iconv/iconv.c

   1 /* Convert characters in input buffer using conversion descriptor to
   2    output buffer.
   3    Copyright (C) 1997-2023 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   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    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <stddef.h> /* for NULL */
  21 #include <errno.h>
  22 #include <iconv.h>
  23
  24 #include <gconv_int.h>
  25
  26 #include <assert.h>
  27
  28
  29 size_t
  30 iconv (iconv_t cd, char **inbuf, size_t *inbytesleft, char **outbuf,
  31        size_t *outbytesleft)
  32 {
  33   __gconv_t gcd = (__gconv_t) cd;
  34   char *outstart = outbuf ? *outbuf : NULL;
  35   size_t irreversible;
  36   int result;
  37
  38   if (__glibc_unlikely (inbuf == NULL || *inbuf == NULL))
  39     {
  40       if (outbuf == NULL || *outbuf == NULL)
  41         result = __gconv (gcd, NULL, NULL, NULL, NULL, &irreversible);
  42       else
  43         result = __gconv (gcd, NULL, NULL, (unsigned char **) outbuf,
  44                           (unsigned char *) (outstart + *outbytesleft),
  45                           &irreversible);
  46     }
  47   else
  48     {
  49       const char *instart = *inbuf;
  50
  51       result = __gconv (gcd, (const unsigned char **) inbuf,
  52                         (const unsigned char *)  (*inbuf + *inbytesleft),
  53                         (unsigned char **) outbuf,
  54                         (unsigned char *) (*outbuf + *outbytesleft),
  55                         &irreversible);
  56
  57       *inbytesleft -= *inbuf - instart;
  58     }
  59   if (outstart != NULL)
  60     *outbytesleft -= *outbuf - outstart;
  61
  62   switch (__builtin_expect (result, __GCONV_OK))
  63     {
  64     case __GCONV_ILLEGAL_DESCRIPTOR:
  65       __set_errno (EBADF);
  66       irreversible = (size_t) -1L;
  67       break;
  68
  69     case __GCONV_ILLEGAL_INPUT:
  70       __set_errno (EILSEQ);
  71       irreversible = (size_t) -1L;
  72       break;
  73
  74     case __GCONV_FULL_OUTPUT:
  75       __set_errno (E2BIG);
  76       irreversible = (size_t) -1L;
  77       break;
  78
  79     case __GCONV_INCOMPLETE_INPUT:
  80       __set_errno (EINVAL);
  81       irreversible = (size_t) -1L;
  82       break;
  83
  84     case __GCONV_EMPTY_INPUT:
  85     case __GCONV_OK:
  86       /* Nothing.  */
  87       break;
  88
  89     default:
  90       assert (!"Nothing like this should happen");
  91     }
  92
  93   return irreversible;
  94 }