Merge pull request #4434 from p01/jbig2Optimizations
Jbig2 optimizations
This commit is contained in:
Yury Delendik
commit
8266225b73
@ -128,41 +128,39 @@ var ArithmeticDecoder = (function ArithmeticDecoderClosure() {
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var cx_index = contexts[pos] >> 1, cx_mps = contexts[pos] & 1;
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var qeTableIcx = QeTable[cx_index];
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var qeIcx = qeTableIcx.qe;
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var nmpsIcx = qeTableIcx.nmps;
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var nlpsIcx = qeTableIcx.nlps;
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var switchIcx = qeTableIcx.switchFlag;
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var d;
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this.a -= qeIcx;
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var a = this.a - qeIcx;
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if (this.chigh < qeIcx) {
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// exchangeLps
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if (this.a < qeIcx) {
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this.a = qeIcx;
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if (a < qeIcx) {
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a = qeIcx;
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d = cx_mps;
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cx_index = nmpsIcx;
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cx_index = qeTableIcx.nmps;
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} else {
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this.a = qeIcx;
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d = 1 - cx_mps;
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if (switchIcx) {
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a = qeIcx;
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d = 1 ^ cx_mps;
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if (qeTableIcx.switchFlag === 1) {
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cx_mps = d;
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}
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cx_index = nlpsIcx;
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cx_index = qeTableIcx.nlps;
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}
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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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if ((a & 0x8000) !== 0) {
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this.a = a;
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return cx_mps;
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}
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// exchangeMps
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if (this.a < qeIcx) {
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d = 1 - cx_mps;
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if (switchIcx) {
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if (a < qeIcx) {
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d = 1 ^ cx_mps;
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if (qeTableIcx.switchFlag === 1) {
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cx_mps = d;
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}
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cx_index = nlpsIcx;
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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 = nmpsIcx;
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cx_index = qeTableIcx.nmps;
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}
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}
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// C.3.3 renormD;
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@ -171,11 +169,12 @@ var ArithmeticDecoder = (function ArithmeticDecoderClosure() {
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this.byteIn();
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}
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this.a <<= 1;
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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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} while ((a & 0x8000) === 0);
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this.a = a;
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contexts[pos] = cx_index << 1 | cx_mps;
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return d;
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@ -105,7 +105,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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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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v = ((v << 1) | bit) >>> 0;
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if (--toRead === 0) {
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state = 0;
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}
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@ -124,12 +124,12 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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var prev = 1;
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for (var i = 0; i < codeLength; i++) {
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var bit = decoder.readBit(contexts, prev);
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prev = (prev * 2) + bit;
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prev = (prev << 1) | 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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}
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return prev - Math.pow(2, codeLength);
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return prev & 0x7FFFFFFF;
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}
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// 7.3 Segment types
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@ -255,26 +255,41 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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changingTemplateEntries.push(k);
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}
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}
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changingTemplateEntries = new Uint8Array(changingTemplateEntries);
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var changingEntriesLength = changingTemplateEntries.length;
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var changingTemplateX = new Int8Array(changingEntriesLength);
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var changingTemplateY = new Int8Array(changingEntriesLength);
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var changingTemplateBit = new Uint16Array(changingEntriesLength);
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for (var c = 0; c < changingEntriesLength; c++) {
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k = changingTemplateEntries[c];
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changingTemplateX[c] = template[k].x;
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changingTemplateY[c] = template[k].y;
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changingTemplateBit[c] = 1 << (templateLength - 1 - k);
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}
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// Get the safe bounding box edges from the width, height, minX, maxX, minY
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var sbb_left = -minX;
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var sbb_top = -minY;
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var sbb_right = width - maxX;
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var pseudoPixelContext = ReusedContexts[templateIndex];
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var row = new Uint8Array(width);
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var bitmap = [];
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var decoder = decodingContext.decoder;
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var contexts = decodingContext.contextCache.getContexts('GB');
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var ltp = 0, c, j, i0, j0, k, contextLabel = 0;
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var ltp = 0, c, j, i0, j0, k, contextLabel = 0, bit, shift;
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for (var i = 0; i < height; i++) {
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if (prediction) {
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var sltp = decoder.readBit(contexts, pseudoPixelContext);
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ltp ^= sltp;
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if (ltp) {
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bitmap.push(row); // duplicate previous row
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continue;
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}
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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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row = new Uint8Array(row);
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bitmap.push(row);
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for (j = 0; j < width; j++) {
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if (useskip && skip[i][j]) {
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@ -283,24 +298,33 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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}
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// Are we in the middle of a scanline, so we can reuse contextLabel
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// bits?
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if (i + minY > 0 && j + minX >= 0 && j + maxX < width) {
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if (j >= sbb_left && j < sbb_right && i >= sbb_top) {
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// If yes, we can just shift the bits that are reusable and only
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// fetch the remaining ones.
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contextLabel = (contextLabel << 1) & reuseMask;
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for (c = 0; c < changingEntriesLength; c++) {
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k = changingTemplateEntries[c];
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i0 = i + templateY[k];
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j0 = j + templateX[k];
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contextLabel |= bitmap[i0][j0] << (templateLength - 1 - k);
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for (k = 0; k < changingEntriesLength; k++) {
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i0 = i + changingTemplateY[k];
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j0 = j + changingTemplateX[k];
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bit = bitmap[i0][j0];
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if (bit) {
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bit = changingTemplateBit[k];
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contextLabel |= bit;
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}
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}
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} else {
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// compute the contextLabel from scratch
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contextLabel = 0;
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for (k = 0; k < templateLength; k++) {
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i0 = i + templateY[k];
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shift = templateLength - 1;
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for (k = 0; k < templateLength; k++, shift--) {
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j0 = j + templateX[k];
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if (i0 >= 0 && j0 >= 0 && j0 < width) {
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contextLabel |= bitmap[i0][j0] << (templateLength - 1 - k);
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if (j0 >= 0 && j0 < width) {
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i0 = i + templateY[k];
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if (i0 >= 0) {
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bit = bitmap[i0][j0];
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if (bit) {
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contextLabel |= bit << shift;
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}
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}
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}
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}
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}
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@ -352,13 +376,13 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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if (prediction) {
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var sltp = decoder.readBit(contexts, pseudoPixelContext);
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ltp ^= sltp;
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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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}
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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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@ -938,34 +962,46 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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var combinationOperator = pageInfo.combinationOperatorOverride ?
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regionInfo.combinationOperator : pageInfo.combinationOperator;
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var buffer = this.buffer;
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for (var i = 0; i < height; i++) {
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var mask = 128 >> (regionInfo.x & 7);
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var offset = (i + regionInfo.y) * rowSize + (regionInfo.x >> 3);
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switch (combinationOperator) {
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case 0: // OR
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var mask0 = 128 >> (regionInfo.x & 7);
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var offset0 = regionInfo.y * rowSize + (regionInfo.x >> 3);
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switch (combinationOperator) {
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case 0: // OR
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for (var i = 0; i < height; i++) {
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var mask = mask0;
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var offset = offset0;
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for (var j = 0; j < width; j++) {
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buffer[offset] |= bitmap[i][j] ? mask : 0;
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if (bitmap[i][j]) {
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buffer[offset] |= mask;
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}
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mask >>= 1;
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if (!mask) {
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mask = 128;
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offset++;
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}
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}
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break;
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case 2: // XOR
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offset0 += rowSize;
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}
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break;
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case 2: // XOR
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for (var i = 0; i < height; i++) {
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var mask = mask0;
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var offset = offset0;
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for (var j = 0; j < width; j++) {
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buffer[offset] ^= bitmap[i][j] ? mask : 0;
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if (bitmap[i][j]) {
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buffer[offset] ^= mask;
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}
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mask >>= 1;
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if (!mask) {
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mask = 128;
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offset++;
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}
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}
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break;
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default:
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error('JBIG2 error: operator ' + combinationOperator +
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' is not supported');
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}
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offset0 += rowSize;
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}
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break;
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default:
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error('JBIG2 error: operator ' + combinationOperator +
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' is not supported');
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}
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},
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onImmediateGenericRegion:
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