emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

bunzip2: big style cleanup. No code changes apart from one s/write/safe_write/

Browse Source 
(verified with objdump).
This commit is contained in:
Denis Vlasenko 2007-04-10 17:16:33 +00:00
parent a9d7d24e1f
commit b38cf3ff8a
1 changed files with 208 additions and 190 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
archival/libunarchive/decompress_bunzip2.c
View File

@ -71,7 +71,7 @@ typedef struct {
int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/; int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/;
unsigned char *inbuf /*,*outbuf*/; unsigned char *inbuf /*,*outbuf*/;
unsigned int inbufBitCount, inbufBits; unsigned inbufBitCount, inbufBits;
/* The CRC values stored in the block header and calculated from the data */ /* The CRC values stored in the block header and calculated from the data */
@ -79,7 +79,7 @@ typedef struct {
uint32_t *crc32Table; uint32_t *crc32Table;
/* Intermediate buffer and its size (in bytes) */ /* Intermediate buffer and its size (in bytes) */
unsigned int *dbuf, dbufSize; unsigned *dbuf, dbufSize;
/* These things are a bit too big to go on the stack */ /* These things are a bit too big to go on the stack */
@ -94,9 +94,9 @@ typedef struct {
/* Return the next nnn bits of input. All reads from the compressed input /* Return the next nnn bits of input. All reads from the compressed input
are done through this function. All reads are big endian */ are done through this function. All reads are big endian */
static unsigned int get_bits(bunzip_data *bd, char bits_wanted) static unsigned get_bits(bunzip_data *bd, char bits_wanted)
{ {
unsigned int bits=0; unsigned bits = 0;
/* If we need to get more data from the byte buffer, do so. (Loop getting /* 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.) */ one byte at a time to enforce endianness and avoid unaligned access.) */
@ -106,7 +106,8 @@ static unsigned int get_bits(bunzip_data *bd, char bits_wanted)
/* If we need to read more data from file into byte buffer, do so */ /* If we need to read more data from file into byte buffer, do so */
if (bd->inbufPos == bd->inbufCount) { if (bd->inbufPos == bd->inbufCount) {
if((bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE)) <= 0) bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE);
if (bd->inbufCount <= 0)
longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF); longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF);
bd->inbufPos = 0; bd->inbufPos = 0;
} }
@ -142,7 +143,7 @@ static int get_next_block(bunzip_data *bd)
int dbufCount, nextSym, dbufSize, groupCount, *base, *limit, selector, int dbufCount, nextSym, dbufSize, groupCount, *base, *limit, selector,
i, j, k, t, runPos, symCount, symTotal, nSelectors, byteCount[256]; i, j, k, t, runPos, symCount, symTotal, nSelectors, byteCount[256];
unsigned char uc, symToByte[256], mtfSymbol[256], *selectors; unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;
unsigned int *dbuf,origPtr; unsigned *dbuf, origPtr;
dbuf = bd->dbuf; dbuf = bd->dbuf;
dbufSize = bd->dbufSize; dbufSize = bd->dbufSize;
@ -167,7 +168,8 @@ static int get_next_block(bunzip_data *bd)
it didn't actually work. */ it didn't actually work. */
if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT; if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT;
if ((origPtr=get_bits(bd,24)) > dbufSize) return RETVAL_DATA_ERROR; origPtr = get_bits(bd, 24);
if (origPtr > dbufSize) return RETVAL_DATA_ERROR;
/* mapping table: if some byte values are never used (encoding things /* mapping table: if some byte values are never used (encoding things
like ascii text), the compression code removes the gaps to have fewer like ascii text), the compression code removes the gaps to have fewer
@ -181,27 +183,31 @@ static int get_next_block(bunzip_data *bd)
if (t & (1 << (15-i))) { if (t & (1 << (15-i))) {
k = get_bits(bd, 16); k = get_bits(bd, 16);
for (j = 0; j < 16; j++) for (j = 0; j < 16; j++)
if(k&(1<<(15-j))) symToByte[symTotal++]=(16*i)+j; if (k & (1 << (15-j)))
symToByte[symTotal++] = (16*i) + j;
} }
} }
/* How many different Huffman coding groups does this block use? */ /* How many different Huffman coding groups does this block use? */
groupCount = get_bits(bd, 3); groupCount = get_bits(bd, 3);
if (groupCount<2 || groupCount>MAX_GROUPS) return RETVAL_DATA_ERROR; if (groupCount < 2 || groupCount > MAX_GROUPS)
return RETVAL_DATA_ERROR;
/* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding /* 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 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 bit runs. (MTF=Move To Front, as each value is used it's moved to the
start of the list.) */ start of the list.) */
if(!(nSelectors=get_bits(bd, 15))) return RETVAL_DATA_ERROR; nSelectors = get_bits(bd, 15);
if (!nSelectors) return RETVAL_DATA_ERROR;
for (i = 0; i < groupCount; i++) mtfSymbol[i] = i; for (i = 0; i < groupCount; i++) mtfSymbol[i] = i;
for (i = 0; i < nSelectors; i++) { for (i = 0; i < nSelectors; i++) {
/* Get next value */ /* Get next value */
for (j=0;get_bits(bd,1);j++) if (j>=groupCount) return RETVAL_DATA_ERROR; for (j = 0; get_bits(bd, 1); j++)
if (j>=groupCount) return RETVAL_DATA_ERROR;
/* Decode MTF to get the next selector */ /* Decode MTF to get the next selector */
@ -228,7 +234,7 @@ static int get_next_block(bunzip_data *bd)
t = get_bits(bd, 5) - 1; t = get_bits(bd, 5) - 1;
for (i = 0; i < symCount; i++) { for (i = 0; i < symCount; i++) {
for (;;) { for (;;) {
if (((unsigned)t) > (MAX_HUFCODE_BITS-1)) if ((unsigned)t > (MAX_HUFCODE_BITS-1))
return RETVAL_DATA_ERROR; return RETVAL_DATA_ERROR;
/* If first bit is 0, stop. Else second bit indicates whether /* If first bit is 0, stop. Else second bit indicates whether
@ -287,7 +293,8 @@ static int get_next_block(bunzip_data *bd)
for (i = minLen; i <= maxLen; i++) { for (i = minLen; i <= maxLen; i++) {
temp[i] = limit[i] = 0; temp[i] = limit[i] = 0;
for (t = 0; t < symCount; t++) for (t = 0; t < symCount; t++)
if(length[t]==i) hufGroup->permute[pp++] = t; if (length[t] == i)
hufGroup->permute[pp++] = t;
} }
/* Count symbols coded for at each bit length */ /* Count symbols coded for at each bit length */
@ -312,7 +319,8 @@ static int get_next_block(bunzip_data *bd)
limit[i] = (pp << (maxLen - i)) - 1; limit[i] = (pp << (maxLen - i)) - 1;
pp <<= 1; pp <<= 1;
base[i+1]=pp-(t+=temp[i]); t += temp[i];
base[i+1] = pp - t;
} }
limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */ limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */
limit[maxLen] = pp + temp[maxLen] - 1; limit[maxLen] = pp + temp[maxLen] - 1;
@ -377,9 +385,10 @@ got_huff_bits:
/* Huffman decode value to get nextSym (with bounds checking) */ /* Huffman decode value to get nextSym (with bounds checking) */
if ((i > hufGroup->maxLen) if (i > hufGroup->maxLen)
|| (((unsigned)(j=(j>>(hufGroup->maxLen-i))-base[i])) return RETVAL_DATA_ERROR;
>= MAX_SYMBOLS)) j = (j >> (hufGroup->maxLen - i)) - base[i];
if ((unsigned)j >= MAX_SYMBOLS)
return RETVAL_DATA_ERROR; return RETVAL_DATA_ERROR;
nextSym = hufGroup->permute[j]; nextSym = hufGroup->permute[j];
@ -388,7 +397,7 @@ got_huff_bits:
check if nextSym indicates a repeated run, and if so loop collecting check if nextSym indicates a repeated run, and if so loop collecting
how many times to repeat the last literal. */ how many times to repeat the last literal. */
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 this is the start of a new run, zero out counter */
@ -454,7 +463,7 @@ got_huff_bits:
/* We have our literal byte. Save it into dbuf. */ /* We have our literal byte. Save it into dbuf. */
byteCount[uc]++; byteCount[uc]++;
dbuf[dbufCount++] = (unsigned int)uc; dbuf[dbufCount++] = (unsigned)uc;
/* Skip group initialization if we're not done with this group. Done /* Skip group initialization if we're not done with this group. Done
* this way to avoid compiler warning. */ * this way to avoid compiler warning. */
@ -512,7 +521,7 @@ end_of_huffman_loop:
static int read_bunzip(bunzip_data *bd, char *outbuf, int len) static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
{ {
const unsigned int *dbuf; const unsigned *dbuf;
int pos, current, previous, gotcount; int pos, current, previous, gotcount;
/* If last read was short due to end of file, return last block now */ /* If last read was short due to end of file, return last block now */
@ -549,8 +558,8 @@ static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
/* Write next byte into output buffer, updating CRC */ /* Write next byte into output buffer, updating CRC */
outbuf[gotcount++] = current; outbuf[gotcount++] = current;
bd->writeCRC=(((bd->writeCRC)<<8) bd->writeCRC = (bd->writeCRC << 8)
^bd->crc32Table[((bd->writeCRC)>>24)^current]); ^ bd->crc32Table[(bd->writeCRC >> 24) ^ current];
/* Loop now if we're outputting multiple copies of this byte */ /* Loop now if we're outputting multiple copies of this byte */
@ -571,7 +580,8 @@ decode_next_byte:
* of counting up because testing for non-zero is faster */ * of counting up because testing for non-zero is faster */
if (--bd->writeRunCountdown) { if (--bd->writeRunCountdown) {
if(current!=previous) bd->writeRunCountdown=4; if (current != previous)
bd->writeRunCountdown = 4;
} else { } else {
/* We have a repeated run, this byte indicates the count */ /* We have a repeated run, this byte indicates the count */
@ -625,9 +635,10 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
int len) int len)
{ {
bunzip_data *bd; bunzip_data *bd;
unsigned int i; unsigned i;
const unsigned int BZh0=(((unsigned int)'B')<<24)+(((unsigned int)'Z')<<16) enum {
+(((unsigned int)'h')<<8)+(unsigned int)'0'; BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0'
};
/* Figure out how much data to allocate */ /* Figure out how much data to allocate */
@ -640,10 +651,12 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
/* Setup input buffer */ /* Setup input buffer */
if(-1==(bd->in_fd=in_fd)) { bd->in_fd = in_fd;
if (-1 == in_fd) {
bd->inbuf = inbuf; bd->inbuf = inbuf;
bd->inbufCount = len; bd->inbufCount = len;
} else bd->inbuf=(unsigned char *)(bd+1); } else
bd->inbuf = (unsigned char *)(bd + 1);
/* Init the CRC32 table (big endian) */ /* Init the CRC32 table (big endian) */
@ -657,7 +670,7 @@ static int start_bunzip(bunzip_data **bdp, int in_fd, unsigned char *inbuf,
/* Ensure that file starts with "BZh['1'-'9']." */ /* Ensure that file starts with "BZh['1'-'9']." */
i = get_bits(bd, 32); i = get_bits(bd, 32);
if (((unsigned int)(i-BZh0-1)) >= 9) return RETVAL_NOT_BZIP_DATA; if (((unsigned)(i - BZh0 - 1)) >= 9) return RETVAL_NOT_BZIP_DATA;
/* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of /* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of
uncompressed data. Allocate intermediate buffer for block. */ uncompressed data. Allocate intermediate buffer for block. */
@ -683,8 +696,9 @@ uncompressStream(int src_fd, int dst_fd)
i = start_bunzip(&bd, src_fd, 0, 0); i = start_bunzip(&bd, src_fd, 0, 0);
if (!i) { if (!i) {
for (;;) { for (;;) {
if((i=read_bunzip(bd,outbuf,IOBUF_SIZE)) <= 0) break; i = read_bunzip(bd, outbuf, IOBUF_SIZE);
if(i!=write(dst_fd,outbuf,i)) { if (i <= 0) break;
if (i != safe_write(dst_fd, outbuf, i)) {
i = RETVAL_UNEXPECTED_OUTPUT_EOF; i = RETVAL_UNEXPECTED_OUTPUT_EOF;
break; break;
} }
@ -714,9 +728,11 @@ uncompressStream(int src_fd, int dst_fd)
#ifdef TESTING #ifdef TESTING
static char * const bunzip_errors[]={NULL,"Bad file checksum","Not bzip data", static char *const bunzip_errors[] = {
NULL, "Bad file checksum", "Not bzip data",
"Unexpected input EOF", "Unexpected output EOF", "Data error", "Unexpected input EOF", "Unexpected output EOF", "Data error",
"Out of memory","Obsolete (pre 0.9.5) bzip format not supported."}; "Out of memory", "Obsolete (pre 0.9.5) bzip format not supported"
};
/* Dumb little test thing, decompress stdin to stdout */ /* Dumb little test thing, decompress stdin to stdout */
int main(int argc, char **argv) int main(int argc, char **argv)
@ -724,8 +740,10 @@ int main(int argc, char **argv)
int i = uncompressStream(0, 1); int i = uncompressStream(0, 1);
char c; char c;
if(i<0) fprintf(stderr,"%s\n", bunzip_errors[-i]); if (i < 0)
else if(read(0,&c,1)) fprintf(stderr,"Trailing garbage ignored\n"); fprintf(stderr,"%s\n", bunzip_errors[-i]);
else if (read(0, &c, 1))
fprintf(stderr,"Trailing garbage ignored\n");
return -i; return -i;
} }
#endif #endif