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/* Locale dependent memory area transformation for comparison.
Copyright (C) 2009-2022 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2009.
This file 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 2.1 of the
License, or (at your option) any later version.
This file 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 "amemxfrm.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
char *
amemxfrm (char *s, size_t n, char *resultbuf, size_t *lengthp)
{
/* Result accumulator. */
char *result;
size_t length;
size_t allocated;
char orig_sentinel;
/* Initial memory allocation. */
if (resultbuf != NULL && *lengthp > 0)
{
result = resultbuf;
allocated = *lengthp;
}
else
{
allocated = (n > 0 ? n : 1);
result = (char *) malloc (allocated);
if (result == NULL)
goto out_of_memory_2;
}
length = 0;
/* Add sentinel.byte. */
orig_sentinel = s[n];
s[n] = '\0';
/* Iterate through S, transforming each NUL terminated segment.
Accumulate the resulting transformed segments in result, separated by
NULs. */
{
const char *p_end = s + n + 1;
const char *p;
p = s;
for (;;)
{
/* Search next NUL byte. */
size_t l = strlen (p);
for (;;)
{
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 >= allocated - length)
{
/* Grow the result buffer. */
size_t new_allocated;
char *new_result;
new_allocated = length + 3 * l + 1;
if (new_allocated < 2 * allocated)
new_allocated = 2 * allocated;
if (new_allocated < 64)
new_allocated = 64;
if (result == resultbuf)
new_result = (char *) malloc (new_allocated);
else
new_result = (char *) realloc (result, new_allocated);
if (new_result != NULL)
{
allocated = new_allocated;
result = new_result;
}
}
errno = 0;
k = strxfrm (result + length, p, allocated - length);
if (errno != 0)
goto fail;
if (k >= allocated - length)
{
/* Grow the result buffer. */
size_t new_allocated;
char *new_result;
new_allocated = length + k + 1;
if (new_allocated < 2 * allocated)
new_allocated = 2 * allocated;
if (new_allocated < 64)
new_allocated = 64;
if (result == resultbuf)
new_result = (char *) malloc (new_allocated);
else
new_result = (char *) realloc (result, new_allocated);
if (new_result == NULL)
goto out_of_memory_1;
allocated = new_allocated;
result = new_result;
}
else
{
length += k;
break;
}
}
p = p + l + 1;
if (p == p_end)
break;
result[length] = '\0';
length++;
}
}
/* Shrink the allocated memory if possible.
It is not worth calling realloc when length + 1 == allocated; it would
save just one byte. */
if (result != resultbuf && length + 1 < allocated)
{
if ((length > 0 ? length : 1) <= *lengthp)
{
memcpy (resultbuf, result, length);
free (result);
result = resultbuf;
}
else
{
char *memory = (char *) realloc (result, length > 0 ? length : 1);
if (memory != NULL)
result = memory;
}
}
s[n] = orig_sentinel;
*lengthp = length;
return result;
fail:
if (result != resultbuf)
free (result);
s[n] = orig_sentinel;
return NULL;
out_of_memory_1:
if (result != resultbuf)
free (result);
s[n] = orig_sentinel;
out_of_memory_2:
errno = ENOMEM;
return NULL;
}
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