ref: 493994826396340fed0afd048e642ca747a5997a
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 * [email protected] * 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. [email protected] 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; }