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/* Locale dependent string transformation for comparison.
Copyright (C) 2010-2023 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2010.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "astrxfrm.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
char *
astrxfrm (const char *s, char *resultbuf, size_t *lengthp)
{
char tmpbuf[4000];
char *result; /* either == resultbuf or == tmpbuf or freshly allocated
or NULL. */
size_t allocated; /* number of bytes allocated at result */
size_t length;
if (resultbuf != NULL)
{
result = resultbuf;
allocated = *lengthp;
}
else
{
result = NULL;
allocated = 0;
}
{
size_t l = strlen (s);
size_t k;
/* A call to strxfrm costs about 20 times more than a call to strdup of
the result. Therefore it is worth to try to avoid calling strxfrm
more than once on a given string, by making enough room before calling
strxfrm. The size of the strxfrm result, k, is likely to be between
l and 3 * l. */
if (3 * l + 1 > allocated)
{
/* Grow the result buffer. */
if (3 * l + 1 <= sizeof (tmpbuf))
{
result = tmpbuf;
allocated = sizeof (tmpbuf);
}
else
{
size_t new_allocated;
char *new_result;
new_allocated = 3 * l + 1;
if (new_allocated < 2 * allocated)
new_allocated = 2 * allocated;
new_result = (char *) malloc (new_allocated);
if (new_result != NULL)
{
allocated = new_allocated;
result = new_result;
}
}
}
errno = 0;
k = strxfrm (result, s, allocated);
if (errno != 0)
goto fail;
if (k >= allocated)
{
/* Grow the result buffer. */
if (result != resultbuf && result != tmpbuf)
free (result);
if (k + 1 <= sizeof (tmpbuf))
{
result = tmpbuf;
allocated = sizeof (tmpbuf);
}
else
{
size_t new_allocated;
char *new_result;
new_allocated = k + 1;
new_result = (char *) malloc (new_allocated);
if (new_result == NULL)
goto out_of_memory;
allocated = new_allocated;
result = new_result;
}
/* Here k < allocated. */
/* Try again. */
errno = 0;
if (strxfrm (result, s, allocated) != k)
/* strxfrm() is not producing reproducible results. */
abort ();
if (errno != 0)
goto fail;
}
/* Verify that strxfrm() has NUL-terminated the result. */
if (result[k] != '\0')
abort ();
length = k + 1;
}
/* Here length > 0. */
if (result == tmpbuf)
{
if (resultbuf != NULL && length <= *lengthp)
{
memcpy (resultbuf, result, length);
result = resultbuf;
}
else
{
char *memory = (char *) malloc (length);
if (memory == NULL)
goto out_of_memory;
memcpy (memory, result, length);
result = memory;
}
}
else
{
/* Shrink the allocated memory if possible. */
if (result != resultbuf && length < allocated)
{
if (length <= *lengthp)
{
memcpy (resultbuf, result, length);
free (result);
result = resultbuf;
}
else
{
char *memory = (char *) realloc (result, length);
if (memory != NULL)
{
memcpy (memory, result, length);
result = memory;
}
}
}
}
*lengthp = length;
return result;
fail:
if (result != resultbuf && result != tmpbuf)
free (result);
return NULL;
out_of_memory:
errno = ENOMEM;
return NULL;
}
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