1
2 /*-------------------------------------------------------------*/
3 /*--- Block sorting machinery ---*/
4 /*--- blocksort.c ---*/
5 /*-------------------------------------------------------------*/
6
7 /*--
8 This file is a part of bzip2 and/or libbzip2, a program and
9 library for lossless, block-sorting data compression.
10
11 Copyright (C) 1996-2002 Julian R Seward. All rights reserved.
12
13 Redistribution and use in source and binary forms, with or without
14 modification, are permitted provided that the following conditions
15 are met:
16
17 1. Redistributions of source code must retain the above copyright
18 notice, this list of conditions and the following disclaimer.
19
20 2. The origin of this software must not be misrepresented; you must
21 not claim that you wrote the original software. If you use this
22 software in a product, an acknowledgment in the product
23 documentation would be appreciated but is not required.
24
25 3. Altered source versions must be plainly marked as such, and must
26 not be misrepresented as being the original software.
27
28 4. The name of the author may not be used to endorse or promote
29 products derived from this software without specific prior written
30 permission.
31
32 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
33 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
34 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
36 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
38 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
39 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
40 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
41 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
42 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43
44 Julian Seward, Cambridge, UK.
45 jseward@acm.org
46 bzip2/libbzip2 version 1.0.6 of 6 September 2010
47 Copyright (C) 1996-2010 Julian Seward <jseward@bzip.org>
48
49 This program is based on (at least) the work of:
50 Mike Burrows
51 David Wheeler
52 Peter Fenwick
53 Alistair Moffat
54 Radford Neal
55 Ian H. Witten
56 Robert Sedgewick
57 Jon L. Bentley
58
59 For more information on these sources, see the manual.
60 --*/
61
62 #include "bzlib_private.h"
63
64 /*---------------------------------------------*/
65 /*--- Fallback O(N log(N)^2) sorting ---*/
66 /*--- algorithm, for repetitive blocks ---*/
67 /*---------------------------------------------*/
68
69 /*---------------------------------------------*/
70 static
71 __inline__
fallbackSimpleSort(UInt32 * fmap,UInt32 * eclass,Int32 lo,Int32 hi)72 void fallbackSimpleSort ( UInt32* fmap,
73 UInt32* eclass,
74 Int32 lo,
75 Int32 hi )
76 {
77 Int32 i, j, tmp;
78 UInt32 ec_tmp;
79
80 if (lo == hi) return;
81
82 if (hi - lo > 3) {
83 for ( i = hi-4; i >= lo; i-- ) {
84 tmp = fmap[i];
85 ec_tmp = eclass[tmp];
86 for ( j = i+4; j <= hi && ec_tmp > eclass[fmap[j]]; j += 4 )
87 fmap[j-4] = fmap[j];
88 fmap[j-4] = tmp;
89 }
90 }
91
92 for ( i = hi-1; i >= lo; i-- ) {
93 tmp = fmap[i];
94 ec_tmp = eclass[tmp];
95 for ( j = i+1; j <= hi && ec_tmp > eclass[fmap[j]]; j++ )
96 fmap[j-1] = fmap[j];
97 fmap[j-1] = tmp;
98 }
99 }
100
101
102 /*---------------------------------------------*/
103 #define fswap(zz1, zz2) \
104 { Int32 zztmp = zz1; zz1 = zz2; zz2 = zztmp; }
105
106 #define fvswap(zzp1, zzp2, zzn) \
107 { \
108 Int32 yyp1 = (zzp1); \
109 Int32 yyp2 = (zzp2); \
110 Int32 yyn = (zzn); \
111 while (yyn > 0) { \
112 fswap(fmap[yyp1], fmap[yyp2]); \
113 yyp1++; yyp2++; yyn--; \
114 } \
115 }
116
117
118 #define fmin(a,b) ((a) < (b)) ? (a) : (b)
119
120 #define fpush(lz,hz) { stackLo[sp] = lz; \
121 stackHi[sp] = hz; \
122 sp++; }
123
124 #define fpop(lz,hz) { sp--; \
125 lz = stackLo[sp]; \
126 hz = stackHi[sp]; }
127
128 #define FALLBACK_QSORT_SMALL_THRESH 10
129 #define FALLBACK_QSORT_STACK_SIZE 100
130
131
132 static
fallbackQSort3(UInt32 * fmap,UInt32 * eclass,Int32 loSt,Int32 hiSt)133 void fallbackQSort3 ( UInt32* fmap,
134 UInt32* eclass,
135 Int32 loSt,
136 Int32 hiSt )
137 {
138 Int32 unLo, unHi, ltLo, gtHi, n, m;
139 Int32 sp, lo, hi;
140 UInt32 med, r, r3;
141 Int32 stackLo[FALLBACK_QSORT_STACK_SIZE];
142 Int32 stackHi[FALLBACK_QSORT_STACK_SIZE];
143
144 r = 0;
145
146 sp = 0;
147 fpush ( loSt, hiSt );
148
149 while (sp > 0) {
150
151 AssertH ( sp < FALLBACK_QSORT_STACK_SIZE - 1, 1004 );
152
153 fpop ( lo, hi );
154 if (hi - lo < FALLBACK_QSORT_SMALL_THRESH) {
155 fallbackSimpleSort ( fmap, eclass, lo, hi );
156 continue;
157 }
158
159 /* Random partitioning. Median of 3 sometimes fails to
160 avoid bad cases. Median of 9 seems to help but
161 looks rather expensive. This too seems to work but
162 is cheaper. Guidance for the magic constants
163 7621 and 32768 is taken from Sedgewick's algorithms
164 book, chapter 35.
165 */
166 r = ((r * 7621) + 1) % 32768;
167 r3 = r % 3;
168 if (r3 == 0) med = eclass[fmap[lo]]; else
169 if (r3 == 1) med = eclass[fmap[(lo+hi)>>1]]; else
170 med = eclass[fmap[hi]];
171
172 unLo = ltLo = lo;
173 unHi = gtHi = hi;
174
175 while (1) {
176 while (1) {
177 if (unLo > unHi) break;
178 n = (Int32)eclass[fmap[unLo]] - (Int32)med;
179 if (n == 0) {
180 fswap(fmap[unLo], fmap[ltLo]);
181 ltLo++; unLo++;
182 continue;
183 };
184 if (n > 0) break;
185 unLo++;
186 }
187 while (1) {
188 if (unLo > unHi) break;
189 n = (Int32)eclass[fmap[unHi]] - (Int32)med;
190 if (n == 0) {
191 fswap(fmap[unHi], fmap[gtHi]);
192 gtHi--; unHi--;
193 continue;
194 };
195 if (n < 0) break;
196 unHi--;
197 }
198 if (unLo > unHi) break;
199 fswap(fmap[unLo], fmap[unHi]); unLo++; unHi--;
200 }
201
202 AssertD ( unHi == unLo-1, "fallbackQSort3(2)" );
203
204 if (gtHi < ltLo) continue;
205
206 n = fmin(ltLo-lo, unLo-ltLo); fvswap(lo, unLo-n, n);
207 m = fmin(hi-gtHi, gtHi-unHi); fvswap(unLo, hi-m+1, m);
208
209 n = lo + unLo - ltLo - 1;
210 m = hi - (gtHi - unHi) + 1;
211
212 if (n - lo > hi - m) {
213 fpush ( lo, n );
214 fpush ( m, hi );
215 } else {
216 fpush ( m, hi );
217 fpush ( lo, n );
218 }
219 }
220 }
221
222 #undef fmin
223 #undef fpush
224 #undef fpop
225 #undef fswap
226 #undef fvswap
227 #undef FALLBACK_QSORT_SMALL_THRESH
228 #undef FALLBACK_QSORT_STACK_SIZE
229
230
231 /*---------------------------------------------*/
232 /* Pre:
233 nblock > 0
234 eclass exists for [0 .. nblock-1]
235 ((UChar*)eclass) [0 .. nblock-1] holds block
236 ptr exists for [0 .. nblock-1]
237
238 Post:
239 ((UChar*)eclass) [0 .. nblock-1] holds block
240 All other areas of eclass destroyed
241 fmap [0 .. nblock-1] holds sorted order
242 bhtab [ 0 .. 2+(nblock/32) ] destroyed
243 */
244
245 #define SET_BH(zz) bhtab[(zz) >> 5] |= (1 << ((zz) & 31))
246 #define CLEAR_BH(zz) bhtab[(zz) >> 5] &= ~(1 << ((zz) & 31))
247 #define ISSET_BH(zz) (bhtab[(zz) >> 5] & (1 << ((zz) & 31)))
248 #define WORD_BH(zz) bhtab[(zz) >> 5]
249 #define UNALIGNED_BH(zz) ((zz) & 0x01f)
250
251 static
fallbackSort(UInt32 * fmap,UInt32 * eclass,UInt32 * bhtab,Int32 nblock,Int32 verb)252 void fallbackSort ( UInt32* fmap,
253 UInt32* eclass,
254 UInt32* bhtab,
255 Int32 nblock,
256 Int32 verb )
257 {
258 Int32 ftab[257];
259 Int32 ftabCopy[256];
260 Int32 H, i, j, k, l, r, cc, cc1;
261 Int32 nNotDone;
262 Int32 nBhtab;
263 UChar* eclass8 = (UChar*)eclass;
264
265 /*--
266 Initial 1-char radix sort to generate
267 initial fmap and initial BH bits.
268 --*/
269 if (verb >= 4)
270 VPrintf0 ( " bucket sorting ...\n" );
271 for (i = 0; i < 257; i++) ftab[i] = 0;
272 for (i = 0; i < nblock; i++) ftab[eclass8[i]]++;
273 for (i = 0; i < 256; i++) ftabCopy[i] = ftab[i];
274 for (i = 1; i < 257; i++) ftab[i] += ftab[i-1];
275
276 for (i = 0; i < nblock; i++) {
277 j = eclass8[i];
278 k = ftab[j] - 1;
279 ftab[j] = k;
280 fmap[k] = i;
281 }
282
283 nBhtab = 2 + (nblock / 32);
284 for (i = 0; i < nBhtab; i++) bhtab[i] = 0;
285 for (i = 0; i < 256; i++) SET_BH(ftab[i]);
286
287 /*--
288 Inductively refine the buckets. Kind-of an
289 "exponential radix sort" (!), inspired by the
290 Manber-Myers suffix array construction algorithm.
291 --*/
292
293 /*-- set sentinel bits for block-end detection --*/
294 for (i = 0; i < 32; i++) {
295 SET_BH(nblock + 2*i);
296 CLEAR_BH(nblock + 2*i + 1);
297 }
298
299 /*-- the log(N) loop --*/
300 H = 1;
301 while (1) {
302
303 if (verb >= 4)
304 VPrintf1 ( " depth %6d has ", H );
305
306 j = 0;
307 for (i = 0; i < nblock; i++) {
308 if (ISSET_BH(i)) j = i;
309 k = fmap[i] - H; if (k < 0) k += nblock;
310 eclass[k] = j;
311 }
312
313 nNotDone = 0;
314 r = -1;
315 while (1) {
316
317 /*-- find the next non-singleton bucket --*/
318 k = r + 1;
319 while (ISSET_BH(k) && UNALIGNED_BH(k)) k++;
320 if (ISSET_BH(k)) {
321 while (WORD_BH(k) == 0xffffffff) k += 32;
322 while (ISSET_BH(k)) k++;
323 }
324 l = k - 1;
325 if (l >= nblock) break;
326 while (!ISSET_BH(k) && UNALIGNED_BH(k)) k++;
327 if (!ISSET_BH(k)) {
328 while (WORD_BH(k) == 0x00000000) k += 32;
329 while (!ISSET_BH(k)) k++;
330 }
331 r = k - 1;
332 if (r >= nblock) break;
333
334 /*-- now [l, r] bracket current bucket --*/
335 if (r > l) {
336 nNotDone += (r - l + 1);
337 fallbackQSort3 ( fmap, eclass, l, r );
338
339 /*-- scan bucket and generate header bits-- */
340 cc = -1;
341 for (i = l; i <= r; i++) {
342 cc1 = eclass[fmap[i]];
343 if (cc != cc1) { SET_BH(i); cc = cc1; };
344 }
345 }
346 }
347
348 if (verb >= 4)
349 VPrintf1 ( "%6d unresolved strings\n", nNotDone );
350
351 H *= 2;
352 if (H > nblock || nNotDone == 0) break;
353 }
354
355 /*--
356 Reconstruct the original block in
357 eclass8 [0 .. nblock-1], since the
358 previous phase destroyed it.
359 --*/
360 if (verb >= 4)
361 VPrintf0 ( " reconstructing block ...\n" );
362 j = 0;
363 for (i = 0; i < nblock; i++) {
364 while (ftabCopy[j] == 0) j++;
365 ftabCopy[j]--;
366 eclass8[fmap[i]] = (UChar)j;
367 }
368 AssertH ( j < 256, 1005 );
369 }
370
371 #undef SET_BH
372 #undef CLEAR_BH
373 #undef ISSET_BH
374 #undef WORD_BH
375 #undef UNALIGNED_BH
376
377
378 /*---------------------------------------------*/
379 /*--- The main, O(N^2 log(N)) sorting ---*/
380 /*--- algorithm. Faster for "normal" ---*/
381 /*--- non-repetitive blocks. ---*/
382 /*---------------------------------------------*/
383
384 /*---------------------------------------------*/
385 static
386 __inline__
mainGtU(UInt32 i1,UInt32 i2,UChar * block,UInt16 * quadrant,UInt32 nblock,Int32 * budget)387 Bool mainGtU ( UInt32 i1,
388 UInt32 i2,
389 UChar* block,
390 UInt16* quadrant,
391 UInt32 nblock,
392 Int32* budget )
393 {
394 Int32 k;
395 UChar c1, c2;
396 UInt16 s1, s2;
397
398 AssertD ( i1 != i2, "mainGtU" );
399 /* 1 */
400 c1 = block[i1]; c2 = block[i2];
401 if (c1 != c2) return (c1 > c2);
402 i1++; i2++;
403 /* 2 */
404 c1 = block[i1]; c2 = block[i2];
405 if (c1 != c2) return (c1 > c2);
406 i1++; i2++;
407 /* 3 */
408 c1 = block[i1]; c2 = block[i2];
409 if (c1 != c2) return (c1 > c2);
410 i1++; i2++;
411 /* 4 */
412 c1 = block[i1]; c2 = block[i2];
413 if (c1 != c2) return (c1 > c2);
414 i1++; i2++;
415 /* 5 */
416 c1 = block[i1]; c2 = block[i2];
417 if (c1 != c2) return (c1 > c2);
418 i1++; i2++;
419 /* 6 */
420 c1 = block[i1]; c2 = block[i2];
421 if (c1 != c2) return (c1 > c2);
422 i1++; i2++;
423 /* 7 */
424 c1 = block[i1]; c2 = block[i2];
425 if (c1 != c2) return (c1 > c2);
426 i1++; i2++;
427 /* 8 */
428 c1 = block[i1]; c2 = block[i2];
429 if (c1 != c2) return (c1 > c2);
430 i1++; i2++;
431 /* 9 */
432 c1 = block[i1]; c2 = block[i2];
433 if (c1 != c2) return (c1 > c2);
434 i1++; i2++;
435 /* 10 */
436 c1 = block[i1]; c2 = block[i2];
437 if (c1 != c2) return (c1 > c2);
438 i1++; i2++;
439 /* 11 */
440 c1 = block[i1]; c2 = block[i2];
441 if (c1 != c2) return (c1 > c2);
442 i1++; i2++;
443 /* 12 */
444 c1 = block[i1]; c2 = block[i2];
445 if (c1 != c2) return (c1 > c2);
446 i1++; i2++;
447
448 k = nblock + 8;
449
450 do {
451 /* 1 */
452 c1 = block[i1]; c2 = block[i2];
453 if (c1 != c2) return (c1 > c2);
454 s1 = quadrant[i1]; s2 = quadrant[i2];
455 if (s1 != s2) return (s1 > s2);
456 i1++; i2++;
457 /* 2 */
458 c1 = block[i1]; c2 = block[i2];
459 if (c1 != c2) return (c1 > c2);
460 s1 = quadrant[i1]; s2 = quadrant[i2];
461 if (s1 != s2) return (s1 > s2);
462 i1++; i2++;
463 /* 3 */
464 c1 = block[i1]; c2 = block[i2];
465 if (c1 != c2) return (c1 > c2);
466 s1 = quadrant[i1]; s2 = quadrant[i2];
467 if (s1 != s2) return (s1 > s2);
468 i1++; i2++;
469 /* 4 */
470 c1 = block[i1]; c2 = block[i2];
471 if (c1 != c2) return (c1 > c2);
472 s1 = quadrant[i1]; s2 = quadrant[i2];
473 if (s1 != s2) return (s1 > s2);
474 i1++; i2++;
475 /* 5 */
476 c1 = block[i1]; c2 = block[i2];
477 if (c1 != c2) return (c1 > c2);
478 s1 = quadrant[i1]; s2 = quadrant[i2];
479 if (s1 != s2) return (s1 > s2);
480 i1++; i2++;
481 /* 6 */
482 c1 = block[i1]; c2 = block[i2];
483 if (c1 != c2) return (c1 > c2);
484 s1 = quadrant[i1]; s2 = quadrant[i2];
485 if (s1 != s2) return (s1 > s2);
486 i1++; i2++;
487 /* 7 */
488 c1 = block[i1]; c2 = block[i2];
489 if (c1 != c2) return (c1 > c2);
490 s1 = quadrant[i1]; s2 = quadrant[i2];
491 if (s1 != s2) return (s1 > s2);
492 i1++; i2++;
493 /* 8 */
494 c1 = block[i1]; c2 = block[i2];
495 if (c1 != c2) return (c1 > c2);
496 s1 = quadrant[i1]; s2 = quadrant[i2];
497 if (s1 != s2) return (s1 > s2);
498 i1++; i2++;
499
500 if (i1 >= nblock) i1 -= nblock;
501 if (i2 >= nblock) i2 -= nblock;
502
503 k -= 8;
504 (*budget)--;
505 }
506 while (k >= 0);
507
508 return False;
509 }
510
511
512 /*---------------------------------------------*/
513 /*--
514 Knuth's increments seem to work better
515 than Incerpi-Sedgewick here. Possibly
516 because the number of elems to sort is
517 usually small, typically <= 20.
518 --*/
519 static
520 Int32 incs[14] = { 1, 4, 13, 40, 121, 364, 1093, 3280,
521 9841, 29524, 88573, 265720,
522 797161, 2391484 };
523
524 static
mainSimpleSort(UInt32 * ptr,UChar * block,UInt16 * quadrant,Int32 nblock,Int32 lo,Int32 hi,Int32 d,Int32 * budget)525 void mainSimpleSort ( UInt32* ptr,
526 UChar* block,
527 UInt16* quadrant,
528 Int32 nblock,
529 Int32 lo,
530 Int32 hi,
531 Int32 d,
532 Int32* budget )
533 {
534 Int32 i, j, h, bigN, hp;
535 UInt32 v;
536
537 bigN = hi - lo + 1;
538 if (bigN < 2) return;
539
540 hp = 0;
541 while (incs[hp] < bigN) hp++;
542 hp--;
543
544 for (; hp >= 0; hp--) {
545 h = incs[hp];
546
547 i = lo + h;
548 while (True) {
549
550 /*-- copy 1 --*/
551 if (i > hi) break;
552 v = ptr[i];
553 j = i;
554 while ( mainGtU (
555 ptr[j-h]+d, v+d, block, quadrant, nblock, budget
556 ) ) {
557 ptr[j] = ptr[j-h];
558 j = j - h;
559 if (j <= (lo + h - 1)) break;
560 }
561 ptr[j] = v;
562 i++;
563
564 /*-- copy 2 --*/
565 if (i > hi) break;
566 v = ptr[i];
567 j = i;
568 while ( mainGtU (
569 ptr[j-h]+d, v+d, block, quadrant, nblock, budget
570 ) ) {
571 ptr[j] = ptr[j-h];
572 j = j - h;
573 if (j <= (lo + h - 1)) break;
574 }
575 ptr[j] = v;
576 i++;
577
578 /*-- copy 3 --*/
579 if (i > hi) break;
580 v = ptr[i];
581 j = i;
582 while ( mainGtU (
583 ptr[j-h]+d, v+d, block, quadrant, nblock, budget
584 ) ) {
585 ptr[j] = ptr[j-h];
586 j = j - h;
587 if (j <= (lo + h - 1)) break;
588 }
589 ptr[j] = v;
590 i++;
591
592 if (*budget < 0) return;
593 }
594 }
595 }
596
597
598 /*---------------------------------------------*/
599 /*--
600 The following is an implementation of
601 an elegant 3-way quicksort for strings,
602 described in a paper "Fast Algorithms for
603 Sorting and Searching Strings", by Robert
604 Sedgewick and Jon L. Bentley.
605 --*/
606
607 #define mswap(zz1, zz2) \
608 { Int32 zztmp = zz1; zz1 = zz2; zz2 = zztmp; }
609
610 #define mvswap(zzp1, zzp2, zzn) \
611 { \
612 Int32 yyp1 = (zzp1); \
613 Int32 yyp2 = (zzp2); \
614 Int32 yyn = (zzn); \
615 while (yyn > 0) { \
616 mswap(ptr[yyp1], ptr[yyp2]); \
617 yyp1++; yyp2++; yyn--; \
618 } \
619 }
620
621 static
622 __inline__
mmed3(UChar a,UChar b,UChar c)623 UChar mmed3 ( UChar a, UChar b, UChar c )
624 {
625 UChar t;
626 if (a > b) { t = a; a = b; b = t; };
627 if (b > c) {
628 b = c;
629 if (a > b) b = a;
630 }
631 return b;
632 }
633
634 #define mmin(a,b) ((a) < (b)) ? (a) : (b)
635
636 #define mpush(lz,hz,dz) { stackLo[sp] = lz; \
637 stackHi[sp] = hz; \
638 stackD [sp] = dz; \
639 sp++; }
640
641 #define mpop(lz,hz,dz) { sp--; \
642 lz = stackLo[sp]; \
643 hz = stackHi[sp]; \
644 dz = stackD [sp]; }
645
646
647 #define mnextsize(az) (nextHi[az]-nextLo[az])
648
649 #define mnextswap(az,bz) \
650 { Int32 tz; \
651 tz = nextLo[az]; nextLo[az] = nextLo[bz]; nextLo[bz] = tz; \
652 tz = nextHi[az]; nextHi[az] = nextHi[bz]; nextHi[bz] = tz; \
653 tz = nextD [az]; nextD [az] = nextD [bz]; nextD [bz] = tz; }
654
655
656 #define MAIN_QSORT_SMALL_THRESH 20
657 #define MAIN_QSORT_DEPTH_THRESH (BZ_N_RADIX + BZ_N_QSORT)
658 #define MAIN_QSORT_STACK_SIZE 100
659
660 static
mainQSort3(UInt32 * ptr,UChar * block,UInt16 * quadrant,Int32 nblock,Int32 loSt,Int32 hiSt,Int32 dSt,Int32 * budget)661 void mainQSort3 ( UInt32* ptr,
662 UChar* block,
663 UInt16* quadrant,
664 Int32 nblock,
665 Int32 loSt,
666 Int32 hiSt,
667 Int32 dSt,
668 Int32* budget )
669 {
670 Int32 unLo, unHi, ltLo, gtHi, n, m, med;
671 Int32 sp, lo, hi, d;
672
673 Int32 stackLo[MAIN_QSORT_STACK_SIZE];
674 Int32 stackHi[MAIN_QSORT_STACK_SIZE];
675 Int32 stackD [MAIN_QSORT_STACK_SIZE];
676
677 Int32 nextLo[3];
678 Int32 nextHi[3];
679 Int32 nextD [3];
680
681 sp = 0;
682 mpush ( loSt, hiSt, dSt );
683
684 while (sp > 0) {
685
686 AssertH ( sp < MAIN_QSORT_STACK_SIZE - 2, 1001 );
687
688 mpop ( lo, hi, d );
689 if (hi - lo < MAIN_QSORT_SMALL_THRESH ||
690 d > MAIN_QSORT_DEPTH_THRESH) {
691 mainSimpleSort ( ptr, block, quadrant, nblock, lo, hi, d, budget );
692 if (*budget < 0) return;
693 continue;
694 }
695
696 med = (Int32)
697 mmed3 ( block[ptr[ lo ]+d],
698 block[ptr[ hi ]+d],
699 block[ptr[ (lo+hi)>>1 ]+d] );
700
701 unLo = ltLo = lo;
702 unHi = gtHi = hi;
703
704 while (True) {
705 while (True) {
706 if (unLo > unHi) break;
707 n = ((Int32)block[ptr[unLo]+d]) - med;
708 if (n == 0) {
709 mswap(ptr[unLo], ptr[ltLo]);
710 ltLo++; unLo++; continue;
711 };
712 if (n > 0) break;
713 unLo++;
714 }
715 while (True) {
716 if (unLo > unHi) break;
717 n = ((Int32)block[ptr[unHi]+d]) - med;
718 if (n == 0) {
719 mswap(ptr[unHi], ptr[gtHi]);
720 gtHi--; unHi--; continue;
721 };
722 if (n < 0) break;
723 unHi--;
724 }
725 if (unLo > unHi) break;
726 mswap(ptr[unLo], ptr[unHi]); unLo++; unHi--;
727 }
728
729 AssertD ( unHi == unLo-1, "mainQSort3(2)" );
730
731 if (gtHi < ltLo) {
732 mpush(lo, hi, d+1 );
733 continue;
734 }
735
736 n = mmin(ltLo-lo, unLo-ltLo); mvswap(lo, unLo-n, n);
737 m = mmin(hi-gtHi, gtHi-unHi); mvswap(unLo, hi-m+1, m);
738
739 n = lo + unLo - ltLo - 1;
740 m = hi - (gtHi - unHi) + 1;
741
742 nextLo[0] = lo; nextHi[0] = n; nextD[0] = d;
743 nextLo[1] = m; nextHi[1] = hi; nextD[1] = d;
744 nextLo[2] = n+1; nextHi[2] = m-1; nextD[2] = d+1;
745
746 if (mnextsize(0) < mnextsize(1)) mnextswap(0,1);
747 if (mnextsize(1) < mnextsize(2)) mnextswap(1,2);
748 if (mnextsize(0) < mnextsize(1)) mnextswap(0,1);
749
750 AssertD (mnextsize(0) >= mnextsize(1), "mainQSort3(8)" );
751 AssertD (mnextsize(1) >= mnextsize(2), "mainQSort3(9)" );
752
753 mpush (nextLo[0], nextHi[0], nextD[0]);
754 mpush (nextLo[1], nextHi[1], nextD[1]);
755 mpush (nextLo[2], nextHi[2], nextD[2]);
756 }
757 }
758
759 #undef mswap
760 #undef mvswap
761 #undef mpush
762 #undef mpop
763 #undef mmin
764 #undef mnextsize
765 #undef mnextswap
766 #undef MAIN_QSORT_SMALL_THRESH
767 #undef MAIN_QSORT_DEPTH_THRESH
768 #undef MAIN_QSORT_STACK_SIZE
769
770
771 /*---------------------------------------------*/
772 /* Pre:
773 nblock > N_OVERSHOOT
774 block32 exists for [0 .. nblock-1 +N_OVERSHOOT]
775 ((UChar*)block32) [0 .. nblock-1] holds block
776 ptr exists for [0 .. nblock-1]
777
778 Post:
779 ((UChar*)block32) [0 .. nblock-1] holds block
780 All other areas of block32 destroyed
781 ftab [0 .. 65536 ] destroyed
782 ptr [0 .. nblock-1] holds sorted order
783 if (*budget < 0), sorting was abandoned
784 */
785
786 #define BIGFREQ(b) (ftab[((b)+1) << 8] - ftab[(b) << 8])
787 #define SETMASK (1 << 21)
788 #define CLEARMASK (~(SETMASK))
789
790 static
mainSort(UInt32 * ptr,UChar * block,UInt16 * quadrant,UInt32 * ftab,Int32 nblock,Int32 verb,Int32 * budget)791 void mainSort ( UInt32* ptr,
792 UChar* block,
793 UInt16* quadrant,
794 UInt32* ftab,
795 Int32 nblock,
796 Int32 verb,
797 Int32* budget )
798 {
799 Int32 i, j, k, ss, sb;
800 Int32 runningOrder[256];
801 Bool bigDone[256];
802 Int32 copyStart[256];
803 Int32 copyEnd [256];
804 UChar c1;
805 Int32 numQSorted;
806 UInt16 s;
807 if (verb >= 4) VPrintf0 ( " main sort initialise ...\n" );
808
809 /*-- set up the 2-byte frequency table --*/
810 for (i = 65536; i >= 0; i--) ftab[i] = 0;
811
812 j = block[0] << 8;
813 i = nblock-1;
814 for (; i >= 3; i -= 4) {
815 quadrant[i] = 0;
816 j = (j >> 8) | ( ((UInt16)block[i]) << 8);
817 ftab[j]++;
818 quadrant[i-1] = 0;
819 j = (j >> 8) | ( ((UInt16)block[i-1]) << 8);
820 ftab[j]++;
821 quadrant[i-2] = 0;
822 j = (j >> 8) | ( ((UInt16)block[i-2]) << 8);
823 ftab[j]++;
824 quadrant[i-3] = 0;
825 j = (j >> 8) | ( ((UInt16)block[i-3]) << 8);
826 ftab[j]++;
827 }
828 for (; i >= 0; i--) {
829 quadrant[i] = 0;
830 j = (j >> 8) | ( ((UInt16)block[i]) << 8);
831 ftab[j]++;
832 }
833
834 /*-- (emphasises close relationship of block & quadrant) --*/
835 for (i = 0; i < BZ_N_OVERSHOOT; i++) {
836 block [nblock+i] = block[i];
837 quadrant[nblock+i] = 0;
838 }
839
840 if (verb >= 4) VPrintf0 ( " bucket sorting ...\n" );
841
842 /*-- Complete the initial radix sort --*/
843 for (i = 1; i <= 65536; i++) ftab[i] += ftab[i-1];
844
845 s = block[0] << 8;
846 i = nblock-1;
847 for (; i >= 3; i -= 4) {
848 s = (s >> 8) | (block[i] << 8);
849 j = ftab[s] -1;
850 ftab[s] = j;
851 ptr[j] = i;
852 s = (s >> 8) | (block[i-1] << 8);
853 j = ftab[s] -1;
854 ftab[s] = j;
855 ptr[j] = i-1;
856 s = (s >> 8) | (block[i-2] << 8);
857 j = ftab[s] -1;
858 ftab[s] = j;
859 ptr[j] = i-2;
860 s = (s >> 8) | (block[i-3] << 8);
861 j = ftab[s] -1;
862 ftab[s] = j;
863 ptr[j] = i-3;
864 }
865 for (; i >= 0; i--) {
866 s = (s >> 8) | (block[i] << 8);
867 j = ftab[s] -1;
868 ftab[s] = j;
869 ptr[j] = i;
870 }
871
872 /*--
873 Now ftab contains the first loc of every small bucket.
874 Calculate the running order, from smallest to largest
875 big bucket.
876 --*/
877 for (i = 0; i <= 255; i++) {
878 bigDone [i] = False;
879 runningOrder[i] = i;
880 }
881
882 {
883 Int32 vv;
884 Int32 h = 1;
885 do h = 3 * h + 1; while (h <= 256);
886 do {
887 h = h / 3;
888 for (i = h; i <= 255; i++) {
889 vv = runningOrder[i];
890 j = i;
891 while ( BIGFREQ(runningOrder[j-h]) > BIGFREQ(vv) ) {
892 runningOrder[j] = runningOrder[j-h];
893 j = j - h;
894 if (j <= (h - 1)) goto zero;
895 }
896 zero:
897 runningOrder[j] = vv;
898 }
899 } while (h != 1);
900 }
901
902 /*--
903 The main sorting loop.
904 --*/
905
906 numQSorted = 0;
907
908 for (i = 0; i <= 255; i++) {
909
910 /*--
911 Process big buckets, starting with the least full.
912 Basically this is a 3-step process in which we call
913 mainQSort3 to sort the small buckets [ss, j], but
914 also make a big effort to avoid the calls if we can.
915 --*/
916 ss = runningOrder[i];
917
918 /*--
919 Step 1:
920 Complete the big bucket [ss] by quicksorting
921 any unsorted small buckets [ss, j], for j != ss.
922 Hopefully previous pointer-scanning phases have already
923 completed many of the small buckets [ss, j], so
924 we don't have to sort them at all.
925 --*/
926 for (j = 0; j <= 255; j++) {
927 if (j != ss) {
928 sb = (ss << 8) + j;
929 if ( ! (ftab[sb] & SETMASK) ) {
930 Int32 lo = ftab[sb] & CLEARMASK;
931 Int32 hi = (ftab[sb+1] & CLEARMASK) - 1;
932 if (hi > lo) {
933 if (verb >= 4)
934 VPrintf4 ( " qsort [0x%x, 0x%x] "
935 "done %d this %d\n",
936 ss, j, numQSorted, hi - lo + 1 );
937 mainQSort3 (
938 ptr, block, quadrant, nblock,
939 lo, hi, BZ_N_RADIX, budget
940 );
941 numQSorted += (hi - lo + 1);
942 if (*budget < 0) return;
943 }
944 }
945 ftab[sb] |= SETMASK;
946 }
947 }
948
949 AssertH ( !bigDone[ss], 1006 );
950
951 /*--
952 Step 2:
953 Now scan this big bucket [ss] so as to synthesise the
954 sorted order for small buckets [t, ss] for all t,
955 including, magically, the bucket [ss,ss] too.
956 This will avoid doing Real Work in subsequent Step 1's.
957 --*/
958 {
959 for (j = 0; j <= 255; j++) {
960 copyStart[j] = ftab[(j << 8) + ss] & CLEARMASK;
961 copyEnd [j] = (ftab[(j << 8) + ss + 1] & CLEARMASK) - 1;
962 }
963 for (j = ftab[ss << 8] & CLEARMASK; j < copyStart[ss]; j++) {
964 k = ptr[j]-1; if (k < 0) k += nblock;
965 c1 = block[k];
966 if (!bigDone[c1])
967 ptr[ copyStart[c1]++ ] = k;
968 }
969 for (j = (ftab[(ss+1) << 8] & CLEARMASK) - 1; j > copyEnd[ss]; j--) {
970 k = ptr[j]-1; if (k < 0) k += nblock;
971 c1 = block[k];
972 if (!bigDone[c1])
973 ptr[ copyEnd[c1]-- ] = k;
974 }
975 }
976
977 AssertH ( (copyStart[ss]-1 == copyEnd[ss])
978 ||
979 /* Extremely rare case missing in bzip2-1.0.0 and 1.0.1.
980 Necessity for this case is demonstrated by compressing
981 a sequence of approximately 48.5 million of character
982 251; 1.0.0/1.0.1 will then die here. */
983 (copyStart[ss] == 0 && copyEnd[ss] == nblock-1),
984 1007 )
985
986 for (j = 0; j <= 255; j++) ftab[(j << 8) + ss] |= SETMASK;
987
988 /*--
989 Step 3:
990 The [ss] big bucket is now done. Record this fact,
991 and update the quadrant descriptors. Remember to
992 update quadrants in the overshoot area too, if
993 necessary. The "if (i < 255)" test merely skips
994 this updating for the last bucket processed, since
995 updating for the last bucket is pointless.
996
997 The quadrant array provides a way to incrementally
998 cache sort orderings, as they appear, so as to
999 make subsequent comparisons in fullGtU() complete
1000 faster. For repetitive blocks this makes a big
1001 difference (but not big enough to be able to avoid
1002 the fallback sorting mechanism, exponential radix sort).
1003
1004 The precise meaning is: at all times:
1005
1006 for 0 <= i < nblock and 0 <= j <= nblock
1007
1008 if block[i] != block[j],
1009
1010 then the relative values of quadrant[i] and
1011 quadrant[j] are meaningless.
1012
1013 else {
1014 if quadrant[i] < quadrant[j]
1015 then the string starting at i lexicographically
1016 precedes the string starting at j
1017
1018 else if quadrant[i] > quadrant[j]
1019 then the string starting at j lexicographically
1020 precedes the string starting at i
1021
1022 else
1023 the relative ordering of the strings starting
1024 at i and j has not yet been determined.
1025 }
1026 --*/
1027 bigDone[ss] = True;
1028
1029 if (i < 255) {
1030 Int32 bbStart = ftab[ss << 8] & CLEARMASK;
1031 Int32 bbSize = (ftab[(ss+1) << 8] & CLEARMASK) - bbStart;
1032 Int32 shifts = 0;
1033
1034 while ((bbSize >> shifts) > 65534) shifts++;
1035
1036 for (j = bbSize-1; j >= 0; j--) {
1037 Int32 a2update = ptr[bbStart + j];
1038 UInt16 qVal = (UInt16)(j >> shifts);
1039 quadrant[a2update] = qVal;
1040 if (a2update < BZ_N_OVERSHOOT)
1041 quadrant[a2update + nblock] = qVal;
1042 }
1043 AssertH ( ((bbSize-1) >> shifts) <= 65535, 1002 );
1044 }
1045
1046 }
1047
1048 if (verb >= 4)
1049 VPrintf3 ( " %d pointers, %d sorted, %d scanned\n",
1050 nblock, numQSorted, nblock - numQSorted );
1051 }
1052
1053 #undef BIGFREQ
1054 #undef SETMASK
1055 #undef CLEARMASK
1056
1057
1058 /*---------------------------------------------*/
1059 /* Pre:
1060 nblock > 0
1061 arr2 exists for [0 .. nblock-1 +N_OVERSHOOT]
1062 ((UChar*)arr2) [0 .. nblock-1] holds block
1063 arr1 exists for [0 .. nblock-1]
1064
1065 Post:
1066 ((UChar*)arr2) [0 .. nblock-1] holds block
1067 All other areas of block destroyed
1068 ftab [ 0 .. 65536 ] destroyed
1069 arr1 [0 .. nblock-1] holds sorted order
1070 */
BZ2_blockSort(EState * s)1071 void BZ2_blockSort ( EState* s )
1072 {
1073 UInt32* ptr = s->ptr;
1074 UChar* block = s->block;
1075 UInt32* ftab = s->ftab;
1076 Int32 nblock = s->nblock;
1077 Int32 verb = s->verbosity;
1078 Int32 wfact = s->workFactor;
1079 UInt16* quadrant;
1080 Int32 budget;
1081 Int32 budgetInit;
1082 Int32 i;
1083
1084 if (nblock < 10000) {
1085 fallbackSort ( s->arr1, s->arr2, ftab, nblock, verb );
1086 } else {
1087 /* Calculate the location for quadrant, remembering to get
1088 the alignment right. Assumes that &(block[0]) is at least
1089 2-byte aligned -- this should be ok since block is really
1090 the first section of arr2.
1091 */
1092 i = nblock+BZ_N_OVERSHOOT;
1093 if (i & 1) i++;
1094 quadrant = (UInt16*)(&(block[i]));
1095
1096 /* (wfact-1) / 3 puts the default-factor-30
1097 transition point at very roughly the same place as
1098 with v0.1 and v0.9.0.
1099 Not that it particularly matters any more, since the
1100 resulting compressed stream is now the same regardless
1101 of whether or not we use the main sort or fallback sort.
1102 */
1103 if (wfact < 1 ) wfact = 1;
1104 if (wfact > 100) wfact = 100;
1105 budgetInit = nblock * ((wfact-1) / 3);
1106 budget = budgetInit;
1107
1108 mainSort ( ptr, block, quadrant, ftab, nblock, verb, &budget );
1109 if (verb >= 3)
1110 VPrintf3 ( " %d work, %d block, ratio %5.2f\n",
1111 budgetInit - budget,
1112 nblock,
1113 (float)(budgetInit - budget) /
1114 (float)(nblock==0 ? 1 : nblock) );
1115 if (budget < 0) {
1116 if (verb >= 2)
1117 VPrintf0 ( " too repetitive; using fallback"
1118 " sorting algorithm\n" );
1119 fallbackSort ( s->arr1, s->arr2, ftab, nblock, verb );
1120 }
1121 }
1122
1123 s->origPtr = -1;
1124 for (i = 0; i < s->nblock; i++)
1125 if (ptr[i] == 0)
1126 { s->origPtr = i; break; };
1127
1128 AssertH( s->origPtr != -1, 1003 );
1129 }
1130
1131
1132 /*-------------------------------------------------------------*/
1133 /*--- end blocksort.c ---*/
1134 /*-------------------------------------------------------------*/
1135