root/maint/gnulib/lib/unistr/u16-to-u32.c

/* */

DEFINITIONS

1. FUNC

   1 /* Convert UTF-16 string to UTF-32 string.
   2    Copyright (C) 2002, 2006-2007, 2009-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2002.
   4 
   5    This file is free software.
   6    It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   7    You can redistribute it and/or modify it under either
   8      - the terms of the GNU Lesser General Public License as published
   9        by the Free Software Foundation; either version 3, or (at your
  10        option) any later version, or
  11      - the terms of the GNU General Public License as published by the
  12        Free Software Foundation; either version 2, or (at your option)
  13        any later version, or
  14      - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  15 
  16    This file is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Lesser General Public License and the GNU General Public License
  20    for more details.
  21 
  22    You should have received a copy of the GNU Lesser General Public
  23    License and of the GNU General Public License along with this
  24    program.  If not, see <https://www.gnu.org/licenses/>.  */
  25 
  26 #include <config.h>
  27 
  28 /* Specification.  */
  29 #include "unistr.h"
  30 
  31 #define FUNC u16_to_u32
  32 #define SRC_UNIT uint16_t
  33 #define DST_UNIT uint32_t
  34 
  35 #include <errno.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 
  39 DST_UNIT *
  40 FUNC (const SRC_UNIT *s, size_t n, DST_UNIT *resultbuf, size_t *lengthp)
     /*  */
  41 {
  42   const SRC_UNIT *s_end = s + n;
  43   /* Output string accumulator.  */
  44   DST_UNIT *result;
  45   size_t allocated;
  46   size_t length;
  47 
  48   if (resultbuf != NULL)
  49     {
  50       result = resultbuf;
  51       allocated = *lengthp;
  52     }
  53   else
  54     {
  55       result = NULL;
  56       allocated = 0;
  57     }
  58   length = 0;
  59   /* Invariants:
  60      result is either == resultbuf or == NULL or malloc-allocated.
  61      If length > 0, then result != NULL.  */
  62 
  63   while (s < s_end)
  64     {
  65       ucs4_t uc;
  66       int count;
  67 
  68       /* Fetch a Unicode character from the input string.  */
  69       count = u16_mbtoucr (&uc, s, s_end - s);
  70       if (count < 0)
  71         {
  72           if (!(result == resultbuf || result == NULL))
  73             free (result);
  74           errno = EILSEQ;
  75           return NULL;
  76         }
  77       s += count;
  78 
  79       /* Store it in the output string.  */
  80       if (length + 1 > allocated)
  81         {
  82           DST_UNIT *memory;
  83 
  84           allocated = (allocated > 0 ? 2 * allocated : 12);
  85           if (length + 1 > allocated)
  86             allocated = length + 1;
  87           if (result == resultbuf || result == NULL)
  88             memory = (DST_UNIT *) malloc (allocated * sizeof (DST_UNIT));
  89           else
  90             memory =
  91               (DST_UNIT *) realloc (result, allocated * sizeof (DST_UNIT));
  92 
  93           if (memory == NULL)
  94             {
  95               if (!(result == resultbuf || result == NULL))
  96                 free (result);
  97               errno = ENOMEM;
  98               return NULL;
  99             }
 100           if (result == resultbuf && length > 0)
 101             memcpy ((char *) memory, (char *) result,
 102                     length * sizeof (DST_UNIT));
 103           result = memory;
 104         }
 105       result[length++] = uc;
 106     }
 107 
 108   if (length == 0)
 109     {
 110       if (result == NULL)
 111         {
 112           /* Return a non-NULL value.  NULL means error.  */
 113           result = (DST_UNIT *) malloc (1);
 114           if (result == NULL)
 115             {
 116               errno = ENOMEM;
 117               return NULL;
 118             }
 119         }
 120     }
 121   else if (result != resultbuf && length < allocated)
 122     {
 123       /* Shrink the allocated memory if possible.  */
 124       DST_UNIT *memory;
 125 
 126       memory = (DST_UNIT *) realloc (result, length * sizeof (DST_UNIT));
 127       if (memory != NULL)
 128         result = memory;
 129     }
 130 
 131   *lengthp = length;
 132   return result;
 133 }

/* */