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-rw-r--r--lib/amemxfrm.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/lib/amemxfrm.c b/lib/amemxfrm.c
new file mode 100644
index 00000000..d3525d98
--- /dev/null
+++ b/lib/amemxfrm.c
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+/* Locale dependent memory area transformation for comparison.
+ Copyright (C) 2009-2015 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2009.
+
+ 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 <http://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:
+ {
+ int saved_errno = errno;
+ if (result != resultbuf)
+ free (result);
+ s[n] = orig_sentinel;
+ errno = saved_errno;
+ return NULL;
+ }
+
+ out_of_memory_1:
+ if (result != resultbuf)
+ free (result);
+ s[n] = orig_sentinel;
+ out_of_memory_2:
+ errno = ENOMEM;
+ return NULL;
+}