1 files changed, 39 insertions, 0 deletions
diff --git a/memreqlen.c b/memreqlen.c
new file mode 100644
index 0000000..c276b8d
--- /dev/null
+++ b/memreqlen.c
@@ -0,0 +1,39 @@
+/* See LICENSE file for copyright and license details. */
+#include "libsimple.h"
+#ifndef TEST
+
+
+size_t
+libsimple_memreqlen(const void *a_, size_t n, const void *b_, size_t m)
+{
+	const char *a = &((char *)a_)[n], *b = &((char *)b_)[m];
+	size_t i = 0, len = n < m ? n : m;
+	for (; i < len && *--a == *--b; i++);
+	return i;
+}
+
+
+#else
+#include "test.h"
+
+int
+main(void)
+{
+	char s[] = "abcdefgh", t[] = "abcdefgh";
+	size_t i, j;
+	assert(libsimple_memreqlen("x", 0, "x", 0) == 0);
+	assert(libsimple_memreqlen("x", 1, "x", 0) == 0);
+	assert(libsimple_memreqlen("x", 1, "y", 1) == 0);
+	assert(libsimple_memreqlen("y", 0, "y", 1) == 0);
+	for (i = 0; i <= 8; i++) {
+		for (j = 0; j <= 8; j++) {
+			assert(libsimple_memreqlen(&s[i], 8 - i, &t[j], 8 - j) == 8 - (i > j ? i : j));
+			assert(libsimple_memreqlen(s, i, t, j) == (i == j ? i : 0));
+		}
+	}
+	assert(libsimple_memreqlen("abc", 3, "ABC", 3) == 0);
+	assert(libsimple_memreqlen("123", 3, "123", 3) == 3);
+	return 0;
+}
+
+#endif