ref: 1d82e3f42aa82b12edba2e057c1a6cc090ee1c80
dir: /sys/src/cmd/bzip2/lib/bzdecompress.c/
/*
* THIS FILE IS NOT IDENTICAL TO THE ORIGINAL
* FROM THE BZIP2 DISTRIBUTION.
*
* It has been modified, mainly to break the library
* into smaller pieces.
*
* Russ Cox
* rsc@plan9.bell-labs.com
* July 2000
*/
/*-------------------------------------------------------------*/
/*--- Library top-level functions. ---*/
/*--- bzlib.c ---*/
/*-------------------------------------------------------------*/
/*--
This file is a part of bzip2 and/or libbzip2, a program and
library for lossless, block-sorting data compression.
Copyright (C) 1996-2000 Julian R Seward. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. The origin of this software must not be misrepresented; you must
not claim that you wrote the original software. If you use this
software in a product, an acknowledgment in the product
documentation would be appreciated but is not required.
3. Altered source versions must be plainly marked as such, and must
not be misrepresented as being the original software.
4. The name of the author may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Julian Seward, Cambridge, UK.
jseward@acm.org
bzip2/libbzip2 version 1.0 of 21 March 2000
This program is based on (at least) the work of:
Mike Burrows
David Wheeler
Peter Fenwick
Alistair Moffat
Radford Neal
Ian H. Witten
Robert Sedgewick
Jon L. Bentley
For more information on these sources, see the manual.
--*/
/*--
CHANGES
~~~~~~~
0.9.0 -- original version.
0.9.0a/b -- no changes in this file.
0.9.0c
* made zero-length BZ_FLUSH work correctly in bzCompress().
* fixed bzWrite/bzRead to ignore zero-length requests.
* fixed bzread to correctly handle read requests after EOF.
* wrong parameter order in call to bzDecompressInit in
bzBuffToBuffDecompress. Fixed.
--*/
#include "os.h"
#include "bzlib.h"
#include "bzlib_private.h"
/*---------------------------------------------------*/
/*--- Decompression stuff ---*/
/*---------------------------------------------------*/
/*---------------------------------------------------*/
int BZ_API(BZ2_bzDecompressInit)
( bz_stream* strm,
int verbosity,
int small )
{
DState* s;
if (!bz_config_ok()) return BZ_CONFIG_ERROR;
if (strm == NULL) return BZ_PARAM_ERROR;
if (small != 0 && small != 1) return BZ_PARAM_ERROR;
if (verbosity < 0 || verbosity > 4) return BZ_PARAM_ERROR;
if (strm->bzalloc == NULL) strm->bzalloc = default_bzalloc;
if (strm->bzfree == NULL) strm->bzfree = default_bzfree;
s = BZALLOC( sizeof(DState) );
if (s == NULL) return BZ_MEM_ERROR;
s->strm = strm;
strm->state = s;
s->state = BZ_X_MAGIC_1;
s->bsLive = 0;
s->bsBuff = 0;
s->calculatedCombinedCRC = 0;
strm->total_in_lo32 = 0;
strm->total_in_hi32 = 0;
strm->total_out_lo32 = 0;
strm->total_out_hi32 = 0;
s->smallDecompress = (Bool)small;
s->ll4 = NULL;
s->ll16 = NULL;
s->tt = NULL;
s->currBlockNo = 0;
s->verbosity = verbosity;
return BZ_OK;
}
/*---------------------------------------------------*/
static
void unRLE_obuf_to_output_FAST ( DState* s )
{
UChar k1;
if (s->blockRandomised) {
while (True) {
/* try to finish existing run */
while (True) {
if (s->strm->avail_out == 0) return;
if (s->state_out_len == 0) break;
*( (UChar*)(s->strm->next_out) ) = s->state_out_ch;
BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch );
s->state_out_len--;
s->strm->next_out++;
s->strm->avail_out--;
s->strm->total_out_lo32++;
if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++;
}
/* can a new run be started? */
if (s->nblock_used == s->save_nblock+1) return;
s->state_out_len = 1;
s->state_out_ch = s->k0;
BZ_GET_FAST(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
s->state_out_len = 2;
BZ_GET_FAST(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
s->state_out_len = 3;
BZ_GET_FAST(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
BZ_GET_FAST(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
s->state_out_len = ((Int32)k1) + 4;
BZ_GET_FAST(s->k0); BZ_RAND_UPD_MASK;
s->k0 ^= BZ_RAND_MASK; s->nblock_used++;
}
} else {
/* restore */
UInt32 c_calculatedBlockCRC = s->calculatedBlockCRC;
UChar c_state_out_ch = s->state_out_ch;
Int32 c_state_out_len = s->state_out_len;
Int32 c_nblock_used = s->nblock_used;
Int32 c_k0 = s->k0;
UInt32* c_tt = s->tt;
UInt32 c_tPos = s->tPos;
char* cs_next_out = s->strm->next_out;
unsigned int cs_avail_out = s->strm->avail_out;
/* end restore */
UInt32 avail_out_INIT = cs_avail_out;
Int32 s_save_nblockPP = s->save_nblock+1;
unsigned int total_out_lo32_old;
while (True) {
/* try to finish existing run */
if (c_state_out_len > 0) {
while (True) {
if (cs_avail_out == 0) goto return_notr;
if (c_state_out_len == 1) break;
*( (UChar*)(cs_next_out) ) = c_state_out_ch;
BZ_UPDATE_CRC ( c_calculatedBlockCRC, c_state_out_ch );
c_state_out_len--;
cs_next_out++;
cs_avail_out--;
}
s_state_out_len_eq_one:
{
if (cs_avail_out == 0) {
c_state_out_len = 1; goto return_notr;
};
*( (UChar*)(cs_next_out) ) = c_state_out_ch;
BZ_UPDATE_CRC ( c_calculatedBlockCRC, c_state_out_ch );
cs_next_out++;
cs_avail_out--;
}
}
/* can a new run be started? */
if (c_nblock_used == s_save_nblockPP) {
c_state_out_len = 0; goto return_notr;
};
c_state_out_ch = c_k0;
BZ_GET_FAST_C(k1); c_nblock_used++;
if (k1 != c_k0) {
c_k0 = k1; goto s_state_out_len_eq_one;
};
if (c_nblock_used == s_save_nblockPP)
goto s_state_out_len_eq_one;
c_state_out_len = 2;
BZ_GET_FAST_C(k1); c_nblock_used++;
if (c_nblock_used == s_save_nblockPP) continue;
if (k1 != c_k0) { c_k0 = k1; continue; };
c_state_out_len = 3;
BZ_GET_FAST_C(k1); c_nblock_used++;
if (c_nblock_used == s_save_nblockPP) continue;
if (k1 != c_k0) { c_k0 = k1; continue; };
BZ_GET_FAST_C(k1); c_nblock_used++;
c_state_out_len = ((Int32)k1) + 4;
BZ_GET_FAST_C(c_k0); c_nblock_used++;
}
return_notr:
total_out_lo32_old = s->strm->total_out_lo32;
s->strm->total_out_lo32 += (avail_out_INIT - cs_avail_out);
if (s->strm->total_out_lo32 < total_out_lo32_old)
s->strm->total_out_hi32++;
/* save */
s->calculatedBlockCRC = c_calculatedBlockCRC;
s->state_out_ch = c_state_out_ch;
s->state_out_len = c_state_out_len;
s->nblock_used = c_nblock_used;
s->k0 = c_k0;
s->tt = c_tt;
s->tPos = c_tPos;
s->strm->next_out = cs_next_out;
s->strm->avail_out = cs_avail_out;
/* end save */
}
}
/*---------------------------------------------------*/
__inline__ Int32 BZ2_indexIntoF ( Int32 indx, Int32 *cftab )
{
Int32 nb, na, mid;
nb = 0;
na = 256;
do {
mid = (nb + na) >> 1;
if (indx >= cftab[mid]) nb = mid; else na = mid;
}
while (na - nb != 1);
return nb;
}
/*---------------------------------------------------*/
static
void unRLE_obuf_to_output_SMALL ( DState* s )
{
UChar k1;
if (s->blockRandomised) {
while (True) {
/* try to finish existing run */
while (True) {
if (s->strm->avail_out == 0) return;
if (s->state_out_len == 0) break;
*( (UChar*)(s->strm->next_out) ) = s->state_out_ch;
BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch );
s->state_out_len--;
s->strm->next_out++;
s->strm->avail_out--;
s->strm->total_out_lo32++;
if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++;
}
/* can a new run be started? */
if (s->nblock_used == s->save_nblock+1) return;
s->state_out_len = 1;
s->state_out_ch = s->k0;
BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
s->state_out_len = 2;
BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
s->state_out_len = 3;
BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK;
k1 ^= BZ_RAND_MASK; s->nblock_used++;
s->state_out_len = ((Int32)k1) + 4;
BZ_GET_SMALL(s->k0); BZ_RAND_UPD_MASK;
s->k0 ^= BZ_RAND_MASK; s->nblock_used++;
}
} else {
while (True) {
/* try to finish existing run */
while (True) {
if (s->strm->avail_out == 0) return;
if (s->state_out_len == 0) break;
*( (UChar*)(s->strm->next_out) ) = s->state_out_ch;
BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch );
s->state_out_len--;
s->strm->next_out++;
s->strm->avail_out--;
s->strm->total_out_lo32++;
if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++;
}
/* can a new run be started? */
if (s->nblock_used == s->save_nblock+1) return;
s->state_out_len = 1;
s->state_out_ch = s->k0;
BZ_GET_SMALL(k1); s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
s->state_out_len = 2;
BZ_GET_SMALL(k1); s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
s->state_out_len = 3;
BZ_GET_SMALL(k1); s->nblock_used++;
if (s->nblock_used == s->save_nblock+1) continue;
if (k1 != s->k0) { s->k0 = k1; continue; };
BZ_GET_SMALL(k1); s->nblock_used++;
s->state_out_len = ((Int32)k1) + 4;
BZ_GET_SMALL(s->k0); s->nblock_used++;
}
}
}
/*---------------------------------------------------*/
int BZ_API(BZ2_bzDecompress) ( bz_stream *strm )
{
DState* s;
if (strm == NULL) return BZ_PARAM_ERROR;
s = strm->state;
if (s == NULL) return BZ_PARAM_ERROR;
if (s->strm != strm) return BZ_PARAM_ERROR;
while (True) {
if (s->state == BZ_X_IDLE) return BZ_SEQUENCE_ERROR;
if (s->state == BZ_X_OUTPUT) {
if (s->smallDecompress)
unRLE_obuf_to_output_SMALL ( s ); else
unRLE_obuf_to_output_FAST ( s );
if (s->nblock_used == s->save_nblock+1 && s->state_out_len == 0) {
BZ_FINALISE_CRC ( s->calculatedBlockCRC );
if (s->verbosity >= 3)
VPrintf2 ( " {0x%x, 0x%x}", s->storedBlockCRC,
s->calculatedBlockCRC );
if (s->verbosity >= 2) VPrintf0 ( "]" );
if (s->calculatedBlockCRC != s->storedBlockCRC)
return BZ_DATA_ERROR;
s->calculatedCombinedCRC
= (s->calculatedCombinedCRC << 1) |
(s->calculatedCombinedCRC >> 31);
s->calculatedCombinedCRC ^= s->calculatedBlockCRC;
s->state = BZ_X_BLKHDR_1;
} else {
return BZ_OK;
}
}
if (s->state >= BZ_X_MAGIC_1) {
Int32 r = BZ2_decompress ( s );
if (r == BZ_STREAM_END) {
if (s->verbosity >= 3)
VPrintf2 ( "\n combined CRCs: stored = 0x%x, computed = 0x%x",
s->storedCombinedCRC, s->calculatedCombinedCRC );
if (s->calculatedCombinedCRC != s->storedCombinedCRC)
return BZ_DATA_ERROR;
return r;
}
if (s->state != BZ_X_OUTPUT) return r;
}
}
}
/*---------------------------------------------------*/
int BZ_API(BZ2_bzDecompressEnd) ( bz_stream *strm )
{
DState* s;
if (strm == NULL) return BZ_PARAM_ERROR;
s = strm->state;
if (s == NULL) return BZ_PARAM_ERROR;
if (s->strm != strm) return BZ_PARAM_ERROR;
if (s->tt != NULL) BZFREE(s->tt);
if (s->ll16 != NULL) BZFREE(s->ll16);
if (s->ll4 != NULL) BZFREE(s->ll4);
BZFREE(strm->state);
strm->state = NULL;
return BZ_OK;
}