blob: 11a1e4764d4afeeedbd368bca3b18f4794aa0e40 [file] [log] [blame]
/* Convert UTF-16 string to UTF-8 string.
Copyright (C) 2002, 2006-2007, 2009-2019 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2002.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "unistr.h"
#define FUNC u16_to_u8
#define SRC_UNIT uint16_t
#define DST_UNIT uint8_t
#include <errno.h>
#include <stdlib.h>
#include <string.h>
DST_UNIT *
FUNC (const SRC_UNIT *s, size_t n, DST_UNIT *resultbuf, size_t *lengthp)
{
const SRC_UNIT *s_end = s + n;
/* Output string accumulator. */
DST_UNIT *result;
size_t allocated;
size_t length;
if (resultbuf != NULL)
{
result = resultbuf;
allocated = *lengthp;
}
else
{
result = NULL;
allocated = 0;
}
length = 0;
/* Invariants:
result is either == resultbuf or == NULL or malloc-allocated.
If length > 0, then result != NULL. */
while (s < s_end)
{
ucs4_t uc;
int count;
/* Fetch a Unicode character from the input string. */
count = u16_mbtoucr (&uc, s, s_end - s);
if (count < 0)
{
if (!(result == resultbuf || result == NULL))
free (result);
errno = EILSEQ;
return NULL;
}
s += count;
/* Store it in the output string. */
count = u8_uctomb (result + length, uc, allocated - length);
if (count == -1)
{
if (!(result == resultbuf || result == NULL))
free (result);
errno = EILSEQ;
return NULL;
}
if (count == -2)
{
DST_UNIT *memory;
allocated = (allocated > 0 ? 2 * allocated : 12);
if (length + 6 > allocated)
allocated = length + 6;
if (result == resultbuf || result == NULL)
memory = (DST_UNIT *) malloc (allocated * sizeof (DST_UNIT));
else
memory =
(DST_UNIT *) realloc (result, allocated * sizeof (DST_UNIT));
if (memory == NULL)
{
if (!(result == resultbuf || result == NULL))
free (result);
errno = ENOMEM;
return NULL;
}
if (result == resultbuf && length > 0)
memcpy ((char *) memory, (char *) result,
length * sizeof (DST_UNIT));
result = memory;
count = u8_uctomb (result + length, uc, allocated - length);
if (count < 0)
abort ();
}
length += count;
}
if (length == 0)
{
if (result == NULL)
{
/* Return a non-NULL value. NULL means error. */
result = (DST_UNIT *) malloc (1);
if (result == NULL)
{
errno = ENOMEM;
return NULL;
}
}
}
else if (result != resultbuf && length < allocated)
{
/* Shrink the allocated memory if possible. */
DST_UNIT *memory;
memory = (DST_UNIT *) realloc (result, length * sizeof (DST_UNIT));
if (memory != NULL)
result = memory;
}
*lengthp = length;
return result;
}