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AirScout/DotNetZip/BZip2/BZip2InputStream.cs

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46 KiB
C#
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// BZip2InputStream.cs
// ------------------------------------------------------------------
//
// Copyright (c) 2011 Dino Chiesa.
// All rights reserved.
//
// This code module is part of DotNetZip, a zipfile class library.
//
// ------------------------------------------------------------------
//
// This code is licensed under the Microsoft Public License.
// See the file License.txt for the license details.
// More info on: http://dotnetzip.codeplex.com
//
// ------------------------------------------------------------------
//
// Last Saved: <2011-July-31 11:57:32>
//
// ------------------------------------------------------------------
//
// This module defines the BZip2InputStream class, which is a decompressing
// stream that handles BZIP2. This code is derived from Apache commons source code.
// The license below applies to the original Apache code.
//
// ------------------------------------------------------------------
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/*
* This package is based on the work done by Keiron Liddle, Aftex Software
* <keiron@aftexsw.com> to whom the Ant project is very grateful for his
* great code.
*/
// compile: msbuild
// not: csc.exe /t:library /debug+ /out:Ionic.BZip2.dll BZip2InputStream.cs BCRC32.cs Rand.cs
using System;
using System.IO;
namespace Ionic.BZip2
{
/// <summary>
/// A read-only decorator stream that performs BZip2 decompression on Read.
/// </summary>
public class BZip2InputStream : System.IO.Stream
{
bool _disposed;
bool _leaveOpen;
Int64 totalBytesRead;
private int last;
/* for undoing the Burrows-Wheeler transform */
private int origPtr;
// blockSize100k: 0 .. 9.
//
// This var name is a misnomer. The actual block size is 100000
// * blockSize100k. (not 100k * blocksize100k)
private int blockSize100k;
private bool blockRandomised;
private int bsBuff;
private int bsLive;
private readonly Ionic.Crc.CRC32 crc = new Ionic.Crc.CRC32(true);
private int nInUse;
private Stream input;
private int currentChar = -1;
/// <summary>
/// Compressor State
/// </summary>
enum CState
{
EOF = 0,
START_BLOCK = 1,
RAND_PART_A = 2,
RAND_PART_B = 3,
RAND_PART_C = 4,
NO_RAND_PART_A = 5,
NO_RAND_PART_B = 6,
NO_RAND_PART_C = 7,
}
private CState currentState = CState.START_BLOCK;
private uint storedBlockCRC, storedCombinedCRC;
private uint computedBlockCRC, computedCombinedCRC;
// Variables used by setup* methods exclusively
private int su_count;
private int su_ch2;
private int su_chPrev;
private int su_i2;
private int su_j2;
private int su_rNToGo;
private int su_rTPos;
private int su_tPos;
private char su_z;
private BZip2InputStream.DecompressionState data;
/// <summary>
/// Create a BZip2InputStream, wrapping it around the given input Stream.
/// </summary>
/// <remarks>
/// <para>
/// The input stream will be closed when the BZip2InputStream is closed.
/// </para>
/// </remarks>
/// <param name='input'>The stream from which to read compressed data</param>
public BZip2InputStream(Stream input)
: this(input, false)
{}
/// <summary>
/// Create a BZip2InputStream with the given stream, and
/// specifying whether to leave the wrapped stream open when
/// the BZip2InputStream is closed.
/// </summary>
/// <param name='input'>The stream from which to read compressed data</param>
/// <param name='leaveOpen'>
/// Whether to leave the input stream open, when the BZip2InputStream closes.
/// </param>
///
/// <example>
///
/// This example reads a bzip2-compressed file, decompresses it,
/// and writes the decompressed data into a newly created file.
///
/// <code>
/// var fname = "logfile.log.bz2";
/// using (var fs = File.OpenRead(fname))
/// {
/// using (var decompressor = new Ionic.BZip2.BZip2InputStream(fs))
/// {
/// var outFname = fname + ".decompressed";
/// using (var output = File.Create(outFname))
/// {
/// byte[] buffer = new byte[2048];
/// int n;
/// while ((n = decompressor.Read(buffer, 0, buffer.Length)) > 0)
/// {
/// output.Write(buffer, 0, n);
/// }
/// }
/// }
/// }
/// </code>
/// </example>
public BZip2InputStream(Stream input, bool leaveOpen)
: base()
{
this.input = input;
this._leaveOpen = leaveOpen;
init();
}
/// <summary>
/// Read data from the stream.
/// </summary>
///
/// <remarks>
/// <para>
/// To decompress a BZip2 data stream, create a <c>BZip2InputStream</c>,
/// providing a stream that reads compressed data. Then call Read() on
/// that <c>BZip2InputStream</c>, and the data read will be decompressed
/// as you read.
/// </para>
///
/// <para>
/// A <c>BZip2InputStream</c> can be used only for <c>Read()</c>, not for <c>Write()</c>.
/// </para>
/// </remarks>
///
/// <param name="buffer">The buffer into which the read data should be placed.</param>
/// <param name="offset">the offset within that data array to put the first byte read.</param>
/// <param name="count">the number of bytes to read.</param>
/// <returns>the number of bytes actually read</returns>
public override int Read(byte[] buffer, int offset, int count)
{
if (offset < 0)
throw new IndexOutOfRangeException(String.Format("offset ({0}) must be > 0", offset));
if (count < 0)
throw new IndexOutOfRangeException(String.Format("count ({0}) must be > 0", count));
if (offset + count > buffer.Length)
throw new IndexOutOfRangeException(String.Format("offset({0}) count({1}) bLength({2})",
offset, count, buffer.Length));
if (this.input == null)
throw new IOException("the stream is not open");
int hi = offset + count;
int destOffset = offset;
for (int b; (destOffset < hi) && ((b = ReadByte()) >= 0);)
{
buffer[destOffset++] = (byte) b;
}
return (destOffset == offset) ? -1 : (destOffset - offset);
}
private void MakeMaps()
{
bool[] inUse = this.data.inUse;
byte[] seqToUnseq = this.data.seqToUnseq;
int n = 0;
for (int i = 0; i < 256; i++)
{
if (inUse[i])
seqToUnseq[n++] = (byte) i;
}
this.nInUse = n;
}
/// <summary>
/// Read a single byte from the stream.
/// </summary>
/// <returns>the byte read from the stream, or -1 if EOF</returns>
public override int ReadByte()
{
int retChar = this.currentChar;
totalBytesRead++;
switch (this.currentState)
{
case CState.EOF:
return -1;
case CState.START_BLOCK:
throw new IOException("bad state");
case CState.RAND_PART_A:
throw new IOException("bad state");
case CState.RAND_PART_B:
SetupRandPartB();
break;
case CState.RAND_PART_C:
SetupRandPartC();
break;
case CState.NO_RAND_PART_A:
throw new IOException("bad state");
case CState.NO_RAND_PART_B:
SetupNoRandPartB();
break;
case CState.NO_RAND_PART_C:
SetupNoRandPartC();
break;
default:
throw new IOException("bad state");
}
return retChar;
}
/// <summary>
/// Indicates whether the stream can be read.
/// </summary>
/// <remarks>
/// The return value depends on whether the captive stream supports reading.
/// </remarks>
public override bool CanRead
{
get
{
if (_disposed) throw new ObjectDisposedException("BZip2Stream");
return this.input.CanRead;
}
}
/// <summary>
/// Indicates whether the stream supports Seek operations.
/// </summary>
/// <remarks>
/// Always returns false.
/// </remarks>
public override bool CanSeek
{
get { return false; }
}
/// <summary>
/// Indicates whether the stream can be written.
/// </summary>
/// <remarks>
/// The return value depends on whether the captive stream supports writing.
/// </remarks>
public override bool CanWrite
{
get
{
if (_disposed) throw new ObjectDisposedException("BZip2Stream");
return input.CanWrite;
}
}
/// <summary>
/// Flush the stream.
/// </summary>
public override void Flush()
{
if (_disposed) throw new ObjectDisposedException("BZip2Stream");
input.Flush();
}
/// <summary>
/// Reading this property always throws a <see cref="NotImplementedException"/>.
/// </summary>
public override long Length
{
get { throw new NotImplementedException(); }
}
/// <summary>
/// The position of the stream pointer.
/// </summary>
///
/// <remarks>
/// Setting this property always throws a <see
/// cref="NotImplementedException"/>. Reading will return the
/// total number of uncompressed bytes read in.
/// </remarks>
public override long Position
{
get
{
return this.totalBytesRead;
}
set { throw new NotImplementedException(); }
}
/// <summary>
/// Calling this method always throws a <see cref="NotImplementedException"/>.
/// </summary>
/// <param name="offset">this is irrelevant, since it will always throw!</param>
/// <param name="origin">this is irrelevant, since it will always throw!</param>
/// <returns>irrelevant!</returns>
public override long Seek(long offset, System.IO.SeekOrigin origin)
{
throw new NotImplementedException();
}
/// <summary>
/// Calling this method always throws a <see cref="NotImplementedException"/>.
/// </summary>
/// <param name="value">this is irrelevant, since it will always throw!</param>
public override void SetLength(long value)
{
throw new NotImplementedException();
}
/// <summary>
/// Calling this method always throws a <see cref="NotImplementedException"/>.
/// </summary>
/// <param name='buffer'>this parameter is never used</param>
/// <param name='offset'>this parameter is never used</param>
/// <param name='count'>this parameter is never used</param>
public override void Write(byte[] buffer, int offset, int count)
{
throw new NotImplementedException();
}
/// <summary>
/// Dispose the stream.
/// </summary>
/// <param name="disposing">
/// indicates whether the Dispose method was invoked by user code.
/// </param>
protected override void Dispose(bool disposing)
{
try
{
if (!_disposed)
{
if (disposing && (this.input != null))
this.input.Close();
_disposed = true;
}
}
finally
{
base.Dispose(disposing);
}
}
void init()
{
if (null == this.input)
throw new IOException("No input Stream");
if (!this.input.CanRead)
throw new IOException("Unreadable input Stream");
CheckMagicChar('B', 0);
CheckMagicChar('Z', 1);
CheckMagicChar('h', 2);
int blockSize = this.input.ReadByte();
if ((blockSize < '1') || (blockSize > '9'))
throw new IOException("Stream is not BZip2 formatted: illegal "
+ "blocksize " + (char) blockSize);
this.blockSize100k = blockSize - '0';
InitBlock();
SetupBlock();
}
void CheckMagicChar(char expected, int position)
{
int magic = this.input.ReadByte();
if (magic != (int)expected)
{
var msg = String.Format("Not a valid BZip2 stream. byte {0}, expected '{1}', got '{2}'",
position, (int)expected, magic);
throw new IOException(msg);
}
}
void InitBlock()
{
char magic0 = bsGetUByte();
char magic1 = bsGetUByte();
char magic2 = bsGetUByte();
char magic3 = bsGetUByte();
char magic4 = bsGetUByte();
char magic5 = bsGetUByte();
if (magic0 == 0x17 && magic1 == 0x72 && magic2 == 0x45
&& magic3 == 0x38 && magic4 == 0x50 && magic5 == 0x90)
{
complete(); // end of file
}
else if (magic0 != 0x31 ||
magic1 != 0x41 ||
magic2 != 0x59 ||
magic3 != 0x26 ||
magic4 != 0x53 ||
magic5 != 0x59)
{
this.currentState = CState.EOF;
var msg = String.Format("bad block header at offset 0x{0:X}",
this.input.Position);
throw new IOException(msg);
}
else
{
this.storedBlockCRC = bsGetInt();
// Console.WriteLine(" stored block CRC : {0:X8}", this.storedBlockCRC);
this.blockRandomised = (GetBits(1) == 1);
// Lazily allocate data
if (this.data == null)
this.data = new DecompressionState(this.blockSize100k);
// currBlockNo++;
getAndMoveToFrontDecode();
this.crc.Reset();
this.currentState = CState.START_BLOCK;
}
}
private void EndBlock()
{
this.computedBlockCRC = (uint)this.crc.Crc32Result;
// A bad CRC is considered a fatal error.
if (this.storedBlockCRC != this.computedBlockCRC)
{
// make next blocks readable without error
// (repair feature, not yet documented, not tested)
// this.computedCombinedCRC = (this.storedCombinedCRC << 1)
// | (this.storedCombinedCRC >> 31);
// this.computedCombinedCRC ^= this.storedBlockCRC;
var msg = String.Format("BZip2 CRC error (expected {0:X8}, computed {1:X8})",
this.storedBlockCRC, this.computedBlockCRC);
throw new IOException(msg);
}
// Console.WriteLine(" combined CRC (before): {0:X8}", this.computedCombinedCRC);
this.computedCombinedCRC = (this.computedCombinedCRC << 1)
| (this.computedCombinedCRC >> 31);
this.computedCombinedCRC ^= this.computedBlockCRC;
// Console.WriteLine(" computed block CRC : {0:X8}", this.computedBlockCRC);
// Console.WriteLine(" combined CRC (after) : {0:X8}", this.computedCombinedCRC);
// Console.WriteLine();
}
private void complete()
{
this.storedCombinedCRC = bsGetInt();
this.currentState = CState.EOF;
this.data = null;
if (this.storedCombinedCRC != this.computedCombinedCRC)
{
var msg = String.Format("BZip2 CRC error (expected {0:X8}, computed {1:X8})",
this.storedCombinedCRC, this.computedCombinedCRC);
throw new IOException(msg);
}
}
/// <summary>
/// Close the stream.
/// </summary>
public override void Close()
{
Stream inShadow = this.input;
if (inShadow != null)
{
try
{
if (!this._leaveOpen)
inShadow.Close();
}
finally
{
this.data = null;
this.input = null;
}
}
}
/// <summary>
/// Read n bits from input, right justifying the result.
/// </summary>
/// <remarks>
/// <para>
/// For example, if you read 1 bit, the result is either 0
/// or 1.
/// </para>
/// </remarks>
/// <param name ="n">
/// The number of bits to read, always between 1 and 32.
/// </param>
private int GetBits(int n)
{
int bsLiveShadow = this.bsLive;
int bsBuffShadow = this.bsBuff;
if (bsLiveShadow < n)
{
do
{
int thech = this.input.ReadByte();
if (thech < 0)
throw new IOException("unexpected end of stream");
// Console.WriteLine("R {0:X2}", thech);
bsBuffShadow = (bsBuffShadow << 8) | thech;
bsLiveShadow += 8;
} while (bsLiveShadow < n);
this.bsBuff = bsBuffShadow;
}
this.bsLive = bsLiveShadow - n;
return (bsBuffShadow >> (bsLiveShadow - n)) & ((1 << n) - 1);
}
// private bool bsGetBit()
// {
// int bsLiveShadow = this.bsLive;
// int bsBuffShadow = this.bsBuff;
//
// if (bsLiveShadow < 1)
// {
// int thech = this.input.ReadByte();
//
// if (thech < 0)
// {
// throw new IOException("unexpected end of stream");
// }
//
// bsBuffShadow = (bsBuffShadow << 8) | thech;
// bsLiveShadow += 8;
// this.bsBuff = bsBuffShadow;
// }
//
// this.bsLive = bsLiveShadow - 1;
// return ((bsBuffShadow >> (bsLiveShadow - 1)) & 1) != 0;
// }
private bool bsGetBit()
{
int bit = GetBits(1);
return bit != 0;
}
private char bsGetUByte()
{
return (char) GetBits(8);
}
private uint bsGetInt()
{
return (uint)((((((GetBits(8) << 8) | GetBits(8)) << 8) | GetBits(8)) << 8) | GetBits(8));
}
/**
* Called by createHuffmanDecodingTables() exclusively.
*/
private static void hbCreateDecodeTables(int[] limit,
int[] bbase, int[] perm, char[] length,
int minLen, int maxLen, int alphaSize)
{
for (int i = minLen, pp = 0; i <= maxLen; i++)
{
for (int j = 0; j < alphaSize; j++)
{
if (length[j] == i)
{
perm[pp++] = j;
}
}
}
for (int i = BZip2.MaxCodeLength; --i > 0;)
{
bbase[i] = 0;
limit[i] = 0;
}
for (int i = 0; i < alphaSize; i++)
{
bbase[length[i] + 1]++;
}
for (int i = 1, b = bbase[0]; i < BZip2.MaxCodeLength; i++)
{
b += bbase[i];
bbase[i] = b;
}
for (int i = minLen, vec = 0, b = bbase[i]; i <= maxLen; i++)
{
int nb = bbase[i + 1];
vec += nb - b;
b = nb;
limit[i] = vec - 1;
vec <<= 1;
}
for (int i = minLen + 1; i <= maxLen; i++)
{
bbase[i] = ((limit[i - 1] + 1) << 1) - bbase[i];
}
}
private void recvDecodingTables()
{
var s = this.data;
bool[] inUse = s.inUse;
byte[] pos = s.recvDecodingTables_pos;
//byte[] selector = s.selector;
int inUse16 = 0;
/* Receive the mapping table */
for (int i = 0; i < 16; i++)
{
if (bsGetBit())
{
inUse16 |= 1 << i;
}
}
for (int i = 256; --i >= 0;)
{
inUse[i] = false;
}
for (int i = 0; i < 16; i++)
{
if ((inUse16 & (1 << i)) != 0)
{
int i16 = i << 4;
for (int j = 0; j < 16; j++)
{
if (bsGetBit())
{
inUse[i16 + j] = true;
}
}
}
}
MakeMaps();
int alphaSize = this.nInUse + 2;
/* Now the selectors */
int nGroups = GetBits(3);
int nSelectors = GetBits(15);
for (int i = 0; i < nSelectors; i++)
{
int j = 0;
while (bsGetBit())
{
j++;
}
s.selectorMtf[i] = (byte) j;
}
/* Undo the MTF values for the selectors. */
for (int v = nGroups; --v >= 0;)
{
pos[v] = (byte) v;
}
for (int i = 0; i < nSelectors; i++)
{
int v = s.selectorMtf[i];
byte tmp = pos[v];
while (v > 0)
{
// nearly all times v is zero, 4 in most other cases
pos[v] = pos[v - 1];
v--;
}
pos[0] = tmp;
s.selector[i] = tmp;
}
char[][] len = s.temp_charArray2d;
/* Now the coding tables */
for (int t = 0; t < nGroups; t++)
{
int curr = GetBits(5);
char[] len_t = len[t];
for (int i = 0; i < alphaSize; i++)
{
while (bsGetBit())
{
curr += bsGetBit() ? -1 : 1;
}
len_t[i] = (char) curr;
}
}
// finally create the Huffman tables
createHuffmanDecodingTables(alphaSize, nGroups);
}
/**
* Called by recvDecodingTables() exclusively.
*/
private void createHuffmanDecodingTables(int alphaSize,
int nGroups)
{
var s = this.data;
char[][] len = s.temp_charArray2d;
for (int t = 0; t < nGroups; t++)
{
int minLen = 32;
int maxLen = 0;
char[] len_t = len[t];
for (int i = alphaSize; --i >= 0;)
{
char lent = len_t[i];
if (lent > maxLen)
maxLen = lent;
if (lent < minLen)
minLen = lent;
}
hbCreateDecodeTables(s.gLimit[t], s.gBase[t], s.gPerm[t], len[t], minLen,
maxLen, alphaSize);
s.gMinlen[t] = minLen;
}
}
private void getAndMoveToFrontDecode()
{
var s = this.data;
this.origPtr = GetBits(24);
if (this.origPtr < 0)
throw new IOException("BZ_DATA_ERROR");
if (this.origPtr > 10 + BZip2.BlockSizeMultiple * this.blockSize100k)
throw new IOException("BZ_DATA_ERROR");
recvDecodingTables();
byte[] yy = s.getAndMoveToFrontDecode_yy;
int limitLast = this.blockSize100k * BZip2.BlockSizeMultiple;
/*
* Setting up the unzftab entries here is not strictly necessary, but it
* does save having to do it later in a separate pass, and so saves a
* block's worth of cache misses.
*/
for (int i = 256; --i >= 0;)
{
yy[i] = (byte) i;
s.unzftab[i] = 0;
}
int groupNo = 0;
int groupPos = BZip2.G_SIZE - 1;
int eob = this.nInUse + 1;
int nextSym = getAndMoveToFrontDecode0(0);
int bsBuffShadow = this.bsBuff;
int bsLiveShadow = this.bsLive;
int lastShadow = -1;
int zt = s.selector[groupNo] & 0xff;
int[] base_zt = s.gBase[zt];
int[] limit_zt = s.gLimit[zt];
int[] perm_zt = s.gPerm[zt];
int minLens_zt = s.gMinlen[zt];
while (nextSym != eob)
{
if ((nextSym == BZip2.RUNA) || (nextSym == BZip2.RUNB))
{
int es = -1;
for (int n = 1; true; n <<= 1)
{
if (nextSym == BZip2.RUNA)
{
es += n;
}
else if (nextSym == BZip2.RUNB)
{
es += n << 1;
}
else
{
break;
}
if (groupPos == 0)
{
groupPos = BZip2.G_SIZE - 1;
zt = s.selector[++groupNo] & 0xff;
base_zt = s.gBase[zt];
limit_zt = s.gLimit[zt];
perm_zt = s.gPerm[zt];
minLens_zt = s.gMinlen[zt];
}
else
{
groupPos--;
}
int zn = minLens_zt;
// Inlined:
// int zvec = GetBits(zn);
while (bsLiveShadow < zn)
{
int thech = this.input.ReadByte();
if (thech >= 0)
{
bsBuffShadow = (bsBuffShadow << 8) | thech;
bsLiveShadow += 8;
continue;
}
else
{
throw new IOException("unexpected end of stream");
}
}
int zvec = (bsBuffShadow >> (bsLiveShadow - zn))
& ((1 << zn) - 1);
bsLiveShadow -= zn;
while (zvec > limit_zt[zn])
{
zn++;
while (bsLiveShadow < 1)
{
int thech = this.input.ReadByte();
if (thech >= 0)
{
bsBuffShadow = (bsBuffShadow << 8) | thech;
bsLiveShadow += 8;
continue;
}
else
{
throw new IOException("unexpected end of stream");
}
}
bsLiveShadow--;
zvec = (zvec << 1)
| ((bsBuffShadow >> bsLiveShadow) & 1);
}
nextSym = perm_zt[zvec - base_zt[zn]];
}
byte ch = s.seqToUnseq[yy[0]];
s.unzftab[ch & 0xff] += es + 1;
while (es-- >= 0)
{
s.ll8[++lastShadow] = ch;
}
if (lastShadow >= limitLast)
throw new IOException("block overrun");
}
else
{
if (++lastShadow >= limitLast)
throw new IOException("block overrun");
byte tmp = yy[nextSym - 1];
s.unzftab[s.seqToUnseq[tmp] & 0xff]++;
s.ll8[lastShadow] = s.seqToUnseq[tmp];
/*
* This loop is hammered during decompression, hence avoid
* native method call overhead of System.Buffer.BlockCopy for very
* small ranges to copy.
*/
if (nextSym <= 16)
{
for (int j = nextSym - 1; j > 0;)
{
yy[j] = yy[--j];
}
}
else
{
System.Buffer.BlockCopy(yy, 0, yy, 1, nextSym - 1);
}
yy[0] = tmp;
if (groupPos == 0)
{
groupPos = BZip2.G_SIZE - 1;
zt = s.selector[++groupNo] & 0xff;
base_zt = s.gBase[zt];
limit_zt = s.gLimit[zt];
perm_zt = s.gPerm[zt];
minLens_zt = s.gMinlen[zt];
}
else
{
groupPos--;
}
int zn = minLens_zt;
// Inlined:
// int zvec = GetBits(zn);
while (bsLiveShadow < zn)
{
int thech = this.input.ReadByte();
if (thech >= 0)
{
bsBuffShadow = (bsBuffShadow << 8) | thech;
bsLiveShadow += 8;
continue;
}
else
{
throw new IOException("unexpected end of stream");
}
}
int zvec = (bsBuffShadow >> (bsLiveShadow - zn))
& ((1 << zn) - 1);
bsLiveShadow -= zn;
while (zvec > limit_zt[zn])
{
zn++;
while (bsLiveShadow < 1)
{
int thech = this.input.ReadByte();
if (thech >= 0)
{
bsBuffShadow = (bsBuffShadow << 8) | thech;
bsLiveShadow += 8;
continue;
}
else
{
throw new IOException("unexpected end of stream");
}
}
bsLiveShadow--;
zvec = (zvec << 1) | ((bsBuffShadow >> bsLiveShadow) & 1);
}
nextSym = perm_zt[zvec - base_zt[zn]];
}
}
this.last = lastShadow;
this.bsLive = bsLiveShadow;
this.bsBuff = bsBuffShadow;
}
private int getAndMoveToFrontDecode0(int groupNo)
{
var s = this.data;
int zt = s.selector[groupNo] & 0xff;
int[] limit_zt = s.gLimit[zt];
int zn = s.gMinlen[zt];
int zvec = GetBits(zn);
int bsLiveShadow = this.bsLive;
int bsBuffShadow = this.bsBuff;
while (zvec > limit_zt[zn])
{
zn++;
while (bsLiveShadow < 1)
{
int thech = this.input.ReadByte();
if (thech >= 0)
{
bsBuffShadow = (bsBuffShadow << 8) | thech;
bsLiveShadow += 8;
continue;
}
else
{
throw new IOException("unexpected end of stream");
}
}
bsLiveShadow--;
zvec = (zvec << 1) | ((bsBuffShadow >> bsLiveShadow) & 1);
}
this.bsLive = bsLiveShadow;
this.bsBuff = bsBuffShadow;
return s.gPerm[zt][zvec - s.gBase[zt][zn]];
}
private void SetupBlock()
{
if (this.data == null)
return;
int i;
var s = this.data;
int[] tt = s.initTT(this.last + 1);
// xxxx
/* Check: unzftab entries in range. */
for (i = 0; i <= 255; i++)
{
if (s.unzftab[i] < 0 || s.unzftab[i] > this.last)
throw new Exception("BZ_DATA_ERROR");
}
/* Actually generate cftab. */
s.cftab[0] = 0;
for (i = 1; i <= 256; i++) s.cftab[i] = s.unzftab[i-1];
for (i = 1; i <= 256; i++) s.cftab[i] += s.cftab[i-1];
/* Check: cftab entries in range. */
for (i = 0; i <= 256; i++)
{
if (s.cftab[i] < 0 || s.cftab[i] > this.last+1)
{
var msg = String.Format("BZ_DATA_ERROR: cftab[{0}]={1} last={2}",
i, s.cftab[i], this.last);
throw new Exception(msg);
}
}
/* Check: cftab entries non-descending. */
for (i = 1; i <= 256; i++)
{
if (s.cftab[i-1] > s.cftab[i])
throw new Exception("BZ_DATA_ERROR");
}
int lastShadow;
for (i = 0, lastShadow = this.last; i <= lastShadow; i++)
{
tt[s.cftab[s.ll8[i] & 0xff]++] = i;
}
if ((this.origPtr < 0) || (this.origPtr >= tt.Length))
throw new IOException("stream corrupted");
this.su_tPos = tt[this.origPtr];
this.su_count = 0;
this.su_i2 = 0;
this.su_ch2 = 256; /* not a valid 8-bit byte value?, and not EOF */
if (this.blockRandomised)
{
this.su_rNToGo = 0;
this.su_rTPos = 0;
SetupRandPartA();
}
else
{
SetupNoRandPartA();
}
}
private void SetupRandPartA()
{
if (this.su_i2 <= this.last)
{
this.su_chPrev = this.su_ch2;
int su_ch2Shadow = this.data.ll8[this.su_tPos] & 0xff;
this.su_tPos = this.data.tt[this.su_tPos];
if (this.su_rNToGo == 0)
{
this.su_rNToGo = Rand.Rnums(this.su_rTPos) - 1;
if (++this.su_rTPos == 512)
{
this.su_rTPos = 0;
}
}
else
{
this.su_rNToGo--;
}
this.su_ch2 = su_ch2Shadow ^= (this.su_rNToGo == 1) ? 1 : 0;
this.su_i2++;
this.currentChar = su_ch2Shadow;
this.currentState = CState.RAND_PART_B;
this.crc.UpdateCRC((byte)su_ch2Shadow);
}
else
{
EndBlock();
InitBlock();
SetupBlock();
}
}
private void SetupNoRandPartA()
{
if (this.su_i2 <= this.last)
{
this.su_chPrev = this.su_ch2;
int su_ch2Shadow = this.data.ll8[this.su_tPos] & 0xff;
this.su_ch2 = su_ch2Shadow;
this.su_tPos = this.data.tt[this.su_tPos];
this.su_i2++;
this.currentChar = su_ch2Shadow;
this.currentState = CState.NO_RAND_PART_B;
this.crc.UpdateCRC((byte)su_ch2Shadow);
}
else
{
this.currentState = CState.NO_RAND_PART_A;
EndBlock();
InitBlock();
SetupBlock();
}
}
private void SetupRandPartB()
{
if (this.su_ch2 != this.su_chPrev)
{
this.currentState = CState.RAND_PART_A;
this.su_count = 1;
SetupRandPartA();
}
else if (++this.su_count >= 4)
{
this.su_z = (char) (this.data.ll8[this.su_tPos] & 0xff);
this.su_tPos = this.data.tt[this.su_tPos];
if (this.su_rNToGo == 0)
{
this.su_rNToGo = Rand.Rnums(this.su_rTPos) - 1;
if (++this.su_rTPos == 512)
{
this.su_rTPos = 0;
}
}
else
{
this.su_rNToGo--;
}
this.su_j2 = 0;
this.currentState = CState.RAND_PART_C;
if (this.su_rNToGo == 1)
{
this.su_z ^= (char)1;
}
SetupRandPartC();
}
else
{
this.currentState = CState.RAND_PART_A;
SetupRandPartA();
}
}
private void SetupRandPartC()
{
if (this.su_j2 < this.su_z)
{
this.currentChar = this.su_ch2;
this.crc.UpdateCRC((byte)this.su_ch2);
this.su_j2++;
}
else
{
this.currentState = CState.RAND_PART_A;
this.su_i2++;
this.su_count = 0;
SetupRandPartA();
}
}
private void SetupNoRandPartB()
{
if (this.su_ch2 != this.su_chPrev)
{
this.su_count = 1;
SetupNoRandPartA();
}
else if (++this.su_count >= 4)
{
this.su_z = (char) (this.data.ll8[this.su_tPos] & 0xff);
this.su_tPos = this.data.tt[this.su_tPos];
this.su_j2 = 0;
SetupNoRandPartC();
}
else
{
SetupNoRandPartA();
}
}
private void SetupNoRandPartC()
{
if (this.su_j2 < this.su_z)
{
int su_ch2Shadow = this.su_ch2;
this.currentChar = su_ch2Shadow;
this.crc.UpdateCRC((byte)su_ch2Shadow);
this.su_j2++;
this.currentState = CState.NO_RAND_PART_C;
}
else
{
this.su_i2++;
this.su_count = 0;
SetupNoRandPartA();
}
}
private sealed class DecompressionState
{
// (with blockSize 900k)
readonly public bool[] inUse = new bool[256];
readonly public byte[] seqToUnseq = new byte[256]; // 256 byte
readonly public byte[] selector = new byte[BZip2.MaxSelectors]; // 18002 byte
readonly public byte[] selectorMtf = new byte[BZip2.MaxSelectors]; // 18002 byte
/**
* Freq table collected to save a pass over the data during
* decompression.
*/
public readonly int[] unzftab;
public readonly int[][] gLimit;
public readonly int[][] gBase;
public readonly int[][] gPerm;
public readonly int[] gMinlen;
public readonly int[] cftab;
public readonly byte[] getAndMoveToFrontDecode_yy;
public readonly char[][] temp_charArray2d;
public readonly byte[] recvDecodingTables_pos;
// ---------------
// 60798 byte
public int[] tt; // 3600000 byte
public byte[] ll8; // 900000 byte
// ---------------
// 4560782 byte
// ===============
public DecompressionState(int blockSize100k)
{
this.unzftab = new int[256]; // 1024 byte
this.gLimit = BZip2.InitRectangularArray<int>(BZip2.NGroups,BZip2.MaxAlphaSize);
this.gBase = BZip2.InitRectangularArray<int>(BZip2.NGroups,BZip2.MaxAlphaSize);
this.gPerm = BZip2.InitRectangularArray<int>(BZip2.NGroups,BZip2.MaxAlphaSize);
this.gMinlen = new int[BZip2.NGroups]; // 24 byte
this.cftab = new int[257]; // 1028 byte
this.getAndMoveToFrontDecode_yy = new byte[256]; // 512 byte
this.temp_charArray2d = BZip2.InitRectangularArray<char>(BZip2.NGroups,BZip2.MaxAlphaSize);
this.recvDecodingTables_pos = new byte[BZip2.NGroups]; // 6 byte
this.ll8 = new byte[blockSize100k * BZip2.BlockSizeMultiple];
}
/**
* Initializes the tt array.
*
* This method is called when the required length of the array is known.
* I don't initialize it at construction time to avoid unneccessary
* memory allocation when compressing small files.
*/
public int[] initTT(int length)
{
int[] ttShadow = this.tt;
// tt.length should always be >= length, but theoretically
// it can happen, if the compressor mixed small and large
// blocks. Normally only the last block will be smaller
// than others.
if ((ttShadow == null) || (ttShadow.Length < length))
{
this.tt = ttShadow = new int[length];
}
return ttShadow;
}
}
}
// /**
// * Checks if the signature matches what is expected for a bzip2 file.
// *
// * @param signature
// * the bytes to check
// * @param length
// * the number of bytes to check
// * @return true, if this stream is a bzip2 compressed stream, false otherwise
// *
// * @since Apache Commons Compress 1.1
// */
// public static boolean MatchesSig(byte[] signature)
// {
// if ((signature.Length < 3) ||
// (signature[0] != 'B') ||
// (signature[1] != 'Z') ||
// (signature[2] != 'h'))
// return false;
//
// return true;
// }
internal static class BZip2
{
internal static T[][] InitRectangularArray<T>(int d1, int d2)
{
var x = new T[d1][];
for (int i=0; i < d1; i++)
{
x[i] = new T[d2];
}
return x;
}
public static readonly int BlockSizeMultiple = 100000;
public static readonly int MinBlockSize = 1;
public static readonly int MaxBlockSize = 9;
public static readonly int MaxAlphaSize = 258;
public static readonly int MaxCodeLength = 23;
public static readonly char RUNA = (char) 0;
public static readonly char RUNB = (char) 1;
public static readonly int NGroups = 6;
public static readonly int G_SIZE = 50;
public static readonly int N_ITERS = 4;
public static readonly int MaxSelectors = (2 + (900000 / G_SIZE));
public static readonly int NUM_OVERSHOOT_BYTES = 20;
/*
* <p> If you are ever unlucky/improbable enough to get a stack
* overflow whilst sorting, increase the following constant and
* try again. In practice I have never seen the stack go above 27
* elems, so the following limit seems very generous. </p>
*/
internal static readonly int QSORT_STACK_SIZE = 1000;
}
}
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