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1061 lines
38 KiB
1061 lines
38 KiB
/* -*- 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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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var pseudoPixelContext = ReusedContexts[templateIndex]; |
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var bitmap = []; |
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|
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var decoder = decodingContext.decoder; |
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var contexts = decodingContext.contextCache.getContexts('GB'); |
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|
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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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|
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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; |
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var referenceHeight = referenceBitmap.length; |
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|
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var pseudoPixelContext = RefinementReusedContexts[templateIndex]; |
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var bitmap = []; |
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|
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var decoder = decodingContext.decoder; |
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var contexts = decodingContext.contextCache.getContexts('GR'); |
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|
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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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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 (ltp) |
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error('JBIG2 error: prediction is not supported'); |
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|
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var contextLabel = 0; |
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for (var k = 0; k < codingTemplateLength; k++) { |
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var i0 = i + codingTemplateY[k], j0 = j + codingTemplateX[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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for (var k = 0; k < referenceTemplateLength; k++) { |
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var i0 = i + referenceTemplateY[k] + offsetY; |
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var j0 = j + referenceTemplateX[k] + offsetX; |
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if (i0 < 0 || i0 >= referenceHeight || j0 < 0 || j0 >= referenceWidth) |
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contextLabel <<= 1; // out of bound pixel |
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else |
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contextLabel = (contextLabel << 1) | referenceBitmap[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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|
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return bitmap; |
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} |
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|
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// 6.5.5 Decoding the symbol dictionary |
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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; |
|
})();
|
|
|