glib inlined into SameTime

git-svn-id: http://svn.miranda-ng.org/main/trunk@8685 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 1902 insertions, 0 deletions

diff --git a/protocols/Sametime/src/glib/gutf8.c b/protocols/Sametime/src/glib/gutf8.c
new file mode 100644
index 0000000000..98f4707161
--- /dev/null
+++ b/protocols/Sametime/src/glib/gutf8.c
@@ -0,0 +1,1902 @@
+/* gutf8.c - Operations on UTF-8 strings.
+ *
+ * Copyright (C) 1999 Tom Tromey
+ * Copyright (C) 2000 Red Hat, 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 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 "config.h"
+
+#include <stdlib.h>
+#ifdef HAVE_CODESET
+#include <langinfo.h>
+#endif
+#include <string.h>
+
+#ifdef G_PLATFORM_WIN32
+#include <stdio.h>
+#define STRICT
+#include <windows.h>
+#undef STRICT
+#endif
+
+#include "libcharset/libcharset.h"
+
+#include "gconvert.h"
+#include "ghash.h"
+#include "gstrfuncs.h"
+#include "gtestutils.h"
+#include "gtypes.h"
+#include "gthread.h"
+#include "glibintl.h"
+
+#define UTF8_COMPUTE(Char, Mask, Len)					      \
+  if (Char < 128)							      \
+    {									      \
+      Len = 1;								      \
+      Mask = 0x7f;							      \
+    }									      \
+  else if ((Char & 0xe0) == 0xc0)					      \
+    {									      \
+      Len = 2;								      \
+      Mask = 0x1f;							      \
+    }									      \
+  else if ((Char & 0xf0) == 0xe0)					      \
+    {									      \
+      Len = 3;								      \
+      Mask = 0x0f;							      \
+    }									      \
+  else if ((Char & 0xf8) == 0xf0)					      \
+    {									      \
+      Len = 4;								      \
+      Mask = 0x07;							      \
+    }									      \
+  else if ((Char & 0xfc) == 0xf8)					      \
+    {									      \
+      Len = 5;								      \
+      Mask = 0x03;							      \
+    }									      \
+  else if ((Char & 0xfe) == 0xfc)					      \
+    {									      \
+      Len = 6;								      \
+      Mask = 0x01;							      \
+    }									      \
+  else									      \
+    Len = -1;
+
+#define UTF8_LENGTH(Char)              \
+  ((Char) < 0x80 ? 1 :                 \
+   ((Char) < 0x800 ? 2 :               \
+    ((Char) < 0x10000 ? 3 :            \
+     ((Char) < 0x200000 ? 4 :          \
+      ((Char) < 0x4000000 ? 5 : 6)))))
+   
+
+#define UTF8_GET(Result, Chars, Count, Mask, Len)			      \
+  (Result) = (Chars)[0] & (Mask);					      \
+  for ((Count) = 1; (Count) < (Len); ++(Count))				      \
+    {									      \
+      if (((Chars)[(Count)] & 0xc0) != 0x80)				      \
+	{								      \
+	  (Result) = -1;						      \
+	  break;							      \
+	}								      \
+      (Result) <<= 6;							      \
+      (Result) |= ((Chars)[(Count)] & 0x3f);				      \
+    }
+    
+/*
+ * Check whether a Unicode (5.2) char is in a valid range.
+ *
+ * The first check comes from the Unicode guarantee to never encode
+ * a point above 0x0010ffff, since UTF-16 couldn't represent it.
+ * 
+ * The second check covers surrogate pairs (category Cs).
+ * 
+ * The last two checks cover "Noncharacter": defined as:
+ *   "A code point that is permanently reserved for
+ *    internal use, and that should never be interchanged. In
+ *    Unicode 3.1, these consist of the values U+nFFFE and U+nFFFF
+ *    (where n is from 0 to 10_16) and the values U+FDD0..U+FDEF."
+ *
+ * @param Char the character
+ */
+#define UNICODE_VALID(Char)                   \
+    ((Char) < 0x110000 &&                     \
+     (((Char) & 0xFFFFF800) != 0xD800) &&     \
+     ((Char) < 0xFDD0 || (Char) > 0xFDEF) &&  \
+     ((Char) & 0xFFFE) != 0xFFFE)
+   
+     
+static const gchar utf8_skip_data[256] = {
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+  2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,6,6,1,1
+};
+
+const gchar * const g_utf8_skip = utf8_skip_data;
+
+/**
+ * g_utf8_find_prev_char:
+ * @str: pointer to the beginning of a UTF-8 encoded string
+ * @p: pointer to some position within @str
+ * 
+ * Given a position @p with a UTF-8 encoded string @str, find the start
+ * of the previous UTF-8 character starting before @p. Returns %NULL if no
+ * UTF-8 characters are present in @str before @p.
+ *
+ * @p does not have to be at the beginning of a UTF-8 character. No check
+ * is made to see if the character found is actually valid other than
+ * it starts with an appropriate byte.
+ *
+ * Return value: a pointer to the found character or %NULL.
+ **/
+gchar *
+g_utf8_find_prev_char (const char *str,
+		       const char *p)
+{
+  for (--p; p >= str; --p)
+    {
+      if ((*p & 0xc0) != 0x80)
+	return (gchar *)p;
+    }
+  return NULL;
+}
+
+/**
+ * g_utf8_find_next_char:
+ * @p: a pointer to a position within a UTF-8 encoded string
+ * @end: a pointer to the byte following the end of the string,
+ * or %NULL to indicate that the string is nul-terminated.
+ *
+ * Finds the start of the next UTF-8 character in the string after @p.
+ *
+ * @p does not have to be at the beginning of a UTF-8 character. No check
+ * is made to see if the character found is actually valid other than
+ * it starts with an appropriate byte.
+ * 
+ * Return value: a pointer to the found character or %NULL
+ **/
+gchar *
+g_utf8_find_next_char (const gchar *p,
+		       const gchar *end)
+{
+  if (*p)
+    {
+      if (end)
+	for (++p; p < end && (*p & 0xc0) == 0x80; ++p)
+	  ;
+      else
+	for (++p; (*p & 0xc0) == 0x80; ++p)
+	  ;
+    }
+  return (p == end) ? NULL : (gchar *)p;
+}
+
+/**
+ * g_utf8_prev_char:
+ * @p: a pointer to a position within a UTF-8 encoded string
+ *
+ * Finds the previous UTF-8 character in the string before @p.
+ *
+ * @p does not have to be at the beginning of a UTF-8 character. No check
+ * is made to see if the character found is actually valid other than
+ * it starts with an appropriate byte. If @p might be the first
+ * character of the string, you must use g_utf8_find_prev_char() instead.
+ * 
+ * Return value: a pointer to the found character.
+ **/
+gchar *
+g_utf8_prev_char (const gchar *p)
+{
+  while (TRUE)
+    {
+      p--;
+      if ((*p & 0xc0) != 0x80)
+	return (gchar *)p;
+    }
+}
+
+/**
+ * g_utf8_strlen:
+ * @p: pointer to the start of a UTF-8 encoded string
+ * @max: the maximum number of bytes to examine. If @max
+ *       is less than 0, then the string is assumed to be
+ *       nul-terminated. If @max is 0, @p will not be examined and
+ *       may be %NULL.
+ *
+ * Computes the length of the string in characters, not including
+ * the terminating nul character.
+ *
+ * Return value: the length of the string in characters
+ **/
+glong
+g_utf8_strlen (const gchar *p,
+               gssize       max)
+{
+  glong len = 0;
+  const gchar *start = p;
+  g_return_val_if_fail (p != NULL || max == 0, 0);
+
+  if (max < 0)
+    {
+      while (*p)
+        {
+          p = g_utf8_next_char (p);
+          ++len;
+        }
+    }
+  else
+    {
+      if (max == 0 || !*p)
+        return 0;
+
+      p = g_utf8_next_char (p);
+
+      while (p - start < max && *p)
+        {
+          ++len;
+          p = g_utf8_next_char (p);
+        }
+
+      /* only do the last len increment if we got a complete
+       * char (don't count partial chars)
+       */
+      if (p - start <= max)
+        ++len;
+    }
+
+  return len;
+}
+
+/**
+ * g_utf8_get_char:
+ * @p: a pointer to Unicode character encoded as UTF-8
+ * 
+ * Converts a sequence of bytes encoded as UTF-8 to a Unicode character.
+ * If @p does not point to a valid UTF-8 encoded character, results are
+ * undefined. If you are not sure that the bytes are complete
+ * valid Unicode characters, you should use g_utf8_get_char_validated()
+ * instead.
+ * 
+ * Return value: the resulting character
+ **/
+gunichar
+g_utf8_get_char (const gchar *p)
+{
+  int i, mask = 0, len;
+  gunichar result;
+  unsigned char c = (unsigned char) *p;
+
+  UTF8_COMPUTE (c, mask, len);
+  if (len == -1)
+    return (gunichar)-1;
+  UTF8_GET (result, p, i, mask, len);
+
+  return result;
+}
+
+/**
+ * g_utf8_offset_to_pointer:
+ * @str: a UTF-8 encoded string
+ * @offset: a character offset within @str
+ *
+ * Converts from an integer character offset to a pointer to a position
+ * within the string.
+ *
+ * Since 2.10, this function allows to pass a negative @offset to
+ * step backwards. It is usually worth stepping backwards from the end
+ * instead of forwards if @offset is in the last fourth of the string,
+ * since moving forward is about 3 times faster than moving backward.
+ *
+ * <note><para>
+ * This function doesn't abort when reaching the end of @str. Therefore
+ * you should be sure that @offset is within string boundaries before
+ * calling that function. Call g_utf8_strlen() when unsure.
+ *
+ * This limitation exists as this function is called frequently during
+ * text rendering and therefore has to be as fast as possible.
+ * </para></note>
+ *
+ * Return value: the resulting pointer
+ **/
+gchar *
+g_utf8_offset_to_pointer  (const gchar *str,
+			   glong        offset)
+{
+  const gchar *s = str;
+
+  if (offset > 0) 
+    while (offset--)
+      s = g_utf8_next_char (s);
+  else
+    {
+      const char *s1;
+
+      /* This nice technique for fast backwards stepping 
+       * through a UTF-8 string was dubbed "stutter stepping" 
+       * by its inventor, Larry Ewing.
+       */
+      while (offset)
+	{
+	  s1 = s;
+	  s += offset;
+	  while ((*s & 0xc0) == 0x80)
+	    s--;
+
+	  offset += g_utf8_pointer_to_offset (s, s1);
+	}
+    }
+
+  return (gchar *)s;
+}
+
+/**
+ * g_utf8_pointer_to_offset:
+ * @str: a UTF-8 encoded string
+ * @pos: a pointer to a position within @str
+ * 
+ * Converts from a pointer to position within a string to a integer
+ * character offset.
+ *
+ * Since 2.10, this function allows @pos to be before @str, and returns
+ * a negative offset in this case.
+ * 
+ * Return value: the resulting character offset
+ **/
+glong    
+g_utf8_pointer_to_offset (const gchar *str,
+			  const gchar *pos)
+{
+  const gchar *s = str;
+  glong offset = 0;    
+
+  if (pos < str) 
+    offset = - g_utf8_pointer_to_offset (pos, str);
+  else
+    while (s < pos)
+      {
+	s = g_utf8_next_char (s);
+	offset++;
+      }
+  
+  return offset;
+}
+
+
+/**
+ * g_utf8_strncpy:
+ * @dest: buffer to fill with characters from @src
+ * @src: UTF-8 encoded string
+ * @n: character count
+ * 
+ * Like the standard C strncpy() function, but 
+ * copies a given number of characters instead of a given number of 
+ * bytes. The @src string must be valid UTF-8 encoded text. 
+ * (Use g_utf8_validate() on all text before trying to use UTF-8 
+ * utility functions with it.)
+ * 
+ * Return value: @dest
+ **/
+gchar *
+g_utf8_strncpy (gchar       *dest,
+		const gchar *src,
+		gsize        n)
+{
+  const gchar *s = src;
+  while (n && *s)
+    {
+      s = g_utf8_next_char(s);
+      n--;
+    }
+  strncpy(dest, src, s - src);
+  dest[s - src] = 0;
+  return dest;
+}
+
+G_LOCK_DEFINE_STATIC (aliases);
+
+static GHashTable *
+get_alias_hash (void)
+{
+  static GHashTable *alias_hash = NULL;
+  const char *aliases;
+
+  G_LOCK (aliases);
+
+  if (!alias_hash)
+    {
+      alias_hash = g_hash_table_new (g_str_hash, g_str_equal);
+      
+      aliases = _g_locale_get_charset_aliases ();
+      while (*aliases != '\0')
+	{
+	  const char *canonical;
+	  const char *alias;
+	  const char **alias_array;
+	  int count = 0;
+	  
+	  alias = aliases;
+	  aliases += strlen (aliases) + 1;
+	  canonical = aliases;
+	  aliases += strlen (aliases) + 1;
+	  
+	  alias_array = g_hash_table_lookup (alias_hash, canonical);
+	  if (alias_array)
+	    {
+	      while (alias_array[count])
+		count++;
+	    }
+	  
+	  alias_array = g_renew (const char *, alias_array, count + 2);
+	  alias_array[count] = alias;
+	  alias_array[count + 1] = NULL;
+	  
+	  g_hash_table_insert (alias_hash, (char *)canonical, alias_array);
+	}
+    }
+
+  G_UNLOCK (aliases);
+
+  return alias_hash;
+}
+
+/* As an abuse of the alias table, the following routines gets
+ * the charsets that are aliases for the canonical name.
+ */
+G_GNUC_INTERNAL const char ** 
+_g_charset_get_aliases (const char *canonical_name)
+{
+  GHashTable *alias_hash = get_alias_hash ();
+
+  return g_hash_table_lookup (alias_hash, canonical_name);
+}
+
+static gboolean
+g_utf8_get_charset_internal (const char  *raw_data,
+			     const char **a)
+{
+  const char *charset = getenv("CHARSET");
+
+  if (charset && *charset)
+    {
+      *a = charset;
+
+      if (charset && strstr (charset, "UTF-8"))
+	return TRUE;
+      else
+	return FALSE;
+    }
+
+  /* The libcharset code tries to be thread-safe without
+   * a lock, but has a memory leak and a missing memory
+   * barrier, so we lock for it
+   */
+  G_LOCK (aliases);
+  charset = _g_locale_charset_unalias (raw_data);
+  G_UNLOCK (aliases);
+  
+  if (charset && *charset)
+    {
+      *a = charset;
+      
+      if (charset && strstr (charset, "UTF-8"))
+	return TRUE;
+      else
+	return FALSE;
+    }
+
+  /* Assume this for compatibility at present.  */
+  *a = "US-ASCII";
+  
+  return FALSE;
+}
+
+typedef struct _GCharsetCache GCharsetCache;
+
+struct _GCharsetCache {
+  gboolean is_utf8;
+  gchar *raw;
+  gchar *charset;
+};
+
+static void
+charset_cache_free (gpointer data)
+{
+  GCharsetCache *cache = data;
+  g_free (cache->raw);
+  g_free (cache->charset);
+  g_free (cache);
+}
+
+/**
+ * g_get_charset:
+ * @charset: return location for character set name
+ * 
+ * Obtains the character set for the <link linkend="setlocale">current 
+ * locale</link>; you might use this character set as an argument to 
+ * g_convert(), to convert from the current locale's encoding to some 
+ * other encoding. (Frequently g_locale_to_utf8() and g_locale_from_utf8()
+ * are nice shortcuts, though.)
+ *
+ * On Windows the character set returned by this function is the
+ * so-called system default ANSI code-page. That is the character set
+ * used by the "narrow" versions of C library and Win32 functions that
+ * handle file names. It might be different from the character set
+ * used by the C library's current locale.
+ *
+ * The return value is %TRUE if the locale's encoding is UTF-8, in that
+ * case you can perhaps avoid calling g_convert().
+ *
+ * The string returned in @charset is not allocated, and should not be
+ * freed.
+ * 
+ * Return value: %TRUE if the returned charset is UTF-8
+ **/
+gboolean
+g_get_charset (G_CONST_RETURN char **charset) 
+{
+  static GStaticPrivate cache_private = G_STATIC_PRIVATE_INIT;
+  GCharsetCache *cache = g_static_private_get (&cache_private);
+  const gchar *raw;
+
+  if (!cache)
+    {
+      cache = g_new0 (GCharsetCache, 1);
+      g_static_private_set (&cache_private, cache, charset_cache_free);
+    }
+
+  raw = _g_locale_charset_raw ();
+  
+  if (!(cache->raw && strcmp (cache->raw, raw) == 0))
+    {
+      const gchar *new_charset;
+	    
+      g_free (cache->raw);
+      g_free (cache->charset);
+      cache->raw = g_strdup (raw);
+      cache->is_utf8 = g_utf8_get_charset_internal (raw, &new_charset);
+      cache->charset = g_strdup (new_charset);
+    }
+
+  if (charset)
+    *charset = cache->charset;
+  
+  return cache->is_utf8;
+}
+
+/* unicode_strchr */
+
+/**
+ * g_unichar_to_utf8:
+ * @c: a Unicode character code
+ * @outbuf: output buffer, must have at least 6 bytes of space.
+ *       If %NULL, the length will be computed and returned
+ *       and nothing will be written to @outbuf.
+ * 
+ * Converts a single character to UTF-8.
+ * 
+ * Return value: number of bytes written
+ **/
+int
+g_unichar_to_utf8 (gunichar c,
+		   gchar   *outbuf)
+{
+  /* If this gets modified, also update the copy in g_string_insert_unichar() */
+  guint len = 0;    
+  int first;
+  int i;
+
+  if (c < 0x80)
+    {
+      first = 0;
+      len = 1;
+    }
+  else if (c < 0x800)
+    {
+      first = 0xc0;
+      len = 2;
+    }
+  else if (c < 0x10000)
+    {
+      first = 0xe0;
+      len = 3;
+    }
+   else if (c < 0x200000)
+    {
+      first = 0xf0;
+      len = 4;
+    }
+  else if (c < 0x4000000)
+    {
+      first = 0xf8;
+      len = 5;
+    }
+  else
+    {
+      first = 0xfc;
+      len = 6;
+    }
+
+  if (outbuf)
+    {
+      for (i = len - 1; i > 0; --i)
+	{
+	  outbuf[i] = (c & 0x3f) | 0x80;
+	  c >>= 6;
+	}
+      outbuf[0] = c | first;
+    }
+
+  return len;
+}
+
+/**
+ * g_utf8_strchr:
+ * @p: a nul-terminated UTF-8 encoded string
+ * @len: the maximum length of @p
+ * @c: a Unicode character
+ * 
+ * Finds the leftmost occurrence of the given Unicode character
+ * in a UTF-8 encoded string, while limiting the search to @len bytes.
+ * If @len is -1, allow unbounded search.
+ * 
+ * Return value: %NULL if the string does not contain the character, 
+ *   otherwise, a pointer to the start of the leftmost occurrence of 
+ *   the character in the string.
+ **/
+gchar *
+g_utf8_strchr (const char *p,
+	       gssize      len,
+	       gunichar    c)
+{
+  gchar ch[10];
+
+  gint charlen = g_unichar_to_utf8 (c, ch);
+  ch[charlen] = '\0';
+  
+  return g_strstr_len (p, len, ch);
+}
+
+
+/**
+ * g_utf8_strrchr:
+ * @p: a nul-terminated UTF-8 encoded string
+ * @len: the maximum length of @p
+ * @c: a Unicode character
+ * 
+ * Find the rightmost occurrence of the given Unicode character
+ * in a UTF-8 encoded string, while limiting the search to @len bytes.
+ * If @len is -1, allow unbounded search.
+ * 
+ * Return value: %NULL if the string does not contain the character, 
+ *   otherwise, a pointer to the start of the rightmost occurrence of the 
+ *   character in the string.
+ **/
+gchar *
+g_utf8_strrchr (const char *p,
+		gssize      len,
+		gunichar    c)
+{
+  gchar ch[10];
+
+  gint charlen = g_unichar_to_utf8 (c, ch);
+  ch[charlen] = '\0';
+  
+  return g_strrstr_len (p, len, ch);
+}
+
+
+/* Like g_utf8_get_char, but take a maximum length
+ * and return (gunichar)-2 on incomplete trailing character;
+ * also check for malformed or overlong sequences
+ * and return (gunichar)-1 in this case.
+ */
+static inline gunichar
+g_utf8_get_char_extended (const  gchar *p,
+			  gssize max_len)
+{
+  guint i, len;
+  gunichar min_code;
+  gunichar wc = (guchar) *p;
+
+  if (wc < 0x80)
+    {
+      return wc;
+    }
+  else if (G_UNLIKELY (wc < 0xc0))
+    {
+      return (gunichar)-1;
+    }
+  else if (wc < 0xe0)
+    {
+      len = 2;
+      wc &= 0x1f;
+      min_code = 1 << 7;
+    }
+  else if (wc < 0xf0)
+    {
+      len = 3;
+      wc &= 0x0f;
+      min_code = 1 << 11;
+    }
+  else if (wc < 0xf8)
+    {
+      len = 4;
+      wc &= 0x07;
+      min_code = 1 << 16;
+    }
+  else if (wc < 0xfc)
+    {
+      len = 5;
+      wc &= 0x03;
+      min_code = 1 << 21;
+    }
+  else if (wc < 0xfe)
+    {
+      len = 6;
+      wc &= 0x01;
+      min_code = 1 << 26;
+    }
+  else
+    {
+      return (gunichar)-1;
+    }
+
+  if (G_UNLIKELY (max_len >= 0 && len > max_len))
+    {
+      for (i = 1; i < max_len; i++)
+	{
+	  if ((((guchar *)p)[i] & 0xc0) != 0x80)
+	    return (gunichar)-1;
+	}
+      return (gunichar)-2;
+    }
+
+  for (i = 1; i < len; ++i)
+    {
+      gunichar ch = ((guchar *)p)[i];
+
+      if (G_UNLIKELY ((ch & 0xc0) != 0x80))
+	{
+	  if (ch)
+	    return (gunichar)-1;
+	  else
+	    return (gunichar)-2;
+	}
+
+      wc <<= 6;
+      wc |= (ch & 0x3f);
+    }
+
+  if (G_UNLIKELY (wc < min_code))
+    return (gunichar)-1;
+
+  return wc;
+}
+
+/**
+ * g_utf8_get_char_validated:
+ * @p: a pointer to Unicode character encoded as UTF-8
+ * @max_len: the maximum number of bytes to read, or -1, for no maximum or
+ *           if @p is nul-terminated
+ * 
+ * Convert a sequence of bytes encoded as UTF-8 to a Unicode character.
+ * This function checks for incomplete characters, for invalid characters
+ * such as characters that are out of the range of Unicode, and for
+ * overlong encodings of valid characters.
+ * 
+ * Return value: the resulting character. If @p points to a partial
+ *    sequence at the end of a string that could begin a valid 
+ *    character (or if @max_len is zero), returns (gunichar)-2; 
+ *    otherwise, if @p does not point to a valid UTF-8 encoded 
+ *    Unicode character, returns (gunichar)-1.
+ **/
+gunichar
+g_utf8_get_char_validated (const  gchar *p,
+			   gssize max_len)
+{
+  gunichar result;
+
+  if (max_len == 0)
+    return (gunichar)-2;
+
+  result = g_utf8_get_char_extended (p, max_len);
+
+  if (result & 0x80000000)
+    return result;
+  else if (!UNICODE_VALID (result))
+    return (gunichar)-1;
+  else
+    return result;
+}
+
+/**
+ * g_utf8_to_ucs4_fast:
+ * @str: a UTF-8 encoded string
+ * @len: the maximum length of @str to use, in bytes. If @len < 0,
+ *       then the string is nul-terminated.
+ * @items_written: location to store the number of characters in the
+ *                 result, or %NULL.
+ *
+ * Convert a string from UTF-8 to a 32-bit fixed width
+ * representation as UCS-4, assuming valid UTF-8 input.
+ * This function is roughly twice as fast as g_utf8_to_ucs4()
+ * but does no error checking on the input.
+ * 
+ * Return value: a pointer to a newly allocated UCS-4 string.
+ *               This value must be freed with g_free().
+ **/
+gunichar *
+g_utf8_to_ucs4_fast (const gchar *str,
+		     glong        len,              
+		     glong       *items_written)    
+{
+  gint j, charlen;
+  gunichar *result;
+  gint n_chars, i;
+  const gchar *p;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  p = str;
+  n_chars = 0;
+  if (len < 0)
+    {
+      while (*p)
+	{
+	  p = g_utf8_next_char (p);
+	  ++n_chars;
+	}
+    }
+  else
+    {
+      while (p < str + len && *p)
+	{
+	  p = g_utf8_next_char (p);
+	  ++n_chars;
+	}
+    }
+  
+  result = g_new (gunichar, n_chars + 1);
+  
+  p = str;
+  for (i=0; i < n_chars; i++)
+    {
+      gunichar wc = ((unsigned char *)p)[0];
+
+      if (wc < 0x80)
+	{
+	  result[i] = wc;
+	  p++;
+	}
+      else
+	{ 
+	  if (wc < 0xe0)
+	    {
+	      charlen = 2;
+	      wc &= 0x1f;
+	    }
+	  else if (wc < 0xf0)
+	    {
+	      charlen = 3;
+	      wc &= 0x0f;
+	    }
+	  else if (wc < 0xf8)
+	    {
+	      charlen = 4;
+	      wc &= 0x07;
+	    }
+	  else if (wc < 0xfc)
+	    {
+	      charlen = 5;
+	      wc &= 0x03;
+	    }
+	  else
+	    {
+	      charlen = 6;
+	      wc &= 0x01;
+	    }
+
+	  for (j = 1; j < charlen; j++)
+	    {
+	      wc <<= 6;
+	      wc |= ((unsigned char *)p)[j] & 0x3f;
+	    }
+
+	  result[i] = wc;
+	  p += charlen;
+	}
+    }
+  result[i] = 0;
+
+  if (items_written)
+    *items_written = i;
+
+  return result;
+}
+
+/**
+ * g_utf8_to_ucs4:
+ * @str: a UTF-8 encoded string
+ * @len: the maximum length of @str to use, in bytes. If @len < 0,
+ *       then the string is nul-terminated.
+ * @items_read: location to store number of bytes read, or %NULL.
+ *              If %NULL, then %G_CONVERT_ERROR_PARTIAL_INPUT will be
+ *              returned in case @str contains a trailing partial
+ *              character. If an error occurs then the index of the
+ *              invalid input is stored here.
+ * @items_written: location to store number of characters written or %NULL.
+ *                 The value here stored does not include the trailing 0
+ *                 character. 
+ * @error: location to store the error occuring, or %NULL to ignore
+ *         errors. Any of the errors in #GConvertError other than
+ *         %G_CONVERT_ERROR_NO_CONVERSION may occur.
+ *
+ * Convert a string from UTF-8 to a 32-bit fixed width
+ * representation as UCS-4. A trailing 0 will be added to the
+ * string after the converted text.
+ * 
+ * Return value: a pointer to a newly allocated UCS-4 string.
+ *               This value must be freed with g_free(). If an
+ *               error occurs, %NULL will be returned and
+ *               @error set.
+ **/
+gunichar *
+g_utf8_to_ucs4 (const gchar *str,
+		glong        len,             
+		glong       *items_read,      
+		glong       *items_written,   
+		GError     **error)
+{
+  gunichar *result = NULL;
+  gint n_chars, i;
+  const gchar *in;
+  
+  in = str;
+  n_chars = 0;
+  while ((len < 0 || str + len - in > 0) && *in)
+    {
+      gunichar wc = g_utf8_get_char_extended (in, len < 0 ? 6 : str + len - in);
+      if (wc & 0x80000000)
+	{
+	  if (wc == (gunichar)-2)
+	    {
+	      if (items_read)
+		break;
+	      else
+		g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_PARTIAL_INPUT,
+                                     _("Partial character sequence at end of input"));
+	    }
+	  else
+	    g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                                 _("Invalid byte sequence in conversion input"));
+
+	  goto err_out;
+	}
+
+      n_chars++;
+
+      in = g_utf8_next_char (in);
+    }
+
+  result = g_new (gunichar, n_chars + 1);
+  
+  in = str;
+  for (i=0; i < n_chars; i++)
+    {
+      result[i] = g_utf8_get_char (in);
+      in = g_utf8_next_char (in);
+    }
+  result[i] = 0;
+
+  if (items_written)
+    *items_written = n_chars;
+
+ err_out:
+  if (items_read)
+    *items_read = in - str;
+
+  return result;
+}
+
+/**
+ * g_ucs4_to_utf8:
+ * @str: a UCS-4 encoded string
+ * @len: the maximum length (number of characters) of @str to use. 
+ *       If @len < 0, then the string is nul-terminated.
+ * @items_read: location to store number of characters read, or %NULL.
+ * @items_written: location to store number of bytes written or %NULL.
+ *                 The value here stored does not include the trailing 0
+ *                 byte. 
+ * @error: location to store the error occuring, or %NULL to ignore
+ *         errors. Any of the errors in #GConvertError other than
+ *         %G_CONVERT_ERROR_NO_CONVERSION may occur.
+ *
+ * Convert a string from a 32-bit fixed width representation as UCS-4.
+ * to UTF-8. The result will be terminated with a 0 byte.
+ * 
+ * Return value: a pointer to a newly allocated UTF-8 string.
+ *               This value must be freed with g_free(). If an
+ *               error occurs, %NULL will be returned and
+ *               @error set. In that case, @items_read will be
+ *               set to the position of the first invalid input 
+ *               character.
+ **/
+gchar *
+g_ucs4_to_utf8 (const gunichar *str,
+		glong           len,              
+		glong          *items_read,       
+		glong          *items_written,    
+		GError        **error)
+{
+  gint result_length;
+  gchar *result = NULL;
+  gchar *p;
+  gint i;
+
+  result_length = 0;
+  for (i = 0; len < 0 || i < len ; i++)
+    {
+      if (!str[i])
+	break;
+
+      if (str[i] >= 0x80000000)
+	{
+	  g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                               _("Character out of range for UTF-8"));
+	  goto err_out;
+	}
+      
+      result_length += UTF8_LENGTH (str[i]);
+    }
+
+  result = g_malloc (result_length + 1);
+  p = result;
+
+  i = 0;
+  while (p < result + result_length)
+    p += g_unichar_to_utf8 (str[i++], p);
+  
+  *p = '\0';
+
+  if (items_written)
+    *items_written = p - result;
+
+ err_out:
+  if (items_read)
+    *items_read = i;
+
+  return result;
+}
+
+#define SURROGATE_VALUE(h,l) (((h) - 0xd800) * 0x400 + (l) - 0xdc00 + 0x10000)
+
+/**
+ * g_utf16_to_utf8:
+ * @str: a UTF-16 encoded string
+ * @len: the maximum length (number of <type>gunichar2</type>) of @str to use. 
+ *       If @len < 0, then the string is nul-terminated.
+ * @items_read: location to store number of words read, or %NULL.
+ *              If %NULL, then %G_CONVERT_ERROR_PARTIAL_INPUT will be
+ *              returned in case @str contains a trailing partial
+ *              character. If an error occurs then the index of the
+ *              invalid input is stored here.
+ * @items_written: location to store number of bytes written, or %NULL.
+ *                 The value stored here does not include the trailing
+ *                 0 byte.
+ * @error: location to store the error occuring, or %NULL to ignore
+ *         errors. Any of the errors in #GConvertError other than
+ *         %G_CONVERT_ERROR_NO_CONVERSION may occur.
+ *
+ * Convert a string from UTF-16 to UTF-8. The result will be
+ * terminated with a 0 byte.
+ *
+ * Note that the input is expected to be already in native endianness,
+ * an initial byte-order-mark character is not handled specially.
+ * g_convert() can be used to convert a byte buffer of UTF-16 data of
+ * ambiguous endianess.
+ *
+ * Further note that this function does not validate the result
+ * string; it may e.g. include embedded NUL characters. The only
+ * validation done by this function is to ensure that the input can
+ * be correctly interpreted as UTF-16, i.e. it doesn't contain
+ * things unpaired surrogates.
+ *
+ * Return value: a pointer to a newly allocated UTF-8 string.
+ *               This value must be freed with g_free(). If an
+ *               error occurs, %NULL will be returned and
+ *               @error set.
+ **/
+gchar *
+g_utf16_to_utf8 (const gunichar2  *str,
+		 glong             len,
+		 glong            *items_read,
+		 glong            *items_written,
+		 GError          **error)
+{
+  /* This function and g_utf16_to_ucs4 are almost exactly identical - The lines that differ
+   * are marked.
+   */
+  const gunichar2 *in;
+  gchar *out;
+  gchar *result = NULL;
+  gint n_bytes;
+  gunichar high_surrogate;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  n_bytes = 0;
+  in = str;
+  high_surrogate = 0;
+  while ((len < 0 || in - str < len) && *in)
+    {
+      gunichar2 c = *in;
+      gunichar wc;
+
+      if (c >= 0xdc00 && c < 0xe000) /* low surrogate */
+	{
+	  if (high_surrogate)
+	    {
+	      wc = SURROGATE_VALUE (high_surrogate, c);
+	      high_surrogate = 0;
+	    }
+	  else
+	    {
+	      g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                                   _("Invalid sequence in conversion input"));
+	      goto err_out;
+	    }
+	}
+      else
+	{
+	  if (high_surrogate)
+	    {
+	      g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                                   _("Invalid sequence in conversion input"));
+	      goto err_out;
+	    }
+
+	  if (c >= 0xd800 && c < 0xdc00) /* high surrogate */
+	    {
+	      high_surrogate = c;
+	      goto next1;
+	    }
+	  else
+	    wc = c;
+	}
+
+      /********** DIFFERENT for UTF8/UCS4 **********/
+      n_bytes += UTF8_LENGTH (wc);
+
+    next1:
+      in++;
+    }
+
+  if (high_surrogate && !items_read)
+    {
+      g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_PARTIAL_INPUT,
+                           _("Partial character sequence at end of input"));
+      goto err_out;
+    }
+  
+  /* At this point, everything is valid, and we just need to convert
+   */
+  /********** DIFFERENT for UTF8/UCS4 **********/
+  result = g_malloc (n_bytes + 1);
+  
+  high_surrogate = 0;
+  out = result;
+  in = str;
+  while (out < result + n_bytes)
+    {
+      gunichar2 c = *in;
+      gunichar wc;
+
+      if (c >= 0xdc00 && c < 0xe000) /* low surrogate */
+	{
+	  wc = SURROGATE_VALUE (high_surrogate, c);
+	  high_surrogate = 0;
+	}
+      else if (c >= 0xd800 && c < 0xdc00) /* high surrogate */
+	{
+	  high_surrogate = c;
+	  goto next2;
+	}
+      else
+	wc = c;
+
+      /********** DIFFERENT for UTF8/UCS4 **********/
+      out += g_unichar_to_utf8 (wc, out);
+
+    next2:
+      in++;
+    }
+  
+  /********** DIFFERENT for UTF8/UCS4 **********/
+  *out = '\0';
+
+  if (items_written)
+    /********** DIFFERENT for UTF8/UCS4 **********/
+    *items_written = out - result;
+
+ err_out:
+  if (items_read)
+    *items_read = in - str;
+
+  return result;
+}
+
+/**
+ * g_utf16_to_ucs4:
+ * @str: a UTF-16 encoded string
+ * @len: the maximum length (number of <type>gunichar2</type>) of @str to use. 
+ *       If @len < 0, then the string is nul-terminated.
+ * @items_read: location to store number of words read, or %NULL.
+ *              If %NULL, then %G_CONVERT_ERROR_PARTIAL_INPUT will be
+ *              returned in case @str contains a trailing partial
+ *              character. If an error occurs then the index of the
+ *              invalid input is stored here.
+ * @items_written: location to store number of characters written, or %NULL.
+ *                 The value stored here does not include the trailing
+ *                 0 character.
+ * @error: location to store the error occuring, or %NULL to ignore
+ *         errors. Any of the errors in #GConvertError other than
+ *         %G_CONVERT_ERROR_NO_CONVERSION may occur.
+ *
+ * Convert a string from UTF-16 to UCS-4. The result will be
+ * nul-terminated.
+ * 
+ * Return value: a pointer to a newly allocated UCS-4 string.
+ *               This value must be freed with g_free(). If an
+ *               error occurs, %NULL will be returned and
+ *               @error set.
+ **/
+gunichar *
+g_utf16_to_ucs4 (const gunichar2  *str,
+		 glong             len,              
+		 glong            *items_read,       
+		 glong            *items_written,    
+		 GError          **error)
+{
+  const gunichar2 *in;
+  gchar *out;
+  gchar *result = NULL;
+  gint n_bytes;
+  gunichar high_surrogate;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  n_bytes = 0;
+  in = str;
+  high_surrogate = 0;
+  while ((len < 0 || in - str < len) && *in)
+    {
+      gunichar2 c = *in;
+      gunichar wc;
+
+      if (c >= 0xdc00 && c < 0xe000) /* low surrogate */
+	{
+	  if (high_surrogate)
+	    {
+	      wc = SURROGATE_VALUE (high_surrogate, c);
+	      high_surrogate = 0;
+	    }
+	  else
+	    {
+	      g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                                   _("Invalid sequence in conversion input"));
+	      goto err_out;
+	    }
+	}
+      else
+	{
+	  if (high_surrogate)
+	    {
+	      g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                                   _("Invalid sequence in conversion input"));
+	      goto err_out;
+	    }
+
+	  if (c >= 0xd800 && c < 0xdc00) /* high surrogate */
+	    {
+	      high_surrogate = c;
+	      goto next1;
+	    }
+	  else
+	    wc = c;
+	}
+
+      /********** DIFFERENT for UTF8/UCS4 **********/
+      n_bytes += sizeof (gunichar);
+
+    next1:
+      in++;
+    }
+
+  if (high_surrogate && !items_read)
+    {
+      g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_PARTIAL_INPUT,
+                           _("Partial character sequence at end of input"));
+      goto err_out;
+    }
+  
+  /* At this point, everything is valid, and we just need to convert
+   */
+  /********** DIFFERENT for UTF8/UCS4 **********/
+  result = g_malloc (n_bytes + 4);
+  
+  high_surrogate = 0;
+  out = result;
+  in = str;
+  while (out < result + n_bytes)
+    {
+      gunichar2 c = *in;
+      gunichar wc;
+
+      if (c >= 0xdc00 && c < 0xe000) /* low surrogate */
+	{
+	  wc = SURROGATE_VALUE (high_surrogate, c);
+	  high_surrogate = 0;
+	}
+      else if (c >= 0xd800 && c < 0xdc00) /* high surrogate */
+	{
+	  high_surrogate = c;
+	  goto next2;
+	}
+      else
+	wc = c;
+
+      /********** DIFFERENT for UTF8/UCS4 **********/
+      *(gunichar *)out = wc;
+      out += sizeof (gunichar);
+
+    next2:
+      in++;
+    }
+
+  /********** DIFFERENT for UTF8/UCS4 **********/
+  *(gunichar *)out = 0;
+
+  if (items_written)
+    /********** DIFFERENT for UTF8/UCS4 **********/
+    *items_written = (out - result) / sizeof (gunichar);
+
+ err_out:
+  if (items_read)
+    *items_read = in - str;
+
+  return (gunichar *)result;
+}
+
+/**
+ * g_utf8_to_utf16:
+ * @str: a UTF-8 encoded string
+ * @len: the maximum length (number of bytes) of @str to use.
+ *       If @len < 0, then the string is nul-terminated.
+ * @items_read: location to store number of bytes read, or %NULL.
+ *              If %NULL, then %G_CONVERT_ERROR_PARTIAL_INPUT will be
+ *              returned in case @str contains a trailing partial
+ *              character. If an error occurs then the index of the
+ *              invalid input is stored here.
+ * @items_written: location to store number of <type>gunichar2</type> written,
+ *                 or %NULL.
+ *                 The value stored here does not include the trailing 0.
+ * @error: location to store the error occuring, or %NULL to ignore
+ *         errors. Any of the errors in #GConvertError other than
+ *         %G_CONVERT_ERROR_NO_CONVERSION may occur.
+ *
+ * Convert a string from UTF-8 to UTF-16. A 0 character will be
+ * added to the result after the converted text.
+ *
+ * Return value: a pointer to a newly allocated UTF-16 string.
+ *               This value must be freed with g_free(). If an
+ *               error occurs, %NULL will be returned and
+ *               @error set.
+ **/
+gunichar2 *
+g_utf8_to_utf16 (const gchar *str,
+		 glong        len,
+		 glong       *items_read,
+		 glong       *items_written,
+		 GError     **error)
+{
+  gunichar2 *result = NULL;
+  gint n16;
+  const gchar *in;
+  gint i;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  in = str;
+  n16 = 0;
+  while ((len < 0 || str + len - in > 0) && *in)
+    {
+      gunichar wc = g_utf8_get_char_extended (in, len < 0 ? 6 : str + len - in);
+      if (wc & 0x80000000)
+	{
+	  if (wc == (gunichar)-2)
+	    {
+	      if (items_read)
+		break;
+	      else
+		g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_PARTIAL_INPUT,
+                                     _("Partial character sequence at end of input"));
+	    }
+	  else
+	    g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                                 _("Invalid byte sequence in conversion input"));
+
+	  goto err_out;
+	}
+
+      if (wc < 0xd800)
+	n16 += 1;
+      else if (wc < 0xe000)
+	{
+	  g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                               _("Invalid sequence in conversion input"));
+
+	  goto err_out;
+	}
+      else if (wc < 0x10000)
+	n16 += 1;
+      else if (wc < 0x110000)
+	n16 += 2;
+      else
+	{
+	  g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                               _("Character out of range for UTF-16"));
+
+	  goto err_out;
+	}
+      
+      in = g_utf8_next_char (in);
+    }
+
+  result = g_new (gunichar2, n16 + 1);
+  
+  in = str;
+  for (i = 0; i < n16;)
+    {
+      gunichar wc = g_utf8_get_char (in);
+
+      if (wc < 0x10000)
+	{
+	  result[i++] = wc;
+	}
+      else
+	{
+	  result[i++] = (wc - 0x10000) / 0x400 + 0xd800;
+	  result[i++] = (wc - 0x10000) % 0x400 + 0xdc00;
+	}
+      
+      in = g_utf8_next_char (in);
+    }
+
+  result[i] = 0;
+
+  if (items_written)
+    *items_written = n16;
+
+ err_out:
+  if (items_read)
+    *items_read = in - str;
+  
+  return result;
+}
+
+/**
+ * g_ucs4_to_utf16:
+ * @str: a UCS-4 encoded string
+ * @len: the maximum length (number of characters) of @str to use. 
+ *       If @len < 0, then the string is nul-terminated.
+ * @items_read: location to store number of bytes read, or %NULL.
+ *              If an error occurs then the index of the invalid input
+ *              is stored here.
+ * @items_written: location to store number of <type>gunichar2</type> 
+ *                 written, or %NULL. The value stored here does not 
+ *                 include the trailing 0.
+ * @error: location to store the error occuring, or %NULL to ignore
+ *         errors. Any of the errors in #GConvertError other than
+ *         %G_CONVERT_ERROR_NO_CONVERSION may occur.
+ *
+ * Convert a string from UCS-4 to UTF-16. A 0 character will be
+ * added to the result after the converted text.
+ * 
+ * Return value: a pointer to a newly allocated UTF-16 string.
+ *               This value must be freed with g_free(). If an
+ *               error occurs, %NULL will be returned and
+ *               @error set.
+ **/
+gunichar2 *
+g_ucs4_to_utf16 (const gunichar  *str,
+		 glong            len,              
+		 glong           *items_read,       
+		 glong           *items_written,    
+		 GError         **error)
+{
+  gunichar2 *result = NULL;
+  gint n16;
+  gint i, j;
+
+  n16 = 0;
+  i = 0;
+  while ((len < 0 || i < len) && str[i])
+    {
+      gunichar wc = str[i];
+
+      if (wc < 0xd800)
+	n16 += 1;
+      else if (wc < 0xe000)
+	{
+	  g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                               _("Invalid sequence in conversion input"));
+
+	  goto err_out;
+	}
+      else if (wc < 0x10000)
+	n16 += 1;
+      else if (wc < 0x110000)
+	n16 += 2;
+      else
+	{
+	  g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
+                               _("Character out of range for UTF-16"));
+
+	  goto err_out;
+	}
+
+      i++;
+    }
+  
+  result = g_new (gunichar2, n16 + 1);
+  
+  for (i = 0, j = 0; j < n16; i++)
+    {
+      gunichar wc = str[i];
+
+      if (wc < 0x10000)
+	{
+	  result[j++] = wc;
+	}
+      else
+	{
+	  result[j++] = (wc - 0x10000) / 0x400 + 0xd800;
+	  result[j++] = (wc - 0x10000) % 0x400 + 0xdc00;
+	}
+    }
+  result[j] = 0;
+
+  if (items_written)
+    *items_written = n16;
+  
+ err_out:
+  if (items_read)
+    *items_read = i;
+  
+  return result;
+}
+
+#define CONTINUATION_CHAR                           \
+ G_STMT_START {                                     \
+  if ((*(guchar *)p & 0xc0) != 0x80) /* 10xxxxxx */ \
+    goto error;                                     \
+  val <<= 6;                                        \
+  val |= (*(guchar *)p) & 0x3f;                     \
+ } G_STMT_END
+
+static const gchar *
+fast_validate (const char *str)
+
+{
+  gunichar val = 0;
+  gunichar min = 0;
+  const gchar *p;
+
+  for (p = str; *p; p++)
+    {
+      if (*(guchar *)p < 128)
+	/* done */;
+      else 
+	{
+	  const gchar *last;
+	  
+	  last = p;
+	  if ((*(guchar *)p & 0xe0) == 0xc0) /* 110xxxxx */
+	    {
+	      if (G_UNLIKELY ((*(guchar *)p & 0x1e) == 0))
+		goto error;
+	      p++;
+	      if (G_UNLIKELY ((*(guchar *)p & 0xc0) != 0x80)) /* 10xxxxxx */
+		goto error;
+	    }
+	  else
+	    {
+	      if ((*(guchar *)p & 0xf0) == 0xe0) /* 1110xxxx */
+		{
+		  min = (1 << 11);
+		  val = *(guchar *)p & 0x0f;
+		  goto TWO_REMAINING;
+		}
+	      else if ((*(guchar *)p & 0xf8) == 0xf0) /* 11110xxx */
+		{
+		  min = (1 << 16);
+		  val = *(guchar *)p & 0x07;
+		}
+	      else
+		goto error;
+	      
+	      p++;
+	      CONTINUATION_CHAR;
+	    TWO_REMAINING:
+	      p++;
+	      CONTINUATION_CHAR;
+	      p++;
+	      CONTINUATION_CHAR;
+	      
+	      if (G_UNLIKELY (val < min))
+		goto error;
+
+	      if (G_UNLIKELY (!UNICODE_VALID(val)))
+		goto error;
+	    } 
+	  
+	  continue;
+	  
+	error:
+	  return last;
+	}
+    }
+
+  return p;
+}
+
+static const gchar *
+fast_validate_len (const char *str,
+		   gssize      max_len)
+
+{
+  gunichar val = 0;
+  gunichar min = 0;
+  const gchar *p;
+
+  g_assert (max_len >= 0);
+
+  for (p = str; ((p - str) < max_len) && *p; p++)
+    {
+      if (*(guchar *)p < 128)
+	/* done */;
+      else 
+	{
+	  const gchar *last;
+	  
+	  last = p;
+	  if ((*(guchar *)p & 0xe0) == 0xc0) /* 110xxxxx */
+	    {
+	      if (G_UNLIKELY (max_len - (p - str) < 2))
+		goto error;
+	      
+	      if (G_UNLIKELY ((*(guchar *)p & 0x1e) == 0))
+		goto error;
+	      p++;
+	      if (G_UNLIKELY ((*(guchar *)p & 0xc0) != 0x80)) /* 10xxxxxx */
+		goto error;
+	    }
+	  else
+	    {
+	      if ((*(guchar *)p & 0xf0) == 0xe0) /* 1110xxxx */
+		{
+		  if (G_UNLIKELY (max_len - (p - str) < 3))
+		    goto error;
+		  
+		  min = (1 << 11);
+		  val = *(guchar *)p & 0x0f;
+		  goto TWO_REMAINING;
+		}
+ 	      else if ((*(guchar *)p & 0xf8) == 0xf0) /* 11110xxx */
+		{
+		  if (G_UNLIKELY (max_len - (p - str) < 4))
+		    goto error;
+		  
+		  min = (1 << 16);
+		  val = *(guchar *)p & 0x07;
+		}
+	      else
+		goto error;
+	      
+	      p++;
+	      CONTINUATION_CHAR;
+	    TWO_REMAINING:
+	      p++;
+	      CONTINUATION_CHAR;
+	      p++;
+	      CONTINUATION_CHAR;
+	      
+	      if (G_UNLIKELY (val < min))
+		goto error;
+	      if (G_UNLIKELY (!UNICODE_VALID(val)))
+		goto error;
+	    } 
+	  
+	  continue;
+	  
+	error:
+	  return last;
+	}
+    }
+
+  return p;
+}
+
+/**
+ * g_utf8_validate:
+ * @str: a pointer to character data
+ * @max_len: max bytes to validate, or -1 to go until NUL
+ * @end: return location for end of valid data
+ * 
+ * Validates UTF-8 encoded text. @str is the text to validate;
+ * if @str is nul-terminated, then @max_len can be -1, otherwise
+ * @max_len should be the number of bytes to validate.
+ * If @end is non-%NULL, then the end of the valid range
+ * will be stored there (i.e. the start of the first invalid 
+ * character if some bytes were invalid, or the end of the text 
+ * being validated otherwise).
+ *
+ * Note that g_utf8_validate() returns %FALSE if @max_len is 
+ * positive and NUL is met before @max_len bytes have been read.
+ *
+ * Returns %TRUE if all of @str was valid. Many GLib and GTK+
+ * routines <emphasis>require</emphasis> valid UTF-8 as input;
+ * so data read from a file or the network should be checked
+ * with g_utf8_validate() before doing anything else with it.
+ * 
+ * Return value: %TRUE if the text was valid UTF-8
+ **/
+gboolean
+g_utf8_validate (const char   *str,
+		 gssize        max_len,    
+		 const gchar **end)
+
+{
+  const gchar *p;
+
+  if (max_len < 0)
+    p = fast_validate (str);
+  else
+    p = fast_validate_len (str, max_len);
+
+  if (end)
+    *end = p;
+
+  if ((max_len >= 0 && p != str + max_len) ||
+      (max_len < 0 && *p != '\0'))
+    return FALSE;
+  else
+    return TRUE;
+}
+
+/**
+ * g_unichar_validate:
+ * @ch: a Unicode character
+ * 
+ * Checks whether @ch is a valid Unicode character. Some possible
+ * integer values of @ch will not be valid. 0 is considered a valid
+ * character, though it's normally a string terminator.
+ * 
+ * Return value: %TRUE if @ch is a valid Unicode character
+ **/
+gboolean
+g_unichar_validate (gunichar ch)
+{
+  return UNICODE_VALID (ch);
+}
+
+/**
+ * g_utf8_strreverse:
+ * @str: a UTF-8 encoded string
+ * @len: the maximum length of @str to use, in bytes. If @len < 0,
+ *       then the string is nul-terminated.
+ *
+ * Reverses a UTF-8 string. @str must be valid UTF-8 encoded text. 
+ * (Use g_utf8_validate() on all text before trying to use UTF-8 
+ * utility functions with it.)
+ *
+ * This function is intended for programmatic uses of reversed strings.
+ * It pays no attention to decomposed characters, combining marks, byte 
+ * order marks, directional indicators (LRM, LRO, etc) and similar 
+ * characters which might need special handling when reversing a string 
+ * for display purposes.
+ *
+ * Note that unlike g_strreverse(), this function returns
+ * newly-allocated memory, which should be freed with g_free() when
+ * no longer needed. 
+ *
+ * Returns: a newly-allocated string which is the reverse of @str.
+ *
+ * Since: 2.2
+ */
+gchar *
+g_utf8_strreverse (const gchar *str,
+		   gssize       len)
+{
+  gchar *r, *result;
+  const gchar *p;
+
+  if (len < 0)
+    len = strlen (str);
+
+  result = g_new (gchar, len + 1);
+  r = result + len;
+  p = str;
+  while (r > result)
+    {
+      gchar *m, skip = g_utf8_skip[*(guchar*) p];
+      r -= skip;
+      for (m = r; skip; skip--)
+        *m++ = *p++;
+    }
+  result[len] = 0;
+
+  return result;
+}
+
+
+gchar *
+_g_utf8_make_valid (const gchar *name)
+{
+  GString *string;
+  const gchar *remainder, *invalid;
+  gint remaining_bytes, valid_bytes;
+
+  g_return_val_if_fail (name != NULL, NULL);
+
+  string = NULL;
+  remainder = name;
+  remaining_bytes = strlen (name);
+
+  while (remaining_bytes != 0) 
+    {
+      if (g_utf8_validate (remainder, remaining_bytes, &invalid)) 
+	break;
+      valid_bytes = invalid - remainder;
+    
+      if (string == NULL) 
+	string = g_string_sized_new (remaining_bytes);
+
+      g_string_append_len (string, remainder, valid_bytes);
+      /* append U+FFFD REPLACEMENT CHARACTER */
+      g_string_append (string, "\357\277\275");
+      
+      remaining_bytes -= valid_bytes + 1;
+      remainder = invalid + 1;
+    }
+  
+  if (string == NULL)
+    return g_strdup (name);
+  
+  g_string_append (string, remainder);
+
+  g_assert (g_utf8_validate (string->str, -1, NULL));
+  
+  return g_string_free (string, FALSE);
+}