lib/uniconv/u8-conv-to-enc.c

   1 /* Conversion from UTF-8 to legacy encodings.
   2    Copyright (C) 2002, 2006-2007, 2009-2020 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify it
   5    under the terms of the GNU Lesser General Public License as published
   6    by the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include "uniconv.h"
  23
  24 #include <errno.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include "c-strcaseeq.h"
  29 #include "striconveha.h"
  30 #include "unistr.h"
  31
  32 char *
  33 u8_conv_to_encoding (const char *tocode,
  34                      enum iconv_ilseq_handler handler,
  35                      const uint8_t *src, size_t srclen,
  36                      size_t *offsets,
  37                      char *resultbuf, size_t *lengthp)
  38 {
  39   if (STRCASEEQ (tocode, "UTF-8", 'U','T','F','-','8',0,0,0,0))
  40     {
  41       char *result;
  42
  43       /* Conversion from UTF-8 to UTF-8.  No need to go through iconv().  */
  44       if (u8_check (src, srclen))
  45         {
  46           errno = EILSEQ;
  47           return NULL;
  48         }
  49
  50       /* Memory allocation.  */
  51       if (resultbuf != NULL && *lengthp >= srclen)
  52         result = resultbuf;
  53       else
  54         {
  55           result = (char *) malloc (srclen > 0 ? srclen : 1);
  56           if (result == NULL)
  57             {
  58               errno = ENOMEM;
  59               return NULL;
  60             }
  61         }
  62
  63       if (srclen > 0)
  64         memcpy (result, (const char *) src, srclen);
  65       *lengthp = srclen;
  66       return result;
  67     }
  68   else
  69     {
  70       char *result = resultbuf;
  71       size_t length = *lengthp;
  72
  73       if (mem_iconveha ((const char *) src, srclen,
  74                         "UTF-8", tocode,
  75                         handler == iconveh_question_mark, handler,
  76                         offsets, &result, &length) < 0)
  77         return NULL;
  78
  79       if (result == NULL) /* when (resultbuf == NULL && length == 0)  */
  80         {
  81           result = (char *) malloc (1);
  82           if (result == NULL)
  83             {
  84               errno = ENOMEM;
  85               return NULL;
  86             }
  87         }
  88       *lengthp = length;
  89       return result;
  90     }
  91 }