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GUACAMOLE-896: Add JavaScript UTF-8 parser implementation.

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This commit is contained in:
Michael Jumper
2022-02-11 16:33:02 -08:00
parent a97404b6ad
commit f559f5ca70
2 changed files with 134 additions and 93 deletions
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101
guacamole-common-js/src/main/webapp/modules/StringReader.js
View File

@@ -38,6 +38,13 @@ Guacamole.StringReader = function(stream) {
*/
var guac_reader = this;
/**
* Parser for received UTF-8 data.
*
* @type {!Guacamole.UTF8Parser}
*/
var utf8Parser = new Guacamole.UTF8Parser();
/**
* Wrapped Guacamole.ArrayBufferReader.
*
@@ -46,103 +53,11 @@ Guacamole.StringReader = function(stream) {
*/
var array_reader = new Guacamole.ArrayBufferReader(stream);
/**
* The number of bytes remaining for the current codepoint.
*
* @private
* @type {!number}
*/
var bytes_remaining = 0;
/**
* The current codepoint value, as calculated from bytes read so far.
*
* @private
* @type {!number}
*/
var codepoint = 0;
/**
* Decodes the given UTF-8 data into a Unicode string. The data may end in
* the middle of a multibyte character.
*
* @private
* @param {!ArrayBuffer} buffer
* Arbitrary UTF-8 data.
*
* @return {!string}
* A decoded Unicode string.
*/
function __decode_utf8(buffer) {
var text = "";
var bytes = new Uint8Array(buffer);
for (var i=0; i<bytes.length; i++) {
// Get current byte
var value = bytes[i];
// Start new codepoint if nothing yet read
if (bytes_remaining === 0) {
// 1 byte (0xxxxxxx)
if ((value | 0x7F) === 0x7F)
text += String.fromCharCode(value);
// 2 byte (110xxxxx)
else if ((value | 0x1F) === 0xDF) {
codepoint = value & 0x1F;
bytes_remaining = 1;
}
// 3 byte (1110xxxx)
else if ((value | 0x0F )=== 0xEF) {
codepoint = value & 0x0F;
bytes_remaining = 2;
}
// 4 byte (11110xxx)
else if ((value | 0x07) === 0xF7) {
codepoint = value & 0x07;
bytes_remaining = 3;
}
// Invalid byte
else
text += "\uFFFD";
}
// Continue existing codepoint (10xxxxxx)
else if ((value | 0x3F) === 0xBF) {
codepoint = (codepoint << 6) | (value & 0x3F);
bytes_remaining--;
// Write codepoint if finished
if (bytes_remaining === 0)
text += String.fromCharCode(codepoint);
}
// Invalid byte
else {
bytes_remaining = 0;
text += "\uFFFD";
}
}
return text;
}
// Receive blobs as strings
array_reader.ondata = function(buffer) {
// Decode UTF-8
var text = __decode_utf8(buffer);
var text = utf8Parser.decode(buffer);
// Call handler, if present
if (guac_reader.ontext)

126
guacamole-common-js/src/main/webapp/modules/UTF8Parser.js Normal file
View File

@@ -0,0 +1,126 @@
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
var Guacamole = Guacamole || {};
/**
* Parser that decodes UTF-8 text from a series of provided ArrayBuffers.
* Multi-byte characters that continue from one buffer to the next are handled
* correctly.
*
* @constructor
*/
Guacamole.UTF8Parser = function UTF8Parser() {
/**
* The number of bytes remaining for the current codepoint.
*
* @private
* @type {!number}
*/
var bytesRemaining = 0;
/**
* The current codepoint value, as calculated from bytes read so far.
*
* @private
* @type {!number}
*/
var codepoint = 0;
/**
* Decodes the given UTF-8 data into a Unicode string, returning a string
* containing all complete UTF-8 characters within the provided data. The
* data may end in the middle of a multi-byte character, in which case the
* complete character will be returned from a later call to decode() after
* enough bytes have been provided.
*
* @private
* @param {!ArrayBuffer} buffer
* Arbitrary UTF-8 data.
*
* @return {!string}
* The decoded Unicode string.
*/
this.decode = function decode(buffer) {
var text = '';
var bytes = new Uint8Array(buffer);
for (var i=0; i<bytes.length; i++) {
// Get current byte
var value = bytes[i];
// Start new codepoint if nothing yet read
if (bytesRemaining === 0) {
// 1 byte (0xxxxxxx)
if ((value | 0x7F) === 0x7F)
text += String.fromCharCode(value);
// 2 byte (110xxxxx)
else if ((value | 0x1F) === 0xDF) {
codepoint = value & 0x1F;
bytesRemaining = 1;
}
// 3 byte (1110xxxx)
else if ((value | 0x0F )=== 0xEF) {
codepoint = value & 0x0F;
bytesRemaining = 2;
}
// 4 byte (11110xxx)
else if ((value | 0x07) === 0xF7) {
codepoint = value & 0x07;
bytesRemaining = 3;
}
// Invalid byte
else
text += '\uFFFD';
}
// Continue existing codepoint (10xxxxxx)
else if ((value | 0x3F) === 0xBF) {
codepoint = (codepoint << 6) | (value & 0x3F);
bytesRemaining--;
// Write codepoint if finished
if (bytesRemaining === 0)
text += String.fromCharCode(codepoint);
}
// Invalid byte
else {
bytesRemaining = 0;
text += '\uFFFD';
}
}
return text;
};
};