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hush/archival/bz/compress.c
Denis Vlasenko ef3aabe906 bzip2: size reduction, to just below 9k.
2007-10-14 00:43:01 +00:00

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/*
* 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 = (zPend - 2) / 2;
};
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 = (zPend - 2) / 2;
};
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.
*/
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)
) {
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->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);
}
/*---------------------------------------------------*/
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 ---*/
/*-------------------------------------------------------------*/
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