iconv/iconv_open.c

   1 /* Get descriptor for character set conversion.
   2    Copyright (C) 1997, 1998, 1999 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 <stdlib.h>
  25 #include <string.h>
  26
  27 #include <gconv_int.h>
  28
  29
  30 static inline void
  31 strip (char *wp, const char *s)
  32 {
  33   int slash_count = 0;
  34
  35   while (*s != '\0')
  36     {
  37       if (isalnum (*s) || *s == '_' || *s == '-' || *s == '.')
  38         *wp++ = toupper (*s);
  39       else if (*s == '/')
  40         {
  41           if (++slash_count == 3)
  42             break;
  43           *wp++ = '/';
  44         }
  45       ++s;
  46     }
  47
  48   while (slash_count++ < 2)
  49     *wp++ = '/';
  50
  51   *wp = '\0';
  52 }
  53
  54
  55 static char *
  56 upstr (char *dst, const char *str)
  57 {
  58   char *cp = dst;
  59   while ((*cp++ = toupper (*str++)) != '\0')
  60     /* nothing */;
  61   return dst;
  62 }
  63
  64
  65 iconv_t
  66 iconv_open (const char *tocode, const char *fromcode)
  67 {
  68   char *tocode_conv;
  69   char *fromcode_conv;
  70   size_t tocode_len;
  71   size_t fromcode_len;
  72   gconv_t cd;
  73   int res;
  74
  75   /* Normalize the name.  We remove all characters beside alpha-numeric,
  76      '_', '-', '/', and '.'.  */
  77   tocode_len = strlen (tocode);
  78   tocode_conv = alloca (tocode_len + 3);
  79   strip (tocode_conv, tocode);
  80   tocode = tocode_conv[2] == '\0' ? upstr (tocode_conv, tocode) : tocode_conv;
  81
  82   fromcode_len = strlen (fromcode);
  83   fromcode_conv = alloca (fromcode_len + 3);
  84   strip (fromcode_conv, fromcode);
  85   fromcode = (fromcode_conv[2] == '\0'
  86               ? upstr (fromcode_conv, fromcode) : fromcode_conv);
  87
  88   res = __gconv_open (tocode, fromcode, &cd);
  89
  90   if (res != GCONV_OK)
  91     {
  92       /* We must set the error number according to the specs.  */
  93       if (res == GCONV_NOCONV || res == GCONV_NODB)
  94         __set_errno (EINVAL);
  95
  96       return (iconv_t) -1;
  97     }
  98
  99   return (iconv_t) cd;
 100 }