* For tolower() */

#ifdef HAVE_XLOCALE_H
/* Needed on BSD/OS X for e.g. strtod_l */
#include <xlocale.h>
#endif

#ifdef G_OS_WIN32
#include <windows.h>
#endif

/* do not include <unistd.h> here, it may interfere with g_strsignal() */

#include "gstrfuncs.h"

#include "gprintf.h"
#include "gprintfint.h"
#include "glibintl.h"


/**
 * SECTION:string_utils
 * @title: String Utility Functions
 * @short_description: various string-related functions
 *
 * This section describes a number of utility functions for creating,
 * duplicating, and manipulating strings.
 *
 * Note that the functions g_printf(), g_fprintf(), g_sprintf(),
 * g_snprintf(), g_vprintf(), g_vfprintf(), g_vsprintf() and g_vsnprintf()
 * are declared in the header <filename>gprintf.h</filename> which is
 * <emphasis>not</emphasis> included in <filename>glib.h</filename>
 * (otherwise using <filename>glib.h</filename> would drag in
 * <filename>stdio.h</filename>), so you'll have to explicitly include
 * <literal>&lt;glib/gprintf.h&gt;</literal> in order to use the GLib
 * printf() functions.
 *
 * <para id="string-precision">While you may use the printf() functions
 * to format UTF-8 strings, notice that the precision of a
 * <literal>&percnt;Ns</literal> parameter is interpreted as the
 * number of <emphasis>bytes</emphasis>, not <emphasis>characters</emphasis>
 * to print. On top of that, the GNU libc implementation of the printf()
 * functions has the "feature" that it checks that the string given for
 * the <literal>&percnt;Ns</literal> parameter consists of a whole number
 * of characters in the current encoding. So, unless you are sure you are
 * always going to be in an UTF-8 locale or your know your text is restricted
 * to ASCII, avoid using <literal>&percnt;Ns</literal>. If your intention is
 * to format strings for a certain number of columns, then
 * <literal>&percnt;Ns</literal> is not a correct solution anyway, since it
 * fails to take wide characters (see g_unichar_iswide()) into account.
 * </para>
 */

/**
 * g_ascii_isalnum:
 * @c: any character
 *
 * Determines whether a character is alphanumeric.
 *
 * Unlike the standard C library isalnum() function, this only
 * recognizes standard ASCII letters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need to
 * cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII alphanumeric character
 */

/**
 * g_ascii_isalpha:
 * @c: any character
 *
 * Determines whether a character is alphabetic (i.e. a letter).
 *
 * Unlike the standard C library isalpha() function, this only
 * recognizes standard ASCII letters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need to
 * cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII alphabetic character
 */

/**
 * g_ascii_iscntrl:
 * @c: any character
 *
 * Determines whether a character is a control character.
 *
 * Unlike the standard C library iscntrl() function, this only
 * recognizes standard ASCII control characters and ignores the
 * locale, returning %FALSE for all non-ASCII characters. Also,
 * unlike the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need to
 * cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII control character.
 */

/**
 * g_ascii_isdigit:
 * @c: any character
 *
 * Determines whether a character is digit (0-9).
 *
 * Unlike the standard C library isdigit() function, this takes
 * a <type>char</type>, not an <type>int</type>, so don't call it
 * on <literal>EOF</literal>, but no need to cast to #guchar before passing a possibly
 * non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII digit.
 */

/**
 * g_ascii_isgraph:
 * @c: any character
 *
 * Determines whether a character is a printing character and not a space.
 *
 * Unlike the standard C library isgraph() function, this only
 * recognizes standard ASCII characters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need
 * to cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII printing character other than space.
 */

/**
 * g_ascii_islower:
 * @c: any character
 *
 * Determines whether a character is an ASCII lower case letter.
 *
 * Unlike the standard C library islower() function, this only
 * recognizes standard ASCII letters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need
 * to worry about casting to #guchar before passing a possibly
 * non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII lower case letter
 */

/**
 * g_ascii_isprint:
 * @c: any character
 *
 * Determines whether a character is a printing character.
 *
 * Unlike the standard C library isprint() function, this only
 * recognizes standard ASCII characters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need
 * to cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII printing character.
 */

/**
 * g_ascii_ispunct:
 * @c: any character
 *
 * Determines whether a character is a punctuation character.
 *
 * Unlike the standard C library ispunct() function, this only
 * recognizes standard ASCII letters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need to
 * cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII punctuation character.
 */

/**
 * g_ascii_isspace:
 * @c: any character
 *
 * Determines whether a character is a white-space character.
 *
 * Unlike the standard C library isspace() function, this only
 * recognizes standard ASCII white-space and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need to
 * cast to #guchar before passing a possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII white-space character
 */

/**
 * g_ascii_isupper:
 * @c: any character
 *
 * Determines whether a character is an ASCII upper case letter.
 *
 * Unlike the standard C library isupper() function, this only
 * recognizes standard ASCII letters and ignores the locale,
 * returning %FALSE for all non-ASCII characters. Also, unlike
 * the standard library function, this takes a <type>char</type>,
 * not an <type>int</type>, so don't call it on <literal>EOF</literal>, but no need to
 * worry about casting to #guchar before passing a possibly non-ASCII
 * character in.
 *
 * Returns: %TRUE if @c is an ASCII upper case letter
 */

/**
 * g_ascii_isxdigit:
 * @c: any character
 *
 * Determines whether a character is a hexadecimal-digit character.
 *
 * Unlike the standard C library isxdigit() function, this takes
 * a <type>char</type>, not an <type>int</type>, so don't call it
 * on <literal>EOF</literal>, but no need to cast to #guchar before passing a
 * possibly non-ASCII character in.
 *
 * Returns: %TRUE if @c is an ASCII hexadecimal-digit character.
 */

/**
 * G_ASCII_DTOSTR_BUF_SIZE:
 *
 * A good size for a buffer to be passed into g_ascii_dtostr().
 * It is guaranteed to be enough for all output of that function
 * on systems with 64bit IEEE-compatible doubles.
 *
 * The typical usage would be something like:
 * |[
 *   char buf[G_ASCII_DTOSTR_BUF_SIZE];
 *
 *   fprintf (out, "value=&percnt;s\n", g_ascii_dtostr (buf, sizeof (buf), value));
 * ]|
 */

/**
 * g_strstrip:
 * @string: a string to remove the leading and trailing whitespace from
 *
 * Removes leading and trailing whitespace from a string.
 * See g_strchomp() and g_strchug().
 *
 * Returns: @string
 */

/**
 * G_STR_DELIMITERS:
 *
 * The standard delimiters, used in g_strdelimit().
 */

static const guint16 ascii_table_data[256] = {
  0x004, 0x004, 0x004, 0x004, 0x004, 0x004, 0x004, 0x004,
  0x004, 0x104, 0x104, 0x004, 0x104, 0x104, 0x004, 0x004,
  0x004, 0x004, 0x004, 0x004, 0x004, 0x004, 0x004, 0x004,
  0x004, 0x004, 0x004, 0x004, 0x004, 0x004, 0x004, 0x004,
  0x140, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0,
  0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0,
  0x459, 0x459, 0x459, 0x459, 0x459, 0x459, 0x459, 0x459,
  0x459, 0x459, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0,
  0x0d0, 0x653, 0x653, 0x653, 0x653, 0x653, 0x653, 0x253,
  0x253, 0x253, 0x253, 0x253, 0x253, 0x253, 0x253, 0x253,
  0x253, 0x253, 0x253, 0x253, 0x253, 0x253, 0x253, 0x253,
  0x253, 0x253, 0x253, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x0d0,
  0x0d0, 0x473, 0x473, 0x473, 0x473, 0x473, 0x473, 0x073,
  0x073, 0x073, 0x073, 0x073, 0x073, 0x073, 0x073, 0x073,
  0x073, 0x073, 0x073, 0x073, 0x073, 0x073, 0x073, 0x073,
  0x073, 0x073, 0x073, 0x0d0, 0x0d0, 0x0d0, 0x0d0, 0x004
  /* the upper 128 are all zeroes */
};

const guint16 * const g_ascii_table = ascii_table_data;

#if defined (HAVE_NEWLOCALE) && \
    defined (HAVE_USELOCALE) && \
    defined (HAVE_STRTOD_L) && \
    defined (HAVE_STRTOULL_L) && \
    defined (HAVE_STRTOLL_L)
#define USE_XLOCALE 1
#endif

#ifdef USE_XLOCALE
static locale_t
get_C_locale (void)
{
  static gsize initialized = FALSE;
  static locale_t C_locale = NULL;

  if (g_once_init_enter (&initialized))
    {
      C_locale = newlocale (LC_ALL_MASK, "C", NULL);
      g_once_init_leave (&initialized, TRUE);
    }

  return C_locale;
}
#endif

/**
 * g_strdup:
 * @str: the string to duplicate
 *
 * Duplicates a string. If @str is %NULL it returns %NULL.
 * The returned string should be freed with g_free()
 * when no longer needed.
 *
 * Returns: a newly-allocated copy of @str
 */
gchar*
g_strdup (const gchar *str)
{
  gchar *new_str;
  gsize length;

  if (str)
    {
      length = strlen (str) + 1;
      new_str = g_new (char, length);
      memcpy (new_str, str, length);
    }
  else
    new_str = NULL;

  return new_str;
}

/**
 * g_memdup:
 * @mem: the memory to copy.
 * @byte_size: the number of bytes to copy.
 *
 * Allocates @byte_size bytes of memory, and copies @byte_size bytes into it
 * from @mem. If @mem is %NULL it returns %NULL.
 *
 * Returns: a pointer to the newly-allocated copy of the memory, or %NULL if @mem
 *  is %NULL.
 */
gpointer
g_memdup (gconstpointer mem,
          guint         byte_size)
{
  gpointer new_mem;

  if (mem)
    {
      new_mem = g_malloc (byte_size);
      memcpy (new_mem, mem, byte_size);
    }
  else
    new_mem = NULL;

  return new_mem;
}

/**
 * g_strndup:
 * @str: the string to duplicate
 * @n: the maximum number of bytes to copy from @str
 *
 * Duplicates the first @n bytes of a string, returning a newly-allocated
 * buffer @n + 1 bytes long which will always be nul-terminated.
 * If @str is less than @n bytes long the buffer is padded with nuls.
 * If @str is %NULL it returns %NULL.
 * The returned value should be freed when no longer needed.
 *
 * <note><para>
 * To copy a number of characters from a UTF-8 encoded string, use
 * g_utf8_strncpy() instead.
 * </para></note>
 *
 * Returns: a newly-allocated buffer containing the first @n bytes
 *          of @str, nul-terminated
 */
gchar*
g_strndup (const gchar *str,
           gsize        n)
{
  gchar *new_str;

  if (str)
    {
      new_str = g_new (gchar, n + 1);
      strncpy (new_str, str, n);
      new_str[n] = '\0';
    }
  else
    new_str = NULL;

  return new_str;
}

/**
 * g_strnfill:
 * @length: the length of the new string
 * @fill_char: the byte to fill the string with
 *
 * Creates a new string @length bytes long filled with @fill_char.
 * The returned string should be freed when no longer needed.
 *
 * Returns: a newly-allocated string filled the @fill_char
 */
gchar*
g_strnfill (gsize length,
            gchar fill_char)
{
  gchar *str;

  str = g_new (gchar, length + 1);
  memset (str, (guchar)fill_char, length);
  str[length] = '\0';

  return str;
}

/**
 * g_stpcpy:
 * @dest: destination buffer.
 * @src: source string.
 *
 * Copies a nul-terminated string into the dest buffer, include the
 * trailing nul, and return a pointer to the trailing nul byte.
 * This is useful for concatenating multiple strings together
 * without having to repeatedly scan for the end.
 *
 * Return value: a pointer to trailing nul byte.
 **/
gchar *
g_stpcpy (gchar       *dest,
          const gchar *src)
{
#ifdef HAVE_STPCPY
  g_return_val_if_fail (dest != NULL, NULL);
  g_return_val_if_fail (src != NULL, NULL);
  return stpcpy (dest, src);
#else
  register gchar *d = dest;
  register const gchar *s = src;

  g_return_val_if_fail (dest != NULL, NULL);
  g_return_val_if_fail (src != NULL, NULL);
  do
    *d++ = *s;
  while (*s++ != '\0');

  return d - 1;
#endif
}

/**
 * g_strdup_vprintf:
 * @format: a standard printf() format string, but notice
 *     <link linkend="string-precision">string precision pitfalls</link>
 * @args: the list of parameters to insert into the format string
 *
 * Similar to the standard C vsprintf() function but safer, since it
 * calculates the maximum space required and allocates memory to hold
 * the result. The returned string should be freed with g_free() when
 * no longer needed.
 *
 * See also g_vasprintf(), which offers the same functionality, but
 * additionally returns the length of the allocated string.
 *
 * Returns: a newly-allocated string holding the result
 */
gchar*
g_strdup_vprintf (const gchar *format,
                  va_list      args)
{
  gchar *string = NULL;

  g_vasprintf (&string, format, args);

  return string;
}

/**
 * g_strdup_printf:
 * @format: a standard printf() format string, but notice
 *     <link linkend="string-precision">string precision pitfalls</link>
 * @...: the parameters to insert into the format string
 *
 * Similar to the standard C sprintf() function but safer, since it
 * calculates the maximum space required and allocates memory to hold
 * the result. The returned string should be freed with g_free() when no
 * longer needed.
 *
 * Returns: a newly-allocated string holding the result
 */
gchar*
g_strdup_printf (const gchar *format,
                 ...)
{
  gchar *buffer;
  va_list args;

  va_start (args, format);
  buffer = g_strdup_vprintf (format, args);
  va_end (args);

  return buffer;
}

/**
 * g_strconcat:
 * @string1: the first string to add, which must not be %NULL
 * @...: a %NULL-terminated list of strings to append to the string
 *
 * Concatenates all of the given strings into one long string.
 * The returned string should be freed with g_free() when no longer needed.
 *
 * Note that this function is usually not the right function to use to
 * assemble a translated message from pieces, since proper translation
 * often requires the pieces to be reordered.
 *
 * <warning><para>The variable argument list <emphasis>must</emphasis> end
 * with %NULL. If you forget the %NULL, g_strconcat() will start appending
 * random memory junk to your string.</para></warning>
 *
 * Returns: a newly-allocated string containing all the string arguments
 */
gchar*
g_strconcat (const gchar *string1, ...)
{
  gsize   l;
  va_list args;
  gchar   *s;
  gchar   *concat;
  gchar   *ptr;

  if (!string1)
    return NULL;

  l = 1 + strlen (string1);
  va_start (args, string1);
  s = va_arg (args, gchar*);
  while (s)
    {
      l += strlen (s);
      s = va_arg (args, gchar*);
    }
  va_end (args);

  concat = g_new (gchar, l);
  ptr = concat;

  ptr = g_stpcpy (ptr, string1);
  va_start (args, string1);
  s = va_arg (args, gchar*);
  while (s)
    {
      ptr = g_stpcpy (ptr, s);
      s = va_arg (args, gchar*);
    }
  va_end (args);

  return concat;
}

/**
 * g_strtod:
 * @nptr:    the string to convert to a numeric value.
 * @endptr:  if non-%NULL, it returns the character after
 *           the last character used in the conversion.
 *
 * Converts a string to a #gdouble value.
 * It calls the standard strtod() function to handle the conversion, but
 * if the string is not completely converted it attempts the conversion
 * again with g_ascii_strtod(), and returns the best match.
 *
 * This function should seldom be used. The normal situation when reading
 * numbers not for human consumption is to use g_ascii_strtod(). Only when
 * you know that you must expect both locale formatted and C formatted numbers
 * should you use this. Make sure that you don't pass strings such as comma
 * separated lists of values, since the commas may be interpreted as a decimal
 * point in some locales, causing unexpected results.
 *
 * Return value: the #gdouble value.
 **/
gdouble
g_strtod (const gchar *nptr,
          gchar      **endptr)
{
  gchar *fail_pos_1;
  gchar *fail_pos_2;
  gdouble val_1;
  gdouble val_2 = 0;

  g_return_val_if_fail (nptr != NULL, 0);

  fail_pos_1 = NULL;
  fail_pos_2 = NULL;

  val_1 = strtod (nptr, &fail_pos_1);

  if (fail_pos_1 && fail_pos_1[0] != 0)
    val_2 = g_ascii_strtod (nptr, &fail_pos_2);

  if (!fail_pos_1 || fail_pos_1[0] == 0 || fail_pos_1 >= fail_pos_2)
    {
      if (endptr)
        *endptr = fail_pos_1;
      return val_1;
    }
  else
    {
      if (endptr)
        *endptr = fail_pos_2;
      return val_2;
    }
}

/**
 * g_ascii_strtod:
 * @nptr:    the string to convert to a numeric value.
 * @endptr:  if non-%NULL, it returns the character after
 *           the last character used in the conversion.
 *
 * Converts a string to a #gdouble value.
 *
 * This function behaves like the standard strtod() function
 * does in the C locale. It does this without actually changing
 * the current locale, since that would not be thread-safe.
 * A limitation of the implementation is that this function
 * will still accept localized versions of infinities and NANs.
 *
 * This function is typically used when reading configuration
 * files or other non-user input that should be locale independent.
 * To handle input from the user you should normally use the
 * locale-sensitive system strtod() function.
 *
 * To convert from a #gdouble to a string in a locale-insensitive
 * way, use g_ascii_dtostr().
 *
 * If the correct value would cause overflow, plus or minus <literal>HUGE_VAL</literal>
 * is returned (according to the sign of the value), and <literal>ERANGE</literal> is
 * stored in <literal>errno</literal>. If the correct value would cause underflow,
 * zero is returned and <literal>ERANGE</literal> is stored in <literal>errno</literal>.
 *
 * This function resets <literal>errno</literal> before calling strtod() so that
 * you can reliably detect overflow and underflow.
 *
 * Return value: the #gdouble value.
 */
gdouble
g_ascii_strtod (const gchar *nptr,
                gchar      **endptr)
{
#ifdef USE_XLOCALE

  g_return_val_if_fail (nptr != NULL, 0);

  errno = 0;

  return strtod_l (nptr, endptr, get_C_locale ());

#else

  gchar *fail_pos;
  gdouble val;
#ifndef __BIONIC__
  struct lconv *locale_data;
#endif
  const char *decimal_point;
  int decimal_point_len;
  const char *p, *decimal_point_pos;
  const char *end = NULL; /* Silence gcc */
  int strtod_errno;

  g_return_val_if_fail (nptr != NULL, 0);

  fail_pos = NULL;

#ifndef __BIONIC__
  locale_data = localeconv ();
  decimal_point = locale_data->decimal_point;
  decimal_point_len = strlen (decimal_point);
#else
  decimal_point = ".";
  decimal_point_len = 1;
#endif

  g_assert (decimal_point_len != 0);

  decimal_point_pos = NULL;
  end = NULL;

  if (decimal_point[0] != '.' ||
      decimal_point[1] != 0)
    {
      p = nptr;
      /* Skip leading space */
      while (g_ascii_isspace (*p))
        p++;

      /* Skip leading optional sign */
      if (*p == '+' || *p == '-')
        p++;

      if (p[0] == '0' &&
          (p[1] == 'x' || p[1] == 'X'))
        {
          p += 2;
          /* HEX - find the (optional) decimal point */

          while (g_ascii_isxdigit (*p))
            p++;

          if (*p == '.')
            decimal_point_pos = p++;

          while (g_ascii_isxdigit (*p))
            p++;

          if (*p == 'p' || *p == 'P')
            p++;
          if (*p == '+' || *p == '-')
            p++;
          while (g_ascii_isdigit (*p))
            p++;

          end = p;
        }
      else if (g_ascii_isdigit (*p) || *p == '.')
        {
          while (g_ascii_isdigit (*p))
            p++;

          if (*p == '.')
            decimal_point_pos = p++;

          while (g_ascii_isdigit (*p))
            p++;

          if (*p == 'e' || *p == 'E')
            p++;
          if (*p == '+' || *p == '-')
            p++;
          while (g_ascii_isdigit (*p))
            p++;

          end = p;
        }
      /* For the other cases, we need not convert the decimal point */
    }

  if (decimal_point_pos)
    {
      char *copy, *c;

      /* We need to convert the '.' to the locale specific decimal point */
      copy = g_malloc (end - nptr + 1 + decimal_point_len);

      c = copy;
      memcpy (c, nptr, decimal_point_pos - nptr);
      c += decimal_point_pos - nptr;
      memcpy (c, decimal_point, decimal_point_len);
      c += decimal_point_len;
      memcpy (c, decimal_point_pos + 1, end - (decimal_point_pos + 1));
      c += end - (decimal_point_pos + 1);
      *c = 0;

      errno = 0;
      val = strtod (copy, &fail_pos);
      strtod_errno = errno;

      if (fail_pos)
        {
          if (fail_pos - copy > decimal_point_pos - nptr)
            fail_pos = (char *)nptr + (fail_pos - copy) - (decimal_point_len - 1);
          else
            fail_pos = (char *)nptr + (fail_pos - copy);
        }

      g_free (copy);

    }
  else if (end)
    {
      char *copy;

      copy = g_malloc (end - (char *)nptr + 1);
      memcpy (copy, nptr, end - nptr);
      *(copy + (end - (char *)nptr)) = 0;

      errno = 0;
      val = strtod (copy, &fail_pos);
      strtod_errno = errno;

      if (fail_pos)
        {
          fail_pos = (char *)nptr + (fail_pos - copy);
        }

      g_free (copy);
    }
  else
    {
      errno = 0;
      val = strtod (nptr, &fail_pos);
      strtod_errno = errno;
    }

  if (endptr)
    *endptr = fail_pos;

  errno = strtod_errno;

  return val;
#endif
}


/**
 * g_ascii_dtostr:
 * @buffer: A buffer to place the resulting string in
 * @buf_len: The length of the buffer.
 * @d: The #gdouble to convert
 *
 * Converts a #gdouble to a string, using the '.' as
 * decimal point.
 *
 * This functions generates enough precision that converting
 * the string back using g_ascii_strtod() gives the same machine-number
 * (on machines with IEEE compatible 64bit doubles). It is
 * guaranteed that the size of the resulting string will never
 * be larger than @G_ASCII_DTOSTR_BUF_SIZE bytes.
 *
 * Return value: The pointer to the buffer with the converted string.
 **/
gchar *
g_ascii_dtostr (gchar       *buffer,
                gint         buf_len,
                gdouble      d)
{
  return g_ascii_formatd (buffer, buf_len, "%.17g", d);
}

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"

/**
 * g_ascii_formatd:
 * @buffer: A buffer to place the resulting string in
 * @buf_len: The length of the buffer.
 * @format: The printf()-style format to use for the
 *          code to use for converting.
 * @d: The #gdouble to convert
 *
 * Converts a #gdouble to a string, using the '.' as
 * decimal point. To format the number you pass in
 * a printf()-style format string. Allowed conversion
 * specifiers are 'e', 'E', 'f', 'F', 'g' and 'G'.
 *
 * If you just want to want to serialize the value into a
 * string, use g_ascii_dtostr().
 *
 * Return value: The pointer to the buffer with the converted string.
 */
gchar *
g_ascii_formatd (gchar       *buffer,
                 gint         buf_len,
                 const gchar *format,
                 gdouble      d)
{
#ifdef USE_XLOCALE
  locale_t old_locale;

  old_locale = uselocale (get_C_locale ());
   _g_snprintf (buffer, buf_len, format, d);
  uselocale (old_locale);

  return buffer;
#else
#ifndef __BIONIC__
  struct lconv *locale_data;
#endif
  const char *decimal_point;
  int decimal_point_len;
  gchar *p;
  int rest_len;
  gchar format_char;

  g_return_val_if_fail (buffer != NULL, NULL);
  g_return_val_if_fail (format[0] == '%', NULL);
  g_return_val_if_fail (strpbrk (format + 1, "'l%") == NULL, NULL);

  format_char = format[strlen (format) - 1];

  g_return_val_if_fail (format_char == 'e' || format_char == 'E' ||
                        format_char == 'f' || format_char == 'F' ||
                        format_char == 'g' || format_char == 'G',
                        NULL);

  if (format[0] != '%')
    return NULL;

  if (strpbrk (format + 1, "'l%"))
    return NULL;

  if (!(format_char == 'e' || format_char == 'E' ||
        format_char == 'f' || format_char == 'F' ||
        format_char == 'g' || format_char == 'G'))
    return NULL;

  _g_snprintf (buffer, buf_len, format, d);

#ifndef __BIONIC__
  locale_data = localeconv ();
  decimal_point = locale_data->decimal_point;
  decimal_point_len = strlen (decimal_point);
#else
  decimal_point = ".";
  decimal_point_len = 1;
#endif

  g_assert (decimal_point_len != 0);

  if (decimal_point[0] != '.' ||
      decimal_point[1] != 0)
    {
      p = buffer;

      while (g_ascii_isspace (*p))
        p++;

      if (*p == '+' || *p == '-')
        p++;

      while (isdigit ((guchar)*p))
        p++;

      if (strncmp (p, decimal_point, decimal_point_len) == 0)
        {
          *p = '.';
          p++;
          if (decimal_point_len > 1)
            {
              rest_len = strlen (p + (decimal_point_len-1));
              memmove (p, p + (decimal_point_len-1), rest_len);
              p[rest_len] = 0;
            }
        }
    }

  return buffer;
#endif
}
#pragma GCC diagnostic pop

#define ISSPACE(c)              ((c) == ' ' || (c) == '\f' || (c) == '\n' || \
                                 (c) == '\r' || (c) == '\t' || (c) == '\v')
#define ISUPPER(c)              ((c) >= 'A' && (c) <= 'Z')
#define ISLOWER(c)              ((c) >= 'a' && (c) <= 'z')
#define ISALPHA(c)              (ISUPPER (c) || ISLOWER (c))
#define TOUPPER(c)              (ISLOWER (c) ? (c) - 'a' + 'A' : (c))
#define TOLOWER(c)              (ISUPPER (c) ? (c) - 'A' + 'a' : (c))

#ifndef USE_XLOCALE

static guint64
g_parse_long_long (const gchar  *nptr,
                   const gchar **endptr,
                   guint         base,
                   gboolean     *negative)
{
  /* this code is based on on the strtol(3) code from GNU libc released under
   * the GNU Lesser General Public License.
   *
   * Copyright (C) 1991,92,94,95,96,97,98,99,2000,01,02
   *        Free Software Foundation, Inc.
   */
  gboolean overflow;
  guint64 cutoff;
  guint64 cutlim;
  guint64 ui64;
  const gchar *s, *save;
  guchar c;

  g_return_val_if_fail (nptr != NULL, 0);

  *negative = FALSE;
  if (base == 1 || base > 36)
    {
      errno = EINVAL;
      if (endptr)
        *endptr = nptr;
      return 0;
    }

  save = s = nptr;

  /* Skip white space.  */
  while (ISSPACE (*s))
    ++s;

  if (G_UNLIKELY (!*s))
    goto noconv;

  /* Check for a sign.  */
  if (*s == '-')
    {
      *negative = TRUE;
      ++s;
    }
  else if (*s == '+')
    ++s;

  /* Recognize number prefix and if BASE is zero, figure it out ourselves.  */
  if (*s == '0')
    {
      if ((base == 0 || base == 16) && TOUPPER (s[1]) == 'X')
        {
          s += 2;
          base = 16;
        }
      else if (base == 0)
        base = 8;
    }
  else if (base == 0)
    base = 10;

  /* Save the pointer so we can check later if anything happened.  */
  save = s;
  cutoff = G_MAXUINT64 / base;
  cutlim = G_MAXUINT64 % base;

  overflow = FALSE;
  ui64 = 0;
  c = *s;
  for (; c; c = *++s)
    {
      if (c >= '0' && c <= '9')
        c -= '0';
      else if (ISALPHA (c))
        c = TOUPPER (c) - 'A' + 10;
      else
        break;
      if (c >= base)
        break;
      /* Check for overflow.  */
      if (ui64 > cutoff || (ui64 == cutoff && c > cutlim))
        overflow = TRUE;
      else
        {
          ui64 *= base;
          ui64 += c;
        }
    }

  /* Check if anything actually happened.  */
  if (s == save)
    goto noconv;

  /* Store in ENDPTR the address of one character
     past the last character we converted.  */
  if (endptr)
    *endptr = s;

  if (G_UNLIKELY (overflow))
    {
      errno = ERANGE;
      return G_MAXUINT64;
    }

  return ui64;

 noconv:
  /* We must handle a special case here: the base is 0 or 16 and the
     first two characters are '0' and 'x', but the rest are no
     hexadecimal digits.  This is no error case.  We return 0 and
     ENDPTR points to the `x`.  */
  if (endptr)
    {
      if (save - nptr >= 2 && TOUPPER (save[-1]) == 'X'
          && save[-2] == '0')
        *endptr = &save[-1];
      else
        /*  There was no number to convert.  */
        *endptr = nptr;
    }
  return 0;
}
#endif /* !USE_XLOCALE */

/**
 * g_ascii_strtoull:
 * @nptr:    the string to convert to a numeric value.
 * @endptr:  if non-%NULL, it returns the character after
 *           the last character used in the conversion.
 * @base:    to be used for the conversion, 2..36 or 0
 *
 * Converts a string to a #guint64 value.
 * This function behaves like the standard strtoull() function
 * does in the C locale. It does this without actually
 * changing the current locale, since that would not be
 * thread-safe.
 *
 * This function is typically used when reading configuration
 * files or other non-user input that should be locale independent.
 * To handle input from the user you should normally use the
 * locale-sensitive system strtoull() function.
 *
 * If the correct value would cause overflow, %G_MAXUINT64
 * is returned, and <literal>ERANGE</literal> is stored in <literal>errno</literal>.
 * If the base is outside the valid range, zero is returned, and
 * <literal>EINVAL</literal> is stored in <literal>errno</literal>.
 * If the string conversion fails, zero is returned, and @endptr returns
 * @nptr (if @endptr is non-%NULL).
 *
 * Return value: the #guint64 value or zero on error.
 *
 * Since: 2.2
 */
guint64
g_ascii_strtoull (const gchar *nptr,
                  gchar      **endptr,
                  guint        base)
{
#ifdef USE_XLOCALE
  return strtoull_l (nptr, endptr, base, get_C_locale ());
#else
  gboolean negative;
  guint64 result;

  result = g_parse_long_long (nptr, (const gchar **) endptr, base, &negative);

  /* Return the result of the appropriate sign.  */
  return negative ? -result : result;
#endif
}

/**
 * g_ascii_strtoll:
 * @nptr:    the string to convert to a numeric value.
 * @endptr:  if non-%NULL, it returns the character after
 *           the last character used in the conversion.
 * @base:    to be used for the conversion, 2..36 or 0
 *
 * Converts a string to a #gint64 value.
 * This function behaves like the standard strtoll() function
 * does in the C locale. It does this without actually
 * changing the current locale, since that would not be
 * thread-safe.
 *
 * This function is typically used when reading configuration
 * files or other non-user input that should be locale independent.
 * To handle input from the user you should normally use the
 * locale-sensitive system strtoll() function.
 *
 * If the correct value would cause overflow, %G_MAXINT64 or %G_MININT64
 * is returned, and <literal>ERANGE</literal> is stored in <literal>errno</literal>.
 * If the base is outside the valid range, zero is returned, and
 * <literal>EINVAL</literal> is stored in <literal>errno</literal>. If the
 * string conversion fails, zero is returned, and @endptr returns @nptr
 * (if @endptr is non-%NULL).
 *
 * Return value: the #gint64 value or zero on error.
 *
 * Since: 2.12
 */
gint64
g_ascii_strtoll (const gchar *nptr,
                 gchar      **endptr,
                 guint        base)
{
#ifdef USE_XLOCALE
  return strtoll_l (nptr, endptr, base, get_C_locale ());
#else
  gboolean negative;
  guint64 result;

  result = g_parse_long_long (nptr, (const gchar **) endptr, base, &negative);

  if (negative && result > (guint64) G_MININT64)
    {
      errno = ERANGE;
      return G_MININT64;
    }
  else if (!negative && result > (guint64) G_MAXINT64)
    {
      errno = ERANGE;
      return G_MAXINT64;
    }
  else if (negative)
    return - (gint64) result;
  else
    return (gint64) result;
#endif
}

/**
 * g_strerror:
 * @errnum: the system error number. See the standard C %errno
 *     documentation
 *
 * Returns a string corresponding to the given error code, e.g.
 * "no such process". You should use this function in preference to
 * strerror(), because it returns a string in UTF-8 encoding, and since
 * not all platforms support the strerror() function.
 *
 * Returns: a UTF-8 string describing the error code. If the error code
 *     is unknown, it returns "unknown error (&lt;code&gt;)".
 */
const gchar *
g_strerror (gint errnum)
{
  gchar buf[64];
  gchar *msg;
  gchar *tofree;
  const gchar *ret;
  gint saved_errno = errno;

  msg = tofree = NULL;

#ifdef HAVE_STRERROR
  msg = strerror (errnum);
  if (!g_get_charset (NULL))
    msg = tofree = g_locale_to_utf8 (msg, -1, NULL, NULL, NULL);
#endif

  if (!msg)
    {
      msg = buf;
      _g_sprintf (msg, "unknown error (%d)", errnum);
    }

  ret = g_intern_string (msg);
  g_free (tofree);
  errno = saved_errno;
  return ret;
}

/**
 * g_strsignal:
 * @signum: the signal number. See the <literal>signal</literal>
 *     documentation
 *
 * Returns a string describing the given signal, e.g. "Segmentation fault".
 * You should use this function in preference to strsignal(), because it
 * returns a string in UTF-8 encoding, and since not all platforms support
 * the strsignal() function.
 *
 * Returns: a UTF-8 string describing the signal. If the signal is unknown,
 *     it returns "unknown signal (&lt;signum&gt;)".
 */
const gchar *
g_strsignal (gint signum)
{
  gchar *msg;
  gchar *tofree;
  const gchar *ret;

  msg = tofree = NULL;

#ifdef HAVE_STRSIGNAL
  msg = strsignal (signum);
  if (!g_get_charset (NULL))
    msg = tofree = g_locale_to_utf8 (msg, -1, NULL, NULL, NULL);
#endif

  if (!msg)
    msg = tofree = g_strdup_printf ("unknown signal (%d)", signum);
  ret = g_intern_string (msg);
  g_free (tofree);

  return ret;
}

/* Functions g_strlcpy and g_strlcat were originally developed by
 * Todd C. Miller <Todd.Miller@courtesan.com> to simplify writing secure code.
 * See http://www.openbsd.org/cgi-bin/man.cgi?query=strlcpy 
 * for more information.
 */

#ifdef HAVE_STRLCPY
/* Use the native ones, if available; they might be implemented in assembly */
gsize
g_strlcpy (gchar       *dest,
           const gchar *src,
           gsize        dest_size)
{
  g_return_val_if_fail (dest != NULL, 0);
  g_return_val_if_fail (src  != NULL, 0);

  return strlcpy (dest, src, dest_size);
}

gsize
g_strlcat (gchar       *dest,
           const gchar *src,
           gsize        dest_size)
{
  g_return_val_if_fail (dest != NULL, 0);
  g_return_val_if_fail (src  != NULL, 0);

  return strlcat (dest, src, dest_size);
}

#else /* ! HAVE_STRLCPY */
/**
 * g_strlcpy:
 * @dest: destination buffer
 * @src: source buffer
 * @dest_size: length of @dest in bytes
 *
 * Portability wrapper that calls strlcpy() on systems which have it,
 * and emulates strlcpy() otherwise. Copies @src to @dest; @dest is
 * guaranteed to be nul-terminated; @src must be nul-terminated;
 * @dest_size is the buffer size, not the number of chars to copy.
 *
 * At most dest_size - 1 characters will be copied. Always nul-terminates
 * (unless dest_size == 0). This function does <emphasis>not</emphasis>
 * allocate memory. Unlike strncpy(), this function doesn't pad dest (so
 * it's often faster). It returns the size of the attempted result,
 * strlen (src), so if @retval >= @dest_size, truncation occurred.
 *
 * <note><para>Caveat: strlcpy() is supposedly more secure than
 * strcpy() or strncpy(), but if you really want to avoid screwups,
 * g_strdup() is an even better idea.</para></note>
 *
 * Returns: length of @src
 */
gsize
g_strlcpy (gchar       *dest,
           const gchar *src,
           gsize        dest_size)
{
  register gchar *d = dest;
  register const gchar *s = src;
  register gsize n = dest_size;

  g_return_val_if_fail (dest != NULL, 0);
  g_return_val_if_fail (src  != NULL, 0);

  /* Copy as many bytes as will fit */
  if (n != 0 && --n != 0)
    do
      {
        register gchar c = *s++;

        *d++ = c;
        if (c == 0)
          break;
      }
    while (--n != 0);

  /* If not enough room in dest, add NUL and traverse rest of src */
  if (n == 0)
    {
      if (dest_size != 0)
        *d = 0;
      while (*s++)
        ;
    }

  return s - src - 1;  /* count does not include NUL */
}

/**
 * g_strlcat:
 * @dest: destination buffer, already containing one nul-terminated string
 * @src: source buffer
 * @dest_size: length of @dest buffer in bytes (not length of existing string
 *     inside @dest)
 *
 * Portability wrapper that calls strlcat() on systems which have it,
 * and emulates it otherwise. Appends nul-terminated @src string to @dest,
 * guaranteeing nul-termination for @dest. The total size of @dest won't
 * exceed @dest_size.
 *
 * At most dest_size - 1 characters will be copied.
 * Unlike strncat, dest_size is the full size of dest, not the space left over.
 * This function does NOT allocate memory.
 * This always NUL terminates (unless siz == 0 or there were no NUL characters
 * in the dest_size characters of dest to start with).
 *
 * <note><para>Caveat: this is supposedly a more secure alternative to
 * strcat() or strncat(), but for real security g_strconcat() is harder
 * to mess up.</para></note>
 *
 * Returns: size of attempted result, which is MIN (dest_size, strlen
 *          (original dest)) + strlen (src), so if retval >= dest_size,
 *          truncation occurred.
 **/
gsize
g_strlcat (gchar       *dest,
           const gchar *src,
           gsize        dest_size)
{
  register gchar *d = dest;
  register const gchar *s = src;
  register gsize bytes_left = dest_size;
  gsize dlength;  /* Logically, MIN (strlen (d), dest_size) */

  g_return_val_if_fail (dest != NULL, 0);
  g_return_val_if_fail (src  != NULL, 0);

  /* Find the end of dst and adjust bytes left but don't go past end */
  while (*d != 0 && bytes_left-- != 0)
    d++;
  dlength = d - dest;
  bytes_left = dest_size - dlength;

  if (bytes_left == 0)
    return dlength + strlen (s);

  while (*s != 0)
    {
      if (bytes_left != 1)
        {
          *d++ = *s;
          bytes_left--;
        }
      s++;
    }
  *d = 0;

  return dlength + (s - src);  /* count does not include NUL */
}
#endif /* ! HAVE_STRLCPY */

/**
 * g_ascii_strdown:
 * @str: a string.
 * @len: length of @str in bytes, or -1 if @str is nul-terminated.
 *
 * Converts all upper case ASCII letters to lower case ASCII letters.
 *
 * Return value: a newly-allocated string, with all the upper case
 *               characters in @str converted to lower case, with
 *               semantics that exactly match g_ascii_tolower(). (Note
 *               that this is unlike the old g_strdown(), which modified
 *               the string in place.)
 **/
gchar*
g_ascii_strdown (const gchar *str,
                 gssize       len)
{
  gchar *result, *s;

  g_return_val_if_fail (str != NULL, NULL);

  if (len < 0)
    len = strlen (str);

  result = g_strndup (str, len);
  for (s = result; *s; s++)
    *s = g_ascii_tolower (*s);

  return result;
}

/**
 * g_ascii_strup:
 * @str: a string.
 * @len: length of @str in bytes, or -1 if @str is nul-terminated.
 *
 * Converts all lower case ASCII letters to upper case ASCII letters.
 *
 * Return value: a newly allocated string, with all the lower case
 *               characters in @str converted to upper case, with
 *               semantics that exactly match g_ascii_toupper(). (Note
 *               that this is unlike the old g_strup(), which modified
 *               the string in place.)
 **/
gchar*
g_ascii_strup (const gchar *str,
               gssize       len)
{
  gchar *result, *s;

  g_return_val_if_fail (str != NULL, NULL);

  if (len < 0)
    len = strlen (str);

  result = g_strndup (str, len);
  for (s = result; *s; s++)
    *s = g_ascii_toupper (*s);

  return result;
}

/**
 * g_str_is_ascii:
 * @string: a string.
 *
 * Determines if a string is pure ASCII.  A string is pure ASCII if it
 * contains no bytes with the high bit set.
 *
 * Returns: %TRUE if @string is ascii
 *
 * Since: 2.40
 **/
gboolean
g_str_is_ascii (const gchar *string)
{
  gint i;

  for (i = 0; string[i]; i++)
    if (string[i] & 0x80)
      return FALSE;

  return TRUE;
}

/**
 * g_strdown:
 * @string: the string to convert.
 *
 * Converts a string to lower case.
 *
 * Return value: the string
 *
 * Deprecated:2.2: This function is totally broken for the reasons discussed
 * in the g_strncasecmp() docs - use g_ascii_strdown() or g_utf8_strdown()
 * instead.
 **/
gchar*
g_strdown (gchar *string)
{
  register guchar *s;

  g_return_val_if_fail (string != NULL, NULL);

  s = (guchar *) string;

  while (*s)
    {
      if (isupper (*s))
        *s = tolower (*s);
      s++;
    }

  return (gchar *) string;
}

/**
 * g_strup:
 * @string: the string to convert.
 *
 * Converts a string to upper case.
 *
 * Return value: the string
 *
 * Deprecated:2.2: This function is totally broken for the reasons discussed
 * in the g_strncasecmp() docs - use g_ascii_strup() or g_utf8_strup() instead.
 **/
gchar*
g_strup (gchar *string)
{
  register guchar *s;

  g_return_val_if_fail (string != NULL, NULL);

  s = (guchar *) string;

  while (*s)
    {
      if (islower (*s))
        *s = toupper (*s);
      s++;
    }

  return (gchar *) string;
}

/**
 * g_strreverse:
 * @string: the string to reverse
 *
 * Reverses all of the bytes in a string. For example,
 * <literal>g_strreverse ("abcdef")</literal> will result
 * in "fedcba".
 *
 * Note that g_strreverse() doesn't work on UTF-8 strings
 * containing multibyte characters. For that purpose, use
 * g_utf8_strreverse().
 *
 * Returns: the same pointer passed in as @string
 */
gchar*
g_strreverse (gchar *string)
{
  g_return_val_if_fail (string != NULL, NULL);

  if (*string)
    {
      register gchar *h, *t;

      h = string;
      t = string + strlen (string) - 1;

      while (h < t)
        {
          register gchar c;

          c = *h;
          *h = *t;
          h++;
          *t = c;
          t--;
        }
    }

  return string;
}

/**
 * g_ascii_tolower:
 * @c: any character.
 *
 * Convert a character to ASCII lower case.
 *
 * Unlike the standard C library tolower() function, this only
 * recognizes standard ASCII letters and ignores the locale, returning
 * all non-ASCII characters unchanged, even if they are lower case
 * letters in a particular character set. Also unlike the standard
 * library function, this takes and returns a char, not an int, so
 * don't call it on <literal>EOF</literal> but no need to worry about casting to #guchar
 * before passing a possibly non-ASCII character in.
 *
 * Return value: the result of converting @c to lower case.
 *               If @c is not an ASCII upper case letter,
 *               @c is returned unchanged.
 **/
gchar
g_ascii_tolower (gchar c)
{
  return g_ascii_isupper (c) ? c - 'A' + 'a' : c;
}

/**
 * g_ascii_toupper:
 * @c: any character.
 *
 * Convert a character to ASCII upper case.
 *
 * Unlike the standard C library toupper() function, this only
 * recognizes standard ASCII letters and ignores the locale, returning
 * all non-ASCII characters unchanged, even if they are upper case
 * letters in a particular character set. Also unlike the standard
 * library function, this takes and returns a char, not an int, so
 * don't call it on <literal>EOF</literal> but no need to worry about casting to #guchar
 * before passing a possibly non-ASCII character in.
 *
 * Return value: the result of converting @c to upper case.
 *               If @c is not an ASCII lower case letter,
 *               @c is returned unchanged.
 **/
gchar
g_ascii_toupper (gchar c)
{
  return g_ascii_islower (c) ? c - 'a' + 'A' : c;
}

/**
 * g_ascii_digit_value:
 * @c: an ASCII character.
 *
 * Determines the numeric value of a character as a decimal
 * digit. Differs from g_unichar_digit_value() because it takes
 * a char, so there's no worry about sign extension if characters
 * are signed.
 *
 * Return value: If @c is a decimal digit (according to
 * g_ascii_isdigit()), its numeric value. Otherwise, -1.
 **/
int
g_ascii_digit_value (gchar c)
{
  if (g_ascii_isdigit (c))
    return c - '0';
  return -1;
}

/**
 * g_ascii_xdigit_value:
 * @c: an ASCII character.
 *
 * Determines the numeric value of a character as a hexidecimal
 * digit. Differs from g_unichar_xdigit_value() because it takes
 * a char, so there's no worry about sign extension if characters
 * are signed.
 *
 * Return value: If @c is a hex digit (according to
 * g_ascii_isxdigit()), its numeric value. Otherwise, -1.
 **/
int
g_ascii_xdigit_value (gchar c)
{
  if (c >= 'A' && c <= 'F')
    return c - 'A' + 10;
  if (c >= 'a' && c <= 'f')
    return c - 'a' + 10;
  return g_ascii_digit_value (c);
}

/**
 * g_ascii_strcasecmp:
 * @s1: string to compare with @s2.
 * @s2: string to compare with @s1.
 *
 * Compare two strings, ignoring the case of ASCII characters.
 *
 * Unlike the BSD strcasecmp() function, this only recognizes standard
 * ASCII letters and ignores the locale, treating all non-ASCII
 * bytes as if they are not letters.
 *
 * This function should be used only on strings that are known to be
 * in encodings where the bytes corresponding to ASCII letters always
 * represent themselves. This includes UTF-8 and the ISO-8859-*
 * charsets, but not for instance double-byte encodings like the
 * Windows Codepage 932, where the trailing bytes of double-byte
 * characters include all ASCII letters. If you compare two CP932
 * strings using this function, you will get false matches.
 *
 * Return value: 0 if the strings match, a negative value if @s1 &lt; @s2,
 *   or a positive value if @s1 &gt; @s2.
 **/
gint
g_ascii_strcasecmp (const gchar *s1,
                    const gchar *s2)
{
  gint c1, c2;

  g_return_val_if_fail (s1 != NULL, 0);
  g_return_val_if_fail (s2 != NULL, 0);

  while (*s1 && *s2)
    {
      c1 = (gint)(guchar) TOLOWER (*s1);
      c2 = (gint)(guchar) TOLOWER (*s2);
      if (c1 != c2)
        return (c1 - c2);
      s1++; s2++;
    }

  return (((gint)(guchar) *s1) - ((gint)(guchar) *s2));
}

/**
 * g_ascii_strncasecmp:
 * @s1: string to compare with @s2.
 * @s2: string to compare with @s1.
 * @n:  number of characters to compare.
 *
 * Compare @s1 and @s2, ignoring the case of ASCII characters and any
 * characters after the first @n in each string.
 *
 * Unlike the BSD strcasecmp() function, this only recognizes standard
 * ASCII letters and ignores the locale, treating all non-ASCII
 * characters as if they are not letters.
 *
 * The same warning as in g_ascii_strcasecmp() applies: Use this
 * function only on strings known to be in encodings where bytes
 * corresponding to ASCII letters always represent themselves.
 *
 * Return value: 0 if the strings match, a negative value if @s1 &lt; @s2,
 *   or a positive value if @s1 &gt; @s2.
 **/
gint
g_ascii_strncasecmp (const gchar *s1,
                     const gchar *s2,
                     gsize n)
{
  gint c1, c2;

  g_return_val_if_fail (s1 != NULL, 0);
  g_return_val_if_fail (s2 != NULL, 0);

  while (n && *s1 && *s2)
    {
      n -= 1;
      c1 = (gint)(guchar) TOLOWER (*s1);
      c2 = (gint)(guchar) TOLOWER (*s2);
      if (c1 != c2)
        return (c1 - c2);
      s1++; s2++;
    }

  if (n)
    return (((gint) (guchar) *s1) - ((gint) (guchar) *s2));
  else
    return 0;
}

/**
 * g_strcasecmp:
 * @s1: a string.
 * @s2: a string to compare with @s1.
 *
 * A case-insensitive string comparison, corresponding to the standard
 * strcasecmp() function on platforms which support it.
 *
 * Return value: 0 if the strings match, a negative value if @s1 &lt; @s2,
 *   or a positive value if @s1 &gt; @s2.
 *
 * Deprecated:2.2: See g_strncasecmp() for a discussion of why this function
 *   is deprecated and how to replace it.
 **/
gint
g_strcasecmp (const gchar *s1,
              const gchar *s2)
{
#ifdef HAVE_STRCASECMP
  g_return_val_if_fail (s1 != NULL, 0);
  g_return_val_if_fail (s2 != NULL, 0);

  return strcasecmp (s1, s2);
#else
  gint c1, c2;

  g_return_val_if_fail (s1 != NULL, 0);
  g_return_val_if_fail (s2 != NULL, 0);

  while (*s1 && *s2)
    {
      /* According to A. Cox, some platforms have islower's that
       * don't work right on non-uppercase
       */
      c1 = isupper ((guchar)*s1) ? tolower ((guchar)*s1) : *s1;
      c2 = isupper ((guchar)*s2) ? tolower ((guchar)*s2) : *s2;
      if (c1 != c2)
        return (c1 - c2);
      s1++; s2++;
    }

  return (((gint)(guchar) *s1) - ((gint)(guchar) *s2));
#endif
}

/**
 * g_strncasecmp:
 * @s1: a string.
 * @s2: a string to compare with @s1.
 * @n: the maximum number of characters to compare.
 *
 * A case-insensitive string comparison, corresponding to the standard
 * strncasecmp() function on platforms which support it.
 * It is similar to g_strcasecmp() except it only compares the first @n
 * characters of the strings.
 *
 * Return value: 0 if the strings match, a negative value if @s1 &lt; @s2,
 *   or a positive value if @s1 &gt; @s2.
 *
 * Deprecated:2.2: The problem with g_strncasecmp() is that it does the
 * comparison by calling toupper()/tolower(). These functions are
 * locale-specific and operate on single bytes. However, it is impossible
 * to handle things correctly from an I18N standpoint by operating on
 * bytes, since characters may be multibyte. Thus g_strncasecmp() is
 * broken if your string is guaranteed to be ASCII, since it's
 * locale-sensitive, and it's broken if your string is localized, since
 * it doesn't work on many encodings at all, including UTF-8, EUC-JP,
 * etc.
 *
 * There are therefore two replacement techniques: g_ascii_strncasecmp(),
 * which only works on ASCII and is not locale-sensitive, and
 * g_utf8_casefold() followed by strcmp() on the resulting strings, which is
 * good for case-insensitive sorting of UTF-8.
 **/
gint
g_strncasecmp (const gchar *s1,
               const gchar *s2,
               guint n)
{
#ifdef HAVE_STRNCASECMP
  return strncasecmp (s1, s2, n);
#else
  gint c1, c2;

  g_return_val_if_fail (s1 != NULL, 0);
  g_return_val_if_fail (s2 != NULL, 0);

  while (n && *s1 && *s2)
    {
      n -= 1;
      /* According to A. Cox, some platforms have islower's that
       * don't work right on non-uppercase
       */
      c1 = isupper ((guchar)*s1) ? tolower ((guchar)*s1) : *s1;
      c2 = isupper ((guchar)*s2) ? tolower ((guchar)*s2) : *s2;
      if (c1 != c2)
        return (c1 - c2);
      s1++; s2++;
    }

  if (n)
    return (((gint) (guchar) *s1) - ((gint) (guchar) *s2));
  else
    return 0;
#endif
}

/**
 * g_strdelimit:
 * @string: the string to convert
 * @delimiters: (allow-none): a string containing the current delimiters, or %NULL
 *     to use the standard delimiters defined in #G_STR_DELIMITERS
 * @new_delimiter: the new delimiter character
 *
 * Converts any delimiter characters in @string to @new_delimiter.
 * Any characters in @string which are found in @delimiters are
 * changed to the @new_delimiter character. Modifies @string in place,
 * and returns @string itself, not a copy. The return value is to
 * allow nesting such as
 * |[
 *   g_ascii_strup (g_strdelimit (str, "abc", '?'))
 * ]|
 *
 * Returns: @string
 */
gchar *
g_strdelimit (gchar       *string,
              const gchar *delimiters,
              gchar        new_delim)
{
  register gchar *c;

  g_return_val_if_fail (string != NULL, NULL);

  if (!delimiters)
    delimiters = G_STR_DELIMITERS;

  for (c = string; *c; c++)
    {
      if (strchr (delimiters, *c))
        *c = new_delim;
    }

  return string;
}

/**
 * g_strcanon:
 * @string: a nul-terminated array of bytes
 * @valid_chars: bytes permitted in @string
 * @substitutor: replacement character for disallowed bytes
 *
 * For each character in @string, if the character is not in
 * @valid_chars, replaces the character with @substitutor.
 * Modifies @string in place, and return @string itself, not
 * a copy. The return value is to allow nesting such as
 * |[
 *   g_ascii_strup (g_strcanon (str, "abc", '?'))
 * ]|
 *
 * Returns: @string
 */
gchar *
g_strcanon (gchar       *string,
            const gchar *valid_chars,
            gchar        substitutor)
{
  register gchar *c;

  g_return_val_if_fail (string != NULL, NULL);
  g_return_val_if_fail (valid_chars != NULL, NULL);

  for (c = string; *c; c++)
    {
      if (!strchr (valid_chars, *c))
        *c = substitutor;
    }

  return string;
}

/**
 * g_strcompress:
 * @source: a string to compress
 *
 * Replaces all escaped characters with their one byte equivalent.
 *
 * This function does the reverse conversion of g_strescape().
 *
 * Returns: a newly-allocated copy of @source with all escaped
 *     character compressed
 */
gchar *
g_strcompress (const gchar *source)
{
  const gchar *p = source, *octal;
  gchar *dest;
  gchar *q;

  g_return_val_if_fail (source != NULL, NULL);

  dest = g_malloc (strlen (source) + 1);
  q = dest;

  while (*p)
    {
      if (*p == '\\')
        {
          p++;
          switch (*p)
            {
            case '\0':
              g_warning ("g_strcompress: trailing \\");
              goto out;
            case '0':  case '1':  case '2':  case '3':  case '4':
            case '5':  case '6':  case '7':
              *q = 0;
              octal = p;
              while ((p < octal + 3) && (*p >= '0') && (*p <= '7'))
                {
                  *q = (*q * 8) + (*p - '0');
                  p++;
                }
              q++;
              p--;
              break;
            case 'b':
              *q++ = '\b';
              break;
            case 'f':
              *q++ = '\f';
              break;
            case 'n':
              *q++ = '\n';
              break;
            case 'r':
              *q++ = '\r';
              break;
            case 't':
              *q++ = '\t';
              break;
            case 'v':
              *q++ = '\v';
              break;
            default:            /* Also handles \" and \\ */
              *q++ = *p;
              break;
            }
        }
      else
        *q++ = *p;
      p++;
    }
out:
  *q = 0;

  return dest;
}

/**
 * g_strescape:
 * @source: a string to escape
 * @exceptions: a string of characters not to escape in @source
 *
 * Escapes the special characters '\b', '\f', '\n', '\r', '\t', '\v', '\'
 * and '&quot;' in the string @source by inserting a '\' before
 * them. Additionally all characters in the range 0x01-0x1F (everything
 * below SPACE) and in the range 0x7F-0xFF (all non-ASCII chars) are
 * replaced with a '\' followed by their octal representation.
 * Characters supplied in @exceptions are not escaped.
 *
 * g_strcompress() does the reverse conversion.
 *
 * Returns: a newly-allocated copy of @source with certain
 *     characters escaped. See above.
 */
gchar *
g_strescape (const gchar *source,
             const gchar *exceptions)
{
  const guchar *p;
  gchar *dest;
  gchar *q;
  guchar excmap[256];

  g_return_val_if_fail (source != NULL, NULL);

  p = (guchar *) source;
  /* Each source byte needs maximally four destination chars (\777) */
  q = dest = g_malloc (strlen (source) * 4 + 1);

  memset (excmap, 0, 256);
  if (exceptions)
    {
      guchar *e = (guchar *) exceptions;

      while (*e)
        {
          excmap[*e] = 1;
          e++;
        }
    }

  while (*p)
    {
      if (excmap[*p])
        *q++ = *p;
      else
        {
          switch (*p)
            {
            case '\b':
              *q++ = '\\';
              *q++ = 'b';
              break;
            case '\f':
              *q++ = '\\';
              *q++ = 'f';
              break;
            case '\n':
              *q++ = '\\';
              *q++ = 'n';
              break;
            case '\r':
              *q++ = '\\';
              *q++ = 'r';
              break;
            case '\t':
              *q++ = '\\';
              *q++ = 't';
              break;
            case '\v':
              *q++ = '\\';
              *q++ = 'v';
              break;
            case '\\':
              *q++ = '\\';
              *q++ = '\\';
              break;
            case '"':
              *q++ = '\\';
              *q++ = '"';
              break;
            default:
              if ((*p < ' ') || (*p >= 0177))
                {
                  *q++ = '\\';
                  *q++ = '0' + (((*p) >> 6) & 07);
                  *q++ = '0' + (((*p) >> 3) & 07);
                  *q++ = '0' + ((*p) & 07);
                }
              else
                *q++ = *p;
              break;
            }
        }
      p++;
    }
  *q = 0;
  return dest;
}

/**
 * g_strchug:
 * @string: a string to remove the leading whitespace from
 *
 * Removes leading whitespace from a string, by moving the rest
 * of the characters forward.
 *
 * This function doesn't allocate or reallocate any memory;
 * it modifies @string in place. The pointer to @string is
 * returned to allow the nesting of functions.
 *
 * Also see g_strchomp() and g_strstrip().
 *
 * Returns: @string
 */
gchar *
g_strchug (gchar *string)
{
  guchar *start;

  g_return_val_if_fail (string != NULL, NULL);

  for (start = (guchar*) string; *start && g_ascii_isspace (*start); start++)
    ;

  g_memmove (string, start, strlen ((gchar *) start) + 1);

  return string;
}

/**
 * g_strchomp:
 * @string: a string to remove the trailing whitespace from
 *
 * Removes trailing whitespace from a string.
 *
 * This function doesn't allocate or reallocate any memory;
 * it modifies @string in place. The pointer to @string is
 * returned to allow the nesting of functions.
 *
 * Also see g_strchug() and g_strstrip().
 *
 * Returns: @string.
 */
gchar *
g_strchomp (gchar *string)
{
  gsize len;

  g_return_val_if_fail (string != NULL, NULL);

  len = strlen (string);
  while (len--)
    {
      if (g_ascii_isspace ((guchar) string[len]))
        string[len] = '\0';
      else
        break;
    }

  return string;
}

/**
 * g_strsplit:
 * @string: a string to split
 * @delimiter: a string which specifies the places at which to split
 *     the string. The delimiter is not included in any of the resulting
 *     strings, unless @max_tokens is reached.
 * @max_tokens: the maximum number of pieces to split @string into.
 *     If this is less than 1, the string is split completely.
 *
 * Splits a string into a maximum of @max_tokens pieces, using the given
 * @delimiter. If @max_tokens is reached, the remainder of @string is
 * appended to the last token.
 *
 * As a special case, the result of splitting the empty string "" is an empty
 * vector, not a vector containing a single string. The reason for this
 * special case is that being able to represent a empty vector is typically
 * more useful than consistent handling of empty elements. If you do need
 * to represent empty elements, you'll need to check for the empty string
 * before calling g_strsplit().
 *
 * Return value: a newly-allocated %NULL-terminated array of strings. Use
 *    g_strfreev() to free it.
 */
gchar**
g_strsplit (const gchar *string,
            const gchar *delimiter,
            gint         max_tokens)
{
  GSList *string_list = NULL, *slist;
  gchar **str_array, *s;
  guint n = 0;
  const gchar *remainder;

  g_return_val_if_fail (string != NULL, NULL);
  g_return_val_if_fail (delimiter != NULL, NULL);
  g_return_val_if_fail (delimiter[0] != '\0', NULL);

  if (max_tokens < 1)
    max_tokens = G_MAXINT;

  remainder = string;
  s = strstr (remainder, delimiter);
  if (s)
    {
      gsize delimiter_len = strlen (delimiter);

      while (--max_tokens && s)
        {
          gsize len;

          len = s - remainder;
          string_list = g_slist_prepend (string_list,
                                         g_strndup (remainder, len));
          n++;
          remainder = s + delimiter_len;
          s = strstr (remainder, delimiter);
        }
    }
  if (*string)
    {
      n++;
      string_list = g_slist_prepend (string_list, g_strdup (remainder));
    }

  str_array = g_new (gchar*, n + 1);

  str_array[n--] = NULL;
  for (slist = string_list; slist; slist = slist->next)
    str_array[n--] = slist->data;

  g_slist_free (string_list);

  return str_array;
}

/**
 * g_strsplit_set:
 * @string: The string to be tokenized
 * @delimiters: A nul-terminated string containing bytes that are used
 *     to split the string.
 * @max_tokens: The maximum number of tokens to split @string into.
 *     If this is less than 1, the string is split completely
 *
 * Splits @string into a number of tokens not containing any of the characters
 * in @delimiter. A token is the (possibly empty) longest string that does not
 * contain any of the characters in @delimiters. If @max_tokens is reached, the
 * remainder is appended to the last token.
 *
 * For example the result of g_strsplit_set ("abc:def/ghi", ":/", -1) is a
 * %NULL-terminated vector containing the three strings "abc", "def",
 * and "ghi".
 *
 * The result if g_strsplit_set (":def/ghi:", ":/", -1) is a %NULL-terminated
 * vector containing the four strings "", "def", "ghi", and "".
 *
 * As a special case, the result of splitting the empty string "" is an empty
 * vector, not a vector containing a single string. The reason for this
 * special case is that being able to represent a empty vector is typically
 * more useful than consistent handling of empty elements. If you do need
 * to represent empty elements, you'll need to check for the empty string
 * before calling g_strsplit_set().
 *
 * Note that this function works on bytes not characters, so it can't be used
 * to delimit UTF-8 strings for anything but ASCII characters.
 *
 * Return value: a newly-allocated %NULL-terminated array of strings. Use
 *    g_strfreev() to free it.
 *
 * Since: 2.4
 **/
gchar **
g_strsplit_set (const gchar *string,
                const gchar *delimiters,
                gint         max_tokens)
{
  gboolean delim_table[256];
  GSList *tokens, *list;
  gint n_tokens;
  const gchar *s;
  const gchar *current;
  gchar *token;
  gchar **result;

  g_return_val_if_fail (string != NULL, NULL);
  g_return_val_if_fail (delimiters != NULL, NULL);

  if (max_tokens < 1)
    max_tokens = G_MAXINT;

  if (*string == '\0')
    {
      result = g_new (char *, 1);
      result[0] = NULL;
      return result;
    }

  memset (delim_table, FALSE, sizeof (delim_table));
  for (s = delimiters; *s != '\0'; ++s)
    delim_table[*(guchar *)s] = TRUE;

  tokens = NULL;
  n_tokens = 0;

  s = current = string;
  while (*s != '\0')
    {
      if (delim_table[*(guchar *)s] && n_tokens + 1 < max_tokens)
        {
          token = g_strndup (current, s - current);
          tokens = g_slist_prepend (tokens, token);
          ++n_tokens;

          current = s + 1;
        }

      ++s;
    }

  token = g_strndup (current, s - current);
  tokens = g_slist_prepend (tokens, token);
  ++n_tokens;

  result = g_new (gchar *, n_tokens + 1);

  result[n_tokens] = NULL;
  for (list = tokens; list != NULL; list = list->next)
    result[--n_tokens] = list->data;

  g_slist_free (tokens);

  return result;
}

/**
 * g_strfreev:
 * @str_array: a %NULL-terminated array of strings to free

 * Frees a %NULL-terminated array of strings, and the array itself.
 * If called on a %NULL value, g_strfreev() simply returns.
 **/
void
g_strfreev (gchar **str_array)
{
  if (str_array)
    {
      int i;

      for (i = 0; str_array[i] != NULL; i++)
        g_free (str_array[i]);

      g_free (str_array);
    }
}

/**
 * g_strdupv:
 * @str_array: a %NULL-terminated array of strings
 *
 * Copies %NULL-terminated array of strings. The copy is a deep copy;
 * the new array should be freed by first freeing each string, then
 * the array itself. g_strfreev() does this for you. If called
 * on a %NULL value, g_strdupv() simply returns %NULL.
 *
 * Return value: a new %NULL-terminated array of strings.
 */
gchar**
g_strdupv (gchar **str_array)
{
  if (str_array)
    {
      gint i;
      gchar **retval;

      i = 0;
      while (str_array[i])
        ++i;

      retval = g_new (gchar*, i + 1);

      i = 0;
      while (str_array[i])
        {
          retval[i] = g_strdup (str_array[i]);
          ++i;
        }
      retval[i] = NULL;

      return retval;
    }
  else
    return NULL;
}

/**
 * g_strjoinv:
 * @separator: (allow-none): a string to insert between each of the strings, or %NULL
 * @str_array: a %NULL-terminated array of strings to join
 *
 * Joins a number of strings together to form one long string, with the
 * optional @separator inserted between each of them. The returned string
 * should be freed with g_free().
 *
 * Returns: a newly-allocated string containing all of the strings joined
 *     together, with @separator between them
 */
gchar*
g_strjoinv (const gchar  *separator,
            gchar       **str_array)
{
  gchar *string;
  gchar *ptr;

  g_return_val_if_fail (str_array != NULL, NULL);

  if (separator == NULL)
    separator = "";

  if (*str_array)
    {
      gint i;
      gsize len;
      gsize separator_len;

      separator_len = strlen (separator);
      /* First part, getting length */
      len = 1 + strlen (str_array[0]);
      for (i = 1; str_array[i] != NULL; i++)
        len += strlen (str_array[i]);
      len += separator_len * (i - 1);

      /* Second part, building string */
      string = g_new (gchar, len);
      ptr = g_stpcpy (string, *str_array);
      for (i = 1; str_array[i] != NULL; i++)
        {
          ptr = g_stpcpy (ptr, separator);
          ptr = g_stpcpy (ptr, str_array[i]);
        }
      }
  else
    string = g_strdup ("");

  return string;
}

/**
 * g_strjoin:
 * @separator: (allow-none): a string to insert between each of the strings, or %NULL
 * @...: a %NULL-terminated list of strings to join
 *
 * Joins a number of strings together to form one long string, with the
 * optional @separator inserted between each of them. The returned string
 * should be freed with g_free().
 *
 * Returns: a newly-allocated string containing all of the strings joined
 *     together, with @separator between them
 */
gchar*
g_strjoin (const gchar *separator,
           ...)
{
  gchar *string, *s;
  va_list args;
  gsize len;
  gsize separator_len;
  gchar *ptr;

  if (separator == NULL)
    separator = "";

  separator_len = strlen (separator);

  va_start (args, separator);

  s = va_arg (args, gchar*);

  if (s)
    {
      /* First part, getting length */
      len = 1 + strlen (s);

      s = va_arg (args, gchar*);
      while (s)
        {
          len += separator_len + strlen (s);
          s = va_arg (args, gchar*);
        }
      va_end (args);

      /* Second part, building string */
      string = g_new (gchar, len);

      va_start (args, separator);

      s = va_arg (args, gchar*);
      ptr = g_stpcpy (string, s);

      s = va_arg (args, gchar*);
      while (s)
        {
          ptr = g_stpcpy (ptr, separator);
          ptr = g_stpcpy (ptr, s);
          s = va_arg (args, gchar*);
        }
    }
  else
    string = g_strdup ("");

  va_end (args);

  return string;
}


/**
 * g_strstr_len:
 * @haystack: a string
 * @haystack_len: the maximum length of @haystack. Note that -1 is
 *     a valid length, if @haystack is nul-terminated, meaning it will
 *     search through the whole string.
 * @needle: the string to search for
 *
 * Searches the string @haystack for the first occurrence
 * of the string @needle, limiting the length of the search
 * to @haystack_len.
 *
 * Return value: a pointer to the found occurrence, or
 *    %NULL if not found.
 */
gchar *
g_strstr_len (const gchar *haystack,
              gssize       haystack_len,
              const gchar *needle)
{
  g_return_val_if_fail (haystack != NULL, NULL);
  g_return_val_if_fail (needle != NULL, NULL);

  if (haystack_len < 0)
    return strstr (haystack, needle);
  else
    {
      const gchar *p = haystack;
      gsize needle_len = strlen (needle);
      const gchar *end;
      gsize i;

      if (needle_len == 0)
        return (gchar *)haystack;

      if (haystack_len < needle_len)
        return NULL;

      end = haystack + haystack_len - needle_len;

      while (p <= end && *p)
        {
          for (i = 0; i < needle_len; i++)
            if (p[i] != needle[i])
              goto next;

          return (gchar *)p;

        next:
          p++;
        }

      return NULL;
    }
}

/**
 * g_strrstr:
 * @haystack: a nul-terminated string
 * @needle: the nul-terminated string to search for
 *
 * Searches the string @haystack for the last occurrence
 * of the string @needle.
 *
 * Return value: a pointer to the found occurrence, or
 *    %NULL if not found.
 */
gchar *
g_strrstr (const gchar *haystack,
           const gchar *needle)
{
  gsize i;
  gsize needle_len;
  gsize haystack_len;
  const gchar *p;

  g_return_val_if_fail (haystack != NULL, NULL);
  g_return_val_if_fail (needle != NULL, NULL);

  needle_len = strlen (needle);
  haystack_len = strlen (haystack);

  if (needle_len == 0)
    return (gchar *)haystack;

  if (haystack_len < needle_len)
    return NULL;

  p = haystack + haystack_len - needle_len;

  while (p >= haystack)
    {
      for (i = 0; i < needle_len; i++)
        if (p[i] != needle[i])
          goto next;

      return (gchar *)p;

    next:
      p--;
    }

  return NULL;
}

/**
 * g_strrstr_len:
 * @haystack: a nul-terminated string
 * @haystack_len: the maximum length of @haystack
 * @needle: the nul-terminated string to search for
 *
 * Searches the string @haystack for the last occurrence
 * of the string @needle, limiting the length of the search
 * to @haystack_len.
 *
 * Return value: a pointer to the found occurrence, or
 *    %NULL if not found.
 */
gchar *
g_strrstr_len (const gchar *haystack,
               gssize        haystack_len,
               const gchar *needle)
{
  g_return_val_if_fail (haystack != NULL, NULL);
  g_return_val_if_fail (needle != NULL, NULL);

  if (haystack_len < 0)
    return g_strrstr (haystack, needle);
  else
    {
      gsize needle_len = strlen (needle);
      const gchar *haystack_max = haystack + haystack_len;
      const gchar *p = haystack;
      gsize i;

      while (p < haystack_max && *p)
        p++;

      if (p < haystack + needle_len)
        return NULL;

      p -= needle_len;

      while (p >= haystack)
        {
          for (i = 0; i < needle_len; i++)
            if (p[i] != needle[i])
              goto next;

          return (gchar *)p;

        next:
          p--;
        }

      return NULL;
    }
}


/**
 * g_str_has_suffix:
 * @str: a nul-terminated string
 * @suffix: the nul-terminated suffix to look for
 *
 * Looks whether the string @str ends with @suffix.
 *
 * Return value: %TRUE if @str end with @suffix, %FALSE otherwise.
 *
 * Since: 2.2
 */
gboolean
g_str_has_suffix (const gchar *str,
                  const gchar *suffix)
{
  int str_len;
  int suffix_len;

  g_return_val_if_fail (str != NULL, FALSE);
  g_return_val_if_fail (suffix != NULL, FALSE);

  str_len = strlen (str);
  suffix_len = strlen (suffix);

  if (str_len < suffix_len)
    return FALSE;

  return strcmp (str + str_len - suffix_len, suffix) == 0;
}

/**
 * g_str_has_prefix:
 * @str: a nul-terminated string
 * @prefix: the nul-terminated prefix to look for
 *
 * Looks whether the string @str begins with @prefix.
 *
 * Return value: %TRUE if @str begins with @prefix, %FALSE otherwise.
 *
 * Since: 2.2
 */
gboolean
g_str_has_prefix (const gchar *str,
                  const gchar *prefix)
{
  int str_len;
  int prefix_len;

  g_return_val_if_fail (str != NULL, FALSE);
  g_return_val_if_fail (prefix != NULL, FALSE);

  str_len = strlen (str);
  prefix_len = strlen (prefix);

  if (str_len < prefix_len)
    return FALSE;

  return strncmp (str, prefix, prefix_len) == 0;
}

/**
 * g_strv_length:
 * @str_array: a %NULL-terminated array of strings
 *
 * Returns the length of the given %NULL-terminated
 * string array @str_array.
 *
 * Return value: length of @str_array.
 *
 * Since: 2.6
 */
guint
g_strv_length (gchar **str_array)
{
  guint i = 0;

  g_return_val_if_fail (str_array != NULL, 0);

  while (str_array[i])
    ++i;

  return i;
}

static void
index_add_folded (GPtrArray   *array,
                  const gchar *start,
                  const gchar *end)
{
  gchar *normal;

  normal = g_utf8_normalize (start, end - start, G_NORMALIZE_ALL_COMPOSE);

  /* TODO: Invent time machine.  Converse with Mustafa Ataturk... */
  if (strstr (normal, "ı") || strstr (normal, "İ"))
    {
      gchar *s = normal;
      GString *tmp;

      tmp = g_string_new (NULL);

      while (*s)
        {
          gchar *i, *I, *e;

          i = strstr (s, "ı");
          I = strstr (s, "İ");

          if (!i && !I)
            break;
          else if (i && !I)
            e = i;
          else if (I && !i)
            e = I;
          else if (i < I)
            e = i;
          else
            e = I;

          g_string_append_len (tmp, s, e - s);
          g_string_append_c (tmp, 'i');
          s = g_utf8_next_char (e);
        }

      g_string_append (tmp, s);
      g_free (normal);
      normal = g_string_free (tmp, FALSE);
    }

  g_ptr_array_add (array, g_utf8_casefold (normal, -1));
  g_free (normal);
}

static gchar **
split_words (const gchar *value)
{
  const gchar *start = NULL;
  GPtrArray *result;
  const gchar *s;

  result = g_ptr_array_new ();

  for (s = value; *s; s = g_utf8_next_char (s))
    {
      gunichar c = g_utf8_get_char (s);

      if (start == NULL)
        {
          if (g_unichar_isalnum (c) || g_unichar_ismark (c))
            start = s;
        }
      else
        {
          if (!g_unichar_isalnum (c) && !g_unichar_ismark (c))
            {
              index_add_folded (result, start, s);
              start = NULL;
            }
        }
    }

  if (start)
    index_add_folded (result, start, s);

  g_ptr_array_add (result, NULL);

  return (gchar **) g_ptr_array_free (result, FALSE);
}

/**
 * g_str_tokenize_and_fold:
 * @string: a string
 * @translit_locale: (allow-none): the language code (like 'de' or
 *   'en_GB') from which @string originates
 * @ascii_alternates: (out) (transfer full) (array zero-terminated=1): a
 *   return location for ASCII alternates
 *
 * Tokenises @string and performs folding on each token.
 *
 * A token is a non-empty sequence of alphanumeric characters in the
 * source string, separated by non-alphanumeric characters.  An
 * "alphanumeric" character for this purpose is one that matches
 * g_unichar_isalnum() or g_unichar_ismark().
 *
 * Each token is then (Unicode) normalised and case-folded.  If
 * @ascii_alternates is non-%NULL and some of the returned tokens
 * contain non-ASCII characters, ASCII alternatives will be generated.
 *
 * The number of ASCII alternatives that are generated and the method
 * for doing so is unspecified, but @translit_locale (if specified) may
 * improve the transliteration if the language of the source string is
 * known.
 *
 * Returns: the folded tokens
 *
 * Since: 2.40
 **/
gchar **
g_str_tokenize_and_fold (const gchar   *string,
                         const gchar   *translit_locale,
                         gchar       ***ascii_alternates)
{
  gchar **result;

  if (ascii_alternates && g_str_is_ascii (string))
    {
      *ascii_alternates = g_new0 (gchar *, 0 + 1);
      ascii_alternates = NULL;
    }

  result = split_words (string);

  /* TODO: proper iconv transliteration (locale-dependent) */
  if (ascii_alternates)
    {
      gint i, j, n;

      n = g_strv_length (result);
      *ascii_alternates = g_new (gchar *, n + 1);
      j = 0;

      for (i = 0; i < n; i++)
        {
          if (!g_str_is_ascii (result[i]))
            {
              gchar *decomposed;
              gchar *ascii;
              gint k = 0;
              gint l = 0;

              decomposed = g_utf8_normalize (result[i], -1, G_NORMALIZE_ALL);
              ascii = g_malloc (strlen (decomposed) + 1);

              for (k = 0; decomposed[k]; k++)
                if (~decomposed[k] & 0x80)
                  ascii[l++] = decomposed[k];
              ascii[l] = '\0';

              (*ascii_alternates)[j++] = ascii;
              g_free (decomposed);
            }
        }

      (*ascii_alternates)[j] = NULL;
    }

  return result;
}

/**
 * g_str_match_string:
 * @search_term: the search term from the user
 * @potential_hit: the text that may be a hit
 * @accept_alternates: %TRUE to accept ASCII alternates
 *
 * Checks if a search conducted for @search_term should match
 * @potential_hit.
 *
 * This function calls g_str_tokenize_and_fold() on both
 * @search_term and @potential_hit.  ASCII alternates are never taken
 * for @search_term but will be taken for @potential_hit according to
 * the value of @accept_alternates.
 *
 * A hit occurs when each folded token in @search_term is a prefix of a
 * folded token from @potential_hit.
 *
 * Depending on how you're performing the search, it will typically be
 * faster to call g_str_tokenize_and_fold() on each string in
 * your corpus and build an index on the returned folded tokens, then
 * call g_str_tokenize_and_fold() on the search term and
 * perform lookups into that index.
 *
 * As some examples, searching for "fred" would match the potential hit
 * "Smith, Fred" and also "Frédéric".  Searching for "Fréd" would match
 * "Frédéric" but not "Frederic" (due to the one-directional nature of
 * accent matching).  Searching "fo" would match "Foo" and "Bar Foo
 * Baz", but not "SFO" (because no word as "fo" as a prefix).
 *
 * Returns: %TRUE if @potential_hit is a hit
 *
 * Since: 2.40
 **/
gboolean
g_str_match_string (const gchar *search_term,
                    const gchar *potential_hit,
                    gboolean     accept_alternates)
{
  gchar **alternates = NULL;
  gchar **term_tokens;
  gchar **hit_tokens;
  gboolean matched;
  gint i, j;

  term_tokens = g_str_tokenize_and_fold (search_term, NULL, NULL);
  hit_tokens = g_str_tokenize_and_fold (potential_hit, NULL, accept_alternates ? &alternates : NULL);

  matched = TRUE;

  for (i = 0; term_tokens[i]; i++)
    {
      for (j = 0; hit_tokens[j]; j++)
        if (g_str_has_prefix (hit_tokens[j], term_tokens[i]))
          goto one_matched;

      if (accept_alternates)
        for (j = 0; alternates[j]; j++)
          if (g_str_has_prefix (alternates[j], term_tokens[i]))
            goto one_matched;

      matched = FALSE;
      break;

one_matched:
      continue;
    }

  g_strfreev (term_tokens);
  g_strfreev (hit_tokens);
  g_strfreev (alternates);

  return matched;
}