[Fix] write until an error

ljharb · ljharb · commit eb8d6c4e59d1 · 2024-07-08T11:04:42.000-07:00
Per tc39/test262#4133 / tc39/proposal-arraybuffer-base64#60 / tc39/proposal-arraybuffer-base64#58
diff --git a/Uint8Array.prototype.setFromBase64/implementation.js b/Uint8Array.prototype.setFromBase64/implementation.js
@@ -64,21 +64,21 @@ module.exports = function setFromBase64(string) {
 
 	var result = FromBase64(string, alphabet, lastChunkHandling, byteLength); // step 14
 
-	if (result['[[Error]]']) { // step 15
-		throw result['[[Error]]']; // step 15.a
-	}
-
-	var bytes = result['[[Bytes]]']; // step 16
+	var bytes = result['[[Bytes]]']; // step 15
 
-	var written = bytes.length; // step 17
+	var written = bytes.length; // step 16
 
-	// 18. NOTE: FromBase64 does not invoke any user code, so the ArrayBuffer backing into cannot have been detached or shrunk.
+	// 17. NOTE: FromBase64 does not invoke any user code, so the ArrayBuffer backing into cannot have been detached or shrunk.
 
 	if (written > byteLength) {
 		throw new $TypeError('Assertion failed: written is not <= byteLength'); // step 19
 	}
 
-	SetUint8ArrayBytes(into, bytes); // step 20
+	SetUint8ArrayBytes(into, bytes); // step 19
+
+	if (result['[[Error]]']) { // step 20
+		throw result['[[Error]]']; // step 20.a
+	}
 
 	var offset = typedArrayByteOffset(into); // step 21
 
diff --git a/Uint8Array.prototype.setFromHex/implementation.js b/Uint8Array.prototype.setFromHex/implementation.js
@@ -36,21 +36,21 @@ module.exports = function setFromHex(string) {
 
 	var result = FromHex(string, byteLength); // step 7
 
-	if (result['[[Error]]']) { // step 8
-		throw result['[[Error]]']; // step 8.a
-	}
-
-	var bytes = result['[[Bytes]]']; // step 9
+	var bytes = result['[[Bytes]]']; // step 8
 
-	var written = bytes.length; // step 10
+	var written = bytes.length; // step 9
 
-	// 11. NOTE: FromHex does not invoke any user code, so the ArrayBuffer backing into cannot have been detached or shrunk.
+	// 10. NOTE: FromHex does not invoke any user code, so the ArrayBuffer backing into cannot have been detached or shrunk.
 
 	if (written > byteLength) {
-		throw new $TypeError('Assertion failed: written is not <= byteLength'); // step 12
+		throw new $TypeError('Assertion failed: written is not <= byteLength'); // step 11
 	}
 
-	SetUint8ArrayBytes(into, bytes); // step 13
+	SetUint8ArrayBytes(into, bytes); // step 12
+
+	if (result['[[Error]]']) { // step 13
+		throw result['[[Error]]']; // step 13.a
+	}
 
 	// var resultObject = {}; // step 14 // OrdinaryObjectCreate(%Object.prototype%)
 	// CreateDataPropertyOrThrow(resultObject, 'read', result['[[Read]]']); // step 15
diff --git a/aos/FromHex.js b/aos/FromHex.js
@@ -31,26 +31,38 @@ module.exports = function FromHex(string) {
 
 	var length = string.length; // step 2
 
-	if (modulo(length, 2) !== 0) {
-		throw new $SyntaxError('string should be an even number of characters'); // step 3
-	}
+	var bytes = []; // step 3
 
-	var bytes = []; // step 4
+	var read = 0; // step 4
 
-	var index = 0; // step 5
+	if (modulo(length, 2) !== 0) { // step 5
+		return {
+			'[[Read]]': read,
+			'[[Bytes]]': bytes,
+			'[[Error]]': new $SyntaxError('string should be an even number of characters')
+		};
+	}
 
-	while (index < length && bytes.length < maxLength) { // step 6
-		var hexits = substring(string, index, index + 2); // step 6.a
+	while (read < length && bytes.length < maxLength) { // step 6
+		var hexits = substring(string, read, read + 2); // step 6.a
 
-		if (!isHexDigit(hexits)) {
-			throw new $SyntaxError('string should only contain hex characters'); // step 6.b
+		if (!isHexDigit(hexits)) { // step 6.b
+			return {
+				'[[Read]]': read,
+				'[[Bytes]]': bytes,
+				'[[Error]]': new $SyntaxError('string should only contain hex characters')
+			};
 		}
 
-		index += 2; // step 6.c
+		read += 2; // step 6.c
 
 		var byte = $parseInt(hexits, 16); // step 6.d
 
 		$push(bytes, byte); // step 6.e
 	}
-	return { '[[Read]]': index, '[[Bytes]]': bytes }; // step 7
+	return {
+		'[[Read]]': read,
+		'[[Bytes]]': bytes,
+		'[[Error]]': null
+	}; // step 7
 };
diff --git a/test/Uint8Array.prototype.setFromBase64.js b/test/Uint8Array.prototype.setFromBase64.js
@@ -574,6 +574,46 @@ module.exports = {
 				s2t.end();
 			});
 
+			st.test('test262: test/built-ins/Uint8Array/prototype/setFromBase64/writes-up-to-error', function (s2t) {
+				var target = new Uint8Array([255, 255, 255, 255, 255]);
+				s2t['throws'](
+					function () { method(target, 'MjYyZm.9v'); },
+					SyntaxError,
+					'illegal character in second chunk'
+				);
+				s2t.deepEqual(
+					target,
+					new Uint8Array([50, 54, 50, 255, 255]),
+					'decoding from MjYyZm.9v should only write the valid chunks'
+				);
+
+				var target2 = new Uint8Array([255, 255, 255, 255, 255]);
+				s2t['throws'](
+					function () { method(target2, 'MjYyZg', { lastChunkHandling: 'strict' }); },
+					SyntaxError,
+					'padding omitted with lastChunkHandling: strict'
+				);
+				s2t.deepEqual(
+					target2,
+					new Uint8Array([50, 54, 50, 255, 255]),
+					'decoding from MjYyZg should only write the valid chunks'
+				);
+
+				var target3 = new Uint8Array([255, 255, 255, 255, 255]);
+				s2t['throws'](
+					function () { method(target3, 'MjYyZg==='); },
+					SyntaxError,
+					'extra characters after padding'
+				);
+				s2t.deepEqual(
+					target3,
+					new Uint8Array([50, 54, 50, 255, 255]),
+					'decoding from MjYyZg=== should not write the last chunk because it has extra padding'
+				);
+
+				s2t.end();
+			});
+
 			var illegal = [
 				'Zm.9v',
 				'Zm9v^',
diff --git a/test/Uint8Array.prototype.setFromHex.js b/test/Uint8Array.prototype.setFromHex.js
@@ -181,6 +181,26 @@ module.exports = {
 				s2t.end();
 			});
 
+			st.test('test262: test/built-ins/Uint8Array/prototype/setFromHex/writes-up-to-error', function (s2t) {
+				['aaa ', 'aaag'].forEach(function (value) {
+					var target = new Uint8Array([255, 255, 255, 255, 255]);
+					s2t['throws'](
+						function () { method(target, value); },
+						SyntaxError
+					);
+					s2t.deepEqual(target, new Uint8Array([170, 255, 255, 255, 255]), 'decoding from ' + value);
+				});
+
+				var target = new Uint8Array([255, 255, 255, 255, 255]);
+				s2t['throws'](
+					function () { method(target, 'aaa'); },
+					SyntaxError
+				);
+				s2t.deepEqual(target, new Uint8Array([255, 255, 255, 255, 255]), 'when length is odd no data is written');
+
+				s2t.end();
+			});
+
 			st.end();
 		});
 	},
diff --git a/test/Uint8Array.prototype.toBase64.js b/test/Uint8Array.prototype.toBase64.js
@@ -225,6 +225,25 @@ module.exports = {
 				s2t.end();
 			});
 
+			st.test('test262: test/built-ins/Uint8Array/prototype/toBase64/omit-padding', function (s2t) {
+				s2t.equal(method(new Uint8Array([199, 239])), 'x+8=');
+				s2t.equal(method(new Uint8Array([199, 239]), { omitPadding: false }), 'x+8=');
+				s2t.equal(method(new Uint8Array([199, 239]), { omitPadding: true }), 'x+8');
+				s2t.equal(method(new Uint8Array([255]), { omitPadding: true }), '/w');
+
+				// works with base64url alphabet
+				s2t.equal(method(new Uint8Array([199, 239]), { alphabet: 'base64url' }), 'x-8=');
+				s2t.equal(method(new Uint8Array([199, 239]), { alphabet: 'base64url', omitPadding: false }), 'x-8=');
+				s2t.equal(method(new Uint8Array([199, 239]), { alphabet: 'base64url', omitPadding: true }), 'x-8');
+				s2t.equal(method(new Uint8Array([255]), { alphabet: 'base64url', omitPadding: true }), '_w');
+
+				// performs ToBoolean on the argument
+				s2t.equal(method(new Uint8Array([255]), { omitPadding: 0 }), '/w==');
+				s2t.equal(method(new Uint8Array([255]), { omitPadding: 1 }), '/w');
+
+				s2t.end();
+			});
+
 			// standard test vectors from https://datatracker.ietf.org/doc/html/rfc4648#section-10
 			st.equal(method(new Uint8Array([])), '');
 			st.equal(method(new Uint8Array([102])), 'Zg==');
