80 lines
2.3 KiB
JavaScript
80 lines
2.3 KiB
JavaScript
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/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { isDict, isStream } from './primitives';
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import { DecodeStream } from './stream';
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import { Jbig2Image } from './jbig2';
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import { shadow } from '../shared/util';
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/**
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* For JBIG2's we use a library to decode these images and
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* the stream behaves like all the other DecodeStreams.
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*/
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var Jbig2Stream = (function Jbig2StreamClosure() {
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function Jbig2Stream(stream, maybeLength, dict, params) {
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this.stream = stream;
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this.maybeLength = maybeLength;
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this.dict = dict;
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this.params = params;
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DecodeStream.call(this, maybeLength);
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}
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Jbig2Stream.prototype = Object.create(DecodeStream.prototype);
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Object.defineProperty(Jbig2Stream.prototype, 'bytes', {
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get() {
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// If this.maybeLength is null, we'll get the entire stream.
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return shadow(this, 'bytes', this.stream.getBytes(this.maybeLength));
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},
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configurable: true,
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});
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Jbig2Stream.prototype.ensureBuffer = function(req) {
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if (this.bufferLength) {
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return;
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}
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var jbig2Image = new Jbig2Image();
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var chunks = [];
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if (isDict(this.params)) {
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var globalsStream = this.params.get('JBIG2Globals');
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if (isStream(globalsStream)) {
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var globals = globalsStream.getBytes();
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chunks.push({ data: globals, start: 0, end: globals.length, });
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}
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}
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chunks.push({ data: this.bytes, start: 0, end: this.bytes.length, });
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var data = jbig2Image.parseChunks(chunks);
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var dataLength = data.length;
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// JBIG2 had black as 1 and white as 0, inverting the colors
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for (var i = 0; i < dataLength; i++) {
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data[i] ^= 0xFF;
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}
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this.buffer = data;
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this.bufferLength = dataLength;
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this.eof = true;
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};
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return Jbig2Stream;
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})();
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export {
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Jbig2Stream,
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};
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