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Generic build of PDF.js library.
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pdfjs-dist/src/core/jpx.js

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/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
/* Copyright 2012 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* globals ArithmeticDecoder, error, globalScope, warn */
'use strict';
var JpxImage = (function JpxImageClosure() {
// Table E.1
var SubbandsGainLog2 = {
'LL': 0,
'LH': 1,
'HL': 1,
'HH': 2
};
function JpxImage() {
this.failOnCorruptedImage = false;
}
JpxImage.prototype = {
load: function JpxImage_load(url) {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = 'arraybuffer';
xhr.onload = (function() {
// TODO catch parse error
var data = new Uint8Array(xhr.response || xhr.mozResponseArrayBuffer);
this.parse(data);
if (this.onload) {
this.onload();
}
}).bind(this);
xhr.send(null);
},
parse: function JpxImage_parse(data) {
function readUint(data, offset, bytes) {
var n = 0;
for (var i = 0; i < bytes; i++) {
n = n * 256 + (data[offset + i] & 0xFF);
}
return n;
}
var head = readUint(data, 0, 2);
// No box header, immediate start of codestream (SOC)
if (head === 0xFF4F) {
this.parseCodestream(data, 0, data.length);
return;
}
var position = 0, length = data.length;
while (position < length) {
var headerSize = 8;
var lbox = readUint(data, position, 4);
var tbox = readUint(data, position + 4, 4);
position += headerSize;
if (lbox == 1) {
lbox = readUint(data, position, 8);
position += 8;
headerSize += 8;
}
if (lbox === 0) {
lbox = length - position + headerSize;
}
if (lbox < headerSize) {
error('JPX error: Invalid box field size');
}
var dataLength = lbox - headerSize;
var jumpDataLength = true;
switch (tbox) {
case 0x6A501A1A: // 'jP\032\032'
// TODO
break;
case 0x6A703268: // 'jp2h'
jumpDataLength = false; // parsing child boxes
break;
case 0x636F6C72: // 'colr'
// TODO
break;
case 0x6A703263: // 'jp2c'
this.parseCodestream(data, position, position + dataLength);
break;
}
if (jumpDataLength) {
position += dataLength;
}
}
},
parseImageProperties: function JpxImage_parseImageProperties(stream) {
try {
var newByte = stream.getByte();
while (newByte >= 0) {
var oldByte = newByte;
newByte = stream.getByte();
var code = (oldByte << 8) | newByte;
// Image and tile size (SIZ)
if (code == 0xFF51) {
stream.skip(4);
var Xsiz = stream.getUint32(); // Byte 4
var Ysiz = stream.getUint32(); // Byte 8
var XOsiz = stream.getUint32(); // Byte 12
var YOsiz = stream.getUint32(); // Byte 16
stream.skip(16);
var Csiz = stream.getUint16(); // Byte 36
this.width = Xsiz - XOsiz;
this.height = Ysiz - YOsiz;
this.componentsCount = Csiz;
// Results are always returned as UInt8Arrays
this.bitsPerComponent = 8;
return;
}
}
throw 'No size marker found in JPX stream';
} catch (e) {
if (this.failOnCorruptedImage) {
error('JPX error: ' + e);
} else {
warn('JPX error: ' + e + '. Trying to recover');
}
}
},
parseCodestream: function JpxImage_parseCodestream(data, start, end) {
var context = {};
try {
var position = start;
while (position < end) {
var code = readUint16(data, position);
position += 2;
var length = 0, j, sqcd, spqcds, spqcdSize, scalarExpounded, tile;
switch (code) {
case 0xFF4F: // Start of codestream (SOC)
context.mainHeader = true;
break;
case 0xFFD9: // End of codestream (EOC)
break;
case 0xFF51: // Image and tile size (SIZ)
length = readUint16(data, position);
var siz = {};
siz.Xsiz = readUint32(data, position + 4);
siz.Ysiz = readUint32(data, position + 8);
siz.XOsiz = readUint32(data, position + 12);
siz.YOsiz = readUint32(data, position + 16);
siz.XTsiz = readUint32(data, position + 20);
siz.YTsiz = readUint32(data, position + 24);
siz.XTOsiz = readUint32(data, position + 28);
siz.YTOsiz = readUint32(data, position + 32);
var componentsCount = readUint16(data, position + 36);
siz.Csiz = componentsCount;
var components = [];
j = position + 38;
for (var i = 0; i < componentsCount; i++) {
var component = {
precision: (data[j] & 0x7F) + 1,
isSigned: !!(data[j] & 0x80),
XRsiz: data[j + 1],
YRsiz: data[j + 1]
};
calculateComponentDimensions(component, siz);
components.push(component);
}
context.SIZ = siz;
context.components = components;
calculateTileGrids(context, components);
context.QCC = [];
context.COC = [];
break;
case 0xFF5C: // Quantization default (QCD)
length = readUint16(data, position);
var qcd = {};
j = position + 2;
sqcd = data[j++];
switch (sqcd & 0x1F) {
case 0:
spqcdSize = 8;
scalarExpounded = true;
break;
case 1:
spqcdSize = 16;
scalarExpounded = false;
break;
case 2:
spqcdSize = 16;
scalarExpounded = true;
break;
default:
throw 'Invalid SQcd value ' + sqcd;
}
qcd.noQuantization = (spqcdSize == 8);
qcd.scalarExpounded = scalarExpounded;
qcd.guardBits = sqcd >> 5;
spqcds = [];
while (j < length + position) {
var spqcd = {};
if (spqcdSize == 8) {
spqcd.epsilon = data[j++] >> 3;
spqcd.mu = 0;
} else {
spqcd.epsilon = data[j] >> 3;
spqcd.mu = ((data[j] & 0x7) << 8) | data[j + 1];
j += 2;
}
spqcds.push(spqcd);
}
qcd.SPqcds = spqcds;
if (context.mainHeader) {
context.QCD = qcd;
} else {
context.currentTile.QCD = qcd;
context.currentTile.QCC = [];
}
break;
case 0xFF5D: // Quantization component (QCC)
length = readUint16(data, position);
var qcc = {};
j = position + 2;
var cqcc;
if (context.SIZ.Csiz < 257) {
cqcc = data[j++];
} else {
cqcc = readUint16(data, j);
j += 2;
}
sqcd = data[j++];
switch (sqcd & 0x1F) {
case 0:
spqcdSize = 8;
scalarExpounded = true;
break;
case 1:
spqcdSize = 16;
scalarExpounded = false;
break;
case 2:
spqcdSize = 16;
scalarExpounded = true;
break;
default:
throw 'Invalid SQcd value ' + sqcd;
}
qcc.noQuantization = (spqcdSize == 8);
qcc.scalarExpounded = scalarExpounded;
qcc.guardBits = sqcd >> 5;
spqcds = [];
while (j < (length + position)) {
spqcd = {};
if (spqcdSize == 8) {
spqcd.epsilon = data[j++] >> 3;
spqcd.mu = 0;
} else {
spqcd.epsilon = data[j] >> 3;
spqcd.mu = ((data[j] & 0x7) << 8) | data[j + 1];
j += 2;
}
spqcds.push(spqcd);
}
qcc.SPqcds = spqcds;
if (context.mainHeader) {
context.QCC[cqcc] = qcc;
} else {
context.currentTile.QCC[cqcc] = qcc;
}
break;
case 0xFF52: // Coding style default (COD)
length = readUint16(data, position);
var cod = {};
j = position + 2;
var scod = data[j++];
cod.entropyCoderWithCustomPrecincts = !!(scod & 1);
cod.sopMarkerUsed = !!(scod & 2);
cod.ephMarkerUsed = !!(scod & 4);
var codingStyle = {};
cod.progressionOrder = data[j++];
cod.layersCount = readUint16(data, j);
j += 2;
cod.multipleComponentTransform = data[j++];
cod.decompositionLevelsCount = data[j++];
cod.xcb = (data[j++] & 0xF) + 2;
cod.ycb = (data[j++] & 0xF) + 2;
var blockStyle = data[j++];
cod.selectiveArithmeticCodingBypass = !!(blockStyle & 1);
cod.resetContextProbabilities = !!(blockStyle & 2);
cod.terminationOnEachCodingPass = !!(blockStyle & 4);
cod.verticalyStripe = !!(blockStyle & 8);
cod.predictableTermination = !!(blockStyle & 16);
cod.segmentationSymbolUsed = !!(blockStyle & 32);
cod.reversibleTransformation = data[j++];
if (cod.entropyCoderWithCustomPrecincts) {
var precinctsSizes = [];
while (j < length + position) {
var precinctsSize = data[j++];
precinctsSizes.push({
PPx: precinctsSize & 0xF,
PPy: precinctsSize >> 4
});
}
cod.precinctsSizes = precinctsSizes;
}
if (cod.sopMarkerUsed || cod.ephMarkerUsed ||
cod.selectiveArithmeticCodingBypass ||
cod.resetContextProbabilities ||
cod.terminationOnEachCodingPass ||
cod.verticalyStripe || cod.predictableTermination) {
throw 'Unsupported COD options: ' +
globalScope.JSON.stringify(cod);
}
if (context.mainHeader) {
context.COD = cod;
} else {
context.currentTile.COD = cod;
context.currentTile.COC = [];
}
break;
case 0xFF90: // Start of tile-part (SOT)
length = readUint16(data, position);
tile = {};
tile.index = readUint16(data, position + 2);
tile.length = readUint32(data, position + 4);
tile.dataEnd = tile.length + position - 2;
tile.partIndex = data[position + 8];
tile.partsCount = data[position + 9];
context.mainHeader = false;
if (tile.partIndex === 0) {
// reset component specific settings
tile.COD = context.COD;
tile.COC = context.COC.slice(0); // clone of the global COC
tile.QCD = context.QCD;
tile.QCC = context.QCC.slice(0); // clone of the global COC
}
context.currentTile = tile;
break;
case 0xFF93: // Start of data (SOD)
tile = context.currentTile;
if (tile.partIndex === 0) {
initializeTile(context, tile.index);
buildPackets(context);
}
// moving to the end of the data
length = tile.dataEnd - position;
parseTilePackets(context, data, position, length);
break;
case 0xFF64: // Comment (COM)
length = readUint16(data, position);
// skipping content
break;
case 0xFF53: // Coding style component (COC)
throw 'Codestream code 0xFF53 (COC) is not implemented';
default:
throw 'Unknown codestream code: ' + code.toString(16);
}
position += length;
}
} catch (e) {
if (this.failOnCorruptedImage) {
error('JPX error: ' + e);
} else {
warn('JPX error: ' + e + '. Trying to recover');
}
}
this.tiles = transformComponents(context);
this.width = context.SIZ.Xsiz - context.SIZ.XOsiz;
this.height = context.SIZ.Ysiz - context.SIZ.YOsiz;
this.componentsCount = context.SIZ.Csiz;
}
};
function readUint32(data, offset) {
return (data[offset] << 24) | (data[offset + 1] << 16) |
(data[offset + 2] << 8) | data[offset + 3];
}
function readUint16(data, offset) {
return (data[offset] << 8) | data[offset + 1];
}
function log2(x) {
var n = 1, i = 0;
while (x > n) {
n <<= 1;
i++;
}
return i;
}
function calculateComponentDimensions(component, siz) {
// Section B.2 Component mapping
component.x0 = Math.ceil(siz.XOsiz / component.XRsiz);
component.x1 = Math.ceil(siz.Xsiz / component.XRsiz);
component.y0 = Math.ceil(siz.YOsiz / component.YRsiz);
component.y1 = Math.ceil(siz.Ysiz / component.YRsiz);
component.width = component.x1 - component.x0;
component.height = component.y1 - component.y0;
}
function calculateTileGrids(context, components) {
var siz = context.SIZ;
// Section B.3 Division into tile and tile-components
var tile, tiles = [];
var numXtiles = Math.ceil((siz.Xsiz - siz.XTOsiz) / siz.XTsiz);
var numYtiles = Math.ceil((siz.Ysiz - siz.YTOsiz) / siz.YTsiz);
for (var q = 0; q < numYtiles; q++) {
for (var p = 0; p < numXtiles; p++) {
tile = {};
tile.tx0 = Math.max(siz.XTOsiz + p * siz.XTsiz, siz.XOsiz);
tile.ty0 = Math.max(siz.YTOsiz + q * siz.YTsiz, siz.YOsiz);
tile.tx1 = Math.min(siz.XTOsiz + (p + 1) * siz.XTsiz, siz.Xsiz);
tile.ty1 = Math.min(siz.YTOsiz + (q + 1) * siz.YTsiz, siz.Ysiz);
tile.width = tile.tx1 - tile.tx0;
tile.height = tile.ty1 - tile.ty0;
tile.components = [];
tiles.push(tile);
}
}
context.tiles = tiles;
var componentsCount = siz.Csiz;
for (var i = 0, ii = componentsCount; i < ii; i++) {
var component = components[i];
var tileComponents = [];
for (var j = 0, jj = tiles.length; j < jj; j++) {
var tileComponent = {};
tile = tiles[j];
tileComponent.tcx0 = Math.ceil(tile.tx0 / component.XRsiz);
tileComponent.tcy0 = Math.ceil(tile.ty0 / component.YRsiz);
tileComponent.tcx1 = Math.ceil(tile.tx1 / component.XRsiz);
tileComponent.tcy1 = Math.ceil(tile.ty1 / component.YRsiz);
tileComponent.width = tileComponent.tcx1 - tileComponent.tcx0;
tileComponent.height = tileComponent.tcy1 - tileComponent.tcy0;
tile.components[i] = tileComponent;
}
}
}
function getBlocksDimensions(context, component, r) {
var codOrCoc = component.codingStyleParameters;
var result = {};
if (!codOrCoc.entropyCoderWithCustomPrecincts) {
result.PPx = 15;
result.PPy = 15;
} else {
result.PPx = codOrCoc.precinctsSizes[r].PPx;
result.PPy = codOrCoc.precinctsSizes[r].PPy;
}
// calculate codeblock size as described in section B.7
result.xcb_ = (r > 0 ? Math.min(codOrCoc.xcb, result.PPx - 1) :
Math.min(codOrCoc.xcb, result.PPx));
result.ycb_ = (r > 0 ? Math.min(codOrCoc.ycb, result.PPy - 1) :
Math.min(codOrCoc.ycb, result.PPy));
return result;
}
function buildPrecincts(context, resolution, dimensions) {
// Section B.6 Division resolution to precincts
var precinctWidth = 1 << dimensions.PPx;
var precinctHeight = 1 << dimensions.PPy;
var numprecinctswide = (resolution.trx1 > resolution.trx0 ?
Math.ceil(resolution.trx1 / precinctWidth) -
Math.floor(resolution.trx0 / precinctWidth) : 0);
var numprecinctshigh = (resolution.try1 > resolution.try0 ?
Math.ceil(resolution.try1 / precinctHeight) -
Math.floor(resolution.try0 / precinctHeight) : 0);
var numprecincts = numprecinctswide * numprecinctshigh;
var precinctXOffset = Math.floor(resolution.trx0 / precinctWidth) *
precinctWidth;
var precinctYOffset = Math.floor(resolution.try0 / precinctHeight) *
precinctHeight;
resolution.precinctParameters = {
precinctXOffset: precinctXOffset,
precinctYOffset: precinctYOffset,
precinctWidth: precinctWidth,
precinctHeight: precinctHeight,
numprecinctswide: numprecinctswide,
numprecinctshigh: numprecinctshigh,
numprecincts: numprecincts
};
}
function buildCodeblocks(context, subband, dimensions) {
// Section B.7 Division sub-band into code-blocks
var xcb_ = dimensions.xcb_;
var ycb_ = dimensions.ycb_;
var codeblockWidth = 1 << xcb_;
var codeblockHeight = 1 << ycb_;
var cbx0 = subband.tbx0 >> xcb_;
var cby0 = subband.tby0 >> ycb_;
var cbx1 = (subband.tbx1 + codeblockWidth - 1) >> xcb_;
var cby1 = (subband.tby1 + codeblockHeight - 1) >> ycb_;
var precinctParameters = subband.resolution.precinctParameters;
var codeblocks = [];
var precincts = [];
var i, ii, j, codeblock, precinctNumber;
for (j = cby0; j < cby1; j++) {
for (i = cbx0; i < cbx1; i++) {
codeblock = {
cbx: i,
cby: j,
tbx0: codeblockWidth * i,
tby0: codeblockHeight * j,
tbx1: codeblockWidth * (i + 1),
tby1: codeblockHeight * (j + 1)
};
// calculate precinct number
var pi = Math.floor((codeblock.tbx0 -
precinctParameters.precinctXOffset) /
precinctParameters.precinctWidth);
var pj = Math.floor((codeblock.tby0 -
precinctParameters.precinctYOffset) /
precinctParameters.precinctHeight);
precinctNumber = pj + pi * precinctParameters.numprecinctswide;
codeblock.tbx0_ = Math.max(subband.tbx0, codeblock.tbx0);
codeblock.tby0_ = Math.max(subband.tby0, codeblock.tby0);
codeblock.tbx1_ = Math.min(subband.tbx1, codeblock.tbx1);
codeblock.tby1_ = Math.min(subband.tby1, codeblock.tby1);
codeblock.precinctNumber = precinctNumber;
codeblock.subbandType = subband.type;
var coefficientsLength = (codeblock.tbx1_ - codeblock.tbx0_) *
(codeblock.tby1_ - codeblock.tby0_);
codeblock.Lblock = 3;
codeblocks.push(codeblock);
// building precinct for the sub-band
var precinct = precincts[precinctNumber];
if (precinct !== undefined) {
if (i < precinct.cbxMin) {
precinct.cbxMin = i;
} else if (i > precinct.cbxMax) {
precinct.cbxMax = i;
}
if (j < precinct.cbyMin) {
precinct.cbxMin = j;
} else if (j > precinct.cbyMax) {
precinct.cbyMax = j;
}
} else {
precincts[precinctNumber] = precinct = {
cbxMin: i,
cbyMin: j,
cbxMax: i,
cbyMax: j
};
}
codeblock.precinct = precinct;
}
}
subband.codeblockParameters = {
codeblockWidth: xcb_,
codeblockHeight: ycb_,
numcodeblockwide: cbx1 - cbx0 + 1,
numcodeblockhigh: cby1 - cby1 + 1
};
subband.codeblocks = codeblocks;
subband.precincts = precincts;
}
function createPacket(resolution, precinctNumber, layerNumber) {
var precinctCodeblocks = [];
// Section B.10.8 Order of info in packet
var subbands = resolution.subbands;
// sub-bands already ordered in 'LL', 'HL', 'LH', and 'HH' sequence
for (var i = 0, ii = subbands.length; i < ii; i++) {
var subband = subbands[i];
var codeblocks = subband.codeblocks;
for (var j = 0, jj = codeblocks.length; j < jj; j++) {
var codeblock = codeblocks[j];
if (codeblock.precinctNumber != precinctNumber) {
continue;
}
precinctCodeblocks.push(codeblock);
}
}
return {
layerNumber: layerNumber,
codeblocks: precinctCodeblocks
};
}
function LayerResolutionComponentPositionIterator(context) {
var siz = context.SIZ;
var tileIndex = context.currentTile.index;
var tile = context.tiles[tileIndex];
var layersCount = tile.codingStyleDefaultParameters.layersCount;
var componentsCount = siz.Csiz;
var maxDecompositionLevelsCount = 0;
for (var q = 0; q < componentsCount; q++) {
maxDecompositionLevelsCount = Math.max(maxDecompositionLevelsCount,
tile.components[q].codingStyleParameters.decompositionLevelsCount);
}
var l = 0, r = 0, i = 0, k = 0;
this.nextPacket = function JpxImage_nextPacket() {
// Section B.12.1.1 Layer-resolution-component-position
for (; l < layersCount; l++) {
for (; r <= maxDecompositionLevelsCount; r++) {
for (; i < componentsCount; i++) {
var component = tile.components[i];
if (r > component.codingStyleParameters.decompositionLevelsCount) {
continue;
}
var resolution = component.resolutions[r];
var numprecincts = resolution.precinctParameters.numprecincts;
for (; k < numprecincts;) {
var packet = createPacket(resolution, k, l);
k++;
return packet;
}
k = 0;
}
i = 0;
}
r = 0;
}
throw 'Out of packets';
};
}
function ResolutionLayerComponentPositionIterator(context) {
var siz = context.SIZ;
var tileIndex = context.currentTile.index;
var tile = context.tiles[tileIndex];
var layersCount = tile.codingStyleDefaultParameters.layersCount;
var componentsCount = siz.Csiz;
var maxDecompositionLevelsCount = 0;
for (var q = 0; q < componentsCount; q++) {
maxDecompositionLevelsCount = Math.max(maxDecompositionLevelsCount,
tile.components[q].codingStyleParameters.decompositionLevelsCount);
}
var r = 0, l = 0, i = 0, k = 0;
this.nextPacket = function JpxImage_nextPacket() {
// Section B.12.1.2 Resolution-layer-component-position
for (; r <= maxDecompositionLevelsCount; r++) {
for (; l < layersCount; l++) {
for (; i < componentsCount; i++) {
var component = tile.components[i];
if (r > component.codingStyleParameters.decompositionLevelsCount) {
continue;
}
var resolution = component.resolutions[r];
var numprecincts = resolution.precinctParameters.numprecincts;
for (; k < numprecincts;) {
var packet = createPacket(resolution, k, l);
k++;
return packet;
}
k = 0;
}
i = 0;
}
l = 0;
}
throw 'Out of packets';
};
}
function buildPackets(context) {
var siz = context.SIZ;
var tileIndex = context.currentTile.index;
var tile = context.tiles[tileIndex];
var componentsCount = siz.Csiz;
// Creating resolutions and sub-bands for each component
for (var c = 0; c < componentsCount; c++) {
var component = tile.components[c];
var decompositionLevelsCount =
component.codingStyleParameters.decompositionLevelsCount;
// Section B.5 Resolution levels and sub-bands
var resolutions = [];
var subbands = [];
for (var r = 0; r <= decompositionLevelsCount; r++) {
var blocksDimensions = getBlocksDimensions(context, component, r);
var resolution = {};
var scale = 1 << (decompositionLevelsCount - r);
resolution.trx0 = Math.ceil(component.tcx0 / scale);
resolution.try0 = Math.ceil(component.tcy0 / scale);
resolution.trx1 = Math.ceil(component.tcx1 / scale);
resolution.try1 = Math.ceil(component.tcy1 / scale);
buildPrecincts(context, resolution, blocksDimensions);
resolutions.push(resolution);
var subband;
if (r === 0) {
// one sub-band (LL) with last decomposition
subband = {};
subband.type = 'LL';
subband.tbx0 = Math.ceil(component.tcx0 / scale);
subband.tby0 = Math.ceil(component.tcy0 / scale);
subband.tbx1 = Math.ceil(component.tcx1 / scale);
subband.tby1 = Math.ceil(component.tcy1 / scale);
subband.resolution = resolution;
buildCodeblocks(context, subband, blocksDimensions);
subbands.push(subband);
resolution.subbands = [subband];
} else {
var bscale = 1 << (decompositionLevelsCount - r + 1);
var resolutionSubbands = [];
// three sub-bands (HL, LH and HH) with rest of decompositions
subband = {};
subband.type = 'HL';
subband.tbx0 = Math.ceil(component.tcx0 / bscale - 0.5);
subband.tby0 = Math.ceil(component.tcy0 / bscale);
subband.tbx1 = Math.ceil(component.tcx1 / bscale - 0.5);
subband.tby1 = Math.ceil(component.tcy1 / bscale);
subband.resolution = resolution;
buildCodeblocks(context, subband, blocksDimensions);
subbands.push(subband);
resolutionSubbands.push(subband);
subband = {};
subband.type = 'LH';
subband.tbx0 = Math.ceil(component.tcx0 / bscale);
subband.tby0 = Math.ceil(component.tcy0 / bscale - 0.5);
subband.tbx1 = Math.ceil(component.tcx1 / bscale);
subband.tby1 = Math.ceil(component.tcy1 / bscale - 0.5);
subband.resolution = resolution;
buildCodeblocks(context, subband, blocksDimensions);
subbands.push(subband);
resolutionSubbands.push(subband);
subband = {};
subband.type = 'HH';
subband.tbx0 = Math.ceil(component.tcx0 / bscale - 0.5);
subband.tby0 = Math.ceil(component.tcy0 / bscale - 0.5);
subband.tbx1 = Math.ceil(component.tcx1 / bscale - 0.5);
subband.tby1 = Math.ceil(component.tcy1 / bscale - 0.5);
subband.resolution = resolution;
buildCodeblocks(context, subband, blocksDimensions);
subbands.push(subband);
resolutionSubbands.push(subband);
resolution.subbands = resolutionSubbands;
}
}
component.resolutions = resolutions;
component.subbands = subbands;
}
// Generate the packets sequence
var progressionOrder = tile.codingStyleDefaultParameters.progressionOrder;
var packetsIterator;
switch (progressionOrder) {
case 0:
tile.packetsIterator =
new LayerResolutionComponentPositionIterator(context);
break;
case 1:
tile.packetsIterator =
new ResolutionLayerComponentPositionIterator(context);
break;
default:
throw 'Unsupported progression order ' + progressionOrder;
}
}
function parseTilePackets(context, data, offset, dataLength) {
var position = 0;
var buffer, bufferSize = 0, skipNextBit = false;
function readBits(count) {
while (bufferSize < count) {
var b = data[offset + position];
position++;
if (skipNextBit) {
buffer = (buffer << 7) | b;
bufferSize += 7;
skipNextBit = false;
} else {
buffer = (buffer << 8) | b;
bufferSize += 8;
}
if (b == 0xFF) {
skipNextBit = true;
}
}
bufferSize -= count;
return (buffer >>> bufferSize) & ((1 << count) - 1);
}
function alignToByte() {
bufferSize = 0;
if (skipNextBit) {
position++;
skipNextBit = false;
}
}
function readCodingpasses() {
var value = readBits(1);
if (value === 0) {
return 1;
}
value = (value << 1) | readBits(1);
if (value == 0x02) {
return 2;
}
value = (value << 2) | readBits(2);
if (value <= 0x0E) {
return (value & 0x03) + 3;
}
value = (value << 5) | readBits(5);
if (value <= 0x1FE) {
return (value & 0x1F) + 6;
}
value = (value << 7) | readBits(7);
return (value & 0x7F) + 37;
}
var tileIndex = context.currentTile.index;
var tile = context.tiles[tileIndex];
var packetsIterator = tile.packetsIterator;
while (position < dataLength) {
var packet = packetsIterator.nextPacket();
if (!readBits(1)) {
alignToByte();
continue;
}
var layerNumber = packet.layerNumber;
var queue = [], codeblock;
for (var i = 0, ii = packet.codeblocks.length; i < ii; i++) {
codeblock = packet.codeblocks[i];
var precinct = codeblock.precinct;
var codeblockColumn = codeblock.cbx - precinct.cbxMin;
var codeblockRow = codeblock.cby - precinct.cbyMin;
var codeblockIncluded = false;
var firstTimeInclusion = false;
var valueReady;
if ('included' in codeblock) {
codeblockIncluded = !!readBits(1);
} else {
// reading inclusion tree
precinct = codeblock.precinct;
var inclusionTree, zeroBitPlanesTree;
if ('inclusionTree' in precinct) {
inclusionTree = precinct.inclusionTree;
} else {
// building inclusion and zero bit-planes trees
var width = precinct.cbxMax - precinct.cbxMin + 1;
var height = precinct.cbyMax - precinct.cbyMin + 1;
inclusionTree = new InclusionTree(width, height, layerNumber);
zeroBitPlanesTree = new TagTree(width, height);
precinct.inclusionTree = inclusionTree;
precinct.zeroBitPlanesTree = zeroBitPlanesTree;
}
if (inclusionTree.reset(codeblockColumn, codeblockRow, layerNumber)) {
while (true) {
if (readBits(1)) {
valueReady = !inclusionTree.nextLevel();
if (valueReady) {
codeblock.included = true;
codeblockIncluded = firstTimeInclusion = true;
break;
}
} else {
inclusionTree.incrementValue(layerNumber);
break;
}
}
}
}
if (!codeblockIncluded) {
continue;
}
if (firstTimeInclusion) {
zeroBitPlanesTree = precinct.zeroBitPlanesTree;
zeroBitPlanesTree.reset(codeblockColumn, codeblockRow);
while (true) {
if (readBits(1)) {
valueReady = !zeroBitPlanesTree.nextLevel();
if (valueReady) {
break;
}
} else {
zeroBitPlanesTree.incrementValue();
}
}
codeblock.zeroBitPlanes = zeroBitPlanesTree.value;
}
var codingpasses = readCodingpasses();
while (readBits(1)) {
codeblock.Lblock++;
}
var codingpassesLog2 = log2(codingpasses);
// rounding down log2
var bits = ((codingpasses < (1 << codingpassesLog2)) ?
codingpassesLog2 - 1 : codingpassesLog2) + codeblock.Lblock;
var codedDataLength = readBits(bits);
queue.push({
codeblock: codeblock,
codingpasses: codingpasses,
dataLength: codedDataLength
});
}
alignToByte();
while (queue.length > 0) {
var packetItem = queue.shift();
codeblock = packetItem.codeblock;
if (!('data' in codeblock)) {
codeblock.data = [];
}
codeblock.data.push({
data: data,
start: offset + position,
end: offset + position + packetItem.dataLength,
codingpasses: packetItem.codingpasses
});
position += packetItem.dataLength;
}
}
return position;
}
function copyCoefficients(coefficients, x0, y0, width, height,
delta, mb, codeblocks, reversible,
segmentationSymbolUsed) {
for (var i = 0, ii = codeblocks.length; i < ii; ++i) {
var codeblock = codeblocks[i];
var blockWidth = codeblock.tbx1_ - codeblock.tbx0_;
var blockHeight = codeblock.tby1_ - codeblock.tby0_;
if (blockWidth === 0 || blockHeight === 0) {
continue;
}
if (!('data' in codeblock)) {
continue;
}
var bitModel, currentCodingpassType;
bitModel = new BitModel(blockWidth, blockHeight, codeblock.subbandType,
codeblock.zeroBitPlanes);
currentCodingpassType = 2; // first bit plane starts from cleanup
// collect data
var data = codeblock.data, totalLength = 0, codingpasses = 0;
var q, qq, dataItem;
for (q = 0, qq = data.length; q < qq; q++) {
dataItem = data[q];
totalLength += dataItem.end - dataItem.start;
codingpasses += dataItem.codingpasses;
}
var encodedData = new Uint8Array(totalLength), k = 0;
for (q = 0, qq = data.length; q < qq; q++) {
dataItem = data[q];
var chunk = dataItem.data.subarray(dataItem.start, dataItem.end);
encodedData.set(chunk, k);
k += chunk.length;
}
// decoding the item
var decoder = new ArithmeticDecoder(encodedData, 0, totalLength);
bitModel.setDecoder(decoder);
for (q = 0; q < codingpasses; q++) {
switch (currentCodingpassType) {
case 0:
bitModel.runSignificancePropogationPass();
break;
case 1:
bitModel.runMagnitudeRefinementPass();
break;
case 2:
bitModel.runCleanupPass();
if (segmentationSymbolUsed) {
bitModel.checkSegmentationSymbol();
}
break;
}
currentCodingpassType = (currentCodingpassType + 1) % 3;
}
var offset = (codeblock.tbx0_ - x0) + (codeblock.tby0_ - y0) * width;
var n, nb, correction, position = 0;
var irreversible = !reversible;
var sign = bitModel.coefficentsSign;
var magnitude = bitModel.coefficentsMagnitude;
var bitsDecoded = bitModel.bitsDecoded;
var magnitudeCorrection = reversible ? 0 : 0.5;
for (var j = 0; j < blockHeight; j++) {
for (k = 0; k < blockWidth; k++) {
n = magnitude[position];
if (n !== 0) {
n = (n + magnitudeCorrection) * delta;
if (sign[position] !== 0) {
n = -n;
}
nb = bitsDecoded[position];
if (irreversible || mb > nb) {
coefficients[offset] = n * (1 << (mb - nb));
} else {
coefficients[offset] = n;
}
}
offset++;
position++;
}
offset += width - blockWidth;
}
}
}
function transformTile(context, tile, c) {
var component = tile.components[c];
var codingStyleParameters = component.codingStyleParameters;
var quantizationParameters = component.quantizationParameters;
var decompositionLevelsCount =
codingStyleParameters.decompositionLevelsCount;
var spqcds = quantizationParameters.SPqcds;
var scalarExpounded = quantizationParameters.scalarExpounded;
var guardBits = quantizationParameters.guardBits;
var segmentationSymbolUsed = codingStyleParameters.segmentationSymbolUsed;
var precision = context.components[c].precision;
var reversible = codingStyleParameters.reversibleTransformation;
var transform = (reversible ? new ReversibleTransform() :
new IrreversibleTransform());
var subbandCoefficients = [];
var b = 0;
for (var i = 0; i <= decompositionLevelsCount; i++) {
var resolution = component.resolutions[i];
for (var j = 0, jj = resolution.subbands.length; j < jj; j++) {
var mu, epsilon;
if (!scalarExpounded) {
// formula E-5
mu = spqcds[0].mu;
epsilon = spqcds[0].epsilon + (i > 0 ? 1 - i : 0);
} else {
mu = spqcds[b].mu;
epsilon = spqcds[b].epsilon;
}
var subband = resolution.subbands[j];
var width = subband.tbx1 - subband.tbx0;
var height = subband.tby1 - subband.tby0;
var gainLog2 = SubbandsGainLog2[subband.type];
// calulate quantization coefficient (Section E.1.1.1)
var delta = (reversible ? 1 :
Math.pow(2, precision + gainLog2 - epsilon) * (1 + mu / 2048));
var mb = (guardBits + epsilon - 1);
var coefficients = new Float32Array(width * height);
copyCoefficients(coefficients, subband.tbx0, subband.tby0,
width, height, delta, mb, subband.codeblocks, reversible,
segmentationSymbolUsed);
subbandCoefficients.push({
width: width,
height: height,
items: coefficients
});
b++;
}
}
var result = transform.calculate(subbandCoefficients,
component.tcx0, component.tcy0);
return {
left: component.tcx0,
top: component.tcy0,
width: result.width,
height: result.height,
items: result.items
};
}
function transformComponents(context) {
var siz = context.SIZ;
var components = context.components;
var componentsCount = siz.Csiz;
var resultImages = [];
for (var i = 0, ii = context.tiles.length; i < ii; i++) {
var tile = context.tiles[i];
var result = [];
var c;
for (c = 0; c < componentsCount; c++) {
var image = transformTile(context, tile, c);
result.push(image);
}
// Section G.2.2 Inverse multi component transform
var y0items, y1items, y2items, j, jj, y0, y1, y2;
var component, offset, tileImage, items;
if (tile.codingStyleDefaultParameters.multipleComponentTransform) {
var component0 = tile.components[0];
if (!component0.codingStyleParameters.reversibleTransformation) {
// inverse irreversible multiple component transform
y0items = result[0].items;
y1items = result[1].items;
y2items = result[2].items;
for (j = 0, jj = y0items.length; j < jj; ++j) {
y0 = y0items[j] + 0.5; y1 = y1items[j]; y2 = y2items[j];
y0items[j] = y0 + 1.402 * y2;
y1items[j] = y0 - 0.34413 * y1 - 0.71414 * y2;
y2items[j] = y0 + 1.772 * y1;
}
} else {
// inverse reversible multiple component transform
y0items = result[0].items;
y1items = result[1].items;
y2items = result[2].items;
for (j = 0, jj = y0items.length; j < jj; ++j) {
y0 = y0items[j]; y1 = y1items[j]; y2 = y2items[j];
var i1 = y0 - ((y2 + y1) >> 2);
y1items[j] = i1;
y0items[j] = y2 + i1;
y2items[j] = y1 + i1;
}
}
}
// To simplify things: shift and clamp output to 8 bit unsigned
for (c = 0; c < componentsCount; c++) {
component = components[c];
var shift = component.precision - 8;
tileImage = result[c];
items = tileImage.items;
var data = new Uint8Array(items.length);
var low = -(128 << shift);
var high = 127 << shift;
for (j = 0, jj = items.length; j < jj; j++) {
var val = items[j];
data[j] = val <= low ? 0 : val >= high ? 255 : (val >> shift) + 128;
}
result[c].items = data;
}
resultImages.push(result);
}
return resultImages;
}
function initializeTile(context, tileIndex) {
var siz = context.SIZ;
var componentsCount = siz.Csiz;
var tile = context.tiles[tileIndex];
var resultTiles = [];
for (var c = 0; c < componentsCount; c++) {
var component = tile.components[c];
var qcdOrQcc = (c in context.currentTile.QCC ?
context.currentTile.QCC[c] : context.currentTile.QCD);
component.quantizationParameters = qcdOrQcc;
var codOrCoc = (c in context.currentTile.COC ?
context.currentTile.COC[c] : context.currentTile.COD);
component.codingStyleParameters = codOrCoc;
}
tile.codingStyleDefaultParameters = context.currentTile.COD;
}
// Section B.10.2 Tag trees
var TagTree = (function TagTreeClosure() {
function TagTree(width, height) {
var levelsLength = log2(Math.max(width, height)) + 1;
this.levels = [];
for (var i = 0; i < levelsLength; i++) {
var level = {
width: width,
height: height,
items: []
};
this.levels.push(level);
width = Math.ceil(width / 2);
height = Math.ceil(height / 2);
}
}
TagTree.prototype = {
reset: function TagTree_reset(i, j) {
var currentLevel = 0, value = 0, level;
while (currentLevel < this.levels.length) {
level = this.levels[currentLevel];
var index = i + j * level.width;
if (index in level.items) {
value = level.items[index];
break;
}
level.index = index;
i >>= 1;
j >>= 1;
currentLevel++;
}
currentLevel--;
level = this.levels[currentLevel];
level.items[level.index] = value;
this.currentLevel = currentLevel;
delete this.value;
},
incrementValue: function TagTree_incrementValue() {
var level = this.levels[this.currentLevel];
level.items[level.index]++;
},
nextLevel: function TagTree_nextLevel() {
var currentLevel = this.currentLevel;
var level = this.levels[currentLevel];
var value = level.items[level.index];
currentLevel--;
if (currentLevel < 0) {
this.value = value;
return false;
}
this.currentLevel = currentLevel;
level = this.levels[currentLevel];
level.items[level.index] = value;
return true;
}
};
return TagTree;
})();
var InclusionTree = (function InclusionTreeClosure() {
function InclusionTree(width, height, defaultValue) {
var levelsLength = log2(Math.max(width, height)) + 1;
this.levels = [];
for (var i = 0; i < levelsLength; i++) {
var items = new Uint8Array(width * height);
for (var j = 0, jj = items.length; j < jj; j++) {
items[j] = defaultValue;
}
var level = {
width: width,
height: height,
items: items
};
this.levels.push(level);
width = Math.ceil(width / 2);
height = Math.ceil(height / 2);
}
}
InclusionTree.prototype = {
reset: function InclusionTree_reset(i, j, stopValue) {
var currentLevel = 0;
while (currentLevel < this.levels.length) {
var level = this.levels[currentLevel];
var index = i + j * level.width;
level.index = index;
var value = level.items[index];
if (value == 0xFF) {
break;
}
if (value > stopValue) {
this.currentLevel = currentLevel;
// already know about this one, propagating the value to top levels
this.propagateValues();
return false;
}
i >>= 1;
j >>= 1;
currentLevel++;
}
this.currentLevel = currentLevel - 1;
return true;
},
incrementValue: function InclusionTree_incrementValue(stopValue) {
var level = this.levels[this.currentLevel];
level.items[level.index] = stopValue + 1;
this.propagateValues();
},
propagateValues: function InclusionTree_propagateValues() {
var levelIndex = this.currentLevel;
var level = this.levels[levelIndex];
var currentValue = level.items[level.index];
while (--levelIndex >= 0) {
level = this.levels[levelIndex];
level.items[level.index] = currentValue;
}
},
nextLevel: function InclusionTree_nextLevel() {
var currentLevel = this.currentLevel;
var level = this.levels[currentLevel];
var value = level.items[level.index];
level.items[level.index] = 0xFF;
currentLevel--;
if (currentLevel < 0) {
return false;
}
this.currentLevel = currentLevel;
level = this.levels[currentLevel];
level.items[level.index] = value;
return true;
}
};
return InclusionTree;
})();
// Section D. Coefficient bit modeling
var BitModel = (function BitModelClosure() {
var UNIFORM_CONTEXT = 17;
var RUNLENGTH_CONTEXT = 18;
// Table D-1
// The index is binary presentation: 0dddvvhh, ddd - sum of Di (0..4),
// vv - sum of Vi (0..2), and hh - sum of Hi (0..2)
var LLAndLHContextsLabel = new Uint8Array([
0, 5, 8, 0, 3, 7, 8, 0, 4, 7, 8, 0, 0, 0, 0, 0, 1, 6, 8, 0, 3, 7, 8, 0, 4,
7, 8, 0, 0, 0, 0, 0, 2, 6, 8, 0, 3, 7, 8, 0, 4, 7, 8, 0, 0, 0, 0, 0, 2, 6,
8, 0, 3, 7, 8, 0, 4, 7, 8, 0, 0, 0, 0, 0, 2, 6, 8, 0, 3, 7, 8, 0, 4, 7, 8
]);
var HLContextLabel = new Uint8Array([
0, 3, 4, 0, 5, 7, 7, 0, 8, 8, 8, 0, 0, 0, 0, 0, 1, 3, 4, 0, 6, 7, 7, 0, 8,
8, 8, 0, 0, 0, 0, 0, 2, 3, 4, 0, 6, 7, 7, 0, 8, 8, 8, 0, 0, 0, 0, 0, 2, 3,
4, 0, 6, 7, 7, 0, 8, 8, 8, 0, 0, 0, 0, 0, 2, 3, 4, 0, 6, 7, 7, 0, 8, 8, 8
]);
var HHContextLabel = new Uint8Array([
0, 1, 2, 0, 1, 2, 2, 0, 2, 2, 2, 0, 0, 0, 0, 0, 3, 4, 5, 0, 4, 5, 5, 0, 5,
5, 5, 0, 0, 0, 0, 0, 6, 7, 7, 0, 7, 7, 7, 0, 7, 7, 7, 0, 0, 0, 0, 0, 8, 8,
8, 0, 8, 8, 8, 0, 8, 8, 8, 0, 0, 0, 0, 0, 8, 8, 8, 0, 8, 8, 8, 0, 8, 8, 8
]);
function BitModel(width, height, subband, zeroBitPlanes) {
this.width = width;
this.height = height;
this.contextLabelTable = (subband == 'HH' ? HHContextLabel :
(subband == 'HL' ? HLContextLabel : LLAndLHContextsLabel));
var coefficientCount = width * height;
// coefficients outside the encoding region treated as insignificant
// add border state cells for significanceState
this.neighborsSignificance = new Uint8Array(coefficientCount);
this.coefficentsSign = new Uint8Array(coefficientCount);
this.coefficentsMagnitude = new Uint32Array(coefficientCount);
this.processingFlags = new Uint8Array(coefficientCount);
var bitsDecoded = new Uint8Array(coefficientCount);
if (zeroBitPlanes !== 0) {
for (var i = 0; i < coefficientCount; i++) {
bitsDecoded[i] = zeroBitPlanes;
}
}
this.bitsDecoded = bitsDecoded;
this.reset();
}
BitModel.prototype = {
setDecoder: function BitModel_setDecoder(decoder) {
this.decoder = decoder;
},
reset: function BitModel_reset() {
// We have 17 contexts that are accessed via context labels,
// plus the uniform and runlength context.
this.contexts = new Int8Array(19);
// Contexts are packed into 1 byte:
// highest 7 bits carry the index, lowest bit carries mps
this.contexts[0] = (4 << 1) | 0;
this.contexts[UNIFORM_CONTEXT] = (46 << 1) | 0;
this.contexts[RUNLENGTH_CONTEXT] = (3 << 1) | 0;
},
setNeighborsSignificance:
function BitModel_setNeighborsSignificance(row, column, index) {
var neighborsSignificance = this.neighborsSignificance;
var width = this.width, height = this.height;
var left = (column > 0);
var right = (column + 1 < width);
var i;
if (row > 0) {
i = index - width;
if (left) {
neighborsSignificance[i - 1] += 0x10;
}
if (right) {
neighborsSignificance[i + 1] += 0x10;
}
neighborsSignificance[i] += 0x04;
}
if (row + 1 < height) {
i = index + width;
if (left) {
neighborsSignificance[i - 1] += 0x10;
}
if (right) {
neighborsSignificance[i + 1] += 0x10;
}
neighborsSignificance[i] += 0x04;
}
if (left) {
neighborsSignificance[index - 1] += 0x01;
}
if (right) {
neighborsSignificance[index + 1] += 0x01;
}
neighborsSignificance[index] |= 0x80;
},
runSignificancePropogationPass:
function BitModel_runSignificancePropogationPass() {
var decoder = this.decoder;
var width = this.width, height = this.height;
var coefficentsMagnitude = this.coefficentsMagnitude;
var coefficentsSign = this.coefficentsSign;
var contextLabels = this.contextLabels;
var neighborsSignificance = this.neighborsSignificance;
var processingFlags = this.processingFlags;
var contexts = this.contexts;
var labels = this.contextLabelTable;
var bitsDecoded = this.bitsDecoded;
var processedInverseMask = ~1;
var processedMask = 1;
var firstMagnitudeBitMask = 2;
for (var i0 = 0; i0 < height; i0 += 4) {
for (var j = 0; j < width; j++) {
var index = i0 * width + j;
for (var i1 = 0; i1 < 4; i1++, index += width) {
var i = i0 + i1;
if (i >= height) {
break;
}
// clear processed flag first
processingFlags[index] &= processedInverseMask;
if (coefficentsMagnitude[index] ||
!neighborsSignificance[index]) {
continue;
}
var contextLabel = labels[neighborsSignificance[index]];
var decision = decoder.readBit(contexts, contextLabel);
if (decision) {
var sign = this.decodeSignBit(i, j, index);
coefficentsSign[index] = sign;
coefficentsMagnitude[index] = 1;
this.setNeighborsSignificance(i, j, index);
processingFlags[index] |= firstMagnitudeBitMask;
}
bitsDecoded[index]++;
processingFlags[index] |= processedMask;
}
}
}
},
decodeSignBit: function BitModel_decodeSignBit(row, column, index) {
var width = this.width, height = this.height;
var coefficentsMagnitude = this.coefficentsMagnitude;
var coefficentsSign = this.coefficentsSign;
var contribution, sign0, sign1, significance1;
var contextLabel, decoded;
// calculate horizontal contribution
significance1 = (column > 0 && coefficentsMagnitude[index - 1] !== 0);
if (column + 1 < width && coefficentsMagnitude[index + 1] !== 0) {
sign1 = coefficentsSign[index + 1];
if (significance1) {
sign0 = coefficentsSign[index - 1];
contribution = 1 - sign1 - sign0;
} else {
contribution = 1 - sign1 - sign1;
}
} else if (significance1) {
sign0 = coefficentsSign[index - 1];
contribution = 1 - sign0 - sign0;
} else {
contribution = 0;
}
var horizontalContribution = 3 * contribution;
// calculate vertical contribution and combine with the horizontal
significance1 = (row > 0 && coefficentsMagnitude[index - width] !== 0);
if (row + 1 < height && coefficentsMagnitude[index + width] !== 0) {
sign1 = coefficentsSign[index + width];
if (significance1) {
sign0 = coefficentsSign[index - width];
contribution = 1 - sign1 - sign0 + horizontalContribution;
} else {
contribution = 1 - sign1 - sign1 + horizontalContribution;
}
} else if (significance1) {
sign0 = coefficentsSign[index - width];
contribution = 1 - sign0 - sign0 + horizontalContribution;
} else {
contribution = horizontalContribution;
}
if (contribution >= 0) {
contextLabel = 9 + contribution;
decoded = this.decoder.readBit(this.contexts, contextLabel);
} else {
contextLabel = 9 - contribution;
decoded = this.decoder.readBit(this.contexts, contextLabel) ^ 1;
}
return decoded;
},
runMagnitudeRefinementPass:
function BitModel_runMagnitudeRefinementPass() {
var decoder = this.decoder;
var width = this.width, height = this.height;
var coefficentsMagnitude = this.coefficentsMagnitude;
var neighborsSignificance = this.neighborsSignificance;
var contexts = this.contexts;
var bitsDecoded = this.bitsDecoded;
var processingFlags = this.processingFlags;
var processedMask = 1;
var firstMagnitudeBitMask = 2;
var length = width * height;
var width4 = width * 4;
for (var index0 = 0, indexNext; index0 < length; index0 = indexNext) {
indexNext = Math.min(length, index0 + width4);
for (var j = 0; j < width; j++) {
for (var index = index0 + j; index < indexNext; index += width) {
// significant but not those that have just become
if (!coefficentsMagnitude[index] ||
(processingFlags[index] & processedMask) !== 0) {
continue;
}
var contextLabel = 16;
if ((processingFlags[index] & firstMagnitudeBitMask) !== 0) {
processingFlags[index] ^= firstMagnitudeBitMask;
// first refinement
var significance = neighborsSignificance[index] & 127;
contextLabel = significance === 0 ? 15 : 14;
}
var bit = decoder.readBit(contexts, contextLabel);
coefficentsMagnitude[index] =
(coefficentsMagnitude[index] << 1) | bit;
bitsDecoded[index]++;
processingFlags[index] |= processedMask;
}
}
}
},
runCleanupPass: function BitModel_runCleanupPass() {
var decoder = this.decoder;
var width = this.width, height = this.height;
var neighborsSignificance = this.neighborsSignificance;
var significanceState = this.significanceState;
var coefficentsMagnitude = this.coefficentsMagnitude;
var coefficentsSign = this.coefficentsSign;
var contexts = this.contexts;
var labels = this.contextLabelTable;
var bitsDecoded = this.bitsDecoded;
var processingFlags = this.processingFlags;
var processedMask = 1;
var firstMagnitudeBitMask = 2;
var oneRowDown = width;
var twoRowsDown = width * 2;
var threeRowsDown = width * 3;
for (var i0 = 0; i0 < height; i0 += 4) {
for (var j = 0; j < width; j++) {
var index0 = i0 * width + j;
// using the property: labels[neighborsSignificance[index]] == 0
// when neighborsSignificance[index] == 0
var allEmpty = (i0 + 3 < height &&
processingFlags[index0] === 0 &&
processingFlags[index0 + oneRowDown] === 0 &&
processingFlags[index0 + twoRowsDown] === 0 &&
processingFlags[index0 + threeRowsDown] === 0 &&
neighborsSignificance[index0] === 0 &&
neighborsSignificance[index0 + oneRowDown] === 0 &&
neighborsSignificance[index0 + twoRowsDown] === 0 &&
neighborsSignificance[index0 + threeRowsDown] === 0);
var i1 = 0, index = index0;
var i, sign;
if (allEmpty) {
var hasSignificantCoefficent =
decoder.readBit(contexts, RUNLENGTH_CONTEXT);
if (!hasSignificantCoefficent) {
bitsDecoded[index0]++;
bitsDecoded[index0 + oneRowDown]++;
bitsDecoded[index0 + twoRowsDown]++;
bitsDecoded[index0 + threeRowsDown]++;
continue; // next column
}
i1 = (decoder.readBit(contexts, UNIFORM_CONTEXT) << 1) |
decoder.readBit(contexts, UNIFORM_CONTEXT);
i = i0 + i1;
index += i1 * width;
sign = this.decodeSignBit(i, j, index);
coefficentsSign[index] = sign;
coefficentsMagnitude[index] = 1;
this.setNeighborsSignificance(i, j, index);
processingFlags[index] |= firstMagnitudeBitMask;
index = index0;
for (var i2 = i0; i2 <= i; i2++, index += width) {
bitsDecoded[index]++;
}
i1++;
}
for (; i1 < 4; i1++, index += width) {
i = i0 + i1;
if (i >= height) {
break;
}
if (coefficentsMagnitude[index] ||
(processingFlags[index] & processedMask) !== 0) {
continue;
}
var contextLabel = labels[neighborsSignificance[index]];
var decision = decoder.readBit(contexts, contextLabel);
if (decision == 1) {
sign = this.decodeSignBit(i, j, index);
coefficentsSign[index] = sign;
coefficentsMagnitude[index] = 1;
this.setNeighborsSignificance(i, j, index);
processingFlags[index] |= firstMagnitudeBitMask;
}
bitsDecoded[index]++;
}
}
}
},
checkSegmentationSymbol: function BitModel_checkSegmentationSymbol() {
var decoder = this.decoder;
var contexts = this.contexts;
var symbol = (decoder.readBit(contexts, UNIFORM_CONTEXT) << 3) |
(decoder.readBit(contexts, UNIFORM_CONTEXT) << 2) |
(decoder.readBit(contexts, UNIFORM_CONTEXT) << 1) |
decoder.readBit(contexts, UNIFORM_CONTEXT);
if (symbol != 0xA) {
throw 'Invalid segmentation symbol';
}
}
};
return BitModel;
})();
// Section F, Discrete wavelet transformation
var Transform = (function TransformClosure() {
function Transform() {}
Transform.prototype.calculate =
function transformCalculate(subbands, u0, v0) {
var ll = subbands[0];
for (var i = 1, ii = subbands.length; i < ii; i += 3) {
ll = this.iterate(ll, subbands[i], subbands[i + 1],
subbands[i + 2], u0, v0);
}
return ll;
};
Transform.prototype.extend = function extend(buffer, offset, size) {
// Section F.3.7 extending... using max extension of 4
var i1 = offset - 1, j1 = offset + 1;
var i2 = offset + size - 2, j2 = offset + size;
buffer[i1--] = buffer[j1++];
buffer[j2++] = buffer[i2--];
buffer[i1--] = buffer[j1++];
buffer[j2++] = buffer[i2--];
buffer[i1--] = buffer[j1++];
buffer[j2++] = buffer[i2--];
buffer[i1] = buffer[j1];
buffer[j2] = buffer[i2];
};
Transform.prototype.iterate = function Transform_iterate(ll, hl, lh, hh,
u0, v0) {
var llWidth = ll.width, llHeight = ll.height, llItems = ll.items;
var hlWidth = hl.width, hlHeight = hl.height, hlItems = hl.items;
var lhWidth = lh.width, lhHeight = lh.height, lhItems = lh.items;
var hhWidth = hh.width, hhHeight = hh.height, hhItems = hh.items;
// Section F.3.3 interleave
var width = llWidth + hlWidth;
var height = llHeight + lhHeight;
var items = new Float32Array(width * height);
var i, j, k, l, v, u;
for (i = 0, k = 0; i < llHeight; i++) {
l = i * 2 * width;
for (j = 0; j < llWidth; j++, k++, l += 2) {
items[l] = llItems[k];
}
}
for (i = 0, k = 0; i < hlHeight; i++) {
l = i * 2 * width + 1;
for (j = 0; j < hlWidth; j++, k++, l += 2) {
items[l] = hlItems[k];
}
}
for (i = 0, k = 0; i < lhHeight; i++) {
l = (i * 2 + 1) * width;
for (j = 0; j < lhWidth; j++, k++, l += 2) {
items[l] = lhItems[k];
}
}
for (i = 0, k = 0; i < hhHeight; i++) {
l = (i * 2 + 1) * width + 1;
for (j = 0; j < hhWidth; j++, k++, l += 2) {
items[l] = hhItems[k];
}
}
var bufferPadding = 4;
var rowBuffer = new Float32Array(width + 2 * bufferPadding);
// Section F.3.4 HOR_SR
if (width === 1) {
// if width = 1, when u0 even keep items as is, when odd divide by 2
if ((u0 & 1) !== 0) {
for (v = 0, k = 0; v < height; v++, k += width) {
items[k] *= 0.5;
}
}
} else {
for (v = 0, k = 0; v < height; v++, k += width) {
rowBuffer.set(items.subarray(k, k + width), bufferPadding);
this.extend(rowBuffer, bufferPadding, width);
this.filter(rowBuffer, bufferPadding, width, u0, rowBuffer);
items.set(
rowBuffer.subarray(bufferPadding, bufferPadding + width),
k);
}
}
// Accesses to the items array can take long, because it may not fit into
// CPU cache and has to be fetched from main memory. Since subsequent
// accesses to the items array are not local when reading columns, we
// have a cache miss every time. To reduce cache misses, get up to
// 'numBuffers' items at a time and store them into the individual
// buffers. The colBuffers should be small enough to fit into CPU cache.
var numBuffers = 16;
var colBuffers = [];
for (i = 0; i < numBuffers; i++) {
colBuffers.push(new Float32Array(height + 2 * bufferPadding));
}
var b, currentBuffer = 0;
ll = bufferPadding + height;
// Section F.3.5 VER_SR
if (height === 1) {
// if height = 1, when v0 even keep items as is, when odd divide by 2
if ((v0 & 1) !== 0) {
for (u = 0; u < width; u++) {
items[u] *= 0.5;
}
}
} else {
for (u = 0; u < width; u++) {
// if we ran out of buffers, copy several image columns at once
if (currentBuffer === 0) {
numBuffers = Math.min(width - u, numBuffers);
for (k = u, l = bufferPadding; l < ll; k += width, l++) {
for (b = 0; b < numBuffers; b++) {
colBuffers[b][l] = items[k + b];
}
}
currentBuffer = numBuffers;
}
currentBuffer--;
var buffer = colBuffers[currentBuffer];
this.extend(buffer, bufferPadding, height);
this.filter(buffer, bufferPadding, height, v0, buffer);
// If this is last buffer in this group of buffers, flush all buffers.
if (currentBuffer === 0) {
k = u - numBuffers + 1;
for (l = bufferPadding; l < ll; k += width, l++) {
for (b = 0; b < numBuffers; b++) {
items[k + b] = colBuffers[b][l];
}
}
}
}
}
return {
width: width,
height: height,
items: items
};
};
return Transform;
})();
// Section 3.8.2 Irreversible 9-7 filter
var IrreversibleTransform = (function IrreversibleTransformClosure() {
function IrreversibleTransform() {
Transform.call(this);
}
IrreversibleTransform.prototype = Object.create(Transform.prototype);
IrreversibleTransform.prototype.filter =
function irreversibleTransformFilter(y, offset, length, i0, x) {
var len = length >> 1;
offset = offset | 0;
var alpha = -1.586134342059924;
var beta = -0.052980118572961;
var gamma = 0.882911075530934;
var delta = 0.443506852043971;
var K = 1.230174104914001;
var K_ = 1 / K;
var j, n, nn;
// step 1 is combined with step 3
// step 2
for (j = offset - 3, n = len + 4; n--; j += 2) {
x[j] = K_ * y[j];
}
// step 1 & 3
for (j = offset - 2, n = len + 3; n--; j += 2) {
x[j] = K * y[j] -
delta * (x[j - 1] + x[j + 1]);
}
// step 4
for (j = offset - 1, n = len + 2; n--; j += 2) {
x[j] -= gamma * (x[j - 1] + x[j + 1]);
}
// step 5
for (j = offset, n = len + 1; n--; j += 2) {
x[j] -= beta * (x[j - 1] + x[j + 1]);
}
// step 6
for (j = offset + 1, n = len; n--; j += 2) {
x[j] -= alpha * (x[j - 1] + x[j + 1]);
}
};
return IrreversibleTransform;
})();
// Section 3.8.1 Reversible 5-3 filter
var ReversibleTransform = (function ReversibleTransformClosure() {
function ReversibleTransform() {
Transform.call(this);
}
ReversibleTransform.prototype = Object.create(Transform.prototype);
ReversibleTransform.prototype.filter =
function reversibleTransformFilter(y, offset, length, i0, x) {
var len = length >> 1;
offset = offset | 0;
var j, n;
for (j = offset, n = len + 1; n--; j += 2) {
x[j] = y[j] - ((y[j - 1] + y[j + 1] + 2) >> 2);
}
for (j = offset + 1, n = len; n--; j += 2) {
x[j] = y[j] + ((x[j - 1] + x[j + 1]) >> 1);
}
};
return ReversibleTransform;
})();
return JpxImage;
})();