hare

commit 1e28e8ac6853366424048307904de2ceed11522a
parent 5a92722a862ff8afa85a5be830910f1e02bd5fbe
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sun,  7 Feb 2021 11:20:05 -0500

strings: add has_prefix, has_suffix

Diffstat:
A
strings/suffix.ha
 | 
48
++++++++++++++++++++++++++++++++++++++++++++++++
M
strings/tokenize.ha
 | 
2
+-

2 files changed, 49 insertions(+), 1 deletion(-)
diff --git a/strings/suffix.ha b/strings/suffix.ha
@@ -0,0 +1,48 @@
+// Returns true if 'in' has the given prefix.
+export fn has_prefix(in: str, prefix: str) bool = {
+	let a = to_utf8(in), b = to_utf8(prefix);
+	if (len(a) < len(b)) {
+		return false;
+	};
+	for (let i = 0z; i < len(b); i += 1z) {
+		if (a[i] != b[i]) {
+			return false;
+		};
+	};
+	return true;
+};
+
+@test fn prefix() void = {
+	assert(has_prefix("abcde", "abc"));
+	assert(has_prefix("abcde", "abcde"));
+	assert(has_prefix("abcde", ""));
+	assert(has_prefix("", ""));
+	assert(!has_prefix("abcde", "cde"));
+	assert(!has_prefix("abcde", "abcdefg"));
+	assert(!has_prefix("", "abc"));
+};
+
+// Returns true if 'in' has the given prefix.
+export fn has_suffix(in: str, suff: str) bool = {
+	let a = to_utf8(in), b = to_utf8(suff);
+	if (len(a) < len(b)) {
+		return false;
+	};
+	for (let i = 0z; i < len(b); i += 1z) {
+		if (a[len(a) - len(b) + i] != b[i]) {
+			return false;
+		};
+	};
+	return true;
+};
+
+@test fn suffix() void = {
+	assert(has_suffix("abcde", "cde"));
+	assert(has_suffix("abcde", "abcde"));
+	assert(has_suffix("abcde", ""));
+	assert(has_suffix("", ""));
+	assert(has_suffix("abcde", ""));
+	assert(!has_suffix("abcde", "abc"));
+	assert(!has_suffix("abcde", "fabcde"));
+	assert(!has_suffix("", "abc"));
+};
diff --git a/strings/tokenize.ha b/strings/tokenize.ha
@@ -2,7 +2,7 @@ use bytes;
 use types;
 
 // The state for a tokenizer.
-type tokenizer = bytes::tokenizer;
+export type tokenizer = bytes::tokenizer;
 
 // Returns a tokenizer which yields sub-strings tokenized by a delimiter.
 //