From d25e11bee6ca5ca523884da132d18e1400e077b9 Mon Sep 17 00:00:00 2001 From: Minteck Date: Tue, 24 Aug 2021 14:41:48 +0200 Subject: Initial commit --- node_modules/seek-bzip/lib/bitreader.js | 94 +++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 node_modules/seek-bzip/lib/bitreader.js (limited to 'node_modules/seek-bzip/lib/bitreader.js') diff --git a/node_modules/seek-bzip/lib/bitreader.js b/node_modules/seek-bzip/lib/bitreader.js new file mode 100644 index 0000000..7bcb396 --- /dev/null +++ b/node_modules/seek-bzip/lib/bitreader.js @@ -0,0 +1,94 @@ +/* +node-bzip - a pure-javascript Node.JS module for decoding bzip2 data + +Copyright (C) 2012 Eli Skeggs + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the +"Software"), to deal in the Software without restriction, including +without limitation the rights to use, copy, modify, merge, publish, +distribute, sublicense, and/or sell copies of the Software, and to +permit persons to whom the Software is furnished to do so, subject to +the following conditions: + +The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE +LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +Adapted from bzip2.js, copyright 2011 antimatter15 (antimatter15@gmail.com). + +Based on micro-bunzip by Rob Landley (rob@landley.net). + +Based on bzip2 decompression code by Julian R Seward (jseward@acm.org), +which also acknowledges contributions by Mike Burrows, David Wheeler, +Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten, +Robert Sedgewick, and Jon L. Bentley. +*/ + +var BITMASK = [0x00, 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x3F, 0x7F, 0xFF]; + +// offset in bytes +var BitReader = function(stream) { + this.stream = stream; + this.bitOffset = 0; + this.curByte = 0; + this.hasByte = false; +}; + +BitReader.prototype._ensureByte = function() { + if (!this.hasByte) { + this.curByte = this.stream.readByte(); + this.hasByte = true; + } +}; + +// reads bits from the buffer +BitReader.prototype.read = function(bits) { + var result = 0; + while (bits > 0) { + this._ensureByte(); + var remaining = 8 - this.bitOffset; + // if we're in a byte + if (bits >= remaining) { + result <<= remaining; + result |= BITMASK[remaining] & this.curByte; + this.hasByte = false; + this.bitOffset = 0; + bits -= remaining; + } else { + result <<= bits; + var shift = remaining - bits; + result |= (this.curByte & (BITMASK[bits] << shift)) >> shift; + this.bitOffset += bits; + bits = 0; + } + } + return result; +}; + +// seek to an arbitrary point in the buffer (expressed in bits) +BitReader.prototype.seek = function(pos) { + var n_bit = pos % 8; + var n_byte = (pos - n_bit) / 8; + this.bitOffset = n_bit; + this.stream.seek(n_byte); + this.hasByte = false; +}; + +// reads 6 bytes worth of data using the read method +BitReader.prototype.pi = function() { + var buf = new Buffer(6), i; + for (i = 0; i < buf.length; i++) { + buf[i] = this.read(8); + } + return buf.toString('hex'); +}; + +module.exports = BitReader; -- cgit