gnu/dist/gettext/gettext-tools/lib/ucs4-utf8.h

   1 /* Conversion UCS-4 to UTF-8.
   2    Copyright (C) 2002 Free Software Foundation, Inc.
   3    Written by Bruno Haible <haible@clisp.cons.org>, 2002.
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19
  20 #include <stddef.h>
  21
  22 /* Return the length (number of units) of the UTF-8 representation of uc,
  23    after storing it at S.  Return -1 upon failure, -2 if the number of
  24    available units, N, is too small.  */
  25 static int
  26 u8_uctomb_aux (unsigned char *s, unsigned int uc, int n)
  27 {
  28   int count;
  29
  30   if (uc < 0x80)
  31     count = 1;
  32   else if (uc < 0x800)
  33     count = 2;
  34   else if (uc < 0x10000)
  35     count = 3;
  36 #if 0
  37   else if (uc < 0x200000)
  38     count = 4;
  39   else if (uc < 0x4000000)
  40     count = 5;
  41   else if (uc <= 0x7fffffff)
  42     count = 6;
  43 #else
  44   else if (uc < 0x110000)
  45     count = 4;
  46 #endif
  47   else
  48     return -1;
  49
  50   if (n < count)
  51     return -2;
  52
  53   switch (count) /* note: code falls through cases! */
  54     {
  55 #if 0
  56     case 6: s[5] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x4000000;
  57     case 5: s[4] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x200000;
  58 #endif
  59     case 4: s[3] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x10000;
  60     case 3: s[2] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x800;
  61     case 2: s[1] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0xc0;
  62     case 1: s[0] = uc;
  63     }
  64   return count;
  65 }
  66
  67 static inline int
  68 u8_uctomb (unsigned char *s, unsigned int uc, int n)
  69 {
  70   if (uc < 0x80 && n > 0)
  71     {
  72       s[0] = uc;
  73       return 1;
  74     }
  75   else
  76     return u8_uctomb_aux (s, uc, n);
  77 }