archival/bz/compress.c - codeaurora/busybox - Gitiles

 /*
  * 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_FEATURE_SPEED >= 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, totc, bt, bc, iter;
 	int32_t nSelectors, alphaSize, minLen, maxLen, selCtr;
 	int32_t nGroups, nBytes;

 	/*
 	 * 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_FEATURE_SPEED >= 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;
 		totc = 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_FEATURE_SPEED >= 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;
 				}
 			}
 			totc += bc;
 			fave[bt]++;
 			s->selector[nSelectors] = bt;
 			nSelectors++;

 			/*
 			 * Increment the symbol frequencies for the selected table.
 			 */
 /* 1% faster compress. +800 bytes */
 #if CONFIG_BZIP2_FEATURE_SPEED >= 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 +
 					((*(uint32_t*)&(s->inUse[i * 16 + 0])
 					| *(uint32_t*)&(s->inUse[i * 16 + 4])
 					| *(uint32_t*)&(s->inUse[i * 16 + 8])
 					| *(uint32_t*)&(s->inUse[i * 16 + 12])) != 0);
 			} else { /* Our CPU can do better */
 				inUse16 = inUse16*2 +
 					((*(uint64_t*)&(s->inUse[i * 16 + 0])
 					| *(uint64_t*)&(s->inUse[i * 16 + 8])) != 0);
 			}
 		}

 		nBytes = s->numZ;
 		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. ---*/
 	nBytes = s->numZ;
 	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. ---*/
 	nBytes = s->numZ;

 	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 ---*/
 	nBytes = s->numZ;
 	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 ---*/
 /*-------------------------------------------------------------*/
	/*
	* 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_FEATURE_SPEED >= 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, totc, bt, bc, iter;
	int32_t nSelectors, alphaSize, minLen, maxLen, selCtr;
	int32_t nGroups, nBytes;

	/*
	* 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_FEATURE_SPEED >= 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;
	totc = 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_FEATURE_SPEED >= 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;
	}
	}
	totc += bc;
	fave[bt]++;
	s->selector[nSelectors] = bt;
	nSelectors++;

	/*
	* Increment the symbol frequencies for the selected table.
	*/
	/* 1% faster compress. +800 bytes */
	#if CONFIG_BZIP2_FEATURE_SPEED >= 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 +
	(((uint32_t)&(s->inUse[i * 16 + 0])
	\| (uint32_t)&(s->inUse[i * 16 + 4])
	\| (uint32_t)&(s->inUse[i * 16 + 8])
	\| (uint32_t)&(s->inUse[i * 16 + 12])) != 0);
	} else { /* Our CPU can do better */
	inUse16 = inUse16*2 +
	(((uint64_t)&(s->inUse[i * 16 + 0])
	\| (uint64_t)&(s->inUse[i * 16 + 8])) != 0);
	}
	}

	nBytes = s->numZ;
	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 = v162 + s->inUse[i 16 + j];
	bsW(s, 16, v16);
	}
	inUse16 <<= 1;
	}
	}

	/--- Now the selectors. ---/
	nBytes = s->numZ;
	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. ---/
	nBytes = s->numZ;

	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 ---/
	nBytes = s->numZ;
	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 ---/
	/-------------------------------------------------------------/