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;