pdfjs-dist/lib/core/jpg.js

/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';
var sharedUtil = require('../shared/util.js');
var warn = sharedUtil.warn;
var error = sharedUtil.error;
var JpegImage = function JpegImageClosure() {
 var dctZigZag = new Uint8Array([
  0,
  1,
  8,
  16,
  9,
  2,
  3,
  10,
  17,
  24,
  32,
  25,
  18,
  11,
  4,
  5,
  12,
  19,
  26,
  33,
  40,
  48,
  41,
  34,
  27,
  20,
  13,
  6,
  7,
  14,
  21,
  28,
  35,
  42,
  49,
  56,
  57,
  50,
  43,
  36,
  29,
  22,
  15,
  23,
  30,
  37,
  44,
  51,
  58,
  59,
  52,
  45,
  38,
  31,
  39,
  46,
  53,
  60,
  61,
  54,
  47,
  55,
  62,
  63
 ]);
 var dctCos1 = 4017;
 var dctSin1 = 799;
 var dctCos3 = 3406;
 var dctSin3 = 2276;
 var dctCos6 = 1567;
 var dctSin6 = 3784;
 var dctSqrt2 = 5793;
 var dctSqrt1d2 = 2896;
 function JpegImage() {
  this.decodeTransform = null;
  this.colorTransform = -1;
 }
 function buildHuffmanTable(codeLengths, values) {
  var k = 0, code = [], i, j, length = 16;
  while (length > 0 && !codeLengths[length - 1]) {
   length--;
  }
  code.push({
   children: [],
   index: 0
  });
  var p = code[0], q;
  for (i = 0; i < length; i++) {
   for (j = 0; j < codeLengths[i]; j++) {
    p = code.pop();
    p.children[p.index] = values[k];
    while (p.index > 0) {
     p = code.pop();
    }
    p.index++;
    code.push(p);
    while (code.length <= i) {
     code.push(q = {
      children: [],
      index: 0
     });
     p.children[p.index] = q.children;
     p = q;
    }
    k++;
   }
   if (i + 1 < length) {
    code.push(q = {
     children: [],
     index: 0
    });
    p.children[p.index] = q.children;
    p = q;
   }
  }
  return code[0].children;
 }
 function getBlockBufferOffset(component, row, col) {
  return 64 * ((component.blocksPerLine + 1) * row + col);
 }
 function decodeScan(data, offset, frame, components, resetInterval, spectralStart, spectralEnd, successivePrev, successive) {
  var mcusPerLine = frame.mcusPerLine;
  var progressive = frame.progressive;
  var startOffset = offset, bitsData = 0, bitsCount = 0;
  function readBit() {
   if (bitsCount > 0) {
    bitsCount--;
    return bitsData >> bitsCount & 1;
   }
   bitsData = data[offset++];
   if (bitsData === 0xFF) {
    var nextByte = data[offset++];
    if (nextByte) {
     error('JPEG error: unexpected marker ' + (bitsData << 8 | nextByte).toString(16));
    }
   }
   bitsCount = 7;
   return bitsData >>> 7;
  }
  function decodeHuffman(tree) {
   var node = tree;
   while (true) {
    node = node[readBit()];
    if (typeof node === 'number') {
     return node;
    }
    if (typeof node !== 'object') {
     error('JPEG error: invalid huffman sequence');
    }
   }
  }
  function receive(length) {
   var n = 0;
   while (length > 0) {
    n = n << 1 | readBit();
    length--;
   }
   return n;
  }
  function receiveAndExtend(length) {
   if (length === 1) {
    return readBit() === 1 ? 1 : -1;
   }
   var n = receive(length);
   if (n >= 1 << length - 1) {
    return n;
   }
   return n + (-1 << length) + 1;
  }
  function decodeBaseline(component, offset) {
   var t = decodeHuffman(component.huffmanTableDC);
   var diff = t === 0 ? 0 : receiveAndExtend(t);
   component.blockData[offset] = component.pred += diff;
   var k = 1;
   while (k < 64) {
    var rs = decodeHuffman(component.huffmanTableAC);
    var s = rs & 15, r = rs >> 4;
    if (s === 0) {
     if (r < 15) {
      break;
     }
     k += 16;
     continue;
    }
    k += r;
    var z = dctZigZag[k];
    component.blockData[offset + z] = receiveAndExtend(s);
    k++;
   }
  }
  function decodeDCFirst(component, offset) {
   var t = decodeHuffman(component.huffmanTableDC);
   var diff = t === 0 ? 0 : receiveAndExtend(t) << successive;
   component.blockData[offset] = component.pred += diff;
  }
  function decodeDCSuccessive(component, offset) {
   component.blockData[offset] |= readBit() << successive;
  }
  var eobrun = 0;
  function decodeACFirst(component, offset) {
   if (eobrun > 0) {
    eobrun--;
    return;
   }
   var k = spectralStart, e = spectralEnd;
   while (k <= e) {
    var rs = decodeHuffman(component.huffmanTableAC);
    var s = rs & 15, r = rs >> 4;
    if (s === 0) {
     if (r < 15) {
      eobrun = receive(r) + (1 << r) - 1;
      break;
     }
     k += 16;
     continue;
    }
    k += r;
    var z = dctZigZag[k];
    component.blockData[offset + z] = receiveAndExtend(s) * (1 << successive);
    k++;
   }
  }
  var successiveACState = 0, successiveACNextValue;
  function decodeACSuccessive(component, offset) {
   var k = spectralStart;
   var e = spectralEnd;
   var r = 0;
   var s;
   var rs;
   while (k <= e) {
    var z = dctZigZag[k];
    switch (successiveACState) {
    case 0:
     rs = decodeHuffman(component.huffmanTableAC);
     s = rs & 15;
     r = rs >> 4;
     if (s === 0) {
      if (r < 15) {
       eobrun = receive(r) + (1 << r);
       successiveACState = 4;
      } else {
       r = 16;
       successiveACState = 1;
      }
     } else {
      if (s !== 1) {
       error('JPEG error: invalid ACn encoding');
      }
      successiveACNextValue = receiveAndExtend(s);
      successiveACState = r ? 2 : 3;
     }
     continue;
    case 1:
    case 2:
     if (component.blockData[offset + z]) {
      component.blockData[offset + z] += readBit() << successive;
     } else {
      r--;
      if (r === 0) {
       successiveACState = successiveACState === 2 ? 3 : 0;
      }
     }
     break;
    case 3:
     if (component.blockData[offset + z]) {
      component.blockData[offset + z] += readBit() << successive;
     } else {
      component.blockData[offset + z] = successiveACNextValue << successive;
      successiveACState = 0;
     }
     break;
    case 4:
     if (component.blockData[offset + z]) {
      component.blockData[offset + z] += readBit() << successive;
     }
     break;
    }
    k++;
   }
   if (successiveACState === 4) {
    eobrun--;
    if (eobrun === 0) {
     successiveACState = 0;
    }
   }
  }
  function decodeMcu(component, decode, mcu, row, col) {
   var mcuRow = mcu / mcusPerLine | 0;
   var mcuCol = mcu % mcusPerLine;
   var blockRow = mcuRow * component.v + row;
   var blockCol = mcuCol * component.h + col;
   var offset = getBlockBufferOffset(component, blockRow, blockCol);
   decode(component, offset);
  }
  function decodeBlock(component, decode, mcu) {
   var blockRow = mcu / component.blocksPerLine | 0;
   var blockCol = mcu % component.blocksPerLine;
   var offset = getBlockBufferOffset(component, blockRow, blockCol);
   decode(component, offset);
  }
  var componentsLength = components.length;
  var component, i, j, k, n;
  var decodeFn;
  if (progressive) {
   if (spectralStart === 0) {
    decodeFn = successivePrev === 0 ? decodeDCFirst : decodeDCSuccessive;
   } else {
    decodeFn = successivePrev === 0 ? decodeACFirst : decodeACSuccessive;
   }
  } else {
   decodeFn = decodeBaseline;
  }
  var mcu = 0, marker;
  var mcuExpected;
  if (componentsLength === 1) {
   mcuExpected = components[0].blocksPerLine * components[0].blocksPerColumn;
  } else {
   mcuExpected = mcusPerLine * frame.mcusPerColumn;
  }
  var h, v;
  while (mcu < mcuExpected) {
   var mcuToRead = resetInterval ? Math.min(mcuExpected - mcu, resetInterval) : mcuExpected;
   for (i = 0; i < componentsLength; i++) {
    components[i].pred = 0;
   }
   eobrun = 0;
   if (componentsLength === 1) {
    component = components[0];
    for (n = 0; n < mcuToRead; n++) {
     decodeBlock(component, decodeFn, mcu);
     mcu++;
    }
   } else {
    for (n = 0; n < mcuToRead; n++) {
     for (i = 0; i < componentsLength; i++) {
      component = components[i];
      h = component.h;
      v = component.v;
      for (j = 0; j < v; j++) {
       for (k = 0; k < h; k++) {
        decodeMcu(component, decodeFn, mcu, j, k);
       }
      }
     }
     mcu++;
    }
   }
   bitsCount = 0;
   marker = data[offset] << 8 | data[offset + 1];
   while (data[offset] === 0x00 && offset < data.length - 1) {
    offset++;
    marker = data[offset] << 8 | data[offset + 1];
   }
   if (marker <= 0xFF00) {
    error('JPEG error: marker was not found');
   }
   if (marker >= 0xFFD0 && marker <= 0xFFD7) {
    offset += 2;
   } else {
    break;
   }
  }
  return offset - startOffset;
 }
 function quantizeAndInverse(component, blockBufferOffset, p) {
  var qt = component.quantizationTable, blockData = component.blockData;
  var v0, v1, v2, v3, v4, v5, v6, v7;
  var p0, p1, p2, p3, p4, p5, p6, p7;
  var t;
  if (!qt) {
   error('JPEG error: missing required Quantization Table.');
  }
  for (var row = 0; row < 64; row += 8) {
   p0 = blockData[blockBufferOffset + row];
   p1 = blockData[blockBufferOffset + row + 1];
   p2 = blockData[blockBufferOffset + row + 2];
   p3 = blockData[blockBufferOffset + row + 3];
   p4 = blockData[blockBufferOffset + row + 4];
   p5 = blockData[blockBufferOffset + row + 5];
   p6 = blockData[blockBufferOffset + row + 6];
   p7 = blockData[blockBufferOffset + row + 7];
   p0 *= qt[row];
   if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {
    t = dctSqrt2 * p0 + 512 >> 10;
    p[row] = t;
    p[row + 1] = t;
    p[row + 2] = t;
    p[row + 3] = t;
    p[row + 4] = t;
    p[row + 5] = t;
    p[row + 6] = t;
    p[row + 7] = t;
    continue;
   }
   p1 *= qt[row + 1];
   p2 *= qt[row + 2];
   p3 *= qt[row + 3];
   p4 *= qt[row + 4];
   p5 *= qt[row + 5];
   p6 *= qt[row + 6];
   p7 *= qt[row + 7];
   v0 = dctSqrt2 * p0 + 128 >> 8;
   v1 = dctSqrt2 * p4 + 128 >> 8;
   v2 = p2;
   v3 = p6;
   v4 = dctSqrt1d2 * (p1 - p7) + 128 >> 8;
   v7 = dctSqrt1d2 * (p1 + p7) + 128 >> 8;
   v5 = p3 << 4;
   v6 = p5 << 4;
   v0 = v0 + v1 + 1 >> 1;
   v1 = v0 - v1;
   t = v2 * dctSin6 + v3 * dctCos6 + 128 >> 8;
   v2 = v2 * dctCos6 - v3 * dctSin6 + 128 >> 8;
   v3 = t;
   v4 = v4 + v6 + 1 >> 1;
   v6 = v4 - v6;
   v7 = v7 + v5 + 1 >> 1;
   v5 = v7 - v5;
   v0 = v0 + v3 + 1 >> 1;
   v3 = v0 - v3;
   v1 = v1 + v2 + 1 >> 1;
   v2 = v1 - v2;
   t = v4 * dctSin3 + v7 * dctCos3 + 2048 >> 12;
   v4 = v4 * dctCos3 - v7 * dctSin3 + 2048 >> 12;
   v7 = t;
   t = v5 * dctSin1 + v6 * dctCos1 + 2048 >> 12;
   v5 = v5 * dctCos1 - v6 * dctSin1 + 2048 >> 12;
   v6 = t;
   p[row] = v0 + v7;
   p[row + 7] = v0 - v7;
   p[row + 1] = v1 + v6;
   p[row + 6] = v1 - v6;
   p[row + 2] = v2 + v5;
   p[row + 5] = v2 - v5;
   p[row + 3] = v3 + v4;
   p[row + 4] = v3 - v4;
  }
  for (var col = 0; col < 8; ++col) {
   p0 = p[col];
   p1 = p[col + 8];
   p2 = p[col + 16];
   p3 = p[col + 24];
   p4 = p[col + 32];
   p5 = p[col + 40];
   p6 = p[col + 48];
   p7 = p[col + 56];
   if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {
    t = dctSqrt2 * p0 + 8192 >> 14;
    t = t < -2040 ? 0 : t >= 2024 ? 255 : t + 2056 >> 4;
    blockData[blockBufferOffset + col] = t;
    blockData[blockBufferOffset + col + 8] = t;
    blockData[blockBufferOffset + col + 16] = t;
    blockData[blockBufferOffset + col + 24] = t;
    blockData[blockBufferOffset + col + 32] = t;
    blockData[blockBufferOffset + col + 40] = t;
    blockData[blockBufferOffset + col + 48] = t;
    blockData[blockBufferOffset + col + 56] = t;
    continue;
   }
   v0 = dctSqrt2 * p0 + 2048 >> 12;
   v1 = dctSqrt2 * p4 + 2048 >> 12;
   v2 = p2;
   v3 = p6;
   v4 = dctSqrt1d2 * (p1 - p7) + 2048 >> 12;
   v7 = dctSqrt1d2 * (p1 + p7) + 2048 >> 12;
   v5 = p3;
   v6 = p5;
   v0 = (v0 + v1 + 1 >> 1) + 4112;
   v1 = v0 - v1;
   t = v2 * dctSin6 + v3 * dctCos6 + 2048 >> 12;
   v2 = v2 * dctCos6 - v3 * dctSin6 + 2048 >> 12;
   v3 = t;
   v4 = v4 + v6 + 1 >> 1;
   v6 = v4 - v6;
   v7 = v7 + v5 + 1 >> 1;
   v5 = v7 - v5;
   v0 = v0 + v3 + 1 >> 1;
   v3 = v0 - v3;
   v1 = v1 + v2 + 1 >> 1;
   v2 = v1 - v2;
   t = v4 * dctSin3 + v7 * dctCos3 + 2048 >> 12;
   v4 = v4 * dctCos3 - v7 * dctSin3 + 2048 >> 12;
   v7 = t;
   t = v5 * dctSin1 + v6 * dctCos1 + 2048 >> 12;
   v5 = v5 * dctCos1 - v6 * dctSin1 + 2048 >> 12;
   v6 = t;
   p0 = v0 + v7;
   p7 = v0 - v7;
   p1 = v1 + v6;
   p6 = v1 - v6;
   p2 = v2 + v5;
   p5 = v2 - v5;
   p3 = v3 + v4;
   p4 = v3 - v4;
   p0 = p0 < 16 ? 0 : p0 >= 4080 ? 255 : p0 >> 4;
   p1 = p1 < 16 ? 0 : p1 >= 4080 ? 255 : p1 >> 4;
   p2 = p2 < 16 ? 0 : p2 >= 4080 ? 255 : p2 >> 4;
   p3 = p3 < 16 ? 0 : p3 >= 4080 ? 255 : p3 >> 4;
   p4 = p4 < 16 ? 0 : p4 >= 4080 ? 255 : p4 >> 4;
   p5 = p5 < 16 ? 0 : p5 >= 4080 ? 255 : p5 >> 4;
   p6 = p6 < 16 ? 0 : p6 >= 4080 ? 255 : p6 >> 4;
   p7 = p7 < 16 ? 0 : p7 >= 4080 ? 255 : p7 >> 4;
   blockData[blockBufferOffset + col] = p0;
   blockData[blockBufferOffset + col + 8] = p1;
   blockData[blockBufferOffset + col + 16] = p2;
   blockData[blockBufferOffset + col + 24] = p3;
   blockData[blockBufferOffset + col + 32] = p4;
   blockData[blockBufferOffset + col + 40] = p5;
   blockData[blockBufferOffset + col + 48] = p6;
   blockData[blockBufferOffset + col + 56] = p7;
  }
 }
 function buildComponentData(frame, component) {
  var blocksPerLine = component.blocksPerLine;
  var blocksPerColumn = component.blocksPerColumn;
  var computationBuffer = new Int16Array(64);
  for (var blockRow = 0; blockRow < blocksPerColumn; blockRow++) {
   for (var blockCol = 0; blockCol < blocksPerLine; blockCol++) {
    var offset = getBlockBufferOffset(component, blockRow, blockCol);
    quantizeAndInverse(component, offset, computationBuffer);
   }
  }
  return component.blockData;
 }
 function clamp0to255(a) {
  return a <= 0 ? 0 : a >= 255 ? 255 : a;
 }
 JpegImage.prototype = {
  parse: function parse(data) {
   function readUint16() {
    var value = data[offset] << 8 | data[offset + 1];
    offset += 2;
    return value;
   }
   function readDataBlock() {
    function isValidMarkerAt(pos) {
     if (pos < data.length - 1) {
      return data[pos] === 0xFF && data[pos + 1] >= 0xC0 && data[pos + 1] <= 0xFE;
     }
     return true;
    }
    var length = readUint16();
    var endOffset = offset + length - 2;
    if (!isValidMarkerAt(endOffset)) {
     warn('readDataBlock - incorrect length, next marker is: ' + (data[endOffset] << 8 | data[endOffset + 1]).toString('16'));
     var pos = offset;
     while (!isValidMarkerAt(pos)) {
      pos++;
     }
     endOffset = pos;
    }
    var array = data.subarray(offset, endOffset);
    offset += array.length;
    return array;
   }
   function prepareComponents(frame) {
    var mcusPerLine = Math.ceil(frame.samplesPerLine / 8 / frame.maxH);
    var mcusPerColumn = Math.ceil(frame.scanLines / 8 / frame.maxV);
    for (var i = 0; i < frame.components.length; i++) {
     component = frame.components[i];
     var blocksPerLine = Math.ceil(Math.ceil(frame.samplesPerLine / 8) * component.h / frame.maxH);
     var blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines / 8) * component.v / frame.maxV);
     var blocksPerLineForMcu = mcusPerLine * component.h;
     var blocksPerColumnForMcu = mcusPerColumn * component.v;
     var blocksBufferSize = 64 * blocksPerColumnForMcu * (blocksPerLineForMcu + 1);
     component.blockData = new Int16Array(blocksBufferSize);
     component.blocksPerLine = blocksPerLine;
     component.blocksPerColumn = blocksPerColumn;
    }
    frame.mcusPerLine = mcusPerLine;
    frame.mcusPerColumn = mcusPerColumn;
   }
   var offset = 0;
   var jfif = null;
   var adobe = null;
   var frame, resetInterval;
   var quantizationTables = [];
   var huffmanTablesAC = [], huffmanTablesDC = [];
   var fileMarker = readUint16();
   if (fileMarker !== 0xFFD8) {
    error('JPEG error: SOI not found');
   }
   fileMarker = readUint16();
   while (fileMarker !== 0xFFD9) {
    var i, j, l;
    switch (fileMarker) {
    case 0xFFE0:
    case 0xFFE1:
    case 0xFFE2:
    case 0xFFE3:
    case 0xFFE4:
    case 0xFFE5:
    case 0xFFE6:
    case 0xFFE7:
    case 0xFFE8:
    case 0xFFE9:
    case 0xFFEA:
    case 0xFFEB:
    case 0xFFEC:
    case 0xFFED:
    case 0xFFEE:
    case 0xFFEF:
    case 0xFFFE:
     var appData = readDataBlock();
     if (fileMarker === 0xFFE0) {
      if (appData[0] === 0x4A && appData[1] === 0x46 && appData[2] === 0x49 && appData[3] === 0x46 && appData[4] === 0) {
       jfif = {
        version: {
         major: appData[5],
         minor: appData[6]
        },
        densityUnits: appData[7],
        xDensity: appData[8] << 8 | appData[9],
        yDensity: appData[10] << 8 | appData[11],
        thumbWidth: appData[12],
        thumbHeight: appData[13],
        thumbData: appData.subarray(14, 14 + 3 * appData[12] * appData[13])
       };
      }
     }
     if (fileMarker === 0xFFEE) {
      if (appData[0] === 0x41 && appData[1] === 0x64 && appData[2] === 0x6F && appData[3] === 0x62 && appData[4] === 0x65) {
       adobe = {
        version: appData[5] << 8 | appData[6],
        flags0: appData[7] << 8 | appData[8],
        flags1: appData[9] << 8 | appData[10],
        transformCode: appData[11]
       };
      }
     }
     break;
    case 0xFFDB:
     var quantizationTablesLength = readUint16();
     var quantizationTablesEnd = quantizationTablesLength + offset - 2;
     var z;
     while (offset < quantizationTablesEnd) {
      var quantizationTableSpec = data[offset++];
      var tableData = new Uint16Array(64);
      if (quantizationTableSpec >> 4 === 0) {
       for (j = 0; j < 64; j++) {
        z = dctZigZag[j];
        tableData[z] = data[offset++];
       }
      } else if (quantizationTableSpec >> 4 === 1) {
       for (j = 0; j < 64; j++) {
        z = dctZigZag[j];
        tableData[z] = readUint16();
       }
      } else {
       error('JPEG error: DQT - invalid table spec');
      }
      quantizationTables[quantizationTableSpec & 15] = tableData;
     }
     break;
    case 0xFFC0:
    case 0xFFC1:
    case 0xFFC2:
     if (frame) {
      error('JPEG error: Only single frame JPEGs supported');
     }
     readUint16();
     frame = {};
     frame.extended = fileMarker === 0xFFC1;
     frame.progressive = fileMarker === 0xFFC2;
     frame.precision = data[offset++];
     frame.scanLines = readUint16();
     frame.samplesPerLine = readUint16();
     frame.components = [];
     frame.componentIds = {};
     var componentsCount = data[offset++], componentId;
     var maxH = 0, maxV = 0;
     for (i = 0; i < componentsCount; i++) {
      componentId = data[offset];
      var h = data[offset + 1] >> 4;
      var v = data[offset + 1] & 15;
      if (maxH < h) {
       maxH = h;
      }
      if (maxV < v) {
       maxV = v;
      }
      var qId = data[offset + 2];
      l = frame.components.push({
       h: h,
       v: v,
       quantizationId: qId,
       quantizationTable: null
      });
      frame.componentIds[componentId] = l - 1;
      offset += 3;
     }
     frame.maxH = maxH;
     frame.maxV = maxV;
     prepareComponents(frame);
     break;
    case 0xFFC4:
     var huffmanLength = readUint16();
     for (i = 2; i < huffmanLength;) {
      var huffmanTableSpec = data[offset++];
      var codeLengths = new Uint8Array(16);
      var codeLengthSum = 0;
      for (j = 0; j < 16; j++, offset++) {
       codeLengthSum += codeLengths[j] = data[offset];
      }
      var huffmanValues = new Uint8Array(codeLengthSum);
      for (j = 0; j < codeLengthSum; j++, offset++) {
       huffmanValues[j] = data[offset];
      }
      i += 17 + codeLengthSum;
      (huffmanTableSpec >> 4 === 0 ? huffmanTablesDC : huffmanTablesAC)[huffmanTableSpec & 15] = buildHuffmanTable(codeLengths, huffmanValues);
     }
     break;
    case 0xFFDD:
     readUint16();
     resetInterval = readUint16();
     break;
    case 0xFFDA:
     readUint16();
     var selectorsCount = data[offset++];
     var components = [], component;
     for (i = 0; i < selectorsCount; i++) {
      var componentIndex = frame.componentIds[data[offset++]];
      component = frame.components[componentIndex];
      var tableSpec = data[offset++];
      component.huffmanTableDC = huffmanTablesDC[tableSpec >> 4];
      component.huffmanTableAC = huffmanTablesAC[tableSpec & 15];
      components.push(component);
     }
     var spectralStart = data[offset++];
     var spectralEnd = data[offset++];
     var successiveApproximation = data[offset++];
     var processed = decodeScan(data, offset, frame, components, resetInterval, spectralStart, spectralEnd, successiveApproximation >> 4, successiveApproximation & 15);
     offset += processed;
     break;
    case 0xFFFF:
     if (data[offset] !== 0xFF) {
      offset--;
     }
     break;
    default:
     if (data[offset - 3] === 0xFF && data[offset - 2] >= 0xC0 && data[offset - 2] <= 0xFE) {
      offset -= 3;
      break;
     }
     error('JPEG error: unknown marker ' + fileMarker.toString(16));
    }
    fileMarker = readUint16();
   }
   this.width = frame.samplesPerLine;
   this.height = frame.scanLines;
   this.jfif = jfif;
   this.adobe = adobe;
   this.components = [];
   for (i = 0; i < frame.components.length; i++) {
    component = frame.components[i];
    var quantizationTable = quantizationTables[component.quantizationId];
    if (quantizationTable) {
     component.quantizationTable = quantizationTable;
    }
    this.components.push({
     output: buildComponentData(frame, component),
     scaleX: component.h / frame.maxH,
     scaleY: component.v / frame.maxV,
     blocksPerLine: component.blocksPerLine,
     blocksPerColumn: component.blocksPerColumn
    });
   }
   this.numComponents = this.components.length;
  },
  _getLinearizedBlockData: function getLinearizedBlockData(width, height) {
   var scaleX = this.width / width, scaleY = this.height / height;
   var component, componentScaleX, componentScaleY, blocksPerScanline;
   var x, y, i, j, k;
   var index;
   var offset = 0;
   var output;
   var numComponents = this.components.length;
   var dataLength = width * height * numComponents;
   var data = new Uint8Array(dataLength);
   var xScaleBlockOffset = new Uint32Array(width);
   var mask3LSB = 0xfffffff8;
   for (i = 0; i < numComponents; i++) {
    component = this.components[i];
    componentScaleX = component.scaleX * scaleX;
    componentScaleY = component.scaleY * scaleY;
    offset = i;
    output = component.output;
    blocksPerScanline = component.blocksPerLine + 1 << 3;
    for (x = 0; x < width; x++) {
     j = 0 | x * componentScaleX;
     xScaleBlockOffset[x] = (j & mask3LSB) << 3 | j & 7;
    }
    for (y = 0; y < height; y++) {
     j = 0 | y * componentScaleY;
     index = blocksPerScanline * (j & mask3LSB) | (j & 7) << 3;
     for (x = 0; x < width; x++) {
      data[offset] = output[index + xScaleBlockOffset[x]];
      offset += numComponents;
     }
    }
   }
   var transform = this.decodeTransform;
   if (transform) {
    for (i = 0; i < dataLength;) {
     for (j = 0, k = 0; j < numComponents; j++, i++, k += 2) {
      data[i] = (data[i] * transform[k] >> 8) + transform[k + 1];
     }
    }
   }
   return data;
  },
  _isColorConversionNeeded: function isColorConversionNeeded() {
   if (this.adobe && this.adobe.transformCode) {
    return true;
   } else if (this.numComponents === 3) {
    if (!this.adobe && this.colorTransform === 0) {
     return false;
    }
    return true;
   }
   if (!this.adobe && this.colorTransform === 1) {
    return true;
   }
   return false;
  },
  _convertYccToRgb: function convertYccToRgb(data) {
   var Y, Cb, Cr;
   for (var i = 0, length = data.length; i < length; i += 3) {
    Y = data[i];
    Cb = data[i + 1];
    Cr = data[i + 2];
    data[i] = clamp0to255(Y - 179.456 + 1.402 * Cr);
    data[i + 1] = clamp0to255(Y + 135.459 - 0.344 * Cb - 0.714 * Cr);
    data[i + 2] = clamp0to255(Y - 226.816 + 1.772 * Cb);
   }
   return data;
  },
  _convertYcckToRgb: function convertYcckToRgb(data) {
   var Y, Cb, Cr, k;
   var offset = 0;
   for (var i = 0, length = data.length; i < length; i += 4) {
    Y = data[i];
    Cb = data[i + 1];
    Cr = data[i + 2];
    k = data[i + 3];
    var r = -122.67195406894 + Cb * (-6.60635669420364e-5 * Cb + 0.000437130475926232 * Cr - 5.4080610064599e-5 * Y + 0.00048449797120281 * k - 0.154362151871126) + Cr * (-0.000957964378445773 * Cr + 0.000817076911346625 * Y - 0.00477271405408747 * k + 1.53380253221734) + Y * (0.000961250184130688 * Y - 0.00266257332283933 * k + 0.48357088451265) + k * (-0.000336197177618394 * k + 0.484791561490776);
    var g = 107.268039397724 + Cb * (2.19927104525741e-5 * Cb - 0.000640992018297945 * Cr + 0.000659397001245577 * Y + 0.000426105652938837 * k - 0.176491792462875) + Cr * (-0.000778269941513683 * Cr + 0.00130872261408275 * Y + 0.000770482631801132 * k - 0.151051492775562) + Y * (0.00126935368114843 * Y - 0.00265090189010898 * k + 0.25802910206845) + k * (-0.000318913117588328 * k - 0.213742400323665);
    var b = -20.810012546947 + Cb * (-0.000570115196973677 * Cb - 2.63409051004589e-5 * Cr + 0.0020741088115012 * Y - 0.00288260236853442 * k + 0.814272968359295) + Cr * (-1.53496057440975e-5 * Cr - 0.000132689043961446 * Y + 0.000560833691242812 * k - 0.195152027534049) + Y * (0.00174418132927582 * Y - 0.00255243321439347 * k + 0.116935020465145) + k * (-0.000343531996510555 * k + 0.24165260232407);
    data[offset++] = clamp0to255(r);
    data[offset++] = clamp0to255(g);
    data[offset++] = clamp0to255(b);
   }
   return data;
  },
  _convertYcckToCmyk: function convertYcckToCmyk(data) {
   var Y, Cb, Cr;
   for (var i = 0, length = data.length; i < length; i += 4) {
    Y = data[i];
    Cb = data[i + 1];
    Cr = data[i + 2];
    data[i] = clamp0to255(434.456 - Y - 1.402 * Cr);
    data[i + 1] = clamp0to255(119.541 - Y + 0.344 * Cb + 0.714 * Cr);
    data[i + 2] = clamp0to255(481.816 - Y - 1.772 * Cb);
   }
   return data;
  },
  _convertCmykToRgb: function convertCmykToRgb(data) {
   var c, m, y, k;
   var offset = 0;
   var min = -255 * 255 * 255;
   var scale = 1 / 255 / 255;
   for (var i = 0, length = data.length; i < length; i += 4) {
    c = data[i];
    m = data[i + 1];
    y = data[i + 2];
    k = data[i + 3];
    var r = c * (-4.387332384609988 * c + 54.48615194189176 * m + 18.82290502165302 * y + 212.25662451639585 * k - 72734.4411664936) + m * (1.7149763477362134 * m - 5.6096736904047315 * y - 17.873870861415444 * k - 1401.7366389350734) + y * (-2.5217340131683033 * y - 21.248923337353073 * k + 4465.541406466231) - k * (21.86122147463605 * k + 48317.86113160301);
    var g = c * (8.841041422036149 * c + 60.118027045597366 * m + 6.871425592049007 * y + 31.159100130055922 * k - 20220.756542821975) + m * (-15.310361306967817 * m + 17.575251261109482 * y + 131.35250912493976 * k - 48691.05921601825) + y * (4.444339102852739 * y + 9.8632861493405 * k - 6341.191035517494) - k * (20.737325471181034 * k + 47890.15695978492);
    var b = c * (0.8842522430003296 * c + 8.078677503112928 * m + 30.89978309703729 * y - 0.23883238689178934 * k - 3616.812083916688) + m * (10.49593273432072 * m + 63.02378494754052 * y + 50.606957656360734 * k - 28620.90484698408) + y * (0.03296041114873217 * y + 115.60384449646641 * k - 49363.43385999684) - k * (22.33816807309886 * k + 45932.16563550634);
    data[offset++] = r >= 0 ? 255 : r <= min ? 0 : 255 + r * scale | 0;
    data[offset++] = g >= 0 ? 255 : g <= min ? 0 : 255 + g * scale | 0;
    data[offset++] = b >= 0 ? 255 : b <= min ? 0 : 255 + b * scale | 0;
   }
   return data;
  },
  getData: function getData(width, height, forceRGBoutput) {
   if (this.numComponents > 4) {
    error('JPEG error: Unsupported color mode');
   }
   var data = this._getLinearizedBlockData(width, height);
   if (this.numComponents === 1 && forceRGBoutput) {
    var dataLength = data.length;
    var rgbData = new Uint8Array(dataLength * 3);
    var offset = 0;
    for (var i = 0; i < dataLength; i++) {
     var grayColor = data[i];
     rgbData[offset++] = grayColor;
     rgbData[offset++] = grayColor;
     rgbData[offset++] = grayColor;
    }
    return rgbData;
   } else if (this.numComponents === 3 && this._isColorConversionNeeded()) {
    return this._convertYccToRgb(data);
   } else if (this.numComponents === 4) {
    if (this._isColorConversionNeeded()) {
     if (forceRGBoutput) {
      return this._convertYcckToRgb(data);
     }
     return this._convertYcckToCmyk(data);
    } else if (forceRGBoutput) {
     return this._convertCmykToRgb(data);
    }
   }
   return data;
  }
 };
 return JpegImage;
}();
exports.JpegImage = JpegImage;