DecodeStream.call(this);
}
- constructor.prototype = {
- getBits: function(bits) {
- var codeSize = this.codeSize;
- var codeBuf = this.codeBuf;
- var bytes = this.bytes;
- var bytesPos = this.bytesPos;
+ constructor.prototype = Object.create(DecodeStream.prototype);
- 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;
- },
- 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;
+ constructor.prototype.getBits = function(bits) {
+ 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)
+ 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");
- this.codeBuf = (codeBuf >> codeLen);
+ 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;
- },
- 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 = 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;
+ };
+ 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];
+ }
- ++code;
+ // build the table
+ var size = 1 << maxLen;
+ var codes = 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;
}
- }
- }
-
- return [codes, maxLen];
- },
- readBlock: function() {
- function repeat(stream, array, len, offset, what) {
- var repeat = stream.getBits(len) + offset;
- while (repeat-- > 0)
- array[i++] = what;
- }
- var bytes = this.bytes;
- var bytesPos = this.bytesPos;
-
- // read block header
- var hdr = this.getBits(3);
- if (hdr & 1)
- this.eof = true;
- hdr >>= 1;
+ // fill the table entries
+ for (var i = code2; i < size; i += skip)
+ codes[i] = (len << 16) | val;
- var b;
- if (hdr == 0) { // uncompressed block
- 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 != (~this.blockLen & 0xffff))
- error("Bad uncompressed block length in flate stream");
- var bufferLength = this.bufferLength;
- var buffer = this.ensureBuffer(bufferLength + blockLen);
- this.bufferLength = bufferLength + blockLen;
- for (var n = bufferLength; n < blockLen; ++n) {
- if (typeof (b = bytes[bytesPos++]) == "undefined") {
- this.eof = true;
- break;
- }
- buffer[n] = b;
+ ++code;
}
- 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;
- }
- }
+ 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;
+ }
- litCodeTable = this.generateHuffmanTable(
- codeLengths.slice(0, numLitCodes));
- distCodeTable = this.generateHuffmanTable(
- codeLengths.slice(numLitCodes, codes));
- } else {
- error("Unknown block type in flate stream");
+ var bytes = this.bytes;
+ var bytesPos = this.bytesPos;
+
+ // read block header
+ var hdr = this.getBits(3);
+ if (hdr & 1)
+ this.eof = true;
+ hdr >>= 1;
+
+ var b;
+ if (hdr == 0) { // uncompressed block
+ 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 != (~this.blockLen & 0xffff))
+ error("Bad uncompressed block length in flate stream");
+ var bufferLength = this.bufferLength;
+ var buffer = this.ensureBuffer(bufferLength + blockLen);
+ this.bufferLength = bufferLength + blockLen;
+ for (var n = bufferLength; n < blockLen; ++n) {
+ if (typeof (b = bytes[bytesPos++]) == "undefined") {
+ this.eof = true;
+ break;
+ }
+ buffer[n] = b;
}
+ return;
+ }
- var pos = this.bufferLength;
- while (true) {
- var code1 = this.getCode(litCodeTable);
- if (code1 == 256) {
- this.bufferLength = pos;
- return;
- }
- if (code1 < 256) {
- var buffer = this.ensureBuffer(pos + 1);
- buffer[pos++] = code1;
+ 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 {
- 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;
- var buffer = this.ensureBuffer(pos + len);
- for (var k = 0; k < len; ++k, ++pos)
- buffer[pos] = buffer[pos - dist];
+ 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 thisPrototype = constructor.prototype;
- var superPrototype = DecodeStream.prototype;
- for (var i in superPrototype) {
- if (!thisPrototype[i])
- thisPrototype[i] = superPrototype[i];
- }
+ var pos = this.bufferLength;
+ while (true) {
+ var code1 = this.getCode(litCodeTable);
+ if (code1 == 256) {
+ this.bufferLength = pos;
+ return;
+ }
+ if (code1 < 256) {
+ var buffer = this.ensureBuffer(pos + 1);
+ buffer[pos++] = code1;
+ } else {
+ 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;
+ var buffer = this.ensureBuffer(pos + len);
+ for (var k = 0; k < len; ++k, ++pos)
+ buffer[pos] = buffer[pos - dist];
+ }
+ }
+ };
return constructor;
})();
DecodeStream.call(this);
}
- constructor.prototype = {
- readBlockTiff : function() {
- var buffer = this.buffer;
- var pos = this.pos;
+ constructor.prototype = Object.create(DecodeStream.prototype);
- var rowBytes = this.rowBytes;
- var pixBytes = this.pixBytes;
+ constructor.prototype.readBlockTiff = function() {
+ var buffer = this.buffer;
+ var pos = this.pos;
+ var rowBytes = this.rowBytes;
+ var pixBytes = this.pixBytes;
- var buffer = this.buffer;
- var bufferLength = this.bufferLength;
- 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);
-
- if (bits === 1) {
- var inbuf = 0;
- 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 inbuf = 0, outbut = 0;
- var inbits = 0, outbits = 0;
- 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;
- },
- readBlockPng : function() {
- var buffer = this.buffer;
- var pos = this.pos;
- var rowBytes = this.rowBytes;
- var pixBytes = this.pixBytes;
+ var buffer = this.buffer;
+ var bufferLength = this.bufferLength;
+ this.ensureBuffer(bufferLength + rowBytes);
+ var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
- var predictor = this.stream.getByte();
- var rawBytes = this.stream.getBytes(rowBytes);
+ var bits = this.bits;
+ var colors = this.colors;
- var buffer = this.buffer;
- var bufferLength = this.bufferLength;
- this.ensureBuffer(bufferLength + pixBytes);
-
- var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
- var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
- if (prevRow.length == 0)
- prevRow = currentRow;
-
- switch (predictor) {
- case 0:
- 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)
- currentRow[i] = rawBytes[i];
- for (; i < rowBytes; ++i) {
- var up = prevRow[i];
- var upLeft = lastRow[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;
+ var rawBytes = this.stream.getBytes(rowBytes);
+
+ if (bits === 1) {
+ var inbuf = 0;
+ 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 inbuf = 0, outbut = 0;
+ var inbits = 0, outbits = 0;
+ 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;
+ }
}
- default:
- error("Unsupported predictor");
+ }
+ if (outbits > 0) {
+ currentRow[k++] = (outbuf << (8 - outbits)) +
+ (inbuf & ((1 << (8 - outbits)) - 1))
+ }
+ }
+ this.bufferLength += rowBytes;
+ };
+ constructor.prototype.readBlockPng = function() {
+ var buffer = this.buffer;
+ var pos = this.pos;
+
+ var rowBytes = this.rowBytes;
+ var pixBytes = this.pixBytes;
+
+ var predictor = this.stream.getByte();
+ var rawBytes = this.stream.getBytes(rowBytes);
+
+ var buffer = this.buffer;
+ var bufferLength = this.bufferLength;
+ this.ensureBuffer(bufferLength + pixBytes);
+
+ var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
+ var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
+ if (prevRow.length == 0)
+ prevRow = currentRow;
+
+ switch (predictor) {
+ case 0:
+ 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)
+ currentRow[i] = rawBytes[i];
+ for (; i < rowBytes; ++i) {
+ var up = prevRow[i];
+ var upLeft = lastRow[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;
}
- this.bufferLength += rowBytes;
- },
+ default:
+ error("Unsupported predictor");
+ break;
+ }
+ this.bufferLength += rowBytes;
};
-
- var thisPrototype = constructor.prototype;
- var superPrototype = DecodeStream.prototype;
- for (var i in superPrototype) {
- if (!thisPrototype[i])
- thisPrototype[i] = superPrototype[i];
- }
return constructor;
})();
projects / pdf.js.git / commitdiff