iconv/iconv.c

   1 /* Convert characters in input buffer using conversion descriptor to
   2    output buffer.
   3    Copyright (C) 1997-2020 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <https://www.gnu.org/licenses/>.  */
  20
  21 #include <stddef.h> /* for NULL */
  22 #include <errno.h>
  23 #include <iconv.h>
  24
  25 #include <gconv_int.h>
  26
  27 #include <assert.h>
  28
  29
  30 size_t
  31 iconv (iconv_t cd, char **inbuf, size_t *inbytesleft, char **outbuf,
  32        size_t *outbytesleft)
  33 {
  34   __gconv_t gcd = (__gconv_t) cd;
  35   char *outstart = outbuf ? *outbuf : NULL;
  36   size_t irreversible;
  37   int result;
  38
  39   if (__glibc_unlikely (inbuf == NULL || *inbuf == NULL))
  40     {
  41       if (outbuf == NULL || *outbuf == NULL)
  42         result = __gconv (gcd, NULL, NULL, NULL, NULL, &irreversible);
  43       else
  44         result = __gconv (gcd, NULL, NULL, (unsigned char **) outbuf,
  45                           (unsigned char *) (outstart + *outbytesleft),
  46                           &irreversible);
  47     }
  48   else
  49     {
  50       const char *instart = *inbuf;
  51
  52       result = __gconv (gcd, (const unsigned char **) inbuf,
  53                         (const unsigned char *)  (*inbuf + *inbytesleft),
  54                         (unsigned char **) outbuf,
  55                         (unsigned char *) (*outbuf + *outbytesleft),
  56                         &irreversible);
  57
  58       *inbytesleft -= *inbuf - instart;
  59     }
  60   if (outstart != NULL)
  61     *outbytesleft -= *outbuf - outstart;
  62
  63   switch (__builtin_expect (result, __GCONV_OK))
  64     {
  65     case __GCONV_ILLEGAL_DESCRIPTOR:
  66       __set_errno (EBADF);
  67       irreversible = (size_t) -1L;
  68       break;
  69
  70     case __GCONV_ILLEGAL_INPUT:
  71       __set_errno (EILSEQ);
  72       irreversible = (size_t) -1L;
  73       break;
  74
  75     case __GCONV_FULL_OUTPUT:
  76       __set_errno (E2BIG);
  77       irreversible = (size_t) -1L;
  78       break;
  79
  80     case __GCONV_INCOMPLETE_INPUT:
  81       __set_errno (EINVAL);
  82       irreversible = (size_t) -1L;
  83       break;
  84
  85     case __GCONV_EMPTY_INPUT:
  86     case __GCONV_OK:
  87       /* Nothing.  */
  88       break;
  89
  90     default:
  91       assert (!"Nothing like this should happen");
  92     }
  93
  94   return irreversible;
  95 }