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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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