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Generic build of PDF.js library.
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pdfjs-dist/src/stream.js

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/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
'use strict';
var Stream = (function StreamClosure() {
function Stream(arrayBuffer, start, length, dict) {
this.bytes = new Uint8Array(arrayBuffer);
this.start = start || 0;
this.pos = this.start;
this.end = (start + length) || this.bytes.length;
this.dict = dict;
}
// required methods for a stream. if a particular stream does not
// implement these, an error should be thrown
Stream.prototype = {
get length() {
return this.end - this.start;
},
getByte: function stream_getByte() {
if (this.pos >= this.end)
return null;
return this.bytes[this.pos++];
},
// returns subarray of original buffer
// should only be read
getBytes: function stream_getBytes(length) {
var bytes = this.bytes;
var pos = this.pos;
var strEnd = this.end;
if (!length)
return bytes.subarray(pos, strEnd);
var end = pos + length;
if (end > strEnd)
end = strEnd;
this.pos = end;
return bytes.subarray(pos, end);
},
lookChar: function stream_lookChar() {
if (this.pos >= this.end)
return null;
return String.fromCharCode(this.bytes[this.pos]);
},
getChar: function stream_getChar() {
if (this.pos >= this.end)
return null;
return String.fromCharCode(this.bytes[this.pos++]);
},
skip: function stream_skip(n) {
if (!n)
n = 1;
this.pos += n;
},
reset: function stream_reset() {
this.pos = this.start;
},
moveStart: function stream_moveStart() {
this.start = this.pos;
},
makeSubStream: function stream_makeSubstream(start, length, dict) {
return new Stream(this.bytes.buffer, start, length, dict);
},
isStream: true
};
return Stream;
})();
var StringStream = (function StringStreamClosure() {
function StringStream(str) {
var length = str.length;
var bytes = new Uint8Array(length);
for (var n = 0; n < length; ++n)
bytes[n] = str.charCodeAt(n);
Stream.call(this, bytes);
}
StringStream.prototype = Stream.prototype;
return StringStream;
})();
// super class for the decoding streams
var DecodeStream = (function DecodeStreamClosure() {
function DecodeStream() {
this.pos = 0;
this.bufferLength = 0;
this.eof = false;
this.buffer = null;
}
DecodeStream.prototype = {
ensureBuffer: function decodestream_ensureBuffer(requested) {
var buffer = this.buffer;
var current = buffer ? buffer.byteLength : 0;
if (requested < current)
return buffer;
var size = 512;
while (size < requested)
size <<= 1;
var buffer2 = new Uint8Array(size);
for (var i = 0; i < current; ++i)
buffer2[i] = buffer[i];
return (this.buffer = buffer2);
},
getByte: function decodestream_getByte() {
var pos = this.pos;
while (this.bufferLength <= pos) {
if (this.eof)
return null;
this.readBlock();
}
return this.buffer[this.pos++];
},
getBytes: function decodestream_getBytes(length) {
var end, pos = this.pos;
if (length) {
this.ensureBuffer(pos + length);
end = pos + length;
while (!this.eof && this.bufferLength < end)
this.readBlock();
var bufEnd = this.bufferLength;
if (end > bufEnd)
end = bufEnd;
} else {
while (!this.eof)
this.readBlock();
end = this.bufferLength;
// checking if bufferLength is still 0 then
// the buffer has to be initialized
if (!end)
this.buffer = new Uint8Array(0);
}
this.pos = end;
return this.buffer.subarray(pos, end);
},
lookChar: function decodestream_lookChar() {
var pos = this.pos;
while (this.bufferLength <= pos) {
if (this.eof)
return null;
this.readBlock();
}
return String.fromCharCode(this.buffer[this.pos]);
},
getChar: function decodestream_getChar() {
var pos = this.pos;
while (this.bufferLength <= pos) {
if (this.eof)
return null;
this.readBlock();
}
return String.fromCharCode(this.buffer[this.pos++]);
},
makeSubStream: function decodestream_makeSubstream(start, length, dict) {
var end = start + length;
while (this.bufferLength <= end && !this.eof)
this.readBlock();
return new Stream(this.buffer, start, length, dict);
},
skip: function decodestream_skip(n) {
if (!n)
n = 1;
this.pos += n;
},
reset: function decodestream_reset() {
this.pos = 0;
}
};
return DecodeStream;
})();
var FakeStream = (function FakeStreamClosure() {
function FakeStream(stream) {
this.dict = stream.dict;
DecodeStream.call(this);
}
FakeStream.prototype = Object.create(DecodeStream.prototype);
FakeStream.prototype.readBlock = function fakeStreamReadBlock() {
var bufferLength = this.bufferLength;
bufferLength += 1024;
var buffer = this.ensureBuffer(bufferLength);
this.bufferLength = bufferLength;
};
FakeStream.prototype.getBytes = function fakeStreamGetBytes(length) {
var end, pos = this.pos;
if (length) {
this.ensureBuffer(pos + length);
end = pos + length;
while (!this.eof && this.bufferLength < end)
this.readBlock();
var bufEnd = this.bufferLength;
if (end > bufEnd)
end = bufEnd;
} else {
this.eof = true;
end = this.bufferLength;
}
this.pos = end;
return this.buffer.subarray(pos, end);
};
return FakeStream;
})();
var StreamsSequenceStream = (function StreamsSequenceStreamClosure() {
function StreamsSequenceStream(streams) {
this.streams = streams;
DecodeStream.call(this);
}
StreamsSequenceStream.prototype = Object.create(DecodeStream.prototype);
StreamsSequenceStream.prototype.readBlock =
function streamSequenceStreamReadBlock() {
var streams = this.streams;
if (streams.length == 0) {
this.eof = true;
return;
}
var stream = streams.shift();
var chunk = stream.getBytes();
var bufferLength = this.bufferLength;
var newLength = bufferLength + chunk.length;
var buffer = this.ensureBuffer(newLength);
buffer.set(chunk, bufferLength);
this.bufferLength = newLength;
};
return StreamsSequenceStream;
})();
var FlateStream = (function FlateStreamClosure() {
var codeLenCodeMap = new Uint32Array([
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
]);
var lengthDecode = new Uint32Array([
0x00003, 0x00004, 0x00005, 0x00006, 0x00007, 0x00008, 0x00009, 0x0000a,
0x1000b, 0x1000d, 0x1000f, 0x10011, 0x20013, 0x20017, 0x2001b, 0x2001f,
0x30023, 0x3002b, 0x30033, 0x3003b, 0x40043, 0x40053, 0x40063, 0x40073,
0x50083, 0x500a3, 0x500c3, 0x500e3, 0x00102, 0x00102, 0x00102
]);
var distDecode = new Uint32Array([
0x00001, 0x00002, 0x00003, 0x00004, 0x10005, 0x10007, 0x20009, 0x2000d,
0x30011, 0x30019, 0x40021, 0x40031, 0x50041, 0x50061, 0x60081, 0x600c1,
0x70101, 0x70181, 0x80201, 0x80301, 0x90401, 0x90601, 0xa0801, 0xa0c01,
0xb1001, 0xb1801, 0xc2001, 0xc3001, 0xd4001, 0xd6001
]);
var fixedLitCodeTab = [new Uint32Array([
0x70100, 0x80050, 0x80010, 0x80118, 0x70110, 0x80070, 0x80030, 0x900c0,
0x70108, 0x80060, 0x80020, 0x900a0, 0x80000, 0x80080, 0x80040, 0x900e0,
0x70104, 0x80058, 0x80018, 0x90090, 0x70114, 0x80078, 0x80038, 0x900d0,
0x7010c, 0x80068, 0x80028, 0x900b0, 0x80008, 0x80088, 0x80048, 0x900f0,
0x70102, 0x80054, 0x80014, 0x8011c, 0x70112, 0x80074, 0x80034, 0x900c8,
0x7010a, 0x80064, 0x80024, 0x900a8, 0x80004, 0x80084, 0x80044, 0x900e8,
0x70106, 0x8005c, 0x8001c, 0x90098, 0x70116, 0x8007c, 0x8003c, 0x900d8,
0x7010e, 0x8006c, 0x8002c, 0x900b8, 0x8000c, 0x8008c, 0x8004c, 0x900f8,
0x70101, 0x80052, 0x80012, 0x8011a, 0x70111, 0x80072, 0x80032, 0x900c4,
0x70109, 0x80062, 0x80022, 0x900a4, 0x80002, 0x80082, 0x80042, 0x900e4,
0x70105, 0x8005a, 0x8001a, 0x90094, 0x70115, 0x8007a, 0x8003a, 0x900d4,
0x7010d, 0x8006a, 0x8002a, 0x900b4, 0x8000a, 0x8008a, 0x8004a, 0x900f4,
0x70103, 0x80056, 0x80016, 0x8011e, 0x70113, 0x80076, 0x80036, 0x900cc,
0x7010b, 0x80066, 0x80026, 0x900ac, 0x80006, 0x80086, 0x80046, 0x900ec,
0x70107, 0x8005e, 0x8001e, 0x9009c, 0x70117, 0x8007e, 0x8003e, 0x900dc,
0x7010f, 0x8006e, 0x8002e, 0x900bc, 0x8000e, 0x8008e, 0x8004e, 0x900fc,
0x70100, 0x80051, 0x80011, 0x80119, 0x70110, 0x80071, 0x80031, 0x900c2,
0x70108, 0x80061, 0x80021, 0x900a2, 0x80001, 0x80081, 0x80041, 0x900e2,
0x70104, 0x80059, 0x80019, 0x90092, 0x70114, 0x80079, 0x80039, 0x900d2,
0x7010c, 0x80069, 0x80029, 0x900b2, 0x80009, 0x80089, 0x80049, 0x900f2,
0x70102, 0x80055, 0x80015, 0x8011d, 0x70112, 0x80075, 0x80035, 0x900ca,
0x7010a, 0x80065, 0x80025, 0x900aa, 0x80005, 0x80085, 0x80045, 0x900ea,
0x70106, 0x8005d, 0x8001d, 0x9009a, 0x70116, 0x8007d, 0x8003d, 0x900da,
0x7010e, 0x8006d, 0x8002d, 0x900ba, 0x8000d, 0x8008d, 0x8004d, 0x900fa,
0x70101, 0x80053, 0x80013, 0x8011b, 0x70111, 0x80073, 0x80033, 0x900c6,
0x70109, 0x80063, 0x80023, 0x900a6, 0x80003, 0x80083, 0x80043, 0x900e6,
0x70105, 0x8005b, 0x8001b, 0x90096, 0x70115, 0x8007b, 0x8003b, 0x900d6,
0x7010d, 0x8006b, 0x8002b, 0x900b6, 0x8000b, 0x8008b, 0x8004b, 0x900f6,
0x70103, 0x80057, 0x80017, 0x8011f, 0x70113, 0x80077, 0x80037, 0x900ce,
0x7010b, 0x80067, 0x80027, 0x900ae, 0x80007, 0x80087, 0x80047, 0x900ee,
0x70107, 0x8005f, 0x8001f, 0x9009e, 0x70117, 0x8007f, 0x8003f, 0x900de,
0x7010f, 0x8006f, 0x8002f, 0x900be, 0x8000f, 0x8008f, 0x8004f, 0x900fe,
0x70100, 0x80050, 0x80010, 0x80118, 0x70110, 0x80070, 0x80030, 0x900c1,
0x70108, 0x80060, 0x80020, 0x900a1, 0x80000, 0x80080, 0x80040, 0x900e1,
0x70104, 0x80058, 0x80018, 0x90091, 0x70114, 0x80078, 0x80038, 0x900d1,
0x7010c, 0x80068, 0x80028, 0x900b1, 0x80008, 0x80088, 0x80048, 0x900f1,
0x70102, 0x80054, 0x80014, 0x8011c, 0x70112, 0x80074, 0x80034, 0x900c9,
0x7010a, 0x80064, 0x80024, 0x900a9, 0x80004, 0x80084, 0x80044, 0x900e9,
0x70106, 0x8005c, 0x8001c, 0x90099, 0x70116, 0x8007c, 0x8003c, 0x900d9,
0x7010e, 0x8006c, 0x8002c, 0x900b9, 0x8000c, 0x8008c, 0x8004c, 0x900f9,
0x70101, 0x80052, 0x80012, 0x8011a, 0x70111, 0x80072, 0x80032, 0x900c5,
0x70109, 0x80062, 0x80022, 0x900a5, 0x80002, 0x80082, 0x80042, 0x900e5,
0x70105, 0x8005a, 0x8001a, 0x90095, 0x70115, 0x8007a, 0x8003a, 0x900d5,
0x7010d, 0x8006a, 0x8002a, 0x900b5, 0x8000a, 0x8008a, 0x8004a, 0x900f5,
0x70103, 0x80056, 0x80016, 0x8011e, 0x70113, 0x80076, 0x80036, 0x900cd,
0x7010b, 0x80066, 0x80026, 0x900ad, 0x80006, 0x80086, 0x80046, 0x900ed,
0x70107, 0x8005e, 0x8001e, 0x9009d, 0x70117, 0x8007e, 0x8003e, 0x900dd,
0x7010f, 0x8006e, 0x8002e, 0x900bd, 0x8000e, 0x8008e, 0x8004e, 0x900fd,
0x70100, 0x80051, 0x80011, 0x80119, 0x70110, 0x80071, 0x80031, 0x900c3,
0x70108, 0x80061, 0x80021, 0x900a3, 0x80001, 0x80081, 0x80041, 0x900e3,
0x70104, 0x80059, 0x80019, 0x90093, 0x70114, 0x80079, 0x80039, 0x900d3,
0x7010c, 0x80069, 0x80029, 0x900b3, 0x80009, 0x80089, 0x80049, 0x900f3,
0x70102, 0x80055, 0x80015, 0x8011d, 0x70112, 0x80075, 0x80035, 0x900cb,
0x7010a, 0x80065, 0x80025, 0x900ab, 0x80005, 0x80085, 0x80045, 0x900eb,
0x70106, 0x8005d, 0x8001d, 0x9009b, 0x70116, 0x8007d, 0x8003d, 0x900db,
0x7010e, 0x8006d, 0x8002d, 0x900bb, 0x8000d, 0x8008d, 0x8004d, 0x900fb,
0x70101, 0x80053, 0x80013, 0x8011b, 0x70111, 0x80073, 0x80033, 0x900c7,
0x70109, 0x80063, 0x80023, 0x900a7, 0x80003, 0x80083, 0x80043, 0x900e7,
0x70105, 0x8005b, 0x8001b, 0x90097, 0x70115, 0x8007b, 0x8003b, 0x900d7,
0x7010d, 0x8006b, 0x8002b, 0x900b7, 0x8000b, 0x8008b, 0x8004b, 0x900f7,
0x70103, 0x80057, 0x80017, 0x8011f, 0x70113, 0x80077, 0x80037, 0x900cf,
0x7010b, 0x80067, 0x80027, 0x900af, 0x80007, 0x80087, 0x80047, 0x900ef,
0x70107, 0x8005f, 0x8001f, 0x9009f, 0x70117, 0x8007f, 0x8003f, 0x900df,
0x7010f, 0x8006f, 0x8002f, 0x900bf, 0x8000f, 0x8008f, 0x8004f, 0x900ff
]), 9];
var fixedDistCodeTab = [new Uint32Array([
0x50000, 0x50010, 0x50008, 0x50018, 0x50004, 0x50014, 0x5000c, 0x5001c,
0x50002, 0x50012, 0x5000a, 0x5001a, 0x50006, 0x50016, 0x5000e, 0x00000,
0x50001, 0x50011, 0x50009, 0x50019, 0x50005, 0x50015, 0x5000d, 0x5001d,
0x50003, 0x50013, 0x5000b, 0x5001b, 0x50007, 0x50017, 0x5000f, 0x00000
]), 5];
function FlateStream(stream) {
var bytes = stream.getBytes();
var bytesPos = 0;
this.dict = stream.dict;
var cmf = bytes[bytesPos++];
var flg = bytes[bytesPos++];
if (cmf == -1 || flg == -1)
error('Invalid header in flate stream: ' + cmf + ', ' + flg);
if ((cmf & 0x0f) != 0x08)
error('Unknown compression method in flate stream: ' + cmf + ', ' + flg);
if ((((cmf << 8) + flg) % 31) != 0)
error('Bad FCHECK in flate stream: ' + cmf + ', ' + flg);
if (flg & 0x20)
error('FDICT bit set in flate stream: ' + cmf + ', ' + flg);
this.bytes = bytes;
this.bytesPos = bytesPos;
this.codeSize = 0;
this.codeBuf = 0;
DecodeStream.call(this);
}
FlateStream.prototype = Object.create(DecodeStream.prototype);
FlateStream.prototype.getBits = function flateStreamGetBits(bits) {
var codeSize = this.codeSize;
var codeBuf = this.codeBuf;
var bytes = this.bytes;
var bytesPos = this.bytesPos;
var b;
while (codeSize < bits) {
if (typeof (b = bytes[bytesPos++]) == 'undefined')
error('Bad encoding in flate stream');
codeBuf |= b << codeSize;
codeSize += 8;
}
b = codeBuf & ((1 << bits) - 1);
this.codeBuf = codeBuf >> bits;
this.codeSize = codeSize -= bits;
this.bytesPos = bytesPos;
return b;
};
FlateStream.prototype.getCode = function flateStreamGetCode(table) {
var codes = table[0];
var maxLen = table[1];
var codeSize = this.codeSize;
var codeBuf = this.codeBuf;
var bytes = this.bytes;
var bytesPos = this.bytesPos;
while (codeSize < maxLen) {
var b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
error('Bad encoding in flate stream');
codeBuf |= (b << codeSize);
codeSize += 8;
}
var code = codes[codeBuf & ((1 << maxLen) - 1)];
var codeLen = code >> 16;
var codeVal = code & 0xffff;
if (codeSize == 0 || codeSize < codeLen || codeLen == 0)
error('Bad encoding in flate stream');
this.codeBuf = (codeBuf >> codeLen);
this.codeSize = (codeSize - codeLen);
this.bytesPos = bytesPos;
return codeVal;
};
FlateStream.prototype.generateHuffmanTable =
function flateStreamGenerateHuffmanTable(lengths) {
var n = lengths.length;
// find max code length
var maxLen = 0;
for (var i = 0; i < n; ++i) {
if (lengths[i] > maxLen)
maxLen = lengths[i];
}
// build the table
var size = 1 << maxLen;
var codes = new Uint32Array(size);
for (var len = 1, code = 0, skip = 2;
len <= maxLen;
++len, code <<= 1, skip <<= 1) {
for (var val = 0; val < n; ++val) {
if (lengths[val] == len) {
// bit-reverse the code
var code2 = 0;
var t = code;
for (var i = 0; i < len; ++i) {
code2 = (code2 << 1) | (t & 1);
t >>= 1;
}
// fill the table entries
for (var i = code2; i < size; i += skip)
codes[i] = (len << 16) | val;
++code;
}
}
}
return [codes, maxLen];
};
FlateStream.prototype.readBlock = function flateStreamReadBlock() {
// read block header
var hdr = this.getBits(3);
if (hdr & 1)
this.eof = true;
hdr >>= 1;
if (hdr == 0) { // uncompressed block
var bytes = this.bytes;
var bytesPos = this.bytesPos;
var b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
error('Bad block header in flate stream');
var blockLen = b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
error('Bad block header in flate stream');
blockLen |= (b << 8);
if (typeof (b = bytes[bytesPos++]) == 'undefined')
error('Bad block header in flate stream');
var check = b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
error('Bad block header in flate stream');
check |= (b << 8);
if (check != (~blockLen & 0xffff))
error('Bad uncompressed block length in flate stream');
this.codeBuf = 0;
this.codeSize = 0;
var bufferLength = this.bufferLength;
var buffer = this.ensureBuffer(bufferLength + blockLen);
var end = bufferLength + blockLen;
this.bufferLength = end;
for (var n = bufferLength; n < end; ++n) {
if (typeof (b = bytes[bytesPos++]) == 'undefined') {
this.eof = true;
break;
}
buffer[n] = b;
}
this.bytesPos = bytesPos;
return;
}
var litCodeTable;
var distCodeTable;
if (hdr == 1) { // compressed block, fixed codes
litCodeTable = fixedLitCodeTab;
distCodeTable = fixedDistCodeTab;
} else if (hdr == 2) { // compressed block, dynamic codes
var numLitCodes = this.getBits(5) + 257;
var numDistCodes = this.getBits(5) + 1;
var numCodeLenCodes = this.getBits(4) + 4;
// build the code lengths code table
var codeLenCodeLengths = new Uint8Array(codeLenCodeMap.length);
for (var i = 0; i < numCodeLenCodes; ++i)
codeLenCodeLengths[codeLenCodeMap[i]] = this.getBits(3);
var codeLenCodeTab = this.generateHuffmanTable(codeLenCodeLengths);
// build the literal and distance code tables
var len = 0;
var i = 0;
var codes = numLitCodes + numDistCodes;
var codeLengths = new Uint8Array(codes);
while (i < codes) {
var code = this.getCode(codeLenCodeTab);
if (code == 16) {
var bitsLength = 2, bitsOffset = 3, what = len;
} else if (code == 17) {
var bitsLength = 3, bitsOffset = 3, what = (len = 0);
} else if (code == 18) {
var bitsLength = 7, bitsOffset = 11, what = (len = 0);
} else {
codeLengths[i++] = len = code;
continue;
}
var repeatLength = this.getBits(bitsLength) + bitsOffset;
while (repeatLength-- > 0)
codeLengths[i++] = what;
}
litCodeTable =
this.generateHuffmanTable(codeLengths.subarray(0, numLitCodes));
distCodeTable =
this.generateHuffmanTable(codeLengths.subarray(numLitCodes, codes));
} else {
error('Unknown block type in flate stream');
}
var buffer = this.buffer;
var limit = buffer ? buffer.length : 0;
var pos = this.bufferLength;
while (true) {
var code1 = this.getCode(litCodeTable);
if (code1 < 256) {
if (pos + 1 >= limit) {
buffer = this.ensureBuffer(pos + 1);
limit = buffer.length;
}
buffer[pos++] = code1;
continue;
}
if (code1 == 256) {
this.bufferLength = pos;
return;
}
code1 -= 257;
code1 = lengthDecode[code1];
var code2 = code1 >> 16;
if (code2 > 0)
code2 = this.getBits(code2);
var len = (code1 & 0xffff) + code2;
code1 = this.getCode(distCodeTable);
code1 = distDecode[code1];
code2 = code1 >> 16;
if (code2 > 0)
code2 = this.getBits(code2);
var dist = (code1 & 0xffff) + code2;
if (pos + len >= limit) {
buffer = this.ensureBuffer(pos + len);
limit = buffer.length;
}
for (var k = 0; k < len; ++k, ++pos)
buffer[pos] = buffer[pos - dist];
}
};
return FlateStream;
})();
var PredictorStream = (function PredictorStreamClosure() {
function PredictorStream(stream, params) {
var predictor = this.predictor = params.get('Predictor') || 1;
if (predictor <= 1)
return stream; // no prediction
if (predictor !== 2 && (predictor < 10 || predictor > 15))
error('Unsupported predictor: ' + predictor);
if (predictor === 2)
this.readBlock = this.readBlockTiff;
else
this.readBlock = this.readBlockPng;
this.stream = stream;
this.dict = stream.dict;
var colors = this.colors = params.get('Colors') || 1;
var bits = this.bits = params.get('BitsPerComponent') || 8;
var columns = this.columns = params.get('Columns') || 1;
this.pixBytes = (colors * bits + 7) >> 3;
this.rowBytes = (columns * colors * bits + 7) >> 3;
DecodeStream.call(this);
return this;
}
PredictorStream.prototype = Object.create(DecodeStream.prototype);
PredictorStream.prototype.readBlockTiff =
function predictorStreamReadBlockTiff() {
var rowBytes = this.rowBytes;
var bufferLength = this.bufferLength;
var buffer = this.ensureBuffer(bufferLength + rowBytes);
var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
var bits = this.bits;
var colors = this.colors;
var rawBytes = this.stream.getBytes(rowBytes);
var inbuf = 0, outbuf = 0;
var inbits = 0, outbits = 0;
if (bits === 1) {
for (var i = 0; i < rowBytes; ++i) {
var c = rawBytes[i];
inbuf = (inbuf << 8) | c;
// bitwise addition is exclusive or
// first shift inbuf and then add
currentRow[i] = (c ^ (inbuf >> colors)) & 0xFF;
// truncate inbuf (assumes colors < 16)
inbuf &= 0xFFFF;
}
} else if (bits === 8) {
for (var i = 0; i < colors; ++i)
currentRow[i] = rawBytes[i];
for (; i < rowBytes; ++i)
currentRow[i] = currentRow[i - colors] + rawBytes[i];
} else {
var compArray = new Uint8Array(colors + 1);
var bitMask = (1 << bits) - 1;
var j = 0, k = 0;
var columns = this.columns;
for (var i = 0; i < columns; ++i) {
for (var kk = 0; kk < colors; ++kk) {
if (inbits < bits) {
inbuf = (inbuf << 8) | (rawBytes[j++] & 0xFF);
inbits += 8;
}
compArray[kk] = (compArray[kk] +
(inbuf >> (inbits - bits))) & bitMask;
inbits -= bits;
outbuf = (outbuf << bits) | compArray[kk];
outbits += bits;
if (outbits >= 8) {
currentRow[k++] = (outbuf >> (outbits - 8)) & 0xFF;
outbits -= 8;
}
}
}
if (outbits > 0) {
currentRow[k++] = (outbuf << (8 - outbits)) +
(inbuf & ((1 << (8 - outbits)) - 1));
}
}
this.bufferLength += rowBytes;
};
PredictorStream.prototype.readBlockPng =
function predictorStreamReadBlockPng() {
var rowBytes = this.rowBytes;
var pixBytes = this.pixBytes;
var predictor = this.stream.getByte();
var rawBytes = this.stream.getBytes(rowBytes);
var bufferLength = this.bufferLength;
var buffer = this.ensureBuffer(bufferLength + rowBytes);
var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
if (prevRow.length == 0)
prevRow = new Uint8Array(rowBytes);
switch (predictor) {
case 0:
for (var i = 0; i < rowBytes; ++i)
currentRow[i] = rawBytes[i];
break;
case 1:
for (var i = 0; i < pixBytes; ++i)
currentRow[i] = rawBytes[i];
for (; i < rowBytes; ++i)
currentRow[i] = (currentRow[i - pixBytes] + rawBytes[i]) & 0xFF;
break;
case 2:
for (var i = 0; i < rowBytes; ++i)
currentRow[i] = (prevRow[i] + rawBytes[i]) & 0xFF;
break;
case 3:
for (var i = 0; i < pixBytes; ++i)
currentRow[i] = (prevRow[i] >> 1) + rawBytes[i];
for (; i < rowBytes; ++i) {
currentRow[i] = (((prevRow[i] + currentRow[i - pixBytes]) >> 1) +
rawBytes[i]) & 0xFF;
}
break;
case 4:
// we need to save the up left pixels values. the simplest way
// is to create a new buffer
for (var i = 0; i < pixBytes; ++i) {
var up = prevRow[i];
var c = rawBytes[i];
currentRow[i] = up + c;
}
for (; i < rowBytes; ++i) {
var up = prevRow[i];
var upLeft = prevRow[i - pixBytes];
var left = currentRow[i - pixBytes];
var p = left + up - upLeft;
var pa = p - left;
if (pa < 0)
pa = -pa;
var pb = p - up;
if (pb < 0)
pb = -pb;
var pc = p - upLeft;
if (pc < 0)
pc = -pc;
var c = rawBytes[i];
if (pa <= pb && pa <= pc)
currentRow[i] = left + c;
else if (pb <= pc)
currentRow[i] = up + c;
else
currentRow[i] = upLeft + c;
}
break;
default:
error('Unsupported predictor: ' + predictor);
}
this.bufferLength += rowBytes;
};
return PredictorStream;
})();
/**
* Depending on the type of JPEG a JpegStream is handled in different ways. For
* JPEG's that are supported natively such as DeviceGray and DeviceRGB the image
* data is stored and then loaded by the browser. For unsupported JPEG's we use
* a library to decode these images and the stream behaves like all the other
* DecodeStreams.
*/
var JpegStream = (function JpegStreamClosure() {
function isAdobeImage(bytes) {
var maxBytesScanned = Math.max(bytes.length - 16, 1024);
// Looking for APP14, 'Adobe'
for (var i = 0; i < maxBytesScanned; ++i) {
if (bytes[i] == 0xFF && bytes[i + 1] == 0xEE &&
bytes[i + 2] == 0x00 && bytes[i + 3] == 0x0E &&
bytes[i + 4] == 0x41 && bytes[i + 5] == 0x64 &&
bytes[i + 6] == 0x6F && bytes[i + 7] == 0x62 &&
bytes[i + 8] == 0x65 && bytes[i + 9] == 0x00)
return true;
// scanning until frame tag
if (bytes[i] == 0xFF && bytes[i + 1] == 0xC0)
break;
}
return false;
}
function fixAdobeImage(bytes) {
// Inserting 'EMBED' marker after JPEG signature
var embedMarker = new Uint8Array([0xFF, 0xEC, 0, 8, 0x45, 0x4D, 0x42, 0x45,
0x44, 0]);
var newBytes = new Uint8Array(bytes.length + embedMarker.length);
newBytes.set(bytes, embedMarker.length);
// copy JPEG header
newBytes[0] = bytes[0];
newBytes[1] = bytes[1];
newBytes.set(embedMarker, 2);
return newBytes;
}
function JpegStream(bytes, dict, xref) {
// TODO: per poppler, some images may have 'junk' before that
// need to be removed
this.dict = dict;
// Flag indicating wether the image can be natively loaded.
this.isNative = true;
this.colorTransform = -1;
if (isAdobeImage(bytes)) {
// when bug 674619 land, let's check if browser can do
// normal cmyk and then we won't have to the following
var cs = xref.fetchIfRef(dict.get('ColorSpace'));
// DeviceRGB and DeviceGray are the only Adobe images that work natively
if (isName(cs) && (cs.name === 'DeviceRGB' || cs.name === 'DeviceGray')) {
bytes = fixAdobeImage(bytes);
this.src = bytesToString(bytes);
} else {
this.colorTransform = dict.get('ColorTransform');
this.isNative = false;
this.bytes = bytes;
}
} else {
this.src = bytesToString(bytes);
}
DecodeStream.call(this);
}
JpegStream.prototype = Object.create(DecodeStream.prototype);
JpegStream.prototype.ensureBuffer = function jpegStreamEnsureBuffer(req) {
if (this.bufferLength)
return;
var jpegImage = new JpegImage();
jpegImage.colorTransform = this.colorTransform;
jpegImage.parse(this.bytes);
var width = jpegImage.width;
var height = jpegImage.height;
var data = jpegImage.getData(width, height);
this.buffer = data;
this.bufferLength = data.length;
};
JpegStream.prototype.getIR = function jpegStreamGetIR() {
return this.src;
};
JpegStream.prototype.getChar = function jpegStreamGetChar() {
error('internal error: getChar is not valid on JpegStream');
};
return JpegStream;
})();
var DecryptStream = (function DecryptStreamClosure() {
function DecryptStream(str, decrypt) {
this.str = str;
this.dict = str.dict;
this.decrypt = decrypt;
DecodeStream.call(this);
}
var chunkSize = 512;
DecryptStream.prototype = Object.create(DecodeStream.prototype);
DecryptStream.prototype.readBlock = function decryptStreamReadBlock() {
var chunk = this.str.getBytes(chunkSize);
if (!chunk || chunk.length == 0) {
this.eof = true;
return;
}
var decrypt = this.decrypt;
chunk = decrypt(chunk);
var bufferLength = this.bufferLength;
var i, n = chunk.length;
var buffer = this.ensureBuffer(bufferLength + n);
for (i = 0; i < n; i++)
buffer[bufferLength++] = chunk[i];
this.bufferLength = bufferLength;
};
return DecryptStream;
})();
var Ascii85Stream = (function Ascii85StreamClosure() {
function Ascii85Stream(str) {
this.str = str;
this.dict = str.dict;
this.input = new Uint8Array(5);
DecodeStream.call(this);
}
Ascii85Stream.prototype = Object.create(DecodeStream.prototype);
Ascii85Stream.prototype.readBlock = function ascii85StreamReadBlock() {
var tildaCode = '~'.charCodeAt(0);
var zCode = 'z'.charCodeAt(0);
var str = this.str;
var c = str.getByte();
while (Lexer.isSpace(String.fromCharCode(c)))
c = str.getByte();
if (!c || c === tildaCode) {
this.eof = true;
return;
}
var bufferLength = this.bufferLength, buffer;
// special code for z
if (c == zCode) {
buffer = this.ensureBuffer(bufferLength + 4);
for (var i = 0; i < 4; ++i)
buffer[bufferLength + i] = 0;
this.bufferLength += 4;
} else {
var input = this.input;
input[0] = c;
for (var i = 1; i < 5; ++i) {
c = str.getByte();
while (Lexer.isSpace(String.fromCharCode(c)))
c = str.getByte();
input[i] = c;
if (!c || c == tildaCode)
break;
}
buffer = this.ensureBuffer(bufferLength + i - 1);
this.bufferLength += i - 1;
// partial ending;
if (i < 5) {
for (; i < 5; ++i)
input[i] = 0x21 + 84;
this.eof = true;
}
var t = 0;
for (var i = 0; i < 5; ++i)
t = t * 85 + (input[i] - 0x21);
for (var i = 3; i >= 0; --i) {
buffer[bufferLength + i] = t & 0xFF;
t >>= 8;
}
}
};
return Ascii85Stream;
})();
var AsciiHexStream = (function AsciiHexStreamClosure() {
function AsciiHexStream(str) {
this.str = str;
this.dict = str.dict;
DecodeStream.call(this);
}
var hexvalueMap = {
9: -1, // \t
32: -1, // space
48: 0,
49: 1,
50: 2,
51: 3,
52: 4,
53: 5,
54: 6,
55: 7,
56: 8,
57: 9,
65: 10,
66: 11,
67: 12,
68: 13,
69: 14,
70: 15,
97: 10,
98: 11,
99: 12,
100: 13,
101: 14,
102: 15
};
AsciiHexStream.prototype = Object.create(DecodeStream.prototype);
AsciiHexStream.prototype.readBlock = function asciiHexStreamReadBlock() {
var gtCode = '>'.charCodeAt(0), bytes = this.str.getBytes(), c, n,
decodeLength, buffer, bufferLength, i, length;
decodeLength = (bytes.length + 1) >> 1;
buffer = this.ensureBuffer(this.bufferLength + decodeLength);
bufferLength = this.bufferLength;
for (i = 0, length = bytes.length; i < length; i++) {
c = hexvalueMap[bytes[i]];
while (c == -1 && (i + 1) < length) {
c = hexvalueMap[bytes[++i]];
}
if ((i + 1) < length && (bytes[i + 1] !== gtCode)) {
n = hexvalueMap[bytes[++i]];
buffer[bufferLength++] = c * 16 + n;
} else {
// EOD marker at an odd number, behave as if a 0 followed the last
// digit.
if (bytes[i] !== gtCode) {
buffer[bufferLength++] = c * 16;
}
}
}
this.bufferLength = bufferLength;
this.eof = true;
};
return AsciiHexStream;
})();
var CCITTFaxStream = (function CCITTFaxStreamClosure() {
var ccittEOL = -2;
var twoDimPass = 0;
var twoDimHoriz = 1;
var twoDimVert0 = 2;
var twoDimVertR1 = 3;
var twoDimVertL1 = 4;
var twoDimVertR2 = 5;
var twoDimVertL2 = 6;
var twoDimVertR3 = 7;
var twoDimVertL3 = 8;
var twoDimTable = [
[-1, -1], [-1, -1], // 000000x
[7, twoDimVertL3], // 0000010
[7, twoDimVertR3], // 0000011
[6, twoDimVertL2], [6, twoDimVertL2], // 000010x
[6, twoDimVertR2], [6, twoDimVertR2], // 000011x
[4, twoDimPass], [4, twoDimPass], // 0001xxx
[4, twoDimPass], [4, twoDimPass],
[4, twoDimPass], [4, twoDimPass],
[4, twoDimPass], [4, twoDimPass],
[3, twoDimHoriz], [3, twoDimHoriz], // 001xxxx
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimHoriz], [3, twoDimHoriz],
[3, twoDimVertL1], [3, twoDimVertL1], // 010xxxx
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertL1], [3, twoDimVertL1],
[3, twoDimVertR1], [3, twoDimVertR1], // 011xxxx
[3, twoDimVertR1], [3, twoDimVertR1],
[3, twoDimVertR1], [3, twoDimVertR1],
[3, twoDimVertR1], [3, twoDimVertR1],
[3, twoDimVertR1], [3, twoDimVertR1],
[3, twoDimVertR1], [3, twoDimVertR1],
[3, twoDimVertR1], [3, twoDimVertR1],
[3, twoDimVertR1], [3, twoDimVertR1],
[1, twoDimVert0], [1, twoDimVert0], // 1xxxxxx
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0],
[1, twoDimVert0], [1, twoDimVert0]
];
var whiteTable1 = [
[-1, -1], // 00000
[12, ccittEOL], // 00001
[-1, -1], [-1, -1], // 0001x
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 001xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 010xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 011xx
[11, 1792], [11, 1792], // 1000x
[12, 1984], // 10010
[12, 2048], // 10011
[12, 2112], // 10100
[12, 2176], // 10101
[12, 2240], // 10110
[12, 2304], // 10111
[11, 1856], [11, 1856], // 1100x
[11, 1920], [11, 1920], // 1101x
[12, 2368], // 11100
[12, 2432], // 11101
[12, 2496], // 11110
[12, 2560] // 11111
];
var whiteTable2 = [
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 0000000xx
[8, 29], [8, 29], // 00000010x
[8, 30], [8, 30], // 00000011x
[8, 45], [8, 45], // 00000100x
[8, 46], [8, 46], // 00000101x
[7, 22], [7, 22], [7, 22], [7, 22], // 0000011xx
[7, 23], [7, 23], [7, 23], [7, 23], // 0000100xx
[8, 47], [8, 47], // 00001010x
[8, 48], [8, 48], // 00001011x
[6, 13], [6, 13], [6, 13], [6, 13], // 000011xxx
[6, 13], [6, 13], [6, 13], [6, 13],
[7, 20], [7, 20], [7, 20], [7, 20], // 0001000xx
[8, 33], [8, 33], // 00010010x
[8, 34], [8, 34], // 00010011x
[8, 35], [8, 35], // 00010100x
[8, 36], [8, 36], // 00010101x
[8, 37], [8, 37], // 00010110x
[8, 38], [8, 38], // 00010111x
[7, 19], [7, 19], [7, 19], [7, 19], // 0001100xx
[8, 31], [8, 31], // 00011010x
[8, 32], [8, 32], // 00011011x
[6, 1], [6, 1], [6, 1], [6, 1], // 000111xxx
[6, 1], [6, 1], [6, 1], [6, 1],
[6, 12], [6, 12], [6, 12], [6, 12], // 001000xxx
[6, 12], [6, 12], [6, 12], [6, 12],
[8, 53], [8, 53], // 00100100x
[8, 54], [8, 54], // 00100101x
[7, 26], [7, 26], [7, 26], [7, 26], // 0010011xx
[8, 39], [8, 39], // 00101000x
[8, 40], [8, 40], // 00101001x
[8, 41], [8, 41], // 00101010x
[8, 42], [8, 42], // 00101011x
[8, 43], [8, 43], // 00101100x
[8, 44], [8, 44], // 00101101x
[7, 21], [7, 21], [7, 21], [7, 21], // 0010111xx
[7, 28], [7, 28], [7, 28], [7, 28], // 0011000xx
[8, 61], [8, 61], // 00110010x
[8, 62], [8, 62], // 00110011x
[8, 63], [8, 63], // 00110100x
[8, 0], [8, 0], // 00110101x
[8, 320], [8, 320], // 00110110x
[8, 384], [8, 384], // 00110111x
[5, 10], [5, 10], [5, 10], [5, 10], // 00111xxxx
[5, 10], [5, 10], [5, 10], [5, 10],
[5, 10], [5, 10], [5, 10], [5, 10],
[5, 10], [5, 10], [5, 10], [5, 10],
[5, 11], [5, 11], [5, 11], [5, 11], // 01000xxxx
[5, 11], [5, 11], [5, 11], [5, 11],
[5, 11], [5, 11], [5, 11], [5, 11],
[5, 11], [5, 11], [5, 11], [5, 11],
[7, 27], [7, 27], [7, 27], [7, 27], // 0100100xx
[8, 59], [8, 59], // 01001010x
[8, 60], [8, 60], // 01001011x
[9, 1472], // 010011000
[9, 1536], // 010011001
[9, 1600], // 010011010
[9, 1728], // 010011011
[7, 18], [7, 18], [7, 18], [7, 18], // 0100111xx
[7, 24], [7, 24], [7, 24], [7, 24], // 0101000xx
[8, 49], [8, 49], // 01010010x
[8, 50], [8, 50], // 01010011x
[8, 51], [8, 51], // 01010100x
[8, 52], [8, 52], // 01010101x
[7, 25], [7, 25], [7, 25], [7, 25], // 0101011xx
[8, 55], [8, 55], // 01011000x
[8, 56], [8, 56], // 01011001x
[8, 57], [8, 57], // 01011010x
[8, 58], [8, 58], // 01011011x
[6, 192], [6, 192], [6, 192], [6, 192], // 010111xxx
[6, 192], [6, 192], [6, 192], [6, 192],
[6, 1664], [6, 1664], [6, 1664], [6, 1664], // 011000xxx
[6, 1664], [6, 1664], [6, 1664], [6, 1664],
[8, 448], [8, 448], // 01100100x
[8, 512], [8, 512], // 01100101x
[9, 704], // 011001100
[9, 768], // 011001101
[8, 640], [8, 640], // 01100111x
[8, 576], [8, 576], // 01101000x
[9, 832], // 011010010
[9, 896], // 011010011
[9, 960], // 011010100
[9, 1024], // 011010101
[9, 1088], // 011010110
[9, 1152], // 011010111
[9, 1216], // 011011000
[9, 1280], // 011011001
[9, 1344], // 011011010
[9, 1408], // 011011011
[7, 256], [7, 256], [7, 256], [7, 256], // 0110111xx
[4, 2], [4, 2], [4, 2], [4, 2], // 0111xxxxx
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 2], [4, 2], [4, 2], [4, 2],
[4, 3], [4, 3], [4, 3], [4, 3], // 1000xxxxx
[4, 3], [4, 3], [4, 3], [4, 3],
[4, 3], [4, 3], [4, 3], [4, 3],
[4, 3], [4, 3], [4, 3], [4, 3],
[4, 3], [4, 3], [4, 3], [4, 3],
[4, 3], [4, 3], [4, 3], [4, 3],
[4, 3], [4, 3], [4, 3], [4, 3],
[4, 3], [4, 3], [4, 3], [4, 3],
[5, 128], [5, 128], [5, 128], [5, 128], // 10010xxxx
[5, 128], [5, 128], [5, 128], [5, 128],
[5, 128], [5, 128], [5, 128], [5, 128],
[5, 128], [5, 128], [5, 128], [5, 128],
[5, 8], [5, 8], [5, 8], [5, 8], // 10011xxxx
[5, 8], [5, 8], [5, 8], [5, 8],
[5, 8], [5, 8], [5, 8], [5, 8],
[5, 8], [5, 8], [5, 8], [5, 8],
[5, 9], [5, 9], [5, 9], [5, 9], // 10100xxxx
[5, 9], [5, 9], [5, 9], [5, 9],
[5, 9], [5, 9], [5, 9], [5, 9],
[5, 9], [5, 9], [5, 9], [5, 9],
[6, 16], [6, 16], [6, 16], [6, 16], // 101010xxx
[6, 16], [6, 16], [6, 16], [6, 16],
[6, 17], [6, 17], [6, 17], [6, 17], // 101011xxx
[6, 17], [6, 17], [6, 17], [6, 17],
[4, 4], [4, 4], [4, 4], [4, 4], // 1011xxxxx
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 4], [4, 4], [4, 4], [4, 4],
[4, 5], [4, 5], [4, 5], [4, 5], // 1100xxxxx
[4, 5], [4, 5], [4, 5], [4, 5],
[4, 5], [4, 5], [4, 5], [4, 5],
[4, 5], [4, 5], [4, 5], [4, 5],
[4, 5], [4, 5], [4, 5], [4, 5],
[4, 5], [4, 5], [4, 5], [4, 5],
[4, 5], [4, 5], [4, 5], [4, 5],
[4, 5], [4, 5], [4, 5], [4, 5],
[6, 14], [6, 14], [6, 14], [6, 14], // 110100xxx
[6, 14], [6, 14], [6, 14], [6, 14],
[6, 15], [6, 15], [6, 15], [6, 15], // 110101xxx
[6, 15], [6, 15], [6, 15], [6, 15],
[5, 64], [5, 64], [5, 64], [5, 64], // 11011xxxx
[5, 64], [5, 64], [5, 64], [5, 64],
[5, 64], [5, 64], [5, 64], [5, 64],
[5, 64], [5, 64], [5, 64], [5, 64],
[4, 6], [4, 6], [4, 6], [4, 6], // 1110xxxxx
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 6], [4, 6], [4, 6], [4, 6],
[4, 7], [4, 7], [4, 7], [4, 7], // 1111xxxxx
[4, 7], [4, 7], [4, 7], [4, 7],
[4, 7], [4, 7], [4, 7], [4, 7],
[4, 7], [4, 7], [4, 7], [4, 7],
[4, 7], [4, 7], [4, 7], [4, 7],
[4, 7], [4, 7], [4, 7], [4, 7],
[4, 7], [4, 7], [4, 7], [4, 7],
[4, 7], [4, 7], [4, 7], [4, 7]
];
var blackTable1 = [
[-1, -1], [-1, -1], // 000000000000x
[12, ccittEOL], [12, ccittEOL], // 000000000001x
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000001xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000010xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000011xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000100xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000101xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000110xx
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 00000000111xx
[11, 1792], [11, 1792], [11, 1792], [11, 1792], // 00000001000xx
[12, 1984], [12, 1984], // 000000010010x
[12, 2048], [12, 2048], // 000000010011x
[12, 2112], [12, 2112], // 000000010100x
[12, 2176], [12, 2176], // 000000010101x
[12, 2240], [12, 2240], // 000000010110x
[12, 2304], [12, 2304], // 000000010111x
[11, 1856], [11, 1856], [11, 1856], [11, 1856], // 00000001100xx
[11, 1920], [11, 1920], [11, 1920], [11, 1920], // 00000001101xx
[12, 2368], [12, 2368], // 000000011100x
[12, 2432], [12, 2432], // 000000011101x
[12, 2496], [12, 2496], // 000000011110x
[12, 2560], [12, 2560], // 000000011111x
[10, 18], [10, 18], [10, 18], [10, 18], // 0000001000xxx
[10, 18], [10, 18], [10, 18], [10, 18],
[12, 52], [12, 52], // 000000100100x
[13, 640], // 0000001001010
[13, 704], // 0000001001011
[13, 768], // 0000001001100
[13, 832], // 0000001001101
[12, 55], [12, 55], // 000000100111x
[12, 56], [12, 56], // 000000101000x
[13, 1280], // 0000001010010
[13, 1344], // 0000001010011
[13, 1408], // 0000001010100
[13, 1472], // 0000001010101
[12, 59], [12, 59], // 000000101011x
[12, 60], [12, 60], // 000000101100x
[13, 1536], // 0000001011010
[13, 1600], // 0000001011011
[11, 24], [11, 24], [11, 24], [11, 24], // 00000010111xx
[11, 25], [11, 25], [11, 25], [11, 25], // 00000011000xx
[13, 1664], // 0000001100100
[13, 1728], // 0000001100101
[12, 320], [12, 320], // 000000110011x
[12, 384], [12, 384], // 000000110100x
[12, 448], [12, 448], // 000000110101x
[13, 512], // 0000001101100
[13, 576], // 0000001101101
[12, 53], [12, 53], // 000000110111x
[12, 54], [12, 54], // 000000111000x
[13, 896], // 0000001110010
[13, 960], // 0000001110011
[13, 1024], // 0000001110100
[13, 1088], // 0000001110101
[13, 1152], // 0000001110110
[13, 1216], // 0000001110111
[10, 64], [10, 64], [10, 64], [10, 64], // 0000001111xxx
[10, 64], [10, 64], [10, 64], [10, 64]
];
var blackTable2 = [
[8, 13], [8, 13], [8, 13], [8, 13], // 00000100xxxx
[8, 13], [8, 13], [8, 13], [8, 13],
[8, 13], [8, 13], [8, 13], [8, 13],
[8, 13], [8, 13], [8, 13], [8, 13],
[11, 23], [11, 23], // 00000101000x
[12, 50], // 000001010010
[12, 51], // 000001010011
[12, 44], // 000001010100
[12, 45], // 000001010101
[12, 46], // 000001010110
[12, 47], // 000001010111
[12, 57], // 000001011000
[12, 58], // 000001011001
[12, 61], // 000001011010
[12, 256], // 000001011011
[10, 16], [10, 16], [10, 16], [10, 16], // 0000010111xx
[10, 17], [10, 17], [10, 17], [10, 17], // 0000011000xx
[12, 48], // 000001100100
[12, 49], // 000001100101
[12, 62], // 000001100110
[12, 63], // 000001100111
[12, 30], // 000001101000
[12, 31], // 000001101001
[12, 32], // 000001101010
[12, 33], // 000001101011
[12, 40], // 000001101100
[12, 41], // 000001101101
[11, 22], [11, 22], // 00000110111x
[8, 14], [8, 14], [8, 14], [8, 14], // 00000111xxxx
[8, 14], [8, 14], [8, 14], [8, 14],
[8, 14], [8, 14], [8, 14], [8, 14],
[8, 14], [8, 14], [8, 14], [8, 14],
[7, 10], [7, 10], [7, 10], [7, 10], // 0000100xxxxx
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 10], [7, 10], [7, 10], [7, 10],
[7, 11], [7, 11], [7, 11], [7, 11], // 0000101xxxxx
[7, 11], [7, 11], [7, 11], [7, 11],
[7, 11], [7, 11], [7, 11], [7, 11],
[7, 11], [7, 11], [7, 11], [7, 11],
[7, 11], [7, 11], [7, 11], [7, 11],
[7, 11], [7, 11], [7, 11], [7, 11],
[7, 11], [7, 11], [7, 11], [7, 11],
[7, 11], [7, 11], [7, 11], [7, 11],
[9, 15], [9, 15], [9, 15], [9, 15], // 000011000xxx
[9, 15], [9, 15], [9, 15], [9, 15],
[12, 128], // 000011001000
[12, 192], // 000011001001
[12, 26], // 000011001010
[12, 27], // 000011001011
[12, 28], // 000011001100
[12, 29], // 000011001101
[11, 19], [11, 19], // 00001100111x
[11, 20], [11, 20], // 00001101000x
[12, 34], // 000011010010
[12, 35], // 000011010011
[12, 36], // 000011010100
[12, 37], // 000011010101
[12, 38], // 000011010110
[12, 39], // 000011010111
[11, 21], [11, 21], // 00001101100x
[12, 42], // 000011011010
[12, 43], // 000011011011
[10, 0], [10, 0], [10, 0], [10, 0], // 0000110111xx
[7, 12], [7, 12], [7, 12], [7, 12], // 0000111xxxxx
[7, 12], [7, 12], [7, 12], [7, 12],
[7, 12], [7, 12], [7, 12], [7, 12],
[7, 12], [7, 12], [7, 12], [7, 12],
[7, 12], [7, 12], [7, 12], [7, 12],
[7, 12], [7, 12], [7, 12], [7, 12],
[7, 12], [7, 12], [7, 12], [7, 12],
[7, 12], [7, 12], [7, 12], [7, 12]
];
var blackTable3 = [
[-1, -1], [-1, -1], [-1, -1], [-1, -1], // 0000xx
[6, 9], // 000100
[6, 8], // 000101
[5, 7], [5, 7], // 00011x
[4, 6], [4, 6], [4, 6], [4, 6], // 0010xx
[4, 5], [4, 5], [4, 5], [4, 5], // 0011xx
[3, 1], [3, 1], [3, 1], [3, 1], // 010xxx
[3, 1], [3, 1], [3, 1], [3, 1],
[3, 4], [3, 4], [3, 4], [3, 4], // 011xxx
[3, 4], [3, 4], [3, 4], [3, 4],
[2, 3], [2, 3], [2, 3], [2, 3], // 10xxxx
[2, 3], [2, 3], [2, 3], [2, 3],
[2, 3], [2, 3], [2, 3], [2, 3],
[2, 3], [2, 3], [2, 3], [2, 3],
[2, 2], [2, 2], [2, 2], [2, 2], // 11xxxx
[2, 2], [2, 2], [2, 2], [2, 2],
[2, 2], [2, 2], [2, 2], [2, 2],
[2, 2], [2, 2], [2, 2], [2, 2]
];
function CCITTFaxStream(str, params) {
this.str = str;
this.dict = str.dict;
params = params || new Dict();
this.encoding = params.get('K') || 0;
this.eoline = params.get('EndOfLine') || false;
this.byteAlign = params.get('EncodedByteAlign') || false;
this.columns = params.get('Columns') || 1728;
this.rows = params.get('Rows') || 0;
var eoblock = params.get('EndOfBlock');
if (eoblock == null)
eoblock = true;
this.eoblock = eoblock;
this.black = params.get('BlackIs1') || false;
this.codingLine = new Uint32Array(this.columns + 1);
this.refLine = new Uint32Array(this.columns + 2);
this.codingLine[0] = this.columns;
this.codingPos = 0;
this.row = 0;
this.nextLine2D = this.encoding < 0;
this.inputBits = 0;
this.inputBuf = 0;
this.outputBits = 0;
this.buf = EOF;
var code1;
while ((code1 = this.lookBits(12)) == 0) {
this.eatBits(1);
}
if (code1 == 1) {
this.eatBits(12);
}
if (this.encoding > 0) {
this.nextLine2D = !this.lookBits(1);
this.eatBits(1);
}
DecodeStream.call(this);
}
CCITTFaxStream.prototype = Object.create(DecodeStream.prototype);
CCITTFaxStream.prototype.readBlock = function ccittFaxStreamReadBlock() {
while (!this.eof) {
var c = this.lookChar();
this.buf = EOF;
this.ensureBuffer(this.bufferLength + 1);
this.buffer[this.bufferLength++] = c;
}
};
CCITTFaxStream.prototype.addPixels =
function ccittFaxStreamAddPixels(a1, blackPixels) {
var codingLine = this.codingLine;
var codingPos = this.codingPos;
if (a1 > codingLine[codingPos]) {
if (a1 > this.columns) {
warn('row is wrong length');
this.err = true;
a1 = this.columns;
}
if ((codingPos & 1) ^ blackPixels) {
++codingPos;
}
codingLine[codingPos] = a1;
}
this.codingPos = codingPos;
};
CCITTFaxStream.prototype.addPixelsNeg =
function ccittFaxStreamAddPixelsNeg(a1, blackPixels) {
var codingLine = this.codingLine;
var codingPos = this.codingPos;
if (a1 > codingLine[codingPos]) {
if (a1 > this.columns) {
warn('row is wrong length');
this.err = true;
a1 = this.columns;
}
if ((codingPos & 1) ^ blackPixels)
++codingPos;
codingLine[codingPos] = a1;
} else if (a1 < codingLine[codingPos]) {
if (a1 < 0) {
warn('invalid code');
this.err = true;
a1 = 0;
}
while (codingPos > 0 && a1 < codingLine[codingPos - 1])
--codingPos;
codingLine[codingPos] = a1;
}
this.codingPos = codingPos;
};
CCITTFaxStream.prototype.lookChar = function ccittFaxStreamLookChar() {
if (this.buf != EOF)
return this.buf;
var refLine = this.refLine;
var codingLine = this.codingLine;
var columns = this.columns;
var refPos, blackPixels, bits;
if (this.outputBits == 0) {
if (this.eof)
return null;
this.err = false;
var code1, code2, code3;
if (this.nextLine2D) {
for (var i = 0; codingLine[i] < columns; ++i)
refLine[i] = codingLine[i];
refLine[i++] = columns;
refLine[i] = columns;
codingLine[0] = 0;
this.codingPos = 0;
refPos = 0;
blackPixels = 0;
while (codingLine[this.codingPos] < columns) {
code1 = this.getTwoDimCode();
switch (code1) {
case twoDimPass:
this.addPixels(refLine[refPos + 1], blackPixels);
if (refLine[refPos + 1] < columns)
refPos += 2;
break;
case twoDimHoriz:
code1 = code2 = 0;
if (blackPixels) {
do {
code1 += (code3 = this.getBlackCode());
} while (code3 >= 64);
do {
code2 += (code3 = this.getWhiteCode());
} while (code3 >= 64);
} else {
do {
code1 += (code3 = this.getWhiteCode());
} while (code3 >= 64);
do {
code2 += (code3 = this.getBlackCode());
} while (code3 >= 64);
}
this.addPixels(codingLine[this.codingPos] +
code1, blackPixels);
if (codingLine[this.codingPos] < columns) {
this.addPixels(codingLine[this.codingPos] + code2,
blackPixels ^ 1);
}
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns) {
refPos += 2;
}
break;
case twoDimVertR3:
this.addPixels(refLine[refPos] + 3, blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns)
refPos += 2;
}
break;
case twoDimVertR2:
this.addPixels(refLine[refPos] + 2, blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns) {
refPos += 2;
}
}
break;
case twoDimVertR1:
this.addPixels(refLine[refPos] + 1, blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns)
refPos += 2;
}
break;
case twoDimVert0:
this.addPixels(refLine[refPos], blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns)
refPos += 2;
}
break;
case twoDimVertL3:
this.addPixelsNeg(refLine[refPos] - 3, blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
if (refPos > 0)
--refPos;
else
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns)
refPos += 2;
}
break;
case twoDimVertL2:
this.addPixelsNeg(refLine[refPos] - 2, blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
if (refPos > 0)
--refPos;
else
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns)
refPos += 2;
}
break;
case twoDimVertL1:
this.addPixelsNeg(refLine[refPos] - 1, blackPixels);
blackPixels ^= 1;
if (codingLine[this.codingPos] < columns) {
if (refPos > 0)
--refPos;
else
++refPos;
while (refLine[refPos] <= codingLine[this.codingPos] &&
refLine[refPos] < columns)
refPos += 2;
}
break;
case EOF:
this.addPixels(columns, 0);
this.eof = true;
break;
default:
warn('bad 2d code');
this.addPixels(columns, 0);
this.err = true;
}
}
} else {
codingLine[0] = 0;
this.codingPos = 0;
blackPixels = 0;
while (codingLine[this.codingPos] < columns) {
code1 = 0;
if (blackPixels) {
do {
code1 += (code3 = this.getBlackCode());
} while (code3 >= 64);
} else {
do {
code1 += (code3 = this.getWhiteCode());
} while (code3 >= 64);
}
this.addPixels(codingLine[this.codingPos] + code1, blackPixels);
blackPixels ^= 1;
}
}
if (this.byteAlign)
this.inputBits &= ~7;
var gotEOL = false;
if (!this.eoblock && this.row == this.rows - 1) {
this.eof = true;
} else {
code1 = this.lookBits(12);
while (code1 == 0) {
this.eatBits(1);
code1 = this.lookBits(12);
}
if (code1 == 1) {
this.eatBits(12);
gotEOL = true;
} else if (code1 == EOF) {
this.eof = true;
}
}
if (!this.eof && this.encoding > 0) {
this.nextLine2D = !this.lookBits(1);
this.eatBits(1);
}
if (this.eoblock && gotEOL) {
code1 = this.lookBits(12);
if (code1 == 1) {
this.eatBits(12);
if (this.encoding > 0) {
this.lookBits(1);
this.eatBits(1);
}
if (this.encoding >= 0) {
for (var i = 0; i < 4; ++i) {
code1 = this.lookBits(12);
if (code1 != 1)
warn('bad rtc code: ' + code1);
this.eatBits(12);
if (this.encoding > 0) {
this.lookBits(1);
this.eatBits(1);
}
}
}
this.eof = true;
}
} else if (this.err && this.eoline) {
while (true) {
code1 = this.lookBits(13);
if (code1 == EOF) {
this.eof = true;
return null;
}
if ((code1 >> 1) == 1) {
break;
}
this.eatBits(1);
}
this.eatBits(12);
if (this.encoding > 0) {
this.eatBits(1);
this.nextLine2D = !(code1 & 1);
}
}
if (codingLine[0] > 0)
this.outputBits = codingLine[this.codingPos = 0];
else
this.outputBits = codingLine[this.codingPos = 1];
this.row++;
}
if (this.outputBits >= 8) {
this.buf = (this.codingPos & 1) ? 0 : 0xFF;
this.outputBits -= 8;
if (this.outputBits == 0 && codingLine[this.codingPos] < columns) {
this.codingPos++;
this.outputBits = (codingLine[this.codingPos] -
codingLine[this.codingPos - 1]);
}
} else {
var bits = 8;
this.buf = 0;
do {
if (this.outputBits > bits) {
this.buf <<= bits;
if (!(this.codingPos & 1)) {
this.buf |= 0xFF >> (8 - bits);
}
this.outputBits -= bits;
bits = 0;
} else {
this.buf <<= this.outputBits;
if (!(this.codingPos & 1)) {
this.buf |= 0xFF >> (8 - this.outputBits);
}
bits -= this.outputBits;
this.outputBits = 0;
if (codingLine[this.codingPos] < columns) {
this.codingPos++;
this.outputBits = (codingLine[this.codingPos] -
codingLine[this.codingPos - 1]);
} else if (bits > 0) {
this.buf <<= bits;
bits = 0;
}
}
} while (bits);
}
if (this.black) {
this.buf ^= 0xFF;
}
return this.buf;
};
// This functions returns the code found from the table.
// The start and end parameters set the boundaries for searching the table.
// The limit parameter is optional. Function returns an array with three
// values. The first array element indicates whether a valid code is being
// returned. The second array element is the actual code. The third array
// element indicates whether EOF was reached.
var findTableCode = function ccittFaxStreamFindTableCode(start, end, table,
limit) {
var limitValue = limit || 0;
for (var i = start; i <= end; ++i) {
var code = this.lookBits(i);
if (code == EOF)
return [true, 1, false];
if (i < end)
code <<= end - i;
if (!limitValue || code >= limitValue) {
var p = table[code - limitValue];
if (p[0] == i) {
this.eatBits(i);
return [true, p[1], true];
}
}
}
return [false, 0, false];
};
CCITTFaxStream.prototype.getTwoDimCode =
function ccittFaxStreamGetTwoDimCode() {
var code = 0;
var p;
if (this.eoblock) {
code = this.lookBits(7);
p = twoDimTable[code];
if (p[0] > 0) {
this.eatBits(p[0]);
return p[1];
}
} else {
var result = findTableCode(1, 7, twoDimTable);
if (result[0] && result[2])
return result[1];
}
warn('Bad two dim code');
return EOF;
};
CCITTFaxStream.prototype.getWhiteCode =
function ccittFaxStreamGetWhiteCode() {
var code = 0;
var p;
var n;
if (this.eoblock) {
code = this.lookBits(12);
if (code == EOF)
return 1;
if ((code >> 5) == 0)
p = whiteTable1[code];
else
p = whiteTable2[code >> 3];
if (p[0] > 0) {
this.eatBits(p[0]);
return p[1];
}
} else {
var result = findTableCode(1, 9, whiteTable2);
if (result[0])
return result[1];
result = findTableCode(11, 12, whiteTable1);
if (result[0])
return result[1];
}
warn('bad white code');
this.eatBits(1);
return 1;
};
CCITTFaxStream.prototype.getBlackCode =
function ccittFaxStreamGetBlackCode() {
var code, p;
if (this.eoblock) {
code = this.lookBits(13);
if (code == EOF)
return 1;
if ((code >> 7) == 0)
p = blackTable1[code];
else if ((code >> 9) == 0 && (code >> 7) != 0)
p = blackTable2[(code >> 1) - 64];
else
p = blackTable3[code >> 7];
if (p[0] > 0) {
this.eatBits(p[0]);
return p[1];
}
} else {
var result = findTableCode(2, 6, blackTable3);
if (result[0])
return result[1];
result = findTableCode(7, 12, blackTable2, 64);
if (result[0])
return result[1];
result = findTableCode(10, 13, blackTable1);
if (result[0])
return result[1];
}
warn('bad black code');
this.eatBits(1);
return 1;
};
CCITTFaxStream.prototype.lookBits = function ccittFaxStreamLookBits(n) {
var c;
while (this.inputBits < n) {
if ((c = this.str.getByte()) == null) {
if (this.inputBits == 0)
return EOF;
return ((this.inputBuf << (n - this.inputBits)) &
(0xFFFF >> (16 - n)));
}
this.inputBuf = (this.inputBuf << 8) + c;
this.inputBits += 8;
}
return (this.inputBuf >> (this.inputBits - n)) & (0xFFFF >> (16 - n));
};
CCITTFaxStream.prototype.eatBits = function ccittFaxStreamEatBits(n) {
if ((this.inputBits -= n) < 0)
this.inputBits = 0;
};
return CCITTFaxStream;
})();
var LZWStream = (function LZWStreamClosure() {
function LZWStream(str, earlyChange) {
this.str = str;
this.dict = str.dict;
this.cachedData = 0;
this.bitsCached = 0;
var maxLzwDictionarySize = 4096;
var lzwState = {
earlyChange: earlyChange,
codeLength: 9,
nextCode: 258,
dictionaryValues: new Uint8Array(maxLzwDictionarySize),
dictionaryLengths: new Uint16Array(maxLzwDictionarySize),
dictionaryPrevCodes: new Uint16Array(maxLzwDictionarySize),
currentSequence: new Uint8Array(maxLzwDictionarySize),
currentSequenceLength: 0
};
for (var i = 0; i < 256; ++i) {
lzwState.dictionaryValues[i] = i;
lzwState.dictionaryLengths[i] = 1;
}
this.lzwState = lzwState;
DecodeStream.call(this);
}
LZWStream.prototype = Object.create(DecodeStream.prototype);
LZWStream.prototype.readBits = function lzwStreamReadBits(n) {
var bitsCached = this.bitsCached;
var cachedData = this.cachedData;
while (bitsCached < n) {
var c = this.str.getByte();
if (c == null) {
this.eof = true;
return null;
}
cachedData = (cachedData << 8) | c;
bitsCached += 8;
}
this.bitsCached = (bitsCached -= n);
this.cachedData = cachedData;
this.lastCode = null;
return (cachedData >>> bitsCached) & ((1 << n) - 1);
};
LZWStream.prototype.readBlock = function lzwStreamReadBlock() {
var blockSize = 512;
var estimatedDecodedSize = blockSize * 2, decodedSizeDelta = blockSize;
var i, j, q;
var lzwState = this.lzwState;
if (!lzwState)
return; // eof was found
var earlyChange = lzwState.earlyChange;
var nextCode = lzwState.nextCode;
var dictionaryValues = lzwState.dictionaryValues;
var dictionaryLengths = lzwState.dictionaryLengths;
var dictionaryPrevCodes = lzwState.dictionaryPrevCodes;
var codeLength = lzwState.codeLength;
var prevCode = lzwState.prevCode;
var currentSequence = lzwState.currentSequence;
var currentSequenceLength = lzwState.currentSequenceLength;
var decodedLength = 0;
var currentBufferLength = this.bufferLength;
var buffer = this.ensureBuffer(this.bufferLength + estimatedDecodedSize);
for (i = 0; i < blockSize; i++) {
var code = this.readBits(codeLength);
var hasPrev = currentSequenceLength > 0;
if (code < 256) {
currentSequence[0] = code;
currentSequenceLength = 1;
} else if (code >= 258) {
if (code < nextCode) {
currentSequenceLength = dictionaryLengths[code];
for (j = currentSequenceLength - 1, q = code; j >= 0; j--) {
currentSequence[j] = dictionaryValues[q];
q = dictionaryPrevCodes[q];
}
} else {
currentSequence[currentSequenceLength++] = currentSequence[0];
}
} else if (code == 256) {
codeLength = 9;
nextCode = 258;
currentSequenceLength = 0;
continue;
} else {
this.eof = true;
delete this.lzwState;
break;
}
if (hasPrev) {
dictionaryPrevCodes[nextCode] = prevCode;
dictionaryLengths[nextCode] = dictionaryLengths[prevCode] + 1;
dictionaryValues[nextCode] = currentSequence[0];
nextCode++;
codeLength = (nextCode + earlyChange) & (nextCode + earlyChange - 1) ?
codeLength : Math.min(Math.log(nextCode + earlyChange) /
0.6931471805599453 + 1, 12) | 0;
}
prevCode = code;
decodedLength += currentSequenceLength;
if (estimatedDecodedSize < decodedLength) {
do {
estimatedDecodedSize += decodedSizeDelta;
} while (estimatedDecodedSize < decodedLength);
buffer = this.ensureBuffer(this.bufferLength + estimatedDecodedSize);
}
for (j = 0; j < currentSequenceLength; j++)
buffer[currentBufferLength++] = currentSequence[j];
}
lzwState.nextCode = nextCode;
lzwState.codeLength = codeLength;
lzwState.prevCode = prevCode;
lzwState.currentSequenceLength = currentSequenceLength;
this.bufferLength = currentBufferLength;
};
return LZWStream;
})();