usr.bin/window/compress.c

   1 /*      $NetBSD: compress.c,v 1.7 2009/04/14 08:50:06 lukem Exp $       */
   2
   3 /*
   4  * Copyright (c) 1989, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Edward Wang at The University of California, Berkeley.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 #if 0
  38 static char sccsid[] = "@(#)compress.c  8.1 (Berkeley) 6/6/93";
  39 #else
  40 __RCSID("$NetBSD: compress.c,v 1.7 2009/04/14 08:50:06 lukem Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 #include <fcntl.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include "defs.h"
  49 #include "tt.h"
  50
  51         /* special */
  52 int cc_trace = 0;
  53 FILE *cc_trace_fp;
  54
  55         /* tunable parameters */
  56
  57 int cc_reverse = 1;
  58 int cc_sort = 0;
  59 int cc_chop = 0;
  60
  61 int cc_token_max = 8;           /* <= TOKEN_MAX */
  62 int cc_token_min = 2;           /* > tt.tt_put_token_cost */
  63 int cc_npass0 = 1;
  64 int cc_npass1 = 1;
  65
  66 int cc_bufsize = 1024 * 3;      /* XXX, or 80 * 24 * 2 */
  67
  68 int cc_ntoken = 8192;
  69
  70 #define cc_weight XXX
  71 #ifndef cc_weight
  72 int cc_weight = 0;
  73 #endif
  74
  75 #define TOKEN_MAX 16
  76
  77 struct cc {
  78         char string[TOKEN_MAX];
  79         char length;
  80         char flag;
  81 #ifndef cc_weight
  82         short weight;
  83 #endif
  84         long time;              /* time last seen */
  85         short bcount;           /* count in this buffer */
  86         short ccount;           /* count in compression */
  87         short places;           /* places in the buffer */
  88         short code;             /* token code */
  89         struct cc *qforw, *qback;
  90         struct cc *hforw, **hback;
  91 };
  92
  93 short cc_thresholds[TOKEN_MAX + 1];
  94 #define thresh(length) (cc_thresholds[length])
  95 #define threshp(code, count, length) \
  96         ((code) >= 0 || (short) (count) >= cc_thresholds[length])
  97
  98 #ifndef cc_weight
  99 short cc_wthresholds[TOKEN_MAX + 1];
 100 #define wthresh(length) (cc_wthresholds[length])
 101 #define wthreshp(weight, length) ((short) (weight) >= cc_wthresholds[length])
 102 #else
 103 #define wthreshp(weight, length) (0)
 104 #endif
 105
 106 #ifndef cc_weight
 107 short cc_wlimits[TOKEN_MAX + 1];
 108 #define wlimit(length) (cc_wlimits[length])
 109 #endif
 110
 111 #define put_token_score(length) ((length) - tt.tt_put_token_cost)
 112
 113 int cc_score_adjustments[TOKEN_MAX + 1][8]; /* XXX, 8 > max of cc_thresholds */
 114 #define score_adjust(score, p) \
 115         do { \
 116                 int _length = (p)->length; \
 117                 int _ccount = (p)->ccount; \
 118                 if (threshp((p)->code, _ccount, _length) || \
 119                     wthreshp((p)->weight, _length)) /* XXX */ \
 120                         (score) -= _length - tt.tt_put_token_cost; \
 121                 else \
 122                         (score) += cc_score_adjustments[_length][_ccount]; \
 123         } while (0)
 124
 125 int cc_initial_scores[TOKEN_MAX + 1][8]; /* XXX, 8 > max of cc_thresholds */
 126
 127 struct cc cc_q0a, cc_q0b, cc_q1a, cc_q1b;
 128
 129 #define qinsert(p1, p2) \
 130         do { \
 131                 struct cc *forw = (p1)->qforw; \
 132                 struct cc *back = (p1)->qback; \
 133                 back->qforw = forw; \
 134                 forw->qback = back; \
 135                 forw = (p2)->qforw; \
 136                 (p1)->qforw = forw; \
 137                 forw->qback = (p1); \
 138                 (p2)->qforw = (p1); \
 139                 (p1)->qback = (p2); \
 140         } while (0)
 141
 142 #define qinsertq(q, p) \
 143         ((q)->qforw == (q) ? 0 : \
 144          ((q)->qback->qforw = (p)->qforw, \
 145           (p)->qforw->qback = (q)->qback, \
 146           (q)->qforw->qback = (p), \
 147           (p)->qforw = (q)->qforw, \
 148           (q)->qforw = (q), \
 149           (q)->qback = (q)))
 150
 151 #define H               (14)
 152 #define HSIZE           (1 << H)
 153 #define hash(h, c)      (((((h) >> (H - 8)) | (h) << 8) ^ (c)) & (HSIZE - 1))
 154
 155 char *cc_buffer;
 156 struct cc **cc_output;                  /* the output array */
 157 short *cc_places[TOKEN_MAX + 1];
 158 short *cc_hashcodes;                    /* for computing hashcodes */
 159 struct cc **cc_htab;                    /* the hash table */
 160 struct cc **cc_tokens;                  /* holds all the active tokens */
 161 struct cc_undo {
 162         struct cc **pos;
 163         struct cc *val;
 164 } *cc_undo;
 165
 166 long cc_time, cc_time0;
 167
 168 char *cc_tt_ob, *cc_tt_obe;
 169
 170 int     cc_compress(struct cc **, struct cc **, char);
 171 void    cc_compress_cleanup(struct cc **, int);
 172 void    cc_compress_phase(struct cc **, int, struct cc **, int);
 173 void    cc_compress_phase1(struct cc **, struct cc **, int, int);
 174 void    cc_output_phase(char *, struct cc **, int);
 175 int     cc_sweep(char *, int, struct cc **, int);
 176 void    cc_sweep0(char *, int, int);
 177 int     cc_sweep_phase(char *, int, struct cc **);
 178 void    cc_sweep_reverse(struct cc **, short *);
 179 int     cc_token_compare(const void *, const void *);
 180
 181 int
 182 ccinit(void)
 183 {
 184         int i, j;
 185         struct cc *p;
 186
 187         if (tt.tt_token_max > cc_token_max)
 188                 tt.tt_token_max = cc_token_max;
 189         if (tt.tt_token_min < cc_token_min)
 190                 tt.tt_token_min = cc_token_min;
 191         if (tt.tt_token_min > tt.tt_token_max) {
 192                 tt.tt_ntoken = 0;
 193                 return 0;
 194         }
 195         if (tt.tt_ntoken > cc_ntoken / 2)       /* not likely */
 196                 tt.tt_ntoken = cc_ntoken / 2;
 197 #define C(x) (sizeof (x) / sizeof *(x))
 198         for (i = 0; i < (int)C(cc_thresholds); i++) {
 199                 int h = i - tt.tt_put_token_cost;
 200                 if (h > 0)
 201                         cc_thresholds[i] =
 202                                 (tt.tt_set_token_cost + 1 + h - 1) / h + 1;
 203                 else
 204                         cc_thresholds[i] = 0;
 205         }
 206         for (i = 0; i < (int)C(cc_score_adjustments); i++) {
 207                 int t = cc_thresholds[i];
 208                 for (j = 0; j < (int)C(*cc_score_adjustments); j++) {
 209                         if (j >= t)
 210                                 cc_score_adjustments[i][j] =
 211                                         - (i - tt.tt_put_token_cost);
 212                         else if (j < t - 1)
 213                                 cc_score_adjustments[i][j] = 0;
 214                         else
 215                                 /*
 216                                  * cost now is
 217                                  *      length * (ccount + 1)           a
 218                                  * cost before was
 219                                  *      set-token-cost + length +
 220                                  *              ccount * put-token-cost b
 221                                  * the score adjustment is (b - a)
 222                                  */
 223                                 cc_score_adjustments[i][j] =
 224                                         tt.tt_set_token_cost + i +
 225                                                 j * tt.tt_put_token_cost -
 226                                                         i * (j + 1);
 227                         if (j >= t)
 228                                 cc_initial_scores[i][j] = 0;
 229                         else
 230                                 /*
 231                                  * - (set-token-cost +
 232                                  *      (length - put-token-cost) -
 233                                  *      (length - put-token-cost) * ccount)
 234                                  */
 235                                 cc_initial_scores[i][j] =
 236                                         - (tt.tt_set_token_cost +
 237                                            (i - tt.tt_put_token_cost) -
 238                                            (i - tt.tt_put_token_cost) * j);
 239                 }
 240         }
 241 #ifndef cc_weight
 242         for (i = 1; i < C(cc_wthresholds); i++) {
 243                 cc_wthresholds[i] =
 244                         ((tt.tt_set_token_cost + tt.tt_put_token_cost) / i +
 245                                 i / 5 + 1) *
 246                                 cc_weight + 1;
 247                 cc_wlimits[i] = cc_wthresholds[i] + cc_weight;
 248         }
 249 #endif
 250 #undef C
 251         if ((cc_output = (struct cc **)
 252              malloc((unsigned) cc_bufsize * sizeof *cc_output)) == 0)
 253                 goto nomem;
 254         if ((cc_hashcodes = (short *)
 255              malloc((unsigned) cc_bufsize * sizeof *cc_hashcodes)) == 0)
 256                 goto nomem;
 257         if ((cc_htab = (struct cc **) malloc(HSIZE * sizeof *cc_htab)) == 0)
 258                 goto nomem;
 259         if ((cc_tokens = (struct cc **)
 260              malloc((unsigned)
 261                     (cc_ntoken + tt.tt_token_max - tt.tt_token_min + 1) *
 262                     sizeof *cc_tokens)) == 0)
 263                 goto nomem;
 264         if ((cc_undo = (struct cc_undo *)
 265              malloc((unsigned) cc_bufsize * sizeof *cc_undo)) == 0)
 266                 goto nomem;
 267         for (i = tt.tt_token_min; i <= tt.tt_token_max; i++)
 268                 if ((cc_places[i] = (short *)
 269                      malloc((unsigned) cc_bufsize * sizeof **cc_places)) == 0)
 270                         goto nomem;
 271         cc_q0a.qforw = cc_q0a.qback = &cc_q0a;
 272         cc_q0b.qforw = cc_q0b.qback = &cc_q0b;
 273         cc_q1a.qforw = cc_q1a.qback = &cc_q1a;
 274         cc_q1b.qforw = cc_q1b.qback = &cc_q1b;
 275         if ((p = (struct cc *) malloc((unsigned) cc_ntoken * sizeof *p)) == 0)
 276                 goto nomem;
 277         for (i = 0; i < tt.tt_ntoken; i++) {
 278                 p->code = i;
 279                 p->time = -1;
 280                 p->qback = cc_q0a.qback;
 281                 p->qforw = &cc_q0a;
 282                 p->qback->qforw = p;
 283                 cc_q0a.qback = p;
 284                 p++;
 285         }
 286         for (; i < cc_ntoken; i++) {
 287                 p->code = -1;
 288                 p->time = -1;
 289                 p->qback = cc_q1a.qback;
 290                 p->qforw = &cc_q1a;
 291                 p->qback->qforw = p;
 292                 cc_q1a.qback = p;
 293                 p++;
 294         }
 295         cc_tt_ob = tt_ob;
 296         cc_tt_obe = tt_obe;
 297         if ((cc_buffer = malloc((unsigned) cc_bufsize)) == 0)
 298                 goto nomem;
 299         return 0;
 300 nomem:
 301         wwerrno = WWE_NOMEM;
 302         return -1;
 303 }
 304
 305 void
 306 ccstart(void)
 307 {
 308         ttflush();
 309         tt_obp = tt_ob = cc_buffer;
 310         tt_obe = tt_ob + cc_bufsize;
 311         tt.tt_flush = ccflush;
 312         if (cc_trace) {
 313                 cc_trace_fp = fopen("window-trace", "a");
 314                 (void) fcntl(fileno(cc_trace_fp), F_SETFD, 1);
 315         }
 316         ccreset();
 317 }
 318
 319 void
 320 ccreset(void)
 321 {
 322         struct cc *p;
 323
 324         memset((char *) cc_htab, 0, HSIZE * sizeof *cc_htab);
 325         for (p = cc_q0a.qforw; p != &cc_q0a; p = p->qforw)
 326                 p->hback = 0;
 327         for (p = cc_q1a.qforw; p != &cc_q1a; p = p->qforw)
 328                 p->hback = 0;
 329 }
 330
 331 void
 332 ccend(void)
 333 {
 334
 335         ttflush();
 336         tt_obp = tt_ob = cc_tt_ob;
 337         tt_obe = cc_tt_obe;
 338         tt.tt_flush = 0;
 339         if (cc_trace_fp != NULL) {
 340                 (void) fclose(cc_trace_fp);
 341                 cc_trace_fp = NULL;
 342         }
 343 }
 344
 345 void
 346 ccflush(void)
 347 {
 348         int bufsize = tt_obp - tt_ob;
 349         int n;
 350
 351         if (tt_ob != cc_buffer)
 352                 abort();
 353         if (cc_trace_fp != NULL) {
 354                 (void) fwrite(tt_ob, 1, bufsize, cc_trace_fp);
 355                 (void) putc(-1, cc_trace_fp);
 356         }
 357         tt.tt_flush = 0;
 358         (*tt.tt_compress)(1);
 359         if (bufsize < tt.tt_token_min) {
 360                 ttflush();
 361                 goto out;
 362         }
 363         tt_obp = tt_ob = cc_tt_ob;
 364         tt_obe = cc_tt_obe;
 365         cc_time0 = cc_time;
 366         cc_time += bufsize;
 367         n = cc_sweep_phase(cc_buffer, bufsize, cc_tokens);
 368         cc_compress_phase(cc_output, bufsize, cc_tokens, n);
 369         cc_output_phase(cc_buffer, cc_output, bufsize);
 370         ttflush();
 371         tt_obp = tt_ob = cc_buffer;
 372         tt_obe = cc_buffer + cc_bufsize;
 373 out:
 374         (*tt.tt_compress)(0);
 375         tt.tt_flush = ccflush;
 376 }
 377
 378 int
 379 cc_sweep_phase(char *buffer, int bufsize, struct cc **tokens)
 380 {
 381         struct cc **pp = tokens;
 382         int i, n;
 383 #ifdef STATS
 384         int nn, ii;
 385 #endif
 386
 387 #ifdef STATS
 388         if (verbose >= 0)
 389                 time_begin();
 390         if (verbose > 0)
 391                 printf("Sweep:");
 392 #endif
 393         cc_sweep0(buffer, bufsize, tt.tt_token_min - 1);
 394 #ifdef STATS
 395         ntoken_stat = 0;
 396         nn = 0;
 397         ii = 0;
 398 #endif
 399         for (i = tt.tt_token_min; i <= tt.tt_token_max; i++) {
 400 #ifdef STATS
 401                 if (verbose > 0) {
 402                         if (ii > 7) {
 403                                 printf("\n      ");
 404                                 ii = 0;
 405                         }
 406                         ii++;
 407                         printf(" (%d", i);
 408                         (void) fflush(stdout);
 409                 }
 410 #endif
 411                 n = cc_sweep(buffer, bufsize, pp, i);
 412                 pp += n;
 413 #ifdef STATS
 414                 if (verbose > 0) {
 415                         if (--n > 0) {
 416                                 printf(" %d", n);
 417                                 nn += n;
 418                         }
 419                         putchar(')');
 420                 }
 421 #endif
 422         }
 423         qinsertq(&cc_q1b, &cc_q1a);
 424 #ifdef STATS
 425         if (verbose > 0)
 426                 printf("\n       %d tokens, %d candidates\n",
 427                         ntoken_stat, nn);
 428         if (verbose >= 0)
 429                 time_end();
 430 #endif
 431         return pp - tokens;
 432 }
 433
 434 void
 435 cc_sweep0(char *buffer, int n, int length)
 436 {
 437         char *p;
 438         short *hc;
 439         int i;
 440         short c;
 441         short pc = tt.tt_padc;
 442
 443         /* n and length are at least 1 */
 444         p = buffer++;
 445         hc = cc_hashcodes;
 446         i = n;
 447         do {
 448                 if ((*hc++ = *p++) == pc)
 449                         hc[-1] = -1;
 450         } while (--i);
 451         while (--length) {
 452                 p = buffer++;
 453                 hc = cc_hashcodes;
 454                 for (i = n--; --i;) {
 455                         if ((c = *p++) == pc || *hc < 0)
 456                                 c = -1;
 457                         else
 458                                 c = hash(*hc, c);
 459                         *hc++ = c;
 460                 }
 461         }
 462 }
 463
 464 int
 465 cc_sweep(char *buffer, int bufsize, struct cc **tokens, int length)
 466 {
 467         struct cc *p;
 468         char *cp;
 469         int i;
 470         short *hc;
 471         short *places = cc_places[length];
 472         struct cc **pp = tokens;
 473         short threshold = thresh(length);
 474 #ifndef cc_weight
 475         short wthreshold = wthresh(length);
 476         short limit = wlimit(length);
 477 #endif
 478         int time0;
 479         short pc = tt.tt_padc;
 480
 481         i = length - 1;
 482         bufsize -= i;
 483         cp = buffer + i;
 484         hc = cc_hashcodes;
 485         time0 = cc_time0;
 486         for (i = 0; i < bufsize; i++, time0++) {
 487                 struct cc **h;
 488
 489                 {
 490                         short *hc1 = hc;
 491                         short c = *cp++;
 492                         short hh;
 493                         if ((hh = *hc1) < 0 || c == pc) {
 494                                 *hc1++ = -1;
 495                                 hc = hc1;
 496                                 continue;
 497                         }
 498                         h = cc_htab + (*hc1++ = hash(hh, c));
 499                         hc = hc1;
 500                 }
 501                 for (p = *h; p != 0; p = p->hforw)
 502                         if (p->length == (char) length) {
 503                                 char *p1 = p->string;
 504                                 char *p2 = cp - length;
 505                                 int n = length;
 506                                 do
 507                                         if (*p1++ != *p2++)
 508                                                 goto fail;
 509                                 while (--n);
 510                                 break;
 511                         fail:;
 512                         }
 513                 if (p == 0) {
 514                         p = cc_q1a.qback;
 515                         if (p == &cc_q1a ||
 516                             (p->time >= cc_time0 && p->length == (char) length))
 517                                 continue;
 518                         if (p->hback != 0)
 519                                 if ((*p->hback = p->hforw) != 0)
 520                                         p->hforw->hback = p->hback;
 521                         {
 522                                 char *p1 = p->string;
 523                                 char *p2 = cp - length;
 524                                 int n = length;
 525                                 do
 526                                         *p1++ = *p2++;
 527                                 while (--n);
 528                         }
 529                         p->length = length;
 530 #ifndef cc_weight
 531                         p->weight = cc_weight;
 532 #endif
 533                         p->time = time0;
 534                         p->bcount = 1;
 535                         p->ccount = 0;
 536                         p->flag = 0;
 537                         if ((p->hforw = *h) != 0)
 538                                 p->hforw->hback = &p->hforw;
 539                         *h = p;
 540                         p->hback = h;
 541                         qinsert(p, &cc_q1a);
 542                         places[i] = -1;
 543                         p->places = i;
 544 #ifdef STATS
 545                         ntoken_stat++;
 546 #endif
 547                 } else if (p->time < cc_time0) {
 548 #ifndef cc_weight
 549                         if ((p->weight += p->time - time0) < 0)
 550                                 p->weight = cc_weight;
 551                         else if ((p->weight += cc_weight) > limit)
 552                                 p->weight = limit;
 553 #endif
 554                         p->time = time0;
 555                         p->bcount = 1;
 556                         p->ccount = 0;
 557                         if (p->code >= 0) {
 558                                 p->flag = 1;
 559                                 *pp++ = p;
 560                         } else
 561 #ifndef cc_weight
 562                         if (p->weight >= wthreshold) {
 563                                 p->flag = 1;
 564                                 *pp++ = p;
 565                                 qinsert(p, &cc_q1b);
 566                         } else
 567 #endif
 568                         {
 569                                 p->flag = 0;
 570                                 qinsert(p, &cc_q1a);
 571                         }
 572                         places[i] = -1;
 573                         p->places = i;
 574 #ifdef STATS
 575                         ntoken_stat++;
 576 #endif
 577                 } else if (p->time + length > time0) {
 578                         /*
 579                          * overlapping token, don't count as two and
 580                          * don't update time0, but do adjust weight to offset
 581                          * the difference
 582                          */
 583 #ifndef cc_weight
 584                         if (cc_weight != 0) {   /* XXX */
 585                                 p->weight += time0 - p->time;
 586                                 if (!p->flag && p->weight >= wthreshold) {
 587                                         p->flag = 1;
 588                                         *pp++ = p;
 589                                         qinsert(p, &cc_q1b);
 590                                 }
 591                         }
 592 #endif
 593                         places[i] = p->places;
 594                         p->places = i;
 595                 } else {
 596 #ifndef cc_weight
 597                         if ((p->weight += p->time - time0) < 0)
 598                                 p->weight = cc_weight;
 599                         else if ((p->weight += cc_weight) > limit)
 600                                 p->weight = limit;
 601 #endif
 602                         p->time = time0;
 603                         p->bcount++;
 604                         if (!p->flag &&
 605                             /* code must be < 0 if flag false here */
 606                             (p->bcount >= threshold
 607 #ifndef cc_weight
 608                              || p->weight >= wthreshold
 609 #endif
 610                              )) {
 611                                 p->flag = 1;
 612                                 *pp++ = p;
 613                                 qinsert(p, &cc_q1b);
 614                         }
 615                         places[i] = p->places;
 616                         p->places = i;
 617                 }
 618         }
 619         if ((i = pp - tokens) > 0) {
 620                 *pp = 0;
 621                 if (cc_reverse)
 622                         cc_sweep_reverse(tokens, places);
 623                 if (cc_sort && i > 1) {
 624                         qsort((char *) tokens, i, sizeof *tokens,
 625                               cc_token_compare);
 626                 }
 627                 if (cc_chop) {
 628                         if ((i = i * cc_chop / 100) == 0)
 629                                 i = 1;
 630                         tokens[i] = 0;
 631                 }
 632                 i++;
 633         }
 634         return i;
 635 }
 636
 637 void
 638 cc_sweep_reverse(struct cc **pp, short int *places)
 639 {
 640         struct cc *p;
 641         short frnt, back, t;
 642
 643         while ((p = *pp++) != 0) {
 644                 back = -1;
 645                 t = p->places;
 646                 /* the list is never empty */
 647                 do {
 648                         frnt = places[t];
 649                         places[t] = back;
 650                         back = t;
 651                 } while ((t = frnt) >= 0);
 652                 p->places = back;
 653         }
 654 }
 655
 656 void
 657 cc_compress_phase(struct cc **output, int bufsize, struct cc **tokens, int ntoken)
 658 {
 659         int i;
 660
 661         memset((char *) output, 0, bufsize * sizeof *output);
 662         for (i = 0; i < cc_npass0; i++)
 663                 cc_compress_phase1(output, tokens, ntoken, 0);
 664         for (i = 0; i < cc_npass1; i++)
 665                 cc_compress_phase1(output, tokens, ntoken, 1);
 666         cc_compress_cleanup(output, bufsize);
 667 }
 668
 669 void
 670 cc_compress_phase1(struct cc **output, struct cc **tokens, int ntoken, int flag)
 671 {
 672         struct cc **pp;
 673 #ifdef STATS
 674         int i = 0;
 675         int nt = 0, cc = 0, nc = 0;
 676 #endif
 677
 678 #ifdef STATS
 679         if (verbose >= 0)
 680                 time_begin();
 681         if (verbose > 0)
 682                 printf("Compress:");
 683 #endif
 684         pp = tokens;
 685         while (pp < tokens + ntoken) {
 686 #ifdef STATS
 687                 if (verbose > 0) {
 688                         ntoken_stat = 0;
 689                         ccount_stat = 0;
 690                         ncover_stat = 0;
 691                         if (i > 2) {
 692                                 printf("\n         ");
 693                                 i = 0;
 694                         }
 695                         i++;
 696                         printf(" (%d", (*pp)->length);
 697                         (void) fflush(stdout);
 698                 }
 699 #endif
 700                 pp += cc_compress(output, pp, flag);
 701 #ifdef STATS
 702                 if (verbose > 0) {
 703                         printf(" %dt %du %dc)", ntoken_stat, ccount_stat,
 704                                ncover_stat);
 705                         nt += ntoken_stat;
 706                         cc += ccount_stat;
 707                         nc += ncover_stat;
 708                 }
 709 #endif
 710         }
 711 #ifdef STATS
 712         if (verbose > 0)
 713                 printf("\n   total: (%dt %du %dc)\n", nt, cc, nc);
 714         if (verbose >= 0)
 715                 time_end();
 716 #endif
 717 }
 718
 719 void
 720 cc_compress_cleanup(struct cc **output, int bufsize)
 721 {
 722         struct cc **end;
 723
 724         /* the previous output phase may have been interrupted */
 725         qinsertq(&cc_q0b, &cc_q0a);
 726         for (end = output + bufsize; output < end;) {
 727                 struct cc *p;
 728                 int length;
 729                 if ((p = *output) == 0) {
 730                         output++;
 731                         continue;
 732                 }
 733                 length = p->length;
 734                 if (!p->flag) {
 735                 } else if (p->code >= 0) {
 736                         qinsert(p, &cc_q0b);
 737                         p->flag = 0;
 738                 } else if (p->ccount == 0) {
 739                         *output = 0;
 740                 } else if (p->ccount >= thresh(length)
 741 #ifndef cc_weight
 742                            || wthreshp(p->weight, length)
 743 #endif
 744                            ) {
 745                         p->flag = 0;
 746                 } else {
 747                         p->ccount = 0;
 748                         *output = 0;
 749                 }
 750                 output += length;
 751         }
 752 }
 753
 754 int
 755 cc_compress(struct cc **output, struct cc **tokens, char flag)
 756 {
 757         struct cc **pp = tokens;
 758         struct cc *p = *pp++;
 759         int length = p->length;
 760         int threshold = thresh(length);
 761 #ifndef cc_weight
 762         short wthreshold = wthresh(length);
 763 #endif
 764         short *places = cc_places[length];
 765         int *initial_scores = cc_initial_scores[length];
 766         int initial_score0 = put_token_score(length);
 767
 768         do {
 769                 int score;
 770                 struct cc_undo *undop;
 771                 int ccount;
 772 #ifdef STATS
 773                 int ncover;
 774 #endif
 775                 int i;
 776
 777                 ccount = p->ccount;
 778                 if ((short) ccount >= p->bcount)
 779                         continue;
 780                 if (p->code >= 0 || ccount >= threshold)
 781                         score = 0;
 782 #ifndef cc_weight
 783                 else if (p->weight >= wthreshold)
 784                         /* allow one fewer match than normal */
 785                         /* XXX, should adjust for ccount */
 786                         score = - tt.tt_set_token_cost;
 787 #endif
 788                 else
 789                         score = initial_scores[ccount];
 790                 undop = cc_undo;
 791 #ifdef STATS
 792                 ncover = 0;
 793 #endif
 794                 for (i = p->places; i >= 0; i = places[i]) {
 795                         struct cc **jp;
 796                         struct cc *x;
 797                         struct cc **ip = output + i;
 798                         int score0 = initial_score0;
 799                         struct cc **iip = ip + length;
 800                         struct cc_undo *undop1 = undop;
 801
 802                         if ((x = *(jp = ip)) != 0)
 803                                 goto z;
 804                         while (--jp >= output)
 805                                 if ((x = *jp) != 0) {
 806                                         if (jp + x->length > ip)
 807                                                 goto z;
 808                                         break;
 809                                 }
 810                         jp = ip + 1;
 811                         while (jp < iip) {
 812                                 if ((x = *jp) == 0) {
 813                                         jp++;
 814                                         continue;
 815                                 }
 816                         z:
 817                                 if (x == p)
 818                                         goto undo;
 819 #ifdef STATS
 820                                 ncover++;
 821 #endif
 822                                 undop->pos = jp;
 823                                 undop->val = x;
 824                                 undop++;
 825                                 *jp = 0;
 826                                 x->ccount--;
 827                                 score_adjust(score0, x);
 828                                 if (score0 < 0 && flag)
 829                                         goto undo;
 830                                 jp += x->length;
 831                         }
 832                         undop->pos = ip;
 833                         undop->val = 0;
 834                         undop++;
 835                         *ip = p;
 836                         ccount++;
 837                         score += score0;
 838                         continue;
 839                 undo:
 840                         while (--undop >= undop1)
 841                                 if ((*undop->pos = x = undop->val))
 842                                         x->ccount++;
 843                         undop++;
 844                 }
 845                 if (score > 0) {
 846 #ifdef STATS
 847                         ccount_stat += ccount - p->ccount;
 848                         ntoken_stat++;
 849                         ncover_stat += ncover;
 850 #endif
 851                         p->ccount = ccount;
 852                 } else {
 853                         struct cc_undo *u = cc_undo;
 854                         while (--undop >= u) {
 855                                 struct cc *x;
 856                                 if ((*undop->pos = x = undop->val))
 857                                         x->ccount++;
 858                         }
 859                 }
 860         } while ((p = *pp++) != 0);
 861         return pp - tokens;
 862 }
 863
 864 void
 865 cc_output_phase(char *buffer, struct cc **output, int bufsize)
 866 {
 867         int i;
 868         struct cc *p, *p1;
 869
 870         for (i = 0; i < bufsize;) {
 871                 if ((p = output[i]) == 0) {
 872                         ttputc(buffer[i]);
 873                         i++;
 874                 } else if (p->code >= 0) {
 875                         if (--p->ccount == 0)
 876                                 qinsert(p, &cc_q0a);
 877                         (*tt.tt_put_token)(p->code, p->string, p->length);
 878                         wwntokuse++;
 879                         wwntoksave += put_token_score(p->length);
 880                         i += p->length;
 881                 } else if ((p1 = cc_q0a.qback) != &cc_q0a) {
 882                         p->code = p1->code;
 883                         p1->code = -1;
 884                         qinsert(p1, &cc_q1a);
 885                         if (--p->ccount == 0)
 886                                 qinsert(p, &cc_q0a);
 887                         else
 888                                 qinsert(p, &cc_q0b);
 889                         (*tt.tt_set_token)(p->code, p->string, p->length);
 890                         wwntokdef++;
 891                         wwntoksave -= tt.tt_set_token_cost;
 892                         i += p->length;
 893                 } else {
 894                         p->ccount--;
 895                         ttwrite(p->string, p->length);
 896                         wwntokbad++;
 897                         i += p->length;
 898                 }
 899         }
 900         wwntokc += bufsize;
 901 }
 902
 903 int
 904 cc_token_compare(const void *p1, const void *p2)
 905 {
 906         const struct cc * const * vp1 = p1;
 907         const struct cc * const * vp2 = p2;
 908         return (*vp2)->bcount - (*vp1)->bcount;
 909 }