94 lines
2.9 KiB
JavaScript
94 lines
2.9 KiB
JavaScript
var through = require('through');
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var bz2 = require('./lib/bzip2');
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var bitIterator = require('./lib/bit_iterator');
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module.exports = unbzip2Stream;
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function unbzip2Stream() {
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var bufferQueue = [];
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var hasBytes = 0;
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var blockSize = 0;
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var broken = false;
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var done = false;
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var bitReader = null;
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var streamCRC = null;
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function decompressBlock(push){
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if(!blockSize){
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blockSize = bz2.header(bitReader);
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//console.error("got header of", blockSize);
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streamCRC = 0;
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return true;
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}else{
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var bufsize = 100000 * blockSize;
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var buf = new Int32Array(bufsize);
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var chunk = [];
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var f = function(b) {
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chunk.push(b);
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};
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streamCRC = bz2.decompress(bitReader, f, buf, bufsize, streamCRC);
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if (streamCRC === null) {
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// reset for next bzip2 header
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blockSize = 0;
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return false;
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}else{
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//console.error('decompressed', chunk.length,'bytes');
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push(Buffer.from(chunk));
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return true;
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}
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}
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}
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var outlength = 0;
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function decompressAndQueue(stream) {
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if (broken) return;
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try {
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return decompressBlock(function(d) {
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stream.queue(d);
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if (d !== null) {
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//console.error('write at', outlength.toString(16));
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outlength += d.length;
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} else {
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//console.error('written EOS');
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}
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});
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} catch(e) {
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//console.error(e);
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stream.emit('error', e);
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broken = true;
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return false;
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}
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}
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return through(
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function write(data) {
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//console.error('received', data.length,'bytes in', typeof data);
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bufferQueue.push(data);
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hasBytes += data.length;
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if (bitReader === null) {
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bitReader = bitIterator(function() {
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return bufferQueue.shift();
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});
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}
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while (!broken && hasBytes - bitReader.bytesRead + 1 >= ((25000 + 100000 * blockSize) || 4)){
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//console.error('decompressing with', hasBytes - bitReader.bytesRead + 1, 'bytes in buffer');
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decompressAndQueue(this);
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}
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},
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function end(x) {
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//console.error(x,'last compressing with', hasBytes, 'bytes in buffer');
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while (!broken && bitReader && hasBytes > bitReader.bytesRead){
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decompressAndQueue(this);
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}
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if (!broken) {
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if (streamCRC !== null)
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this.emit('error', new Error("input stream ended prematurely"));
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this.queue(null);
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}
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}
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);
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}
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