How to use DecodingContext method in wpt

Best JavaScript code snippet using wpt

jbig2.js

Source:jbig2.js

...27      }28      return (this[id] = new Int8Array(1 << 16));29    }30  };31  function DecodingContext(data, start, end) {32    this.data = data;33    this.start = start;34    this.end = end;35  }36  DecodingContext.prototype = {37    get decoder() {38      var decoder = new ArithmeticDecoder(this.data, this.start, this.end);39      return shadow(this, 'decoder', decoder);40    },41    get contextCache() {42      var cache = new ContextCache();43      return shadow(this, 'contextCache', cache);44    }45  };46  // Annex A. Arithmetic Integer Decoding Procedure47  // A.2 Procedure for decoding values48  function decodeInteger(contextCache, procedure, decoder) {49    var contexts = contextCache.getContexts(procedure);50    var prev = 1;51    function readBits(length) {52      var v = 0;53      for (var i = 0; i < length; i++) {54        var bit = decoder.readBit(contexts, prev);55        prev = (prev < 256 ? (prev << 1) | bit :56                (((prev << 1) | bit) & 511) | 256);57        v = (v << 1) | bit;58      }59      return v >>> 0;60    }61    var sign = readBits(1);62    var value = readBits(1) ?63                  (readBits(1) ?64                    (readBits(1) ?65                      (readBits(1) ?66                        (readBits(1) ?67                          (readBits(32) + 4436) :68                        readBits(12) + 340) :69                      readBits(8) + 84) :70                    readBits(6) + 20) :71                  readBits(4) + 4) :72                readBits(2);73    return (sign === 0 ? value : (value > 0 ? -value : null));74  }75  // A.3 The IAID decoding procedure76  function decodeIAID(contextCache, decoder, codeLength) {77    var contexts = contextCache.getContexts('IAID');78    var prev = 1;79    for (var i = 0; i < codeLength; i++) {80      var bit = decoder.readBit(contexts, prev);81      prev = (prev << 1) | bit;82    }83    if (codeLength < 31) {84      return prev & ((1 << codeLength) - 1);85    }86    return prev & 0x7FFFFFFF;87  }88  // 7.3 Segment types89  var SegmentTypes = [90    'SymbolDictionary', null, null, null, 'IntermediateTextRegion', null,91    'ImmediateTextRegion', 'ImmediateLosslessTextRegion', null, null, null,92    null, null, null, null, null, 'patternDictionary', null, null, null,93    'IntermediateHalftoneRegion', null, 'ImmediateHalftoneRegion',94    'ImmediateLosslessHalftoneRegion', null, null, null, null, null, null, null,95    null, null, null, null, null, 'IntermediateGenericRegion', null,96    'ImmediateGenericRegion', 'ImmediateLosslessGenericRegion',97    'IntermediateGenericRefinementRegion', null,98    'ImmediateGenericRefinementRegion',99    'ImmediateLosslessGenericRefinementRegion', null, null, null, null,100    'PageInformation', 'EndOfPage', 'EndOfStripe', 'EndOfFile', 'Profiles',101    'Tables', null, null, null, null, null, null, null, null,102    'Extension'103  ];104  var CodingTemplates = [105    [{x: -1, y: -2}, {x: 0, y: -2}, {x: 1, y: -2}, {x: -2, y: -1},106     {x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: 2, y: -1},107     {x: -4, y: 0}, {x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}],108    [{x: -1, y: -2}, {x: 0, y: -2}, {x: 1, y: -2}, {x: 2, y: -2},109     {x: -2, y: -1}, {x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1},110     {x: 2, y: -1}, {x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}],111    [{x: -1, y: -2}, {x: 0, y: -2}, {x: 1, y: -2}, {x: -2, y: -1},112     {x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: -2, y: 0},113     {x: -1, y: 0}],114    [{x: -3, y: -1}, {x: -2, y: -1}, {x: -1, y: -1}, {x: 0, y: -1},115     {x: 1, y: -1}, {x: -4, y: 0}, {x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}]116  ];117  var RefinementTemplates = [118    {119      coding: [{x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}],120      reference: [{x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}, {x: 0, y: 0},121                  {x: 1, y: 0}, {x: -1, y: 1}, {x: 0, y: 1}, {x: 1, y: 1}]122    },123    {124      coding: [{x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}],125      reference: [{x: 0, y: -1}, {x: -1, y: 0}, {x: 0, y: 0}, {x: 1, y: 0},126                  {x: 0, y: 1}, {x: 1, y: 1}]127    }128  ];129  // See 6.2.5.7 Decoding the bitmap.130  var ReusedContexts = [131    0x9B25, // 10011 0110010 0101132    0x0795, // 0011 110010 101133    0x00E5, // 001 11001 01134    0x0195  // 011001 0101135  ];136  var RefinementReusedContexts = [137    0x0020, // '000' + '0' (coding) + '00010000' + '0' (reference)138    0x0008  // '0000' + '001000'139  ];140  function decodeBitmapTemplate0(width, height, decodingContext) {141    var decoder = decodingContext.decoder;142    var contexts = decodingContext.contextCache.getContexts('GB');143    var contextLabel, i, j, pixel, row, row1, row2, bitmap = [];144    // ...ooooo....145    // ..ooooooo... Context template for current pixel (X)146    // .ooooX...... (concatenate values of 'o'-pixels to get contextLabel)147    var OLD_PIXEL_MASK = 0x7BF7; // 01111 0111111 0111148    for (i = 0; i < height; i++) {149      row = bitmap[i] = new Uint8Array(width);150      row1 = (i < 1) ? row : bitmap[i - 1];151      row2 = (i < 2) ? row : bitmap[i - 2];152      // At the beginning of each row:153      // Fill contextLabel with pixels that are above/right of (X)154      contextLabel = (row2[0] << 13) | (row2[1] << 12) | (row2[2] << 11) |155                     (row1[0] << 7) | (row1[1] << 6) | (row1[2] << 5) |156                     (row1[3] << 4);157      for (j = 0; j < width; j++) {158        row[j] = pixel = decoder.readBit(contexts, contextLabel);159        // At each pixel: Clear contextLabel pixels that are shifted160        // out of the context, then add new ones.161        contextLabel = ((contextLabel & OLD_PIXEL_MASK) << 1) |162                       (j + 3 < width ? row2[j + 3] << 11 : 0) |163                       (j + 4 < width ? row1[j + 4] << 4 : 0) | pixel;164      }165    }166    return bitmap;167  }168  // 6.2 Generic Region Decoding Procedure169  function decodeBitmap(mmr, width, height, templateIndex, prediction, skip, at,170                        decodingContext) {171    if (mmr) {172      error('JBIG2 error: MMR encoding is not supported');173    }174    // Use optimized version for the most common case175    if (templateIndex === 0 && !skip && !prediction && at.length === 4 &&176        at[0].x === 3 && at[0].y === -1 && at[1].x === -3 && at[1].y === -1 &&177        at[2].x === 2 && at[2].y === -2 && at[3].x === -2 && at[3].y === -2) {178      return decodeBitmapTemplate0(width, height, decodingContext);179    }180    var useskip = !!skip;181    var template = CodingTemplates[templateIndex].concat(at);182    // Sorting is non-standard, and it is not required. But sorting increases183    // the number of template bits that can be reused from the previous184    // contextLabel in the main loop.185    template.sort(function (a, b) {186      return (a.y - b.y) || (a.x - b.x);187    });188    var templateLength = template.length;189    var templateX = new Int8Array(templateLength);190    var templateY = new Int8Array(templateLength);191    var changingTemplateEntries = [];192    var reuseMask = 0, minX = 0, maxX = 0, minY = 0;193    var c, k;194    for (k = 0; k < templateLength; k++) {195      templateX[k] = template[k].x;196      templateY[k] = template[k].y;197      minX = Math.min(minX, template[k].x);198      maxX = Math.max(maxX, template[k].x);199      minY = Math.min(minY, template[k].y);200      // Check if the template pixel appears in two consecutive context labels,201      // so it can be reused. Otherwise, we add it to the list of changing202      // template entries.203      if (k < templateLength - 1 &&204          template[k].y === template[k + 1].y &&205          template[k].x === template[k + 1].x - 1) {206        reuseMask |= 1 << (templateLength - 1 - k);207      } else {208        changingTemplateEntries.push(k);209      }210    }211    var changingEntriesLength = changingTemplateEntries.length;212    var changingTemplateX = new Int8Array(changingEntriesLength);213    var changingTemplateY = new Int8Array(changingEntriesLength);214    var changingTemplateBit = new Uint16Array(changingEntriesLength);215    for (c = 0; c < changingEntriesLength; c++) {216      k = changingTemplateEntries[c];217      changingTemplateX[c] = template[k].x;218      changingTemplateY[c] = template[k].y;219      changingTemplateBit[c] = 1 << (templateLength - 1 - k);220    }221    // Get the safe bounding box edges from the width, height, minX, maxX, minY222    var sbb_left = -minX;223    var sbb_top = -minY;224    var sbb_right = width - maxX;225    var pseudoPixelContext = ReusedContexts[templateIndex];226    var row = new Uint8Array(width);227    var bitmap = [];228    var decoder = decodingContext.decoder;229    var contexts = decodingContext.contextCache.getContexts('GB');230    var ltp = 0, j, i0, j0, contextLabel = 0, bit, shift;231    for (var i = 0; i < height; i++) {232      if (prediction) {233        var sltp = decoder.readBit(contexts, pseudoPixelContext);234        ltp ^= sltp;235        if (ltp) {236          bitmap.push(row); // duplicate previous row237          continue;238        }239      }240      row = new Uint8Array(row);241      bitmap.push(row);242      for (j = 0; j < width; j++) {243        if (useskip && skip[i][j]) {244          row[j] = 0;245          continue;246        }247        // Are we in the middle of a scanline, so we can reuse contextLabel248        // bits?249        if (j >= sbb_left && j < sbb_right && i >= sbb_top) {250          // If yes, we can just shift the bits that are reusable and only251          // fetch the remaining ones.252          contextLabel = (contextLabel << 1) & reuseMask;253          for (k = 0; k < changingEntriesLength; k++) {254            i0 = i + changingTemplateY[k];255            j0 = j + changingTemplateX[k];256            bit = bitmap[i0][j0];257            if (bit) {258              bit = changingTemplateBit[k];259              contextLabel |= bit;260            }261          }262        } else {263          // compute the contextLabel from scratch264          contextLabel = 0;265          shift = templateLength - 1;266          for (k = 0; k < templateLength; k++, shift--) {267            j0 = j + templateX[k];268            if (j0 >= 0 && j0 < width) {269              i0 = i + templateY[k];270              if (i0 >= 0) {271                bit = bitmap[i0][j0];272                if (bit) {273                  contextLabel |= bit << shift;274                }275              }276            }277          }278        }279        var pixel = decoder.readBit(contexts, contextLabel);280        row[j] = pixel;281      }282    }283    return bitmap;284  }285  // 6.3.2 Generic Refinement Region Decoding Procedure286  function decodeRefinement(width, height, templateIndex, referenceBitmap,287                            offsetX, offsetY, prediction, at,288                            decodingContext) {289    var codingTemplate = RefinementTemplates[templateIndex].coding;290    if (templateIndex === 0) {291      codingTemplate = codingTemplate.concat([at[0]]);292    }293    var codingTemplateLength = codingTemplate.length;294    var codingTemplateX = new Int32Array(codingTemplateLength);295    var codingTemplateY = new Int32Array(codingTemplateLength);296    var k;297    for (k = 0; k < codingTemplateLength; k++) {298      codingTemplateX[k] = codingTemplate[k].x;299      codingTemplateY[k] = codingTemplate[k].y;300    }301    var referenceTemplate = RefinementTemplates[templateIndex].reference;302    if (templateIndex === 0) {303      referenceTemplate = referenceTemplate.concat([at[1]]);304    }305    var referenceTemplateLength = referenceTemplate.length;306    var referenceTemplateX = new Int32Array(referenceTemplateLength);307    var referenceTemplateY = new Int32Array(referenceTemplateLength);308    for (k = 0; k < referenceTemplateLength; k++) {309      referenceTemplateX[k] = referenceTemplate[k].x;310      referenceTemplateY[k] = referenceTemplate[k].y;311    }312    var referenceWidth = referenceBitmap[0].length;313    var referenceHeight = referenceBitmap.length;314    var pseudoPixelContext = RefinementReusedContexts[templateIndex];315    var bitmap = [];316    var decoder = decodingContext.decoder;317    var contexts = decodingContext.contextCache.getContexts('GR');318    var ltp = 0;319    for (var i = 0; i < height; i++) {320      if (prediction) {321        var sltp = decoder.readBit(contexts, pseudoPixelContext);322        ltp ^= sltp;323        if (ltp) {324          error('JBIG2 error: prediction is not supported');325        }326      }327      var row = new Uint8Array(width);328      bitmap.push(row);329      for (var j = 0; j < width; j++) {330        var i0, j0;331        var contextLabel = 0;332        for (k = 0; k < codingTemplateLength; k++) {333          i0 = i + codingTemplateY[k];334          j0 = j + codingTemplateX[k];335          if (i0 < 0 || j0 < 0 || j0 >= width) {336            contextLabel <<= 1; // out of bound pixel337          } else {338            contextLabel = (contextLabel << 1) | bitmap[i0][j0];339          }340        }341        for (k = 0; k < referenceTemplateLength; k++) {342          i0 = i + referenceTemplateY[k] + offsetY;343          j0 = j + referenceTemplateX[k] + offsetX;344          if (i0 < 0 || i0 >= referenceHeight || j0 < 0 ||345              j0 >= referenceWidth) {346            contextLabel <<= 1; // out of bound pixel347          } else {348            contextLabel = (contextLabel << 1) | referenceBitmap[i0][j0];349          }350        }351        var pixel = decoder.readBit(contexts, contextLabel);352        row[j] = pixel;353      }354    }355    return bitmap;356  }357  // 6.5.5 Decoding the symbol dictionary358  function decodeSymbolDictionary(huffman, refinement, symbols,359                                  numberOfNewSymbols, numberOfExportedSymbols,360                                  huffmanTables, templateIndex, at,361                                  refinementTemplateIndex, refinementAt,362                                  decodingContext) {363    if (huffman) {364      error('JBIG2 error: huffman is not supported');365    }366    var newSymbols = [];367    var currentHeight = 0;368    var symbolCodeLength = log2(symbols.length + numberOfNewSymbols);369    var decoder = decodingContext.decoder;370    var contextCache = decodingContext.contextCache;371    while (newSymbols.length < numberOfNewSymbols) {372      var deltaHeight = decodeInteger(contextCache, 'IADH', decoder); // 6.5.6373      currentHeight += deltaHeight;374      var currentWidth = 0;375      var totalWidth = 0;376      while (true) {377        var deltaWidth = decodeInteger(contextCache, 'IADW', decoder); // 6.5.7378        if (deltaWidth === null) {379          break; // OOB380        }381        currentWidth += deltaWidth;382        totalWidth += currentWidth;383        var bitmap;384        if (refinement) {385          // 6.5.8.2 Refinement/aggregate-coded symbol bitmap386          var numberOfInstances = decodeInteger(contextCache, 'IAAI', decoder);387          if (numberOfInstances > 1) {388            bitmap = decodeTextRegion(huffman, refinement,389                                      currentWidth, currentHeight, 0,390                                      numberOfInstances, 1, //strip size391                                      symbols.concat(newSymbols),392                                      symbolCodeLength,393                                      0, //transposed394                                      0, //ds offset395                                      1, //top left 7.4.3.1.1396                                      0, //OR operator397                                      huffmanTables,398                                      refinementTemplateIndex, refinementAt,399                                      decodingContext);400          } else {401            var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);402            var rdx = decodeInteger(contextCache, 'IARDX', decoder); // 6.4.11.3403            var rdy = decodeInteger(contextCache, 'IARDY', decoder); // 6.4.11.4404            var symbol = (symbolId < symbols.length ? symbols[symbolId] :405                          newSymbols[symbolId - symbols.length]);406            bitmap = decodeRefinement(currentWidth, currentHeight,407            refinementTemplateIndex, symbol, rdx, rdy, false, refinementAt,408            decodingContext);409          }410        } else {411          // 6.5.8.1 Direct-coded symbol bitmap412          bitmap = decodeBitmap(false, currentWidth, currentHeight,413            templateIndex, false, null, at, decodingContext);414        }415        newSymbols.push(bitmap);416      }417    }418    // 6.5.10 Exported symbols419    var exportedSymbols = [];420    var flags = [], currentFlag = false;421    var totalSymbolsLength = symbols.length + numberOfNewSymbols;422    while (flags.length < totalSymbolsLength) {423      var runLength = decodeInteger(contextCache, 'IAEX', decoder);424      while (runLength--) {425        flags.push(currentFlag);426      }427      currentFlag = !currentFlag;428    }429    for (var i = 0, ii = symbols.length; i < ii; i++) {430      if (flags[i]) {431        exportedSymbols.push(symbols[i]);432      }433    }434    for (var j = 0; j < numberOfNewSymbols; i++, j++) {435      if (flags[i]) {436        exportedSymbols.push(newSymbols[j]);437      }438    }439    return exportedSymbols;440  }441  function decodeTextRegion(huffman, refinement, width, height,442                            defaultPixelValue, numberOfSymbolInstances,443                            stripSize, inputSymbols, symbolCodeLength,444                            transposed, dsOffset, referenceCorner,445                            combinationOperator, huffmanTables,446                            refinementTemplateIndex, refinementAt,447                            decodingContext) {448    if (huffman) {449      error('JBIG2 error: huffman is not supported');450    }451    // Prepare bitmap452    var bitmap = [];453    var i, row;454    for (i = 0; i < height; i++) {455      row = new Uint8Array(width);456      if (defaultPixelValue) {457        for (var j = 0; j < width; j++) {458          row[j] = defaultPixelValue;459        }460      }461      bitmap.push(row);462    }463    var decoder = decodingContext.decoder;464    var contextCache = decodingContext.contextCache;465    var stripT = -decodeInteger(contextCache, 'IADT', decoder); // 6.4.6466    var firstS = 0;467    i = 0;468    while (i < numberOfSymbolInstances) {469      var deltaT = decodeInteger(contextCache, 'IADT', decoder); // 6.4.6470      stripT += deltaT;471      var deltaFirstS = decodeInteger(contextCache, 'IAFS', decoder); // 6.4.7472      firstS += deltaFirstS;473      var currentS = firstS;474      do {475        var currentT = (stripSize === 1 ? 0 :476                        decodeInteger(contextCache, 'IAIT', decoder)); // 6.4.9477        var t = stripSize * stripT + currentT;478        var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);479        var applyRefinement = (refinement &&480                               decodeInteger(contextCache, 'IARI', decoder));481        var symbolBitmap = inputSymbols[symbolId];482        var symbolWidth = symbolBitmap[0].length;483        var symbolHeight = symbolBitmap.length;484        if (applyRefinement) {485          var rdw = decodeInteger(contextCache, 'IARDW', decoder); // 6.4.11.1486          var rdh = decodeInteger(contextCache, 'IARDH', decoder); // 6.4.11.2487          var rdx = decodeInteger(contextCache, 'IARDX', decoder); // 6.4.11.3488          var rdy = decodeInteger(contextCache, 'IARDY', decoder); // 6.4.11.4489          symbolWidth += rdw;490          symbolHeight += rdh;491          symbolBitmap = decodeRefinement(symbolWidth, symbolHeight,492            refinementTemplateIndex, symbolBitmap, (rdw >> 1) + rdx,493            (rdh >> 1) + rdy, false, refinementAt,494            decodingContext);495        }496        var offsetT = t - ((referenceCorner & 1) ? 0 : symbolHeight);497        var offsetS = currentS - ((referenceCorner & 2) ? symbolWidth : 0);498        var s2, t2, symbolRow;499        if (transposed) {500          // Place Symbol Bitmap from T1,S1501          for (s2 = 0; s2 < symbolHeight; s2++) {502            row = bitmap[offsetS + s2];503            if (!row) {504              continue;505            }506            symbolRow = symbolBitmap[s2];507            // To ignore Parts of Symbol bitmap which goes508            // outside bitmap region509            var maxWidth = Math.min(width - offsetT, symbolWidth);510            switch (combinationOperator) {511              case 0: // OR512                for (t2 = 0; t2 < maxWidth; t2++) {513                  row[offsetT + t2] |= symbolRow[t2];514                }515                break;516              case 2: // XOR517                for (t2 = 0; t2 < maxWidth; t2++) {518                  row[offsetT + t2] ^= symbolRow[t2];519                }520                break;521              default:522                error('JBIG2 error: operator ' + combinationOperator +523                      ' is not supported');524            }525          }526          currentS += symbolHeight - 1;527        } else {528          for (t2 = 0; t2 < symbolHeight; t2++) {529            row = bitmap[offsetT + t2];530            if (!row) {531              continue;532            }533            symbolRow = symbolBitmap[t2];534            switch (combinationOperator) {535              case 0: // OR536                for (s2 = 0; s2 < symbolWidth; s2++) {537                  row[offsetS + s2] |= symbolRow[s2];538                }539                break;540              case 2: // XOR541                for (s2 = 0; s2 < symbolWidth; s2++) {542                  row[offsetS + s2] ^= symbolRow[s2];543                }544                break;545              default:546                error('JBIG2 error: operator ' + combinationOperator +547                      ' is not supported');548            }549          }550          currentS += symbolWidth - 1;551        }552        i++;553        var deltaS = decodeInteger(contextCache, 'IADS', decoder); // 6.4.8554        if (deltaS === null) {555          break; // OOB556        }557        currentS += deltaS + dsOffset;558      } while (true);559    }560    return bitmap;561  }562  function readSegmentHeader(data, start) {563    var segmentHeader = {};564    segmentHeader.number = readUint32(data, start);565    var flags = data[start + 4];566    var segmentType = flags & 0x3F;567    if (!SegmentTypes[segmentType]) {568      error('JBIG2 error: invalid segment type: ' + segmentType);569    }570    segmentHeader.type = segmentType;571    segmentHeader.typeName = SegmentTypes[segmentType];572    segmentHeader.deferredNonRetain = !!(flags & 0x80);573    var pageAssociationFieldSize = !!(flags & 0x40);574    var referredFlags = data[start + 5];575    var referredToCount = (referredFlags >> 5) & 7;576    var retainBits = [referredFlags & 31];577    var position = start + 6;578    if (referredFlags === 7) {579      referredToCount = readUint32(data, position - 1) & 0x1FFFFFFF;580      position += 3;581      var bytes = (referredToCount + 7) >> 3;582      retainBits[0] = data[position++];583      while (--bytes > 0) {584        retainBits.push(data[position++]);585      }586    } else if (referredFlags === 5 || referredFlags === 6) {587      error('JBIG2 error: invalid referred-to flags');588    }589    segmentHeader.retainBits = retainBits;590    var referredToSegmentNumberSize = (segmentHeader.number <= 256 ? 1 :591      (segmentHeader.number <= 65536 ? 2 : 4));592    var referredTo = [];593    var i, ii;594    for (i = 0; i < referredToCount; i++) {595      var number = (referredToSegmentNumberSize === 1 ? data[position] :596        (referredToSegmentNumberSize === 2 ? readUint16(data, position) :597        readUint32(data, position)));598      referredTo.push(number);599      position += referredToSegmentNumberSize;600    }601    segmentHeader.referredTo = referredTo;602    if (!pageAssociationFieldSize) {603      segmentHeader.pageAssociation = data[position++];604    } else {605      segmentHeader.pageAssociation = readUint32(data, position);606      position += 4;607    }608    segmentHeader.length = readUint32(data, position);609    position += 4;610    if (segmentHeader.length === 0xFFFFFFFF) {611      // 7.2.7 Segment data length, unknown segment length612      if (segmentType === 38) { // ImmediateGenericRegion613        var genericRegionInfo = readRegionSegmentInformation(data, position);614        var genericRegionSegmentFlags = data[position +615          RegionSegmentInformationFieldLength];616        var genericRegionMmr = !!(genericRegionSegmentFlags & 1);617        // searching for the segment end618        var searchPatternLength = 6;619        var searchPattern = new Uint8Array(searchPatternLength);620        if (!genericRegionMmr) {621          searchPattern[0] = 0xFF;622          searchPattern[1] = 0xAC;623        }624        searchPattern[2] = (genericRegionInfo.height >>> 24) & 0xFF;625        searchPattern[3] = (genericRegionInfo.height >> 16) & 0xFF;626        searchPattern[4] = (genericRegionInfo.height >> 8) & 0xFF;627        searchPattern[5] = genericRegionInfo.height & 0xFF;628        for (i = position, ii = data.length; i < ii; i++) {629          var j = 0;630          while (j < searchPatternLength && searchPattern[j] === data[i + j]) {631            j++;632          }633          if (j === searchPatternLength) {634            segmentHeader.length = i + searchPatternLength;635            break;636          }637        }638        if (segmentHeader.length === 0xFFFFFFFF) {639          error('JBIG2 error: segment end was not found');640        }641      } else {642        error('JBIG2 error: invalid unknown segment length');643      }644    }645    segmentHeader.headerEnd = position;646    return segmentHeader;647  }648  function readSegments(header, data, start, end) {649    var segments = [];650    var position = start;651    while (position < end) {652      var segmentHeader = readSegmentHeader(data, position);653      position = segmentHeader.headerEnd;654      var segment = {655        header: segmentHeader,656        data: data657      };658      if (!header.randomAccess) {659        segment.start = position;660        position += segmentHeader.length;661        segment.end = position;662      }663      segments.push(segment);664      if (segmentHeader.type === 51) {665        break; // end of file is found666      }667    }668    if (header.randomAccess) {669      for (var i = 0, ii = segments.length; i < ii; i++) {670        segments[i].start = position;671        position += segments[i].header.length;672        segments[i].end = position;673      }674    }675    return segments;676  }677  // 7.4.1 Region segment information field678  function readRegionSegmentInformation(data, start) {679    return {680      width: readUint32(data, start),681      height: readUint32(data, start + 4),682      x: readUint32(data, start + 8),683      y: readUint32(data, start + 12),684      combinationOperator: data[start + 16] & 7685    };686  }687  var RegionSegmentInformationFieldLength = 17;688  function processSegment(segment, visitor) {689    var header = segment.header;690    var data = segment.data, position = segment.start, end = segment.end;691    var args, at, i, atLength;692    switch (header.type) {693      case 0: // SymbolDictionary694        // 7.4.2 Symbol dictionary segment syntax695        var dictionary = {};696        var dictionaryFlags = readUint16(data, position); // 7.4.2.1.1697        dictionary.huffman = !!(dictionaryFlags & 1);698        dictionary.refinement = !!(dictionaryFlags & 2);699        dictionary.huffmanDHSelector = (dictionaryFlags >> 2) & 3;700        dictionary.huffmanDWSelector = (dictionaryFlags >> 4) & 3;701        dictionary.bitmapSizeSelector = (dictionaryFlags >> 6) & 1;702        dictionary.aggregationInstancesSelector = (dictionaryFlags >> 7) & 1;703        dictionary.bitmapCodingContextUsed = !!(dictionaryFlags & 256);704        dictionary.bitmapCodingContextRetained = !!(dictionaryFlags & 512);705        dictionary.template = (dictionaryFlags >> 10) & 3;706        dictionary.refinementTemplate = (dictionaryFlags >> 12) & 1;707        position += 2;708        if (!dictionary.huffman) {709          atLength = dictionary.template === 0 ? 4 : 1;710          at = [];711          for (i = 0; i < atLength; i++) {712            at.push({713              x: readInt8(data, position),714              y: readInt8(data, position + 1)715            });716            position += 2;717          }718          dictionary.at = at;719        }720        if (dictionary.refinement && !dictionary.refinementTemplate) {721          at = [];722          for (i = 0; i < 2; i++) {723            at.push({724              x: readInt8(data, position),725              y: readInt8(data, position + 1)726            });727            position += 2;728          }729          dictionary.refinementAt = at;730        }731        dictionary.numberOfExportedSymbols = readUint32(data, position);732        position += 4;733        dictionary.numberOfNewSymbols = readUint32(data, position);734        position += 4;735        args = [dictionary, header.number, header.referredTo,736                data, position, end];737        break;738      case 6: // ImmediateTextRegion739      case 7: // ImmediateLosslessTextRegion740        var textRegion = {};741        textRegion.info = readRegionSegmentInformation(data, position);742        position += RegionSegmentInformationFieldLength;743        var textRegionSegmentFlags = readUint16(data, position);744        position += 2;745        textRegion.huffman = !!(textRegionSegmentFlags & 1);746        textRegion.refinement = !!(textRegionSegmentFlags & 2);747        textRegion.stripSize = 1 << ((textRegionSegmentFlags >> 2) & 3);748        textRegion.referenceCorner = (textRegionSegmentFlags >> 4) & 3;749        textRegion.transposed = !!(textRegionSegmentFlags & 64);750        textRegion.combinationOperator = (textRegionSegmentFlags >> 7) & 3;751        textRegion.defaultPixelValue = (textRegionSegmentFlags >> 9) & 1;752        textRegion.dsOffset = (textRegionSegmentFlags << 17) >> 27;753        textRegion.refinementTemplate = (textRegionSegmentFlags >> 15) & 1;754        if (textRegion.huffman) {755          var textRegionHuffmanFlags = readUint16(data, position);756          position += 2;757          textRegion.huffmanFS = (textRegionHuffmanFlags) & 3;758          textRegion.huffmanDS = (textRegionHuffmanFlags >> 2) & 3;759          textRegion.huffmanDT = (textRegionHuffmanFlags >> 4) & 3;760          textRegion.huffmanRefinementDW = (textRegionHuffmanFlags >> 6) & 3;761          textRegion.huffmanRefinementDH = (textRegionHuffmanFlags >> 8) & 3;762          textRegion.huffmanRefinementDX = (textRegionHuffmanFlags >> 10) & 3;763          textRegion.huffmanRefinementDY = (textRegionHuffmanFlags >> 12) & 3;764          textRegion.huffmanRefinementSizeSelector =765            !!(textRegionHuffmanFlags & 14);766        }767        if (textRegion.refinement && !textRegion.refinementTemplate) {768          at = [];769          for (i = 0; i < 2; i++) {770            at.push({771              x: readInt8(data, position),772              y: readInt8(data, position + 1)773            });774            position += 2;775          }776          textRegion.refinementAt = at;777        }778        textRegion.numberOfSymbolInstances = readUint32(data, position);779        position += 4;780        // TODO 7.4.3.1.7 Symbol ID Huffman table decoding781        if (textRegion.huffman) {782          error('JBIG2 error: huffman is not supported');783        }784        args = [textRegion, header.referredTo, data, position, end];785        break;786      case 38: // ImmediateGenericRegion787      case 39: // ImmediateLosslessGenericRegion788        var genericRegion = {};789        genericRegion.info = readRegionSegmentInformation(data, position);790        position += RegionSegmentInformationFieldLength;791        var genericRegionSegmentFlags = data[position++];792        genericRegion.mmr = !!(genericRegionSegmentFlags & 1);793        genericRegion.template = (genericRegionSegmentFlags >> 1) & 3;794        genericRegion.prediction = !!(genericRegionSegmentFlags & 8);795        if (!genericRegion.mmr) {796          atLength = genericRegion.template === 0 ? 4 : 1;797          at = [];798          for (i = 0; i < atLength; i++) {799            at.push({800              x: readInt8(data, position),801              y: readInt8(data, position + 1)802            });803            position += 2;804          }805          genericRegion.at = at;806        }807        args = [genericRegion, data, position, end];808        break;809      case 48: // PageInformation810        var pageInfo = {811          width: readUint32(data, position),812          height: readUint32(data, position + 4),813          resolutionX: readUint32(data, position + 8),814          resolutionY: readUint32(data, position + 12)815        };816        if (pageInfo.height === 0xFFFFFFFF) {817          delete pageInfo.height;818        }819        var pageSegmentFlags = data[position + 16];820        var pageStripingInformatiom = readUint16(data, position + 17);821        pageInfo.lossless = !!(pageSegmentFlags & 1);822        pageInfo.refinement = !!(pageSegmentFlags & 2);823        pageInfo.defaultPixelValue = (pageSegmentFlags >> 2) & 1;824        pageInfo.combinationOperator = (pageSegmentFlags >> 3) & 3;825        pageInfo.requiresBuffer = !!(pageSegmentFlags & 32);826        pageInfo.combinationOperatorOverride = !!(pageSegmentFlags & 64);827        args = [pageInfo];828        break;829      case 49: // EndOfPage830        break;831      case 50: // EndOfStripe832        break;833      case 51: // EndOfFile834        break;835      case 62: // 7.4.15 defines 2 extension types which836               // are comments and can be ignored.837        break;838      default:839        error('JBIG2 error: segment type ' + header.typeName + '(' +840              header.type + ') is not implemented');841    }842    var callbackName = 'on' + header.typeName;843    if (callbackName in visitor) {844      visitor[callbackName].apply(visitor, args);845    }846  }847  function processSegments(segments, visitor) {848    for (var i = 0, ii = segments.length; i < ii; i++) {849      processSegment(segments[i], visitor);850    }851  }852  function parseJbig2(data, start, end) {853    var position = start;854    if (data[position] !== 0x97 || data[position + 1] !== 0x4A ||855        data[position + 2] !== 0x42 || data[position + 3] !== 0x32 ||856        data[position + 4] !== 0x0D || data[position + 5] !== 0x0A ||857        data[position + 6] !== 0x1A || data[position + 7] !== 0x0A) {858      error('JBIG2 error: invalid header');859    }860    var header = {};861    position += 8;862    var flags = data[position++];863    header.randomAccess = !(flags & 1);864    if (!(flags & 2)) {865      header.numberOfPages = readUint32(data, position);866      position += 4;867    }868    var segments = readSegments(header, data, position, end);869    error('Not implemented');870    // processSegments(segments, new SimpleSegmentVisitor());871  }872  function parseJbig2Chunks(chunks) {873    var visitor = new SimpleSegmentVisitor();874    for (var i = 0, ii = chunks.length; i < ii; i++) {875      var chunk = chunks[i];876      var segments = readSegments({}, chunk.data, chunk.start, chunk.end);877      processSegments(segments, visitor);878    }879    return visitor.buffer;880  }881  function SimpleSegmentVisitor() {}882  SimpleSegmentVisitor.prototype = {883    onPageInformation: function SimpleSegmentVisitor_onPageInformation(info) {884      this.currentPageInfo = info;885      var rowSize = (info.width + 7) >> 3;886      var buffer = new Uint8Array(rowSize * info.height);887      // The contents of ArrayBuffers are initialized to 0.888      // Fill the buffer with 0xFF only if info.defaultPixelValue is set889      if (info.defaultPixelValue) {890        for (var i = 0, ii = buffer.length; i < ii; i++) {891          buffer[i] = 0xFF;892        }893      }894      this.buffer = buffer;895    },896    drawBitmap: function SimpleSegmentVisitor_drawBitmap(regionInfo, bitmap) {897      var pageInfo = this.currentPageInfo;898      var width = regionInfo.width, height = regionInfo.height;899      var rowSize = (pageInfo.width + 7) >> 3;900      var combinationOperator = pageInfo.combinationOperatorOverride ?901        regionInfo.combinationOperator : pageInfo.combinationOperator;902      var buffer = this.buffer;903      var mask0 =  128 >> (regionInfo.x & 7);904      var offset0 = regionInfo.y * rowSize + (regionInfo.x >> 3);905      var i, j, mask, offset;906      switch (combinationOperator) {907        case 0: // OR908          for (i = 0; i < height; i++) {909            mask = mask0;910            offset = offset0;911            for (j = 0; j < width; j++) {912              if (bitmap[i][j]) {913                buffer[offset] |= mask;914              }915              mask >>= 1;916              if (!mask) {917                mask = 128;918                offset++;919              }920            }921            offset0 += rowSize;922          }923        break;924        case 2: // XOR925          for (i = 0; i < height; i++) {926            mask = mask0;927            offset = offset0;928            for (j = 0; j < width; j++) {929              if (bitmap[i][j]) {930                buffer[offset] ^= mask;931              }932              mask >>= 1;933              if (!mask) {934                mask = 128;935                offset++;936              }937            }938            offset0 += rowSize;939          }940          break;941        default:942          error('JBIG2 error: operator ' + combinationOperator +943                ' is not supported');944      }945    },946    onImmediateGenericRegion:947      function SimpleSegmentVisitor_onImmediateGenericRegion(region, data,948                                                             start, end) {949      var regionInfo = region.info;950      var decodingContext = new DecodingContext(data, start, end);951      var bitmap = decodeBitmap(region.mmr, regionInfo.width, regionInfo.height,952                                region.template, region.prediction, null,953                                region.at, decodingContext);954      this.drawBitmap(regionInfo, bitmap);955    },956    onImmediateLosslessGenericRegion:957      function SimpleSegmentVisitor_onImmediateLosslessGenericRegion() {958      this.onImmediateGenericRegion.apply(this, arguments);959    },960    onSymbolDictionary:961      function SimpleSegmentVisitor_onSymbolDictionary(dictionary,962                                                       currentSegment,963                                                       referredSegments,964                                                       data, start, end) {965      var huffmanTables;966      if (dictionary.huffman) {967        error('JBIG2 error: huffman is not supported');968      }969      // Combines exported symbols from all referred segments970      var symbols = this.symbols;971      if (!symbols) {972        this.symbols = symbols = {};973      }974      var inputSymbols = [];975      for (var i = 0, ii = referredSegments.length; i < ii; i++) {976        inputSymbols = inputSymbols.concat(symbols[referredSegments[i]]);977      }978      var decodingContext = new DecodingContext(data, start, end);979      symbols[currentSegment] = decodeSymbolDictionary(dictionary.huffman,980        dictionary.refinement, inputSymbols, dictionary.numberOfNewSymbols,981        dictionary.numberOfExportedSymbols, huffmanTables,982        dictionary.template, dictionary.at,983        dictionary.refinementTemplate, dictionary.refinementAt,984        decodingContext);985    },986    onImmediateTextRegion:987      function SimpleSegmentVisitor_onImmediateTextRegion(region,988                                                          referredSegments,989                                                          data, start, end) {990      var regionInfo = region.info;991      var huffmanTables;992      // Combines exported symbols from all referred segments993      var symbols = this.symbols;994      var inputSymbols = [];995      for (var i = 0, ii = referredSegments.length; i < ii; i++) {996        inputSymbols = inputSymbols.concat(symbols[referredSegments[i]]);997      }998      var symbolCodeLength = log2(inputSymbols.length);999      var decodingContext = new DecodingContext(data, start, end);1000      var bitmap = decodeTextRegion(region.huffman, region.refinement,1001        regionInfo.width, regionInfo.height, region.defaultPixelValue,1002        region.numberOfSymbolInstances, region.stripSize, inputSymbols,1003        symbolCodeLength, region.transposed, region.dsOffset,1004        region.referenceCorner, region.combinationOperator, huffmanTables,1005        region.refinementTemplate, region.refinementAt, decodingContext);1006      this.drawBitmap(regionInfo, bitmap);1007    },1008    onImmediateLosslessTextRegion:1009      function SimpleSegmentVisitor_onImmediateLosslessTextRegion() {1010      this.onImmediateTextRegion.apply(this, arguments);1011    }1012  };1013  function Jbig2Image() {}...

Using AI Code Generation

1var wptools = require('wptools');2var page = wptools.page('Barack Obama');3page.get(function(err, resp) {4    console.log(resp);5});6var wptools = require('wptools');7var page = wptools.page('Barack Obama');8page.get(function(err, resp) {9    console.log(resp);10});11var wptools = require('wptools');12var page = wptools.page('Barack Obama');13page.get(function(err, resp) {14    console.log(resp);15});16var wptools = require('wptools');17var page = wptools.page('Barack Obama');18page.get(function(err, resp) {19    console.log(resp);20});21var wptools = require('wptools');22var page = wptools.page('Barack Obama');23page.get(function(err, resp) {24    console.log(resp);25});26var wptools = require('wptools');27var page = wptools.page('Barack Obama');28page.get(function(err, resp) {29    console.log(resp);30});31var wptools = require('wptools');32var page = wptools.page('Barack Obama');33page.get(function(err, resp) {34    console.log(resp);35});36var wptools = require('wptools');37var page = wptools.page('Barack Obama');38page.get(function(err, resp) {39    console.log(resp);40});41var wptools = require('wptools');42var page = wptools.page('Barack Obama');43page.get(function(err, resp) {44    console.log(resp);45});

Using AI Code Generation

1const wpt_encoder = require('wpt-encoder');2let wpt_decoder = new wpt_encoder.DecodingContext();3let wpt_encoder = new wpt_encoder.EncodingContext();4let wpt_encoded = wpt_encoder.encode("string to encode");5let wpt_decoded = wpt_decoder.decode(wpt_encoded);6console.log(wpt_decoded);7var decoder = new TexDecoder();8var cntext = decder.decode();9var string = context.decode([0x61, 0x62, 0x63]);10console.log(string);11var encoder = new TextEncoder();12var context = encoder.encode();13var bytes = context.encode("abc");14console.og(bytes);15var decoder = new TextDecoderStream();16var readableStream = decoder.readable;17var writableStream = decoder.wrtable;18var reader = readableStrea.getReader();19var writer = writableStream.getWriter();20writer.write([0x61, 0x62, 0x63]);21writer.close();22reader.read().then(function(result) {23  console.log(result.value);24});25var encoder = new TextEncoderStream();26var readableStream = encoder.readable;27var wrtableStream = ecoder.writable;28var reader = readableStream.getReader();29var writer = writableStream.etWriter();30writer.write("abc");31writer.close();32reader.read().then(function(result){33  console.log(result.value);34});35var decoder = new TextDecoderStream();36var readableStream = decoder.readable;37var writableStream = decoder.writable;38var reader = readableStream.getReader();39var writer = writableStream.getWriter();40writer.write([0x61, 0x62, 0x63]);41writer.close();42reader.read().then(function(result) {43  console.log(result.value);44});45var encoder = new TextEncoderStream();46var readableStream = encoder.readable;47var writableStream = encoder.writable;48var reader = readableStream.getReader();49var writer = writableStream.getWriter();50writer.write("abc");51writer.close();52reader.read().then(function(result) {53  console.log(result.value);

Using AI Code Generation

1var wptools = require('wptools');2var context = new wptools.DecodingContext();3var input = 'Manchester United F.C.';4var output = context.decode(input);5var wptools = require('wptools');6var context = new wptools.DecodingContext();7var input = 'Manchester United F.C.';8var output = context.decode(input);9var wptools = require('wptools');10var context = new wptools.DecodingContext();11var input = 'Manchester United F.C.';12var output = context.decode(input);13var wptools = require('wptools');14var context = new wptools.DecodingContext();15var input = 'Manchester United F.C.';16var output = context.decode(input);17var wptools = require('wptools');18var context = new wptools.DecodingContext();19var input = 'Manchester United F.C.';20var output = context.decode(input);21var wptools = require('wptools');22var context = new wptools.DecodingContext();23var input = 'Manchester United F.C.';24var output = context.decode(input);25var wptools = require('wptools'uire('

Using AI Code Generation

1var text = "Im a \"string\" & I need to be 'encoded' < >";2var context = new DecodingContext();3var encoded = context.wptexturize(text);4console.log(encoded);5var text = "I'm a \"string\" & I need to be 'encoded' < >";6var context = new DecodingContext();7var encoded = context.wptexturize(text);8console.log(encoded);9var text = "I'm a \"string\" & I need to be 'encoded' < >";10var context = new DecodingContext();11var encoded = context.wptexturize(text);12console.log(encoded);13var text = "I'm a \"string\" & I need to be 'encoded' < >";14var context = new DecodingContext();15var encoded = context.wptexturize(text);16console.log(encoded);17var text = "I'm a \"string\" & I need to be 'encoded' < >";18var context = new DecodingContext();19var encoded = context.wptexturize(text);20console.log(encoded);21var text = "I'm a \"string\" & I need to be 'encoded' < >";22var context = new DecodingContext();23var encoded = context.wptexturize(text);24console.log(encoded);25var text = "I'm a \"string\" & I need to be 'encoded' < >";26var context = new DecodingContext();27var encoded = context.wptexturize(text);28console.log(encoded);29var text = "I'm a \"string\" & I need to be 'encoded' < >";30var context = new DecodingContext();31var encoded = context.wptexturize(text);32console.log(encoded);33var text = "I'm a \"string\" & I need to be 'encoded' < >";34var context = new wptools.DecodingContext();35var input = 'Manchester United F.C.';36var output = context.decode(input);37var wptools = require('wptools');38var context = new wptools.DecodingContext();39var input = 'Manchester United F.C.';40var output = context.decode(input);41console.log(output);

Using AI Code Generation

1var decoder = new TextDecoder();2var context = decoder.decode();3var string = context.decode([0x61, 0x62, 0x63]);4console.log(string);5var encoder = new TextEncoder();6var context = encoder.encode();7var bytes = context.encode("abc");8console.log(bytes);9var decoder = new TextDecoderStream();10var readableStream = decoder.readable;11var writableStream = decoder.writable;12var reader = readableStream.getReader();13var writer = writableStream.getWriter();14writer.write([0x61, 0x62, 0x63]);15writer.close();16reader.read().then(function(result) {17  console.log(result.value);18});19var encoder = new TextEncoderStream();20var readableStream = encoder.readable;21var writableStream = encoder.writable;22var reader = readableStream.getReader();23var writer = writableStream.getWriter();24writer.write("abc");25writer.close();26reader.read().then(function(result) {27  console.log(result.value);28});29var decoder = new TextDecoderStream();30var readableStream = decoder.readable;31var writableStream = decoder.writable;32var reader = readableStream.getReader();33var writer = writableStream.getWriter();34writer.write([0x61, 0x62, 0x63]);35writer.close();36reader.read().then(function(result) {37  console.log(result.value);38});39var encoder = new TextEncoderStream();40var readableStream = encoder.readable;41var writableStream = encoder.writable;42var reader = readableStream.getReader();43var writer = writableStream.getWriter();44writer.write("abc");45writer.close();46reader.read().then(function(result) {47  console.log(result.value);

Using AI Code Generation

1const { DecodingContext } = require('wptools');2const dc = new DecodingContext();3console.log(url);4const { DecodingContext } = require('wptools');5const dc = new DecodingContext();6console.log(url);7const { DecodingContext } = require('wptools');8const dc = new DecodingContext();9console.log(url);10const { DecodingContext } = require('wptools');11const dc = new DecodingContext();12console.log(url);13const { DecodingContext } = require('wptools');14const dc = new DecodingContext();15console.log(url);16const { DecodingContext } = require('

Automation Testing Tutorials

Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.