Mega Code Archive
BZip2 format
<![CDATA[
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
import java.io.IOException;
import java.io.InputStream;
/**
* An input stream that decompresses from the BZip2 format (without the file
* header chars) to be read as any other stream.
*
* @author <a href="mailto:keiron@aftexsw.com">Keiron Liddle</a>
*/
public class CBZip2InputStream
extends InputStream
implements BZip2Constants
{
private static final int START_BLOCK_STATE = 1;
private static final int RAND_PART_A_STATE = 2;
private static final int RAND_PART_B_STATE = 3;
private static final int RAND_PART_C_STATE = 4;
private static final int NO_RAND_PART_A_STATE = 5;
private static final int NO_RAND_PART_B_STATE = 6;
private static final int NO_RAND_PART_C_STATE = 7;
private CRC m_crc = new CRC();
private boolean[] m_inUse = new boolean[ 256 ];
private char[] m_seqToUnseq = new char[ 256 ];
private char[] m_unseqToSeq = new char[ 256 ];
private char[] m_selector = new char[ MAX_SELECTORS ];
private char[] m_selectorMtf = new char[ MAX_SELECTORS ];
/*
* freq table collected to save a pass over the data
* during decompression.
*/
private int[] m_unzftab = new int[ 256 ];
private int[][] m_limit = new int[ N_GROUPS ][ MAX_ALPHA_SIZE ];
private int[][] m_base = new int[ N_GROUPS ][ MAX_ALPHA_SIZE ];
private int[][] m_perm = new int[ N_GROUPS ][ MAX_ALPHA_SIZE ];
private int[] m_minLens = new int[ N_GROUPS ];
private boolean m_streamEnd;
private int m_currentChar = -1;
private int m_currentState = START_BLOCK_STATE;
private int m_rNToGo;
private int m_rTPos;
private int m_tPos;
private int i2;
private int count;
private int chPrev;
private int ch2;
private int j2;
private char z;
private boolean m_blockRandomised;
/*
* always: in the range 0 .. 9.
* The current block size is 100000 * this number.
*/
private int m_blockSize100k;
private int m_bsBuff;
private int m_bsLive;
private InputStream m_input;
private int m_computedBlockCRC;
private int m_computedCombinedCRC;
/*
* index of the last char in the block, so
* the block size == last + 1.
*/
private int m_last;
private char[] m_ll8;
private int m_nInUse;
/*
* index in zptr[] of original string after sorting.
*/
private int m_origPtr;
private int m_storedBlockCRC;
private int m_storedCombinedCRC;
private int[] m_tt;
public CBZip2InputStream( final InputStream input )
{
bsSetStream( input );
initialize();
initBlock();
setupBlock();
}
private static void badBlockHeader()
{
cadvise();
}
private static void blockOverrun()
{
cadvise();
}
private static void cadvise()
{
System.out.println( "CRC Error" );
//throw new CCoruptionError();
}
private static void compressedStreamEOF()
{
cadvise();
}
private static void crcError()
{
cadvise();
}
public int read()
{
if( m_streamEnd )
{
return -1;
}
else
{
int retChar = m_currentChar;
switch( m_currentState )
{
case START_BLOCK_STATE:
break;
case RAND_PART_A_STATE:
break;
case RAND_PART_B_STATE:
setupRandPartB();
break;
case RAND_PART_C_STATE:
setupRandPartC();
break;
case NO_RAND_PART_A_STATE:
break;
case NO_RAND_PART_B_STATE:
setupNoRandPartB();
break;
case NO_RAND_PART_C_STATE:
setupNoRandPartC();
break;
default:
break;
}
return retChar;
}
}
private void setDecompressStructureSizes( int newSize100k )
{
if( !( 0 <= newSize100k && newSize100k <= 9 && 0 <= m_blockSize100k
&& m_blockSize100k <= 9 ) )
{
// throw new IOException("Invalid block size");
}
m_blockSize100k = newSize100k;
if( newSize100k == 0 )
{
return;
}
int n = BASE_BLOCK_SIZE * newSize100k;
m_ll8 = new char[ n ];
m_tt = new int[ n ];
}
private void setupBlock()
{
int[] cftab = new int[ 257 ];
char ch;
cftab[ 0 ] = 0;
for( int i = 1; i <= 256; i++ )
{
cftab[ i ] = m_unzftab[ i - 1 ];
}
for( int i = 1; i <= 256; i++ )
{
cftab[ i ] += cftab[ i - 1 ];
}
for( int i = 0; i <= m_last; i++ )
{
ch = m_ll8[ i ];
m_tt[ cftab[ ch ] ] = i;
cftab[ ch ]++;
}
cftab = null;
m_tPos = m_tt[ m_origPtr ];
count = 0;
i2 = 0;
ch2 = 256;
/*
* not a char and not EOF
*/
if( m_blockRandomised )
{
m_rNToGo = 0;
m_rTPos = 0;
setupRandPartA();
}
else
{
setupNoRandPartA();
}
}
private void setupNoRandPartA()
{
if( i2 <= m_last )
{
chPrev = ch2;
ch2 = m_ll8[ m_tPos ];
m_tPos = m_tt[ m_tPos ];
i2++;
m_currentChar = ch2;
m_currentState = NO_RAND_PART_B_STATE;
m_crc.updateCRC( ch2 );
}
else
{
endBlock();
initBlock();
setupBlock();
}
}
private void setupNoRandPartB()
{
if( ch2 != chPrev )
{
m_currentState = NO_RAND_PART_A_STATE;
count = 1;
setupNoRandPartA();
}
else
{
count++;
if( count >= 4 )
{
z = m_ll8[ m_tPos ];
m_tPos = m_tt[ m_tPos ];
m_currentState = NO_RAND_PART_C_STATE;
j2 = 0;
setupNoRandPartC();
}
else
{
m_currentState = NO_RAND_PART_A_STATE;
setupNoRandPartA();
}
}
}
private void setupNoRandPartC()
{
if( j2 < z )
{
m_currentChar = ch2;
m_crc.updateCRC( ch2 );
j2++;
}
else
{
m_currentState = NO_RAND_PART_A_STATE;
i2++;
count = 0;
setupNoRandPartA();
}
}
private void setupRandPartA()
{
if( i2 <= m_last )
{
chPrev = ch2;
ch2 = m_ll8[ m_tPos ];
m_tPos = m_tt[ m_tPos ];
if( m_rNToGo == 0 )
{
m_rNToGo = RAND_NUMS[ m_rTPos ];
m_rTPos++;
if( m_rTPos == 512 )
{
m_rTPos = 0;
}
}
m_rNToGo--;
ch2 ^= ( ( m_rNToGo == 1 ) ? 1 : 0 );
i2++;
m_currentChar = ch2;
m_currentState = RAND_PART_B_STATE;
m_crc.updateCRC( ch2 );
}
else
{
endBlock();
initBlock();
setupBlock();
}
}
private void setupRandPartB()
{
if( ch2 != chPrev )
{
m_currentState = RAND_PART_A_STATE;
count = 1;
setupRandPartA();
}
else
{
count++;
if( count >= 4 )
{
z = m_ll8[ m_tPos ];
m_tPos = m_tt[ m_tPos ];
if( m_rNToGo == 0 )
{
m_rNToGo = RAND_NUMS[ m_rTPos ];
m_rTPos++;
if( m_rTPos == 512 )
{
m_rTPos = 0;
}
}
m_rNToGo--;
z ^= ( ( m_rNToGo == 1 ) ? 1 : 0 );
j2 = 0;
m_currentState = RAND_PART_C_STATE;
setupRandPartC();
}
else
{
m_currentState = RAND_PART_A_STATE;
setupRandPartA();
}
}
}
private void setupRandPartC()
{
if( j2 < z )
{
m_currentChar = ch2;
m_crc.updateCRC( ch2 );
j2++;
}
else
{
m_currentState = RAND_PART_A_STATE;
i2++;
count = 0;
setupRandPartA();
}
}
private void getAndMoveToFrontDecode()
{
int nextSym;
int limitLast = BASE_BLOCK_SIZE * m_blockSize100k;
m_origPtr = readVariableSizedInt( 24 );
recvDecodingTables();
int EOB = m_nInUse + 1;
int groupNo = -1;
int groupPos = 0;
/*
* 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 = 0; i <= 255; i++ )
{
m_unzftab[ i ] = 0;
}
final char[] yy = new char[ 256 ];
for( int i = 0; i <= 255; i++ )
{
yy[ i ] = (char)i;
}
m_last = -1;
int zt;
int zn;
int zvec;
int zj;
groupNo++;
groupPos = G_SIZE - 1;
zt = m_selector[ groupNo ];
zn = m_minLens[ zt ];
zvec = bsR( zn );
while( zvec > m_limit[ zt ][ zn ] )
{
zn++;
while( m_bsLive < 1 )
{
int zzi;
try
{
zzi = m_input.read();
}
catch( IOException e )
{
compressedStreamEOF();
break;
}
if( zzi == -1 )
{
compressedStreamEOF();
break;
}
m_bsBuff = ( m_bsBuff << 8 ) | ( zzi & 0xff );
m_bsLive += 8;
}
zj = ( m_bsBuff >> ( m_bsLive - 1 ) ) & 1;
m_bsLive--;
zvec = ( zvec << 1 ) | zj;
}
nextSym = m_perm[ zt ][ zvec - m_base[ zt ][ zn ] ];
while( true )
{
if( nextSym == EOB )
{
break;
}
if( nextSym == RUNA || nextSym == RUNB )
{
char ch;
int s = -1;
int N = 1;
do
{
if( nextSym == RUNA )
{
s = s + ( 0 + 1 ) * N;
}
else// if( nextSym == RUNB )
{
s = s + ( 1 + 1 ) * N;
}
N = N * 2;
if( groupPos == 0 )
{
groupNo++;
groupPos = G_SIZE;
}
groupPos--;
zt = m_selector[ groupNo ];
zn = m_minLens[ zt ];
zvec = bsR( zn );
while( zvec > m_limit[ zt ][ zn ] )
{
zn++;
while( m_bsLive < 1 )
{
int zzi;
char thech = 0;
try
{
thech = (char)m_input.read();
}
catch( IOException e )
{
compressedStreamEOF();
}
if( thech == -1 )
{
compressedStreamEOF();
}
zzi = thech;
m_bsBuff = ( m_bsBuff << 8 ) | ( zzi & 0xff );
m_bsLive += 8;
}
zj = ( m_bsBuff >> ( m_bsLive - 1 ) ) & 1;
m_bsLive--;
zvec = ( zvec << 1 ) | zj;
}
nextSym = m_perm[ zt ][ zvec - m_base[ zt ][ zn ] ];
} while( nextSym == RUNA || nextSym == RUNB );
s++;
ch = m_seqToUnseq[ yy[ 0 ] ];
m_unzftab[ ch ] += s;
while( s > 0 )
{
m_last++;
m_ll8[ m_last ] = ch;
s--;
}
if( m_last >= limitLast )
{
blockOverrun();
}
continue;
}
else
{
char tmp;
m_last++;
if( m_last >= limitLast )
{
blockOverrun();
}
tmp = yy[ nextSym - 1 ];
m_unzftab[ m_seqToUnseq[ tmp ] ]++;
m_ll8[ m_last ] = m_seqToUnseq[ tmp ];
/*
* This loop is hammered during decompression,
* hence the unrolling.
* for (j = nextSym-1; j > 0; j--) yy[j] = yy[j-1];
*/
int j = nextSym - 1;
for( ; j > 3; j -= 4 )
{
yy[ j ] = yy[ j - 1 ];
yy[ j - 1 ] = yy[ j - 2 ];
yy[ j - 2 ] = yy[ j - 3 ];
yy[ j - 3 ] = yy[ j - 4 ];
}
for( ; j > 0; j-- )
{
yy[ j ] = yy[ j - 1 ];
}
yy[ 0 ] = tmp;
if( groupPos == 0 )
{
groupNo++;
groupPos = G_SIZE;
}
groupPos--;
zt = m_selector[ groupNo ];
zn = m_minLens[ zt ];
zvec = bsR( zn );
while( zvec > m_limit[ zt ][ zn ] )
{
zn++;
while( m_bsLive < 1 )
{
char ch = 0;
try
{
ch = (char)m_input.read();
}
catch( IOException e )
{
compressedStreamEOF();
}
m_bsBuff = ( m_bsBuff << 8 ) | ( ch & 0xff );
m_bsLive += 8;
}
zj = ( m_bsBuff >> ( m_bsLive - 1 ) ) & 1;
m_bsLive--;
zvec = ( zvec << 1 ) | zj;
}
nextSym = m_perm[ zt ][ zvec - m_base[ zt ][ zn ] ];
continue;
}
}
}
private void bsFinishedWithStream()
{
m_input = null;
}
private int readVariableSizedInt( final int numBits )
{
return bsR( numBits );
}
private char readUnsignedChar()
{
return (char)bsR( 8 );
}
private int readInt()
{
int u = 0;
u = ( u << 8 ) | bsR( 8 );
u = ( u << 8 ) | bsR( 8 );
u = ( u << 8 ) | bsR( 8 );
u = ( u << 8 ) | bsR( 8 );
return u;
}
private int bsR( final int n )
{
while( m_bsLive < n )
{
char ch = 0;
try
{
ch = (char)m_input.read();
}
catch( final IOException ioe )
{
compressedStreamEOF();
}
if( ch == -1 )
{
compressedStreamEOF();
}
m_bsBuff = ( m_bsBuff << 8 ) | ( ch & 0xff );
m_bsLive += 8;
}
final int result = ( m_bsBuff >> ( m_bsLive - n ) ) & ( ( 1 << n ) - 1 );
m_bsLive -= n;
return result;
}
private void bsSetStream( final InputStream input )
{
m_input = input;
m_bsLive = 0;
m_bsBuff = 0;
}
private void complete()
{
m_storedCombinedCRC = readInt();
if( m_storedCombinedCRC != m_computedCombinedCRC )
{
crcError();
}
bsFinishedWithStream();
m_streamEnd = true;
}
private void endBlock()
{
m_computedBlockCRC = m_crc.getFinalCRC();
/*
* A bad CRC is considered a fatal error.
*/
if( m_storedBlockCRC != m_computedBlockCRC )
{
crcError();
}
m_computedCombinedCRC = ( m_computedCombinedCRC << 1 )
| ( m_computedCombinedCRC >>> 31 );
m_computedCombinedCRC ^= m_computedBlockCRC;
}
private void hbCreateDecodeTables( final int[] limit,
final int[] base,
final int[] perm,
final char[] length,
final int minLen,
final int maxLen,
final int alphaSize )
{
int pp = 0;
for( int i = minLen; i <= maxLen; i++ )
{
for( int j = 0; j < alphaSize; j++ )
{
if( length[ j ] == i )
{
perm[ pp ] = j;
pp++;
}
}
}
for( int i = 0; i < MAX_CODE_LEN; i++ )
{
base[ i ] = 0;
}
for( int i = 0; i < alphaSize; i++ )
{
base[ length[ i ] + 1 ]++;
}
for( int i = 1; i < MAX_CODE_LEN; i++ )
{
base[ i ] += base[ i - 1 ];
}
for( int i = 0; i < MAX_CODE_LEN; i++ )
{
limit[ i ] = 0;
}
int vec = 0;
for( int i = minLen; i <= maxLen; i++ )
{
vec += ( base[ i + 1 ] - base[ i ] );
limit[ i ] = vec - 1;
vec <<= 1;
}
for( int i = minLen + 1; i <= maxLen; i++ )
{
base[ i ] = ( ( limit[ i - 1 ] + 1 ) << 1 ) - base[ i ];
}
}
private void initBlock()
{
final char magic1 = readUnsignedChar();
final char magic2 = readUnsignedChar();
final char magic3 = readUnsignedChar();
final char magic4 = readUnsignedChar();
final char magic5 = readUnsignedChar();
final char magic6 = readUnsignedChar();
if( magic1 == 0x17 && magic2 == 0x72 && magic3 == 0x45 &&
magic4 == 0x38 && magic5 == 0x50 && magic6 == 0x90 )
{
complete();
return;
}
if( magic1 != 0x31 || magic2 != 0x41 || magic3 != 0x59 ||
magic4 != 0x26 || magic5 != 0x53 || magic6 != 0x59 )
{
badBlockHeader();
m_streamEnd = true;
return;
}
m_storedBlockCRC = readInt();
if( bsR( 1 ) == 1 )
{
m_blockRandomised = true;
}
else
{
m_blockRandomised = false;
}
// currBlockNo++;
getAndMoveToFrontDecode();
m_crc.initialiseCRC();
m_currentState = START_BLOCK_STATE;
}
private void initialize()
{
final char magic3 = readUnsignedChar();
final char magic4 = readUnsignedChar();
if( magic3 != 'h' || magic4 < '1' || magic4 > '9' )
{
bsFinishedWithStream();
m_streamEnd = true;
return;
}
setDecompressStructureSizes( magic4 - '0' );
m_computedCombinedCRC = 0;
}
private void makeMaps()
{
m_nInUse = 0;
for( int i = 0; i < 256; i++ )
{
if( m_inUse[ i ] )
{
m_seqToUnseq[ m_nInUse ] = (char)i;
m_unseqToSeq[ i ] = (char)m_nInUse;
m_nInUse++;
}
}
}
private void recvDecodingTables()
{
buildInUseTable();
makeMaps();
final int alphaSize = m_nInUse + 2;
/*
* Now the selectors
*/
final int groupCount = bsR( 3 );
final int selectorCount = bsR( 15 );
for( int i = 0; i < selectorCount; i++ )
{
int run = 0;
while( bsR( 1 ) == 1 )
{
run++;
}
m_selectorMtf[ i ] = (char)run;
}
/*
* Undo the MTF values for the selectors.
*/
final char[] pos = new char[ N_GROUPS ];
for( char v = 0; v < groupCount; v++ )
{
pos[ v ] = v;
}
for( int i = 0; i < selectorCount; i++ )
{
int v = m_selectorMtf[ i ];
final char tmp = pos[ v ];
while( v > 0 )
{
pos[ v ] = pos[ v - 1 ];
v--;
}
pos[ 0 ] = tmp;
m_selector[ i ] = tmp;
}
final char[][] len = new char[ N_GROUPS ][ MAX_ALPHA_SIZE ];
/*
* Now the coding tables
*/
for( int i = 0; i < groupCount; i++ )
{
int curr = bsR( 5 );
for( int j = 0; j < alphaSize; j++ )
{
while( bsR( 1 ) == 1 )
{
if( bsR( 1 ) == 0 )
{
curr++;
}
else
{
curr--;
}
}
len[ i ][ j ] = (char)curr;
}
}
/*
* Create the Huffman decoding tables
*/
for( int k = 0; k < groupCount; k++ )
{
int minLen = 32;
int maxLen = 0;
for( int i = 0; i < alphaSize; i++ )
{
if( len[ k ][ i ] > maxLen )
{
maxLen = len[ k ][ i ];
}
if( len[ k ][ i ] < minLen )
{
minLen = len[ k ][ i ];
}
}
hbCreateDecodeTables( m_limit[ k ], m_base[ k ], m_perm[ k ], len[ k ], minLen,
maxLen, alphaSize );
m_minLens[ k ] = minLen;
}
}
private void buildInUseTable()
{
final boolean[] inUse16 = new boolean[ 16 ];
/*
* Receive the mapping table
*/
for( int i = 0; i < 16; i++ )
{
if( bsR( 1 ) == 1 )
{
inUse16[ i ] = true;
}
else
{
inUse16[ i ] = false;
}
}
for( int i = 0; i < 256; i++ )
{
m_inUse[ i ] = false;
}
for( int i = 0; i < 16; i++ )
{
if( inUse16[ i ] )
{
for( int j = 0; j < 16; j++ )
{
if( bsR( 1 ) == 1 )
{
m_inUse[ i * 16 + j ] = true;
}
}
}
}
}
}
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
/**
* Base class for both the compress and decompress classes. Holds common arrays,
* and static data.
*
* @author <a href="mailto:keiron@aftexsw.com">Keiron Liddle</a>
*/
interface BZip2Constants
{
int BASE_BLOCK_SIZE = 100000;
int MAX_ALPHA_SIZE = 258;
int MAX_CODE_LEN = 23;
int RUNA = 0;
int RUNB = 1;
int N_GROUPS = 6;
int G_SIZE = 50;
int N_ITERS = 4;
int MAX_SELECTORS = ( 2 + ( 900000 / G_SIZE ) );
int NUM_OVERSHOOT_BYTES = 20;
int[] RAND_NUMS = new int[]
{
619, 720, 127, 481, 931, 816, 813, 233, 566, 247,
985, 724, 205, 454, 863, 491, 741, 242, 949, 214,
733, 859, 335, 708, 621, 574, 73, 654, 730, 472,
419, 436, 278, 496, 867, 210, 399, 680, 480, 51,
878, 465, 811, 169, 869, 675, 611, 697, 867, 561,
862, 687, 507, 283, 482, 129, 807, 591, 733, 623,
150, 238, 59, 379, 684, 877, 625, 169, 643, 105,
170, 607, 520, 932, 727, 476, 693, 425, 174, 647,
73, 122, 335, 530, 442, 853, 695, 249, 445, 515,
909, 545, 703, 919, 874, 474, 882, 500, 594, 612,
641, 801, 220, 162, 819, 984, 589, 513, 495, 799,
161, 604, 958, 533, 221, 400, 386, 867, 600, 782,
382, 596, 414, 171, 516, 375, 682, 485, 911, 276,
98, 553, 163, 354, 666, 933, 424, 341, 533, 870,
227, 730, 475, 186, 263, 647, 537, 686, 600, 224,
469, 68, 770, 919, 190, 373, 294, 822, 808, 206,
184, 943, 795, 384, 383, 461, 404, 758, 839, 887,
715, 67, 618, 276, 204, 918, 873, 777, 604, 560,
951, 160, 578, 722, 79, 804, 96, 409, 713, 940,
652, 934, 970, 447, 318, 353, 859, 672, 112, 785,
645, 863, 803, 350, 139, 93, 354, 99, 820, 908,
609, 772, 154, 274, 580, 184, 79, 626, 630, 742,
653, 282, 762, 623, 680, 81, 927, 626, 789, 125,
411, 521, 938, 300, 821, 78, 343, 175, 128, 250,
170, 774, 972, 275, 999, 639, 495, 78, 352, 126,
857, 956, 358, 619, 580, 124, 737, 594, 701, 612,
669, 112, 134, 694, 363, 992, 809, 743, 168, 974,
944, 375, 748, 52, 600, 747, 642, 182, 862, 81,
344, 805, 988, 739, 511, 655, 814, 334, 249, 515,
897, 955, 664, 981, 649, 113, 974, 459, 893, 228,
433, 837, 553, 268, 926, 240, 102, 654, 459, 51,
686, 754, 806, 760, 493, 403, 415, 394, 687, 700,
946, 670, 656, 610, 738, 392, 760, 799, 887, 653,
978, 321, 576, 617, 626, 502, 894, 679, 243, 440,
680, 879, 194, 572, 640, 724, 926, 56, 204, 700,
707, 151, 457, 449, 797, 195, 791, 558, 945, 679,
297, 59, 87, 824, 713, 663, 412, 693, 342, 606,
134, 108, 571, 364, 631, 212, 174, 643, 304, 329,
343, 97, 430, 751, 497, 314, 983, 374, 822, 928,
140, 206, 73, 263, 980, 736, 876, 478, 430, 305,
170, 514, 364, 692, 829, 82, 855, 953, 676, 246,
369, 970, 294, 750, 807, 827, 150, 790, 288, 923,
804, 378, 215, 828, 592, 281, 565, 555, 710, 82,
896, 831, 547, 261, 524, 462, 293, 465, 502, 56,
661, 821, 976, 991, 658, 869, 905, 758, 745, 193,
768, 550, 608, 933, 378, 286, 215, 979, 792, 961,
61, 688, 793, 644, 986, 403, 106, 366, 905, 644,
372, 567, 466, 434, 645, 210, 389, 550, 919, 135,
780, 773, 635, 389, 707, 100, 626, 958, 165, 504,
920, 176, 193, 713, 857, 265, 203, 50, 668, 108,
645, 990, 626, 197, 510, 357, 358, 850, 858, 364,
936, 638
};
}
/**
* A simple class the hold and calculate the CRC for sanity checking of the
* data.
*
* @author <a href="mailto:keiron@aftexsw.com">Keiron Liddle</a>
*/
class CRC
{
private static int[] CRC32_TABLE = new int[]
{
0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
};
private int m_globalCrc;
protected CRC()
{
initialiseCRC();
}
int getFinalCRC()
{
return ~m_globalCrc;
}
void initialiseCRC()
{
m_globalCrc = 0xffffffff;
}
void updateCRC( final int inCh )
{
int temp = ( m_globalCrc >> 24 ) ^ inCh;
if( temp < 0 )
{
temp = 256 + temp;
}
m_globalCrc = ( m_globalCrc << 8 ) ^ CRC32_TABLE[ temp ];
}
}
]]>