libguile/extchrs.c

   1 /*      Copyright (C) 1995,1996 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  16  *
  17  * As a special exception, the Free Software Foundation gives permission
  18  * for additional uses of the text contained in its release of GUILE.
  19  *
  20  * The exception is that, if you link the GUILE library with other files
  21  * to produce an executable, this does not by itself cause the
  22  * resulting executable to be covered by the GNU General Public License.
  23  * Your use of that executable is in no way restricted on account of
  24  * linking the GUILE library code into it.
  25  *
  26  * This exception does not however invalidate any other reasons why
  27  * the executable file might be covered by the GNU General Public License.
  28  *
  29  * This exception applies only to the code released by the
  30  * Free Software Foundation under the name GUILE.  If you copy
  31  * code from other Free Software Foundation releases into a copy of
  32  * GUILE, as the General Public License permits, the exception does
  33  * not apply to the code that you add in this way.  To avoid misleading
  34  * anyone as to the status of such modified files, you must delete
  35  * this exception notice from them.
  36  *
  37  * If you write modifications of your own for GUILE, it is your choice
  38  * whether to permit this exception to apply to your modifications.
  39  * If you do not wish that, delete this exception notice.
  40  */
  41 \f
  42
  43 #include "extchrs.h"
  44
  45 \f
  46
  47 #ifdef FAKE_EXT_SCM_CHARS
  48
  49 #ifdef __STDC__
  50 int
  51 xmblen (const char * str, size_t size)
  52 #else
  53 int
  54 xmblen (str, size)
  55      const char * str;
  56      size_t size;
  57 #endif
  58 {
  59   if (!str)
  60     return 0;
  61
  62   if (*(unsigned char *)str > 127)
  63     return ((size < 4)
  64             ? -1
  65             : 4);
  66   else if (!*str)
  67     return 0;
  68   else
  69     return 1;
  70 }
  71
  72 #ifdef __STDC__
  73 int
  74 xwctomb (char * _str, int c)
  75 #else
  76 int
  77 xwctomb (_str, c)
  78      char * _str;
  79      int c;
  80 #endif
  81 {
  82   unsigned char * str;
  83   str = (unsigned char *)_str;
  84   if (!str)
  85     return 0;
  86
  87   if (!c)
  88     {
  89       *str = 0;
  90       return 0;
  91     }
  92
  93
  94   if (c < 127)
  95     {
  96       *str = c;
  97       return 1;
  98     }
  99
 100   str[0] = 255;
 101   str[1] = 0x80 | ((c >> 10) & 0x3f);
 102   str[2] = 0x80 | ((c >> 4) & 0x3f);
 103   str[3] = 0x80 | (c & 0xf);
 104   return 4;
 105 }
 106
 107 #ifdef __STDC__
 108 int
 109 xmbtowc (xwchar_t * result, const unsigned char * _str, size_t size)
 110 #else
 111 int
 112 xmbtowc (result, str, size)
 113      xwchar_t * result;
 114      const unsigned char * _str;
 115      size_t size;
 116 #endif
 117 {
 118   const unsigned char * str;
 119   str = (const unsigned char *)_str;
 120   if (!str)
 121     return 0;
 122
 123   if ((size == 0) || !*str)
 124     {
 125       *result = 0;
 126       return 0;
 127     }
 128
 129   if (*str < 128)
 130     {
 131       *result = *str;
 132       return 1;
 133     }
 134
 135   if (   (*str != 255)
 136       || (size < 4))
 137     return -1;
 138
 139   *result = (  ((str[1] & 0x3f) << 10)
 140              | ((str[2] & 0x3f) << 4)
 141              | (str[3] & 0xf));
 142   return 4;
 143 }
 144
 145 #endif /* FAKE_EXT_SCM_CHARS */
 146