iconv/gconv.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 <assert.h>
  21 #include <dlfcn.h>
  22 #include <stddef.h>
  23 #include <sys/param.h>
  24
  25 #include <gconv_int.h>
  26 #include <pointer_guard.h>
  27
  28
  29 int
  30 __gconv (__gconv_t cd, const unsigned char **inbuf,
  31          const unsigned char *inbufend, unsigned char **outbuf,
  32          unsigned char *outbufend, size_t *irreversible)
  33 {
  34   size_t last_step;
  35   int result;
  36
  37   if (cd == (__gconv_t) -1L)
  38     return __GCONV_ILLEGAL_DESCRIPTOR;
  39
  40   last_step = cd->__nsteps - 1;
  41
  42   assert (irreversible != NULL);
  43   *irreversible = 0;
  44
  45   cd->__data[last_step].__outbuf = outbuf != NULL ? *outbuf : NULL;
  46   cd->__data[last_step].__outbufend = outbufend;
  47
  48   __gconv_fct fct = cd->__steps->__fct;
  49   if (cd->__steps->__shlib_handle != NULL)
  50     PTR_DEMANGLE (fct);
  51
  52   if (inbuf == NULL || *inbuf == NULL)
  53     {
  54       /* We just flush.  */
  55       result = DL_CALL_FCT (fct,
  56                             (cd->__steps, cd->__data, NULL, NULL, NULL,
  57                              irreversible,
  58                              cd->__data[last_step].__outbuf == NULL ? 2 : 1,
  59                              0));
  60
  61       /* If the flush was successful clear the rest of the state.  */
  62       if (result == __GCONV_OK)
  63         for (size_t cnt = 0; cnt <= last_step; ++cnt)
  64           cd->__data[cnt].__invocation_counter = 0;
  65     }
  66   else
  67     {
  68       const unsigned char *last_start;
  69
  70       assert (outbuf != NULL && *outbuf != NULL);
  71
  72       do
  73         {
  74           last_start = *inbuf;
  75           result = DL_CALL_FCT (fct,
  76                                 (cd->__steps, cd->__data, inbuf, inbufend,
  77                                  NULL, irreversible, 0, 0));
  78         }
  79       while (result == __GCONV_EMPTY_INPUT && last_start != *inbuf
  80              && *inbuf + cd->__steps->__min_needed_from <= inbufend);
  81     }
  82
  83   if (outbuf != NULL && *outbuf != NULL)
  84     *outbuf = cd->__data[last_step].__outbuf;
  85
  86   return result;
  87 }