/zlib.js
http://github.com/sbober/pocjs · JavaScript · 464 lines · 383 code · 42 blank · 39 comment · 89 complexity · 6b0250df873f8ac882719af6e52d62e5 MD5 · raw file
- /*
- * Extracted from pdf.js
- * https://github.com/andreasgal/pdf.js
- *
- * Copyright (c) 2011 Mozilla Foundation
- *
- * Contributors: Andreas Gal <gal@mozilla.com>
- * Chris G Jones <cjones@mozilla.com>
- * Shaon Barman <shaon.barman@gmail.com>
- * Vivien Nicolas <21@vingtetun.org>
- * Justin D'Arcangelo <justindarc@gmail.com>
- * Yury Delendik
- *
- * 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.
- */
- var DecodeStream = (function() {
- function constructor() {
- this.pos = 0;
- this.bufferLength = 0;
- this.eof = false;
- this.buffer = null;
- }
- constructor.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 pos = this.pos;
- if (length) {
- this.ensureBuffer(pos + length);
- var 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();
- var end = this.bufferLength;
- }
- 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 constructor;
- })();
- var FlateStream = (function() {
- 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 error(e) {
- throw new Error(e)
- }
- function constructor(bytes) {
- //var bytes = stream.getBytes();
- var bytesPos = 0;
- var cmf = bytes[bytesPos++];
- var flg = bytes[bytesPos++];
- if (cmf == -1 || flg == -1)
- error('Invalid header in flate stream');
- if ((cmf & 0x0f) != 0x08)
- error('Unknown compression method in flate stream');
- if ((((cmf << 8) + flg) % 31) != 0)
- error('Bad FCHECK in flate stream');
- if (flg & 0x20)
- error('FDICT bit set in flate stream');
- this.bytes = bytes;
- this.bytesPos = bytesPos;
- this.codeSize = 0;
- this.codeBuf = 0;
- DecodeStream.call(this);
- }
- constructor.prototype = Object.create(DecodeStream.prototype);
- constructor.prototype.getBits = function(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;
- };
- constructor.prototype.getCode = function(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;
- };
- constructor.prototype.generateHuffmanTable = function(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];
- };
- constructor.prototype.readBlock = function() {
- function repeat(stream, array, len, offset, what) {
- var repeat = stream.getBits(len) + offset;
- while (repeat-- > 0)
- array[i++] = what;
- }
- // 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 = Array(codeLenCodeMap.length);
- var i = 0;
- while (i < numCodeLenCodes)
- 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 Array(codes);
- while (i < codes) {
- var code = this.getCode(codeLenCodeTab);
- if (code == 16) {
- repeat(this, codeLengths, 2, 3, len);
- } else if (code == 17) {
- repeat(this, codeLengths, 3, 3, len = 0);
- } else if (code == 18) {
- repeat(this, codeLengths, 7, 11, len = 0);
- } else {
- codeLengths[i++] = len = code;
- }
- }
- litCodeTable =
- this.generateHuffmanTable(codeLengths.slice(0, numLitCodes));
- distCodeTable =
- this.generateHuffmanTable(codeLengths.slice(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 constructor;
- })();