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

   1 /* Conversion to UTF-8 from 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 uint8_t *
  33 u8_conv_from_encoding (const char *fromcode,
  34                        enum iconv_ilseq_handler handler,
  35                        const char *src, size_t srclen,
  36                        size_t *offsets,
  37                        uint8_t *resultbuf, size_t *lengthp)
  38 {
  39   if (STRCASEEQ (fromcode, "UTF-8", 'U','T','F','-','8',0,0,0,0))
  40     {
  41       /* Conversion from UTF-8 to UTF-8.  No need to go through iconv().  */
  42       uint8_t *result;
  43
  44       if (u8_check ((const uint8_t *) src, srclen))
  45         {
  46           errno = EILSEQ;
  47           return NULL;
  48         }
  49
  50       if (offsets != NULL)
  51         {
  52           size_t i;
  53
  54           for (i = 0; i < srclen; )
  55             {
  56               int count = u8_mblen ((const uint8_t *) src + i, srclen - i);
  57               /* We can rely on count > 0 because of the previous u8_check.  */
  58               if (count <= 0)
  59                 abort ();
  60               offsets[i] = i;
  61               i++;
  62               while (--count > 0)
  63                 offsets[i++] = (size_t)(-1);
  64             }
  65         }
  66
  67       /* Memory allocation.  */
  68       if (resultbuf != NULL && *lengthp >= srclen)
  69         result = resultbuf;
  70       else
  71         {
  72           result = (uint8_t *) malloc (srclen > 0 ? srclen : 1);
  73           if (result == NULL)
  74             {
  75               errno = ENOMEM;
  76               return NULL;
  77             }
  78         }
  79
  80       if (srclen > 0)
  81         memcpy ((char *) result, src, srclen);
  82       *lengthp = srclen;
  83       return result;
  84     }
  85   else
  86     {
  87       char *result = (char *) resultbuf;
  88       size_t length = *lengthp;
  89
  90       if (mem_iconveha (src, srclen, fromcode, "UTF-8", true, handler,
  91                         offsets, &result, &length) < 0)
  92         return NULL;
  93
  94       if (result == NULL) /* when (resultbuf == NULL && length == 0)  */
  95         {
  96           result = (char *) malloc (1);
  97           if (result == NULL)
  98             {
  99               errno = ENOMEM;
 100               return NULL;
 101             }
 102         }
 103       *lengthp = length;
 104       return (uint8_t *) result;
 105     }
 106 }