Add strn[case]eqlen

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 45 insertions, 0 deletions

diff --git a/strneqlen.c b/strneqlen.c
new file mode 100644
index 0000000..5ef50e3
--- /dev/null
+++ b/strneqlen.c
@@ -0,0 +1,45 @@
+/* See LICENSE file for copyright and license details. */
+#include "libsimple.h"
+#ifndef TEST
+
+
+size_t
+libsimple_strneqlen(const char *a, const char *b, size_t n)
+{
+	size_t i = 0;
+	for (; i < n && a[i] && a[i] == b[i]; i++);
+	return i;
+}
+
+
+#else
+#include "test.h"
+
+int
+main(void)
+{
+	char s[] = "abcdefgh", t[] = "abcdefgh";
+	size_t i, j, n;
+	for (n = 0; n < 10; n++) {
+		assert(libsimple_strneqlen("", "", n) == 0);
+		assert(libsimple_strneqlen("x", "", n) == 0);
+		assert(libsimple_strneqlen("x", "y", n) == 0);
+		assert(libsimple_strneqlen("", "y", n) == 0);
+		assert(libsimple_strneqlen("abc", "ABC", n) == 0);
+		assert(libsimple_strneqlen("ABC", "abc", n) == 0);
+		assert(libsimple_strneqlen("ABC", "ABC", n) == MIN(n, 3));
+		assert(libsimple_strneqlen("123", "123", n) == MIN(n, 3));
+		for (i = 0; i <= 8; i++) {
+			for (j = 0; j <= 8; j++) {
+				assert(libsimple_strneqlen(&s[i], &t[j], n) == MIN(i == j ? 8 - i : 0, n));
+				s[i] = t[j] = '\0';
+				assert(libsimple_strneqlen(s, t, n) == MIN(i < j ? i : j, n));
+				s[i] = "abcdefgh"[i];
+				t[j] = "abcdefgh"[j];
+			}
+		}
+	}
+	return 0;
+}
+
+#endif