iconv/iconv_open.c

   1 /* Get descriptor for character set conversion.
   2    Copyright (C) 1997-2015 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 Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <alloca.h>
  21 #include <errno.h>
  22 #include <iconv.h>
  23 #include <stdbool.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include <gconv_int.h>
  28 #include "gconv_charset.h"
  29
  30
  31 iconv_t
  32 iconv_open (const char *tocode, const char *fromcode)
  33 {
  34   /* Normalize the name.  We remove all characters beside alpha-numeric,
  35      '_', '-', '/', '.', and ':'.  */
  36   size_t tocode_len = strlen (tocode) + 3;
  37   char *tocode_conv;
  38   bool tocode_usealloca = __libc_use_alloca (tocode_len);
  39   if (tocode_usealloca)
  40     tocode_conv = (char *) alloca (tocode_len);
  41   else
  42     {
  43       tocode_conv = (char *) malloc (tocode_len);
  44       if (tocode_conv == NULL)
  45         return (iconv_t) -1;
  46     }
  47   strip (tocode_conv, tocode);
  48   tocode = (tocode_conv[2] == '\0' && tocode[0] != '\0'
  49             ? upstr (tocode_conv, tocode) : tocode_conv);
  50
  51   size_t fromcode_len = strlen (fromcode) + 3;
  52   char *fromcode_conv;
  53   bool fromcode_usealloca = __libc_use_alloca (fromcode_len);
  54   if (fromcode_usealloca)
  55     fromcode_conv = (char *) alloca (fromcode_len);
  56   else
  57     {
  58       fromcode_conv = (char *) malloc (fromcode_len);
  59       if (fromcode_conv == NULL)
  60         {
  61           if (! tocode_usealloca)
  62             free (tocode_conv);
  63           return (iconv_t) -1;
  64         }
  65     }
  66   strip (fromcode_conv, fromcode);
  67   fromcode = (fromcode_conv[2] == '\0' && fromcode[0] != '\0'
  68               ? upstr (fromcode_conv, fromcode) : fromcode_conv);
  69
  70   __gconv_t cd;
  71   int res = __gconv_open (tocode, fromcode, &cd, 0);
  72
  73   if (! fromcode_usealloca)
  74     free (fromcode_conv);
  75   if (! tocode_usealloca)
  76     free (tocode_conv);
  77
  78   if (__builtin_expect (res, __GCONV_OK) != __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       cd = (iconv_t) -1;
  85     }
  86
  87   return (iconv_t) cd;
  88 }