/*
 * bzip2 is written by Julian Seward <jseward@bzip.org>.
 * Adapted for busybox by Denys Vlasenko <vda.linux@googlemail.com>.
 * See README and LICENSE files in this directory for more information.
 */

/*-------------------------------------------------------------*/
/*--- Compression machinery (not incl block sorting)        ---*/
/*---                                            compress.c ---*/
/*-------------------------------------------------------------*/

/* ------------------------------------------------------------------
This file is part of bzip2/libbzip2, a program and library for
lossless, block-sorting data compression.

bzip2/libbzip2 version 1.0.4 of 20 December 2006
Copyright (C) 1996-2006 Julian Seward <jseward@bzip.org>

Please read the WARNING, DISCLAIMER and PATENTS sections in the
README file.

This program is released under the terms of the license contained
in the file LICENSE.
------------------------------------------------------------------ */

/* CHANGES
 * 0.9.0    -- original version.
 * 0.9.0a/b -- no changes in this file.
 * 0.9.0c   -- changed setting of nGroups in sendMTFValues()
 *             so as to do a bit better on small files
*/

/* #include "bzlib_private.h" */

/*---------------------------------------------------*/
/*--- Bit stream I/O                              ---*/
/*---------------------------------------------------*/

/*---------------------------------------------------*/
static
void BZ2_bsInitWrite(EState* s)
{
        s->bsLive = 0;
        s->bsBuff = 0;
}


/*---------------------------------------------------*/
static NOINLINE
void bsFinishWrite(EState* s)
{
        while (s->bsLive > 0) {
                s->zbits[s->numZ] = (uint8_t)(s->bsBuff >> 24);
                s->numZ++;
                s->bsBuff <<= 8;
                s->bsLive -= 8;
        }
}


/*---------------------------------------------------*/
static
/* Helps only on level 5, on other levels hurts. ? */
#if CONFIG_BZIP2_FAST >= 5
ALWAYS_INLINE
#endif
void bsW(EState* s, int32_t n, uint32_t v)
{
        while (s->bsLive >= 8) {
                s->zbits[s->numZ] = (uint8_t)(s->bsBuff >> 24);
                s->numZ++;
                s->bsBuff <<= 8;
                s->bsLive -= 8;
        }
        s->bsBuff |= (v << (32 - s->bsLive - n));
        s->bsLive += n;
}


/*---------------------------------------------------*/
static
void bsPutU32(EState* s, unsigned u)
{
        bsW(s, 8, (u >> 24) & 0xff);
        bsW(s, 8, (u >> 16) & 0xff);
        bsW(s, 8, (u >>  8) & 0xff);
        bsW(s, 8,  u        & 0xff);
}


/*---------------------------------------------------*/
static
void bsPutU16(EState* s, unsigned u)
{
        bsW(s, 8, (u >>  8) & 0xff);
        bsW(s, 8,  u        & 0xff);
}


/*---------------------------------------------------*/
/*--- The back end proper                         ---*/
/*---------------------------------------------------*/

/*---------------------------------------------------*/
static
void makeMaps_e(EState* s)
{
        int i;
        s->nInUse = 0;
        for (i = 0; i < 256; i++) {
                if (s->inUse[i]) {
                        s->unseqToSeq[i] = s->nInUse;
                        s->nInUse++;
                }
        }
}


/*---------------------------------------------------*/
static NOINLINE
void generateMTFValues(EState* s)
{
        uint8_t yy[256];
        int32_t i, j;
        int32_t zPend;
        int32_t wr;
        int32_t EOB;

        /*
         * After sorting (eg, here),
         * s->arr1[0 .. s->nblock-1] holds sorted order,
         * and
         * ((uint8_t*)s->arr2)[0 .. s->nblock-1]
         * holds the original block data.
         *
         * The first thing to do is generate the MTF values,
         * and put them in ((uint16_t*)s->arr1)[0 .. s->nblock-1].
         *
         * Because there are strictly fewer or equal MTF values
         * than block values, ptr values in this area are overwritten
         * with MTF values only when they are no longer needed.
         *
         * The final compressed bitstream is generated into the
         * area starting at &((uint8_t*)s->arr2)[s->nblock]
         *
         * These storage aliases are set up in bzCompressInit(),
         * except for the last one, which is arranged in
         * compressBlock().
         */
        uint32_t* ptr   = s->ptr;
        uint8_t*  block = s->block;
        uint16_t* mtfv  = s->mtfv;

        makeMaps_e(s);
        EOB = s->nInUse+1;

        for (i = 0; i <= EOB; i++)
                s->mtfFreq[i] = 0;

        wr = 0;
        zPend = 0;
        for (i = 0; i < s->nInUse; i++)
                yy[i] = (uint8_t) i;

        for (i = 0; i < s->nblock; i++) {
                uint8_t ll_i;
                AssertD(wr <= i, "generateMTFValues(1)");
                j = ptr[i] - 1;
                if (j < 0)
                        j += s->nblock;
                ll_i = s->unseqToSeq[block[j]];
                AssertD(ll_i < s->nInUse, "generateMTFValues(2a)");

                if (yy[0] == ll_i) {
                        zPend++;
                } else {
                        if (zPend > 0) {
                                zPend--;
                                while (1) {
                                        if (zPend & 1) {
                                                mtfv[wr] = BZ_RUNB; wr++;
                                                s->mtfFreq[BZ_RUNB]++;
                                        } else {
                                                mtfv[wr] = BZ_RUNA; wr++;
                                                s->mtfFreq[BZ_RUNA]++;
                                        }
                                        if (zPend < 2) break;
                                        zPend = (uint32_t)(zPend - 2) / 2;
                                        /* bbox: unsigned div is easier */
                                };
                                zPend = 0;
                        }
                        {
                                register uint8_t  rtmp;
                                register uint8_t* ryy_j;
                                register uint8_t  rll_i;
                                rtmp  = yy[1];
                                yy[1] = yy[0];
                                ryy_j = &(yy[1]);
                                rll_i = ll_i;
                                while (rll_i != rtmp) {
                                        register uint8_t rtmp2;
                                        ryy_j++;
                                        rtmp2  = rtmp;
                                        rtmp   = *ryy_j;
                                        *ryy_j = rtmp2;
                                };
                                yy[0] = rtmp;
                                j = ryy_j - &(yy[0]);
                                mtfv[wr] = j+1;
                                wr++;
                                s->mtfFreq[j+1]++;
                        }
                }
        }

        if (zPend > 0) {
                zPend--;
                while (1) {
                        if (zPend & 1) {
                                mtfv[wr] = BZ_RUNB;
                                wr++;
                                s->mtfFreq[BZ_RUNB]++;
                        } else {
                                mtfv[wr] = BZ_RUNA;
                                wr++;
                                s->mtfFreq[BZ_RUNA]++;
                        }
                        if (zPend < 2)
                                break;
                        zPend = (uint32_t)(zPend - 2) / 2;
                        /* bbox: unsigned div is easier */
                };
                zPend = 0;
        }

        mtfv[wr] = EOB;
        wr++;
        s->mtfFreq[EOB]++;

        s->nMTF = wr;
}


/*---------------------------------------------------*/
#define BZ_LESSER_ICOST  0
#define BZ_GREATER_ICOST 15

static NOINLINE
void sendMTFValues(EState* s)
{
        int32_t v, t, i, j, gs, ge, bt, bc, iter;
        int32_t nSelectors, alphaSize, minLen, maxLen, selCtr;
        int32_t nGroups;

        /*
         * uint8_t len[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
         * is a global since the decoder also needs it.
         *
         * int32_t  code[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
         * int32_t  rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
         * are also globals only used in this proc.
         * Made global to keep stack frame size small.
         */
#define code     sendMTFValues__code
#define rfreq    sendMTFValues__rfreq
#define len_pack sendMTFValues__len_pack

        uint16_t cost[BZ_N_GROUPS];
        int32_t  fave[BZ_N_GROUPS];

        uint16_t* mtfv = s->mtfv;

        alphaSize = s->nInUse + 2;
        for (t = 0; t < BZ_N_GROUPS; t++)
                for (v = 0; v < alphaSize; v++)
                        s->len[t][v] = BZ_GREATER_ICOST;

        /*--- Decide how many coding tables to use ---*/
        AssertH(s->nMTF > 0, 3001);
        if (s->nMTF < 200)  nGroups = 2; else
        if (s->nMTF < 600)  nGroups = 3; else
        if (s->nMTF < 1200) nGroups = 4; else
        if (s->nMTF < 2400) nGroups = 5; else
        nGroups = 6;

        /*--- Generate an initial set of coding tables ---*/
        {
                int32_t nPart, remF, tFreq, aFreq;

                nPart = nGroups;
                remF  = s->nMTF;
                gs = 0;
                while (nPart > 0) {
                        tFreq = remF / nPart;
                        ge = gs - 1;
                        aFreq = 0;
                        while (aFreq < tFreq && ge < alphaSize-1) {
                                ge++;
                                aFreq += s->mtfFreq[ge];
                        }

                        if (ge > gs
                         && nPart != nGroups && nPart != 1
                         && ((nGroups - nPart) % 2 == 1) /* bbox: can this be replaced by x & 1? */
                        ) {
                                aFreq -= s->mtfFreq[ge];
                                ge--;
                        }

                        for (v = 0; v < alphaSize; v++)
                                if (v >= gs && v <= ge)
                                        s->len[nPart-1][v] = BZ_LESSER_ICOST;
                                else
                                        s->len[nPart-1][v] = BZ_GREATER_ICOST;

                        nPart--;
                        gs = ge + 1;
                        remF -= aFreq;
                }
        }

        /*
         * Iterate up to BZ_N_ITERS times to improve the tables.
         */
        for (iter = 0; iter < BZ_N_ITERS; iter++) {
                for (t = 0; t < nGroups; t++)
                        fave[t] = 0;

                for (t = 0; t < nGroups; t++)
                        for (v = 0; v < alphaSize; v++)
                                s->rfreq[t][v] = 0;

#if CONFIG_BZIP2_FAST >= 5
                /*
                 * Set up an auxiliary length table which is used to fast-track
                 * the common case (nGroups == 6).
                 */
                if (nGroups == 6) {
                        for (v = 0; v < alphaSize; v++) {
                                s->len_pack[v][0] = (s->len[1][v] << 16) | s->len[0][v];
                                s->len_pack[v][1] = (s->len[3][v] << 16) | s->len[2][v];
                                s->len_pack[v][2] = (s->len[5][v] << 16) | s->len[4][v];
                        }
                }
#endif
                nSelectors = 0;
                gs = 0;
                while (1) {
                        /*--- Set group start & end marks. --*/
                        if (gs >= s->nMTF)
                                break;
                        ge = gs + BZ_G_SIZE - 1;
                        if (ge >= s->nMTF)
                                ge = s->nMTF-1;

                        /*
                         * Calculate the cost of this group as coded
                         * by each of the coding tables.
                         */
                        for (t = 0; t < nGroups; t++)
                                cost[t] = 0;
#if CONFIG_BZIP2_FAST >= 5
                        if (nGroups == 6 && 50 == ge-gs+1) {
                                /*--- fast track the common case ---*/
                                register uint32_t cost01, cost23, cost45;
                                register uint16_t icv;
                                cost01 = cost23 = cost45 = 0;
#define BZ_ITER(nn) \
        icv = mtfv[gs+(nn)]; \
        cost01 += s->len_pack[icv][0]; \
        cost23 += s->len_pack[icv][1]; \
        cost45 += s->len_pack[icv][2];
                                BZ_ITER(0);  BZ_ITER(1);  BZ_ITER(2);  BZ_ITER(3);  BZ_ITER(4);
                                BZ_ITER(5);  BZ_ITER(6);  BZ_ITER(7);  BZ_ITER(8);  BZ_ITER(9);
                                BZ_ITER(10); BZ_ITER(11); BZ_ITER(12); BZ_ITER(13); BZ_ITER(14);
                                BZ_ITER(15); BZ_ITER(16); BZ_ITER(17); BZ_ITER(18); BZ_ITER(19);
                                BZ_ITER(20); BZ_ITER(21); BZ_ITER(22); BZ_ITER(23); BZ_ITER(24);
                                BZ_ITER(25); BZ_ITER(26); BZ_ITER(27); BZ_ITER(28); BZ_ITER(29);
                                BZ_ITER(30); BZ_ITER(31); BZ_ITER(32); BZ_ITER(33); BZ_ITER(34);
                                BZ_ITER(35); BZ_ITER(36); BZ_ITER(37); BZ_ITER(38); BZ_ITER(39);
                                BZ_ITER(40); BZ_ITER(41); BZ_ITER(42); BZ_ITER(43); BZ_ITER(44);
                                BZ_ITER(45); BZ_ITER(46); BZ_ITER(47); BZ_ITER(48); BZ_ITER(49);
#undef BZ_ITER
                                cost[0] = cost01 & 0xffff; cost[1] = cost01 >> 16;
                                cost[2] = cost23 & 0xffff; cost[3] = cost23 >> 16;
                                cost[4] = cost45 & 0xffff; cost[5] = cost45 >> 16;
                        } else
#endif
                        {
                                /*--- slow version which correctly handles all situations ---*/
                                for (i = gs; i <= ge; i++) {
                                        uint16_t icv = mtfv[i];
                                        for (t = 0; t < nGroups; t++)
                                                cost[t] += s->len[t][icv];
                                }
                        }
                        /*
                         * Find the coding table which is best for this group,
                         * and record its identity in the selector table.
                         */
                        /*bc = 999999999;*/
                        /*bt = -1;*/
                        bc = cost[0];
                        bt = 0;
                        for (t = 1 /*0*/; t < nGroups; t++) {
                                if (cost[t] < bc) {
                                        bc = cost[t];
                                        bt = t;
                                }
                        }
                        fave[bt]++;
                        s->selector[nSelectors] = bt;
                        nSelectors++;

                        /*
                         * Increment the symbol frequencies for the selected table.
                         */
/* 1% faster compress. +800 bytes */
#if CONFIG_BZIP2_FAST >= 4
                        if (nGroups == 6 && 50 == ge-gs+1) {
                                /*--- fast track the common case ---*/
#define BZ_ITUR(nn) s->rfreq[bt][mtfv[gs + (nn)]]++
                                BZ_ITUR(0);  BZ_ITUR(1);  BZ_ITUR(2);  BZ_ITUR(3);  BZ_ITUR(4);
                                BZ_ITUR(5);  BZ_ITUR(6);  BZ_ITUR(7);  BZ_ITUR(8);  BZ_ITUR(9);
                                BZ_ITUR(10); BZ_ITUR(11); BZ_ITUR(12); BZ_ITUR(13); BZ_ITUR(14);
                                BZ_ITUR(15); BZ_ITUR(16); BZ_ITUR(17); BZ_ITUR(18); BZ_ITUR(19);
                                BZ_ITUR(20); BZ_ITUR(21); BZ_ITUR(22); BZ_ITUR(23); BZ_ITUR(24);
                                BZ_ITUR(25); BZ_ITUR(26); BZ_ITUR(27); BZ_ITUR(28); BZ_ITUR(29);
                                BZ_ITUR(30); BZ_ITUR(31); BZ_ITUR(32); BZ_ITUR(33); BZ_ITUR(34);
                                BZ_ITUR(35); BZ_ITUR(36); BZ_ITUR(37); BZ_ITUR(38); BZ_ITUR(39);
                                BZ_ITUR(40); BZ_ITUR(41); BZ_ITUR(42); BZ_ITUR(43); BZ_ITUR(44);
                                BZ_ITUR(45); BZ_ITUR(46); BZ_ITUR(47); BZ_ITUR(48); BZ_ITUR(49);
#undef BZ_ITUR
                                gs = ge + 1;
                        } else
#endif
                        {
                                /*--- slow version which correctly handles all situations ---*/
                                while (gs <= ge) {
                                        s->rfreq[bt][mtfv[gs]]++;
                                        gs++;
                                }
                                /* already is: gs = ge + 1; */
                        }
                }

                /*
                 * Recompute the tables based on the accumulated frequencies.
                 */
                /* maxLen was changed from 20 to 17 in bzip2-1.0.3.  See
                 * comment in huffman.c for details. */
                for (t = 0; t < nGroups; t++)
                        BZ2_hbMakeCodeLengths(s, &(s->len[t][0]), &(s->rfreq[t][0]), alphaSize, 17 /*20*/);
        }

        AssertH(nGroups < 8, 3002);
        AssertH(nSelectors < 32768 && nSelectors <= (2 + (900000 / BZ_G_SIZE)), 3003);

        /*--- Compute MTF values for the selectors. ---*/
        {
                uint8_t pos[BZ_N_GROUPS], ll_i, tmp2, tmp;

                for (i = 0; i < nGroups; i++)
                        pos[i] = i;
                for (i = 0; i < nSelectors; i++) {
                        ll_i = s->selector[i];
                        j = 0;
                        tmp = pos[j];
                        while (ll_i != tmp) {
                                j++;
                                tmp2 = tmp;
                                tmp = pos[j];
                                pos[j] = tmp2;
                        };
                        pos[0] = tmp;
                        s->selectorMtf[i] = j;
                }
        };

        /*--- Assign actual codes for the 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];
                }
                AssertH(!(maxLen > 17 /*20*/), 3004);
                AssertH(!(minLen < 1), 3005);
                BZ2_hbAssignCodes(&(s->code[t][0]), &(s->len[t][0]), minLen, maxLen, alphaSize);
        }

        /*--- Transmit the mapping table. ---*/
        {
                /* bbox: optimized a bit more than in bzip2 */
                int inUse16 = 0;
                for (i = 0; i < 16; i++) {
                        if (sizeof(long) <= 4) {
                                inUse16 = inUse16*2 +
                                        ((*(bb__aliased_uint32_t*)&(s->inUse[i * 16 + 0])
                                        | *(bb__aliased_uint32_t*)&(s->inUse[i * 16 + 4])
                                        | *(bb__aliased_uint32_t*)&(s->inUse[i * 16 + 8])
                                        | *(bb__aliased_uint32_t*)&(s->inUse[i * 16 + 12])) != 0);
                        } else { /* Our CPU can do better */
                                inUse16 = inUse16*2 +
                                        ((*(bb__aliased_uint64_t*)&(s->inUse[i * 16 + 0])
                                        | *(bb__aliased_uint64_t*)&(s->inUse[i * 16 + 8])) != 0);
                        }
                }

                bsW(s, 16, inUse16);

                inUse16 <<= (sizeof(int)*8 - 16); /* move 15th bit into sign bit */
                for (i = 0; i < 16; i++) {
                        if (inUse16 < 0) {
                                unsigned v16 = 0;
                                for (j = 0; j < 16; j++)
                                        v16 = v16*2 + s->inUse[i * 16 + j];
                                bsW(s, 16, v16);
                        }
                        inUse16 <<= 1;
                }
        }

        /*--- Now the selectors. ---*/
        bsW(s, 3, nGroups);
        bsW(s, 15, nSelectors);
        for (i = 0; i < nSelectors; i++) {
                for (j = 0; j < s->selectorMtf[i]; j++)
                        bsW(s, 1, 1);
                bsW(s, 1, 0);
        }

        /*--- Now the coding tables. ---*/
        for (t = 0; t < nGroups; t++) {
                int32_t curr = s->len[t][0];
                bsW(s, 5, curr);
                for (i = 0; i < alphaSize; i++) {
                        while (curr < s->len[t][i]) { bsW(s, 2, 2); curr++; /* 10 */ };
                        while (curr > s->len[t][i]) { bsW(s, 2, 3); curr--; /* 11 */ };
                        bsW(s, 1, 0);
                }
        }

        /*--- And finally, the block data proper ---*/
        selCtr = 0;
        gs = 0;
        while (1) {
                if (gs >= s->nMTF)
                        break;
                ge = gs + BZ_G_SIZE - 1;
                if (ge >= s->nMTF)
                        ge = s->nMTF-1;
                AssertH(s->selector[selCtr] < nGroups, 3006);

/* Costs 1300 bytes and is _slower_ (on Intel Core 2) */
#if 0
                if (nGroups == 6 && 50 == ge-gs+1) {
                        /*--- fast track the common case ---*/
                        uint16_t mtfv_i;
                        uint8_t* s_len_sel_selCtr  = &(s->len[s->selector[selCtr]][0]);
                        int32_t* s_code_sel_selCtr = &(s->code[s->selector[selCtr]][0]);
#define BZ_ITAH(nn) \
        mtfv_i = mtfv[gs+(nn)]; \
        bsW(s, s_len_sel_selCtr[mtfv_i], s_code_sel_selCtr[mtfv_i])
                        BZ_ITAH(0);  BZ_ITAH(1);  BZ_ITAH(2);  BZ_ITAH(3);  BZ_ITAH(4);
                        BZ_ITAH(5);  BZ_ITAH(6);  BZ_ITAH(7);  BZ_ITAH(8);  BZ_ITAH(9);
                        BZ_ITAH(10); BZ_ITAH(11); BZ_ITAH(12); BZ_ITAH(13); BZ_ITAH(14);
                        BZ_ITAH(15); BZ_ITAH(16); BZ_ITAH(17); BZ_ITAH(18); BZ_ITAH(19);
                        BZ_ITAH(20); BZ_ITAH(21); BZ_ITAH(22); BZ_ITAH(23); BZ_ITAH(24);
                        BZ_ITAH(25); BZ_ITAH(26); BZ_ITAH(27); BZ_ITAH(28); BZ_ITAH(29);
                        BZ_ITAH(30); BZ_ITAH(31); BZ_ITAH(32); BZ_ITAH(33); BZ_ITAH(34);
                        BZ_ITAH(35); BZ_ITAH(36); BZ_ITAH(37); BZ_ITAH(38); BZ_ITAH(39);
                        BZ_ITAH(40); BZ_ITAH(41); BZ_ITAH(42); BZ_ITAH(43); BZ_ITAH(44);
                        BZ_ITAH(45); BZ_ITAH(46); BZ_ITAH(47); BZ_ITAH(48); BZ_ITAH(49);
#undef BZ_ITAH
                        gs = ge+1;
                } else
#endif
                {
                        /*--- slow version which correctly handles all situations ---*/
                        /* code is bit bigger, but moves multiply out of the loop */
                        uint8_t* s_len_sel_selCtr  = &(s->len [s->selector[selCtr]][0]);
                        int32_t* s_code_sel_selCtr = &(s->code[s->selector[selCtr]][0]);
                        while (gs <= ge) {
                                bsW(s,
                                        s_len_sel_selCtr[mtfv[gs]],
                                        s_code_sel_selCtr[mtfv[gs]]
                                );
                                gs++;
                        }
                        /* already is: gs = ge+1; */
                }
                selCtr++;
        }
        AssertH(selCtr == nSelectors, 3007);
#undef code
#undef rfreq
#undef len_pack
}


/*---------------------------------------------------*/
static
void BZ2_compressBlock(EState* s, int is_last_block)
{
        if (s->nblock > 0) {
                BZ_FINALISE_CRC(s->blockCRC);
                s->combinedCRC = (s->combinedCRC << 1) | (s->combinedCRC >> 31);
                s->combinedCRC ^= s->blockCRC;
                if (s->blockNo > 1)
                        s->numZ = 0;

                BZ2_blockSort(s);
        }

        s->zbits = &((uint8_t*)s->arr2)[s->nblock];

        /*-- If this is the first block, create the stream header. --*/
        if (s->blockNo == 1) {
                BZ2_bsInitWrite(s);
                /*bsPutU8(s, BZ_HDR_B);*/
                /*bsPutU8(s, BZ_HDR_Z);*/
                /*bsPutU8(s, BZ_HDR_h);*/
                /*bsPutU8(s, BZ_HDR_0 + s->blockSize100k);*/
                bsPutU32(s, BZ_HDR_BZh0 + s->blockSize100k);
        }

        if (s->nblock > 0) {
                /*bsPutU8(s, 0x31);*/
                /*bsPutU8(s, 0x41);*/
                /*bsPutU8(s, 0x59);*/
                /*bsPutU8(s, 0x26);*/
                bsPutU32(s, 0x31415926);
                /*bsPutU8(s, 0x53);*/
                /*bsPutU8(s, 0x59);*/
                bsPutU16(s, 0x5359);

                /*-- Now the block's CRC, so it is in a known place. --*/
                bsPutU32(s, s->blockCRC);

                /*
                 * Now a single bit indicating (non-)randomisation.
                 * As of version 0.9.5, we use a better sorting algorithm
                 * which makes randomisation unnecessary.  So always set
                 * the randomised bit to 'no'.  Of course, the decoder
                 * still needs to be able to handle randomised blocks
                 * so as to maintain backwards compatibility with
                 * older versions of bzip2.
                 */
                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) {
                /*bsPutU8(s, 0x17);*/
                /*bsPutU8(s, 0x72);*/
                /*bsPutU8(s, 0x45);*/
                /*bsPutU8(s, 0x38);*/
                bsPutU32(s, 0x17724538);
                /*bsPutU8(s, 0x50);*/
                /*bsPutU8(s, 0x90);*/
                bsPutU16(s, 0x5090);
                bsPutU32(s, s->combinedCRC);
                bsFinishWrite(s);
        }
}


/*-------------------------------------------------------------*/
/*--- end                                        compress.c ---*/
/*-------------------------------------------------------------*/