/var/www/greso.tech/server/nsm/node_modules/pdf-lib/es/core/streams
Edit: /var/www/greso.tech/server/nsm/node_modules/pdf-lib/es/core/streams/LZWStream.js (5336B)
/*
* Copyright 2012 Mozilla Foundation
*
* The LZWStream class contained in this file is a TypeScript port of the
* JavaScript LZWStream class in Mozilla's pdf.js project, made available
* under the Apache 2.0 open source license.
*/
import { __extends } from "tslib";
import DecodeStream from "./DecodeStream";
var LZWStream = /** @class */ (function (_super) {
__extends(LZWStream, _super);
function LZWStream(stream, maybeLength, earlyChange) {
var _this = _super.call(this, maybeLength) || this;
_this.stream = stream;
_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;
return _this;
}
LZWStream.prototype.readBlock = function () {
var blockSize = 512;
var estimatedDecodedSize = blockSize * 2;
var decodedSizeDelta = blockSize;
var i;
var j;
var 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 || 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;
};
LZWStream.prototype.readBits = function (n) {
var bitsCached = this.bitsCached;
var cachedData = this.cachedData;
while (bitsCached < n) {
var c = this.stream.getByte();
if (c === -1) {
this.eof = true;
return null;
}
cachedData = (cachedData << 8) | c;
bitsCached += 8;
}
this.bitsCached = bitsCached -= n;
this.cachedData = cachedData;
return (cachedData >>> bitsCached) & ((1 << n) - 1);
};
return LZWStream;
}(DecodeStream));
export default LZWStream;
//# sourceMappingURL=LZWStream.js.map