1 files changed, 65 insertions, 0 deletions
diff --git a/mysys/my_memmem.c b/mysys/my_memmem.c
new file mode 100644
index 00000000000..3a71d39c262
--- /dev/null
+++ b/mysys/my_memmem.c
@@ -0,0 +1,65 @@
+#include "my_base.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 void *cursor;
+  const void *last_possible_needle_location = 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