hare

commit c08cc7e751106913fe3c146f9091fb4b84ddc454
parent 1e28e8ac6853366424048307904de2ceed11522a
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sun,  7 Feb 2021 11:45:43 -0500

bytes, strings: add contains

Diffstat:
A
bytes/contains.ha
 | 
5
+++++
M
bytes/index.ha
 | 
42
+++++++++++++++++++++++++++++++++++++++++-
A
strings/contains.ha
 | 
15
+++++++++++++++

3 files changed, 61 insertions(+), 1 deletion(-)
diff --git a/bytes/contains.ha b/bytes/contains.ha
@@ -0,0 +1,5 @@
+// Returns true if a byte slice contains a byte or a sequence of bytes.
+export fn contains(haystack: []u8, needle: (u8 | []u8)) bool = match (needle) {
+	b: u8   => !(index_byte(haystack, b) is void),
+	b: []u8 => !(index_slice(haystack, b) is void),
+};
diff --git a/bytes/index.ha b/bytes/index.ha
@@ -1,6 +1,13 @@
 // Returns the offset of the first instance of 'needle' in a 'haystack' of
 // bytes, or void if it is not found.
-export fn index(haystack: []u8, needle: u8) (size | void) = {
+export fn index(haystack: []u8, needle: (u8 | []u8)) (size | void) = {
+	return match (needle) {
+		b: u8   => index_byte(haystack, b),
+		b: []u8 => index_slice(haystack, b),
+	};
+};
+
+fn index_byte(haystack: []u8, needle: u8) (size | void) = {
 	for (let i = 0z; i < len(haystack); i += 1z) {
 		if (haystack[i] == needle) {
 			return i;
@@ -8,7 +15,26 @@ export fn index(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)) {
+			return i;
+		} else if (n != 0z) {
+			i += n;
+		} else {
+			i += 1z;
+		};
+	};
+};
+
+
 @test fn index() void = {
+	// Bytes
 	let a: [4]u8 = [1u8, 3u8, 3u8, 7u8];
 	match (index(a, 7u8)) {
 		n: size => assert(n == 3z),
@@ -22,4 +48,18 @@ export fn index(haystack: []u8, needle: u8) (size | void) = {
 		size => abort(),
 		void => void,
 	};
+
+	// Slices
+	match (index(a, [3u8, 3u8])) {
+		n: size => assert(n == 1z),
+		void => abort(),
+	};
+	match (index(a, [])) {
+		n: size => assert(n == 0z),
+		void => abort(),
+	};
+	match(index(a, [4u8, 2u8])) {
+		size => abort(),
+		void => void,
+	};
 };
diff --git a/strings/contains.ha b/strings/contains.ha
@@ -0,0 +1,15 @@
+use bytes;
+use encoding::utf8;
+
+// Returns true if a string contains a rune or a sub-string.
+export fn contains(haystack: str, needle: (str | rune)) bool = match (needle) {
+	s: str  => bytes::contains(to_utf8(haystack), to_utf8(s)),
+	r: rune => bytes::contains(to_utf8(haystack), utf8::encode_rune(r)),
+};
+
+@test fn contains() void = {
+	assert(contains("hello world", "hello"));
+	assert(contains("hello world", "world"));
+	assert(contains("hello world", ""));
+	assert(!contains("hello world", "foobar"));
+};