577 lines
16 KiB
C
577 lines
16 KiB
C
/* $NetBSD: compress.c,v 1.2 1998/09/14 03:08:17 ross Exp $ */
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/*-------------------------------------------------------------*/
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/*--- Compression machinery (not incl block sorting) ---*/
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/*--- compress.c ---*/
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/*-------------------------------------------------------------*/
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/*--
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This file is a part of bzip2 and/or libbzip2, a program and
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library for lossless, block-sorting data compression.
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Copyright (C) 1996-1998 Julian R Seward. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. The origin of this software must not be misrepresented; you must
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not claim that you wrote the original software. If you use this
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software in a product, an acknowledgment in the product
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documentation would be appreciated but is not required.
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3. Altered source versions must be plainly marked as such, and must
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not be misrepresented as being the original software.
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4. The name of the author may not be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Julian Seward, Guildford, Surrey, UK.
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jseward@acm.org
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bzip2/libbzip2 version 0.9.0 of 28 June 1998
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This program is based on (at least) the work of:
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Mike Burrows
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David Wheeler
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Peter Fenwick
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Alistair Moffat
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Radford Neal
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Ian H. Witten
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Robert Sedgewick
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Jon L. Bentley
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For more information on these sources, see the manual.
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--*/
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#include "bzlib_private.h"
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/*---------------------------------------------------*/
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/*--- Bit stream I/O ---*/
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/*---------------------------------------------------*/
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/*---------------------------------------------------*/
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void bsInitWrite ( EState* s )
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{
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s->bsLive = 0;
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s->bsBuff = 0;
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}
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/*---------------------------------------------------*/
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static
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void bsFinishWrite ( EState* s )
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{
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while (s->bsLive > 0) {
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((UChar*)(s->quadrant))[s->numZ] = (UChar)(s->bsBuff >> 24);
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s->numZ++;
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s->bsBuff <<= 8;
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s->bsLive -= 8;
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}
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}
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/*---------------------------------------------------*/
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#define bsNEEDW(nz) \
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{ \
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while (s->bsLive >= 8) { \
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((UChar*)(s->quadrant))[s->numZ] \
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= (UChar)(s->bsBuff >> 24); \
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s->numZ++; \
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s->bsBuff <<= 8; \
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s->bsLive -= 8; \
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} \
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}
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/*---------------------------------------------------*/
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static
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void bsW ( EState* s, Int32 n, UInt32 v )
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{
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bsNEEDW ( n );
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s->bsBuff |= (v << (32 - s->bsLive - n));
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s->bsLive += n;
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}
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/*---------------------------------------------------*/
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static
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void bsPutUInt32 ( EState* s, UInt32 u )
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{
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bsW ( s, 8, (u >> 24) & 0xffL );
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bsW ( s, 8, (u >> 16) & 0xffL );
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bsW ( s, 8, (u >> 8) & 0xffL );
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bsW ( s, 8, u & 0xffL );
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}
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/*---------------------------------------------------*/
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static
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void bsPutUChar ( EState* s, UChar c )
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{
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bsW( s, 8, (UInt32)c );
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}
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/*---------------------------------------------------*/
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/*--- The back end proper ---*/
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/*---------------------------------------------------*/
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/*---------------------------------------------------*/
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static
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void makeMaps_e ( EState* s )
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{
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Int32 i;
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s->nInUse = 0;
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for (i = 0; i < 256; i++)
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if (s->inUse[i]) {
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s->unseqToSeq[i] = s->nInUse;
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s->nInUse++;
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}
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}
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/*---------------------------------------------------*/
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static
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void generateMTFValues ( EState* s )
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{
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UChar yy[256];
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Int32 i, j;
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UChar tmp;
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UChar tmp2;
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Int32 zPend;
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Int32 wr;
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Int32 EOB;
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makeMaps_e ( s );
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EOB = s->nInUse+1;
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for (i = 0; i <= EOB; i++) s->mtfFreq[i] = 0;
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wr = 0;
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zPend = 0;
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for (i = 0; i < s->nInUse; i++) yy[i] = (UChar) i;
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for (i = 0; i < s->nblock; i++) {
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UChar ll_i;
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AssertD ( wr <= i, "generateMTFValues(1)" );
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j = s->zptr[i]-1; if (j < 0) j += s->nblock;
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ll_i = s->unseqToSeq[s->block[j]];
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AssertD ( ll_i < s->nInUse, "generateMTFValues(2a)" );
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j = 0;
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tmp = yy[j];
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while ( ll_i != tmp ) {
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j++;
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tmp2 = tmp;
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tmp = yy[j];
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yy[j] = tmp2;
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};
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yy[0] = tmp;
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if (j == 0) {
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zPend++;
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} else {
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if (zPend > 0) {
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zPend--;
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while (True) {
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switch (zPend % 2) {
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case 0: s->szptr[wr] = BZ_RUNA; wr++; s->mtfFreq[BZ_RUNA]++; break;
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case 1: s->szptr[wr] = BZ_RUNB; wr++; s->mtfFreq[BZ_RUNB]++; break;
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};
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if (zPend < 2) break;
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zPend = (zPend - 2) / 2;
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};
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zPend = 0;
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}
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s->szptr[wr] = j+1; wr++; s->mtfFreq[j+1]++;
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}
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}
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if (zPend > 0) {
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zPend--;
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while (True) {
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switch (zPend % 2) {
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case 0: s->szptr[wr] = BZ_RUNA; wr++; s->mtfFreq[BZ_RUNA]++; break;
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case 1: s->szptr[wr] = BZ_RUNB; wr++; s->mtfFreq[BZ_RUNB]++; break;
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};
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if (zPend < 2) break;
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zPend = (zPend - 2) / 2;
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};
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}
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s->szptr[wr] = EOB; wr++; s->mtfFreq[EOB]++;
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s->nMTF = wr;
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}
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/*---------------------------------------------------*/
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#define BZ_LESSER_ICOST 0
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#define BZ_GREATER_ICOST 15
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static
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void sendMTFValues ( EState* s )
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{
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Int32 v, t, i, j, gs, ge, totc, bt, bc, iter;
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Int32 nSelectors, alphaSize, minLen, maxLen, selCtr;
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Int32 nGroups, nBytes;
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/*--
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UChar len [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
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is a global since the decoder also needs it.
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Int32 code[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
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Int32 rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
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are also globals only used in this proc.
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Made global to keep stack frame size small.
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--*/
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UInt16 cost[BZ_N_GROUPS];
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Int32 fave[BZ_N_GROUPS];
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if (s->verbosity >= 3)
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VPrintf3( " %d in block, %d after MTF & 1-2 coding, "
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"%d+2 syms in use\n",
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s->nblock, s->nMTF, s->nInUse );
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alphaSize = s->nInUse+2;
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for (t = 0; t < BZ_N_GROUPS; t++)
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for (v = 0; v < alphaSize; v++)
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s->len[t][v] = BZ_GREATER_ICOST;
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/*--- Decide how many coding tables to use ---*/
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AssertH ( s->nMTF > 0, 3001 );
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if (s->nMTF < 200) nGroups = 2; else
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if (s->nMTF < 800) nGroups = 4; else
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nGroups = 6;
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/*--- Generate an initial set of coding tables ---*/
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{
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Int32 nPart, remF, tFreq, aFreq;
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nPart = nGroups;
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remF = s->nMTF;
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gs = 0;
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while (nPart > 0) {
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tFreq = remF / nPart;
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ge = gs-1;
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aFreq = 0;
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while (aFreq < tFreq && ge < alphaSize-1) {
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ge++;
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aFreq += s->mtfFreq[ge];
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}
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if (ge > gs
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&& nPart != nGroups && nPart != 1
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&& ((nGroups-nPart) % 2 == 1)) {
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aFreq -= s->mtfFreq[ge];
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ge--;
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}
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if (s->verbosity >= 3)
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VPrintf5( " initial group %d, [%d .. %d], "
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"has %d syms (%4.1f%%)\n",
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nPart, gs, ge, aFreq,
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(100.0 * (float)aFreq) / (float)(s->nMTF) );
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for (v = 0; v < alphaSize; v++)
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if (v >= gs && v <= ge)
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s->len[nPart-1][v] = BZ_LESSER_ICOST; else
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s->len[nPart-1][v] = BZ_GREATER_ICOST;
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nPart--;
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gs = ge+1;
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remF -= aFreq;
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}
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}
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/*---
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Iterate up to BZ_N_ITERS times to improve the tables.
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---*/
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for (iter = 0; iter < BZ_N_ITERS; iter++) {
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for (t = 0; t < nGroups; t++) fave[t] = 0;
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for (t = 0; t < nGroups; t++)
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for (v = 0; v < alphaSize; v++)
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s->rfreq[t][v] = 0;
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nSelectors = 0;
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totc = 0;
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gs = 0;
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while (True) {
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/*--- Set group start & end marks. --*/
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if (gs >= s->nMTF) break;
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ge = gs + BZ_G_SIZE - 1;
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if (ge >= s->nMTF) ge = s->nMTF-1;
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/*--
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Calculate the cost of this group as coded
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by each of the coding tables.
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--*/
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for (t = 0; t < nGroups; t++) cost[t] = 0;
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if (nGroups == 6) {
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register UInt16 cost0, cost1, cost2, cost3, cost4, cost5;
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cost0 = cost1 = cost2 = cost3 = cost4 = cost5 = 0;
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for (i = gs; i <= ge; i++) {
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UInt16 icv = s->szptr[i];
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cost0 += s->len[0][icv];
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cost1 += s->len[1][icv];
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cost2 += s->len[2][icv];
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cost3 += s->len[3][icv];
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cost4 += s->len[4][icv];
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cost5 += s->len[5][icv];
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}
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cost[0] = cost0; cost[1] = cost1; cost[2] = cost2;
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cost[3] = cost3; cost[4] = cost4; cost[5] = cost5;
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} else {
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for (i = gs; i <= ge; i++) {
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UInt16 icv = s->szptr[i];
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for (t = 0; t < nGroups; t++) cost[t] += s->len[t][icv];
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}
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}
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/*--
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Find the coding table which is best for this group,
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and record its identity in the selector table.
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--*/
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bc = 999999999; bt = -1;
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for (t = 0; t < nGroups; t++)
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if (cost[t] < bc) { bc = cost[t]; bt = t; };
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totc += bc;
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fave[bt]++;
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s->selector[nSelectors] = bt;
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nSelectors++;
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/*--
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Increment the symbol frequencies for the selected table.
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--*/
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for (i = gs; i <= ge; i++)
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s->rfreq[bt][ s->szptr[i] ]++;
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gs = ge+1;
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}
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if (s->verbosity >= 3) {
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VPrintf2 ( " pass %d: size is %d, grp uses are ",
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iter+1, totc/8 );
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for (t = 0; t < nGroups; t++)
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VPrintf1 ( "%d ", fave[t] );
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VPrintf0 ( "\n" );
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}
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/*--
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Recompute the tables based on the accumulated frequencies.
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--*/
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for (t = 0; t < nGroups; t++)
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hbMakeCodeLengths ( &(s->len[t][0]), &(s->rfreq[t][0]),
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alphaSize, 20 );
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}
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AssertH( nGroups < 8, 3002 );
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AssertH( nSelectors < 32768 &&
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nSelectors <= (2 + (900000 / BZ_G_SIZE)),
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3003 );
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/*--- Compute MTF values for the selectors. ---*/
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{
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UChar pos[BZ_N_GROUPS], ll_i, tmp2, tmp;
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for (i = 0; i < nGroups; i++) pos[i] = i;
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for (i = 0; i < nSelectors; i++) {
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ll_i = s->selector[i];
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j = 0;
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tmp = pos[j];
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while ( ll_i != tmp ) {
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j++;
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tmp2 = tmp;
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tmp = pos[j];
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pos[j] = tmp2;
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};
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pos[0] = tmp;
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s->selectorMtf[i] = j;
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}
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};
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/*--- Assign actual codes for the tables. --*/
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for (t = 0; t < nGroups; t++) {
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minLen = 32;
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maxLen = 0;
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for (i = 0; i < alphaSize; i++) {
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if (s->len[t][i] > maxLen) maxLen = s->len[t][i];
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if (s->len[t][i] < minLen) minLen = s->len[t][i];
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}
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AssertH ( !(maxLen > 20), 3004 );
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AssertH ( !(minLen < 1), 3005 );
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hbAssignCodes ( &(s->code[t][0]), &(s->len[t][0]),
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minLen, maxLen, alphaSize );
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}
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/*--- Transmit the mapping table. ---*/
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{
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Bool inUse16[16];
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for (i = 0; i < 16; i++) {
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inUse16[i] = False;
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for (j = 0; j < 16; j++)
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if (s->inUse[i * 16 + j]) inUse16[i] = True;
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}
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nBytes = s->numZ;
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for (i = 0; i < 16; i++)
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if (inUse16[i]) bsW(s,1,1); else bsW(s,1,0);
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for (i = 0; i < 16; i++)
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if (inUse16[i])
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for (j = 0; j < 16; j++) {
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if (s->inUse[i * 16 + j]) bsW(s,1,1); else bsW(s,1,0);
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}
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if (s->verbosity >= 3)
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VPrintf1( " bytes: mapping %d, ", s->numZ-nBytes );
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}
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/*--- Now the selectors. ---*/
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nBytes = s->numZ;
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bsW ( s, 3, nGroups );
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bsW ( s, 15, nSelectors );
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for (i = 0; i < nSelectors; i++) {
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for (j = 0; j < s->selectorMtf[i]; j++) bsW(s,1,1);
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bsW(s,1,0);
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}
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if (s->verbosity >= 3)
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VPrintf1( "selectors %d, ", s->numZ-nBytes );
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/*--- Now the coding tables. ---*/
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nBytes = s->numZ;
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for (t = 0; t < nGroups; t++) {
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Int32 curr = s->len[t][0];
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bsW ( s, 5, curr );
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for (i = 0; i < alphaSize; i++) {
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while (curr < s->len[t][i]) { bsW(s,2,2); curr++; /* 10 */ };
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while (curr > s->len[t][i]) { bsW(s,2,3); curr--; /* 11 */ };
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bsW ( s, 1, 0 );
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}
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}
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if (s->verbosity >= 3)
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VPrintf1 ( "code lengths %d, ", s->numZ-nBytes );
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/*--- And finally, the block data proper ---*/
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nBytes = s->numZ;
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selCtr = 0;
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gs = 0;
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while (True) {
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if (gs >= s->nMTF) break;
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ge = gs + BZ_G_SIZE - 1;
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if (ge >= s->nMTF) ge = s->nMTF-1;
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for (i = gs; i <= ge; i++) {
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AssertH ( s->selector[selCtr] < nGroups, 3006 );
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bsW ( s,
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s->len [s->selector[selCtr]] [s->szptr[i]],
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s->code [s->selector[selCtr]] [s->szptr[i]] );
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}
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gs = ge+1;
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selCtr++;
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}
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AssertH( selCtr == nSelectors, 3007 );
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if (s->verbosity >= 3)
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VPrintf1( "codes %d\n", s->numZ-nBytes );
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}
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/*---------------------------------------------------*/
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void compressBlock ( EState* s, Bool is_last_block )
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{
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if (s->nblock > 0) {
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BZ_FINALISE_CRC ( s->blockCRC );
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s->combinedCRC = (s->combinedCRC << 1) | (s->combinedCRC >> 31);
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s->combinedCRC ^= s->blockCRC;
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if (s->blockNo > 1) s->numZ = 0;
|
|
|
|
if (s->verbosity >= 2)
|
|
VPrintf4( " block %d: crc = 0x%8x, "
|
|
"combined CRC = 0x%8x, size = %d\n",
|
|
s->blockNo, s->blockCRC, s->combinedCRC, s->nblock );
|
|
|
|
blockSort ( s );
|
|
}
|
|
|
|
/*-- If this is the first block, create the stream header. --*/
|
|
if (s->blockNo == 1) {
|
|
bsInitWrite ( s );
|
|
bsPutUChar ( s, 'B' );
|
|
bsPutUChar ( s, 'Z' );
|
|
bsPutUChar ( s, 'h' );
|
|
bsPutUChar ( s, '0' + s->blockSize100k );
|
|
}
|
|
|
|
if (s->nblock > 0) {
|
|
|
|
bsPutUChar ( s, 0x31 ); bsPutUChar ( s, 0x41 );
|
|
bsPutUChar ( s, 0x59 ); bsPutUChar ( s, 0x26 );
|
|
bsPutUChar ( s, 0x53 ); bsPutUChar ( s, 0x59 );
|
|
|
|
/*-- Now the block's CRC, so it is in a known place. --*/
|
|
bsPutUInt32 ( s, s->blockCRC );
|
|
|
|
/*-- Now a single bit indicating randomisation. --*/
|
|
if (s->blockRandomised) {
|
|
bsW(s,1,1); s->nBlocksRandomised++;
|
|
} else
|
|
bsW(s,1,0);
|
|
|
|
bsW ( s, 24, s->origPtr );
|
|
generateMTFValues ( s );
|
|
sendMTFValues ( s );
|
|
}
|
|
|
|
|
|
/*-- If this is the last block, add the stream trailer. --*/
|
|
if (is_last_block) {
|
|
|
|
if (s->verbosity >= 2 && s->nBlocksRandomised > 0)
|
|
VPrintf2 ( " %d block%s needed randomisation\n",
|
|
s->nBlocksRandomised,
|
|
s->nBlocksRandomised == 1 ? "" : "s" );
|
|
|
|
bsPutUChar ( s, 0x17 ); bsPutUChar ( s, 0x72 );
|
|
bsPutUChar ( s, 0x45 ); bsPutUChar ( s, 0x38 );
|
|
bsPutUChar ( s, 0x50 ); bsPutUChar ( s, 0x90 );
|
|
bsPutUInt32 ( s, s->combinedCRC );
|
|
if (s->verbosity >= 2)
|
|
VPrintf1( " final combined CRC = 0x%x\n ", s->combinedCRC );
|
|
bsFinishWrite ( s );
|
|
}
|
|
}
|
|
|
|
|
|
/*-------------------------------------------------------------*/
|
|
/*--- end compress.c ---*/
|
|
/*-------------------------------------------------------------*/
|