# Code coverage report for lib\parser.js

## Statements: 90.34% (159 / 176) Branches: 86.11% (62 / 72) Functions: 100% (20 / 20) Lines: 90.34% (159 / 176) Ignored: none

All files » lib/ » parser.js

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221
    222
    223
    224
    225
    226
    227
    228
    229
    230
    231
    232
    233
    234
    235
    236
    237
    238
    239
    240
    241
    242
    243
    244
    245
    246
    247
    248
    249
    250
    251
    252
    253
    254
    255
    256
    257
    258
    259
    260
    261
    262
    263
    264
    265
    266
    267
    268
    269
    270
    271
    272
    273
    274
    275
    276
    277
    278
    279
    280
    281
    282
    283
    284
    285
    286
    287
    288
    289
    290
    291
    292
    293
    294
    295
    296
    297
    298
    299
    300
    301
    302
    303
    304
    305
    306
    307
    308
    309
    310
    311
    312
    313
    314
    315
    316
    317
    318
    319
    320
    321
    322
    323
    324
    325
    326
    327
    328
    329
    330
    331
    332
    333
    334
    335
    336
    337
    338
    339
    340
    341
    342
    343
    344
    345
    346
    347
    348
    349
    350
    351
    352
    353
    354
    355
    356
    357
    358
    359
    360
    361
    362
    363
    364
    365
    366
    367
    368
    369
    370
    371
    372
    373
    374
    375
    376
    377
    378
    379
    380
    381
    382

    1

    1

    511
    511

    511
    511

    511
    511

    511
    511
    511
    511
    511
    511
    511

    511
    511
    511
    511
    511
    511
    511
    511

    1

    1
    511

    1

    350

    350
    2754
    12
    12

    338

    1

    2326

    2326

    2326
    9304

    2326

    2326

    2326
    2326

    2326
    2088

    238

    238

    1
    238

    1
    2078

    1

    2078

    2078
    4
    4

    2074
    1750

    1
    338

    1

    338

    338

    338
    6
    6

    332
    4
    4

    328

    328

    328

    328

    328
    328

    328

    328

    328

    1
    130

    1

    130

    130

    130
    6828

    130

    1
    22

    1

    22

    22
    12

    12

    12
    2464

    22

    4

    22
    6

    22

    1
    292

    1

    292
    292

    292

    1
    982

    1

    982

    982

    982
    982

    982

    982

    1
    324

    1

    324

    324
    324

    324

    1

    323

    323

    126

    126
    3204

    3204
    103332

    103332

    103332
    413328

    197

    197
    10
    320

    320
    10240
    10240

    10240
    4096
    1834

    6144
    2718

    10240
    4552
    18208

    197
    105
    66

    105
    105

    105
    3360

    3360
    107520
    107520
    430080

    323

     // Copyright (c) 2012 Kuba Niegowski
    //
    // Permission is hereby granted, free of charge, to any person obtaining a copy
    // of this software and associated documentation files (the "Software"), to deal
    // in the Software without restriction, including without limitation the rights
    // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    // copies of the Software, and to permit persons to whom the Software is
    // furnished to do so, subject to the following conditions:
    //
    // The above copyright notice and this permission notice shall be included in
    // all copies or substantial portions of the Software.
    //
    // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    // THE SOFTWARE.

    'use strict';

    var constants = require('./constants'),
      CrcCalculator = require('./crc');

    var Parser = module.exports = function(options, dependencies) {

      this._options = options;
      options.checkCRC = options.checkCRC !== false;

      this._hasIHDR = false;
      this._hasIEND = false;

      // input flags/metadata
      this._palette = [];
      this._colorType = 0;

      this._chunks = {};
      this._chunks[constants.TYPE_IHDR] = this._handleIHDR.bind(this);
      this._chunks[constants.TYPE_IEND] = this._handleIEND.bind(this);
      this._chunks[constants.TYPE_IDAT] = this._handleIDAT.bind(this);
      this._chunks[constants.TYPE_PLTE] = this._handlePLTE.bind(this);
      this._chunks[constants.TYPE_tRNS] = this._handleTRNS.bind(this);
      this._chunks[constants.TYPE_gAMA] = this._handleGAMA.bind(this);

      this.read = dependencies.read;
      this.error = dependencies.error;
      this.metadata = dependencies.metadata;
      this.gamma = dependencies.gamma;
      this.parsed = dependencies.parsed;
      this.createData = dependencies.createData;
      this.inflateData = dependencies.inflateData;
        this.finished = dependencies.finished;
    };

    var colorTypeToBppMap = {
      0: 1,
      2: 3,
      3: 1,
      4: 2,
      6: 4
    };

    Parser.prototype.start = function() {
      this.read(constants.PNG_SIGNATURE.length,
        this._parseSignature.bind(this)
      );
    };

    Parser.prototype._parseSignature = function(data) {

      var signature = constants.PNG_SIGNATURE;

      for (var i = 0; i < signature.length; i++) {
        if (data[i] != signature[i]) {
          this.error(new Error('Invalid file signature'));
          return;
        }
      }
      this.read(8, this._parseChunkBegin.bind(this));
    };

    Parser.prototype._parseChunkBegin = function(data) {

      // chunk content length
      var length = data.readUInt32BE(0);

      // chunk type
      var type = data.readUInt32BE(4),
        name = '';
      for (var i = 4; i < 8; i++) {
        name += String.fromCharCode(data[i]);
      }

      //console.log('chunk ', name, length);

      // chunk flags
      var ancillary  = !!(data[4] & 0x20),  // or critical
        priv       = !!(data[5] & 0x20),  // or public
        safeToCopy = !!(data[7] & 0x20);  // or unsafe

      Iif (!this._hasIHDR && type != constants.TYPE_IHDR) {
        this.error(new Error('Expected IHDR on beggining'));
        return;
      }

      this._crc = new CrcCalculator();
      this._crc.write(new Buffer(name));

      if (this._chunks[type]) {
        return this._chunks[type](length);

      } else Iif (!ancillary) {
        this.error(new Error('Unsupported critical chunk type ' + name));
        return;
      } else {
        this.read(length + 4, this._skipChunk.bind(this));
      }
    };

    Parser.prototype._skipChunk = function(data) {
      this.read(8, this._parseChunkBegin.bind(this));
    };

    Parser.prototype._handleChunkEnd = function() {
      this.read(4, this._parseChunkEnd.bind(this));
    };

    Parser.prototype._parseChunkEnd = function(data) {

      var fileCrc = data.readInt32BE(0),
        calcCrc = this._crc.crc32();

      // check CRC
      if (this._options.checkCRC && calcCrc != fileCrc) {
        this.error(new Error('Crc error - ' + fileCrc + " - " + calcCrc));
        return;
      }

      if (!this._hasIEND) {
        this.read(8, this._parseChunkBegin.bind(this));
      }
    };

    Parser.prototype._handleIHDR = function(length) {
      this.read(length, this._parseIHDR.bind(this));
    };
    Parser.prototype._parseIHDR = function(data) {

      this._crc.write(data);

      var width = data.readUInt32BE(0),
        height = data.readUInt32BE(4),
        depth = data[8],
        colorType = data[9], // bits: 1 palette, 2 color, 4 alpha
        compr = data[10],
        filter = data[11],
        interlace = data[12];

      // console.log('    width', width, 'height', height,
      //     'depth', depth, 'colorType', colorType,
      //     'compr', compr, 'filter', filter, 'interlace', interlace
      // );

      if (depth !== 8 && depth !== 4 && depth !== 2 && depth !== 1 && depth !== 16) {
        this.error(new Error('Unsupported bit depth ' + depth));
        return;
      }
      if (!(colorType in colorTypeToBppMap)) {
        this.error(new Error('Unsupported color type'));
        return;
      }
      Iif (compr != 0) {
        this.error(new Error('Unsupported compression method'));
        return;
      }
      Iif (filter != 0) {
        this.error(new Error('Unsupported filter method'));
        return;
      }
      Iif (interlace != 0 && interlace !== 1) {
        this.error(new Error('Unsupported interlace method'));
        return;
      }

      this._colorType = colorType;

      var bpp = colorTypeToBppMap[this._colorType];
      this.createData(width, height, bpp, depth, interlace);

      this._hasIHDR = true;

      this.metadata({
        width: width,
        height: height,
        depth: depth,
        interlace: interlace,
        palette: !!(colorType & constants.COLOR_PALETTE),
        color: !!(colorType & constants.COLOR_COLOR),
        alpha: !!(colorType & constants.COLOR_ALPHA)
      });

      this._handleChunkEnd();
    };

    Parser.prototype._handlePLTE = function(length) {
      this.read(length, this._parsePLTE.bind(this));
    };
    Parser.prototype._parsePLTE = function(data) {

      this._crc.write(data);

      var entries = Math.floor(data.length / 3);
      // console.log('Palette:', entries);

      for (var i = 0; i < entries; i++) {
        this._palette.push([
          data.readUInt8(i * 3),
          data.readUInt8(i * 3 + 1),
          data.readUInt8(i * 3 + 2 ),
          0xff
        ]);
      }

      this._handleChunkEnd();
    };

    Parser.prototype._handleTRNS = function(length) {
      this.read(length, this._parseTRNS.bind(this));
    };
    Parser.prototype._parseTRNS = function(data) {

      this._crc.write(data);

      // palette
      if (this._colorType == 3) {
        Iif (this._palette.length == 0) {
          this.error(new Error('Transparency chunk must be after palette'));
          return;
        }
        Iif (data.length > this._palette.length) {
          this.error(new Error('More transparent colors than palette size'));
          return;
        }
        for (var i = 0; i < this._palette.length; i++) {
          this._palette[i][3] = i < data.length ? data.readUInt8(i) : 0xff;
        }
      }

      // for colorType 0 (grayscale) and 2 (rgb)
      // there might be one gray/color defined as transparent
      if (this._colorType === 0) {
        // grey, 2 bytes
        this._transColor = [data.readUInt16BE(0)];
      }
      if (this._colorType === 2) {
        this._transColor = [data.readUInt16BE(0), data.readUInt16BE(2), data.readUInt16BE(4)];
      }

      this._handleChunkEnd();
    };

    Parser.prototype._handleGAMA = function(length) {
      this.read(length, this._parseGAMA.bind(this));
    };
    Parser.prototype._parseGAMA = function(data) {

      this._crc.write(data);
      this.gamma(data.readUInt32BE(0) / 100000);

      this._handleChunkEnd();
    };

    Parser.prototype._handleIDAT = function(length) {
      this.read(-length, this._parseIDAT.bind(this, length));
    };
    Parser.prototype._parseIDAT = function(length, data) {

      this._crc.write(data);

      Iif (this._colorType == 3 && this._palette.length == 0)
        throw new Error('Expected palette not found');

      this.inflateData(data);
      length -= data.length;

      Iif (length > 0)
        this._handleIDAT(length);
      else
        this._handleChunkEnd();
    };

    Parser.prototype._handleIEND = function(length) {
      this.read(length, this._parseIEND.bind(this));
    };
    Parser.prototype._parseIEND = function(data) {

      this._crc.write(data);

      this._hasIEND = true;
      this._handleChunkEnd();

      this.finished();
    };

    Parser.prototype.reverseFiltered = function(indata, depth, width, height) {

      var outdata = indata; // only different for 16 bits

      if (this._colorType == 3) { // paletted
        //console.log("paletted");
        // use values from palette
        var pxLineLength = width << 2;

        for (var y = 0; y < height; y++) {
          var pxRowPos = y * pxLineLength;

          for (var x = 0; x < width; x++) {
            var pxPos = pxRowPos + (x << 2),
              color = this._palette[indata[pxPos]];

            Iif (!color) {
              throw new Error("index " + indata[pxPos] + " not in palette");
            }

            for (var i = 0; i < 4; i++)
              indata[pxPos + i] = color[i];
          }
        }
      } else {
        var pxLineLength = width << 2;

        if (this._transColor) {
          for (var y = 0; y < height; y++) {
            var pxRowPos = y * pxLineLength;

            for (var x = 0; x < width; x++) {
              var pxPos = pxRowPos + (x << 2);
              var makeTrans = false;
              //console.log(pxPos);
              if (this._transColor.length === 1) {
                if (this._transColor[0] === indata[pxPos]) {
                  makeTrans = true;
                }
              } else if (this._transColor[0] === indata[pxPos] && this._transColor[1] === indata[pxPos + 1] && this._transColor[2] === indata[pxPos + 2]) {
                makeTrans = true;
              }
              if (makeTrans) {
                for (var i = 0; i < 4; i++) {
                  indata[pxPos + i] = 0;
                }
              }
            }
          }
        }
        if (depth !== 8) {
          if (depth === 16) {
            outdata = new Buffer(width * height * 4);
          }
          //console.log("adjusting");
          var maxOutSample = 255;
          var maxInSample = Math.pow(2, depth) - 1;

          for (var y = 0; y < height; y++) {
            var pxRowPos = y * pxLineLength;

            for (var x = 0; x < width; x++) {
              var pxPos = pxRowPos + (x << 2);
              for (var i = 0; i < 4; i++)
                outdata[pxPos + i] = Math.floor((indata[pxPos + i] * maxOutSample) / maxInSample + 0.5);
            }
          }
        }
      }
      return outdata;
    };