hare

commit 5d6c8071e375856f60d5ff741caf65b5a221e2f2
parent a0d9ef9d5132a1338dcfa6848f88e523517ec2c3
Author: Bor Grošelj Simić <bor.groseljsimic@telemach.net>
Date:   Tue,  9 Feb 2021 21:17:10 +0100

bytes/index.ha: fix a substring search bug

The substring search failed to find "aab" in "aaab". A test case was
added with this input (but in bytes).

Diffstat:
M
bytes/index.ha
 | 
21
+++++++++------------

1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/bytes/index.ha b/bytes/index.ha
@@ -16,18 +16,9 @@ fn index_byte(haystack: []u8, needle: u8) (size | void) = {
 };
 
 fn index_slice(haystack: []u8, needle: []u8) (size | void) = {
-	if (len(needle) > len(haystack)) {
-		return;
-	};
-	let i = 0z;
-	for (i < len(haystack)) {
-		let n = nequal(haystack[i..], needle);
-		if (n == len(needle)) {
+	for (let i = 0z; i + len(needle) <= len(haystack); i += 1z) {
+		if (equal(haystack[i..i + len(needle)], needle)) {
 			return i;
-		} else if (n != 0z) {
-			i += n;
-		} else {
-			i += 1z;
 		};
 	};
 };
@@ -35,7 +26,7 @@ fn index_slice(haystack: []u8, needle: []u8) (size | void) = {
 
 @test fn index() void = {
 	// Bytes
-	let a: [4]u8 = [1u8, 3u8, 3u8, 7u8];
+	const a: [4]u8 = [1u8, 3u8, 3u8, 7u8];
 	match (index(a, 7u8)) {
 		n: size => assert(n == 3z),
 		void => abort(),
@@ -62,4 +53,10 @@ fn index_slice(haystack: []u8, needle: []u8) (size | void) = {
 		size => abort(),
 		void => void,
 	};
+
+	const special: []u8 = [1u8, 1u8, 1u8, 2u8];
+	match (index(special, [1u8, 1u8, 2u8])) {
+		n: size => assert(n == 1z),
+		void => abort(),
+	};
 };