Sakurai/pdf.js
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Convert src/core/lzw_stream.js to use standard classes

Browse Source
This commit is contained in:
Jonas Jenwald 2021-04-27 13:00:05 +02:00
parent 1f9b134c6a
commit 1f0685cee6
1 changed files with 9 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
src/core/lzw_stream.js
View File

@ -15,9 +15,10 @@
import { DecodeStream } from "./stream.js"; import { DecodeStream } from "./stream.js";
const LZWStream = (function LZWStreamClosure() { class LZWStream extends DecodeStream {
// eslint-disable-next-line no-shadow constructor(str, maybeLength, earlyChange) {
function LZWStream(str, maybeLength, earlyChange) { super(maybeLength);
this.str = str; this.str = str;
this.dict = str.dict; this.dict = str.dict;
this.cachedData = 0; this.cachedData = 0;
@ -39,13 +40,9 @@ const LZWStream = (function LZWStreamClosure() {
lzwState.dictionaryLengths[i] = 1; lzwState.dictionaryLengths[i] = 1;
} }
this.lzwState = lzwState; this.lzwState = lzwState;
DecodeStream.call(this, maybeLength);
} }
LZWStream.prototype = Object.create(DecodeStream.prototype); readBits(n) {
LZWStream.prototype.readBits = function LZWStream_readBits(n) {
let bitsCached = this.bitsCached; let bitsCached = this.bitsCached;
let cachedData = this.cachedData; let cachedData = this.cachedData;
while (bitsCached < n) { while (bitsCached < n) {
@ -61,9 +58,9 @@ const LZWStream = (function LZWStreamClosure() {
this.cachedData = cachedData; this.cachedData = cachedData;
this.lastCode = null; this.lastCode = null;
return (cachedData >>> bitsCached) & ((1 << n) - 1); return (cachedData >>> bitsCached) & ((1 << n) - 1);
}; }
LZWStream.prototype.readBlock = function LZWStream_readBlock() { readBlock() {
const blockSize = 512, const blockSize = 512,
decodedSizeDelta = blockSize; decodedSizeDelta = blockSize;
let estimatedDecodedSize = blockSize * 2; let estimatedDecodedSize = blockSize * 2;
@ -147,9 +144,7 @@ const LZWStream = (function LZWStreamClosure() {
lzwState.currentSequenceLength = currentSequenceLength; lzwState.currentSequenceLength = currentSequenceLength;
this.bufferLength = currentBufferLength; this.bufferLength = currentBufferLength;
}; }
}
return LZWStream;
})();
export { LZWStream }; export { LZWStream };