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-rw-r--r--mysys/my_memmem.c84
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diff --git a/mysys/my_memmem.c b/mysys/my_memmem.c
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+/* Copyright (c) 2000, 2006, 2007 MySQL AB
+ Use is subject to license terms
+
+ 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; version 2 of the License.
+
+ 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, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+#include <my_global.h>
+#include <m_string.h>
+
+/*
+ my_memmem, port of a GNU extension.
+
+ Returns a pointer to the beginning of the substring, needle, or NULL if the
+ substring is not found in haystack.
+*/
+
+void *my_memmem(const void *haystack, size_t haystacklen,
+ const void *needle, size_t needlelen)
+{
+ const unsigned char *cursor;
+ const unsigned char *last_possible_needle_location =
+ (unsigned char *)haystack + haystacklen - needlelen;
+
+ /* Easy answers */
+ if (needlelen > haystacklen) return(NULL);
+ if (needle == NULL) return(NULL);
+ if (haystack == NULL) return(NULL);
+ if (needlelen == 0) return(NULL);
+ if (haystacklen == 0) return(NULL);
+
+ for (cursor = haystack; cursor <= last_possible_needle_location; cursor++) {
+ if (memcmp(needle, cursor, needlelen) == 0) {
+ return((void *) cursor);
+ }
+ }
+ return(NULL);
+}
+
+
+
+#ifdef MAIN
+#include <assert.h>
+
+int main(int argc, char *argv[]) {
+ char haystack[10], needle[3];
+
+ memmove(haystack, "0123456789", 10);
+
+ memmove(needle, "no", 2);
+ assert(my_memmem(haystack, 10, needle, 2) == NULL);
+
+ memmove(needle, "345", 3);
+ assert(my_memmem(haystack, 10, needle, 3) != NULL);
+
+ memmove(needle, "789", 3);
+ assert(my_memmem(haystack, 10, needle, 3) != NULL);
+ assert(my_memmem(haystack, 9, needle, 3) == NULL);
+
+ memmove(needle, "012", 3);
+ assert(my_memmem(haystack, 10, needle, 3) != NULL);
+ assert(my_memmem(NULL, 10, needle, 3) == NULL);
+
+ assert(my_memmem(NULL, 10, needle, 3) == NULL);
+ assert(my_memmem(haystack, 0, needle, 3) == NULL);
+ assert(my_memmem(haystack, 10, NULL, 3) == NULL);
+ assert(my_memmem(haystack, 10, needle, 0) == NULL);
+
+ assert(my_memmem(haystack, 1, needle, 3) == NULL);
+
+ printf("success\n");
+ return(0);
+}
+
+#endif