string_decoder: add support for CESU-8

Fixes #3217.
This commit is contained in:
koichik 2012-05-05 12:22:01 +09:00
parent eaf607e88b
commit ceb51ddaa1
2 changed files with 77 additions and 13 deletions

View File

@ -22,7 +22,7 @@
var StringDecoder = exports.StringDecoder = function(encoding) { var StringDecoder = exports.StringDecoder = function(encoding) {
this.encoding = (encoding || 'utf8').toLowerCase().replace(/[-_]/, ''); this.encoding = (encoding || 'utf8').toLowerCase().replace(/[-_]/, '');
if (this.encoding === 'utf8') { if (this.encoding === 'utf8') {
this.charBuffer = new Buffer(4); this.charBuffer = new Buffer(6);
this.charReceived = 0; this.charReceived = 0;
this.charLength = 0; this.charLength = 0;
} }
@ -36,16 +36,18 @@ StringDecoder.prototype.write = function(buffer) {
} }
var charStr = ''; var charStr = '';
var offset = 0;
// if our last write ended with an incomplete multibyte character // if our last write ended with an incomplete multibyte character
if (this.charLength) { while (this.charLength) {
// determine how many remaining bytes this buffer has to offer for this char // determine how many remaining bytes this buffer has to offer for this char
var i = (buffer.length >= this.charLength - this.charReceived) ? var i = (buffer.length >= this.charLength - this.charReceived) ?
this.charLength - this.charReceived : this.charLength - this.charReceived :
buffer.length; buffer.length;
// add the new bytes to the char buffer // add the new bytes to the char buffer
buffer.copy(this.charBuffer, this.charReceived, 0, i); buffer.copy(this.charBuffer, this.charReceived, offset, i);
this.charReceived += i; this.charReceived += (i - offset);
offset = i;
if (this.charReceived < this.charLength) { if (this.charReceived < this.charLength) {
// still not enough chars in this buffer? wait for more ... // still not enough chars in this buffer? wait for more ...
@ -54,6 +56,16 @@ StringDecoder.prototype.write = function(buffer) {
// get the character that was split // get the character that was split
charStr = this.charBuffer.slice(0, this.charLength).toString(); charStr = this.charBuffer.slice(0, this.charLength).toString();
// lead surrogate (D800-DBFF) is also the incomplete character
if (this.charLength === 3) {
var charCode = charStr.charCodeAt(0);
if (charCode >= 0xD800 && charCode <= 0xDBFF) {
charStr = '';
this.charLength += 3; // size of trail surrogate (DC00-DFFF)
continue;
}
}
this.charReceived = this.charLength = 0; this.charReceived = this.charLength = 0;
// if there are no more bytes in this buffer, just emit our char // if there are no more bytes in this buffer, just emit our char
@ -61,6 +73,7 @@ StringDecoder.prototype.write = function(buffer) {
// otherwise cut off the characters end from the beginning of this buffer // otherwise cut off the characters end from the beginning of this buffer
buffer = buffer.slice(i, buffer.length); buffer = buffer.slice(i, buffer.length);
break;
} }
@ -93,18 +106,26 @@ StringDecoder.prototype.write = function(buffer) {
} }
} }
if (!this.charLength) { var end = buffer.length;
// no incomplete char at the end of this buffer, emit the whole thing if (this.charLength) {
return charStr + buffer.toString(); // buffer the incomplete character bytes we got
buffer.copy(this.charBuffer, 0, buffer.length - i, buffer.length);
this.charReceived = i;
end -= i;
} }
// buffer the incomplete character bytes we got charStr += buffer.toString('utf8', 0, end);
buffer.copy(this.charBuffer, 0, buffer.length - i, buffer.length);
this.charReceived = i;
if (buffer.length - i > 0) { // lead surrogate (D800-DBFF) is also the incomplete character
// buffer had more bytes before the incomplete char, emit them end = charStr.length - 1;
return charStr + buffer.toString('utf8', 0, buffer.length - i); var charCode = charStr.charCodeAt(end);
if (charCode >= 0xD800 && charCode <= 0xDBFF) {
// CESU-8 represents each of Surrogate Pair by 3-bytes
this.charLength += 3
this.charReceived += 3
this.charBuffer.copy(this.charBuffer, 3, 0, 3);
this.charBuffer.write(charStr.charAt(end));
return charStr.substring(0, end);
} }
// or just emit the charStr // or just emit the charStr

View File

@ -46,6 +46,49 @@ s += decoder.write(buffer.slice(2, 3));
s += decoder.write(buffer.slice(3, 4)); s += decoder.write(buffer.slice(3, 4));
assert.ok(s.length > 0); assert.ok(s.length > 0);
// CESU-8
buffer = new Buffer('EDA0BDEDB18D', 'hex'); // THUMBS UP SIGN (in CESU-8)
var s = '';
s += decoder.write(buffer.slice(0, 1));
s += decoder.write(buffer.slice(1, 2));
s += decoder.write(buffer.slice(2, 3)); // complete lead surrogate
assert.equal(s, '');
s += decoder.write(buffer.slice(3, 4));
s += decoder.write(buffer.slice(4, 5));
s += decoder.write(buffer.slice(5, 6)); // complete trail surrogate
assert.equal(s, '\uD83D\uDC4D'); // THUMBS UP SIGN (in UTF-16)
var s = '';
s += decoder.write(buffer.slice(0, 2));
s += decoder.write(buffer.slice(2, 4)); // complete lead surrogate
assert.equal(s, '');
s += decoder.write(buffer.slice(4, 6)); // complete trail surrogate
assert.equal(s, '\uD83D\uDC4D'); // THUMBS UP SIGN (in UTF-16)
var s = '';
s += decoder.write(buffer.slice(0, 3)); // complete lead surrogate
assert.equal(s, '');
s += decoder.write(buffer.slice(3, 6)); // complete trail surrogate
assert.equal(s, '\uD83D\uDC4D'); // THUMBS UP SIGN (in UTF-16)
var s = '';
s += decoder.write(buffer.slice(0, 4)); // complete lead surrogate
assert.equal(s, '');
s += decoder.write(buffer.slice(4, 5));
s += decoder.write(buffer.slice(5, 6)); // complete trail surrogate
assert.equal(s, '\uD83D\uDC4D'); // THUMBS UP SIGN (in UTF-16)
var s = '';
s += decoder.write(buffer.slice(0, 5)); // complete lead surrogate
assert.equal(s, '');
s += decoder.write(buffer.slice(5, 6)); // complete trail surrogate
assert.equal(s, '\uD83D\uDC4D'); // THUMBS UP SIGN (in UTF-16)
var s = '';
s += decoder.write(buffer.slice(0, 6));
assert.equal(s, '\uD83D\uDC4D'); // THUMBS UP SIGN (in UTF-16)
// A mixed ascii and non-ascii string // A mixed ascii and non-ascii string
// Test stolen from deps/v8/test/cctest/test-strings.cc // Test stolen from deps/v8/test/cctest/test-strings.cc
// U+02E4 -> CB A4 // U+02E4 -> CB A4