Convert src/core/jbig2.js to use standard classes
*Please note:* Ignoring whitespace-only changes is probably necessary in order to review this.
This commit is contained in:
Jonas Jenwald
parent
d59c9ab3ab
commit
0addf3a0d4
@ -24,35 +24,33 @@ class Jbig2Error extends BaseException {
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}
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}
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const Jbig2Image = (function Jbig2ImageClosure() {
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// Utility data structures
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function ContextCache() {}
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ContextCache.prototype = {
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class ContextCache {
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getContexts(id) {
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if (id in this) {
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return this[id];
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}
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return (this[id] = new Int8Array(1 << 16));
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},
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};
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}
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}
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function DecodingContext(data, start, end) {
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class DecodingContext {
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constructor(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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const 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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}
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get contextCache() {
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const cache = new ContextCache();
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return shadow(this, "contextCache", cache);
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},
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};
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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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@ -64,8 +62,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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let v = 0;
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for (let i = 0; i < length; i++) {
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const bit = decoder.readBit(contexts, prev);
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prev =
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prev < 256 ? (prev << 1) | bit : (((prev << 1) | bit) & 511) | 256;
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prev = prev < 256 ? (prev << 1) | bit : (((prev << 1) | bit) & 511) | 256;
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v = (v << 1) | bit;
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}
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return v >>> 0;
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@ -555,12 +552,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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for (k = 0; k < referenceTemplateLength; k++) {
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i0 = i + referenceTemplateY[k] - offsetY;
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j0 = j + referenceTemplateX[k] - offsetX;
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if (
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i0 < 0 ||
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i0 >= referenceHeight ||
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j0 < 0 ||
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j0 >= referenceWidth
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) {
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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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@ -626,11 +618,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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let bitmap;
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if (refinement) {
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// 6.5.8.2 Refinement/aggregate-coded symbol bitmap
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const numberOfInstances = decodeInteger(
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contextCache,
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"IAAI",
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decoder
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);
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const numberOfInstances = decodeInteger(contextCache, "IAAI", decoder);
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if (numberOfInstances > 1) {
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bitmap = decodeTextRegion(
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huffman,
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@ -654,11 +642,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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huffmanInput
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);
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} else {
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const symbolId = decodeIAID(
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contextCache,
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decoder,
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symbolCodeLength
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);
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const symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);
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const rdx = decodeInteger(contextCache, "IARDX", decoder); // 6.4.11.3
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const rdy = decodeInteger(contextCache, "IARDY", decoder); // 6.4.11.4
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const symbol =
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@ -1021,9 +1005,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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}
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if (combinationOperator !== 0) {
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throw new Jbig2Error(
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"operator " +
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combinationOperator +
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" is not supported in halftone region"
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`operator "${combinationOperator}" is not supported in halftone region`
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);
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}
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@ -1564,10 +1546,8 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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return { imgData, width, height };
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}
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function SimpleSegmentVisitor() {}
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SimpleSegmentVisitor.prototype = {
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onPageInformation: function SimpleSegmentVisitor_onPageInformation(info) {
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class SimpleSegmentVisitor {
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onPageInformation(info) {
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this.currentPageInfo = info;
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const rowSize = (info.width + 7) >> 3;
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const buffer = new Uint8ClampedArray(rowSize * info.height);
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@ -1579,8 +1559,9 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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}
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}
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this.buffer = buffer;
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},
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drawBitmap: function SimpleSegmentVisitor_drawBitmap(regionInfo, bitmap) {
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}
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drawBitmap(regionInfo, bitmap) {
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const pageInfo = this.currentPageInfo;
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const width = regionInfo.width,
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height = regionInfo.height;
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@ -1632,13 +1613,9 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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`operator ${combinationOperator} is not supported`
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);
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}
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},
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onImmediateGenericRegion: function SimpleSegmentVisitor_onImmediateGenericRegion(
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region,
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data,
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start,
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end
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) {
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}
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onImmediateGenericRegion(region, data, start, end) {
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const regionInfo = region.info;
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const decodingContext = new DecodingContext(data, start, end);
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const bitmap = decodeBitmap(
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@ -1652,11 +1629,13 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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decodingContext
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);
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this.drawBitmap(regionInfo, bitmap);
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},
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onImmediateLosslessGenericRegion: function SimpleSegmentVisitor_onImmediateLosslessGenericRegion() {
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}
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onImmediateLosslessGenericRegion() {
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this.onImmediateGenericRegion.apply(this, arguments);
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},
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onSymbolDictionary: function SimpleSegmentVisitor_onSymbolDictionary(
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}
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onSymbolDictionary(
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dictionary,
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currentSegment,
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referredSegments,
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@ -1705,14 +1684,9 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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decodingContext,
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huffmanInput
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);
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},
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onImmediateTextRegion: function SimpleSegmentVisitor_onImmediateTextRegion(
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region,
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referredSegments,
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data,
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start,
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end
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) {
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}
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onImmediateTextRegion(region, referredSegments, data, start, end) {
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const regionInfo = region.info;
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let huffmanTables, huffmanInput;
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@ -1762,10 +1736,12 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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huffmanInput
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);
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this.drawBitmap(regionInfo, bitmap);
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},
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onImmediateLosslessTextRegion: function SimpleSegmentVisitor_onImmediateLosslessTextRegion() {
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}
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onImmediateLosslessTextRegion() {
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this.onImmediateTextRegion.apply(this, arguments);
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},
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}
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onPatternDictionary(dictionary, currentSegment, data, start, end) {
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let patterns = this.patterns;
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if (!patterns) {
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@ -1780,7 +1756,8 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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dictionary.template,
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decodingContext
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);
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},
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}
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onImmediateHalftoneRegion(region, referredSegments, data, start, end) {
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// HalftoneRegion refers to exactly one PatternDictionary.
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const patterns = this.patterns[referredSegments[0]];
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@ -1804,20 +1781,23 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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decodingContext
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);
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this.drawBitmap(regionInfo, bitmap);
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},
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}
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onImmediateLosslessHalftoneRegion() {
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this.onImmediateHalftoneRegion.apply(this, arguments);
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},
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}
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onTables(currentSegment, data, start, end) {
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let customTables = this.customTables;
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if (!customTables) {
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this.customTables = customTables = {};
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}
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customTables[currentSegment] = decodeTablesSegment(data, start, end);
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},
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};
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}
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}
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function HuffmanLine(lineData) {
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class HuffmanLine {
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constructor(lineData) {
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if (lineData.length === 2) {
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// OOB line.
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this.isOOB = true;
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@ -1837,8 +1817,10 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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this.isLowerRange = lineData[4] === "lower";
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}
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}
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}
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function HuffmanTreeNode(line) {
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class HuffmanTreeNode {
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constructor(line) {
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this.children = [];
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if (line) {
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// Leaf node
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@ -1853,7 +1835,6 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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}
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}
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HuffmanTreeNode.prototype = {
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buildTree(line, shift) {
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const bit = (line.prefixCode >> shift) & 1;
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if (shift <= 0) {
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@ -1867,7 +1848,8 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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}
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node.buildTree(line, shift - 1);
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}
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},
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}
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decodeNode(reader) {
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if (this.isLeaf) {
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if (this.isOOB) {
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@ -1881,10 +1863,11 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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throw new Jbig2Error("invalid Huffman data");
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}
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return node.decodeNode(reader);
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},
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};
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}
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}
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function HuffmanTable(lines, prefixCodesDone) {
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class HuffmanTable {
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constructor(lines, prefixCodesDone) {
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if (!prefixCodesDone) {
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this.assignPrefixCodes(lines);
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}
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@ -1898,10 +1881,10 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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}
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}
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HuffmanTable.prototype = {
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decode(reader) {
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return this.rootNode.decodeNode(reader);
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},
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}
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assignPrefixCodes(lines) {
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// Annex B.3 Assigning the prefix codes.
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const linesLength = lines.length;
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@ -1935,8 +1918,8 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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}
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currentLength++;
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}
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},
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};
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}
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}
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function decodeTablesSegment(data, start, end) {
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// Decodes a Tables segment, i.e., a custom Huffman table.
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@ -1965,9 +1948,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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// Lower range table line
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prefixLength = reader.readBits(prefixSizeBits);
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lines.push(
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new HuffmanLine([lowestValue - 1, prefixLength, 32, 0, "lower"])
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);
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lines.push(new HuffmanLine([lowestValue - 1, prefixLength, 32, 0, "lower"]));
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// Upper range table line
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prefixLength = reader.readBits(prefixSizeBits);
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@ -2248,7 +2229,8 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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return table;
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}
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function Reader(data, start, end) {
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class Reader {
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constructor(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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@ -2257,7 +2239,6 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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this.currentByte = 0;
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}
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Reader.prototype = {
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readBit() {
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if (this.shift < 0) {
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if (this.position >= this.end) {
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@ -2269,7 +2250,7 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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const bit = (this.currentByte >> this.shift) & 1;
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this.shift--;
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return bit;
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},
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}
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readBits(numBits) {
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let result = 0,
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@ -2278,19 +2259,19 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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result |= this.readBit() << i;
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}
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return result;
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},
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}
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byteAlign() {
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this.shift = -1;
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},
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}
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next() {
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if (this.position >= this.end) {
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return -1;
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}
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return this.data[this.position++];
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},
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};
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}
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}
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function getCustomHuffmanTable(index, referredTo, customTables) {
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// Returns a Tables segment that has been earlier decoded.
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@ -2571,23 +2552,17 @@ const Jbig2Image = (function Jbig2ImageClosure() {
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return bitmap;
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}
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// eslint-disable-next-line no-shadow
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function Jbig2Image() {}
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Jbig2Image.prototype = {
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class Jbig2Image {
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parseChunks(chunks) {
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return parseJbig2Chunks(chunks);
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},
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}
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parse(data) {
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const { imgData, width, height } = parseJbig2(data);
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this.width = width;
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this.height = height;
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return imgData;
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},
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};
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return Jbig2Image;
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})();
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}
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}
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export { Jbig2Image };
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