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comparison perl-5.22.2/pp_sort.c @ 8045:a16537d2fe07
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author | HackBot |
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date | Sat, 14 May 2016 14:54:38 +0000 |
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1 /* pp_sort.c | |
2 * | |
3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, | |
4 * 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others | |
5 * | |
6 * You may distribute under the terms of either the GNU General Public | |
7 * License or the Artistic License, as specified in the README file. | |
8 * | |
9 */ | |
10 | |
11 /* | |
12 * ...they shuffled back towards the rear of the line. 'No, not at the | |
13 * rear!' the slave-driver shouted. 'Three files up. And stay there... | |
14 * | |
15 * [p.931 of _The Lord of the Rings_, VI/ii: "The Land of Shadow"] | |
16 */ | |
17 | |
18 /* This file contains pp ("push/pop") functions that | |
19 * execute the opcodes that make up a perl program. A typical pp function | |
20 * expects to find its arguments on the stack, and usually pushes its | |
21 * results onto the stack, hence the 'pp' terminology. Each OP structure | |
22 * contains a pointer to the relevant pp_foo() function. | |
23 * | |
24 * This particular file just contains pp_sort(), which is complex | |
25 * enough to merit its own file! See the other pp*.c files for the rest of | |
26 * the pp_ functions. | |
27 */ | |
28 | |
29 #include "EXTERN.h" | |
30 #define PERL_IN_PP_SORT_C | |
31 #include "perl.h" | |
32 | |
33 #if defined(UNDER_CE) | |
34 /* looks like 'small' is reserved word for WINCE (or somesuch)*/ | |
35 #define small xsmall | |
36 #endif | |
37 | |
38 #define sv_cmp_static Perl_sv_cmp | |
39 #define sv_cmp_locale_static Perl_sv_cmp_locale | |
40 | |
41 #ifndef SMALLSORT | |
42 #define SMALLSORT (200) | |
43 #endif | |
44 | |
45 /* Flags for qsortsv and mergesortsv */ | |
46 #define SORTf_DESC 1 | |
47 #define SORTf_STABLE 2 | |
48 #define SORTf_QSORT 4 | |
49 | |
50 /* | |
51 * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>. | |
52 * | |
53 * The original code was written in conjunction with BSD Computer Software | |
54 * Research Group at University of California, Berkeley. | |
55 * | |
56 * See also: "Optimistic Sorting and Information Theoretic Complexity" | |
57 * Peter McIlroy | |
58 * SODA (Fourth Annual ACM-SIAM Symposium on Discrete Algorithms), | |
59 * pp 467-474, Austin, Texas, 25-27 January 1993. | |
60 * | |
61 * The integration to Perl is by John P. Linderman <jpl.jpl@gmail.com>. | |
62 * | |
63 * The code can be distributed under the same terms as Perl itself. | |
64 * | |
65 */ | |
66 | |
67 | |
68 typedef char * aptr; /* pointer for arithmetic on sizes */ | |
69 typedef SV * gptr; /* pointers in our lists */ | |
70 | |
71 /* Binary merge internal sort, with a few special mods | |
72 ** for the special perl environment it now finds itself in. | |
73 ** | |
74 ** Things that were once options have been hotwired | |
75 ** to values suitable for this use. In particular, we'll always | |
76 ** initialize looking for natural runs, we'll always produce stable | |
77 ** output, and we'll always do Peter McIlroy's binary merge. | |
78 */ | |
79 | |
80 /* Pointer types for arithmetic and storage and convenience casts */ | |
81 | |
82 #define APTR(P) ((aptr)(P)) | |
83 #define GPTP(P) ((gptr *)(P)) | |
84 #define GPPP(P) ((gptr **)(P)) | |
85 | |
86 | |
87 /* byte offset from pointer P to (larger) pointer Q */ | |
88 #define BYTEOFF(P, Q) (APTR(Q) - APTR(P)) | |
89 | |
90 #define PSIZE sizeof(gptr) | |
91 | |
92 /* If PSIZE is power of 2, make PSHIFT that power, if that helps */ | |
93 | |
94 #ifdef PSHIFT | |
95 #define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT)) | |
96 #define PNBYTE(N) ((N) << (PSHIFT)) | |
97 #define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N))) | |
98 #else | |
99 /* Leave optimization to compiler */ | |
100 #define PNELEM(P, Q) (GPTP(Q) - GPTP(P)) | |
101 #define PNBYTE(N) ((N) * (PSIZE)) | |
102 #define PINDEX(P, N) (GPTP(P) + (N)) | |
103 #endif | |
104 | |
105 /* Pointer into other corresponding to pointer into this */ | |
106 #define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P)) | |
107 | |
108 #define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim) | |
109 | |
110 | |
111 /* Runs are identified by a pointer in the auxiliary list. | |
112 ** The pointer is at the start of the list, | |
113 ** and it points to the start of the next list. | |
114 ** NEXT is used as an lvalue, too. | |
115 */ | |
116 | |
117 #define NEXT(P) (*GPPP(P)) | |
118 | |
119 | |
120 /* PTHRESH is the minimum number of pairs with the same sense to justify | |
121 ** checking for a run and extending it. Note that PTHRESH counts PAIRS, | |
122 ** not just elements, so PTHRESH == 8 means a run of 16. | |
123 */ | |
124 | |
125 #define PTHRESH (8) | |
126 | |
127 /* RTHRESH is the number of elements in a run that must compare low | |
128 ** to the low element from the opposing run before we justify | |
129 ** doing a binary rampup instead of single stepping. | |
130 ** In random input, N in a row low should only happen with | |
131 ** probability 2^(1-N), so we can risk that we are dealing | |
132 ** with orderly input without paying much when we aren't. | |
133 */ | |
134 | |
135 #define RTHRESH (6) | |
136 | |
137 | |
138 /* | |
139 ** Overview of algorithm and variables. | |
140 ** The array of elements at list1 will be organized into runs of length 2, | |
141 ** or runs of length >= 2 * PTHRESH. We only try to form long runs when | |
142 ** PTHRESH adjacent pairs compare in the same way, suggesting overall order. | |
143 ** | |
144 ** Unless otherwise specified, pair pointers address the first of two elements. | |
145 ** | |
146 ** b and b+1 are a pair that compare with sense "sense". | |
147 ** b is the "bottom" of adjacent pairs that might form a longer run. | |
148 ** | |
149 ** p2 parallels b in the list2 array, where runs are defined by | |
150 ** a pointer chain. | |
151 ** | |
152 ** t represents the "top" of the adjacent pairs that might extend | |
153 ** the run beginning at b. Usually, t addresses a pair | |
154 ** that compares with opposite sense from (b,b+1). | |
155 ** However, it may also address a singleton element at the end of list1, | |
156 ** or it may be equal to "last", the first element beyond list1. | |
157 ** | |
158 ** r addresses the Nth pair following b. If this would be beyond t, | |
159 ** we back it off to t. Only when r is less than t do we consider the | |
160 ** run long enough to consider checking. | |
161 ** | |
162 ** q addresses a pair such that the pairs at b through q already form a run. | |
163 ** Often, q will equal b, indicating we only are sure of the pair itself. | |
164 ** However, a search on the previous cycle may have revealed a longer run, | |
165 ** so q may be greater than b. | |
166 ** | |
167 ** p is used to work back from a candidate r, trying to reach q, | |
168 ** which would mean b through r would be a run. If we discover such a run, | |
169 ** we start q at r and try to push it further towards t. | |
170 ** If b through r is NOT a run, we detect the wrong order at (p-1,p). | |
171 ** In any event, after the check (if any), we have two main cases. | |
172 ** | |
173 ** 1) Short run. b <= q < p <= r <= t. | |
174 ** b through q is a run (perhaps trivial) | |
175 ** q through p are uninteresting pairs | |
176 ** p through r is a run | |
177 ** | |
178 ** 2) Long run. b < r <= q < t. | |
179 ** b through q is a run (of length >= 2 * PTHRESH) | |
180 ** | |
181 ** Note that degenerate cases are not only possible, but likely. | |
182 ** For example, if the pair following b compares with opposite sense, | |
183 ** then b == q < p == r == t. | |
184 */ | |
185 | |
186 | |
187 static IV | |
188 dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, const SVCOMPARE_t cmp) | |
189 { | |
190 I32 sense; | |
191 gptr *b, *p, *q, *t, *p2; | |
192 gptr *last, *r; | |
193 IV runs = 0; | |
194 | |
195 b = list1; | |
196 last = PINDEX(b, nmemb); | |
197 sense = (cmp(aTHX_ *b, *(b+1)) > 0); | |
198 for (p2 = list2; b < last; ) { | |
199 /* We just started, or just reversed sense. | |
200 ** Set t at end of pairs with the prevailing sense. | |
201 */ | |
202 for (p = b+2, t = p; ++p < last; t = ++p) { | |
203 if ((cmp(aTHX_ *t, *p) > 0) != sense) break; | |
204 } | |
205 q = b; | |
206 /* Having laid out the playing field, look for long runs */ | |
207 do { | |
208 p = r = b + (2 * PTHRESH); | |
209 if (r >= t) p = r = t; /* too short to care about */ | |
210 else { | |
211 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) && | |
212 ((p -= 2) > q)) {} | |
213 if (p <= q) { | |
214 /* b through r is a (long) run. | |
215 ** Extend it as far as possible. | |
216 */ | |
217 p = q = r; | |
218 while (((p += 2) < t) && | |
219 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p; | |
220 r = p = q + 2; /* no simple pairs, no after-run */ | |
221 } | |
222 } | |
223 if (q > b) { /* run of greater than 2 at b */ | |
224 gptr *savep = p; | |
225 | |
226 p = q += 2; | |
227 /* pick up singleton, if possible */ | |
228 if ((p == t) && | |
229 ((t + 1) == last) && | |
230 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) | |
231 savep = r = p = q = last; | |
232 p2 = NEXT(p2) = p2 + (p - b); ++runs; | |
233 if (sense) | |
234 while (b < --p) { | |
235 const gptr c = *b; | |
236 *b++ = *p; | |
237 *p = c; | |
238 } | |
239 p = savep; | |
240 } | |
241 while (q < p) { /* simple pairs */ | |
242 p2 = NEXT(p2) = p2 + 2; ++runs; | |
243 if (sense) { | |
244 const gptr c = *q++; | |
245 *(q-1) = *q; | |
246 *q++ = c; | |
247 } else q += 2; | |
248 } | |
249 if (((b = p) == t) && ((t+1) == last)) { | |
250 NEXT(p2) = p2 + 1; ++runs; | |
251 b++; | |
252 } | |
253 q = r; | |
254 } while (b < t); | |
255 sense = !sense; | |
256 } | |
257 return runs; | |
258 } | |
259 | |
260 | |
261 /* The original merge sort, in use since 5.7, was as fast as, or faster than, | |
262 * qsort on many platforms, but slower than qsort, conspicuously so, | |
263 * on others. The most likely explanation was platform-specific | |
264 * differences in cache sizes and relative speeds. | |
265 * | |
266 * The quicksort divide-and-conquer algorithm guarantees that, as the | |
267 * problem is subdivided into smaller and smaller parts, the parts | |
268 * fit into smaller (and faster) caches. So it doesn't matter how | |
269 * many levels of cache exist, quicksort will "find" them, and, | |
270 * as long as smaller is faster, take advantage of them. | |
271 * | |
272 * By contrast, consider how the original mergesort algorithm worked. | |
273 * Suppose we have five runs (each typically of length 2 after dynprep). | |
274 * | |
275 * pass base aux | |
276 * 0 1 2 3 4 5 | |
277 * 1 12 34 5 | |
278 * 2 1234 5 | |
279 * 3 12345 | |
280 * 4 12345 | |
281 * | |
282 * Adjacent pairs are merged in "grand sweeps" through the input. | |
283 * This means, on pass 1, the records in runs 1 and 2 aren't revisited until | |
284 * runs 3 and 4 are merged and the runs from run 5 have been copied. | |
285 * The only cache that matters is one large enough to hold *all* the input. | |
286 * On some platforms, this may be many times slower than smaller caches. | |
287 * | |
288 * The following pseudo-code uses the same basic merge algorithm, | |
289 * but in a divide-and-conquer way. | |
290 * | |
291 * # merge $runs runs at offset $offset of list $list1 into $list2. | |
292 * # all unmerged runs ($runs == 1) originate in list $base. | |
293 * sub mgsort2 { | |
294 * my ($offset, $runs, $base, $list1, $list2) = @_; | |
295 * | |
296 * if ($runs == 1) { | |
297 * if ($list1 is $base) copy run to $list2 | |
298 * return offset of end of list (or copy) | |
299 * } else { | |
300 * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1) | |
301 * mgsort2($off2, $runs/2, $base, $list2, $list1) | |
302 * merge the adjacent runs at $offset of $list1 into $list2 | |
303 * return the offset of the end of the merged runs | |
304 * } | |
305 * } | |
306 * mgsort2(0, $runs, $base, $aux, $base); | |
307 * | |
308 * For our 5 runs, the tree of calls looks like | |
309 * | |
310 * 5 | |
311 * 3 2 | |
312 * 2 1 1 1 | |
313 * 1 1 | |
314 * | |
315 * 1 2 3 4 5 | |
316 * | |
317 * and the corresponding activity looks like | |
318 * | |
319 * copy runs 1 and 2 from base to aux | |
320 * merge runs 1 and 2 from aux to base | |
321 * (run 3 is where it belongs, no copy needed) | |
322 * merge runs 12 and 3 from base to aux | |
323 * (runs 4 and 5 are where they belong, no copy needed) | |
324 * merge runs 4 and 5 from base to aux | |
325 * merge runs 123 and 45 from aux to base | |
326 * | |
327 * Note that we merge runs 1 and 2 immediately after copying them, | |
328 * while they are still likely to be in fast cache. Similarly, | |
329 * run 3 is merged with run 12 while it still may be lingering in cache. | |
330 * This implementation should therefore enjoy much of the cache-friendly | |
331 * behavior that quicksort does. In addition, it does less copying | |
332 * than the original mergesort implementation (only runs 1 and 2 are copied) | |
333 * and the "balancing" of merges is better (merged runs comprise more nearly | |
334 * equal numbers of original runs). | |
335 * | |
336 * The actual cache-friendly implementation will use a pseudo-stack | |
337 * to avoid recursion, and will unroll processing of runs of length 2, | |
338 * but it is otherwise similar to the recursive implementation. | |
339 */ | |
340 | |
341 typedef struct { | |
342 IV offset; /* offset of 1st of 2 runs at this level */ | |
343 IV runs; /* how many runs must be combined into 1 */ | |
344 } off_runs; /* pseudo-stack element */ | |
345 | |
346 | |
347 static I32 | |
348 cmp_desc(pTHX_ gptr const a, gptr const b) | |
349 { | |
350 return -PL_sort_RealCmp(aTHX_ a, b); | |
351 } | |
352 | |
353 STATIC void | |
354 S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp, U32 flags) | |
355 { | |
356 IV i, run, offset; | |
357 I32 sense, level; | |
358 gptr *f1, *f2, *t, *b, *p; | |
359 int iwhich; | |
360 gptr *aux; | |
361 gptr *p1; | |
362 gptr small[SMALLSORT]; | |
363 gptr *which[3]; | |
364 off_runs stack[60], *stackp; | |
365 SVCOMPARE_t savecmp = NULL; | |
366 | |
367 if (nmemb <= 1) return; /* sorted trivially */ | |
368 | |
369 if ((flags & SORTf_DESC) != 0) { | |
370 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ | |
371 PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */ | |
372 cmp = cmp_desc; | |
373 } | |
374 | |
375 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */ | |
376 else { Newx(aux,nmemb,gptr); } /* allocate auxiliary array */ | |
377 level = 0; | |
378 stackp = stack; | |
379 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp); | |
380 stackp->offset = offset = 0; | |
381 which[0] = which[2] = base; | |
382 which[1] = aux; | |
383 for (;;) { | |
384 /* On levels where both runs have be constructed (stackp->runs == 0), | |
385 * merge them, and note the offset of their end, in case the offset | |
386 * is needed at the next level up. Hop up a level, and, | |
387 * as long as stackp->runs is 0, keep merging. | |
388 */ | |
389 IV runs = stackp->runs; | |
390 if (runs == 0) { | |
391 gptr *list1, *list2; | |
392 iwhich = level & 1; | |
393 list1 = which[iwhich]; /* area where runs are now */ | |
394 list2 = which[++iwhich]; /* area for merged runs */ | |
395 do { | |
396 gptr *l1, *l2, *tp2; | |
397 offset = stackp->offset; | |
398 f1 = p1 = list1 + offset; /* start of first run */ | |
399 p = tp2 = list2 + offset; /* where merged run will go */ | |
400 t = NEXT(p); /* where first run ends */ | |
401 f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */ | |
402 t = NEXT(t); /* where second runs ends */ | |
403 l2 = POTHER(t, list2, list1); /* ... on the other side */ | |
404 offset = PNELEM(list2, t); | |
405 while (f1 < l1 && f2 < l2) { | |
406 /* If head 1 is larger than head 2, find ALL the elements | |
407 ** in list 2 strictly less than head1, write them all, | |
408 ** then head 1. Then compare the new heads, and repeat, | |
409 ** until one or both lists are exhausted. | |
410 ** | |
411 ** In all comparisons (after establishing | |
412 ** which head to merge) the item to merge | |
413 ** (at pointer q) is the first operand of | |
414 ** the comparison. When we want to know | |
415 ** if "q is strictly less than the other", | |
416 ** we can't just do | |
417 ** cmp(q, other) < 0 | |
418 ** because stability demands that we treat equality | |
419 ** as high when q comes from l2, and as low when | |
420 ** q was from l1. So we ask the question by doing | |
421 ** cmp(q, other) <= sense | |
422 ** and make sense == 0 when equality should look low, | |
423 ** and -1 when equality should look high. | |
424 */ | |
425 | |
426 gptr *q; | |
427 if (cmp(aTHX_ *f1, *f2) <= 0) { | |
428 q = f2; b = f1; t = l1; | |
429 sense = -1; | |
430 } else { | |
431 q = f1; b = f2; t = l2; | |
432 sense = 0; | |
433 } | |
434 | |
435 | |
436 /* ramp up | |
437 ** | |
438 ** Leave t at something strictly | |
439 ** greater than q (or at the end of the list), | |
440 ** and b at something strictly less than q. | |
441 */ | |
442 for (i = 1, run = 0 ;;) { | |
443 if ((p = PINDEX(b, i)) >= t) { | |
444 /* off the end */ | |
445 if (((p = PINDEX(t, -1)) > b) && | |
446 (cmp(aTHX_ *q, *p) <= sense)) | |
447 t = p; | |
448 else b = p; | |
449 break; | |
450 } else if (cmp(aTHX_ *q, *p) <= sense) { | |
451 t = p; | |
452 break; | |
453 } else b = p; | |
454 if (++run >= RTHRESH) i += i; | |
455 } | |
456 | |
457 | |
458 /* q is known to follow b and must be inserted before t. | |
459 ** Increment b, so the range of possibilities is [b,t). | |
460 ** Round binary split down, to favor early appearance. | |
461 ** Adjust b and t until q belongs just before t. | |
462 */ | |
463 | |
464 b++; | |
465 while (b < t) { | |
466 p = PINDEX(b, (PNELEM(b, t) - 1) / 2); | |
467 if (cmp(aTHX_ *q, *p) <= sense) { | |
468 t = p; | |
469 } else b = p + 1; | |
470 } | |
471 | |
472 | |
473 /* Copy all the strictly low elements */ | |
474 | |
475 if (q == f1) { | |
476 FROMTOUPTO(f2, tp2, t); | |
477 *tp2++ = *f1++; | |
478 } else { | |
479 FROMTOUPTO(f1, tp2, t); | |
480 *tp2++ = *f2++; | |
481 } | |
482 } | |
483 | |
484 | |
485 /* Run out remaining list */ | |
486 if (f1 == l1) { | |
487 if (f2 < l2) FROMTOUPTO(f2, tp2, l2); | |
488 } else FROMTOUPTO(f1, tp2, l1); | |
489 p1 = NEXT(p1) = POTHER(tp2, list2, list1); | |
490 | |
491 if (--level == 0) goto done; | |
492 --stackp; | |
493 t = list1; list1 = list2; list2 = t; /* swap lists */ | |
494 } while ((runs = stackp->runs) == 0); | |
495 } | |
496 | |
497 | |
498 stackp->runs = 0; /* current run will finish level */ | |
499 /* While there are more than 2 runs remaining, | |
500 * turn them into exactly 2 runs (at the "other" level), | |
501 * each made up of approximately half the runs. | |
502 * Stack the second half for later processing, | |
503 * and set about producing the first half now. | |
504 */ | |
505 while (runs > 2) { | |
506 ++level; | |
507 ++stackp; | |
508 stackp->offset = offset; | |
509 runs -= stackp->runs = runs / 2; | |
510 } | |
511 /* We must construct a single run from 1 or 2 runs. | |
512 * All the original runs are in which[0] == base. | |
513 * The run we construct must end up in which[level&1]. | |
514 */ | |
515 iwhich = level & 1; | |
516 if (runs == 1) { | |
517 /* Constructing a single run from a single run. | |
518 * If it's where it belongs already, there's nothing to do. | |
519 * Otherwise, copy it to where it belongs. | |
520 * A run of 1 is either a singleton at level 0, | |
521 * or the second half of a split 3. In neither event | |
522 * is it necessary to set offset. It will be set by the merge | |
523 * that immediately follows. | |
524 */ | |
525 if (iwhich) { /* Belongs in aux, currently in base */ | |
526 f1 = b = PINDEX(base, offset); /* where list starts */ | |
527 f2 = PINDEX(aux, offset); /* where list goes */ | |
528 t = NEXT(f2); /* where list will end */ | |
529 offset = PNELEM(aux, t); /* offset thereof */ | |
530 t = PINDEX(base, offset); /* where it currently ends */ | |
531 FROMTOUPTO(f1, f2, t); /* copy */ | |
532 NEXT(b) = t; /* set up parallel pointer */ | |
533 } else if (level == 0) goto done; /* single run at level 0 */ | |
534 } else { | |
535 /* Constructing a single run from two runs. | |
536 * The merge code at the top will do that. | |
537 * We need only make sure the two runs are in the "other" array, | |
538 * so they'll end up in the correct array after the merge. | |
539 */ | |
540 ++level; | |
541 ++stackp; | |
542 stackp->offset = offset; | |
543 stackp->runs = 0; /* take care of both runs, trigger merge */ | |
544 if (!iwhich) { /* Merged runs belong in aux, copy 1st */ | |
545 f1 = b = PINDEX(base, offset); /* where first run starts */ | |
546 f2 = PINDEX(aux, offset); /* where it will be copied */ | |
547 t = NEXT(f2); /* where first run will end */ | |
548 offset = PNELEM(aux, t); /* offset thereof */ | |
549 p = PINDEX(base, offset); /* end of first run */ | |
550 t = NEXT(t); /* where second run will end */ | |
551 t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */ | |
552 FROMTOUPTO(f1, f2, t); /* copy both runs */ | |
553 NEXT(b) = p; /* paralleled pointer for 1st */ | |
554 NEXT(p) = t; /* ... and for second */ | |
555 } | |
556 } | |
557 } | |
558 done: | |
559 if (aux != small) Safefree(aux); /* free iff allocated */ | |
560 if (flags) { | |
561 PL_sort_RealCmp = savecmp; /* Restore current comparison routine, if any */ | |
562 } | |
563 return; | |
564 } | |
565 | |
566 /* | |
567 * The quicksort implementation was derived from source code contributed | |
568 * by Tom Horsley. | |
569 * | |
570 * NOTE: this code was derived from Tom Horsley's qsort replacement | |
571 * and should not be confused with the original code. | |
572 */ | |
573 | |
574 /* Copyright (C) Tom Horsley, 1997. All rights reserved. | |
575 | |
576 Permission granted to distribute under the same terms as perl which are | |
577 (briefly): | |
578 | |
579 This program is free software; you can redistribute it and/or modify | |
580 it under the terms of either: | |
581 | |
582 a) the GNU General Public License as published by the Free | |
583 Software Foundation; either version 1, or (at your option) any | |
584 later version, or | |
585 | |
586 b) the "Artistic License" which comes with this Kit. | |
587 | |
588 Details on the perl license can be found in the perl source code which | |
589 may be located via the www.perl.com web page. | |
590 | |
591 This is the most wonderfulest possible qsort I can come up with (and | |
592 still be mostly portable) My (limited) tests indicate it consistently | |
593 does about 20% fewer calls to compare than does the qsort in the Visual | |
594 C++ library, other vendors may vary. | |
595 | |
596 Some of the ideas in here can be found in "Algorithms" by Sedgewick, | |
597 others I invented myself (or more likely re-invented since they seemed | |
598 pretty obvious once I watched the algorithm operate for a while). | |
599 | |
600 Most of this code was written while watching the Marlins sweep the Giants | |
601 in the 1997 National League Playoffs - no Braves fans allowed to use this | |
602 code (just kidding :-). | |
603 | |
604 I realize that if I wanted to be true to the perl tradition, the only | |
605 comment in this file would be something like: | |
606 | |
607 ...they shuffled back towards the rear of the line. 'No, not at the | |
608 rear!' the slave-driver shouted. 'Three files up. And stay there... | |
609 | |
610 However, I really needed to violate that tradition just so I could keep | |
611 track of what happens myself, not to mention some poor fool trying to | |
612 understand this years from now :-). | |
613 */ | |
614 | |
615 /* ********************************************************** Configuration */ | |
616 | |
617 #ifndef QSORT_ORDER_GUESS | |
618 #define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */ | |
619 #endif | |
620 | |
621 /* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for | |
622 future processing - a good max upper bound is log base 2 of memory size | |
623 (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can | |
624 safely be smaller than that since the program is taking up some space and | |
625 most operating systems only let you grab some subset of contiguous | |
626 memory (not to mention that you are normally sorting data larger than | |
627 1 byte element size :-). | |
628 */ | |
629 #ifndef QSORT_MAX_STACK | |
630 #define QSORT_MAX_STACK 32 | |
631 #endif | |
632 | |
633 /* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort. | |
634 Anything bigger and we use qsort. If you make this too small, the qsort | |
635 will probably break (or become less efficient), because it doesn't expect | |
636 the middle element of a partition to be the same as the right or left - | |
637 you have been warned). | |
638 */ | |
639 #ifndef QSORT_BREAK_EVEN | |
640 #define QSORT_BREAK_EVEN 6 | |
641 #endif | |
642 | |
643 /* QSORT_PLAY_SAFE is the size of the largest partition we're willing | |
644 to go quadratic on. We innoculate larger partitions against | |
645 quadratic behavior by shuffling them before sorting. This is not | |
646 an absolute guarantee of non-quadratic behavior, but it would take | |
647 staggeringly bad luck to pick extreme elements as the pivot | |
648 from randomized data. | |
649 */ | |
650 #ifndef QSORT_PLAY_SAFE | |
651 #define QSORT_PLAY_SAFE 255 | |
652 #endif | |
653 | |
654 /* ************************************************************* Data Types */ | |
655 | |
656 /* hold left and right index values of a partition waiting to be sorted (the | |
657 partition includes both left and right - right is NOT one past the end or | |
658 anything like that). | |
659 */ | |
660 struct partition_stack_entry { | |
661 int left; | |
662 int right; | |
663 #ifdef QSORT_ORDER_GUESS | |
664 int qsort_break_even; | |
665 #endif | |
666 }; | |
667 | |
668 /* ******************************************************* Shorthand Macros */ | |
669 | |
670 /* Note that these macros will be used from inside the qsort function where | |
671 we happen to know that the variable 'elt_size' contains the size of an | |
672 array element and the variable 'temp' points to enough space to hold a | |
673 temp element and the variable 'array' points to the array being sorted | |
674 and 'compare' is the pointer to the compare routine. | |
675 | |
676 Also note that there are very many highly architecture specific ways | |
677 these might be sped up, but this is simply the most generally portable | |
678 code I could think of. | |
679 */ | |
680 | |
681 /* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2 | |
682 */ | |
683 #define qsort_cmp(elt1, elt2) \ | |
684 ((*compare)(aTHX_ array[elt1], array[elt2])) | |
685 | |
686 #ifdef QSORT_ORDER_GUESS | |
687 #define QSORT_NOTICE_SWAP swapped++; | |
688 #else | |
689 #define QSORT_NOTICE_SWAP | |
690 #endif | |
691 | |
692 /* swaps contents of array elements elt1, elt2. | |
693 */ | |
694 #define qsort_swap(elt1, elt2) \ | |
695 STMT_START { \ | |
696 QSORT_NOTICE_SWAP \ | |
697 temp = array[elt1]; \ | |
698 array[elt1] = array[elt2]; \ | |
699 array[elt2] = temp; \ | |
700 } STMT_END | |
701 | |
702 /* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets | |
703 elt3 and elt3 gets elt1. | |
704 */ | |
705 #define qsort_rotate(elt1, elt2, elt3) \ | |
706 STMT_START { \ | |
707 QSORT_NOTICE_SWAP \ | |
708 temp = array[elt1]; \ | |
709 array[elt1] = array[elt2]; \ | |
710 array[elt2] = array[elt3]; \ | |
711 array[elt3] = temp; \ | |
712 } STMT_END | |
713 | |
714 /* ************************************************************ Debug stuff */ | |
715 | |
716 #ifdef QSORT_DEBUG | |
717 | |
718 static void | |
719 break_here() | |
720 { | |
721 return; /* good place to set a breakpoint */ | |
722 } | |
723 | |
724 #define qsort_assert(t) (void)( (t) || (break_here(), 0) ) | |
725 | |
726 static void | |
727 doqsort_all_asserts( | |
728 void * array, | |
729 size_t num_elts, | |
730 size_t elt_size, | |
731 int (*compare)(const void * elt1, const void * elt2), | |
732 int pc_left, int pc_right, int u_left, int u_right) | |
733 { | |
734 int i; | |
735 | |
736 qsort_assert(pc_left <= pc_right); | |
737 qsort_assert(u_right < pc_left); | |
738 qsort_assert(pc_right < u_left); | |
739 for (i = u_right + 1; i < pc_left; ++i) { | |
740 qsort_assert(qsort_cmp(i, pc_left) < 0); | |
741 } | |
742 for (i = pc_left; i < pc_right; ++i) { | |
743 qsort_assert(qsort_cmp(i, pc_right) == 0); | |
744 } | |
745 for (i = pc_right + 1; i < u_left; ++i) { | |
746 qsort_assert(qsort_cmp(pc_right, i) < 0); | |
747 } | |
748 } | |
749 | |
750 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \ | |
751 doqsort_all_asserts(array, num_elts, elt_size, compare, \ | |
752 PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) | |
753 | |
754 #else | |
755 | |
756 #define qsort_assert(t) ((void)0) | |
757 | |
758 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0) | |
759 | |
760 #endif | |
761 | |
762 /* ****************************************************************** qsort */ | |
763 | |
764 STATIC void /* the standard unstable (u) quicksort (qsort) */ | |
765 S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare) | |
766 { | |
767 SV * temp; | |
768 struct partition_stack_entry partition_stack[QSORT_MAX_STACK]; | |
769 int next_stack_entry = 0; | |
770 int part_left; | |
771 int part_right; | |
772 #ifdef QSORT_ORDER_GUESS | |
773 int qsort_break_even; | |
774 int swapped; | |
775 #endif | |
776 | |
777 PERL_ARGS_ASSERT_QSORTSVU; | |
778 | |
779 /* Make sure we actually have work to do. | |
780 */ | |
781 if (num_elts <= 1) { | |
782 return; | |
783 } | |
784 | |
785 /* Inoculate large partitions against quadratic behavior */ | |
786 if (num_elts > QSORT_PLAY_SAFE) { | |
787 size_t n; | |
788 SV ** const q = array; | |
789 for (n = num_elts; n > 1; ) { | |
790 const size_t j = (size_t)(n-- * Drand01()); | |
791 temp = q[j]; | |
792 q[j] = q[n]; | |
793 q[n] = temp; | |
794 } | |
795 } | |
796 | |
797 /* Setup the initial partition definition and fall into the sorting loop | |
798 */ | |
799 part_left = 0; | |
800 part_right = (int)(num_elts - 1); | |
801 #ifdef QSORT_ORDER_GUESS | |
802 qsort_break_even = QSORT_BREAK_EVEN; | |
803 #else | |
804 #define qsort_break_even QSORT_BREAK_EVEN | |
805 #endif | |
806 for ( ; ; ) { | |
807 if ((part_right - part_left) >= qsort_break_even) { | |
808 /* OK, this is gonna get hairy, so lets try to document all the | |
809 concepts and abbreviations and variables and what they keep | |
810 track of: | |
811 | |
812 pc: pivot chunk - the set of array elements we accumulate in the | |
813 middle of the partition, all equal in value to the original | |
814 pivot element selected. The pc is defined by: | |
815 | |
816 pc_left - the leftmost array index of the pc | |
817 pc_right - the rightmost array index of the pc | |
818 | |
819 we start with pc_left == pc_right and only one element | |
820 in the pivot chunk (but it can grow during the scan). | |
821 | |
822 u: uncompared elements - the set of elements in the partition | |
823 we have not yet compared to the pivot value. There are two | |
824 uncompared sets during the scan - one to the left of the pc | |
825 and one to the right. | |
826 | |
827 u_right - the rightmost index of the left side's uncompared set | |
828 u_left - the leftmost index of the right side's uncompared set | |
829 | |
830 The leftmost index of the left sides's uncompared set | |
831 doesn't need its own variable because it is always defined | |
832 by the leftmost edge of the whole partition (part_left). The | |
833 same goes for the rightmost edge of the right partition | |
834 (part_right). | |
835 | |
836 We know there are no uncompared elements on the left once we | |
837 get u_right < part_left and no uncompared elements on the | |
838 right once u_left > part_right. When both these conditions | |
839 are met, we have completed the scan of the partition. | |
840 | |
841 Any elements which are between the pivot chunk and the | |
842 uncompared elements should be less than the pivot value on | |
843 the left side and greater than the pivot value on the right | |
844 side (in fact, the goal of the whole algorithm is to arrange | |
845 for that to be true and make the groups of less-than and | |
846 greater-then elements into new partitions to sort again). | |
847 | |
848 As you marvel at the complexity of the code and wonder why it | |
849 has to be so confusing. Consider some of the things this level | |
850 of confusion brings: | |
851 | |
852 Once I do a compare, I squeeze every ounce of juice out of it. I | |
853 never do compare calls I don't have to do, and I certainly never | |
854 do redundant calls. | |
855 | |
856 I also never swap any elements unless I can prove there is a | |
857 good reason. Many sort algorithms will swap a known value with | |
858 an uncompared value just to get things in the right place (or | |
859 avoid complexity :-), but that uncompared value, once it gets | |
860 compared, may then have to be swapped again. A lot of the | |
861 complexity of this code is due to the fact that it never swaps | |
862 anything except compared values, and it only swaps them when the | |
863 compare shows they are out of position. | |
864 */ | |
865 int pc_left, pc_right; | |
866 int u_right, u_left; | |
867 | |
868 int s; | |
869 | |
870 pc_left = ((part_left + part_right) / 2); | |
871 pc_right = pc_left; | |
872 u_right = pc_left - 1; | |
873 u_left = pc_right + 1; | |
874 | |
875 /* Qsort works best when the pivot value is also the median value | |
876 in the partition (unfortunately you can't find the median value | |
877 without first sorting :-), so to give the algorithm a helping | |
878 hand, we pick 3 elements and sort them and use the median value | |
879 of that tiny set as the pivot value. | |
880 | |
881 Some versions of qsort like to use the left middle and right as | |
882 the 3 elements to sort so they can insure the ends of the | |
883 partition will contain values which will stop the scan in the | |
884 compare loop, but when you have to call an arbitrarily complex | |
885 routine to do a compare, its really better to just keep track of | |
886 array index values to know when you hit the edge of the | |
887 partition and avoid the extra compare. An even better reason to | |
888 avoid using a compare call is the fact that you can drop off the | |
889 edge of the array if someone foolishly provides you with an | |
890 unstable compare function that doesn't always provide consistent | |
891 results. | |
892 | |
893 So, since it is simpler for us to compare the three adjacent | |
894 elements in the middle of the partition, those are the ones we | |
895 pick here (conveniently pointed at by u_right, pc_left, and | |
896 u_left). The values of the left, center, and right elements | |
897 are referred to as l c and r in the following comments. | |
898 */ | |
899 | |
900 #ifdef QSORT_ORDER_GUESS | |
901 swapped = 0; | |
902 #endif | |
903 s = qsort_cmp(u_right, pc_left); | |
904 if (s < 0) { | |
905 /* l < c */ | |
906 s = qsort_cmp(pc_left, u_left); | |
907 /* if l < c, c < r - already in order - nothing to do */ | |
908 if (s == 0) { | |
909 /* l < c, c == r - already in order, pc grows */ | |
910 ++pc_right; | |
911 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
912 } else if (s > 0) { | |
913 /* l < c, c > r - need to know more */ | |
914 s = qsort_cmp(u_right, u_left); | |
915 if (s < 0) { | |
916 /* l < c, c > r, l < r - swap c & r to get ordered */ | |
917 qsort_swap(pc_left, u_left); | |
918 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
919 } else if (s == 0) { | |
920 /* l < c, c > r, l == r - swap c&r, grow pc */ | |
921 qsort_swap(pc_left, u_left); | |
922 --pc_left; | |
923 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
924 } else { | |
925 /* l < c, c > r, l > r - make lcr into rlc to get ordered */ | |
926 qsort_rotate(pc_left, u_right, u_left); | |
927 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
928 } | |
929 } | |
930 } else if (s == 0) { | |
931 /* l == c */ | |
932 s = qsort_cmp(pc_left, u_left); | |
933 if (s < 0) { | |
934 /* l == c, c < r - already in order, grow pc */ | |
935 --pc_left; | |
936 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
937 } else if (s == 0) { | |
938 /* l == c, c == r - already in order, grow pc both ways */ | |
939 --pc_left; | |
940 ++pc_right; | |
941 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
942 } else { | |
943 /* l == c, c > r - swap l & r, grow pc */ | |
944 qsort_swap(u_right, u_left); | |
945 ++pc_right; | |
946 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
947 } | |
948 } else { | |
949 /* l > c */ | |
950 s = qsort_cmp(pc_left, u_left); | |
951 if (s < 0) { | |
952 /* l > c, c < r - need to know more */ | |
953 s = qsort_cmp(u_right, u_left); | |
954 if (s < 0) { | |
955 /* l > c, c < r, l < r - swap l & c to get ordered */ | |
956 qsort_swap(u_right, pc_left); | |
957 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
958 } else if (s == 0) { | |
959 /* l > c, c < r, l == r - swap l & c, grow pc */ | |
960 qsort_swap(u_right, pc_left); | |
961 ++pc_right; | |
962 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
963 } else { | |
964 /* l > c, c < r, l > r - rotate lcr into crl to order */ | |
965 qsort_rotate(u_right, pc_left, u_left); | |
966 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
967 } | |
968 } else if (s == 0) { | |
969 /* l > c, c == r - swap ends, grow pc */ | |
970 qsort_swap(u_right, u_left); | |
971 --pc_left; | |
972 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
973 } else { | |
974 /* l > c, c > r - swap ends to get in order */ | |
975 qsort_swap(u_right, u_left); | |
976 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); | |
977 } | |
978 } | |
979 /* We now know the 3 middle elements have been compared and | |
980 arranged in the desired order, so we can shrink the uncompared | |
981 sets on both sides | |
982 */ | |
983 --u_right; | |
984 ++u_left; | |
985 qsort_all_asserts(pc_left, pc_right, u_left, u_right); | |
986 | |
987 /* The above massive nested if was the simple part :-). We now have | |
988 the middle 3 elements ordered and we need to scan through the | |
989 uncompared sets on either side, swapping elements that are on | |
990 the wrong side or simply shuffling equal elements around to get | |
991 all equal elements into the pivot chunk. | |
992 */ | |
993 | |
994 for ( ; ; ) { | |
995 int still_work_on_left; | |
996 int still_work_on_right; | |
997 | |
998 /* Scan the uncompared values on the left. If I find a value | |
999 equal to the pivot value, move it over so it is adjacent to | |
1000 the pivot chunk and expand the pivot chunk. If I find a value | |
1001 less than the pivot value, then just leave it - its already | |
1002 on the correct side of the partition. If I find a greater | |
1003 value, then stop the scan. | |
1004 */ | |
1005 while ((still_work_on_left = (u_right >= part_left))) { | |
1006 s = qsort_cmp(u_right, pc_left); | |
1007 if (s < 0) { | |
1008 --u_right; | |
1009 } else if (s == 0) { | |
1010 --pc_left; | |
1011 if (pc_left != u_right) { | |
1012 qsort_swap(u_right, pc_left); | |
1013 } | |
1014 --u_right; | |
1015 } else { | |
1016 break; | |
1017 } | |
1018 qsort_assert(u_right < pc_left); | |
1019 qsort_assert(pc_left <= pc_right); | |
1020 qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0); | |
1021 qsort_assert(qsort_cmp(pc_left, pc_right) == 0); | |
1022 } | |
1023 | |
1024 /* Do a mirror image scan of uncompared values on the right | |
1025 */ | |
1026 while ((still_work_on_right = (u_left <= part_right))) { | |
1027 s = qsort_cmp(pc_right, u_left); | |
1028 if (s < 0) { | |
1029 ++u_left; | |
1030 } else if (s == 0) { | |
1031 ++pc_right; | |
1032 if (pc_right != u_left) { | |
1033 qsort_swap(pc_right, u_left); | |
1034 } | |
1035 ++u_left; | |
1036 } else { | |
1037 break; | |
1038 } | |
1039 qsort_assert(u_left > pc_right); | |
1040 qsort_assert(pc_left <= pc_right); | |
1041 qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0); | |
1042 qsort_assert(qsort_cmp(pc_left, pc_right) == 0); | |
1043 } | |
1044 | |
1045 if (still_work_on_left) { | |
1046 /* I know I have a value on the left side which needs to be | |
1047 on the right side, but I need to know more to decide | |
1048 exactly the best thing to do with it. | |
1049 */ | |
1050 if (still_work_on_right) { | |
1051 /* I know I have values on both side which are out of | |
1052 position. This is a big win because I kill two birds | |
1053 with one swap (so to speak). I can advance the | |
1054 uncompared pointers on both sides after swapping both | |
1055 of them into the right place. | |
1056 */ | |
1057 qsort_swap(u_right, u_left); | |
1058 --u_right; | |
1059 ++u_left; | |
1060 qsort_all_asserts(pc_left, pc_right, u_left, u_right); | |
1061 } else { | |
1062 /* I have an out of position value on the left, but the | |
1063 right is fully scanned, so I "slide" the pivot chunk | |
1064 and any less-than values left one to make room for the | |
1065 greater value over on the right. If the out of position | |
1066 value is immediately adjacent to the pivot chunk (there | |
1067 are no less-than values), I can do that with a swap, | |
1068 otherwise, I have to rotate one of the less than values | |
1069 into the former position of the out of position value | |
1070 and the right end of the pivot chunk into the left end | |
1071 (got all that?). | |
1072 */ | |
1073 --pc_left; | |
1074 if (pc_left == u_right) { | |
1075 qsort_swap(u_right, pc_right); | |
1076 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); | |
1077 } else { | |
1078 qsort_rotate(u_right, pc_left, pc_right); | |
1079 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); | |
1080 } | |
1081 --pc_right; | |
1082 --u_right; | |
1083 } | |
1084 } else if (still_work_on_right) { | |
1085 /* Mirror image of complex case above: I have an out of | |
1086 position value on the right, but the left is fully | |
1087 scanned, so I need to shuffle things around to make room | |
1088 for the right value on the left. | |
1089 */ | |
1090 ++pc_right; | |
1091 if (pc_right == u_left) { | |
1092 qsort_swap(u_left, pc_left); | |
1093 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); | |
1094 } else { | |
1095 qsort_rotate(pc_right, pc_left, u_left); | |
1096 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); | |
1097 } | |
1098 ++pc_left; | |
1099 ++u_left; | |
1100 } else { | |
1101 /* No more scanning required on either side of partition, | |
1102 break out of loop and figure out next set of partitions | |
1103 */ | |
1104 break; | |
1105 } | |
1106 } | |
1107 | |
1108 /* The elements in the pivot chunk are now in the right place. They | |
1109 will never move or be compared again. All I have to do is decide | |
1110 what to do with the stuff to the left and right of the pivot | |
1111 chunk. | |
1112 | |
1113 Notes on the QSORT_ORDER_GUESS ifdef code: | |
1114 | |
1115 1. If I just built these partitions without swapping any (or | |
1116 very many) elements, there is a chance that the elements are | |
1117 already ordered properly (being properly ordered will | |
1118 certainly result in no swapping, but the converse can't be | |
1119 proved :-). | |
1120 | |
1121 2. A (properly written) insertion sort will run faster on | |
1122 already ordered data than qsort will. | |
1123 | |
1124 3. Perhaps there is some way to make a good guess about | |
1125 switching to an insertion sort earlier than partition size 6 | |
1126 (for instance - we could save the partition size on the stack | |
1127 and increase the size each time we find we didn't swap, thus | |
1128 switching to insertion sort earlier for partitions with a | |
1129 history of not swapping). | |
1130 | |
1131 4. Naturally, if I just switch right away, it will make | |
1132 artificial benchmarks with pure ascending (or descending) | |
1133 data look really good, but is that a good reason in general? | |
1134 Hard to say... | |
1135 */ | |
1136 | |
1137 #ifdef QSORT_ORDER_GUESS | |
1138 if (swapped < 3) { | |
1139 #if QSORT_ORDER_GUESS == 1 | |
1140 qsort_break_even = (part_right - part_left) + 1; | |
1141 #endif | |
1142 #if QSORT_ORDER_GUESS == 2 | |
1143 qsort_break_even *= 2; | |
1144 #endif | |
1145 #if QSORT_ORDER_GUESS == 3 | |
1146 const int prev_break = qsort_break_even; | |
1147 qsort_break_even *= qsort_break_even; | |
1148 if (qsort_break_even < prev_break) { | |
1149 qsort_break_even = (part_right - part_left) + 1; | |
1150 } | |
1151 #endif | |
1152 } else { | |
1153 qsort_break_even = QSORT_BREAK_EVEN; | |
1154 } | |
1155 #endif | |
1156 | |
1157 if (part_left < pc_left) { | |
1158 /* There are elements on the left which need more processing. | |
1159 Check the right as well before deciding what to do. | |
1160 */ | |
1161 if (pc_right < part_right) { | |
1162 /* We have two partitions to be sorted. Stack the biggest one | |
1163 and process the smallest one on the next iteration. This | |
1164 minimizes the stack height by insuring that any additional | |
1165 stack entries must come from the smallest partition which | |
1166 (because it is smallest) will have the fewest | |
1167 opportunities to generate additional stack entries. | |
1168 */ | |
1169 if ((part_right - pc_right) > (pc_left - part_left)) { | |
1170 /* stack the right partition, process the left */ | |
1171 partition_stack[next_stack_entry].left = pc_right + 1; | |
1172 partition_stack[next_stack_entry].right = part_right; | |
1173 #ifdef QSORT_ORDER_GUESS | |
1174 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; | |
1175 #endif | |
1176 part_right = pc_left - 1; | |
1177 } else { | |
1178 /* stack the left partition, process the right */ | |
1179 partition_stack[next_stack_entry].left = part_left; | |
1180 partition_stack[next_stack_entry].right = pc_left - 1; | |
1181 #ifdef QSORT_ORDER_GUESS | |
1182 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; | |
1183 #endif | |
1184 part_left = pc_right + 1; | |
1185 } | |
1186 qsort_assert(next_stack_entry < QSORT_MAX_STACK); | |
1187 ++next_stack_entry; | |
1188 } else { | |
1189 /* The elements on the left are the only remaining elements | |
1190 that need sorting, arrange for them to be processed as the | |
1191 next partition. | |
1192 */ | |
1193 part_right = pc_left - 1; | |
1194 } | |
1195 } else if (pc_right < part_right) { | |
1196 /* There is only one chunk on the right to be sorted, make it | |
1197 the new partition and loop back around. | |
1198 */ | |
1199 part_left = pc_right + 1; | |
1200 } else { | |
1201 /* This whole partition wound up in the pivot chunk, so | |
1202 we need to get a new partition off the stack. | |
1203 */ | |
1204 if (next_stack_entry == 0) { | |
1205 /* the stack is empty - we are done */ | |
1206 break; | |
1207 } | |
1208 --next_stack_entry; | |
1209 part_left = partition_stack[next_stack_entry].left; | |
1210 part_right = partition_stack[next_stack_entry].right; | |
1211 #ifdef QSORT_ORDER_GUESS | |
1212 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; | |
1213 #endif | |
1214 } | |
1215 } else { | |
1216 /* This partition is too small to fool with qsort complexity, just | |
1217 do an ordinary insertion sort to minimize overhead. | |
1218 */ | |
1219 int i; | |
1220 /* Assume 1st element is in right place already, and start checking | |
1221 at 2nd element to see where it should be inserted. | |
1222 */ | |
1223 for (i = part_left + 1; i <= part_right; ++i) { | |
1224 int j; | |
1225 /* Scan (backwards - just in case 'i' is already in right place) | |
1226 through the elements already sorted to see if the ith element | |
1227 belongs ahead of one of them. | |
1228 */ | |
1229 for (j = i - 1; j >= part_left; --j) { | |
1230 if (qsort_cmp(i, j) >= 0) { | |
1231 /* i belongs right after j | |
1232 */ | |
1233 break; | |
1234 } | |
1235 } | |
1236 ++j; | |
1237 if (j != i) { | |
1238 /* Looks like we really need to move some things | |
1239 */ | |
1240 int k; | |
1241 temp = array[i]; | |
1242 for (k = i - 1; k >= j; --k) | |
1243 array[k + 1] = array[k]; | |
1244 array[j] = temp; | |
1245 } | |
1246 } | |
1247 | |
1248 /* That partition is now sorted, grab the next one, or get out | |
1249 of the loop if there aren't any more. | |
1250 */ | |
1251 | |
1252 if (next_stack_entry == 0) { | |
1253 /* the stack is empty - we are done */ | |
1254 break; | |
1255 } | |
1256 --next_stack_entry; | |
1257 part_left = partition_stack[next_stack_entry].left; | |
1258 part_right = partition_stack[next_stack_entry].right; | |
1259 #ifdef QSORT_ORDER_GUESS | |
1260 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; | |
1261 #endif | |
1262 } | |
1263 } | |
1264 | |
1265 /* Believe it or not, the array is sorted at this point! */ | |
1266 } | |
1267 | |
1268 /* Stabilize what is, presumably, an otherwise unstable sort method. | |
1269 * We do that by allocating (or having on hand) an array of pointers | |
1270 * that is the same size as the original array of elements to be sorted. | |
1271 * We initialize this parallel array with the addresses of the original | |
1272 * array elements. This indirection can make you crazy. | |
1273 * Some pictures can help. After initializing, we have | |
1274 * | |
1275 * indir list1 | |
1276 * +----+ +----+ | |
1277 * | | --------------> | | ------> first element to be sorted | |
1278 * +----+ +----+ | |
1279 * | | --------------> | | ------> second element to be sorted | |
1280 * +----+ +----+ | |
1281 * | | --------------> | | ------> third element to be sorted | |
1282 * +----+ +----+ | |
1283 * ... | |
1284 * +----+ +----+ | |
1285 * | | --------------> | | ------> n-1st element to be sorted | |
1286 * +----+ +----+ | |
1287 * | | --------------> | | ------> n-th element to be sorted | |
1288 * +----+ +----+ | |
1289 * | |
1290 * During the sort phase, we leave the elements of list1 where they are, | |
1291 * and sort the pointers in the indirect array in the same order determined | |
1292 * by the original comparison routine on the elements pointed to. | |
1293 * Because we don't move the elements of list1 around through | |
1294 * this phase, we can break ties on elements that compare equal | |
1295 * using their address in the list1 array, ensuring stability. | |
1296 * This leaves us with something looking like | |
1297 * | |
1298 * indir list1 | |
1299 * +----+ +----+ | |
1300 * | | --+ +---> | | ------> first element to be sorted | |
1301 * +----+ | | +----+ | |
1302 * | | --|-------|---> | | ------> second element to be sorted | |
1303 * +----+ | | +----+ | |
1304 * | | --|-------+ +-> | | ------> third element to be sorted | |
1305 * +----+ | | +----+ | |
1306 * ... | |
1307 * +----+ | | | | +----+ | |
1308 * | | ---|-+ | +--> | | ------> n-1st element to be sorted | |
1309 * +----+ | | +----+ | |
1310 * | | ---+ +----> | | ------> n-th element to be sorted | |
1311 * +----+ +----+ | |
1312 * | |
1313 * where the i-th element of the indirect array points to the element | |
1314 * that should be i-th in the sorted array. After the sort phase, | |
1315 * we have to put the elements of list1 into the places | |
1316 * dictated by the indirect array. | |
1317 */ | |
1318 | |
1319 | |
1320 static I32 | |
1321 cmpindir(pTHX_ gptr const a, gptr const b) | |
1322 { | |
1323 gptr * const ap = (gptr *)a; | |
1324 gptr * const bp = (gptr *)b; | |
1325 const I32 sense = PL_sort_RealCmp(aTHX_ *ap, *bp); | |
1326 | |
1327 if (sense) | |
1328 return sense; | |
1329 return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0); | |
1330 } | |
1331 | |
1332 static I32 | |
1333 cmpindir_desc(pTHX_ gptr const a, gptr const b) | |
1334 { | |
1335 gptr * const ap = (gptr *)a; | |
1336 gptr * const bp = (gptr *)b; | |
1337 const I32 sense = PL_sort_RealCmp(aTHX_ *ap, *bp); | |
1338 | |
1339 /* Reverse the default */ | |
1340 if (sense) | |
1341 return -sense; | |
1342 /* But don't reverse the stability test. */ | |
1343 return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0); | |
1344 | |
1345 } | |
1346 | |
1347 STATIC void | |
1348 S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp, U32 flags) | |
1349 { | |
1350 if ((flags & SORTf_STABLE) != 0) { | |
1351 gptr **pp, *q; | |
1352 size_t n, j, i; | |
1353 gptr *small[SMALLSORT], **indir, tmp; | |
1354 SVCOMPARE_t savecmp; | |
1355 if (nmemb <= 1) return; /* sorted trivially */ | |
1356 | |
1357 /* Small arrays can use the stack, big ones must be allocated */ | |
1358 if (nmemb <= SMALLSORT) indir = small; | |
1359 else { Newx(indir, nmemb, gptr *); } | |
1360 | |
1361 /* Copy pointers to original array elements into indirect array */ | |
1362 for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++; | |
1363 | |
1364 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ | |
1365 PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */ | |
1366 | |
1367 /* sort, with indirection */ | |
1368 if (flags & SORTf_DESC) | |
1369 qsortsvu((gptr *)indir, nmemb, cmpindir_desc); | |
1370 else | |
1371 qsortsvu((gptr *)indir, nmemb, cmpindir); | |
1372 | |
1373 pp = indir; | |
1374 q = list1; | |
1375 for (n = nmemb; n--; ) { | |
1376 /* Assert A: all elements of q with index > n are already | |
1377 * in place. This is vacuously true at the start, and we | |
1378 * put element n where it belongs below (if it wasn't | |
1379 * already where it belonged). Assert B: we only move | |
1380 * elements that aren't where they belong, | |
1381 * so, by A, we never tamper with elements above n. | |
1382 */ | |
1383 j = pp[n] - q; /* This sets j so that q[j] is | |
1384 * at pp[n]. *pp[j] belongs in | |
1385 * q[j], by construction. | |
1386 */ | |
1387 if (n != j) { /* all's well if n == j */ | |
1388 tmp = q[j]; /* save what's in q[j] */ | |
1389 do { | |
1390 q[j] = *pp[j]; /* put *pp[j] where it belongs */ | |
1391 i = pp[j] - q; /* the index in q of the element | |
1392 * just moved */ | |
1393 pp[j] = q + j; /* this is ok now */ | |
1394 } while ((j = i) != n); | |
1395 /* There are only finitely many (nmemb) addresses | |
1396 * in the pp array. | |
1397 * So we must eventually revisit an index we saw before. | |
1398 * Suppose the first revisited index is k != n. | |
1399 * An index is visited because something else belongs there. | |
1400 * If we visit k twice, then two different elements must | |
1401 * belong in the same place, which cannot be. | |
1402 * So j must get back to n, the loop terminates, | |
1403 * and we put the saved element where it belongs. | |
1404 */ | |
1405 q[n] = tmp; /* put what belongs into | |
1406 * the n-th element */ | |
1407 } | |
1408 } | |
1409 | |
1410 /* free iff allocated */ | |
1411 if (indir != small) { Safefree(indir); } | |
1412 /* restore prevailing comparison routine */ | |
1413 PL_sort_RealCmp = savecmp; | |
1414 } else if ((flags & SORTf_DESC) != 0) { | |
1415 const SVCOMPARE_t savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ | |
1416 PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */ | |
1417 cmp = cmp_desc; | |
1418 qsortsvu(list1, nmemb, cmp); | |
1419 /* restore prevailing comparison routine */ | |
1420 PL_sort_RealCmp = savecmp; | |
1421 } else { | |
1422 qsortsvu(list1, nmemb, cmp); | |
1423 } | |
1424 } | |
1425 | |
1426 /* | |
1427 =head1 Array Manipulation Functions | |
1428 | |
1429 =for apidoc sortsv | |
1430 | |
1431 Sort an array. Here is an example: | |
1432 | |
1433 sortsv(AvARRAY(av), av_top_index(av)+1, Perl_sv_cmp_locale); | |
1434 | |
1435 Currently this always uses mergesort. See sortsv_flags for a more | |
1436 flexible routine. | |
1437 | |
1438 =cut | |
1439 */ | |
1440 | |
1441 void | |
1442 Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) | |
1443 { | |
1444 PERL_ARGS_ASSERT_SORTSV; | |
1445 | |
1446 sortsv_flags(array, nmemb, cmp, 0); | |
1447 } | |
1448 | |
1449 /* | |
1450 =for apidoc sortsv_flags | |
1451 | |
1452 Sort an array, with various options. | |
1453 | |
1454 =cut | |
1455 */ | |
1456 void | |
1457 Perl_sortsv_flags(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags) | |
1458 { | |
1459 PERL_ARGS_ASSERT_SORTSV_FLAGS; | |
1460 | |
1461 if (flags & SORTf_QSORT) | |
1462 S_qsortsv(aTHX_ array, nmemb, cmp, flags); | |
1463 else | |
1464 S_mergesortsv(aTHX_ array, nmemb, cmp, flags); | |
1465 } | |
1466 | |
1467 #define SvNSIOK(sv) ((SvFLAGS(sv) & SVf_NOK) || ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK)) | |
1468 #define SvSIOK(sv) ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK) | |
1469 #define SvNSIV(sv) ( SvNOK(sv) ? SvNVX(sv) : ( SvSIOK(sv) ? SvIVX(sv) : sv_2nv(sv) ) ) | |
1470 | |
1471 PP(pp_sort) | |
1472 { | |
1473 dSP; dMARK; dORIGMARK; | |
1474 SV **p1 = ORIGMARK+1, **p2; | |
1475 SSize_t max, i; | |
1476 AV* av = NULL; | |
1477 GV *gv; | |
1478 CV *cv = NULL; | |
1479 I32 gimme = GIMME_V; | |
1480 OP* const nextop = PL_op->op_next; | |
1481 I32 overloading = 0; | |
1482 bool hasargs = FALSE; | |
1483 bool copytmps; | |
1484 I32 is_xsub = 0; | |
1485 I32 sorting_av = 0; | |
1486 const U8 priv = PL_op->op_private; | |
1487 const U8 flags = PL_op->op_flags; | |
1488 U32 sort_flags = 0; | |
1489 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags) | |
1490 = Perl_sortsv_flags; | |
1491 I32 all_SIVs = 1; | |
1492 | |
1493 if ((priv & OPpSORT_DESCEND) != 0) | |
1494 sort_flags |= SORTf_DESC; | |
1495 if ((priv & OPpSORT_QSORT) != 0) | |
1496 sort_flags |= SORTf_QSORT; | |
1497 if ((priv & OPpSORT_STABLE) != 0) | |
1498 sort_flags |= SORTf_STABLE; | |
1499 | |
1500 if (gimme != G_ARRAY) { | |
1501 SP = MARK; | |
1502 EXTEND(SP,1); | |
1503 RETPUSHUNDEF; | |
1504 } | |
1505 | |
1506 ENTER; | |
1507 SAVEVPTR(PL_sortcop); | |
1508 if (flags & OPf_STACKED) { | |
1509 if (flags & OPf_SPECIAL) { | |
1510 OP *nullop = OpSIBLING(cLISTOP->op_first); /* pass pushmark */ | |
1511 assert(nullop->op_type == OP_NULL); | |
1512 PL_sortcop = nullop->op_next; | |
1513 } | |
1514 else { | |
1515 GV *autogv = NULL; | |
1516 HV *stash; | |
1517 cv = sv_2cv(*++MARK, &stash, &gv, GV_ADD); | |
1518 check_cv: | |
1519 if (cv && SvPOK(cv)) { | |
1520 const char * const proto = SvPV_nolen_const(MUTABLE_SV(cv)); | |
1521 if (proto && strEQ(proto, "$$")) { | |
1522 hasargs = TRUE; | |
1523 } | |
1524 } | |
1525 if (cv && CvISXSUB(cv) && CvXSUB(cv)) { | |
1526 is_xsub = 1; | |
1527 } | |
1528 else if (!(cv && CvROOT(cv))) { | |
1529 if (gv) { | |
1530 goto autoload; | |
1531 } | |
1532 else if (!CvANON(cv) && (gv = CvGV(cv))) { | |
1533 if (cv != GvCV(gv)) cv = GvCV(gv); | |
1534 autoload: | |
1535 if (!autogv && ( | |
1536 autogv = gv_autoload_pvn( | |
1537 GvSTASH(gv), GvNAME(gv), GvNAMELEN(gv), | |
1538 GvNAMEUTF8(gv) ? SVf_UTF8 : 0 | |
1539 ) | |
1540 )) { | |
1541 cv = GvCVu(autogv); | |
1542 goto check_cv; | |
1543 } | |
1544 else { | |
1545 SV *tmpstr = sv_newmortal(); | |
1546 gv_efullname3(tmpstr, gv, NULL); | |
1547 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called", | |
1548 SVfARG(tmpstr)); | |
1549 } | |
1550 } | |
1551 else { | |
1552 DIE(aTHX_ "Undefined subroutine in sort"); | |
1553 } | |
1554 } | |
1555 | |
1556 if (is_xsub) | |
1557 PL_sortcop = (OP*)cv; | |
1558 else | |
1559 PL_sortcop = CvSTART(cv); | |
1560 } | |
1561 } | |
1562 else { | |
1563 PL_sortcop = NULL; | |
1564 } | |
1565 | |
1566 /* optimiser converts "@a = sort @a" to "sort \@a"; | |
1567 * in case of tied @a, pessimise: push (@a) onto stack, then assign | |
1568 * result back to @a at the end of this function */ | |
1569 if (priv & OPpSORT_INPLACE) { | |
1570 assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV); | |
1571 (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */ | |
1572 av = MUTABLE_AV((*SP)); | |
1573 max = AvFILL(av) + 1; | |
1574 if (SvMAGICAL(av)) { | |
1575 MEXTEND(SP, max); | |
1576 for (i=0; i < max; i++) { | |
1577 SV **svp = av_fetch(av, i, FALSE); | |
1578 *SP++ = (svp) ? *svp : NULL; | |
1579 } | |
1580 SP--; | |
1581 p1 = p2 = SP - (max-1); | |
1582 } | |
1583 else { | |
1584 if (SvREADONLY(av)) | |
1585 Perl_croak_no_modify(); | |
1586 else | |
1587 { | |
1588 SvREADONLY_on(av); | |
1589 save_pushptr((void *)av, SAVEt_READONLY_OFF); | |
1590 } | |
1591 p1 = p2 = AvARRAY(av); | |
1592 sorting_av = 1; | |
1593 } | |
1594 } | |
1595 else { | |
1596 p2 = MARK+1; | |
1597 max = SP - MARK; | |
1598 } | |
1599 | |
1600 /* shuffle stack down, removing optional initial cv (p1!=p2), plus | |
1601 * any nulls; also stringify or converting to integer or number as | |
1602 * required any args */ | |
1603 copytmps = !sorting_av && PL_sortcop; | |
1604 for (i=max; i > 0 ; i--) { | |
1605 if ((*p1 = *p2++)) { /* Weed out nulls. */ | |
1606 if (copytmps && SvPADTMP(*p1)) { | |
1607 *p1 = sv_mortalcopy(*p1); | |
1608 } | |
1609 SvTEMP_off(*p1); | |
1610 if (!PL_sortcop) { | |
1611 if (priv & OPpSORT_NUMERIC) { | |
1612 if (priv & OPpSORT_INTEGER) { | |
1613 if (!SvIOK(*p1)) | |
1614 (void)sv_2iv_flags(*p1, SV_GMAGIC|SV_SKIP_OVERLOAD); | |
1615 } | |
1616 else { | |
1617 if (!SvNSIOK(*p1)) | |
1618 (void)sv_2nv_flags(*p1, SV_GMAGIC|SV_SKIP_OVERLOAD); | |
1619 if (all_SIVs && !SvSIOK(*p1)) | |
1620 all_SIVs = 0; | |
1621 } | |
1622 } | |
1623 else { | |
1624 if (!SvPOK(*p1)) | |
1625 (void)sv_2pv_flags(*p1, 0, | |
1626 SV_GMAGIC|SV_CONST_RETURN|SV_SKIP_OVERLOAD); | |
1627 } | |
1628 if (SvAMAGIC(*p1)) | |
1629 overloading = 1; | |
1630 } | |
1631 p1++; | |
1632 } | |
1633 else | |
1634 max--; | |
1635 } | |
1636 if (sorting_av) | |
1637 AvFILLp(av) = max-1; | |
1638 | |
1639 if (max > 1) { | |
1640 SV **start; | |
1641 if (PL_sortcop) { | |
1642 PERL_CONTEXT *cx; | |
1643 SV** newsp; | |
1644 const bool oldcatch = CATCH_GET; | |
1645 | |
1646 SAVETMPS; | |
1647 SAVEOP(); | |
1648 | |
1649 CATCH_SET(TRUE); | |
1650 PUSHSTACKi(PERLSI_SORT); | |
1651 if (!hasargs && !is_xsub) { | |
1652 SAVEGENERICSV(PL_firstgv); | |
1653 SAVEGENERICSV(PL_secondgv); | |
1654 PL_firstgv = MUTABLE_GV(SvREFCNT_inc( | |
1655 gv_fetchpvs("a", GV_ADD|GV_NOTQUAL, SVt_PV) | |
1656 )); | |
1657 PL_secondgv = MUTABLE_GV(SvREFCNT_inc( | |
1658 gv_fetchpvs("b", GV_ADD|GV_NOTQUAL, SVt_PV) | |
1659 )); | |
1660 SAVESPTR(GvSV(PL_firstgv)); | |
1661 SAVESPTR(GvSV(PL_secondgv)); | |
1662 } | |
1663 | |
1664 PUSHBLOCK(cx, CXt_NULL, PL_stack_base); | |
1665 if (!(flags & OPf_SPECIAL)) { | |
1666 cx->cx_type = CXt_SUB; | |
1667 cx->blk_gimme = G_SCALAR; | |
1668 /* If our comparison routine is already active (CvDEPTH is | |
1669 * is not 0), then PUSHSUB does not increase the refcount, | |
1670 * so we have to do it ourselves, because the LEAVESUB fur- | |
1671 * ther down lowers it. */ | |
1672 if (CvDEPTH(cv)) SvREFCNT_inc_simple_void_NN(cv); | |
1673 PUSHSUB(cx); | |
1674 if (!is_xsub) { | |
1675 PADLIST * const padlist = CvPADLIST(cv); | |
1676 | |
1677 if (++CvDEPTH(cv) >= 2) { | |
1678 PERL_STACK_OVERFLOW_CHECK(); | |
1679 pad_push(padlist, CvDEPTH(cv)); | |
1680 } | |
1681 SAVECOMPPAD(); | |
1682 PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv)); | |
1683 | |
1684 if (hasargs) { | |
1685 /* This is mostly copied from pp_entersub */ | |
1686 AV * const av = MUTABLE_AV(PAD_SVl(0)); | |
1687 | |
1688 cx->blk_sub.savearray = GvAV(PL_defgv); | |
1689 GvAV(PL_defgv) = MUTABLE_AV(SvREFCNT_inc_simple(av)); | |
1690 CX_CURPAD_SAVE(cx->blk_sub); | |
1691 cx->blk_sub.argarray = av; | |
1692 } | |
1693 | |
1694 } | |
1695 } | |
1696 cx->cx_type |= CXp_MULTICALL; | |
1697 | |
1698 start = p1 - max; | |
1699 sortsvp(aTHX_ start, max, | |
1700 (is_xsub ? S_sortcv_xsub : hasargs ? S_sortcv_stacked : S_sortcv), | |
1701 sort_flags); | |
1702 | |
1703 if (!(flags & OPf_SPECIAL)) { | |
1704 SV *sv; | |
1705 /* Reset cx, in case the context stack has been | |
1706 reallocated. */ | |
1707 cx = &cxstack[cxstack_ix]; | |
1708 POPSUB(cx, sv); | |
1709 LEAVESUB(sv); | |
1710 } | |
1711 POPBLOCK(cx,PL_curpm); | |
1712 PL_stack_sp = newsp; | |
1713 POPSTACK; | |
1714 CATCH_SET(oldcatch); | |
1715 } | |
1716 else { | |
1717 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */ | |
1718 start = sorting_av ? AvARRAY(av) : ORIGMARK+1; | |
1719 sortsvp(aTHX_ start, max, | |
1720 (priv & OPpSORT_NUMERIC) | |
1721 ? ( ( ( priv & OPpSORT_INTEGER) || all_SIVs) | |
1722 ? ( overloading ? S_amagic_i_ncmp : S_sv_i_ncmp) | |
1723 : ( overloading ? S_amagic_ncmp : S_sv_ncmp ) ) | |
1724 : ( | |
1725 #ifdef USE_LOCALE_COLLATE | |
1726 IN_LC_RUNTIME(LC_COLLATE) | |
1727 ? ( overloading | |
1728 ? (SVCOMPARE_t)S_amagic_cmp_locale | |
1729 : (SVCOMPARE_t)sv_cmp_locale_static) | |
1730 : | |
1731 #endif | |
1732 ( overloading ? (SVCOMPARE_t)S_amagic_cmp : (SVCOMPARE_t)sv_cmp_static)), | |
1733 sort_flags); | |
1734 } | |
1735 if ((priv & OPpSORT_REVERSE) != 0) { | |
1736 SV **q = start+max-1; | |
1737 while (start < q) { | |
1738 SV * const tmp = *start; | |
1739 *start++ = *q; | |
1740 *q-- = tmp; | |
1741 } | |
1742 } | |
1743 } | |
1744 if (sorting_av) | |
1745 SvREADONLY_off(av); | |
1746 else if (av && !sorting_av) { | |
1747 /* simulate pp_aassign of tied AV */ | |
1748 SV** const base = MARK+1; | |
1749 for (i=0; i < max; i++) { | |
1750 base[i] = newSVsv(base[i]); | |
1751 } | |
1752 av_clear(av); | |
1753 av_extend(av, max); | |
1754 for (i=0; i < max; i++) { | |
1755 SV * const sv = base[i]; | |
1756 SV ** const didstore = av_store(av, i, sv); | |
1757 if (SvSMAGICAL(sv)) | |
1758 mg_set(sv); | |
1759 if (!didstore) | |
1760 sv_2mortal(sv); | |
1761 } | |
1762 } | |
1763 LEAVE; | |
1764 PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max); | |
1765 return nextop; | |
1766 } | |
1767 | |
1768 static I32 | |
1769 S_sortcv(pTHX_ SV *const a, SV *const b) | |
1770 { | |
1771 const I32 oldsaveix = PL_savestack_ix; | |
1772 const I32 oldscopeix = PL_scopestack_ix; | |
1773 I32 result; | |
1774 SV *resultsv; | |
1775 PMOP * const pm = PL_curpm; | |
1776 OP * const sortop = PL_op; | |
1777 COP * const cop = PL_curcop; | |
1778 | |
1779 PERL_ARGS_ASSERT_SORTCV; | |
1780 | |
1781 GvSV(PL_firstgv) = a; | |
1782 GvSV(PL_secondgv) = b; | |
1783 PL_stack_sp = PL_stack_base; | |
1784 PL_op = PL_sortcop; | |
1785 CALLRUNOPS(aTHX); | |
1786 PL_op = sortop; | |
1787 PL_curcop = cop; | |
1788 if (PL_stack_sp != PL_stack_base + 1) { | |
1789 assert(PL_stack_sp == PL_stack_base); | |
1790 resultsv = &PL_sv_undef; | |
1791 } | |
1792 else resultsv = *PL_stack_sp; | |
1793 if (SvNIOK_nog(resultsv)) result = SvIV(resultsv); | |
1794 else { | |
1795 ENTER; | |
1796 SAVEVPTR(PL_curpad); | |
1797 PL_curpad = 0; | |
1798 result = SvIV(resultsv); | |
1799 LEAVE; | |
1800 } | |
1801 while (PL_scopestack_ix > oldscopeix) { | |
1802 LEAVE; | |
1803 } | |
1804 leave_scope(oldsaveix); | |
1805 PL_curpm = pm; | |
1806 return result; | |
1807 } | |
1808 | |
1809 static I32 | |
1810 S_sortcv_stacked(pTHX_ SV *const a, SV *const b) | |
1811 { | |
1812 const I32 oldsaveix = PL_savestack_ix; | |
1813 const I32 oldscopeix = PL_scopestack_ix; | |
1814 I32 result; | |
1815 AV * const av = GvAV(PL_defgv); | |
1816 PMOP * const pm = PL_curpm; | |
1817 OP * const sortop = PL_op; | |
1818 COP * const cop = PL_curcop; | |
1819 SV **pad; | |
1820 | |
1821 PERL_ARGS_ASSERT_SORTCV_STACKED; | |
1822 | |
1823 if (AvREAL(av)) { | |
1824 av_clear(av); | |
1825 AvREAL_off(av); | |
1826 AvREIFY_on(av); | |
1827 } | |
1828 if (AvMAX(av) < 1) { | |
1829 SV **ary = AvALLOC(av); | |
1830 if (AvARRAY(av) != ary) { | |
1831 AvMAX(av) += AvARRAY(av) - AvALLOC(av); | |
1832 AvARRAY(av) = ary; | |
1833 } | |
1834 if (AvMAX(av) < 1) { | |
1835 AvMAX(av) = 1; | |
1836 Renew(ary,2,SV*); | |
1837 AvARRAY(av) = ary; | |
1838 AvALLOC(av) = ary; | |
1839 } | |
1840 } | |
1841 AvFILLp(av) = 1; | |
1842 | |
1843 AvARRAY(av)[0] = a; | |
1844 AvARRAY(av)[1] = b; | |
1845 PL_stack_sp = PL_stack_base; | |
1846 PL_op = PL_sortcop; | |
1847 CALLRUNOPS(aTHX); | |
1848 PL_op = sortop; | |
1849 PL_curcop = cop; | |
1850 pad = PL_curpad; PL_curpad = 0; | |
1851 if (PL_stack_sp != PL_stack_base + 1) { | |
1852 assert(PL_stack_sp == PL_stack_base); | |
1853 result = SvIV(&PL_sv_undef); | |
1854 } | |
1855 else result = SvIV(*PL_stack_sp); | |
1856 PL_curpad = pad; | |
1857 while (PL_scopestack_ix > oldscopeix) { | |
1858 LEAVE; | |
1859 } | |
1860 leave_scope(oldsaveix); | |
1861 PL_curpm = pm; | |
1862 return result; | |
1863 } | |
1864 | |
1865 static I32 | |
1866 S_sortcv_xsub(pTHX_ SV *const a, SV *const b) | |
1867 { | |
1868 dSP; | |
1869 const I32 oldsaveix = PL_savestack_ix; | |
1870 const I32 oldscopeix = PL_scopestack_ix; | |
1871 CV * const cv=MUTABLE_CV(PL_sortcop); | |
1872 I32 result; | |
1873 PMOP * const pm = PL_curpm; | |
1874 | |
1875 PERL_ARGS_ASSERT_SORTCV_XSUB; | |
1876 | |
1877 SP = PL_stack_base; | |
1878 PUSHMARK(SP); | |
1879 EXTEND(SP, 2); | |
1880 *++SP = a; | |
1881 *++SP = b; | |
1882 PUTBACK; | |
1883 (void)(*CvXSUB(cv))(aTHX_ cv); | |
1884 if (PL_stack_sp != PL_stack_base + 1) | |
1885 Perl_croak(aTHX_ "Sort subroutine didn't return single value"); | |
1886 result = SvIV(*PL_stack_sp); | |
1887 while (PL_scopestack_ix > oldscopeix) { | |
1888 LEAVE; | |
1889 } | |
1890 leave_scope(oldsaveix); | |
1891 PL_curpm = pm; | |
1892 return result; | |
1893 } | |
1894 | |
1895 | |
1896 static I32 | |
1897 S_sv_ncmp(pTHX_ SV *const a, SV *const b) | |
1898 { | |
1899 const NV nv1 = SvNSIV(a); | |
1900 const NV nv2 = SvNSIV(b); | |
1901 | |
1902 PERL_ARGS_ASSERT_SV_NCMP; | |
1903 | |
1904 #if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan) | |
1905 if (Perl_isnan(nv1) || Perl_isnan(nv2)) { | |
1906 #else | |
1907 if (nv1 != nv1 || nv2 != nv2) { | |
1908 #endif | |
1909 if (ckWARN(WARN_UNINITIALIZED)) report_uninit(NULL); | |
1910 return 0; | |
1911 } | |
1912 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0; | |
1913 } | |
1914 | |
1915 static I32 | |
1916 S_sv_i_ncmp(pTHX_ SV *const a, SV *const b) | |
1917 { | |
1918 const IV iv1 = SvIV(a); | |
1919 const IV iv2 = SvIV(b); | |
1920 | |
1921 PERL_ARGS_ASSERT_SV_I_NCMP; | |
1922 | |
1923 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0; | |
1924 } | |
1925 | |
1926 #define tryCALL_AMAGICbin(left,right,meth) \ | |
1927 (SvAMAGIC(left)||SvAMAGIC(right)) \ | |
1928 ? amagic_call(left, right, meth, 0) \ | |
1929 : NULL; | |
1930 | |
1931 #define SORT_NORMAL_RETURN_VALUE(val) (((val) > 0) ? 1 : ((val) ? -1 : 0)) | |
1932 | |
1933 static I32 | |
1934 S_amagic_ncmp(pTHX_ SV *const a, SV *const b) | |
1935 { | |
1936 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp_amg); | |
1937 | |
1938 PERL_ARGS_ASSERT_AMAGIC_NCMP; | |
1939 | |
1940 if (tmpsv) { | |
1941 if (SvIOK(tmpsv)) { | |
1942 const I32 i = SvIVX(tmpsv); | |
1943 return SORT_NORMAL_RETURN_VALUE(i); | |
1944 } | |
1945 else { | |
1946 const NV d = SvNV(tmpsv); | |
1947 return SORT_NORMAL_RETURN_VALUE(d); | |
1948 } | |
1949 } | |
1950 return S_sv_ncmp(aTHX_ a, b); | |
1951 } | |
1952 | |
1953 static I32 | |
1954 S_amagic_i_ncmp(pTHX_ SV *const a, SV *const b) | |
1955 { | |
1956 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp_amg); | |
1957 | |
1958 PERL_ARGS_ASSERT_AMAGIC_I_NCMP; | |
1959 | |
1960 if (tmpsv) { | |
1961 if (SvIOK(tmpsv)) { | |
1962 const I32 i = SvIVX(tmpsv); | |
1963 return SORT_NORMAL_RETURN_VALUE(i); | |
1964 } | |
1965 else { | |
1966 const NV d = SvNV(tmpsv); | |
1967 return SORT_NORMAL_RETURN_VALUE(d); | |
1968 } | |
1969 } | |
1970 return S_sv_i_ncmp(aTHX_ a, b); | |
1971 } | |
1972 | |
1973 static I32 | |
1974 S_amagic_cmp(pTHX_ SV *const str1, SV *const str2) | |
1975 { | |
1976 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp_amg); | |
1977 | |
1978 PERL_ARGS_ASSERT_AMAGIC_CMP; | |
1979 | |
1980 if (tmpsv) { | |
1981 if (SvIOK(tmpsv)) { | |
1982 const I32 i = SvIVX(tmpsv); | |
1983 return SORT_NORMAL_RETURN_VALUE(i); | |
1984 } | |
1985 else { | |
1986 const NV d = SvNV(tmpsv); | |
1987 return SORT_NORMAL_RETURN_VALUE(d); | |
1988 } | |
1989 } | |
1990 return sv_cmp(str1, str2); | |
1991 } | |
1992 | |
1993 #ifdef USE_LOCALE_COLLATE | |
1994 | |
1995 static I32 | |
1996 S_amagic_cmp_locale(pTHX_ SV *const str1, SV *const str2) | |
1997 { | |
1998 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp_amg); | |
1999 | |
2000 PERL_ARGS_ASSERT_AMAGIC_CMP_LOCALE; | |
2001 | |
2002 if (tmpsv) { | |
2003 if (SvIOK(tmpsv)) { | |
2004 const I32 i = SvIVX(tmpsv); | |
2005 return SORT_NORMAL_RETURN_VALUE(i); | |
2006 } | |
2007 else { | |
2008 const NV d = SvNV(tmpsv); | |
2009 return SORT_NORMAL_RETURN_VALUE(d); | |
2010 } | |
2011 } | |
2012 return sv_cmp_locale(str1, str2); | |
2013 } | |
2014 | |
2015 #endif | |
2016 | |
2017 /* | |
2018 * ex: set ts=8 sts=4 sw=4 et: | |
2019 */ |