1062 lines
38 KiB
JavaScript
1062 lines
38 KiB
JavaScript
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
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'use strict';
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var Jbig2Image = (function Jbig2ImageClosure() {
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// Annex E. Arithmetic Coding
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var ArithmeticDecoder = (function ArithmeticDecoderClosure() {
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var QeTable = [
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{qe: 0x5601, nmps: 1, nlps: 1, switchFlag: 1},
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{qe: 0x3401, nmps: 2, nlps: 6, switchFlag: 0},
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{qe: 0x1801, nmps: 3, nlps: 9, switchFlag: 0},
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{qe: 0x0AC1, nmps: 4, nlps: 12, switchFlag: 0},
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{qe: 0x0521, nmps: 5, nlps: 29, switchFlag: 0},
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{qe: 0x0221, nmps: 38, nlps: 33, switchFlag: 0},
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{qe: 0x5601, nmps: 7, nlps: 6, switchFlag: 1},
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{qe: 0x5401, nmps: 8, nlps: 14, switchFlag: 0},
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{qe: 0x4801, nmps: 9, nlps: 14, switchFlag: 0},
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{qe: 0x3801, nmps: 10, nlps: 14, switchFlag: 0},
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{qe: 0x3001, nmps: 11, nlps: 17, switchFlag: 0},
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{qe: 0x2401, nmps: 12, nlps: 18, switchFlag: 0},
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{qe: 0x1C01, nmps: 13, nlps: 20, switchFlag: 0},
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{qe: 0x1601, nmps: 29, nlps: 21, switchFlag: 0},
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{qe: 0x5601, nmps: 15, nlps: 14, switchFlag: 1},
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{qe: 0x5401, nmps: 16, nlps: 14, switchFlag: 0},
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{qe: 0x5101, nmps: 17, nlps: 15, switchFlag: 0},
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{qe: 0x4801, nmps: 18, nlps: 16, switchFlag: 0},
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{qe: 0x3801, nmps: 19, nlps: 17, switchFlag: 0},
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{qe: 0x3401, nmps: 20, nlps: 18, switchFlag: 0},
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{qe: 0x3001, nmps: 21, nlps: 19, switchFlag: 0},
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{qe: 0x2801, nmps: 22, nlps: 19, switchFlag: 0},
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{qe: 0x2401, nmps: 23, nlps: 20, switchFlag: 0},
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{qe: 0x2201, nmps: 24, nlps: 21, switchFlag: 0},
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{qe: 0x1C01, nmps: 25, nlps: 22, switchFlag: 0},
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{qe: 0x1801, nmps: 26, nlps: 23, switchFlag: 0},
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{qe: 0x1601, nmps: 27, nlps: 24, switchFlag: 0},
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{qe: 0x1401, nmps: 28, nlps: 25, switchFlag: 0},
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{qe: 0x1201, nmps: 29, nlps: 26, switchFlag: 0},
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{qe: 0x1101, nmps: 30, nlps: 27, switchFlag: 0},
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{qe: 0x0AC1, nmps: 31, nlps: 28, switchFlag: 0},
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{qe: 0x09C1, nmps: 32, nlps: 29, switchFlag: 0},
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{qe: 0x08A1, nmps: 33, nlps: 30, switchFlag: 0},
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{qe: 0x0521, nmps: 34, nlps: 31, switchFlag: 0},
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{qe: 0x0441, nmps: 35, nlps: 32, switchFlag: 0},
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{qe: 0x02A1, nmps: 36, nlps: 33, switchFlag: 0},
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{qe: 0x0221, nmps: 37, nlps: 34, switchFlag: 0},
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{qe: 0x0141, nmps: 38, nlps: 35, switchFlag: 0},
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{qe: 0x0111, nmps: 39, nlps: 36, switchFlag: 0},
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{qe: 0x0085, nmps: 40, nlps: 37, switchFlag: 0},
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{qe: 0x0049, nmps: 41, nlps: 38, switchFlag: 0},
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{qe: 0x0025, nmps: 42, nlps: 39, switchFlag: 0},
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{qe: 0x0015, nmps: 43, nlps: 40, switchFlag: 0},
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{qe: 0x0009, nmps: 44, nlps: 41, switchFlag: 0},
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{qe: 0x0005, nmps: 45, nlps: 42, switchFlag: 0},
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{qe: 0x0001, nmps: 45, nlps: 43, switchFlag: 0},
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{qe: 0x5601, nmps: 46, nlps: 46, switchFlag: 0}
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];
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function ArithmeticDecoder(data, start, end) {
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this.data = data;
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this.bp = start;
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this.dataEnd = end;
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this.chigh = data[start];
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this.clow = 0;
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this.byteIn();
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this.chigh = ((this.chigh << 7) & 0xFFFF) | ((this.clow >> 9) & 0x7F);
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this.clow = (this.clow << 7) & 0xFFFF;
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this.ct -= 7;
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this.a = 0x8000;
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}
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ArithmeticDecoder.prototype = {
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byteIn: function ArithmeticDecoder_byteIn() {
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var data = this.data;
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var bp = this.bp;
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if (data[bp] == 0xFF) {
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var b1 = data[bp + 1];
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if (b1 > 0x8F) {
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this.clow += 0xFF00;
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this.ct = 8;
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} else {
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bp++;
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this.clow += (data[bp] << 9);
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this.ct = 7;
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this.bp = bp;
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}
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} else {
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bp++;
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this.clow += bp < this.dataEnd ? (data[bp] << 8) : 0xFF00;
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this.ct = 8;
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this.bp = bp;
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}
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if (this.clow > 0xFFFF) {
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this.chigh += (this.clow >> 16);
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this.clow &= 0xFFFF;
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}
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},
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readBit: function ArithmeticDecoder_readBit(cx) {
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var qeIcx = QeTable[cx.index].qe;
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this.a -= qeIcx;
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if (this.chigh < qeIcx) {
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var d = this.exchangeLps(cx);
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this.renormD();
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return d;
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} else {
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this.chigh -= qeIcx;
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if ((this.a & 0x8000) == 0) {
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var d = this.exchangeMps(cx);
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this.renormD();
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return d;
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} else {
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return cx.mps;
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}
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}
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},
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renormD: function ArithmeticDecoder_renormD() {
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do {
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if (this.ct == 0)
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this.byteIn();
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this.a <<= 1;
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this.chigh = ((this.chigh << 1) & 0xFFFF) | ((this.clow >> 15) & 1);
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this.clow = (this.clow << 1) & 0xFFFF;
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this.ct--;
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} while ((this.a & 0x8000) == 0);
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},
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exchangeMps: function ArithmeticDecoder_exchangeMps(cx) {
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var d;
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var qeTableIcx = QeTable[cx.index];
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if (this.a < qeTableIcx.qe) {
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d = 1 - cx.mps;
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if (qeTableIcx.switchFlag == 1) {
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cx.mps = 1 - cx.mps;
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}
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cx.index = qeTableIcx.nlps;
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} else {
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d = cx.mps;
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cx.index = qeTableIcx.nmps;
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}
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return d;
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},
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exchangeLps: function ArithmeticDecoder_exchangeLps(cx) {
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var d;
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var qeTableIcx = QeTable[cx.index];
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if (this.a < qeTableIcx.qe) {
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this.a = qeTableIcx.qe;
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d = cx.mps;
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cx.index = qeTableIcx.nmps;
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} else {
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this.a = qeTableIcx.qe;
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d = 1 - cx.mps;
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if (qeTableIcx.switchFlag == 1) {
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cx.mps = 1 - cx.mps;
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}
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cx.index = qeTableIcx.nlps;
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}
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return d;
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}
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};
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return ArithmeticDecoder;
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})();
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// Utility data structures
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function ContextCache() {}
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ContextCache.prototype = {
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getContexts: function(id) {
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if (id in this)
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return this[id];
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return (this[id] = []);
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}
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};
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function DecodingContext(data, start, end) {
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this.data = data;
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this.start = start;
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this.end = end;
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}
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DecodingContext.prototype = {
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get decoder() {
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var decoder = new ArithmeticDecoder(this.data, this.start, this.end);
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return shadow(this, 'decoder', decoder);
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},
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get contextCache() {
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var cache = new ContextCache();
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return shadow(this, 'contextCache', cache);
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}
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};
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// Annex A. Arithmetic Integer Decoding Procedure
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// A.2 Procedure for decoding values
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function decodeInteger(contextCache, procedure, decoder) {
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var contexts = contextCache.getContexts(procedure);
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var prev = 1;
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var state = 1, v = 0, s;
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var toRead = 32, offset = 4436; // defaults for state 7
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while (state) {
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var cx = contexts[prev];
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if (!cx)
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contexts[prev] = cx = {index: 0, mps: 0};
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var bit = decoder.readBit(cx);
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prev = prev < 256 ? (prev << 1) | bit :
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(((prev << 1) | bit) & 511) | 256;
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switch (state) {
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case 1:
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s = !!bit;
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break;
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case 2:
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if (bit) break;
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state = 7;
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toRead = 2;
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offset = 0;
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break;
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case 3:
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if (bit) break;
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state = 7;
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toRead = 4;
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offset = 4;
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break;
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case 4:
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if (bit) break;
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state = 7;
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toRead = 6;
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offset = 20;
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break;
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case 5:
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if (bit) break;
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state = 7;
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toRead = 8;
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offset = 84;
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break;
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case 6:
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if (bit) break;
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state = 7;
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toRead = 12;
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offset = 340;
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break;
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default:
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v = v * 2 + bit;
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if (--toRead == 0)
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state = 0;
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continue;
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}
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state++;
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}
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v += offset;
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return !s ? v : v > 0 ? -v : null;
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}
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// A.3 The IAID decoding procedure
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function decodeIAID(contextCache, decoder, codeLength) {
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var contexts = contextCache.getContexts('IAID');
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var prev = 1;
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for (var i = 0; i < codeLength; i++) {
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var cx = contexts[prev];
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if (!cx)
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contexts[prev] = cx = {index: 0, mps: 0};
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var bit = decoder.readBit(cx);
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prev = (prev * 2) + bit;
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}
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if (codeLength < 31)
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return prev & ((1 << codeLength) - 1);
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else
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return prev - Math.pow(2, codeLength);
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}
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// 7.3 Segment types
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var SegmentTypes = [
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'SymbolDictionary', null, null, null, 'IntermediateTextRegion', null,
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'ImmediateTextRegion', 'ImmediateLosslessTextRegion', null, null, null,
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null, null, null, null, null, 'patternDictionary', null, null, null,
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'IntermediateHalftoneRegion', null, 'ImmediateHalftoneRegion',
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'ImmediateLosslessHalftoneRegion', null, null, null, null, null, null, null,
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null, null, null, null, null, 'IntermediateGenericRegion', null,
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'ImmediateGenericRegion', 'ImmediateLosslessGenericRegion',
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'IntermediateGenericRefinementRegion', null,
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'ImmediateGenericRefinementRegion',
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'ImmediateLosslessGenericRefinementRegion', null, null, null, null,
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'PageInformation', 'EndOfPage', 'EndOfStripe', 'EndOfFile', 'Profiles',
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'Tables', null, null, null, null, null, null, null, null,
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'Extension'
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];
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var CodingTemplates = [
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[{x: -1, y: -2}, {x: 0, y: -2}, {x: 1, y: -2}, {x: -2, y: -1},
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{x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: 2, y: -1},
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{x: -4, y: 0}, {x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}],
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[{x: -1, y: -2}, {x: 0, y: -2}, {x: 1, y: -2}, {x: -2, y: -1},
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{x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: 2, y: -1},
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{x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}],
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[{x: -1, y: -2}, {x: 0, y: -2}, {x: 1, y: -2}, {x: -2, y: -1},
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{x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: -2, y: 0},
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{x: -1, y: 0}],
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[{x: -3, y: -1}, {x: -2, y: -1}, {x: -1, y: -1}, {x: 0, y: -1},
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{x: 1, y: -1}, {x: -4, y: 0}, {x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}]
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];
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var RefinementTemplates = [
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{
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coding: [{x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}],
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reference: [{x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}, {x: 0, y: 0},
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{x: 1, y: 0}, {x: -1, y: 1}, {x: 0, y: 1}, {x: 1, y: 1}]
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},
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{
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coding: [{x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}],
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reference: [{x: 0, y: -1}, {x: -1, y: 0}, {x: 0, y: 0}, {x: 1, y: 0},
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{x: 0, y: 1}, {x: 1, y: 1}]
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}
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];
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var ReusedContexts = [
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0x1CD3, // '00111001101' (template) + '0011' (at),
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0x079A, // '001111001101' + '0',
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0x00E3, // '001110001' + '1',
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0x018B // '011000101' + '1'
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];
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var RefinementReusedContexts = [
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0x0020, // '000' + '0' (coding) + '00010000' + '0' (reference)
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0x0008 // '0000' + '001000'
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];
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function log2(x) {
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var n = 1, i = 0;
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while (x > n) {
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n <<= 1;
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i++;
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}
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return i;
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}
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function readInt32(data, start) {
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return (data[start] << 24) | (data[start + 1] << 16) |
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(data[start + 2] << 8) | data[start + 3];
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}
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function readUint32(data, start) {
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var value = readInt32(data, start);
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return value & 0x80000000 ? (value + 4294967296) : value;
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}
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function readUint16(data, start) {
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return (data[start] << 8) | data[start + 1];
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}
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function readInt8(data, start) {
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return (data[start] << 24) >> 24;
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}
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// 6.2 Generic Region Decoding Procedure
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function decodeBitmap(mmr, width, height, templateIndex, prediction, skip, at,
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decodingContext) {
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if (mmr)
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error('JBIG2 error: MMR encoding is not supported');
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var useskip = !!skip;
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var template = CodingTemplates[templateIndex].concat(at);
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var templateLength = template.length;
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var templateX = new Int32Array(templateLength);
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var templateY = new Int32Array(templateLength);
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for (var k = 0; k < templateLength; k++) {
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templateX[k] = template[k].x;
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templateY[k] = template[k].y;
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}
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var pseudoPixelContext = ReusedContexts[templateIndex];
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var bitmap = [];
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var decoder = decodingContext.decoder;
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var contexts = decodingContext.contextCache.getContexts('GB');
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var ltp = 0;
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for (var i = 0; i < height; i++) {
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if (prediction) {
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var cx = contexts[pseudoPixelContext];
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if (!cx)
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contexts[pseudoPixelContext] = cx = {index: 0, mps: 0};
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var sltp = decoder.readBit(cx);
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ltp ^= sltp;
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}
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if (ltp) {
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bitmap.push(bitmap[bitmap.length - 1]); // duplicate previous row
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continue;
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}
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var row = new Uint8Array(width);
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bitmap.push(row);
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for (var j = 0; j < width; j++) {
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if (useskip && skip[i][j]) {
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row[j] = 0;
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continue;
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}
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var contextLabel = 0;
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for (var k = 0; k < templateLength; k++) {
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var i0 = i + templateY[k], j0 = j + templateX[k];
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if (i0 < 0 || j0 < 0 || j0 >= width)
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contextLabel <<= 1; // out of bound pixel
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else
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contextLabel = (contextLabel << 1) | bitmap[i0][j0];
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}
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var cx = contexts[contextLabel];
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if (!cx)
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contexts[contextLabel] = cx = {index: 0, mps: 0};
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var pixel = decoder.readBit(cx);
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row[j] = pixel;
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}
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}
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return bitmap;
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}
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// 6.3.2 Generic Refinement Region Decoding Procedure
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function decodeRefinement(width, height, templateIndex, referenceBitmap,
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offsetX, offsetY, prediction, at,
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decodingContext) {
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var codingTemplate = RefinementTemplates[templateIndex].coding;
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if (templateIndex == 0)
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codingTemplate = codingTemplate.concat([at[0]]);
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var codingTemplateLength = codingTemplate.length;
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var codingTemplateX = new Int32Array(codingTemplateLength);
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var codingTemplateY = new Int32Array(codingTemplateLength);
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for (var k = 0; k < codingTemplateLength; k++) {
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codingTemplateX[k] = codingTemplate[k].x;
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codingTemplateY[k] = codingTemplate[k].y;
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}
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var referenceTemplate = RefinementTemplates[templateIndex].reference;
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if (templateIndex == 0)
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referenceTemplate = referenceTemplate.concat([at[1]]);
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var referenceTemplateLength = referenceTemplate.length;
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var referenceTemplateX = new Int32Array(referenceTemplateLength);
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var referenceTemplateY = new Int32Array(referenceTemplateLength);
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for (var k = 0; k < referenceTemplateLength; k++) {
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referenceTemplateX[k] = referenceTemplate[k].x;
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referenceTemplateY[k] = referenceTemplate[k].y;
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}
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|
var referenceWidth = referenceBitmap[0].length;
|
|
var referenceHeight = referenceBitmap.length;
|
|
|
|
var pseudoPixelContext = RefinementReusedContexts[templateIndex];
|
|
var bitmap = [];
|
|
|
|
var decoder = decodingContext.decoder;
|
|
var contexts = decodingContext.contextCache.getContexts('GR');
|
|
|
|
var ltp = 0;
|
|
for (var i = 0; i < height; i++) {
|
|
if (prediction) {
|
|
var cx = contexts[pseudoPixelContext];
|
|
if (!cx)
|
|
contexts[pseudoPixelContext] = cx = {index: 0, mps: 0};
|
|
var sltp = decoder.readBit(cx);
|
|
ltp ^= sltp;
|
|
}
|
|
var row = new Uint8Array(width);
|
|
bitmap.push(row);
|
|
for (var j = 0; j < width; j++) {
|
|
if (ltp)
|
|
error('JBIG2 error: prediction is not supported');
|
|
|
|
var contextLabel = 0;
|
|
for (var k = 0; k < codingTemplateLength; k++) {
|
|
var i0 = i + codingTemplateY[k], j0 = j + codingTemplateX[k];
|
|
if (i0 < 0 || j0 < 0 || j0 >= width)
|
|
contextLabel <<= 1; // out of bound pixel
|
|
else
|
|
contextLabel = (contextLabel << 1) | bitmap[i0][j0];
|
|
}
|
|
for (var k = 0; k < referenceTemplateLength; k++) {
|
|
var i0 = i + referenceTemplateY[k] + offsetY;
|
|
var j0 = j + referenceTemplateX[k] + offsetX;
|
|
if (i0 < 0 || i0 >= referenceHeight || j0 < 0 || j0 >= referenceWidth)
|
|
contextLabel <<= 1; // out of bound pixel
|
|
else
|
|
contextLabel = (contextLabel << 1) | referenceBitmap[i0][j0];
|
|
}
|
|
var cx = contexts[contextLabel];
|
|
if (!cx)
|
|
contexts[contextLabel] = cx = {index: 0, mps: 0};
|
|
var pixel = decoder.readBit(cx);
|
|
row[j] = pixel;
|
|
}
|
|
}
|
|
|
|
return bitmap;
|
|
}
|
|
|
|
// 6.5.5 Decoding the symbol dictionary
|
|
function decodeSymbolDictionary(huffman, refinement, symbols,
|
|
numberOfNewSymbols, numberOfExportedSymbols,
|
|
huffmanTables, templateIndex, at,
|
|
refinementTemplateIndex, refinementAt,
|
|
decodingContext) {
|
|
if (huffman)
|
|
error('JBIG2 error: huffman is not supported');
|
|
|
|
var newSymbols = [];
|
|
var currentHeight = 0;
|
|
var symbolCodeLength = log2(symbols.length + numberOfNewSymbols);
|
|
|
|
var decoder = decodingContext.decoder;
|
|
var contextCache = decodingContext.contextCache;
|
|
|
|
while (newSymbols.length < numberOfNewSymbols) {
|
|
var deltaHeight = decodeInteger(contextCache, 'IADH', decoder); // 6.5.6
|
|
currentHeight += deltaHeight;
|
|
var currentWidth = 0;
|
|
var totalWidth = 0;
|
|
while (true) {
|
|
var deltaWidth = decodeInteger(contextCache, 'IADW', decoder); // 6.5.7
|
|
if (deltaWidth == null)
|
|
break; // OOB
|
|
currentWidth += deltaWidth;
|
|
totalWidth += currentWidth;
|
|
var bitmap;
|
|
if (refinement) {
|
|
// 6.5.8.2 Refinement/aggregate-coded symbol bitmap
|
|
var numberOfInstances = decodeInteger(contextCache, 'IAAI', decoder);
|
|
if (numberOfInstances > 1)
|
|
error('JBIG2 error: number of instances > 1 is not supported');
|
|
var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);
|
|
var rdx = decodeInteger(contextCache, 'IARDX', decoder); // 6.4.11.3
|
|
var rdy = decodeInteger(contextCache, 'IARDY', decoder); // 6.4.11.4
|
|
var symbol = symbolId < symbols.length ? symbols[symbolId] :
|
|
newSymbols[symbolId - symbols.length];
|
|
bitmap = decodeRefinement(currentWidth, currentHeight,
|
|
refinementTemplateIndex, symbol, rdx, rdy, false, refinementAt,
|
|
decodingContext);
|
|
} else {
|
|
// 6.5.8.1 Direct-coded symbol bitmap
|
|
bitmap = decodeBitmap(false, currentWidth, currentHeight,
|
|
templateIndex, false, null, at, decodingContext);
|
|
}
|
|
newSymbols.push(bitmap);
|
|
}
|
|
}
|
|
// 6.5.10 Exported symbols
|
|
var exportedSymbols = [];
|
|
var flags = [], currentFlag = false;
|
|
var totalSymbolsLength = symbols.length + numberOfNewSymbols;
|
|
while (flags.length < totalSymbolsLength) {
|
|
var runLength = decodeInteger(contextCache, 'IAEX', decoder);
|
|
while (runLength--)
|
|
flags.push(currentFlag);
|
|
currentFlag = !currentFlag;
|
|
}
|
|
for (var i = 0, ii = symbols.length; i < ii; i++)
|
|
if (flags[i]) exportedSymbols.push(symbols[i]);
|
|
for (var j = 0; j < numberOfNewSymbols; i++, j++)
|
|
if (flags[i]) exportedSymbols.push(newSymbols[j]);
|
|
return exportedSymbols;
|
|
}
|
|
|
|
function decodeTextRegion(huffman, refinement, width, height,
|
|
defaultPixelValue, numberOfSymbolInstances,
|
|
stripSize, inputSymbols, symbolCodeLength,
|
|
transposed, dsOffset, referenceCorner,
|
|
combinationOperator, huffmanTables,
|
|
refinementTemplateIndex, refinementAt,
|
|
decodingContext) {
|
|
if (huffman)
|
|
error('JBIG2 error: huffman is not supported');
|
|
|
|
// Prepare bitmap
|
|
var bitmap = [];
|
|
for (var i = 0; i < height; i++) {
|
|
var row = new Uint8Array(width);
|
|
if (defaultPixelValue) {
|
|
for (var j = 0; j < width; j++)
|
|
row[j] = defaultPixelValue;
|
|
}
|
|
bitmap.push(row);
|
|
}
|
|
|
|
var decoder = decodingContext.decoder;
|
|
var contextCache = decodingContext.contextCache;
|
|
|
|
if (transposed)
|
|
error('JBIG2 error: transposed is not supported');
|
|
|
|
var stripT = -decodeInteger(contextCache, 'IADT', decoder); // 6.4.6
|
|
var firstS = 0;
|
|
var i = 0;
|
|
while (i < numberOfSymbolInstances) {
|
|
var deltaT = decodeInteger(contextCache, 'IADT', decoder); // 6.4.6
|
|
stripT += deltaT;
|
|
|
|
var deltaFirstS = decodeInteger(contextCache, 'IAFS', decoder); // 6.4.7
|
|
firstS += deltaFirstS;
|
|
var currentS = firstS;
|
|
do {
|
|
var currentT = stripSize == 1 ? 0 :
|
|
decodeInteger(contextCache, 'IAIT', decoder); // 6.4.9
|
|
var t = stripSize * stripT + currentT;
|
|
var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);
|
|
var applyRefinement = refinement &&
|
|
decodeInteger(contextCache, 'IARI', decoder);
|
|
var symbolBitmap = inputSymbols[symbolId];
|
|
var symbolWidth = symbolBitmap[0].length;
|
|
var symbolHeight = symbolBitmap.length;
|
|
if (applyRefinement) {
|
|
var rdw = decodeInteger(contextCache, 'IARDW', decoder); // 6.4.11.1
|
|
var rdh = decodeInteger(contextCache, 'IARDH', decoder); // 6.4.11.2
|
|
var rdx = decodeInteger(contextCache, 'IARDX', decoder); // 6.4.11.3
|
|
var rdy = decodeInteger(contextCache, 'IARDY', decoder); // 6.4.11.4
|
|
symbolWidth += rdw;
|
|
symbolHeight += rdh;
|
|
symbolBitmap = decodeRefinement(symbolWidth, symbolHeight,
|
|
refinementTemplateIndex, symbolBitmap, (rdw >> 1) + rdx,
|
|
(rdh >> 1) + rdy, false, refinementAt,
|
|
decodingContext);
|
|
}
|
|
var offsetT = t - ((referenceCorner & 1) ? 0 : symbolHeight);
|
|
var offsetS = currentS - ((referenceCorner & 2) ? symbolWidth : 0);
|
|
for (var t2 = 0; t2 < symbolHeight; t2++) {
|
|
var row = bitmap[offsetT + t2];
|
|
if (!row) continue;
|
|
var symbolRow = symbolBitmap[t2];
|
|
switch (combinationOperator) {
|
|
case 0: // OR
|
|
for (var s2 = 0; s2 < symbolWidth; s2++)
|
|
row[offsetS + s2] |= symbolRow[s2];
|
|
break;
|
|
case 2: // XOR
|
|
for (var s2 = 0; s2 < symbolWidth; s2++)
|
|
row[offsetS + s2] ^= symbolRow[s2];
|
|
break;
|
|
default:
|
|
error('JBIG2 error: operator ' + combinationOperator +
|
|
' is not supported');
|
|
}
|
|
}
|
|
|
|
currentS += symbolWidth - 1;
|
|
i++;
|
|
|
|
var deltaS = decodeInteger(contextCache, 'IADS', decoder); // 6.4.8
|
|
if (deltaS == null)
|
|
break; // OOB
|
|
currentS += deltaS + dsOffset;
|
|
} while (true);
|
|
}
|
|
return bitmap;
|
|
}
|
|
|
|
function readSegmentHeader(data, start) {
|
|
var segmentHeader = {};
|
|
segmentHeader.number = readUint32(data, start);
|
|
var flags = data[start + 4];
|
|
var segmentType = flags & 0x3F;
|
|
if (!SegmentTypes[segmentType])
|
|
error('JBIG2 error: invalid segment type: ' + segmentType);
|
|
segmentHeader.type = segmentType;
|
|
segmentHeader.typeName = SegmentTypes[segmentType];
|
|
segmentHeader.deferredNonRetain = !!(flags & 0x80);
|
|
var pageAssociationFieldSize = !!(flags & 0x40);
|
|
var referredFlags = data[start + 5];
|
|
var referredToCount = (referredFlags >> 5) & 7;
|
|
var retainBits = [referredFlags & 31];
|
|
var position = start + 6;
|
|
if (referredFlags == 7) {
|
|
referredToCount = readInt32(data, position - 1) & 0x1FFFFFFF;
|
|
position += 3;
|
|
var bytes = (referredToCount + 7) >> 3;
|
|
retainBits[0] = data[position++];
|
|
while (--bytes > 0) {
|
|
retainBits.push(data[position++]);
|
|
}
|
|
} else if (referredFlags == 5 || referredFlags == 6)
|
|
error('JBIG2 error: invalid referred-to flags');
|
|
segmentHeader.retainBits = retainBits;
|
|
var referredToSegmentNumberSize = segmentHeader.number <= 256 ? 1 :
|
|
segmentHeader.number <= 65536 ? 2 : 4;
|
|
var referredTo = [];
|
|
for (var i = 0; i < referredToCount; i++) {
|
|
var number = referredToSegmentNumberSize == 1 ? data[position] :
|
|
referredToSegmentNumberSize == 2 ? readUint16(data, position) :
|
|
readUint32(data, position);
|
|
referredTo.push(number);
|
|
position += referredToSegmentNumberSize;
|
|
}
|
|
segmentHeader.referredTo = referredTo;
|
|
if (!pageAssociationFieldSize)
|
|
segmentHeader.pageAssociation = data[position++];
|
|
else {
|
|
segmentHeader.pageAssociation = readUint32(data, position);
|
|
position += 4;
|
|
}
|
|
segmentHeader.length = readUint32(data, position);
|
|
if (segmentHeader.length == 0xFFFFFFFF)
|
|
error('JBIG2 error: unknown segment length is not supported');
|
|
position += 4;
|
|
segmentHeader.headerEnd = position;
|
|
return segmentHeader;
|
|
}
|
|
|
|
function readSegments(header, data, start, end) {
|
|
var segments = [];
|
|
var position = start;
|
|
while (position < end) {
|
|
var segmentHeader = readSegmentHeader(data, position);
|
|
position = segmentHeader.headerEnd;
|
|
var segment = {
|
|
header: segmentHeader,
|
|
data: data
|
|
};
|
|
if (!header.randomAccess) {
|
|
segment.start = position;
|
|
position += segmentHeader.length;
|
|
segment.end = position;
|
|
}
|
|
segments.push(segment);
|
|
if (segmentHeader.type == 51)
|
|
break; // end of file is found
|
|
}
|
|
if (header.randomAccess) {
|
|
for (var i = 0, ii = segments.length; i < ii; i++) {
|
|
segments[i].start = position;
|
|
position += segments[i].header.length;
|
|
segments[i].end = position;
|
|
}
|
|
}
|
|
return segments;
|
|
}
|
|
|
|
// 7.4.1 Region segment information field
|
|
function readRegionSegmentInformation(data, start) {
|
|
return {
|
|
width: readUint32(data, start),
|
|
height: readUint32(data, start + 4),
|
|
x: readUint32(data, start + 8),
|
|
y: readUint32(data, start + 12),
|
|
combinationOperator: data[start + 16] & 7
|
|
};
|
|
}
|
|
var RegionSegmentInformationFieldLength = 17;
|
|
|
|
function processSegment(segment, visitor) {
|
|
var header = segment.header;
|
|
|
|
var data = segment.data, position = segment.start, end = segment.end;
|
|
var args;
|
|
switch (header.type) {
|
|
case 0: // SymbolDictionary
|
|
// 7.4.2 Symbol dictionary segment syntax
|
|
var dictionary = {};
|
|
var dictionaryFlags = readUint16(data, position); // 7.4.2.1.1
|
|
dictionary.huffman = !!(dictionaryFlags & 1);
|
|
dictionary.refinement = !!(dictionaryFlags & 2);
|
|
dictionary.huffmanDHSelector = (dictionaryFlags >> 2) & 3;
|
|
dictionary.huffmanDWSelector = (dictionaryFlags >> 4) & 3;
|
|
dictionary.bitmapSizeSelector = (dictionaryFlags >> 6) & 1;
|
|
dictionary.aggregationInstancesSelector = (dictionaryFlags >> 7) & 1;
|
|
dictionary.bitmapCodingContextUsed = !!(dictionaryFlags & 256);
|
|
dictionary.bitmapCodingContextRetained = !!(dictionaryFlags & 512);
|
|
dictionary.template = (dictionaryFlags >> 10) & 3;
|
|
dictionary.refinementTemplate = (dictionaryFlags >> 12) & 1;
|
|
position += 2;
|
|
if (!dictionary.huffman) {
|
|
var atLength = dictionary.template == 0 ? 4 : 1;
|
|
var at = [];
|
|
for (var i = 0; i < atLength; i++) {
|
|
at.push({
|
|
x: readInt8(data, position),
|
|
y: readInt8(data, position + 1)
|
|
});
|
|
position += 2;
|
|
}
|
|
dictionary.at = at;
|
|
}
|
|
if (dictionary.refinement && !dictionary.refinementTemplate) {
|
|
var at = [];
|
|
for (var i = 0; i < 2; i++) {
|
|
at.push({
|
|
x: readInt8(data, position),
|
|
y: readInt8(data, position + 1)
|
|
});
|
|
position += 2;
|
|
}
|
|
dictionary.refinementAt = at;
|
|
}
|
|
dictionary.numberOfExportedSymbols = readUint32(data, position);
|
|
position += 4;
|
|
dictionary.numberOfNewSymbols = readUint32(data, position);
|
|
position += 4;
|
|
args = [dictionary, header.number, header.referredTo,
|
|
data, position, end];
|
|
break;
|
|
case 6: // ImmediateTextRegion
|
|
case 7: // ImmediateLosslessTextRegion
|
|
var textRegion = {};
|
|
textRegion.info = readRegionSegmentInformation(data, position);
|
|
position += RegionSegmentInformationFieldLength;
|
|
var textRegionSegmentFlags = readUint16(data, position);
|
|
position += 2;
|
|
textRegion.huffman = !!(textRegionSegmentFlags & 1);
|
|
textRegion.refinement = !!(textRegionSegmentFlags & 2);
|
|
textRegion.stripSize = 1 << ((textRegionSegmentFlags >> 2) & 3);
|
|
textRegion.referenceCorner = (textRegionSegmentFlags >> 4) & 3;
|
|
textRegion.transposed = !!(textRegionSegmentFlags & 64);
|
|
textRegion.combinationOperator = (textRegionSegmentFlags >> 7) & 3;
|
|
textRegion.defaultPixelValue = (textRegionSegmentFlags >> 9) & 1;
|
|
textRegion.dsOffset = (textRegionSegmentFlags >> 10) & 31;
|
|
textRegion.refinementTemplate = (textRegionSegmentFlags >> 15) & 1;
|
|
if (textRegion.huffman) {
|
|
var textRegionHuffmanFlags = readUint16(data, position);
|
|
position += 2;
|
|
textRegion.huffmanFS = (textRegionHuffmanFlags) & 3;
|
|
textRegion.huffmanDS = (textRegionHuffmanFlags >> 2) & 3;
|
|
textRegion.huffmanDT = (textRegionHuffmanFlags >> 4) & 3;
|
|
textRegion.huffmanRefinementDW = (textRegionHuffmanFlags >> 6) & 3;
|
|
textRegion.huffmanRefinementDH = (textRegionHuffmanFlags >> 8) & 3;
|
|
textRegion.huffmanRefinementDX = (textRegionHuffmanFlags >> 10) & 3;
|
|
textRegion.huffmanRefinementDY = (textRegionHuffmanFlags >> 12) & 3;
|
|
textRegion.huffmanRefinementSizeSelector =
|
|
!!(textRegionHuffmanFlags & 14);
|
|
}
|
|
if (textRegion.refinement && !textRegion.refinementTemplate) {
|
|
var at = [];
|
|
for (var i = 0; i < 2; i++) {
|
|
at.push({
|
|
x: readInt8(data, position),
|
|
y: readInt8(data, position + 1)
|
|
});
|
|
position += 2;
|
|
}
|
|
textRegion.refinementAt = at;
|
|
}
|
|
textRegion.numberOfSymbolInstances = readUint32(data, position);
|
|
position += 4;
|
|
// TODO 7.4.3.1.7 Symbol ID Huffman table decoding
|
|
if (textRegion.huffman)
|
|
error('JBIG2 error: huffman is not supported');
|
|
args = [textRegion, header.referredTo, data, position, end];
|
|
break;
|
|
case 38: // ImmediateGenericRegion
|
|
case 39: // ImmediateLosslessGenericRegion
|
|
var genericRegion = {};
|
|
genericRegion.info = readRegionSegmentInformation(data, position);
|
|
position += RegionSegmentInformationFieldLength;
|
|
var genericRegionSegmentFlags = data[position++];
|
|
genericRegion.mmr = !!(genericRegionSegmentFlags & 1);
|
|
genericRegion.template = (genericRegionSegmentFlags >> 1) & 3;
|
|
genericRegion.prediction = !!(genericRegionSegmentFlags & 8);
|
|
if (!genericRegion.mmr) {
|
|
var atLength = genericRegion.template == 0 ? 4 : 1;
|
|
var at = [];
|
|
for (var i = 0; i < atLength; i++) {
|
|
at.push({
|
|
x: readInt8(data, position),
|
|
y: readInt8(data, position + 1)
|
|
});
|
|
position += 2;
|
|
}
|
|
genericRegion.at = at;
|
|
}
|
|
args = [genericRegion, data, position, end];
|
|
break;
|
|
case 48: // PageInformation
|
|
var pageInfo = {
|
|
width: readUint32(data, position),
|
|
height: readUint32(data, position + 4),
|
|
resolutionX: readUint32(data, position + 8),
|
|
resolutionY: readUint32(data, position + 12)
|
|
};
|
|
if (pageInfo.height == 0xFFFFFFFF)
|
|
delete pageInfo.height;
|
|
var pageSegmentFlags = data[position + 16];
|
|
var pageStripingInformatiom = readUint16(data, position + 17);
|
|
pageInfo.lossless = !!(pageSegmentFlags & 1);
|
|
pageInfo.refinement = !!(pageSegmentFlags & 2);
|
|
pageInfo.defaultPixelValue = (pageSegmentFlags >> 2) & 1;
|
|
pageInfo.combinationOperator = (pageSegmentFlags >> 3) & 3;
|
|
pageInfo.requiresBuffer = !!(pageSegmentFlags & 32);
|
|
pageInfo.combinationOperatorOverride = !!(pageSegmentFlags & 64);
|
|
args = [pageInfo];
|
|
break;
|
|
case 50: // EndOfStripe
|
|
break;
|
|
case 51: // EndOfFile
|
|
break;
|
|
default:
|
|
error('JBIG2 error: segment type ' + header.typeName + '(' +
|
|
header.type + ') is not implemented');
|
|
}
|
|
var callbackName = 'on' + header.typeName;
|
|
if (callbackName in visitor)
|
|
visitor[callbackName].apply(visitor, args);
|
|
}
|
|
|
|
function processSegments(segments, visitor) {
|
|
for (var i = 0, ii = segments.length; i < ii; i++)
|
|
processSegment(segments[i], visitor);
|
|
}
|
|
|
|
function parseJbig2(data, start, end) {
|
|
var position = start;
|
|
if (data[position] != 0x97 || data[position + 1] != 0x4A ||
|
|
data[position + 2] != 0x42 || data[position + 3] != 0x32 ||
|
|
data[position + 4] != 0x0D || data[position + 5] != 0x0A ||
|
|
data[position + 6] != 0x1A || data[position + 7] != 0x0A)
|
|
error('JBIG2 error: invalid header');
|
|
var header = {};
|
|
position += 8;
|
|
var flags = data[position++];
|
|
header.randomAccess = !(flags & 1);
|
|
if (!(flags & 2)) {
|
|
header.numberOfPages = readUint32(data, position);
|
|
position += 4;
|
|
}
|
|
var segments = readSegments(header, data, position, end);
|
|
error('Not implemented');
|
|
// processSegments(segments, new SimpleSegmentVisitor());
|
|
}
|
|
|
|
function parseJbig2Chunks(chunks) {
|
|
var visitor = new SimpleSegmentVisitor();
|
|
for (var i = 0, ii = chunks.length; i < ii; i++) {
|
|
var chunk = chunks[i];
|
|
var segments = readSegments({}, chunk.data, chunk.start, chunk.end);
|
|
processSegments(segments, visitor);
|
|
}
|
|
return visitor.buffer;
|
|
}
|
|
|
|
function SimpleSegmentVisitor() {}
|
|
|
|
SimpleSegmentVisitor.prototype = {
|
|
onPageInformation: function SimpleSegmentVisitor_onPageInformation(info) {
|
|
this.currentPageInfo = info;
|
|
var rowSize = (info.width + 7) >> 3;
|
|
var buffer = new Uint8Array(rowSize * info.height);
|
|
var fill = info.defaultPixelValue ? 0xFF : 0;
|
|
for (var i = 0, ii = buffer.length; i < ii; i++)
|
|
buffer[i] = fill;
|
|
this.buffer = buffer;
|
|
},
|
|
drawBitmap: function SimpleSegmentVisitor_drawBitmap(regionInfo, bitmap) {
|
|
var pageInfo = this.currentPageInfo;
|
|
var width = regionInfo.width, height = regionInfo.height;
|
|
var rowSize = (pageInfo.width + 7) >> 3;
|
|
var combinationOperator = pageInfo.combinationOperatorOverride ?
|
|
regionInfo.combinationOperator : pageInfo.combinationOperator;
|
|
var buffer = this.buffer;
|
|
for (var i = 0; i < height; i++) {
|
|
var mask = 128 >> (regionInfo.x & 7);
|
|
var offset = (i + regionInfo.y) * rowSize + (regionInfo.x >> 3);
|
|
switch (combinationOperator) {
|
|
case 0: // OR
|
|
for (var j = 0; j < width; j++) {
|
|
buffer[offset] |= bitmap[i][j] ? mask : 0;
|
|
mask >>= 1;
|
|
if (!mask) {
|
|
mask = 128;
|
|
offset++;
|
|
}
|
|
}
|
|
break;
|
|
case 2: // XOR
|
|
for (var j = 0; j < width; j++) {
|
|
buffer[offset] ^= bitmap[i][j] ? mask : 0;
|
|
mask >>= 1;
|
|
if (!mask) {
|
|
mask = 128;
|
|
offset++;
|
|
}
|
|
}
|
|
break;
|
|
default:
|
|
error('JBIG2 error: operator ' + combinationOperator +
|
|
' is not supported');
|
|
}
|
|
}
|
|
},
|
|
onImmediateGenericRegion:
|
|
function SimpleSegmentVisitor_onImmediateGenericRegion(region, data,
|
|
start, end) {
|
|
var regionInfo = region.info;
|
|
var decodingContext = new DecodingContext(data, start, end);
|
|
var bitmap = decodeBitmap(region.mmr, regionInfo.width, regionInfo.height,
|
|
region.template, region.prediction, null,
|
|
region.at, decodingContext);
|
|
this.drawBitmap(regionInfo, bitmap);
|
|
},
|
|
onImmediateLosslessGenericRegion:
|
|
function SimpleSegmentVisitor_onImmediateLosslessGenericRegion() {
|
|
this.onImmediateGenericRegion.apply(this, arguments);
|
|
},
|
|
onSymbolDictionary:
|
|
function SimpleSegmentVisitor_onSymbolDictionary(dictionary,
|
|
currentSegment,
|
|
referredSegments,
|
|
data, start, end) {
|
|
var huffmanTables;
|
|
if (dictionary.huffman)
|
|
error('JBIG2 error: huffman is not supported');
|
|
|
|
// Combines exported symbols from all referred segments
|
|
var symbols = this.symbols;
|
|
if (!symbols)
|
|
this.symbols = symbols = {};
|
|
|
|
var inputSymbols = [];
|
|
for (var i = 0, ii = referredSegments.length; i < ii; i++)
|
|
inputSymbols = inputSymbols.concat(symbols[referredSegments[i]]);
|
|
|
|
var decodingContext = new DecodingContext(data, start, end);
|
|
symbols[currentSegment] = decodeSymbolDictionary(dictionary.huffman,
|
|
dictionary.refinement, inputSymbols, dictionary.numberOfNewSymbols,
|
|
dictionary.numberOfExportedSymbols, huffmanTables,
|
|
dictionary.template, dictionary.at,
|
|
dictionary.refinementTemplate, dictionary.refinementAt,
|
|
decodingContext);
|
|
},
|
|
onImmediateTextRegion:
|
|
function SimpleSegmentVisitor_onImmediateTextRegion(region,
|
|
referredSegments,
|
|
data, start, end) {
|
|
var regionInfo = region.info;
|
|
var huffmanTables;
|
|
|
|
// Combines exported symbols from all referred segments
|
|
var symbols = this.symbols;
|
|
var inputSymbols = [];
|
|
for (var i = 0, ii = referredSegments.length; i < ii; i++)
|
|
inputSymbols = inputSymbols.concat(symbols[referredSegments[i]]);
|
|
var symbolCodeLength = log2(inputSymbols.length);
|
|
|
|
var decodingContext = new DecodingContext(data, start, end);
|
|
var bitmap = decodeTextRegion(region.huffman, region.refinement,
|
|
regionInfo.width, regionInfo.height, region.defaultPixelValue,
|
|
region.numberOfSymbolInstances, region.stripSize, inputSymbols,
|
|
symbolCodeLength, region.transposed, region.dsOffset,
|
|
region.referenceCorner, region.combinationOperator, huffmanTables,
|
|
region.refinementTemplate, region.refinementAt, decodingContext);
|
|
this.drawBitmap(regionInfo, bitmap);
|
|
},
|
|
onImmediateLosslessTextRegion:
|
|
function SimpleSegmentVisitor_onImmediateLosslessTextRegion() {
|
|
this.onImmediateTextRegion.apply(this, arguments);
|
|
}
|
|
};
|
|
|
|
function Jbig2Image() {}
|
|
|
|
Jbig2Image.prototype = {
|
|
parseChunks: function Jbig2Image_parseChunks(chunks) {
|
|
return parseJbig2Chunks(chunks);
|
|
}
|
|
};
|
|
|
|
return Jbig2Image;
|
|
})();
|