rewrote streams to be object oriented
This commit is contained in:
sbarman
parent
669776e272
commit
2e581a1563
543
pdf.js
543
pdf.js
@ -71,11 +71,6 @@ var Stream = (function() {
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get length() {
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return this.end - this.start;
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},
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lookByte: function() {
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if (this.pos >= this.end)
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return;
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return this.bytes[this.pos];
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},
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getByte: function() {
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if (this.pos >= this.end)
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return;
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@ -99,10 +94,14 @@ var Stream = (function() {
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return bytes.subarray(pos, end);
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},
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lookChar: function() {
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return String.fromCharCode(this.lookByte());
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if (this.pos >= this.end)
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return;
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return String.fromCharCode(this.bytes[this.pos]);
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},
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getChar: function() {
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return String.fromCharCode(this.getByte());
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if (this.pos >= this.end)
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return;
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return String.fromCharCode(this.bytes[this.pos++]);
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},
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skip: function(n) {
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if (!n)
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@ -137,6 +136,84 @@ var StringStream = (function() {
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return constructor;
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})();
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// super class for the decoding streams
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var DecodeStream = (function() {
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function constructor() {
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this.pos = 0;
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this.bufferLength = 0;
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this.eof = false;
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this.buffer = null;
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}
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constructor.prototype = {
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ensureBuffer: function(requested) {
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var buffer = this.buffer;
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var current = buffer ? buffer.byteLength : 0;
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if (requested < current)
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return buffer;
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var size = 512;
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while (size < requested)
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size <<= 1;
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var buffer2 = Uint8Array(size);
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for (var i = 0; i < current; ++i)
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buffer2[i] = buffer[i];
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return this.buffer = buffer2;
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},
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getByte: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return this.buffer[this.pos++];
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},
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getBytes: function(length) {
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var pos = this.pos;
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this.ensureBuffer(pos + length);
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while (!this.eof && this.bufferLength < pos + length)
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this.readBlock();
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var end = pos + length;
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var bufEnd = this.bufferLength;
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if (end > bufEnd)
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end = bufEnd;
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this.pos = end;
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return this.buffer.subarray(pos, end)
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},
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lookChar: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return String.fromCharCode(this.buffer[this.pos]);
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},
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getChar: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return String.fromCharCode(this.buffer[this.pos++]);
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},
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skip: function(n) {
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if (!n)
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n = 1;
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this.pos += n;
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}
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};
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return constructor;
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})();
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var FlateStream = (function() {
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const codeLenCodeMap = Uint32Array([
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16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
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@ -261,12 +338,11 @@ var FlateStream = (function() {
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this.bytes = bytes;
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this.bytesPos = bytesPos;
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this.eof = false;
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this.codeSize = 0;
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this.codeBuf = 0;
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this.pos = 0;
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this.bufferLength = 0;
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DecodeStream.call(this);
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}
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constructor.prototype = {
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@ -314,64 +390,6 @@ var FlateStream = (function() {
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this.bytesPos = bytesPos;
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return codeVal;
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},
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ensureBuffer: function(requested) {
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var buffer = this.buffer;
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var current = buffer ? buffer.byteLength : 0;
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if (requested < current)
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return buffer;
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var size = 512;
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while (size < requested)
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size <<= 1;
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var buffer2 = Uint8Array(size);
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for (var i = 0; i < current; ++i)
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buffer2[i] = buffer[i];
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return this.buffer = buffer2;
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},
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getByte: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return this.buffer[this.pos++];
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},
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getBytes: function(length) {
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var pos = this.pos;
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while (!this.eof && this.bufferLength < pos + length)
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this.readBlock();
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var end = pos + length;
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var bufEnd = this.bufferLength;
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if (end > bufEnd)
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end = bufEnd;
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this.pos = end;
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return this.buffer.subarray(pos, end)
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},
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lookChar: function() {
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var pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof)
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return;
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this.readBlock();
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}
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return String.fromCharCode(this.buffer[pos]);
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},
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getChar: function() {
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var ch = this.lookChar();
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// shouldnt matter what the position is if we get past the eof
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// so no need to check if ch is undefined
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this.pos++;
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return ch;
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},
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skip: function(n) {
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if (!n)
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n = 1;
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this.pos += n;
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},
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generateHuffmanTable: function(lengths) {
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var n = lengths.length;
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@ -489,8 +507,10 @@ var FlateStream = (function() {
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}
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}
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litCodeTable = this.generateHuffmanTable(codeLengths.slice(0, numLitCodes));
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distCodeTable = this.generateHuffmanTable(codeLengths.slice(numLitCodes, codes));
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litCodeTable = this.generateHuffmanTable(
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codeLengths.slice(0, numLitCodes));
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distCodeTable = this.generateHuffmanTable(
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codeLengths.slice(numLitCodes, codes));
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} else {
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error("Unknown block type in flate stream");
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}
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@ -526,8 +546,199 @@ var FlateStream = (function() {
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}
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};
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var thisPrototype = constructor.prototype;
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var superPrototype = DecodeStream.prototype;
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for (var i in superPrototype) {
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if (!thisPrototype[i])
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thisPrototype[i] = superPrototype[i];
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}
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return constructor;
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})();
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var PredictorStream = (function() {
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function constructor(stream, params) {
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var predictor = this.predictor = params.get("Predictor") || 1;
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if (predictor <= 1)
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return stream; // no prediction
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if (predictor !== 2 && (predictor < 10 || predictor > 15))
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error("Unsupported predictor");
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if (predictor === 2)
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this.readBlock = this.readBlockTiff;
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else
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this.readBlock = this.readBlockPng;
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this.stream = stream;
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this.dict = stream.dict;
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if (params.has("EarlyChange")) {
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error("EarlyChange predictor parameter is not supported");
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}
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var colors = this.colors = params.get("Colors") || 1;
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var bits = this.bits = params.get("BitsPerComponent") || 8;
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var columns = this.columns = params.get("Columns") || 1;
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var pixBytes = this.pixBytes = (colors * bits + 7) >> 3;
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// add an extra pixByte to represent the pixel left of column 0
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var rowBytes = this.rowBytes = (columns * colors * bits + 7) >> 3;
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DecodeStream.call(this);
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}
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constructor.prototype = {
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readBlockTiff : function() {
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var buffer = this.buffer;
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var pos = this.pos;
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var rowBytes = this.rowBytes;
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var pixBytes = this.pixBytes;
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var buffer = this.buffer;
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var bufferLength = this.bufferLength;
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this.ensureBuffer(bufferLength + rowBytes);
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var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
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var bits = this.bits;
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var colors = this.colors;
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var rawBytes = this.stream.getBytes(rowBytes);
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if (bits === 1) {
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var inbuf = 0;
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for (var i = 0; i < rowBytes; ++i) {
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var c = rawBytes[i];
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inBuf = (inBuf << 8) | c;
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// bitwise addition is exclusive or
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// first shift inBuf and then add
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currentRow[i] = (c ^ (inBuf >> colors)) & 0xFF;
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// truncate inBuf (assumes colors < 16)
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inBuf &= 0xFFFF;
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}
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} else if (bits === 8) {
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for (var i = 0; i < colors; ++i)
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currentRow[i] = rawBytes[i];
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for (; i < rowBytes; ++i)
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currentRow[i] = currentRow[i - colors] + rawBytes[i];
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} else {
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var compArray = new Uint8Array(colors + 1);
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var bitMask = (1 << bits) - 1;
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var inbuf = 0, outbut = 0;
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var inbits = 0, outbits = 0;
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var j = 0, k = 0;
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var columns = this.columns;
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for (var i = 0; i < columns; ++i) {
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for (var kk = 0; kk < colors; ++kk) {
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if (inbits < bits) {
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inbuf = (inbuf << 8) | (rawBytes[j++] & 0xFF);
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inbits += 8;
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}
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compArray[kk] = (compArray[kk] +
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(inbuf >> (inbits - bits))) & bitMask;
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inbits -= bits;
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outbuf = (outbuf << bits) | compArray[kk];
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outbits += bits;
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if (outbits >= 8) {
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currentRow[k++] = (outbuf >> (outbits - 8)) & 0xFF;
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outbits -= 8;
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}
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}
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}
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if (outbits > 0) {
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currentRow[k++] = (outbuf << (8 - outbits)) +
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(inbuf & ((1 << (8 - outbits)) - 1))
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}
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}
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this.bufferLength += rowBytes;
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},
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readBlockPng : function() {
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var buffer = this.buffer;
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var pos = this.pos;
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var rowBytes = this.rowBytes;
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var pixBytes = this.pixBytes;
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var predictor = this.stream.getByte();
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var rawBytes = this.stream.getBytes(rowBytes);
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var buffer = this.buffer;
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var bufferLength = this.bufferLength;
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this.ensureBuffer(bufferLength + pixBytes);
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var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
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var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
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if (prevRow.length == 0)
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prevRow = currentRow;
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switch (predictor) {
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case 0:
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break;
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case 1:
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for (var i = 0; i < pixBytes; ++i)
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currentRow[i] = rawBytes[i];
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for (; i < rowBytes; ++i)
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currentRow[i] = (currentRow[i - pixBytes] + rawBytes[i]) & 0xFF;
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break;
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case 2:
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for (var i = 0; i < rowBytes; ++i)
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currentRow[i] = (prevRow[i] + rawBytes[i]) & 0xFF;
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break;
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case 3:
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for (var i = 0; i < pixBytes; ++i)
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currentRow[i] = (prevRow[i] >> 1) + rawBytes[i];
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for (; i < rowBytes; ++i)
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currentRow[i] = (((prevRow[i] + currentRow[i - pixBytes])
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>> 1) + rawBytes[i]) & 0xFF;
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break;
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case 4:
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// we need to save the up left pixels values. the simplest way
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// is to create a new buffer
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for (var i = 0; i < pixBytes; ++i)
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currentRow[i] = rawBytes[i];
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for (; i < rowBytes; ++i) {
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var up = prevRow[i];
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var upLeft = lastRow[i - pixBytes];
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var left = currentRow[i - pixBytes];
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var p = left + up - upLeft;
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var pa = p - left;
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if (pa < 0)
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pa = -pa;
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var pb = p - up;
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if (pb < 0)
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pb = -pb;
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var pc = p - upLeft;
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if (pc < 0)
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pc = -pc;
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var c = rawBytes[i];
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if (pa <= pb && pa <= pc)
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currentRow[i] = left + c;
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else if (pb <= pc)
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currentRow[i] = up + c;
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else
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currentRow[i] = upLeft + c;
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break;
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}
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default:
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error("Unsupported predictor");
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break;
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}
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this.bufferLength += rowBytes;
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},
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};
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var thisPrototype = constructor.prototype;
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var superPrototype = DecodeStream.prototype;
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for (var i in superPrototype) {
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if (!thisPrototype[i])
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thisPrototype[i] = superPrototype[i];
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}
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return constructor;
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})();
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// A JpegStream can't be read directly. We use the platform to render the underlying
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// JPEG data for us.
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var JpegStream = (function() {
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@ -552,196 +763,6 @@ var JpegStream = (function() {
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return constructor;
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})();
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var PredictorStream = (function() {
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function constructor(stream, params) {
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var predictor = this.predictor = params.get("Predictor") || 1;
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if (predictor <= 1)
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return stream; // no prediction
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if (predictor !== 2 && (predictor < 10 || predictor > 15))
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error("Unsupported predictor");
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if (predictor === 2)
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this.readRow = this.readRowTiff;
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else
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this.readRow = this.readRowPng;
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this.stream = stream;
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this.dict = stream.dict;
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if (params.has("EarlyChange")) {
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error("EarlyChange predictor parameter is not supported");
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}
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var colors = this.colors = params.get("Colors") || 1;
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var bits = this.bits = params.get("BitsPerComponent") || 8;
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var columns = this.columns = params.get("Columns") || 1;
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var pixBytes = this.pixBytes = (colors * bits + 7) >> 3;
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// add an extra pixByte to represent the pixel left of column 0
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var rowBytes = this.rowBytes = ((columns * colors * bits + 7) >> 3) + pixBytes;
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this.currentRow = new Uint8Array(rowBytes);
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this.bufferLength = rowBytes;
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this.pos = rowBytes;
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}
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constructor.prototype = {
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readRowTiff : function() {
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var currentRow = this.currentRow;
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var rowBytes = this.rowBytes;
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var pixBytes = this.pixBytes;
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var bits = this.bits;
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var colors = this.colors;
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var rawBytes = this.stream.getBytes(rowBytes - pixBytes);
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if (bits === 1) {
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var inbuf = 0;
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for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j) {
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var c = rawBytes[j];
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inBuf = (inBuf << 8) | c;
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// bitwise addition is exclusive or
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// first shift inBuf and then add
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currentRow[i] = (c ^ (inBuf >> colors)) & 0xFF;
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// truncate inBuf (assumes colors < 16)
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inBuf &= 0xFFFF;
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}
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} else if (bits === 8) {
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for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
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currentRow[i] = currentRow[i - colors] + rawBytes[j];
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} else {
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var compArray = new Uint8Array(colors + 1);
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var bitMask = (1 << bits) - 1;
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var inbuf = 0, outbut = 0;
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var inbits = 0, outbits = 0;
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var j = 0, k = pixBytes;
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var columns = this.columns;
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for (var i = 0; i < columns; ++i) {
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for (var kk = 0; kk < colors; ++kk) {
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if (inbits < bits) {
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inbuf = (inbuf << 8) | (rawBytes[j++] & 0xFF);
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inbits += 8;
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}
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compArray[kk] = (compArray[kk] +
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(inbuf >> (inbits - bits))) & bitMask;
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inbits -= bits;
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outbuf = (outbuf << bits) | compArray[kk];
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outbits += bits;
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if (outbits >= 8) {
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currentRow[k++] = (outbuf >> (outbits - 8)) & 0xFF;
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outbits -= 8;
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}
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}
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}
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if (outbits > 0) {
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currentRow[k++] = (outbuf << (8 - outbits)) +
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(inbuf & ((1 << (8 - outbits)) - 1))
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}
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}
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this.pos = pixBytes;
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},
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readRowPng : function() {
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var currentRow = this.currentRow;
|
||||
|
||||
var rowBytes = this.rowBytes;
|
||||
var pixBytes = this.pixBytes;
|
||||
|
||||
var predictor = this.stream.getByte();
|
||||
var rawBytes = this.stream.getBytes(rowBytes - pixBytes);
|
||||
|
||||
switch (predictor) {
|
||||
case 0:
|
||||
break;
|
||||
case 1:
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = (currentRow[i - pixBytes] + rawBytes[j]) & 0xFF;
|
||||
break;
|
||||
case 2:
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = (currentRow[i] + rawBytes[j]) & 0xFF;
|
||||
break;
|
||||
case 3:
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j)
|
||||
currentRow[i] = (((currentRow[i] + currentRow[i - pixBytes])
|
||||
>> 1) + rawBytes[j]) & 0xFF;
|
||||
break;
|
||||
case 4:
|
||||
// we need to save the up left pixels values. the simplest way
|
||||
// is to create a new buffer
|
||||
var lastRow = currentRow;
|
||||
var currentRow = new Uint8Array(rowBytes);
|
||||
for (var i = pixBytes, j = 0; i < rowBytes; ++i, ++j) {
|
||||
var up = lastRow[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[j];
|
||||
if (pa <= pb && pa <= pc)
|
||||
currentRow[i] = left + c;
|
||||
else if (pb <= pc)
|
||||
currentRow[i] = up + c;
|
||||
else
|
||||
currentRow[i] = upLeft + c;
|
||||
break;
|
||||
this.currentRow = currentRow;
|
||||
}
|
||||
default:
|
||||
error("Unsupported predictor");
|
||||
break;
|
||||
}
|
||||
this.pos = pixBytes;
|
||||
},
|
||||
getByte : function() {
|
||||
if (this.pos >= this.bufferLength)
|
||||
this.readRow();
|
||||
return this.currentRow[this.pos++];
|
||||
},
|
||||
getBytes : function(n) {
|
||||
var i, bytes;
|
||||
bytes = new Uint8Array(n);
|
||||
for (i = 0; i < n; ++i) {
|
||||
if (this.pos >= this.bufferLength)
|
||||
this.readRow();
|
||||
bytes[i] = this.currentRow[this.pos++];
|
||||
}
|
||||
return bytes;
|
||||
},
|
||||
getChar : function() {
|
||||
return String.formCharCode(this.getByte());
|
||||
},
|
||||
lookChar : function() {
|
||||
if (this.pos >= this.bufferLength)
|
||||
this.readRow();
|
||||
return String.formCharCode(this.currentRow[this.pos]);
|
||||
},
|
||||
skip : function(n) {
|
||||
var i;
|
||||
if (!n) {
|
||||
n = 1;
|
||||
}
|
||||
while (n > this.bufferLength - this.pos) {
|
||||
n -= this.bufferLength - this.pos;
|
||||
this.readRow();
|
||||
if (this.bufferLength === 0) break;
|
||||
}
|
||||
this.pos += n;
|
||||
}
|
||||
};
|
||||
|
||||
return constructor;
|
||||
})();
|
||||
|
||||
var DecryptStream = (function() {
|
||||
function constructor(str, fileKey, encAlgorithm, keyLength) {
|
||||
TODO("decrypt stream is not implemented");
|
||||
|
||||
Loading…
Reference in New Issue
Block a user