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NetBSD/usr.bin/window/compress.c

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/*
* Copyright (c) 1989 Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Edward Wang at The University of California, Berkeley.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
/*static char sccsid[] = "from: @(#)compress.c 3.6 (Berkeley) 8/12/90";*/
static char rcsid[] = "$Id: compress.c,v 1.2 1993/08/01 18:02:23 mycroft Exp $";
#endif /* not lint */
#include "ww.h"
#include "tt.h"
/* special */
#include <stdio.h>
int cc_trace = 0;
FILE *cc_trace_fp;
/* tunable parameters */
int cc_reverse = 1;
int cc_sort = 0;
int cc_chop = 0;
int cc_token_max = 8; /* <= TOKEN_MAX */
int cc_token_min = 2; /* > tt.tt_put_token_cost */
int cc_npass0 = 1;
int cc_npass1 = 1;
int cc_bufsize = 1024 * 3; /* XXX, or 80 * 24 * 2 */
int cc_ntoken = 8192;
#define cc_weight XXX
#ifndef cc_weight
int cc_weight = 0;
#endif
#define TOKEN_MAX 16
struct cc {
char string[TOKEN_MAX];
char length;
char flag;
#ifndef cc_weight
short weight;
#endif
long time; /* time last seen */
short bcount; /* count in this buffer */
short ccount; /* count in compression */
short places; /* places in the buffer */
short code; /* token code */
struct cc *qforw, *qback;
struct cc *hforw, **hback;
};
short cc_thresholds[TOKEN_MAX + 1];
#define thresh(length) (cc_thresholds[length])
#define threshp(code, count, length) \
((code) >= 0 || (short) (count) >= cc_thresholds[length])
#ifndef cc_weight
short cc_wthresholds[TOKEN_MAX + 1];
#define wthresh(length) (cc_wthresholds[length])
#define wthreshp(weight, length) ((short) (weight) >= cc_wthresholds[length])
#else
#define wthreshp(weight, length) (0)
#endif
#ifndef cc_weight
short cc_wlimits[TOKEN_MAX + 1];
#define wlimit(length) (cc_wlimits[length])
#endif
#define put_token_score(length) ((length) - tt.tt_put_token_cost)
int cc_score_adjustments[TOKEN_MAX + 1][8]; /* XXX, 8 > max of cc_thresholds */
#define score_adjust(score, p) \
do { \
int length = (p)->length; \
int ccount = (p)->ccount; \
if (threshp((p)->code, ccount, length) || \
wthreshp((p)->weight, length)) /* XXX */ \
(score) -= length - tt.tt_put_token_cost; \
else \
(score) += cc_score_adjustments[length][ccount]; \
} while (0)
int cc_initial_scores[TOKEN_MAX + 1][8]; /* XXX, 8 > max of cc_thresholds */
struct cc cc_q0a, cc_q0b, cc_q1a, cc_q1b;
#define qinsert(p1, p2) \
do { \
register struct cc *forw = (p1)->qforw; \
register struct cc *back = (p1)->qback; \
back->qforw = forw; \
forw->qback = back; \
forw = (p2)->qforw; \
(p1)->qforw = forw; \
forw->qback = (p1); \
(p2)->qforw = (p1); \
(p1)->qback = (p2); \
} while (0)
#define qinsertq(q, p) \
((q)->qforw == (q) ? 0 : \
((q)->qback->qforw = (p)->qforw, \
(p)->qforw->qback = (q)->qback, \
(q)->qforw->qback = (p), \
(p)->qforw = (q)->qforw, \
(q)->qforw = (q), \
(q)->qback = (q)))
#define H (14)
#define HSIZE (1 << H)
#define hash(h, c) ((((h) >> H - 8 | (h) << 8) ^ (c)) & HSIZE - 1)
char *cc_buffer;
struct cc **cc_output; /* the output array */
short *cc_places[TOKEN_MAX + 1];
short *cc_hashcodes; /* for computing hashcodes */
struct cc **cc_htab; /* the hash table */
struct cc **cc_tokens; /* holds all the active tokens */
struct cc_undo {
struct cc **pos;
struct cc *val;
} *cc_undo;
long cc_time, cc_time0;
char *cc_tt_ob, *cc_tt_obe;
ccinit()
{
register i, j;
register struct cc *p;
if (tt.tt_token_max > cc_token_max)
tt.tt_token_max = cc_token_max;
if (tt.tt_token_min < cc_token_min)
tt.tt_token_min = cc_token_min;
if (tt.tt_token_min > tt.tt_token_max) {
tt.tt_ntoken = 0;
return 0;
}
if (tt.tt_ntoken > cc_ntoken / 2) /* not likely */
tt.tt_ntoken = cc_ntoken / 2;
#define C(x) (sizeof (x) / sizeof *(x))
for (i = 0; i < C(cc_thresholds); i++) {
int h = i - tt.tt_put_token_cost;
if (h > 0)
cc_thresholds[i] =
(tt.tt_set_token_cost + 1 + h - 1) / h + 1;
else
cc_thresholds[i] = 0;
}
for (i = 0; i < C(cc_score_adjustments); i++) {
int t = cc_thresholds[i];
for (j = 0; j < C(*cc_score_adjustments); j++) {
if (j >= t)
cc_score_adjustments[i][j] =
- (i - tt.tt_put_token_cost);
else if (j < t - 1)
cc_score_adjustments[i][j] = 0;
else
/*
* cost now is
* length * (ccount + 1) a
* cost before was
* set-token-cost + length +
* ccount * put-token-cost b
* the score adjustment is (b - a)
*/
cc_score_adjustments[i][j] =
tt.tt_set_token_cost + i +
j * tt.tt_put_token_cost -
i * (j + 1);
if (j >= t)
cc_initial_scores[i][j] = 0;
else
/*
* - (set-token-cost +
* (length - put-token-cost) -
* (length - put-token-cost) * ccount)
*/
cc_initial_scores[i][j] =
- (tt.tt_set_token_cost +
(i - tt.tt_put_token_cost) -
(i - tt.tt_put_token_cost) * j);
}
}
#ifndef cc_weight
for (i = 1; i < C(cc_wthresholds); i++) {
cc_wthresholds[i] =
((tt.tt_set_token_cost + tt.tt_put_token_cost) / i +
i / 5 + 1) *
cc_weight + 1;
cc_wlimits[i] = cc_wthresholds[i] + cc_weight;
}
#endif
#undef C
if ((cc_output = (struct cc **)
malloc((unsigned) cc_bufsize * sizeof *cc_output)) == 0)
goto nomem;
if ((cc_hashcodes = (short *)
malloc((unsigned) cc_bufsize * sizeof *cc_hashcodes)) == 0)
goto nomem;
if ((cc_htab = (struct cc **) malloc(HSIZE * sizeof *cc_htab)) == 0)
goto nomem;
if ((cc_tokens = (struct cc **)
malloc((unsigned)
(cc_ntoken + tt.tt_token_max - tt.tt_token_min + 1) *
sizeof *cc_tokens)) == 0)
goto nomem;
if ((cc_undo = (struct cc_undo *)
malloc((unsigned) cc_bufsize * sizeof *cc_undo)) == 0)
goto nomem;
for (i = tt.tt_token_min; i <= tt.tt_token_max; i++)
if ((cc_places[i] = (short *)
malloc((unsigned) cc_bufsize * sizeof **cc_places)) == 0)
goto nomem;
cc_q0a.qforw = cc_q0a.qback = &cc_q0a;
cc_q0b.qforw = cc_q0b.qback = &cc_q0b;
cc_q1a.qforw = cc_q1a.qback = &cc_q1a;
cc_q1b.qforw = cc_q1b.qback = &cc_q1b;
if ((p = (struct cc *) malloc((unsigned) cc_ntoken * sizeof *p)) == 0)
goto nomem;
for (i = 0; i < tt.tt_ntoken; i++) {
p->code = i;
p->time = -1;
p->qback = cc_q0a.qback;
p->qforw = &cc_q0a;
p->qback->qforw = p;
cc_q0a.qback = p;
p++;
}
for (; i < cc_ntoken; i++) {
p->code = -1;
p->time = -1;
p->qback = cc_q1a.qback;
p->qforw = &cc_q1a;
p->qback->qforw = p;
cc_q1a.qback = p;
p++;
}
cc_tt_ob = tt_ob;
cc_tt_obe = tt_obe;
if ((cc_buffer = malloc((unsigned) cc_bufsize)) == 0)
goto nomem;
return 0;
nomem:
wwerrno = WWE_NOMEM;
return -1;
}
ccstart()
{
register struct cc *p;
int ccflush();
(*tt.tt_flush)();
tt_obp = tt_ob = cc_buffer;
tt_obe = tt_ob + cc_bufsize;
tt.tt_flush = ccflush;
bzero((char *) cc_htab, HSIZE * sizeof *cc_htab);
for (p = cc_q0a.qforw; p != &cc_q0a; p = p->qforw)
p->hback = 0;
for (p = cc_q1a.qforw; p != &cc_q1a; p = p->qforw)
p->hback = 0;
if (cc_trace)
cc_trace_fp = fopen("window-trace", "a");
}
ccend()
{
int ttflush();
(*tt.tt_flush)();
tt_obp = tt_ob = cc_tt_ob;
tt_obe = cc_tt_obe;
tt.tt_flush = ttflush;
if (cc_trace_fp != NULL) {
(void) fclose(cc_trace_fp);
cc_trace_fp = NULL;
}
}
ccflush()
{
int bufsize = tt_obp - tt_ob;
int n;
int ttflush();
if (tt_ob != cc_buffer)
abort();
if (cc_trace_fp != NULL) {
(void) fwrite(tt_ob, 1, bufsize, cc_trace_fp);
putc(-1, cc_trace_fp);
}
if (bufsize < tt.tt_token_min) {
ttflush();
return;
}
tt_obp = tt_ob = cc_tt_ob;
tt_obe = cc_tt_obe;
tt.tt_flush = ttflush;
cc_time0 = cc_time;
cc_time += bufsize;
n = cc_sweep_phase(cc_buffer, bufsize, cc_tokens);
cc_compress_phase(cc_output, bufsize, cc_tokens, n);
cc_output_phase(cc_buffer, cc_output, bufsize);
ttflush();
tt_obp = tt_ob = cc_buffer;
tt_obe = cc_buffer + cc_bufsize;
tt.tt_flush = ccflush;
}
cc_sweep_phase(buffer, bufsize, tokens)
char *buffer;
struct cc **tokens;
{
register struct cc **pp = tokens;
register i, n;
#ifdef STATS
int nn, ii;
#endif
#ifdef STATS
if (verbose >= 0)
time_begin();
if (verbose > 0)
printf("Sweep:");
#endif
cc_sweep0(buffer, bufsize, tt.tt_token_min - 1);
#ifdef STATS
ntoken_stat = 0;
nn = 0;
ii = 0;
#endif
for (i = tt.tt_token_min; i <= tt.tt_token_max; i++) {
#ifdef STATS
if (verbose > 0) {
if (ii > 7) {
printf("\n ");
ii = 0;
}
ii++;
printf(" (%d", i);
(void) fflush(stdout);
}
#endif
n = cc_sweep(buffer, bufsize, pp, i);
pp += n;
#ifdef STATS
if (verbose > 0) {
if (--n > 0) {
printf(" %d", n);
nn += n;
}
putchar(')');
}
#endif
}
qinsertq(&cc_q1b, &cc_q1a);
#ifdef STATS
if (verbose > 0)
printf("\n %d tokens, %d candidates\n",
ntoken_stat, nn);
if (verbose >= 0)
time_end();
#endif
return pp - tokens;
}
cc_sweep0(buffer, n, length)
char *buffer;
{
register char *p;
register short *hc;
register i;
register short c;
register short pc = tt.tt_padc;
/* n and length are at least 1 */
p = buffer++;
hc = cc_hashcodes;
i = n;
do {
if ((*hc++ = *p++) == pc)
hc[-1] = -1;
} while (--i);
while (--length) {
p = buffer++;
hc = cc_hashcodes;
for (i = n--; --i;) {
if ((c = *p++) == pc || *hc < 0)
c = -1;
else
c = hash(*hc, c);
*hc++ = c;
}
}
}
cc_sweep(buffer, bufsize, tokens, length)
char *buffer;
struct cc **tokens;
register length;
{
register struct cc *p;
register char *cp;
register i;
short *hc;
short *places = cc_places[length];
struct cc **pp = tokens;
short threshold = thresh(length);
#ifndef cc_weight
short wthreshold = wthresh(length);
short limit = wlimit(length);
#endif
int time;
short pc = tt.tt_padc;
i = length - 1;
bufsize -= i;
cp = buffer + i;
hc = cc_hashcodes;
time = cc_time0;
for (i = 0; i < bufsize; i++, time++) {
struct cc **h;
{
register short *hc1 = hc;
register short c = *cp++;
register short hh;
if ((hh = *hc1) < 0 || c == pc) {
*hc1++ = -1;
hc = hc1;
continue;
}
h = cc_htab + (*hc1++ = hash(hh, c));
hc = hc1;
}
for (p = *h; p != 0; p = p->hforw)
if (p->length == (char) length) {
register char *p1 = p->string;
register char *p2 = cp - length;
register n = length;
do
if (*p1++ != *p2++)
goto fail;
while (--n);
break;
fail:;
}
if (p == 0) {
p = cc_q1a.qback;
if (p == &cc_q1a ||
p->time >= cc_time0 && p->length == (char) length)
continue;
if (p->hback != 0)
if ((*p->hback = p->hforw) != 0)
p->hforw->hback = p->hback;
{
register char *p1 = p->string;
register char *p2 = cp - length;
register n = length;
do
*p1++ = *p2++;
while (--n);
}
p->length = length;
#ifndef cc_weight
p->weight = cc_weight;
#endif
p->time = time;
p->bcount = 1;
p->ccount = 0;
p->flag = 0;
if ((p->hforw = *h) != 0)
p->hforw->hback = &p->hforw;
*h = p;
p->hback = h;
qinsert(p, &cc_q1a);
places[i] = -1;
p->places = i;
#ifdef STATS
ntoken_stat++;
#endif
} else if (p->time < cc_time0) {
#ifndef cc_weight
if ((p->weight += p->time - time) < 0)
p->weight = cc_weight;
else if ((p->weight += cc_weight) > limit)
p->weight = limit;
#endif
p->time = time;
p->bcount = 1;
p->ccount = 0;
if (p->code >= 0) {
p->flag = 1;
*pp++ = p;
} else
#ifndef cc_weight
if (p->weight >= wthreshold) {
p->flag = 1;
*pp++ = p;
qinsert(p, &cc_q1b);
} else
#endif
{
p->flag = 0;
qinsert(p, &cc_q1a);
}
places[i] = -1;
p->places = i;
#ifdef STATS
ntoken_stat++;
#endif
} else if (p->time + length > time) {
/*
* overlapping token, don't count as two and
* don't update time, but do adjust weight to offset
* the difference
*/
#ifndef cc_weight
if (cc_weight != 0) { /* XXX */
p->weight += time - p->time;
if (!p->flag && p->weight >= wthreshold) {
p->flag = 1;
*pp++ = p;
qinsert(p, &cc_q1b);
}
}
#endif
places[i] = p->places;
p->places = i;
} else {
#ifndef cc_weight
if ((p->weight += p->time - time) < 0)
p->weight = cc_weight;
else if ((p->weight += cc_weight) > limit)
p->weight = limit;
#endif
p->time = time;
p->bcount++;
if (!p->flag &&
/* code must be < 0 if flag false here */
(p->bcount >= threshold
#ifndef cc_weight
|| p->weight >= wthreshold
#endif
)) {
p->flag = 1;
*pp++ = p;
qinsert(p, &cc_q1b);
}
places[i] = p->places;
p->places = i;
}
}
if ((i = pp - tokens) > 0) {
*pp = 0;
if (cc_reverse)
cc_sweep_reverse(tokens, places);
if (cc_sort && i > 1) {
int cc_token_compare();
qsort((char *) tokens, i, sizeof *tokens,
cc_token_compare);
}
if (cc_chop) {
if ((i = i * cc_chop / 100) == 0)
i = 1;
tokens[i] = 0;
}
i++;
}
return i;
}
cc_sweep_reverse(pp, places)
register struct cc **pp;
register short *places;
{
register struct cc *p;
register short front, back, t;
while ((p = *pp++) != 0) {
back = -1;
t = p->places;
/* the list is never empty */
do {
front = places[t];
places[t] = back;
back = t;
} while ((t = front) >= 0);
p->places = back;
}
}
cc_compress_phase(output, bufsize, tokens, ntoken)
struct cc **output;
struct cc **tokens;
{
register i;
bzero((char *) output, bufsize * sizeof *output);
for (i = 0; i < cc_npass0; i++)
cc_compress_phase1(output, tokens, ntoken, 0);
for (i = 0; i < cc_npass1; i++)
cc_compress_phase1(output, tokens, ntoken, 1);
cc_compress_cleanup(output, bufsize);
}
cc_compress_phase1(output, tokens, ntoken, flag)
register struct cc **output;
struct cc **tokens;
{
register struct cc **pp;
#ifdef STATS
register int i = 0;
int nt = 0, cc = 0, nc = 0;
#endif
#ifdef STATS
if (verbose >= 0)
time_begin();
if (verbose > 0)
printf("Compress:");
#endif
pp = tokens;
while (pp < tokens + ntoken) {
#ifdef STATS
if (verbose > 0) {
ntoken_stat = 0;
ccount_stat = 0;
ncover_stat = 0;
if (i > 2) {
printf("\n ");
i = 0;
}
i++;
printf(" (%d", (*pp)->length);
(void) fflush(stdout);
}
#endif
pp += cc_compress(output, pp, flag);
#ifdef STATS
if (verbose > 0) {
printf(" %dt %du %dc)", ntoken_stat, ccount_stat,
ncover_stat);
nt += ntoken_stat;
cc += ccount_stat;
nc += ncover_stat;
}
#endif
}
#ifdef STATS
if (verbose > 0)
printf("\n total: (%dt %du %dc)\n", nt, cc, nc);
if (verbose >= 0)
time_end();
#endif
}
cc_compress_cleanup(output, bufsize)
register struct cc **output;
{
register struct cc **end;
/* the previous output phase may have been interrupted */
qinsertq(&cc_q0b, &cc_q0a);
for (end = output + bufsize; output < end;) {
register struct cc *p;
register length;
if ((p = *output) == 0) {
output++;
continue;
}
length = p->length;
if (!p->flag) {
} else if (p->code >= 0) {
qinsert(p, &cc_q0b);
p->flag = 0;
} else if (p->ccount == 0) {
*output = 0;
} else if (p->ccount >= thresh(length)
#ifndef cc_weight
|| wthreshp(p->weight, length)
#endif
) {
p->flag = 0;
} else {
p->ccount = 0;
*output = 0;
}
output += length;
}
}
cc_compress(output, tokens, flag)
struct cc **output;
struct cc **tokens;
char flag;
{
struct cc **pp = tokens;
register struct cc *p = *pp++;
int length = p->length;
int threshold = thresh(length);
#ifndef cc_weight
short wthreshold = wthresh(length);
#endif
short *places = cc_places[length];
int *initial_scores = cc_initial_scores[length];
int initial_score0 = put_token_score(length);
do {
int score;
register struct cc_undo *undop;
int ccount;
#ifdef STATS
int ncover;
#endif
int i;
ccount = p->ccount;
if ((short) ccount >= p->bcount)
continue;
if (p->code >= 0 || ccount >= threshold)
score = 0;
#ifndef cc_weight
else if (p->weight >= wthreshold)
/* allow one fewer match than normal */
/* XXX, should adjust for ccount */
score = - tt.tt_set_token_cost;
#endif
else
score = initial_scores[ccount];
undop = cc_undo;
#ifdef STATS
ncover = 0;
#endif
for (i = p->places; i >= 0; i = places[i]) {
register struct cc **jp;
register struct cc *x;
register struct cc **ip = output + i;
register score0 = initial_score0;
struct cc **iip = ip + length;
struct cc_undo *undop1 = undop;
if ((x = *(jp = ip)) != 0)
goto z;
while (--jp >= output)
if ((x = *jp) != 0) {
if (jp + x->length > ip)
goto z;
break;
}
jp = ip + 1;
while (jp < iip) {
if ((x = *jp) == 0) {
jp++;
continue;
}
z:
if (x == p)
goto undo;
#ifdef STATS
ncover++;
#endif
undop->pos = jp;
undop->val = x;
undop++;
*jp = 0;
x->ccount--;
score_adjust(score0, x);
if (score0 < 0 && flag)
goto undo;
jp += x->length;
}
undop->pos = ip;
undop->val = 0;
undop++;
*ip = p;
ccount++;
score += score0;
continue;
undo:
while (--undop >= undop1)
if (*undop->pos = x = undop->val)
x->ccount++;
undop++;
}
if (score > 0) {
#ifdef STATS
ccount_stat += ccount - p->ccount;
ntoken_stat++;
ncover_stat += ncover;
#endif
p->ccount = ccount;
} else {
register struct cc_undo *u = cc_undo;
while (--undop >= u) {
register struct cc *x;
if (*undop->pos = x = undop->val)
x->ccount++;
}
}
} while ((p = *pp++) != 0);
return pp - tokens;
}
cc_output_phase(buffer, output, bufsize)
register char *buffer;
register struct cc **output;
register bufsize;
{
register i;
register struct cc *p, *p1;
for (i = 0; i < bufsize;) {
if ((p = output[i]) == 0) {
ttputc(buffer[i]);
i++;
} else if (p->code >= 0) {
if (--p->ccount == 0)
qinsert(p, &cc_q0a);
(*tt.tt_put_token)(p->code, p->string, p->length);
wwntokuse++;
wwntoksave += put_token_score(p->length);
i += p->length;
} else if ((p1 = cc_q0a.qback) != &cc_q0a) {
p->code = p1->code;
p1->code = -1;
qinsert(p1, &cc_q1a);
if (--p->ccount == 0)
qinsert(p, &cc_q0a);
else
qinsert(p, &cc_q0b);
(*tt.tt_set_token)(p->code, p->string, p->length);
wwntokdef++;
wwntoksave -= tt.tt_set_token_cost;
i += p->length;
} else {
p->ccount--;
ttwrite(p->string, p->length);
wwntokbad++;
i += p->length;
}
}
wwntokc += bufsize;
}
cc_token_compare(p1, p2)
struct cc **p1, **p2;
{
return (*p2)->bcount - (*p1)->bcount;
}
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