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Merge branch 'lzw' of git://github.com/notmasteryet/pdf.js.git

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notmasteryet 2011-08-14 18:22:01 -05:00
commit 03e111308f
2 changed files with 65 additions and 65 deletions
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129
pdf.js
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@ -1989,18 +1989,23 @@ var LZWStream = (function() {
this.dict = str.dict;
this.cachedData = 0;
this.bitsCached = 0;
this.earlyChange = earlyChange;
this.codeLength = 9;
this.nextCode = 258;
this.dictionary = [];
this.currentSequence = null;
for (var i = 0; i < 256; ++i) {
this.dictionary[i] = {
value: i,
firstValue: i,
length: 1
var maxLzwDictionarySize = 4097;
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);
}
@ -2027,34 +2032,44 @@ var LZWStream = (function() {
constructor.prototype.readBlock = function() {
var blockSize = 512;
var decoded = [];
var estimatedDecodedSize = blockSize * 2, decodedSizeDelta = blockSize;
var i, j, q;
var earlyChange = this.earlyChange;
var nextCode = this.nextCode;
var dictionary = this.dictionary;
var codeLength = this.codeLength;
var prevCode = this.prevCode;
var currentSequence = this.currentSequence;
var lzwState = this.lzwState;
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 = !!currentSequence;
var hasPrev = currentSequenceLength > 0;
if (code < 256) {
currentSequence = dictionary[code];
currentSequence[0] = code;
currentSequenceLength = 1;
} else if (code >= 258) {
if (code < nextCode) {
currentSequence = dictionary[code];
currentSequenceLength = dictionaryLengths[code];
for (j = currentSequenceLength - 1, q = code; j >= 0; j--) {
currentSequence[j] = dictionaryValues[q];
q = dictionaryPrevCodes[q];
}
} else {
currentSequence = {
value: currentSequence.firstValue,
length: currentSequence.length + 1,
firstValue: currentSequence.firstValue,
prev: currentSequence
};
currentSequence[currentSequenceLength++] = currentSequence[0];
}
} else if (code == 256) {
codeLength = 9;
nextCode = 258;
currentSequence = null;
currentSequenceLength = 0;
continue;
} else {
this.eof = true;
@ -2062,49 +2077,32 @@ var LZWStream = (function() {
}
if (hasPrev) {
var prevCodeSequence = dictionary[prevCode];
dictionary[nextCode] = {
prev: prevCodeSequence,
length: prevCodeSequence.length + 1,
firstValue: prevCodeSequence.firstValue,
value: currentSequence.firstValue
};
dictionaryPrevCodes[nextCode] = prevCode;
dictionaryLengths[nextCode] = dictionaryLengths[prevCode] + 1;
dictionaryValues[nextCode] = currentSequence[0];
nextCode++;
switch(nextCode + earlyChange) {
case 512:
codeLength = 10;
break;
case 1024:
codeLength = 11;
break;
case 2048:
codeLength = 12;
break;
}
codeLength = (nextCode + earlyChange) & (nextCode + earlyChange - 1) ?
codeLength : Math.min(Math.log(nextCode + earlyChange) /
0.6931471805599453 + 1, 12) | 0;
}
prevCode = code;
decoded.push(currentSequence);
}
this.nextCode = nextCode;
this.codeLength = codeLength;
this.prevCode = prevCode;
this.currentSequence = currentSequence;
var blockLength = 0;
var length = decoded.length;
for (i = 0; i < length; i++)
blockLength += decoded[i].length;
var bufferLength = this.bufferLength;
var buffer = this.ensureBuffer(bufferLength + blockLength);
for (i = 0; i < length; i++) {
var p = decoded[i];
for (q = p.length - 1; q >= 0; q--) {
buffer[bufferLength + q] = p.value;
p = p.prev;
decodedLength += currentSequenceLength;
if (estimatedDecodedSize < decodedLength) {
do {
estimatedDecodedSize += decodedSizeDelta;
} while (estimatedDecodedSize < decodedLength);
buffer = this.ensureBuffer(this.bufferLength + estimatedDecodedSize);
}
bufferLength += decoded[i].length;
for (j = 0; j < currentSequenceLength; j++)
buffer[currentBufferLength++] = currentSequence[j];
}
this.bufferLength = bufferLength;
lzwState.nextCode = nextCode;
lzwState.codeLength = codeLength;
lzwState.prevCode = prevCode;
lzwState.currentSequenceLength = currentSequenceLength;
this.bufferLength = currentBufferLength;
};
return constructor;
@ -2752,7 +2750,8 @@ var Parser = (function() {
if (params) {
if (params.has('EarlyChange'))
earlyChange = params.get('EarlyChange');
return new PredictorStream(new LZWStream(stream, earlyChange), params);
return new PredictorStream(
new LZWStream(stream, earlyChange), params);
}
return new LZWStream(stream, earlyChange);
} else if (name == 'DCTDecode' || name == 'DCT') {

1
web/compatibility.js
View File

@ -40,6 +40,7 @@
// so we can use the TypedArray as well
window.Uint32Array = TypedArray;
window.Int32Array = TypedArray;
window.Uint16Array = TypedArray;
})();
// Object.create() ?