bunzip2: big style cleanup. No code changes apart from one s/write/safe_write/
(verified with objdump).
This commit is contained in:
Denis Vlasenko
parent
a9d7d24e1f
commit
b38cf3ff8a
@ -55,7 +55,7 @@
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/* This is what we know about each Huffman coding group */
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struct group_data {
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/* We have an extra slot at the end of limit[] for a sentinal value. */
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int limit[MAX_HUFCODE_BITS+1],base[MAX_HUFCODE_BITS],permute[MAX_SYMBOLS];
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int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS];
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int minLen, maxLen;
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};
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@ -65,13 +65,13 @@ struct group_data {
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typedef struct {
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/* State for interrupting output loop */
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int writeCopies,writePos,writeRunCountdown,writeCount,writeCurrent;
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int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent;
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/* I/O tracking data (file handles, buffers, positions, etc.) */
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int in_fd,out_fd,inbufCount,inbufPos /*,outbufPos*/;
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int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/;
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unsigned char *inbuf /*,*outbuf*/;
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unsigned int inbufBitCount, inbufBits;
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unsigned inbufBitCount, inbufBits;
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/* The CRC values stored in the block header and calculated from the data */
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@ -79,7 +79,7 @@ typedef struct {
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uint32_t *crc32Table;
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/* Intermediate buffer and its size (in bytes) */
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unsigned int *dbuf, dbufSize;
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unsigned *dbuf, dbufSize;
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/* These things are a bit too big to go on the stack */
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@ -94,42 +94,43 @@ typedef struct {
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/* Return the next nnn bits of input. All reads from the compressed input
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are done through this function. All reads are big endian */
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static unsigned int get_bits(bunzip_data *bd, char bits_wanted)
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static unsigned get_bits(bunzip_data *bd, char bits_wanted)
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{
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unsigned int bits=0;
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unsigned bits = 0;
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/* If we need to get more data from the byte buffer, do so. (Loop getting
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one byte at a time to enforce endianness and avoid unaligned access.) */
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while (bd->inbufBitCount<bits_wanted) {
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while (bd->inbufBitCount < bits_wanted) {
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/* If we need to read more data from file into byte buffer, do so */
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if(bd->inbufPos==bd->inbufCount) {
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if((bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE)) <= 0)
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longjmp(bd->jmpbuf,RETVAL_UNEXPECTED_INPUT_EOF);
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bd->inbufPos=0;
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if (bd->inbufPos == bd->inbufCount) {
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bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE);
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if (bd->inbufCount <= 0)
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longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF);
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bd->inbufPos = 0;
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}
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/* Avoid 32-bit overflow (dump bit buffer to top of output) */
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if(bd->inbufBitCount>=24) {
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bits=bd->inbufBits&((1<<bd->inbufBitCount)-1);
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bits_wanted-=bd->inbufBitCount;
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bits<<=bits_wanted;
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bd->inbufBitCount=0;
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if (bd->inbufBitCount >= 24) {
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bits = bd->inbufBits & ((1 << bd->inbufBitCount) - 1);
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bits_wanted -= bd->inbufBitCount;
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bits <<= bits_wanted;
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bd->inbufBitCount = 0;
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}
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/* Grab next 8 bits of input from buffer. */
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bd->inbufBits=(bd->inbufBits<<8)|bd->inbuf[bd->inbufPos++];
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bd->inbufBitCount+=8;
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bd->inbufBits = (bd->inbufBits<<8) | bd->inbuf[bd->inbufPos++];
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bd->inbufBitCount += 8;
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}
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/* Calculate result */
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bd->inbufBitCount-=bits_wanted;
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bits|=(bd->inbufBits>>bd->inbufBitCount)&((1<<bits_wanted)-1);
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bd->inbufBitCount -= bits_wanted;
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bits |= (bd->inbufBits >> bd->inbufBitCount) & ((1 << bits_wanted) - 1);
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return bits;
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}
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@ -139,26 +140,26 @@ static unsigned int get_bits(bunzip_data *bd, char bits_wanted)
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static int get_next_block(bunzip_data *bd)
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{
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struct group_data *hufGroup;
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int dbufCount,nextSym,dbufSize,groupCount,*base,*limit,selector,
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i,j,k,t,runPos,symCount,symTotal,nSelectors,byteCount[256];
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int dbufCount, nextSym, dbufSize, groupCount, *base, *limit, selector,
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i, j, k, t, runPos, symCount, symTotal, nSelectors, byteCount[256];
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unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;
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unsigned int *dbuf,origPtr;
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unsigned *dbuf, origPtr;
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dbuf=bd->dbuf;
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dbufSize=bd->dbufSize;
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selectors=bd->selectors;
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dbuf = bd->dbuf;
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dbufSize = bd->dbufSize;
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selectors = bd->selectors;
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/* Reset longjmp I/O error handling */
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i=setjmp(bd->jmpbuf);
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i = setjmp(bd->jmpbuf);
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if (i) return i;
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/* Read in header signature and CRC, then validate signature.
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(last block signature means CRC is for whole file, return now) */
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i = get_bits(bd,24);
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j = get_bits(bd,24);
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bd->headerCRC=get_bits(bd,32);
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i = get_bits(bd, 24);
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j = get_bits(bd, 24);
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bd->headerCRC = get_bits(bd, 32);
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if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK;
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if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA;
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@ -166,8 +167,9 @@ static int get_next_block(bunzip_data *bd)
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some code for this in busybox 1.0.0-pre3, but nobody ever noticed that
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it didn't actually work. */
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if (get_bits(bd,1)) return RETVAL_OBSOLETE_INPUT;
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if ((origPtr=get_bits(bd,24)) > dbufSize) return RETVAL_DATA_ERROR;
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if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT;
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origPtr = get_bits(bd, 24);
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if (origPtr > dbufSize) return RETVAL_DATA_ERROR;
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/* mapping table: if some byte values are never used (encoding things
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like ascii text), the compression code removes the gaps to have fewer
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@ -175,48 +177,52 @@ static int get_next_block(bunzip_data *bd)
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values were present. We make a translation table to convert the symbols
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back to the corresponding bytes. */
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t=get_bits(bd, 16);
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symTotal=0;
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for (i=0;i<16;i++) {
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if(t&(1<<(15-i))) {
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k=get_bits(bd,16);
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for (j=0;j<16;j++)
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if(k&(1<<(15-j))) symToByte[symTotal++]=(16*i)+j;
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t = get_bits(bd, 16);
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symTotal = 0;
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for (i = 0; i < 16; i++) {
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if (t & (1 << (15-i))) {
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k = get_bits(bd, 16);
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for (j = 0; j < 16; j++)
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if (k & (1 << (15-j)))
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symToByte[symTotal++] = (16*i) + j;
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}
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}
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/* How many different Huffman coding groups does this block use? */
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groupCount=get_bits(bd,3);
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if (groupCount<2 || groupCount>MAX_GROUPS) return RETVAL_DATA_ERROR;
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groupCount = get_bits(bd, 3);
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if (groupCount < 2 || groupCount > MAX_GROUPS)
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return RETVAL_DATA_ERROR;
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/* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding
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group. Read in the group selector list, which is stored as MTF encoded
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bit runs. (MTF=Move To Front, as each value is used it's moved to the
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start of the list.) */
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if(!(nSelectors=get_bits(bd, 15))) return RETVAL_DATA_ERROR;
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for (i=0; i<groupCount; i++) mtfSymbol[i] = i;
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for (i=0; i<nSelectors; i++) {
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nSelectors = get_bits(bd, 15);
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if (!nSelectors) return RETVAL_DATA_ERROR;
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for (i = 0; i < groupCount; i++) mtfSymbol[i] = i;
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for (i = 0; i < nSelectors; i++) {
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/* Get next value */
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for (j=0;get_bits(bd,1);j++) if (j>=groupCount) return RETVAL_DATA_ERROR;
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for (j = 0; get_bits(bd, 1); j++)
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if (j>=groupCount) return RETVAL_DATA_ERROR;
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/* Decode MTF to get the next selector */
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uc = mtfSymbol[j];
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for (;j;j--) mtfSymbol[j] = mtfSymbol[j-1];
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mtfSymbol[0]=selectors[i]=uc;
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mtfSymbol[0] = selectors[i] = uc;
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}
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/* Read the Huffman coding tables for each group, which code for symTotal
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literal symbols, plus two run symbols (RUNA, RUNB) */
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symCount=symTotal+2;
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for (j=0; j<groupCount; j++) {
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unsigned char length[MAX_SYMBOLS],temp[MAX_HUFCODE_BITS+1];
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int minLen, maxLen, pp;
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symCount = symTotal + 2;
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for (j = 0; j < groupCount; j++) {
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unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1];
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int minLen, maxLen, pp;
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/* Read Huffman code lengths for each symbol. They're stored in
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a way similar to mtf; record a starting value for the first symbol,
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@ -225,17 +231,17 @@ static int get_next_block(bunzip_data *bd)
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an optimization that makes the test inside the loop simpler: symbol
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length 0 becomes negative, so an unsigned inequality catches it.) */
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t=get_bits(bd, 5)-1;
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t = get_bits(bd, 5) - 1;
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for (i = 0; i < symCount; i++) {
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for (;;) {
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if (((unsigned)t) > (MAX_HUFCODE_BITS-1))
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if ((unsigned)t > (MAX_HUFCODE_BITS-1))
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return RETVAL_DATA_ERROR;
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/* If first bit is 0, stop. Else second bit indicates whether
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to increment or decrement the value. Optimization: grab 2
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bits and unget the second if the first was 0. */
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k = get_bits(bd,2);
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k = get_bits(bd, 2);
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if (k < 2) {
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bd->inbufBitCount++;
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break;
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@ -243,20 +249,20 @@ static int get_next_block(bunzip_data *bd)
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/* Add one if second bit 1, else subtract 1. Avoids if/else */
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t+=(((k+1)&2)-1);
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t += (((k+1) & 2) - 1);
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}
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/* Correct for the initial -1, to get the final symbol length */
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length[i]=t+1;
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length[i] = t + 1;
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}
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/* Find largest and smallest lengths in this group */
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minLen=maxLen=length[0];
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minLen = maxLen = length[0];
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for (i = 1; i < symCount; i++) {
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if(length[i] > maxLen) maxLen = length[i];
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else if(length[i] < minLen) minLen = length[i];
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if (length[i] > maxLen) maxLen = length[i];
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else if (length[i] < minLen) minLen = length[i];
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}
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/* Calculate permute[], base[], and limit[] tables from length[].
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@ -270,7 +276,7 @@ static int get_next_block(bunzip_data *bd)
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* length: each code with a value>limit[length] needs another bit.
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*/
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hufGroup=bd->groups+j;
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hufGroup = bd->groups + j;
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hufGroup->minLen = minLen;
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hufGroup->maxLen = maxLen;
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@ -278,30 +284,31 @@ static int get_next_block(bunzip_data *bd)
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and limit array pointers so we're not always wasting the first
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entry. We do this again when using them (during symbol decoding).*/
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base=hufGroup->base-1;
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limit=hufGroup->limit-1;
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base = hufGroup->base - 1;
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limit = hufGroup->limit - 1;
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/* Calculate permute[]. Concurently, initialize temp[] and limit[]. */
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pp=0;
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for (i=minLen;i<=maxLen;i++) {
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temp[i]=limit[i]=0;
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for (t=0;t<symCount;t++)
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if(length[t]==i) hufGroup->permute[pp++] = t;
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pp = 0;
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for (i = minLen; i <= maxLen; i++) {
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temp[i] = limit[i] = 0;
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for (t = 0; t < symCount; t++)
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if (length[t] == i)
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hufGroup->permute[pp++] = t;
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}
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/* Count symbols coded for at each bit length */
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for (i=0;i<symCount;i++) temp[length[i]]++;
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for (i = 0; i < symCount; i++) temp[length[i]]++;
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/* Calculate limit[] (the largest symbol-coding value at each bit
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* length, which is (previous limit<<1)+symbols at this level), and
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* base[] (number of symbols to ignore at each bit length, which is
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* limit minus the cumulative count of symbols coded for already). */
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pp=t=0;
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for (i=minLen; i<maxLen; i++) {
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pp+=temp[i];
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pp = t = 0;
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for (i = minLen; i < maxLen; i++) {
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pp += temp[i];
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/* We read the largest possible symbol size and then unget bits
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after determining how many we need, and those extra bits could
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@ -310,13 +317,14 @@ static int get_next_block(bunzip_data *bd)
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so here we set all the trailing to-be-ignored bits to 1 so they
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don't affect the value>limit[length] comparison. */
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limit[i]= (pp << (maxLen - i)) - 1;
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pp<<=1;
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base[i+1]=pp-(t+=temp[i]);
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limit[i] = (pp << (maxLen - i)) - 1;
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pp <<= 1;
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t += temp[i];
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base[i+1] = pp - t;
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}
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limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */
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limit[maxLen]=pp+temp[maxLen]-1;
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base[minLen]=0;
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limit[maxLen] = pp + temp[maxLen] - 1;
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base[minLen] = 0;
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}
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/* We've finished reading and digesting the block header. Now read this
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@ -325,24 +333,24 @@ static int get_next_block(bunzip_data *bd)
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/* Initialize symbol occurrence counters and symbol Move To Front table */
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for (i=0;i<256;i++) {
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for (i = 0; i < 256; i++) {
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byteCount[i] = 0;
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mtfSymbol[i]=(unsigned char)i;
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mtfSymbol[i] = (unsigned char)i;
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}
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/* Loop through compressed symbols. */
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runPos=dbufCount=selector=0;
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runPos = dbufCount = selector = 0;
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for (;;) {
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/* fetch next Huffman coding group from list. */
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symCount=GROUP_SIZE-1;
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if(selector>=nSelectors) return RETVAL_DATA_ERROR;
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hufGroup=bd->groups+selectors[selector++];
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base=hufGroup->base-1;
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limit=hufGroup->limit-1;
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continue_this_group:
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symCount = GROUP_SIZE - 1;
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if (selector >= nSelectors) return RETVAL_DATA_ERROR;
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hufGroup = bd->groups + selectors[selector++];
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base = hufGroup->base - 1;
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limit = hufGroup->limit - 1;
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continue_this_group:
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/* Read next Huffman-coded symbol. */
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@ -353,33 +361,34 @@ continue_this_group:
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valid compressed file. As a further optimization, we do the read
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inline (falling back to a call to get_bits if the buffer runs
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dry). The following (up to got_huff_bits:) is equivalent to
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j=get_bits(bd,hufGroup->maxLen);
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j = get_bits(bd, hufGroup->maxLen);
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*/
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while (bd->inbufBitCount<hufGroup->maxLen) {
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if(bd->inbufPos==bd->inbufCount) {
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j = get_bits(bd,hufGroup->maxLen);
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while (bd->inbufBitCount < hufGroup->maxLen) {
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if (bd->inbufPos == bd->inbufCount) {
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j = get_bits(bd, hufGroup->maxLen);
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goto got_huff_bits;
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}
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bd->inbufBits=(bd->inbufBits<<8)|bd->inbuf[bd->inbufPos++];
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bd->inbufBitCount+=8;
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bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++];
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bd->inbufBitCount += 8;
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};
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bd->inbufBitCount-=hufGroup->maxLen;
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j = (bd->inbufBits>>bd->inbufBitCount)&((1<<hufGroup->maxLen)-1);
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bd->inbufBitCount -= hufGroup->maxLen;
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j = (bd->inbufBits >> bd->inbufBitCount) & ((1 << hufGroup->maxLen) - 1);
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got_huff_bits:
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got_huff_bits:
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/* Figure how how many bits are in next symbol and unget extras */
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i=hufGroup->minLen;
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while (j>limit[i]) ++i;
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i = hufGroup->minLen;
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while (j > limit[i]) ++i;
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bd->inbufBitCount += (hufGroup->maxLen - i);
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/* Huffman decode value to get nextSym (with bounds checking) */
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if ((i > hufGroup->maxLen)
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|| (((unsigned)(j=(j>>(hufGroup->maxLen-i))-base[i]))
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>= MAX_SYMBOLS))
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if (i > hufGroup->maxLen)
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return RETVAL_DATA_ERROR;
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j = (j >> (hufGroup->maxLen - i)) - base[i];
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if ((unsigned)j >= MAX_SYMBOLS)
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return RETVAL_DATA_ERROR;
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nextSym = hufGroup->permute[j];
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@ -388,11 +397,11 @@ got_huff_bits:
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check if nextSym indicates a repeated run, and if so loop collecting
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how many times to repeat the last literal. */
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||||
|
||||
if (((unsigned)nextSym) <= SYMBOL_RUNB) { /* RUNA or RUNB */
|
||||
if ((unsigned)nextSym <= SYMBOL_RUNB) { /* RUNA or RUNB */
|
||||
|
||||
/* If this is the start of a new run, zero out counter */
|
||||
|
||||
if(!runPos) {
|
||||
if (!runPos) {
|
||||
runPos = 1;
|
||||
t = 0;
|
||||
}
|
||||
@ -406,7 +415,7 @@ got_huff_bits:
|
||||
context). Thus space is saved. */
|
||||
|
||||
t += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */
|
||||
if(runPos < dbufSize) runPos <<= 1;
|
||||
if (runPos < dbufSize) runPos <<= 1;
|
||||
goto end_of_huffman_loop;
|
||||
}
|
||||
|
||||
@ -415,18 +424,18 @@ got_huff_bits:
|
||||
copies to our buffer of decoded symbols (dbuf) now. (The last
|
||||
literal used is the one at the head of the mtfSymbol array.) */
|
||||
|
||||
if(runPos) {
|
||||
runPos=0;
|
||||
if(dbufCount+t>=dbufSize) return RETVAL_DATA_ERROR;
|
||||
if (runPos) {
|
||||
runPos = 0;
|
||||
if (dbufCount + t >= dbufSize) return RETVAL_DATA_ERROR;
|
||||
|
||||
uc = symToByte[mtfSymbol[0]];
|
||||
byteCount[uc] += t;
|
||||
while (t--) dbuf[dbufCount++]=uc;
|
||||
while (t--) dbuf[dbufCount++] = uc;
|
||||
}
|
||||
|
||||
/* Is this the terminating symbol? */
|
||||
|
||||
if(nextSym>symTotal) break;
|
||||
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
|
||||
@ -436,7 +445,7 @@ got_huff_bits:
|
||||
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;
|
||||
if (dbufCount >= dbufSize) return RETVAL_DATA_ERROR;
|
||||
i = nextSym - 1;
|
||||
uc = mtfSymbol[i];
|
||||
|
||||
@ -449,18 +458,18 @@ got_huff_bits:
|
||||
mtfSymbol[i] = mtfSymbol[i-1];
|
||||
} while (--i);
|
||||
mtfSymbol[0] = uc;
|
||||
uc=symToByte[uc];
|
||||
uc = symToByte[uc];
|
||||
|
||||
/* We have our literal byte. Save it into dbuf. */
|
||||
|
||||
byteCount[uc]++;
|
||||
dbuf[dbufCount++] = (unsigned int)uc;
|
||||
dbuf[dbufCount++] = (unsigned)uc;
|
||||
|
||||
/* Skip group initialization if we're not done with this group. Done
|
||||
* this way to avoid compiler warning. */
|
||||
|
||||
end_of_huffman_loop:
|
||||
if(symCount--) goto continue_this_group;
|
||||
end_of_huffman_loop:
|
||||
if (symCount--) goto continue_this_group;
|
||||
}
|
||||
|
||||
/* At this point, we've read all the Huffman-coded symbols (and repeated
|
||||
@ -472,17 +481,17 @@ end_of_huffman_loop:
|
||||
|
||||
/* Turn byteCount into cumulative occurrence counts of 0 to n-1. */
|
||||
|
||||
j=0;
|
||||
for (i=0;i<256;i++) {
|
||||
k=j+byteCount[i];
|
||||
j = 0;
|
||||
for (i = 0; i < 256; i++) {
|
||||
k = j + byteCount[i];
|
||||
byteCount[i] = j;
|
||||
j=k;
|
||||
j = k;
|
||||
}
|
||||
|
||||
/* Figure out what order dbuf would be in if we sorted it. */
|
||||
|
||||
for (i=0;i<dbufCount;i++) {
|
||||
uc=(unsigned char)(dbuf[i] & 0xff);
|
||||
for (i = 0; i < dbufCount; i++) {
|
||||
uc = (unsigned char)(dbuf[i] & 0xff);
|
||||
dbuf[byteCount[uc]] |= (i << 8);
|
||||
byteCount[uc]++;
|
||||
}
|
||||
@ -491,14 +500,14 @@ end_of_huffman_loop:
|
||||
doesn't get output, and if the first three characters are identical
|
||||
it doesn't qualify as a run (hence writeRunCountdown=5). */
|
||||
|
||||
if(dbufCount) {
|
||||
if(origPtr>=dbufCount) return RETVAL_DATA_ERROR;
|
||||
bd->writePos=dbuf[origPtr];
|
||||
bd->writeCurrent=(unsigned char)(bd->writePos&0xff);
|
||||
bd->writePos>>=8;
|
||||
bd->writeRunCountdown=5;
|
||||
if (dbufCount) {
|
||||
if (origPtr >= dbufCount) return RETVAL_DATA_ERROR;
|
||||
bd->writePos = dbuf[origPtr];
|
||||
bd->writeCurrent = (unsigned char)(bd->writePos & 0xff);
|
||||
bd->writePos >>= 8;
|
||||
bd->writeRunCountdown = 5;
|
||||
}
|
||||
bd->writeCount=dbufCount;
|
||||
bd->writeCount = dbufCount;
|
||||
|
||||
return RETVAL_OK;
|
||||
}
|
||||
@ -512,16 +521,16 @@ end_of_huffman_loop:
|
||||
|
||||
static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
|
||||
{
|
||||
const unsigned int *dbuf;
|
||||
int pos,current,previous,gotcount;
|
||||
const unsigned *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;
|
||||
if (bd->writeCount < 0) return bd->writeCount;
|
||||
|
||||
gotcount = 0;
|
||||
dbuf=bd->dbuf;
|
||||
pos=bd->writePos;
|
||||
current=bd->writeCurrent;
|
||||
dbuf = bd->dbuf;
|
||||
pos = bd->writePos;
|
||||
current = bd->writeCurrent;
|
||||
|
||||
/* 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
|
||||
@ -539,9 +548,9 @@ static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
|
||||
|
||||
/* If the output buffer is full, snapshot state and return */
|
||||
|
||||
if(gotcount >= len) {
|
||||
bd->writePos=pos;
|
||||
bd->writeCurrent=current;
|
||||
if (gotcount >= len) {
|
||||
bd->writePos =pos;
|
||||
bd->writeCurrent = current;
|
||||
bd->writeCopies++;
|
||||
return len;
|
||||
}
|
||||
@ -549,8 +558,8 @@ static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
|
||||
/* Write next byte into output buffer, updating CRC */
|
||||
|
||||
outbuf[gotcount++] = current;
|
||||
bd->writeCRC=(((bd->writeCRC)<<8)
|
||||
^bd->crc32Table[((bd->writeCRC)>>24)^current]);
|
||||
bd->writeCRC = (bd->writeCRC << 8)
|
||||
^ bd->crc32Table[(bd->writeCRC >> 24) ^ current];
|
||||
|
||||
/* Loop now if we're outputting multiple copies of this byte */
|
||||
|
||||
@ -558,31 +567,32 @@ static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
|
||||
--bd->writeCopies;
|
||||
continue;
|
||||
}
|
||||
decode_next_byte:
|
||||
decode_next_byte:
|
||||
if (!bd->writeCount--) break;
|
||||
/* Follow sequence vector to undo Burrows-Wheeler transform */
|
||||
previous=current;
|
||||
pos=dbuf[pos];
|
||||
current=pos&0xff;
|
||||
pos>>=8;
|
||||
previous = current;
|
||||
pos = dbuf[pos];
|
||||
current = pos & 0xff;
|
||||
pos >>= 8;
|
||||
|
||||
/* 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;
|
||||
if (--bd->writeRunCountdown) {
|
||||
if (current != previous)
|
||||
bd->writeRunCountdown = 4;
|
||||
} else {
|
||||
|
||||
/* We have a repeated run, this byte indicates the count */
|
||||
|
||||
bd->writeCopies=current;
|
||||
current=previous;
|
||||
bd->writeRunCountdown=5;
|
||||
bd->writeCopies = current;
|
||||
current = previous;
|
||||
bd->writeRunCountdown = 5;
|
||||
|
||||
/* Sometimes there are just 3 bytes (run length 0) */
|
||||
|
||||
if(!bd->writeCopies) goto decode_next_byte;
|
||||
if (!bd->writeCopies) goto decode_next_byte;
|
||||
|
||||
/* Subtract the 1 copy we'd output anyway to get extras */
|
||||
|
||||
@ -592,13 +602,13 @@ decode_next_byte:
|
||||
|
||||
/* Decompression of this block completed successfully */
|
||||
|
||||
bd->writeCRC=~bd->writeCRC;
|
||||
bd->totalCRC=((bd->totalCRC<<1) | (bd->totalCRC>>31)) ^ bd->writeCRC;
|
||||
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;
|
||||
if (bd->writeCRC != bd->headerCRC) {
|
||||
bd->totalCRC = bd->headerCRC+1;
|
||||
return RETVAL_LAST_BLOCK;
|
||||
}
|
||||
}
|
||||
@ -606,14 +616,14 @@ decode_next_byte:
|
||||
/* Refill the intermediate buffer by Huffman-decoding next block of input */
|
||||
/* (previous is just a convenient unused temp variable here) */
|
||||
|
||||
previous=get_next_block(bd);
|
||||
if(previous) {
|
||||
bd->writeCount=previous;
|
||||
return (previous!=RETVAL_LAST_BLOCK) ? previous : gotcount;
|
||||
previous = get_next_block(bd);
|
||||
if (previous) {
|
||||
bd->writeCount = previous;
|
||||
return (previous != RETVAL_LAST_BLOCK) ? previous : gotcount;
|
||||
}
|
||||
bd->writeCRC=~0;
|
||||
pos=bd->writePos;
|
||||
current=bd->writeCurrent;
|
||||
bd->writeCRC = ~0;
|
||||
pos = bd->writePos;
|
||||
current = bd->writeCurrent;
|
||||
goto decode_next_byte;
|
||||
}
|
||||
|
||||
@ -625,25 +635,28 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
|
||||
int len)
|
||||
{
|
||||
bunzip_data *bd;
|
||||
unsigned int i;
|
||||
const unsigned int BZh0=(((unsigned int)'B')<<24)+(((unsigned int)'Z')<<16)
|
||||
+(((unsigned int)'h')<<8)+(unsigned int)'0';
|
||||
unsigned i;
|
||||
enum {
|
||||
BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0'
|
||||
};
|
||||
|
||||
/* Figure out how much data to allocate */
|
||||
|
||||
i=sizeof(bunzip_data);
|
||||
if(in_fd!=-1) i+=IOBUF_SIZE;
|
||||
i = sizeof(bunzip_data);
|
||||
if (in_fd != -1) i += IOBUF_SIZE;
|
||||
|
||||
/* Allocate bunzip_data. Most fields initialize to zero. */
|
||||
|
||||
bd=*bdp=xzalloc(i);
|
||||
bd = *bdp = xzalloc(i);
|
||||
|
||||
/* Setup input buffer */
|
||||
|
||||
if(-1==(bd->in_fd=in_fd)) {
|
||||
bd->inbuf=inbuf;
|
||||
bd->inbufCount=len;
|
||||
} else bd->inbuf=(unsigned char *)(bd+1);
|
||||
bd->in_fd = in_fd;
|
||||
if (-1 == in_fd) {
|
||||
bd->inbuf = inbuf;
|
||||
bd->inbufCount = len;
|
||||
} else
|
||||
bd->inbuf = (unsigned char *)(bd + 1);
|
||||
|
||||
/* Init the CRC32 table (big endian) */
|
||||
|
||||
@ -651,20 +664,20 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
|
||||
|
||||
/* Setup for I/O error handling via longjmp */
|
||||
|
||||
i=setjmp(bd->jmpbuf);
|
||||
if(i) return i;
|
||||
i = setjmp(bd->jmpbuf);
|
||||
if (i) return i;
|
||||
|
||||
/* 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;
|
||||
i = get_bits(bd, 32);
|
||||
if (((unsigned)(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);
|
||||
bd->dbufSize = 100000 * (i - BZh0);
|
||||
|
||||
bd->dbuf=xmalloc(bd->dbufSize * sizeof(int));
|
||||
bd->dbuf = xmalloc(bd->dbufSize * sizeof(int));
|
||||
return RETVAL_OK;
|
||||
}
|
||||
|
||||
@ -679,13 +692,14 @@ uncompressStream(int src_fd, int dst_fd)
|
||||
bunzip_data *bd;
|
||||
int i;
|
||||
|
||||
outbuf=xmalloc(IOBUF_SIZE);
|
||||
i=start_bunzip(&bd,src_fd,0,0);
|
||||
if(!i) {
|
||||
outbuf = xmalloc(IOBUF_SIZE);
|
||||
i = start_bunzip(&bd, src_fd, 0, 0);
|
||||
if (!i) {
|
||||
for (;;) {
|
||||
if((i=read_bunzip(bd,outbuf,IOBUF_SIZE)) <= 0) break;
|
||||
if(i!=write(dst_fd,outbuf,i)) {
|
||||
i=RETVAL_UNEXPECTED_OUTPUT_EOF;
|
||||
i = read_bunzip(bd, outbuf, IOBUF_SIZE);
|
||||
if (i <= 0) break;
|
||||
if (i != safe_write(dst_fd, outbuf, i)) {
|
||||
i = RETVAL_UNEXPECTED_OUTPUT_EOF;
|
||||
break;
|
||||
}
|
||||
USE_DESKTOP(total_written += i;)
|
||||
@ -694,13 +708,13 @@ uncompressStream(int src_fd, int dst_fd)
|
||||
|
||||
/* Check CRC and release memory */
|
||||
|
||||
if(i==RETVAL_LAST_BLOCK) {
|
||||
if (bd->headerCRC!=bd->totalCRC) {
|
||||
if (i == RETVAL_LAST_BLOCK) {
|
||||
if (bd->headerCRC != bd->totalCRC) {
|
||||
bb_error_msg("data integrity error when decompressing");
|
||||
} else {
|
||||
i=RETVAL_OK;
|
||||
i = RETVAL_OK;
|
||||
}
|
||||
} else if (i==RETVAL_UNEXPECTED_OUTPUT_EOF) {
|
||||
} else if (i == RETVAL_UNEXPECTED_OUTPUT_EOF) {
|
||||
bb_error_msg("compressed file ends unexpectedly");
|
||||
} else {
|
||||
bb_error_msg("decompression failed");
|
||||
@ -714,18 +728,22 @@ uncompressStream(int src_fd, int dst_fd)
|
||||
|
||||
#ifdef TESTING
|
||||
|
||||
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 i=uncompressStream(0,1);
|
||||
int i = uncompressStream(0, 1);
|
||||
char c;
|
||||
|
||||
if(i<0) fprintf(stderr,"%s\n", bunzip_errors[-i]);
|
||||
else if(read(0,&c,1)) fprintf(stderr,"Trailing garbage ignored\n");
|
||||
if (i < 0)
|
||||
fprintf(stderr,"%s\n", bunzip_errors[-i]);
|
||||
else if (read(0, &c, 1))
|
||||
fprintf(stderr,"Trailing garbage ignored\n");
|
||||
return -i;
|
||||
}
|
||||
#endif
|
||||
|
||||
Loading…
Reference in New Issue
Block a user