-/*~~ ~~Small bzip2 deflate implementation, by Rob Landley (rob@landley.net).

+/* Small bzip2 deflate implementation, 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.

+ 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.

- This code is licensed under the LGPLv2:

- LGPL (http://www.gnu.org/copyleft/lgpl.html

+ This code is licensed under the LGPLv2:

+ LGPL (http://www.gnu.org/copyleft/lgpl.html

-~~ ~~Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org).

+ Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org).

- More efficient reading of huffman codes, a streamlined read_bunzip()

- function, and various other tweaks. In (limited) tests, approximately

- 20% faster than bzcat on x86 and about 10% faster on arm.

+ More efficient reading of huffman codes, a streamlined read_bunzip()

+ function, and various other tweaks. In (limited) tests, approximately

+ 20% faster than bzcat on x86 and about 10% faster on arm.

- Note that about 2/3 of the time is spent in read_unzip() reversing

- the Burrows-Wheeler transformation. Much of that time is delay

- resulting from cache misses.

+ Note that about 2/3 of the time is spent in read_unzip() reversing

+ the Burrows-Wheeler transformation. Much of that time is delay

+ resulting from cache misses.

- I would ask that anyone benefiting from this work, especially those

- using it in commercial products, consider making a donation to my local

- non-profit hospice organization (see www.hospiceacadiana.com) in the

+ I would ask that anyone benefiting from this work, especially those

+ using it in commercial products, consider making a donation to my local

+ non-profit hospice organization (see www.hospiceacadiana.com) in the

name of the woman I loved, Toni W. Hagan, who passed away Feb. 12, 2003.

/* Constants for huffman coding */

-#define GROUP_SIZE 50 /* 64 would have been more efficient */

-#define MAX_HUFCODE_BITS 20 /* Longest huffman code allowed */

-#define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */

+#define GROUP_SIZE 50 /* 64 would have been more efficient */

+#define MAX_HUFCODE_BITS 20 /* Longest huffman code allowed */

+#define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */

/* Status return values */

-#define RETVAL_LAST_BLOCK (-1)

-#define RETVAL_NOT_BZIP_DATA (-2)

-#define RETVAL_UNEXPECTED_INPUT_EOF (-3)

-#define RETVAL_UNEXPECTED_OUTPUT_EOF (-4)

-#define RETVAL_DATA_ERROR (-5)

-#define RETVAL_OUT_OF_MEMORY (-6)

-#define RETVAL_OBSOLETE_INPUT (-7)

+#define RETVAL_LAST_BLOCK (-1)

+#define RETVAL_NOT_BZIP_DATA (-2)

+#define RETVAL_UNEXPECTED_INPUT_EOF (-3)

+#define RETVAL_UNEXPECTED_OUTPUT_EOF (-4)

+#define RETVAL_DATA_ERROR (-5)

+#define RETVAL_OUT_OF_MEMORY (-6)

+#define RETVAL_OBSOLETE_INPUT (-7)

#define RETVAL_END_OF_BLOCK (-8)

/* Other housekeeping constants */

/* This is what we know about each huffman coding group */

- /* We have an extra slot at the end of limit[] for a sentinal value. */

- int limit[MAX_HUFCODE_BITS+1],base[MAX_HUFCODE_BITS],permute[MAX_SYMBOLS];

+ /* We have an extra slot at the end of limit[] for a sentinal value. */

+ int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS];

/* Structure holding all the housekeeping data, including IO buffers and

memory that persists between calls to bunzip */

- /* State for interrupting output loop */

- int writeCopies,writePos,writeRunCountdown,writeCount,writeCurrent;

- /* I/O tracking data (file handles, buffers, positions, etc.) */

- int in_fd,out_fd,inbufCount,inbufPos /*,outbufPos*/;

- unsigned char *inbuf /*,*outbuf*/;

- unsigned int inbufBitCount, inbufBits;

- /* The CRC values stored in the block header and calculated from the data */

- unsigned int crc32Table[256],headerCRC, totalCRC, writeCRC;

- /* Intermediate buffer and its size (in bytes) */

- unsigned int *dbuf, dbufSize;

- /* These things are a bit too big to go on the stack */

- unsigned char selectors[32768]; /* nSelectors=15 bits */

- struct group_data groups[MAX_GROUPS]; /* huffman coding tables */

- /* For I/O error handling */

+ /* State for interrupting output loop */

+ int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent;

+ /* I/O tracking data (file handles, buffers, positions, etc.) */

+ int in_fd, out_fd, inbufCount, inbufPos /*,outbufPos*/;

+ // james@jamestaylor.org: track relative position in input so we don't need tell

+ unsigned char *inbuf /*,*outbuf*/;

+ unsigned int inbufBitCount, inbufBits;

+ /* The CRC values stored in the block header and calculated from the data */

+ unsigned int crc32Table[256], headerCRC, totalCRC, writeCRC;

+ /* Intermediate buffer and its size (in bytes) */

+ unsigned int *dbuf, dbufSize;

+ /* These things are a bit too big to go on the stack */

+ unsigned char selectors[32768]; /* nSelectors=15 bits */

+ struct group_data groups[MAX_GROUPS]; /* huffman coding tables */

+ /* For I/O error handling */

/* Return the next nnn bits of input. All reads from the compressed input

are done through this function. All reads are big endian */

-unsigned int get_bits(bunzip_data *bd, char bits_wanted)

+unsigned int get_bits( bunzip_data *bd, char bits_wanted )

- /* If we need to get more data from the byte buffer, do so. (Loop getting

- one byte at a time to enforce endianness and avoid unaligned access.) */

- while (bd->inbufBitCount<bits_wanted) {

- /* If we need to read more data from file into byte buffer, do so */

- if(bd->inbufPos==bd->inbufCount) {

- if((bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE)) <= 0)

- longjmp(bd->jmpbuf,RETVAL_UNEXPECTED_INPUT_EOF);

- /* Avoid 32-bit overflow (dump bit buffer to top of output) */

- if(bd->inbufBitCount>=24) {

- bits=bd->inbufBits&((1<<bd->inbufBitCount)-1);

- bits_wanted-=bd->inbufBitCount;

- /* Grab next 8 bits of input from buffer. */

- bd->inbufBits=(bd->inbufBits<<8)|bd->inbuf[bd->inbufPos++];

- bd->inbufBitCount-=bits_wanted;

- bits|=(bd->inbufBits>>bd->inbufBitCount)&((1<<bits_wanted)-1);

+ /* If we need to get more data from the byte buffer, do so. (Loop getting

+ one byte at a time to enforce endianness and avoid unaligned access.) */

+ while ( bd->inbufBitCount < bits_wanted )

+ /* If we need to read more data from file into byte buffer, do so */

+ if ( bd->inbufPos == bd->inbufCount )

+ if ( ( bd->inbufCount = read( bd->in_fd, bd->inbuf, IOBUF_SIZE ) ) <= 0 )

+ longjmp( bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF );

+ // james@jamestaylor.org: track position

+ bd->position += bd->inbufCount;

+ /* Avoid 32-bit overflow (dump bit buffer to top of output) */

+ if ( bd->inbufBitCount >= 24 )

+ bits = bd->inbufBits & ( ( 1 << bd->inbufBitCount ) - 1 );

+ bits_wanted -= bd->inbufBitCount;

+ /* Grab next 8 bits of input from buffer. */

+ bd->inbufBits = ( bd->inbufBits << 8 ) | bd->inbuf[bd->inbufPos++];

+ bd->inbufBitCount += 8;

+ bd->inbufBitCount -= bits_wanted;

+ bits |= ( bd->inbufBits >> bd->inbufBitCount ) & ( ( 1 << bits_wanted ) - 1 );

/* Unpacks the next block and sets up for the inverse burrows-wheeler step. */

-int get_next_block(bunzip_data *bd)

+int get_next_block( bunzip_data *bd )

- struct group_data *hufGroup;

- int dbufCount,nextSym,dbufSize,groupCount,*base,*limit,selector,

- i,j,k,t,runPos,symCount,symTotal,nSelectors,byteCount[256];

- unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;

- unsigned int *dbuf,origPtr;

+ struct group_data *hufGroup;

+ int dbufCount, nextSym, dbufSize, groupCount, *base, *limit, selector,

+ i, j, k, t, runPos, symCount, symTotal, nSelectors, byteCount[256];

+ unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;

+ unsigned int *dbuf, origPtr;

- selectors=bd->selectors;

- /* Reset longjmp I/O error handling */

- /* Read in header signature and CRC, then validate signature.

- (last block signature means CRC is for whole file, return now) */

- bd->headerCRC=get_bits(bd,32);

- if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK;

- if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA;

- /* We can add support for blockRandomised if anybody complains. There was

- some code for this in busybox 1.0.0-pre3, but nobody ever noticed that

- it didn't actually work. */

- if(get_bits(bd,1)) return RETVAL_OBSOLETE_INPUT;

- if((origPtr=get_bits(bd,24)) > dbufSize) return RETVAL_DATA_ERROR;

- /* mapping table: if some byte values are never used (encoding things

- like ascii text), the compression code removes the gaps to have fewer

- symbols to deal with, and writes a sparse bitfield indicating which

- values were present. We make a translation table to convert the symbols

- back to the corresponding bytes. */

- if(k&(1<<(15-j))) symToByte[symTotal++]=(16*i)+j;

- /* How many different huffman coding groups does this block use? */

- groupCount=get_bits(bd,3);

- if (groupCount<2 || groupCount>MAX_GROUPS) return RETVAL_DATA_ERROR;

- /* nSelectors: Every GROUP_SIZE many symbols we select a new huffman coding

- group. Read in the group selector list, which is stored as MTF encoded

- bit runs. (MTF=Move To Front, as each value is used it's moved to the

- if(!(nSelectors=get_bits(bd, 15))) return RETVAL_DATA_ERROR;

- for(i=0; i<groupCount; i++) mtfSymbol[i] = i;

- for(i=0; i<nSelectors; i++) {

- for(j=0;get_bits(bd,1);j++) if (j>=groupCount) return RETVAL_DATA_ERROR;

- /* Decode MTF to get the next selector */

- for(;j;j--) mtfSymbol[j] = mtfSymbol[j-1];

- mtfSymbol[0]=selectors[i]=uc;

- /* Read the huffman coding tables for each group, which code for symTotal

- literal symbols, plus two run symbols (RUNA, RUNB) */

- for (j=0; j<groupCount; j++) {

- unsigned char length[MAX_SYMBOLS],temp[MAX_HUFCODE_BITS+1];

- int minLen, maxLen, pp;

- /* Read huffman code lengths for each symbol. They're stored in

- a way similar to mtf; record a starting value for the first symbol,

- and an offset from the previous value for everys symbol after that.

- (Subtracting 1 before the loop and then adding it back at the end is

- an optimization that makes the test inside the loop simpler: symbol

- length 0 becomes negative, so an unsigned inequality catches it.) */

- for (i = 0; i < symCount; i++) {

- if (((unsigned)t) > (MAX_HUFCODE_BITS-1))

- return RETVAL_DATA_ERROR;

- /* If first bit is 0, stop. Else second bit indicates whether

- to increment or decrement the value. Optimization: grab 2

- bits and unget the second if the first was 0. */

- /* Add one if second bit 1, else subtract 1. Avoids if/else */

- /* Correct for the initial -1, to get the final symbol length */

- /* Find largest and smallest lengths in this group */

- minLen=maxLen=length[0];

- for(i = 1; i < symCount; i++) {

- if(length[i] > maxLen) maxLen = length[i];

- else if(length[i] < minLen) minLen = length[i];

- /* Calculate permute[], base[], and limit[] tables from length[].

- * permute[] is the lookup table for converting huffman coded symbols

- * into decoded symbols. base[] is the amount to subtract from the

- * value of a huffman symbol of a given length when using permute[].

- * limit[] indicates the largest numerical value a symbol with a given

- * number of bits can have. This is how the huffman codes can vary in

- * length: each code with a value>limit[length] needs another bit.

- hufGroup->minLen = minLen;

- hufGroup->maxLen = maxLen;

- /* Note that minLen can't be smaller than 1, so we adjust the base

- and limit array pointers so we're not always wasting the first

- entry. We do this again when using them (during symbol decoding).*/

- limit=hufGroup->limit-1;

- /* Calculate permute[]. Concurently, initialize temp[] and limit[]. */

- for(i=minLen;i<=maxLen;i++) {

- for(t=0;t<symCount;t++)

- if(length[t]==i) hufGroup->permute[pp++] = t;

- /* Count symbols coded for at each bit length */

- for (i=0;i<symCount;i++) temp[length[i]]++;

- /* Calculate limit[] (the largest symbol-coding value at each bit

- * length, which is (previous limit<<1)+symbols at this level), and

- * base[] (number of symbols to ignore at each bit length, which is

- * limit minus the cumulative count of symbols coded for already). */

- for (i=minLen; i<maxLen; i++) {

- /* We read the largest possible symbol size and then unget bits

- after determining how many we need, and those extra bits could

- be set to anything. (They're noise from future symbols.) At

- each level we're really only interested in the first few bits,

- so here we set all the trailing to-be-ignored bits to 1 so they

- don't affect the value>limit[length] comparison. */

- limit[i]= (pp << (maxLen - i)) - 1;

- base[i+1]=pp-(t+=temp[i]);

- limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */

- limit[maxLen]=pp+temp[maxLen]-1;

- /* We've finished reading and digesting the block header. Now read this

- block's huffman coded symbols from the file and undo the huffman coding

- and run length encoding, saving the result into dbuf[dbufCount++]=uc */

+ dbufSize = bd->dbufSize;

+ selectors = bd->selectors;

+ /* Reset longjmp I/O error handling */

+ i = setjmp( bd->jmpbuf );

+ /* Read in header signature and CRC, then validate signature.

+ (last block signature means CRC is for whole file, return now) */

+ i = get_bits( bd, 24 );

+ j = get_bits( bd, 24 );

+ bd->headerCRC = get_bits( bd, 32 );

+ if ( ( i == 0x177245 ) && ( j == 0x385090 ) ) return RETVAL_LAST_BLOCK;

+ if ( ( i != 0x314159 ) || ( j != 0x265359 ) ) return RETVAL_NOT_BZIP_DATA;

+ /* We can add support for blockRandomised if anybody complains. There was

+ some code for this in busybox 1.0.0-pre3, but nobody ever noticed that

+ it didn't actually work. */

+ if ( get_bits( bd, 1 ) ) return RETVAL_OBSOLETE_INPUT;

+ if ( ( origPtr = get_bits( bd, 24 ) ) > dbufSize ) return RETVAL_DATA_ERROR;

+ /* mapping table: if some byte values are never used (encoding things

+ like ascii text), the compression code removes the gaps to have fewer

+ symbols to deal with, and writes a sparse bitfield indicating which

+ values were present. We make a translation table to convert the symbols

+ back to the corresponding bytes. */

+ t = get_bits( bd, 16 );

+ for ( i = 0;i < 16;i++ )

+ if ( t&( 1 << ( 15 - i ) ) )

+ k = get_bits( bd, 16 );

+ for ( j = 0;j < 16;j++ )

+ if ( k&( 1 << ( 15 - j ) ) ) symToByte[symTotal++] = ( 16 * i ) + j;

+ /* How many different huffman coding groups does this block use? */

+ groupCount = get_bits( bd, 3 );

+ if ( groupCount < 2 || groupCount > MAX_GROUPS ) return RETVAL_DATA_ERROR;

+ /* nSelectors: Every GROUP_SIZE many symbols we select a new huffman coding

+ group. Read in the group selector list, which is stored as MTF encoded

+ bit runs. (MTF=Move To Front, as each value is used it's moved to the

+ if ( !( nSelectors = get_bits( bd, 15 ) ) ) return RETVAL_DATA_ERROR;

+ for ( i = 0; i < groupCount; i++ ) mtfSymbol[i] = i;

+ for ( i = 0; i < nSelectors; i++ )

+ for ( j = 0;get_bits( bd, 1 );j++ ) if ( j >= groupCount ) return RETVAL_DATA_ERROR;

+ /* Decode MTF to get the next selector */

+ for ( ;j;j-- ) mtfSymbol[j] = mtfSymbol[j-1];

+ mtfSymbol[0] = selectors[i] = uc;

+ /* Read the huffman coding tables for each group, which code for symTotal

+ literal symbols, plus two run symbols (RUNA, RUNB) */

+ symCount = symTotal + 2;

+ for ( j = 0; j < groupCount; j++ )

+ unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1];

+ int minLen, maxLen, pp;

+ /* Read huffman code lengths for each symbol. They're stored in

+ a way similar to mtf; record a starting value for the first symbol,

+ and an offset from the previous value for everys symbol after that.

+ (Subtracting 1 before the loop and then adding it back at the end is

+ an optimization that makes the test inside the loop simpler: symbol

+ length 0 becomes negative, so an unsigned inequality catches it.) */

+ t = get_bits( bd, 5 ) - 1;

+ for ( i = 0; i < symCount; i++ )

+ if ( ( ( unsigned )t ) > ( MAX_HUFCODE_BITS - 1 ) )

+ return RETVAL_DATA_ERROR;

+ /* If first bit is 0, stop. Else second bit indicates whether

+ to increment or decrement the value. Optimization: grab 2

+ bits and unget the second if the first was 0. */

+ /* Add one if second bit 1, else subtract 1. Avoids if/else */

+ t += ( ( ( k + 1 ) & 2 ) - 1 );

+ /* Correct for the initial -1, to get the final symbol length */

+ /* Find largest and smallest lengths in this group */

+ minLen = maxLen = length[0];

+ for ( i = 1; i < symCount; i++ )

+ if ( length[i] > maxLen ) maxLen = length[i];

+ else if ( length[i] < minLen ) minLen = length[i];

+ /* Calculate permute[], base[], and limit[] tables from length[].

+ * permute[] is the lookup table for converting huffman coded symbols

+ * into decoded symbols. base[] is the amount to subtract from the

+ * value of a huffman symbol of a given length when using permute[].

+ * limit[] indicates the largest numerical value a symbol with a given

+ * number of bits can have. This is how the huffman codes can vary in

+ * length: each code with a value>limit[length] needs another bit.

+ hufGroup = bd->groups + j;

+ hufGroup->minLen = minLen;

+ hufGroup->maxLen = maxLen;

+ /* Note that minLen can't be smaller than 1, so we adjust the base

+ and limit array pointers so we're not always wasting the first

+ entry. We do this again when using them (during symbol decoding).*/

+ base = hufGroup->base - 1;

+ limit = hufGroup->limit - 1;

+ /* Calculate permute[]. Concurently, initialize temp[] and limit[]. */

+ for ( i = minLen;i <= maxLen;i++ )

+ temp[i] = limit[i] = 0;

+ for ( t = 0;t < symCount;t++ )

+ if ( length[t] == i ) hufGroup->permute[pp++] = t;

+ /* Count symbols coded for at each bit length */

+ for ( i = 0;i < symCount;i++ ) temp[length[i]]++;

+ /* Calculate limit[] (the largest symbol-coding value at each bit

+ * length, which is (previous limit<<1)+symbols at this level), and

+ * base[] (number of symbols to ignore at each bit length, which is

+ * limit minus the cumulative count of symbols coded for already). */

+ for ( i = minLen; i < maxLen; i++ )

+ /* We read the largest possible symbol size and then unget bits

+ after determining how many we need, and those extra bits could

+ be set to anything. (They're noise from future symbols.) At

+ each level we're really only interested in the first few bits,

+ so here we set all the trailing to-be-ignored bits to 1 so they

+ don't affect the value>limit[length] comparison. */

+ limit[i] = ( pp << ( maxLen - i ) ) - 1;

+ base[i+1] = pp - ( t += temp[i] );

+ limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */

+ limit[maxLen] = pp + temp[maxLen] - 1;

+ /* We've finished reading and digesting the block header. Now read this

+ block's huffman coded symbols from the file and undo the huffman coding

+ and run length encoding, saving the result into dbuf[dbufCount++]=uc */

- /* Initialize symbol occurrence counters and symbol Move To Front table */

- mtfSymbol[i]=(unsigned char)i;

- /* Loop through compressed symbols. */

- runPos=dbufCount=symCount=selector=0;

- /* Determine which huffman coding group to use. */

- if(selector>=nSelectors) return RETVAL_DATA_ERROR;

- hufGroup=bd->groups+selectors[selector++];

- limit=hufGroup->limit-1;

- /* Read next huffman-coded symbol. */

- /* Note: It is far cheaper to read maxLen bits and back up than it is

- to read minLen bits and then an additional bit at a time, testing

- as we go. Because there is a trailing last block (with file CRC),

- there is no danger of the overread causing an unexpected EOF for a

- valid compressed file. As a further optimization, we do the read

- inline (falling back to a call to get_bits if the buffer runs

- dry). The following (up to got_huff_bits:) is equivalent to

- j=get_bits(bd,hufGroup->maxLen);

- while (bd->inbufBitCount<hufGroup->maxLen) {

- if(bd->inbufPos==bd->inbufCount) {

- j = get_bits(bd,hufGroup->maxLen);

- bd->inbufBits=(bd->inbufBits<<8)|bd->inbuf[bd->inbufPos++];

- bd->inbufBitCount-=hufGroup->maxLen;

- j = (bd->inbufBits>>bd->inbufBitCount)&((1<<hufGroup->maxLen)-1);

+ /* Initialize symbol occurrence counters and symbol Move To Front table */

+ for ( i = 0;i < 256;i++ )

+ mtfSymbol[i] = ( unsigned char )i;

+ /* Loop through compressed symbols. */

+ runPos = dbufCount = symCount = selector = 0;

+ /* Determine which huffman coding group to use. */

+ symCount = GROUP_SIZE - 1;

+ if ( selector >= nSelectors ) return RETVAL_DATA_ERROR;

+ hufGroup = bd->groups + selectors[selector++];

+ base = hufGroup->base - 1;

+ limit = hufGroup->limit - 1;

+ /* Read next huffman-coded symbol. */

+ /* Note: It is far cheaper to read maxLen bits and back up than it is

+ to read minLen bits and then an additional bit at a time, testing

+ as we go. Because there is a trailing last block (with file CRC),

+ there is no danger of the overread causing an unexpected EOF for a

+ valid compressed file. As a further optimization, we do the read

+ inline (falling back to a call to get_bits if the buffer runs

+ dry). The following (up to got_huff_bits:) is equivalent to

+ j=get_bits(bd,hufGroup->maxLen);

+ while ( bd->inbufBitCount < hufGroup->maxLen )

+ if ( bd->inbufPos == bd->inbufCount )

+ j = get_bits( bd, hufGroup->maxLen );

+ bd->inbufBits = ( bd->inbufBits << 8 ) | bd->inbuf[bd->inbufPos++];

+ bd->inbufBitCount += 8;

+ bd->inbufBitCount -= hufGroup->maxLen;

+ j = ( bd->inbufBits >> bd->inbufBitCount ) & ( ( 1 << hufGroup->maxLen ) - 1 );

- /* Figure how how many bits are in next symbol and unget extras */

- bd->inbufBitCount += (hufGroup->maxLen - i);

- /* Huffman decode value to get nextSym (with bounds checking) */

- if ((i > hufGroup->maxLen)

- || (((unsigned)(j=(j>>(hufGroup->maxLen-i))-base[i]))

- return RETVAL_DATA_ERROR;

- nextSym = hufGroup->permute[j];

- /* We have now decoded the symbol, which indicates either a new literal

- byte, or a repeated run of the most recent literal byte. First,

- check if nextSym indicates a repeated run, and if so loop collecting

- how many times to repeat the last literal. */

- if (((unsigned)nextSym) <= SYMBOL_RUNB) { /* RUNA or RUNB */

- /* If this is the start of a new run, zero out counter */

- /* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at

- each bit position, add 1 or 2 instead. For example,

- 1011 is 1<<0 + 1<<1 + 2<<2. 1010 is 2<<0 + 2<<1 + 1<<2.

- You can make any bit pattern that way using 1 less symbol than

- the basic or 0/1 method (except all bits 0, which would use no

- symbols, but a run of length 0 doesn't mean anything in this

- context). Thus space is saved. */

- t += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */

- /* When we hit the first non-run symbol after a run, we now know

- how many times to repeat the last literal, so append that many

- copies to our buffer of decoded symbols (dbuf) now. (The last

- literal used is the one at the head of the mtfSymbol array.) */

- if(dbufCount+t>=dbufSize) return RETVAL_DATA_ERROR;

+ /* Figure how how many bits are in next symbol and unget extras */

+ while ( j > limit[i] ) ++i;

+ bd->inbufBitCount += ( hufGroup->maxLen - i );

+ /* Huffman decode value to get nextSym (with bounds checking) */

+ if ( ( i > hufGroup->maxLen )

+ || ( ( ( unsigned )( j = ( j >> ( hufGroup->maxLen - i ) ) - base[i] ) )

+ return RETVAL_DATA_ERROR;

+ nextSym = hufGroup->permute[j];

+ /* We have now decoded the symbol, which indicates either a new literal

+ byte, or a repeated run of the most recent literal byte. First,

+ check if nextSym indicates a repeated run, and if so loop collecting

+ how many times to repeat the last literal. */

+ if ( ( ( unsigned )nextSym ) <= SYMBOL_RUNB )

+ /* If this is the start of a new run, zero out counter */

+ /* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at

+ each bit position, add 1 or 2 instead. For example,

+ 1011 is 1<<0 + 1<<1 + 2<<2. 1010 is 2<<0 + 2<<1 + 1<<2.

+ You can make any bit pattern that way using 1 less symbol than

+ the basic or 0/1 method (except all bits 0, which would use no

+ symbols, but a run of length 0 doesn't mean anything in this

+ context). Thus space is saved. */

+ t += ( runPos << nextSym ); /* +runPos if RUNA; +2*runPos if RUNB */

+ /* When we hit the first non-run symbol after a run, we now know

+ how many times to repeat the last literal, so append that many

+ copies to our buffer of decoded symbols (dbuf) now. (The last

+ literal used is the one at the head of the mtfSymbol array.) */

+ if ( dbufCount + t >= dbufSize ) return RETVAL_DATA_ERROR;

- uc = symToByte[mtfSymbol[0]];

- while(t--) dbuf[dbufCount++]=uc;

- /* Is this the terminating symbol? */

- if(nextSym>symTotal) break;

- /* At this point, nextSym indicates a new literal character. Subtract

- one to get the position in the MTF array at which this literal is

- currently to be found. (Note that the result can't be -1 or 0,

- because 0 and 1 are RUNA and RUNB. But another instance of the

- first symbol in the mtf array, position 0, would have been handled

- as part of a run above. Therefore 1 unused mtf position minus

- 2 non-literal nextSym values equals -1.) */

- if(dbufCount>=dbufSize) return RETVAL_DATA_ERROR;

- /* Adjust the MTF array. Since we typically expect to move only a

- * small number of symbols, and are bound by 256 in any case, using

- * memmove here would typically be bigger and slower due to function

- * call overhead and other assorted setup costs. */

- mtfSymbol[i] = mtfSymbol[i-1];

- /* We have our literal byte. Save it into dbuf. */

- dbuf[dbufCount++] = (unsigned int)uc;

- /* At this point, we've read all the huffman-coded symbols (and repeated

- runs) for this block from the input stream, and decoded them into the

- intermediate buffer. There are dbufCount many decoded bytes in dbuf[].

- Now undo the Burrows-Wheeler transform on dbuf.

- See http://dogma.net/markn/articles/bwt/bwt.htm

- /* Turn byteCount into cumulative occurrence counts of 0 to n-1. */

- /* Figure out what order dbuf would be in if we sorted it. */

- for (i=0;i<dbufCount;i++) {

- uc=(unsigned char)(dbuf[i] & 0xff);

- dbuf[byteCount[uc]] |= (i << 8);

- /* Decode first byte by hand to initialize "previous" byte. Note that it

- doesn't get output, and if the first three characters are identical

- it doesn't qualify as a run (hence writeRunCountdown=5). */

- if(origPtr>=dbufCount) return RETVAL_DATA_ERROR;

- bd->writePos=dbuf[origPtr];

- bd->writeCurrent=(unsigned char)(bd->writePos&0xff);

- bd->writeRunCountdown=5;

- bd->writeCount=dbufCount;

+ uc = symToByte[mtfSymbol[0]];

+ while ( t-- ) dbuf[dbufCount++] = uc;

+ /* Is this the terminating symbol? */

+ if ( nextSym > symTotal ) break;

+ /* At this point, nextSym indicates a new literal character. Subtract

+ one to get the position in the MTF array at which this literal is

+ currently to be found. (Note that the result can't be -1 or 0,

+ because 0 and 1 are RUNA and RUNB. But another instance of the

+ first symbol in the mtf array, position 0, would have been handled

+ as part of a run above. Therefore 1 unused mtf position minus

+ 2 non-literal nextSym values equals -1.) */

+ if ( dbufCount >= dbufSize ) return RETVAL_DATA_ERROR;

+ /* Adjust the MTF array. Since we typically expect to move only a

+ * small number of symbols, and are bound by 256 in any case, using

+ * memmove here would typically be bigger and slower due to function

+ * call overhead and other assorted setup costs. */

+ mtfSymbol[i] = mtfSymbol[i-1];

+ /* We have our literal byte. Save it into dbuf. */

+ dbuf[dbufCount++] = ( unsigned int )uc;

+ /* At this point, we've read all the huffman-coded symbols (and repeated

+ runs) for this block from the input stream, and decoded them into the

+ intermediate buffer. There are dbufCount many decoded bytes in dbuf[].

+ Now undo the Burrows-Wheeler transform on dbuf.

+ See http://dogma.net/markn/articles/bwt/bwt.htm

+ /* Turn byteCount into cumulative occurrence counts of 0 to n-1. */

+ for ( i = 0;i < 256;i++ )

+ /* Figure out what order dbuf would be in if we sorted it. */

+ for ( i = 0;i < dbufCount;i++ )

+ uc = ( unsigned char )( dbuf[i] & 0xff );

+ dbuf[byteCount[uc]] |= ( i << 8 );

+ /* Decode first byte by hand to initialize "previous" byte. Note that it

+ doesn't get output, and if the first three characters are identical

+ it doesn't qualify as a run (hence writeRunCountdown=5). */

+ if ( origPtr >= dbufCount ) return RETVAL_DATA_ERROR;

+ bd->writePos = dbuf[origPtr];

+ bd->writeCurrent = ( unsigned char )( bd->writePos & 0xff );

+ bd->writeRunCountdown = 5;

+ bd->writeCount = dbufCount;

/* Undo burrows-wheeler transform on intermediate buffer to produce output.

are ignored, data is written to out_fd and return is RETVAL_OK or error.

-extern int read_bunzip(bunzip_data *bd, char *outbuf, int len)

+extern int read_bunzip( bunzip_data *bd, char *outbuf, int len )

- const unsigned int *dbuf;

- int pos,current,previous,gotcount;

+ const unsigned int *dbuf;

+ int pos, current, previous, gotcount;

- /* If last read was short due to end of file, return last block now */

- /* if(bd->writeCount<0) return bd->writeCount; */

- /* james@bx.psu.edu: writeCount goes to -1 when the buffer is fully

- decoded, which results in this returning RETVAL_LAST_BLOCK, also

- equal to -1... Confusing, I'm returning 0 here to indicate no

- bytes written into the buffer */

- if(bd->writeCount<0) return 0;

+ /* If last read was short due to end of file, return last block now */

+ /* if(bd->writeCount<0) return bd->writeCount; */

- current=bd->writeCurrent;

+ /* james@jamestaylor.org: writeCount goes to -1 when the buffer is fully

+ decoded, which results in this returning RETVAL_LAST_BLOCK, also

+ equal to -1... Confusing, I'm returning 0 here to indicate no

+ bytes written into the buffer */

+ if ( bd->writeCount < 0 ) return 0;

- /* We will always have pending decoded data to write into the output

- buffer unless this is the very first call (in which case we haven't

- huffman-decoded a block into the intermediate buffer yet). */

+ current = bd->writeCurrent;

- /* Inside the loop, writeCopies means extra copies (beyond 1) */

- /* Loop outputting bytes */

- /* Write next byte into output buffer, updating CRC */

- /* If the output buffer is full, snapshot state and return */

- bd->writeCurrent=current;

- outbuf[gotcount++] = current;

- bd->writeCRC=(((bd->writeCRC)<<8)

- ^bd->crc32Table[((bd->writeCRC)>>24)^current]);

- /* Loop now if we're outputting multiple copies of this byte */

+ /* We will always have pending decoded data to write into the output

+ buffer unless this is the very first call (in which case we haven't

+ huffman-decoded a block into the intermediate buffer yet). */

+ /* Inside the loop, writeCopies means extra copies (beyond 1) */

+ /* Loop outputting bytes */

+ /* Write next byte into output buffer, updating CRC */

+ /* If the output buffer is full, snapshot state and return */

+ bd->writeCurrent = current;

+ outbuf[gotcount++] = current;

+ bd->writeCRC = ( ( ( bd->writeCRC ) << 8 )

+ ^ bd->crc32Table[( ( bd->writeCRC )>>24 )^current] );

+ /* Loop now if we're outputting multiple copies of this byte */

- if (!bd->writeCount--) break;

- /* Follow sequence vector to undo Burrows-Wheeler transform */

- /* After 3 consecutive copies of the same byte, the 4th is a repeat

- count. We count down from 4 instead

- * of counting up because testing for non-zero is faster */

- if(--bd->writeRunCountdown) {

- if(current!=previous) bd->writeRunCountdown=4;

- /* We have a repeated run, this byte indicates the count */

- bd->writeCopies=current;

- bd->writeRunCountdown=5;

- /* Sometimes there are just 3 bytes (run length 0) */

- if(!bd->writeCopies) goto decode_next_byte;

- /* Subtract the 1 copy we'd output anyway to get extras */

- /* Decompression of this block completed successfully */

- bd->writeCRC=~bd->writeCRC;

- bd->totalCRC=((bd->totalCRC<<1) | (bd->totalCRC>>31)) ^ bd->writeCRC;

- /* If this block had a CRC error, force file level CRC error. */

- if(bd->writeCRC!=bd->headerCRC) {

- bd->totalCRC=bd->headerCRC+1;

- return RETVAL_LAST_BLOCK;

- /* james@bx.psu.edu -- rather than falling through we return here */

+ if ( !bd->writeCount-- ) break;

+ /* Follow sequence vector to undo Burrows-Wheeler transform */

+ /* After 3 consecutive copies of the same byte, the 4th is a repeat

+ count. We count down from 4 instead

+ * of counting up because testing for non-zero is faster */

+ if ( --bd->writeRunCountdown )

+ if ( current != previous ) bd->writeRunCountdown = 4;

+ /* We have a repeated run, this byte indicates the count */

+ bd->writeCopies = current;

+ bd->writeRunCountdown = 5;

+ /* Sometimes there are just 3 bytes (run length 0) */

+ if ( !bd->writeCopies ) goto decode_next_byte;

+ /* Subtract the 1 copy we'd output anyway to get extras */

+ /* Decompression of this block completed successfully */

+ bd->writeCRC = ~bd->writeCRC;

+ bd->totalCRC = ( ( bd->totalCRC << 1 ) | ( bd->totalCRC >> 31 ) ) ^ bd->writeCRC;

+ /* If this block had a CRC error, force file level CRC error. */

+ if ( bd->writeCRC != bd->headerCRC )

+ bd->totalCRC = bd->headerCRC + 1;

+ return RETVAL_LAST_BLOCK;

+ /* james@jamestaylor.org -- rather than falling through we return here */

/* Refill the intermediate buffer by huffman-decoding next block of input */

- /* (previous is just a convenient unused temp variable here) */

- status=get_next_block(bd);

+ /* (previous is just a convenient unused temp variable here) */

+ status = get_next_block( bd );

+ bd->writeCount = status;

- bd->writeCRC=0xffffffffUL;

+ bd->writeCRC = 0xffffffffUL;

/* Allocate the structure, read file header. If in_fd==-1, inbuf must contain

a complete bunzip file (len bytes long). If in_fd!=-1, inbuf and len are

ignored, and data is read from file handle into temporary buffer. */

-extern int start_bunzip(bunzip_data **bdp, int in_fd, char *inbuf, int len)

+extern int start_bunzip( bunzip_data **bdp, int in_fd, char *inbuf, int len )

- const unsigned int BZh0=(((unsigned int)'B')<<24)+(((unsigned int)'Z')<<16)

- +(((unsigned int)'h')<<8)+(unsigned int)'0';

+ const unsigned int BZh0 = ( ( ( unsigned int )'B' ) << 24 ) + ( ( ( unsigned int )'Z' ) << 16 )

+ + ( ( ( unsigned int )'h' ) << 8 ) + ( unsigned int )'0';

- /* Figure out how much data to allocate */

- if(in_fd!=-1) i+=IOBUF_SIZE;

- /* Allocate bunzip_data. Most fields initialize to zero. */

- if(!(bd=*bdp=malloc(i))) return RETVAL_OUT_OF_MEMORY;

- memset(bd,0,sizeof(bunzip_data));

- /* Setup input buffer */

- if(-1==(bd->in_fd=in_fd)) {

- } else bd->inbuf=(unsigned char *)(bd+1);

- /* Init the CRC32 table (big endian) */

- c=c&0x80000000 ? (c<<1)^0x04c11db7 : (c<<1);

- /* Setup for I/O error handling via longjmp */

+ /* Figure out how much data to allocate */

+ i = sizeof( bunzip_data );

+ if ( in_fd != -1 ) i += IOBUF_SIZE;

+ /* Allocate bunzip_data. Most fields initialize to zero. */

+ if ( !( bd = *bdp = malloc( i ) ) ) return RETVAL_OUT_OF_MEMORY;

+ memset( bd, 0, sizeof( bunzip_data ) );

+ /* Setup input buffer */

+ if ( -1 == ( bd->in_fd = in_fd ) )

+ else bd->inbuf = ( unsigned char * )( bd + 1 );

+ /* Init the CRC32 table (big endian) */

+ for ( i = 0;i < 256;i++ )

+ c = c & 0x80000000 ? ( c << 1 ) ^ 0x04c11db7 : ( c << 1 );

+ /* Setup for I/O error handling via longjmp */

+ i = setjmp( bd->jmpbuf );

- /* Ensure that file starts with "BZh['1'-'9']." */

- if (((unsigned int)(i-BZh0-1)) >= 9) return RETVAL_NOT_BZIP_DATA;

+ /* Ensure that file starts with "BZh['1'-'9']." */

+ i = get_bits( bd, 32 );

+ if ( ( ( unsigned int )( i - BZh0 - 1 ) ) >= 9 ) return RETVAL_NOT_BZIP_DATA;

- /* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of

- uncompressed data. Allocate intermediate buffer for block. */

- bd->dbufSize=100000*(i-BZh0);

+ /* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of

+ uncompressed data. Allocate intermediate buffer for block. */

+ bd->dbufSize = 100000 * ( i - BZh0 );

- if(!(bd->dbuf=malloc(bd->dbufSize * sizeof(int))))

- return RETVAL_OUT_OF_MEMORY;

+ if ( !( bd->dbuf = malloc( bd->dbufSize * sizeof( int ) ) ) )

+ return RETVAL_OUT_OF_MEMORY;

/* Example usage: decompress src_fd to dst_fd. (Stops at end of bzip data,

-extern int uncompressStream(int src_fd, int dst_fd)

+extern int uncompressStream( int src_fd, int dst_fd )

- if(!(outbuf=malloc(IOBUF_SIZE))) return RETVAL_OUT_OF_MEMORY;

- if(!(i=start_bunzip(&bd,src_fd,0,0))) {

- if (((i=init_block(bd)) < 0)) break;

+ if ( !( outbuf = malloc( IOBUF_SIZE ) ) ) return RETVAL_OUT_OF_MEMORY;

+ if ( !( i = start_bunzip( &bd, src_fd, 0, 0 ) ) )

+ if ( ( ( i = init_block( bd ) ) < 0 ) ) break;

// fprintf( stderr, "init: %d\n", i );

-~~ if((i=~~read_bunzip(bd,outbuf,IOBUF_SIZE~~)~~) <= 0) break;

+ if ( ( i = read_bunzip( bd, outbuf, IOBUF_SIZE ) ) <= 0 ) break;

// fprintf( stderr, "read: %d\n", i );

- if(i!=write(dst_fd,outbuf,i)) {

- i=RETVAL_UNEXPECTED_OUTPUT_EOF;

- /* Check CRC and release memory */

- if(i==RETVAL_LAST_BLOCK && bd->headerCRC==bd->totalCRC) i=RETVAL_OK;

- if(bd->dbuf) free(bd->dbuf);

+ if ( i != write( dst_fd, outbuf, i ) )

+ i = RETVAL_UNEXPECTED_OUTPUT_EOF;

+ /* Check CRC and release memory */

+ if ( i == RETVAL_LAST_BLOCK && bd->headerCRC == bd->totalCRC ) i = RETVAL_OK;

+ if ( bd->dbuf ) free( bd->dbuf );

-static char * const bunzip_errors[]={NULL,"Bad file checksum","Not bzip data",

- "Unexpected input EOF","Unexpected output EOF","Data error",

- "Out of memory","Obsolete (pre 0.9.5) bzip format not supported."};

+static char * const bunzip_errors[] =

+ NULL, "Bad file checksum", "Not bzip data",

+ "Unexpected input EOF", "Unexpected output EOF", "Data error",

+ "Out of memory", "Obsolete (pre 0.9.5) bzip format not supported."

/* Dumb little test thing, decompress stdin to stdout */

-int main(int argc, char *argv[])

+int main( int argc, char *argv[] )

- int i=uncompressStream(0,1);

+ int i = uncompressStream( 0, 1 );

- if(i) fprintf(stderr,"%d: %s\n", i, bunzip_errors[-i]);

- else if(read(0,&c,1)) fprintf(stderr,"Trailing garbage ignored\n");

+ if ( i ) fprintf( stderr, "%d: %s\n", i, bunzip_errors[-i] );

+ else if ( read( 0, &c, 1 ) ) fprintf( stderr, "Trailing garbage ignored\n" );