ref: 13785bbbef60f5c13aa973c1e7d4277aa55f6a2d
dir: /sys/src/cmd/bzip2/lib/decompress.c/
/*-------------------------------------------------------------*/ /*--- Decompression machinery ---*/ /*--- decompress.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. --*/ #include "os.h" #include "bzlib.h" #include "bzlib_private.h" /*---------------------------------------------------*/ static void makeMaps_d ( DState* s ) { Int32 i; s->nInUse = 0; for (i = 0; i < 256; i++) if (s->inUse[i]) { s->seqToUnseq[s->nInUse] = i; s->nInUse++; } } /*---------------------------------------------------*/ #define RETURN(rrr) \ { retVal = rrr; goto save_state_and_return; }; #define GET_BITS(lll,vvv,nnn) \ case lll: s->state = lll; \ while (True) { \ if (s->bsLive >= nnn) { \ UInt32 v; \ v = (s->bsBuff >> \ (s->bsLive-nnn)) & ((1 << nnn)-1); \ s->bsLive -= nnn; \ vvv = v; \ break; \ } \ if (s->strm->avail_in == 0) RETURN(BZ_OK); \ s->bsBuff \ = (s->bsBuff << 8) | \ ((UInt32) \ (*((UChar*)(s->strm->next_in)))); \ s->bsLive += 8; \ s->strm->next_in++; \ s->strm->avail_in--; \ s->strm->total_in_lo32++; \ if (s->strm->total_in_lo32 == 0) \ s->strm->total_in_hi32++; \ } #define GET_UCHAR(lll,uuu) \ GET_BITS(lll,uuu,8) #define GET_BIT(lll,uuu) \ GET_BITS(lll,uuu,1) /*---------------------------------------------------*/ #define GET_MTF_VAL(label1,label2,lval) \ { \ if (groupPos == 0) { \ groupNo++; \ if (groupNo >= nSelectors) \ RETURN(BZ_DATA_ERROR); \ groupPos = BZ_G_SIZE; \ gSel = s->selector[groupNo]; \ gMinlen = s->minLens[gSel]; \ gLimit = &(s->limit[gSel][0]); \ gPerm = &(s->perm[gSel][0]); \ gBase = &(s->base[gSel][0]); \ } \ groupPos--; \ zn = gMinlen; \ GET_BITS(label1, zvec, zn); \ while (1) { \ if (zn > 20 /* the longest code */) \ RETURN(BZ_DATA_ERROR); \ if (zvec <= gLimit[zn]) break; \ zn++; \ GET_BIT(label2, zj); \ zvec = (zvec << 1) | zj; \ }; \ if (zvec - gBase[zn] < 0 \ || zvec - gBase[zn] >= BZ_MAX_ALPHA_SIZE) \ RETURN(BZ_DATA_ERROR); \ lval = gPerm[zvec - gBase[zn]]; \ } /*---------------------------------------------------*/ Int32 BZ2_decompress ( DState* s ) { UChar uc; Int32 retVal; Int32 minLen, maxLen; bz_stream* strm = s->strm; /* stuff that needs to be saved/restored */ Int32 i; Int32 j; Int32 t; Int32 alphaSize; Int32 nGroups; Int32 nSelectors; Int32 EOB; Int32 groupNo; Int32 groupPos; Int32 nextSym; Int32 nblockMAX; Int32 nblock; Int32 es; Int32 N; Int32 curr; Int32 zt; Int32 zn; Int32 zvec; Int32 zj; Int32 gSel; Int32 gMinlen; Int32* gLimit; Int32* gBase; Int32* gPerm; if (s->state == BZ_X_MAGIC_1) { /*initialise the save area*/ s->save_i = 0; s->save_j = 0; s->save_t = 0; s->save_alphaSize = 0; s->save_nGroups = 0; s->save_nSelectors = 0; s->save_EOB = 0; s->save_groupNo = 0; s->save_groupPos = 0; s->save_nextSym = 0; s->save_nblockMAX = 0; s->save_nblock = 0; s->save_es = 0; s->save_N = 0; s->save_curr = 0; s->save_zt = 0; s->save_zn = 0; s->save_zvec = 0; s->save_zj = 0; s->save_gSel = 0; s->save_gMinlen = 0; s->save_gLimit = NULL; s->save_gBase = NULL; s->save_gPerm = NULL; } /*restore from the save area*/ i = s->save_i; j = s->save_j; t = s->save_t; alphaSize = s->save_alphaSize; nGroups = s->save_nGroups; nSelectors = s->save_nSelectors; EOB = s->save_EOB; groupNo = s->save_groupNo; groupPos = s->save_groupPos; nextSym = s->save_nextSym; nblockMAX = s->save_nblockMAX; nblock = s->save_nblock; es = s->save_es; N = s->save_N; curr = s->save_curr; zt = s->save_zt; zn = s->save_zn; zvec = s->save_zvec; zj = s->save_zj; gSel = s->save_gSel; gMinlen = s->save_gMinlen; gLimit = s->save_gLimit; gBase = s->save_gBase; gPerm = s->save_gPerm; retVal = BZ_OK; switch (s->state) { GET_UCHAR(BZ_X_MAGIC_1, uc); if (uc != 'B') RETURN(BZ_DATA_ERROR_MAGIC); GET_UCHAR(BZ_X_MAGIC_2, uc); if (uc != 'Z') RETURN(BZ_DATA_ERROR_MAGIC); GET_UCHAR(BZ_X_MAGIC_3, uc) if (uc != 'h') RETURN(BZ_DATA_ERROR_MAGIC); GET_BITS(BZ_X_MAGIC_4, s->blockSize100k, 8) if (s->blockSize100k < '1' || s->blockSize100k > '9') RETURN(BZ_DATA_ERROR_MAGIC); s->blockSize100k -= '0'; if (s->smallDecompress) { s->ll16 = BZALLOC( s->blockSize100k * 100000 * sizeof(UInt16) ); s->ll4 = BZALLOC( ((1 + s->blockSize100k * 100000) >> 1) * sizeof(UChar) ); if (s->ll16 == NULL || s->ll4 == NULL) RETURN(BZ_MEM_ERROR); } else { s->tt = BZALLOC( s->blockSize100k * 100000 * sizeof(Int32) ); if (s->tt == NULL) RETURN(BZ_MEM_ERROR); } GET_UCHAR(BZ_X_BLKHDR_1, uc); if (uc == 0x17) goto endhdr_2; if (uc != 0x31) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_BLKHDR_2, uc); if (uc != 0x41) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_BLKHDR_3, uc); if (uc != 0x59) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_BLKHDR_4, uc); if (uc != 0x26) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_BLKHDR_5, uc); if (uc != 0x53) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_BLKHDR_6, uc); if (uc != 0x59) RETURN(BZ_DATA_ERROR); s->currBlockNo++; if (s->verbosity >= 2) VPrintf1 ( "\n [%d: huff+mtf ", s->currBlockNo ); s->storedBlockCRC = 0; GET_UCHAR(BZ_X_BCRC_1, uc); s->storedBlockCRC = (s->storedBlockCRC << 8) | ((UInt32)uc); GET_UCHAR(BZ_X_BCRC_2, uc); s->storedBlockCRC = (s->storedBlockCRC << 8) | ((UInt32)uc); GET_UCHAR(BZ_X_BCRC_3, uc); s->storedBlockCRC = (s->storedBlockCRC << 8) | ((UInt32)uc); GET_UCHAR(BZ_X_BCRC_4, uc); s->storedBlockCRC = (s->storedBlockCRC << 8) | ((UInt32)uc); GET_BITS(BZ_X_RANDBIT, s->blockRandomised, 1); s->origPtr = 0; GET_UCHAR(BZ_X_ORIGPTR_1, uc); s->origPtr = (s->origPtr << 8) | ((Int32)uc); GET_UCHAR(BZ_X_ORIGPTR_2, uc); s->origPtr = (s->origPtr << 8) | ((Int32)uc); GET_UCHAR(BZ_X_ORIGPTR_3, uc); s->origPtr = (s->origPtr << 8) | ((Int32)uc); if (s->origPtr < 0) RETURN(BZ_DATA_ERROR); if (s->origPtr > 10 + 100000*s->blockSize100k) RETURN(BZ_DATA_ERROR); /*--- Receive the mapping table ---*/ for (i = 0; i < 16; i++) { GET_BIT(BZ_X_MAPPING_1, uc); if (uc == 1) s->inUse16[i] = True; else s->inUse16[i] = False; } for (i = 0; i < 256; i++) s->inUse[i] = False; for (i = 0; i < 16; i++) if (s->inUse16[i]) for (j = 0; j < 16; j++) { GET_BIT(BZ_X_MAPPING_2, uc); if (uc == 1) s->inUse[i * 16 + j] = True; } makeMaps_d ( s ); if (s->nInUse == 0) RETURN(BZ_DATA_ERROR); alphaSize = s->nInUse+2; /*--- Now the selectors ---*/ GET_BITS(BZ_X_SELECTOR_1, nGroups, 3); if (nGroups < 2 || nGroups > 6) RETURN(BZ_DATA_ERROR); GET_BITS(BZ_X_SELECTOR_2, nSelectors, 15); if (nSelectors < 1) RETURN(BZ_DATA_ERROR); for (i = 0; i < nSelectors; i++) { j = 0; while (True) { GET_BIT(BZ_X_SELECTOR_3, uc); if (uc == 0) break; j++; if (j >= nGroups) RETURN(BZ_DATA_ERROR); } s->selectorMtf[i] = j; } /*--- Undo the MTF values for the selectors. ---*/ { UChar pos[BZ_N_GROUPS], tmp, v; for (v = 0; v < nGroups; v++) pos[v] = v; for (i = 0; i < nSelectors; i++) { v = s->selectorMtf[i]; tmp = pos[v]; while (v > 0) { pos[v] = pos[v-1]; v--; } pos[0] = tmp; s->selector[i] = tmp; } } /*--- Now the coding tables ---*/ for (t = 0; t < nGroups; t++) { GET_BITS(BZ_X_CODING_1, curr, 5); for (i = 0; i < alphaSize; i++) { while (True) { if (curr < 1 || curr > 20) RETURN(BZ_DATA_ERROR); GET_BIT(BZ_X_CODING_2, uc); if (uc == 0) break; GET_BIT(BZ_X_CODING_3, uc); if (uc == 0) curr++; else curr--; } s->len[t][i] = curr; } } /*--- Create the Huffman decoding tables ---*/ for (t = 0; t < nGroups; t++) { minLen = 32; maxLen = 0; for (i = 0; i < alphaSize; i++) { if (s->len[t][i] > maxLen) maxLen = s->len[t][i]; if (s->len[t][i] < minLen) minLen = s->len[t][i]; } BZ2_hbCreateDecodeTables ( &(s->limit[t][0]), &(s->base[t][0]), &(s->perm[t][0]), &(s->len[t][0]), minLen, maxLen, alphaSize ); s->minLens[t] = minLen; } /*--- Now the MTF values ---*/ EOB = s->nInUse+1; nblockMAX = 100000 * s->blockSize100k; groupNo = -1; groupPos = 0; for (i = 0; i <= 255; i++) s->unzftab[i] = 0; /*-- MTF init --*/ { Int32 ii, jj, kk; kk = MTFA_SIZE-1; for (ii = 256 / MTFL_SIZE - 1; ii >= 0; ii--) { for (jj = MTFL_SIZE-1; jj >= 0; jj--) { s->mtfa[kk] = (UChar)(ii * MTFL_SIZE + jj); kk--; } s->mtfbase[ii] = kk + 1; } } /*-- end MTF init --*/ nblock = 0; GET_MTF_VAL(BZ_X_MTF_1, BZ_X_MTF_2, nextSym); while (True) { if (nextSym == EOB) break; if (nextSym == BZ_RUNA || nextSym == BZ_RUNB) { es = -1; N = 1; do { if (nextSym == BZ_RUNA) es = es + (0+1) * N; else if (nextSym == BZ_RUNB) es = es + (1+1) * N; N = N * 2; GET_MTF_VAL(BZ_X_MTF_3, BZ_X_MTF_4, nextSym); } while (nextSym == BZ_RUNA || nextSym == BZ_RUNB); es++; uc = s->seqToUnseq[ s->mtfa[s->mtfbase[0]] ]; s->unzftab[uc] += es; if (s->smallDecompress) while (es > 0) { if (nblock >= nblockMAX) RETURN(BZ_DATA_ERROR); s->ll16[nblock] = (UInt16)uc; nblock++; es--; } else while (es > 0) { if (nblock >= nblockMAX) RETURN(BZ_DATA_ERROR); s->tt[nblock] = (UInt32)uc; nblock++; es--; }; continue; } else { if (nblock >= nblockMAX) RETURN(BZ_DATA_ERROR); /*-- uc = MTF ( nextSym-1 ) --*/ { Int32 ii, jj, kk, pp, lno, off; UInt32 nn; nn = (UInt32)(nextSym - 1); if (nn < MTFL_SIZE) { /* avoid general-case expense */ pp = s->mtfbase[0]; uc = s->mtfa[pp+nn]; while (nn > 3) { Int32 z = pp+nn; s->mtfa[(z) ] = s->mtfa[(z)-1]; s->mtfa[(z)-1] = s->mtfa[(z)-2]; s->mtfa[(z)-2] = s->mtfa[(z)-3]; s->mtfa[(z)-3] = s->mtfa[(z)-4]; nn -= 4; } while (nn > 0) { s->mtfa[(pp+nn)] = s->mtfa[(pp+nn)-1]; nn--; }; s->mtfa[pp] = uc; } else { /* general case */ lno = nn / MTFL_SIZE; off = nn % MTFL_SIZE; pp = s->mtfbase[lno] + off; uc = s->mtfa[pp]; while (pp > s->mtfbase[lno]) { s->mtfa[pp] = s->mtfa[pp-1]; pp--; }; s->mtfbase[lno]++; while (lno > 0) { s->mtfbase[lno]--; s->mtfa[s->mtfbase[lno]] = s->mtfa[s->mtfbase[lno-1] + MTFL_SIZE - 1]; lno--; } s->mtfbase[0]--; s->mtfa[s->mtfbase[0]] = uc; if (s->mtfbase[0] == 0) { kk = MTFA_SIZE-1; for (ii = 256 / MTFL_SIZE-1; ii >= 0; ii--) { for (jj = MTFL_SIZE-1; jj >= 0; jj--) { s->mtfa[kk] = s->mtfa[s->mtfbase[ii] + jj]; kk--; } s->mtfbase[ii] = kk + 1; } } } } /*-- end uc = MTF ( nextSym-1 ) --*/ s->unzftab[s->seqToUnseq[uc]]++; if (s->smallDecompress) s->ll16[nblock] = (UInt16)(s->seqToUnseq[uc]); else s->tt[nblock] = (UInt32)(s->seqToUnseq[uc]); nblock++; GET_MTF_VAL(BZ_X_MTF_5, BZ_X_MTF_6, nextSym); continue; } } /* Now we know what nblock is, we can do a better sanity check on s->origPtr. */ if (s->origPtr < 0 || s->origPtr >= nblock) RETURN(BZ_DATA_ERROR); s->state_out_len = 0; s->state_out_ch = 0; BZ_INITIALISE_CRC ( s->calculatedBlockCRC ); s->state = BZ_X_OUTPUT; if (s->verbosity >= 2) VPrintf0 ( "rt+rld" ); /*-- Set up cftab to facilitate generation of T^(-1) --*/ s->cftab[0] = 0; for (i = 1; i <= 256; i++) s->cftab[i] = s->unzftab[i-1]; for (i = 1; i <= 256; i++) s->cftab[i] += s->cftab[i-1]; if (s->smallDecompress) { /*-- Make a copy of cftab, used in generation of T --*/ for (i = 0; i <= 256; i++) s->cftabCopy[i] = s->cftab[i]; /*-- compute the T vector --*/ for (i = 0; i < nblock; i++) { uc = (UChar)(s->ll16[i]); SET_LL(i, s->cftabCopy[uc]); s->cftabCopy[uc]++; } /*-- Compute T^(-1) by pointer reversal on T --*/ i = s->origPtr; j = GET_LL(i); do { Int32 tmp = GET_LL(j); SET_LL(j, i); i = j; j = tmp; } while (i != s->origPtr); s->tPos = s->origPtr; s->nblock_used = 0; if (s->blockRandomised) { BZ_RAND_INIT_MASK; BZ_GET_SMALL(s->k0); s->nblock_used++; BZ_RAND_UPD_MASK; s->k0 ^= BZ_RAND_MASK; } else { BZ_GET_SMALL(s->k0); s->nblock_used++; } } else { /*-- compute the T^(-1) vector --*/ for (i = 0; i < nblock; i++) { uc = (UChar)(s->tt[i] & 0xff); s->tt[s->cftab[uc]] |= (i << 8); s->cftab[uc]++; } s->tPos = s->tt[s->origPtr] >> 8; s->nblock_used = 0; if (s->blockRandomised) { BZ_RAND_INIT_MASK; BZ_GET_FAST(s->k0); s->nblock_used++; BZ_RAND_UPD_MASK; s->k0 ^= BZ_RAND_MASK; } else { BZ_GET_FAST(s->k0); s->nblock_used++; } } RETURN(BZ_OK); endhdr_2: GET_UCHAR(BZ_X_ENDHDR_2, uc); if (uc != 0x72) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_ENDHDR_3, uc); if (uc != 0x45) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_ENDHDR_4, uc); if (uc != 0x38) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_ENDHDR_5, uc); if (uc != 0x50) RETURN(BZ_DATA_ERROR); GET_UCHAR(BZ_X_ENDHDR_6, uc); if (uc != 0x90) RETURN(BZ_DATA_ERROR); s->storedCombinedCRC = 0; GET_UCHAR(BZ_X_CCRC_1, uc); s->storedCombinedCRC = (s->storedCombinedCRC << 8) | ((UInt32)uc); GET_UCHAR(BZ_X_CCRC_2, uc); s->storedCombinedCRC = (s->storedCombinedCRC << 8) | ((UInt32)uc); GET_UCHAR(BZ_X_CCRC_3, uc); s->storedCombinedCRC = (s->storedCombinedCRC << 8) | ((UInt32)uc); GET_UCHAR(BZ_X_CCRC_4, uc); s->storedCombinedCRC = (s->storedCombinedCRC << 8) | ((UInt32)uc); s->state = BZ_X_IDLE; RETURN(BZ_STREAM_END); default: AssertH ( False, 4001 ); } AssertH ( False, 4002 ); save_state_and_return: s->save_i = i; s->save_j = j; s->save_t = t; s->save_alphaSize = alphaSize; s->save_nGroups = nGroups; s->save_nSelectors = nSelectors; s->save_EOB = EOB; s->save_groupNo = groupNo; s->save_groupPos = groupPos; s->save_nextSym = nextSym; s->save_nblockMAX = nblockMAX; s->save_nblock = nblock; s->save_es = es; s->save_N = N; s->save_curr = curr; s->save_zt = zt; s->save_zn = zn; s->save_zvec = zvec; s->save_zj = zj; s->save_gSel = gSel; s->save_gMinlen = gMinlen; s->save_gLimit = gLimit; s->save_gBase = gBase; s->save_gPerm = gPerm; return retVal; } /*-------------------------------------------------------------*/ /*--- end decompress.c ---*/ /*-------------------------------------------------------------*/