iconv/iconv_open.c

   1 /* Get descriptor for character set conversion.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <ctype.h>
  22 #include <errno.h>
  23 #include <iconv.h>
  24 #include <string.h>
  25
  26 #include <gconv.h>
  27
  28
  29 static inline void
  30 strip (char *wp, const char *s)
  31 {
  32   int slash_count = 0;
  33
  34   while (*s != '\0')
  35     {
  36       if (isalnum (*s) || *s == '_' || *s == '-' || *s == '.')
  37         *wp++ = *s;
  38       else if (*s == '/')
  39         {
  40           if (++slash_count == 3)
  41             break;
  42           *wp++ = '/';
  43         }
  44       ++s;
  45     }
  46
  47   while (slash_count++ < 2)
  48     *wp++ = '/';
  49
  50   *wp = '\0';
  51 }
  52
  53
  54 iconv_t
  55 iconv_open (const char *tocode, const char *fromcode)
  56 {
  57   char *tocode_conv;
  58   char *fromcode_conv;
  59   size_t tocode_len;
  60   size_t fromcode_len;
  61   gconv_t cd;
  62   int res;
  63
  64   /* Normalize the name.  We remove all characters beside alpha-numeric,
  65      '_', '-', '/', and '.'.  */
  66   tocode_len = strlen (tocode);
  67   tocode_conv = alloca (tocode_len + 3);
  68   strip (tocode_conv, tocode);
  69
  70   fromcode_len = strlen (fromcode);
  71   fromcode_conv = alloca (fromcode_len + 3);
  72   strip (fromcode_conv, fromcode);
  73
  74   res = __gconv_open (tocode_conv[2] == '\0' ? tocode : tocode_conv,
  75                       fromcode_conv[2] == '\0' ? fromcode : fromcode_conv,
  76                       &cd);
  77
  78   if (res != GCONV_OK)
  79     {
  80       /* We must set the error number according to the specs.  */
  81       if (res == GCONV_NOCONV || res == GCONV_NODB)
  82         __set_errno (EINVAL);
  83
  84       return (iconv_t) -1;
  85     }
  86
  87   return (iconv_t) cd;
  88 }