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Re: [perl #36350] unstable sorting for use integer; sort { $b <=> $a } @foo
[perl5.git] / pp_sort.c
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1/* pp_sort.c
2 *
4bb101f2 3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
241d1a3b 4 * 2000, 2001, 2002, 2003, 2004, 2005, by Larry Wall and others
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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
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16/* This file contains pp ("push/pop") functions that
17 * execute the opcodes that make up a perl program. A typical pp function
18 * expects to find its arguments on the stack, and usually pushes its
19 * results onto the stack, hence the 'pp' terminology. Each OP structure
20 * contains a pointer to the relevant pp_foo() function.
21 *
22 * This particular file just contains pp_sort(), which is complex
23 * enough to merit its own file! See the other pp*.c files for the rest of
24 * the pp_ functions.
25 */
26
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27#include "EXTERN.h"
28#define PERL_IN_PP_SORT_C
29#include "perl.h"
30
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31#if defined(UNDER_CE)
32/* looks like 'small' is reserved word for WINCE (or somesuch)*/
33#define small xsmall
34#endif
35
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36static I32 sortcv(pTHX_ SV *a, SV *b);
37static I32 sortcv_stacked(pTHX_ SV *a, SV *b);
38static I32 sortcv_xsub(pTHX_ SV *a, SV *b);
39static I32 sv_ncmp(pTHX_ SV *a, SV *b);
40static I32 sv_i_ncmp(pTHX_ SV *a, SV *b);
41static I32 amagic_ncmp(pTHX_ SV *a, SV *b);
42static I32 amagic_i_ncmp(pTHX_ SV *a, SV *b);
43static I32 amagic_cmp(pTHX_ SV *a, SV *b);
44static I32 amagic_cmp_locale(pTHX_ SV *a, SV *b);
45
46#define sv_cmp_static Perl_sv_cmp
47#define sv_cmp_locale_static Perl_sv_cmp_locale
48
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49#define dSORTHINTS SV *hintsv = GvSV(gv_fetchpv("sort::hints", GV_ADDMULTI, SVt_IV))
50#define SORTHINTS (SvIOK(hintsv) ? ((I32)SvIV(hintsv)) : 0)
84d4ea48 51
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52#ifndef SMALLSORT
53#define SMALLSORT (200)
54#endif
55
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56/*
57 * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>.
58 *
59 * The original code was written in conjunction with BSD Computer Software
60 * Research Group at University of California, Berkeley.
61 *
62 * See also: "Optimistic Merge Sort" (SODA '92)
63 *
64 * The integration to Perl is by John P. Linderman <jpl@research.att.com>.
65 *
66 * The code can be distributed under the same terms as Perl itself.
67 *
68 */
69
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70
71typedef char * aptr; /* pointer for arithmetic on sizes */
72typedef SV * gptr; /* pointers in our lists */
73
74/* Binary merge internal sort, with a few special mods
75** for the special perl environment it now finds itself in.
76**
77** Things that were once options have been hotwired
78** to values suitable for this use. In particular, we'll always
79** initialize looking for natural runs, we'll always produce stable
80** output, and we'll always do Peter McIlroy's binary merge.
81*/
82
83/* Pointer types for arithmetic and storage and convenience casts */
84
85#define APTR(P) ((aptr)(P))
86#define GPTP(P) ((gptr *)(P))
87#define GPPP(P) ((gptr **)(P))
88
89
90/* byte offset from pointer P to (larger) pointer Q */
91#define BYTEOFF(P, Q) (APTR(Q) - APTR(P))
92
93#define PSIZE sizeof(gptr)
94
95/* If PSIZE is power of 2, make PSHIFT that power, if that helps */
96
97#ifdef PSHIFT
98#define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT))
99#define PNBYTE(N) ((N) << (PSHIFT))
100#define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N)))
101#else
102/* Leave optimization to compiler */
103#define PNELEM(P, Q) (GPTP(Q) - GPTP(P))
104#define PNBYTE(N) ((N) * (PSIZE))
105#define PINDEX(P, N) (GPTP(P) + (N))
106#endif
107
108/* Pointer into other corresponding to pointer into this */
109#define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P))
110
111#define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim)
112
113
114/* Runs are identified by a pointer in the auxilliary list.
115** The pointer is at the start of the list,
116** and it points to the start of the next list.
117** NEXT is used as an lvalue, too.
118*/
119
120#define NEXT(P) (*GPPP(P))
121
122
123/* PTHRESH is the minimum number of pairs with the same sense to justify
124** checking for a run and extending it. Note that PTHRESH counts PAIRS,
125** not just elements, so PTHRESH == 8 means a run of 16.
126*/
127
128#define PTHRESH (8)
129
130/* RTHRESH is the number of elements in a run that must compare low
131** to the low element from the opposing run before we justify
132** doing a binary rampup instead of single stepping.
133** In random input, N in a row low should only happen with
134** probability 2^(1-N), so we can risk that we are dealing
135** with orderly input without paying much when we aren't.
136*/
137
138#define RTHRESH (6)
139
140
141/*
142** Overview of algorithm and variables.
143** The array of elements at list1 will be organized into runs of length 2,
144** or runs of length >= 2 * PTHRESH. We only try to form long runs when
145** PTHRESH adjacent pairs compare in the same way, suggesting overall order.
146**
147** Unless otherwise specified, pair pointers address the first of two elements.
148**
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149** b and b+1 are a pair that compare with sense "sense".
150** b is the "bottom" of adjacent pairs that might form a longer run.
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151**
152** p2 parallels b in the list2 array, where runs are defined by
153** a pointer chain.
154**
a0288114 155** t represents the "top" of the adjacent pairs that might extend
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156** the run beginning at b. Usually, t addresses a pair
157** that compares with opposite sense from (b,b+1).
158** However, it may also address a singleton element at the end of list1,
a0288114 159** or it may be equal to "last", the first element beyond list1.
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160**
161** r addresses the Nth pair following b. If this would be beyond t,
162** we back it off to t. Only when r is less than t do we consider the
163** run long enough to consider checking.
164**
165** q addresses a pair such that the pairs at b through q already form a run.
166** Often, q will equal b, indicating we only are sure of the pair itself.
167** However, a search on the previous cycle may have revealed a longer run,
168** so q may be greater than b.
169**
170** p is used to work back from a candidate r, trying to reach q,
171** which would mean b through r would be a run. If we discover such a run,
172** we start q at r and try to push it further towards t.
173** If b through r is NOT a run, we detect the wrong order at (p-1,p).
174** In any event, after the check (if any), we have two main cases.
175**
176** 1) Short run. b <= q < p <= r <= t.
177** b through q is a run (perhaps trivial)
178** q through p are uninteresting pairs
179** p through r is a run
180**
181** 2) Long run. b < r <= q < t.
182** b through q is a run (of length >= 2 * PTHRESH)
183**
184** Note that degenerate cases are not only possible, but likely.
185** For example, if the pair following b compares with opposite sense,
186** then b == q < p == r == t.
187*/
188
189
957d8989 190static IV
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191dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, SVCOMPARE_t cmp)
192{
957d8989 193 I32 sense;
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194 register gptr *b, *p, *q, *t, *p2;
195 register gptr c, *last, *r;
196 gptr *savep;
957d8989 197 IV runs = 0;
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198
199 b = list1;
200 last = PINDEX(b, nmemb);
201 sense = (cmp(aTHX_ *b, *(b+1)) > 0);
202 for (p2 = list2; b < last; ) {
203 /* We just started, or just reversed sense.
204 ** Set t at end of pairs with the prevailing sense.
205 */
206 for (p = b+2, t = p; ++p < last; t = ++p) {
207 if ((cmp(aTHX_ *t, *p) > 0) != sense) break;
208 }
209 q = b;
210 /* Having laid out the playing field, look for long runs */
211 do {
212 p = r = b + (2 * PTHRESH);
213 if (r >= t) p = r = t; /* too short to care about */
214 else {
215 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) &&
216 ((p -= 2) > q));
217 if (p <= q) {
218 /* b through r is a (long) run.
219 ** Extend it as far as possible.
220 */
221 p = q = r;
222 while (((p += 2) < t) &&
223 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p;
224 r = p = q + 2; /* no simple pairs, no after-run */
225 }
226 }
227 if (q > b) { /* run of greater than 2 at b */
228 savep = p;
229 p = q += 2;
230 /* pick up singleton, if possible */
231 if ((p == t) &&
232 ((t + 1) == last) &&
233 ((cmp(aTHX_ *(p-1), *p) > 0) == sense))
234 savep = r = p = q = last;
957d8989 235 p2 = NEXT(p2) = p2 + (p - b); ++runs;
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236 if (sense) while (b < --p) {
237 c = *b;
238 *b++ = *p;
239 *p = c;
240 }
241 p = savep;
242 }
243 while (q < p) { /* simple pairs */
957d8989 244 p2 = NEXT(p2) = p2 + 2; ++runs;
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245 if (sense) {
246 c = *q++;
247 *(q-1) = *q;
248 *q++ = c;
249 } else q += 2;
250 }
251 if (((b = p) == t) && ((t+1) == last)) {
957d8989 252 NEXT(p2) = p2 + 1; ++runs;
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253 b++;
254 }
255 q = r;
256 } while (b < t);
257 sense = !sense;
258 }
957d8989 259 return runs;
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260}
261
262
3fe0b9a9 263/* The original merge sort, in use since 5.7, was as fast as, or faster than,
957d8989 264 * qsort on many platforms, but slower than qsort, conspicuously so,
3fe0b9a9 265 * on others. The most likely explanation was platform-specific
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266 * differences in cache sizes and relative speeds.
267 *
268 * The quicksort divide-and-conquer algorithm guarantees that, as the
269 * problem is subdivided into smaller and smaller parts, the parts
270 * fit into smaller (and faster) caches. So it doesn't matter how
271 * many levels of cache exist, quicksort will "find" them, and,
272 * as long as smaller is faster, take advanatge of them.
273 *
3fe0b9a9 274 * By contrast, consider how the original mergesort algorithm worked.
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275 * Suppose we have five runs (each typically of length 2 after dynprep).
276 *
277 * pass base aux
278 * 0 1 2 3 4 5
279 * 1 12 34 5
280 * 2 1234 5
281 * 3 12345
282 * 4 12345
283 *
284 * Adjacent pairs are merged in "grand sweeps" through the input.
285 * This means, on pass 1, the records in runs 1 and 2 aren't revisited until
286 * runs 3 and 4 are merged and the runs from run 5 have been copied.
287 * The only cache that matters is one large enough to hold *all* the input.
288 * On some platforms, this may be many times slower than smaller caches.
289 *
290 * The following pseudo-code uses the same basic merge algorithm,
291 * but in a divide-and-conquer way.
292 *
293 * # merge $runs runs at offset $offset of list $list1 into $list2.
294 * # all unmerged runs ($runs == 1) originate in list $base.
295 * sub mgsort2 {
296 * my ($offset, $runs, $base, $list1, $list2) = @_;
297 *
298 * if ($runs == 1) {
299 * if ($list1 is $base) copy run to $list2
300 * return offset of end of list (or copy)
301 * } else {
302 * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1)
303 * mgsort2($off2, $runs/2, $base, $list2, $list1)
304 * merge the adjacent runs at $offset of $list1 into $list2
305 * return the offset of the end of the merged runs
306 * }
307 * }
308 * mgsort2(0, $runs, $base, $aux, $base);
309 *
310 * For our 5 runs, the tree of calls looks like
311 *
312 * 5
313 * 3 2
314 * 2 1 1 1
315 * 1 1
316 *
317 * 1 2 3 4 5
318 *
319 * and the corresponding activity looks like
320 *
321 * copy runs 1 and 2 from base to aux
322 * merge runs 1 and 2 from aux to base
323 * (run 3 is where it belongs, no copy needed)
324 * merge runs 12 and 3 from base to aux
325 * (runs 4 and 5 are where they belong, no copy needed)
326 * merge runs 4 and 5 from base to aux
327 * merge runs 123 and 45 from aux to base
328 *
329 * Note that we merge runs 1 and 2 immediately after copying them,
330 * while they are still likely to be in fast cache. Similarly,
331 * run 3 is merged with run 12 while it still may be lingering in cache.
332 * This implementation should therefore enjoy much of the cache-friendly
333 * behavior that quicksort does. In addition, it does less copying
334 * than the original mergesort implementation (only runs 1 and 2 are copied)
335 * and the "balancing" of merges is better (merged runs comprise more nearly
336 * equal numbers of original runs).
337 *
338 * The actual cache-friendly implementation will use a pseudo-stack
339 * to avoid recursion, and will unroll processing of runs of length 2,
340 * but it is otherwise similar to the recursive implementation.
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341 */
342
343typedef struct {
344 IV offset; /* offset of 1st of 2 runs at this level */
345 IV runs; /* how many runs must be combined into 1 */
346} off_runs; /* pseudo-stack element */
347
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348
349static I32
350cmp_desc(pTHX_ gptr a, gptr b)
351{
352 return -PL_sort_RealCmp(aTHX_ a, b);
353}
354
957d8989 355STATIC void
6c3fb703 356S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
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357{
358 IV i, run, runs, offset;
359 I32 sense, level;
360 int iwhich;
361 register gptr *f1, *f2, *t, *b, *p, *tp2, *l1, *l2, *q;
362 gptr *aux, *list1, *list2;
363 gptr *p1;
364 gptr small[SMALLSORT];
365 gptr *which[3];
366 off_runs stack[60], *stackp;
a80036c6 367 SVCOMPARE_t savecmp = 0;
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368
369 if (nmemb <= 1) return; /* sorted trivially */
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370
371 if (flags) {
372 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
373 PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */
374 cmp = cmp_desc;
375 }
376
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377 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */
378 else { New(799,aux,nmemb,gptr); } /* allocate auxilliary array */
379 level = 0;
380 stackp = stack;
381 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp);
382 stackp->offset = offset = 0;
383 which[0] = which[2] = base;
384 which[1] = aux;
385 for (;;) {
386 /* On levels where both runs have be constructed (stackp->runs == 0),
387 * merge them, and note the offset of their end, in case the offset
388 * is needed at the next level up. Hop up a level, and,
389 * as long as stackp->runs is 0, keep merging.
390 */
391 if ((runs = stackp->runs) == 0) {
392 iwhich = level & 1;
393 list1 = which[iwhich]; /* area where runs are now */
394 list2 = which[++iwhich]; /* area for merged runs */
395 do {
396 offset = stackp->offset;
397 f1 = p1 = list1 + offset; /* start of first run */
398 p = tp2 = list2 + offset; /* where merged run will go */
399 t = NEXT(p); /* where first run ends */
400 f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */
401 t = NEXT(t); /* where second runs ends */
402 l2 = POTHER(t, list2, list1); /* ... on the other side */
403 offset = PNELEM(list2, t);
404 while (f1 < l1 && f2 < l2) {
405 /* If head 1 is larger than head 2, find ALL the elements
406 ** in list 2 strictly less than head1, write them all,
407 ** then head 1. Then compare the new heads, and repeat,
408 ** until one or both lists are exhausted.
409 **
410 ** In all comparisons (after establishing
411 ** which head to merge) the item to merge
412 ** (at pointer q) is the first operand of
413 ** the comparison. When we want to know
a0288114 414 ** if "q is strictly less than the other",
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415 ** we can't just do
416 ** cmp(q, other) < 0
417 ** because stability demands that we treat equality
418 ** as high when q comes from l2, and as low when
419 ** q was from l1. So we ask the question by doing
420 ** cmp(q, other) <= sense
421 ** and make sense == 0 when equality should look low,
422 ** and -1 when equality should look high.
423 */
424
425
426 if (cmp(aTHX_ *f1, *f2) <= 0) {
427 q = f2; b = f1; t = l1;
428 sense = -1;
429 } else {
430 q = f1; b = f2; t = l2;
431 sense = 0;
432 }
433
434
435 /* ramp up
436 **
437 ** Leave t at something strictly
438 ** greater than q (or at the end of the list),
439 ** and b at something strictly less than q.
440 */
441 for (i = 1, run = 0 ;;) {
442 if ((p = PINDEX(b, i)) >= t) {
443 /* off the end */
444 if (((p = PINDEX(t, -1)) > b) &&
445 (cmp(aTHX_ *q, *p) <= sense))
446 t = p;
447 else b = p;
448 break;
449 } else if (cmp(aTHX_ *q, *p) <= sense) {
450 t = p;
451 break;
452 } else b = p;
453 if (++run >= RTHRESH) i += i;
454 }
455
456
457 /* q is known to follow b and must be inserted before t.
458 ** Increment b, so the range of possibilities is [b,t).
459 ** Round binary split down, to favor early appearance.
460 ** Adjust b and t until q belongs just before t.
461 */
462
463 b++;
464 while (b < t) {
465 p = PINDEX(b, (PNELEM(b, t) - 1) / 2);
466 if (cmp(aTHX_ *q, *p) <= sense) {
467 t = p;
468 } else b = p + 1;
469 }
470
471
472 /* Copy all the strictly low elements */
473
474 if (q == f1) {
475 FROMTOUPTO(f2, tp2, t);
476 *tp2++ = *f1++;
477 } else {
478 FROMTOUPTO(f1, tp2, t);
479 *tp2++ = *f2++;
480 }
481 }
482
483
484 /* Run out remaining list */
485 if (f1 == l1) {
486 if (f2 < l2) FROMTOUPTO(f2, tp2, l2);
487 } else FROMTOUPTO(f1, tp2, l1);
488 p1 = NEXT(p1) = POTHER(tp2, list2, list1);
489
490 if (--level == 0) goto done;
491 --stackp;
492 t = list1; list1 = list2; list2 = t; /* swap lists */
493 } while ((runs = stackp->runs) == 0);
494 }
495
496
497 stackp->runs = 0; /* current run will finish level */
498 /* While there are more than 2 runs remaining,
499 * turn them into exactly 2 runs (at the "other" level),
500 * each made up of approximately half the runs.
501 * Stack the second half for later processing,
502 * and set about producing the first half now.
503 */
504 while (runs > 2) {
505 ++level;
506 ++stackp;
507 stackp->offset = offset;
508 runs -= stackp->runs = runs / 2;
509 }
510 /* We must construct a single run from 1 or 2 runs.
511 * All the original runs are in which[0] == base.
512 * The run we construct must end up in which[level&1].
513 */
514 iwhich = level & 1;
515 if (runs == 1) {
516 /* Constructing a single run from a single run.
517 * If it's where it belongs already, there's nothing to do.
518 * Otherwise, copy it to where it belongs.
519 * A run of 1 is either a singleton at level 0,
520 * or the second half of a split 3. In neither event
521 * is it necessary to set offset. It will be set by the merge
522 * that immediately follows.
523 */
524 if (iwhich) { /* Belongs in aux, currently in base */
525 f1 = b = PINDEX(base, offset); /* where list starts */
526 f2 = PINDEX(aux, offset); /* where list goes */
527 t = NEXT(f2); /* where list will end */
528 offset = PNELEM(aux, t); /* offset thereof */
529 t = PINDEX(base, offset); /* where it currently ends */
530 FROMTOUPTO(f1, f2, t); /* copy */
531 NEXT(b) = t; /* set up parallel pointer */
532 } else if (level == 0) goto done; /* single run at level 0 */
533 } else {
534 /* Constructing a single run from two runs.
535 * The merge code at the top will do that.
536 * We need only make sure the two runs are in the "other" array,
537 * so they'll end up in the correct array after the merge.
538 */
539 ++level;
540 ++stackp;
541 stackp->offset = offset;
542 stackp->runs = 0; /* take care of both runs, trigger merge */
543 if (!iwhich) { /* Merged runs belong in aux, copy 1st */
544 f1 = b = PINDEX(base, offset); /* where first run starts */
545 f2 = PINDEX(aux, offset); /* where it will be copied */
546 t = NEXT(f2); /* where first run will end */
547 offset = PNELEM(aux, t); /* offset thereof */
548 p = PINDEX(base, offset); /* end of first run */
549 t = NEXT(t); /* where second run will end */
550 t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */
551 FROMTOUPTO(f1, f2, t); /* copy both runs */
552 NEXT(b) = p; /* paralled pointer for 1st */
553 NEXT(p) = t; /* ... and for second */
554 }
555 }
556 }
557done:
558 if (aux != small) Safefree(aux); /* free iff allocated */
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559 if (flags) {
560 PL_sort_RealCmp = savecmp; /* Restore current comparison routine, if any */
561 }
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562 return;
563}
564
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565/*
566 * The quicksort implementation was derived from source code contributed
567 * by Tom Horsley.
568 *
569 * NOTE: this code was derived from Tom Horsley's qsort replacement
570 * and should not be confused with the original code.
571 */
572
573/* Copyright (C) Tom Horsley, 1997. All rights reserved.
574
575 Permission granted to distribute under the same terms as perl which are
576 (briefly):
577
578 This program is free software; you can redistribute it and/or modify
579 it under the terms of either:
580
581 a) the GNU General Public License as published by the Free
582 Software Foundation; either version 1, or (at your option) any
583 later version, or
584
585 b) the "Artistic License" which comes with this Kit.
586
587 Details on the perl license can be found in the perl source code which
588 may be located via the www.perl.com web page.
589
590 This is the most wonderfulest possible qsort I can come up with (and
591 still be mostly portable) My (limited) tests indicate it consistently
592 does about 20% fewer calls to compare than does the qsort in the Visual
593 C++ library, other vendors may vary.
594
595 Some of the ideas in here can be found in "Algorithms" by Sedgewick,
596 others I invented myself (or more likely re-invented since they seemed
597 pretty obvious once I watched the algorithm operate for a while).
598
599 Most of this code was written while watching the Marlins sweep the Giants
600 in the 1997 National League Playoffs - no Braves fans allowed to use this
601 code (just kidding :-).
602
603 I realize that if I wanted to be true to the perl tradition, the only
604 comment in this file would be something like:
605
606 ...they shuffled back towards the rear of the line. 'No, not at the
607 rear!' the slave-driver shouted. 'Three files up. And stay there...
608
609 However, I really needed to violate that tradition just so I could keep
610 track of what happens myself, not to mention some poor fool trying to
611 understand this years from now :-).
612*/
613
614/* ********************************************************** Configuration */
615
616#ifndef QSORT_ORDER_GUESS
617#define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */
618#endif
619
620/* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for
621 future processing - a good max upper bound is log base 2 of memory size
622 (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can
623 safely be smaller than that since the program is taking up some space and
624 most operating systems only let you grab some subset of contiguous
625 memory (not to mention that you are normally sorting data larger than
626 1 byte element size :-).
627*/
628#ifndef QSORT_MAX_STACK
629#define QSORT_MAX_STACK 32
630#endif
631
632/* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort.
633 Anything bigger and we use qsort. If you make this too small, the qsort
634 will probably break (or become less efficient), because it doesn't expect
635 the middle element of a partition to be the same as the right or left -
636 you have been warned).
637*/
638#ifndef QSORT_BREAK_EVEN
639#define QSORT_BREAK_EVEN 6
640#endif
641
4eb872f6
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642/* QSORT_PLAY_SAFE is the size of the largest partition we're willing
643 to go quadratic on. We innoculate larger partitions against
644 quadratic behavior by shuffling them before sorting. This is not
645 an absolute guarantee of non-quadratic behavior, but it would take
646 staggeringly bad luck to pick extreme elements as the pivot
647 from randomized data.
648*/
649#ifndef QSORT_PLAY_SAFE
650#define QSORT_PLAY_SAFE 255
651#endif
652
84d4ea48
JH
653/* ************************************************************* Data Types */
654
655/* hold left and right index values of a partition waiting to be sorted (the
656 partition includes both left and right - right is NOT one past the end or
657 anything like that).
658*/
659struct partition_stack_entry {
660 int left;
661 int right;
662#ifdef QSORT_ORDER_GUESS
663 int qsort_break_even;
664#endif
665};
666
667/* ******************************************************* Shorthand Macros */
668
669/* Note that these macros will be used from inside the qsort function where
670 we happen to know that the variable 'elt_size' contains the size of an
671 array element and the variable 'temp' points to enough space to hold a
672 temp element and the variable 'array' points to the array being sorted
673 and 'compare' is the pointer to the compare routine.
674
675 Also note that there are very many highly architecture specific ways
676 these might be sped up, but this is simply the most generally portable
677 code I could think of.
678*/
679
680/* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2
681*/
682#define qsort_cmp(elt1, elt2) \
683 ((*compare)(aTHX_ array[elt1], array[elt2]))
684
685#ifdef QSORT_ORDER_GUESS
686#define QSORT_NOTICE_SWAP swapped++;
687#else
688#define QSORT_NOTICE_SWAP
689#endif
690
691/* swaps contents of array elements elt1, elt2.
692*/
693#define qsort_swap(elt1, elt2) \
694 STMT_START { \
695 QSORT_NOTICE_SWAP \
696 temp = array[elt1]; \
697 array[elt1] = array[elt2]; \
698 array[elt2] = temp; \
699 } STMT_END
700
701/* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets
702 elt3 and elt3 gets elt1.
703*/
704#define qsort_rotate(elt1, elt2, elt3) \
705 STMT_START { \
706 QSORT_NOTICE_SWAP \
707 temp = array[elt1]; \
708 array[elt1] = array[elt2]; \
709 array[elt2] = array[elt3]; \
710 array[elt3] = temp; \
711 } STMT_END
712
713/* ************************************************************ Debug stuff */
714
715#ifdef QSORT_DEBUG
716
717static void
718break_here()
719{
720 return; /* good place to set a breakpoint */
721}
722
723#define qsort_assert(t) (void)( (t) || (break_here(), 0) )
724
725static void
726doqsort_all_asserts(
727 void * array,
728 size_t num_elts,
729 size_t elt_size,
730 int (*compare)(const void * elt1, const void * elt2),
731 int pc_left, int pc_right, int u_left, int u_right)
732{
733 int i;
734
735 qsort_assert(pc_left <= pc_right);
736 qsort_assert(u_right < pc_left);
737 qsort_assert(pc_right < u_left);
738 for (i = u_right + 1; i < pc_left; ++i) {
739 qsort_assert(qsort_cmp(i, pc_left) < 0);
740 }
741 for (i = pc_left; i < pc_right; ++i) {
742 qsort_assert(qsort_cmp(i, pc_right) == 0);
743 }
744 for (i = pc_right + 1; i < u_left; ++i) {
745 qsort_assert(qsort_cmp(pc_right, i) < 0);
746 }
747}
748
749#define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \
750 doqsort_all_asserts(array, num_elts, elt_size, compare, \
751 PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT)
752
753#else
754
755#define qsort_assert(t) ((void)0)
756
757#define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0)
758
759#endif
760
761/* ****************************************************************** qsort */
762
763STATIC void /* the standard unstable (u) quicksort (qsort) */
764S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare)
765{
766 register SV * temp;
767
768 struct partition_stack_entry partition_stack[QSORT_MAX_STACK];
769 int next_stack_entry = 0;
770
771 int part_left;
772 int part_right;
773#ifdef QSORT_ORDER_GUESS
774 int qsort_break_even;
775 int swapped;
776#endif
777
778 /* Make sure we actually have work to do.
779 */
780 if (num_elts <= 1) {
781 return;
782 }
783
4eb872f6
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784 /* Innoculate large partitions against quadratic behavior */
785 if (num_elts > QSORT_PLAY_SAFE) {
901017d6
AL
786 register size_t n;
787 register SV ** const q = array;
788 for (n = num_elts; n > 1; ) {
789 register const size_t j = (size_t)(n-- * Drand01());
4eb872f6
JL
790 temp = q[j];
791 q[j] = q[n];
792 q[n] = temp;
793 }
794 }
795
84d4ea48
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796 /* Setup the initial partition definition and fall into the sorting loop
797 */
798 part_left = 0;
799 part_right = (int)(num_elts - 1);
800#ifdef QSORT_ORDER_GUESS
801 qsort_break_even = QSORT_BREAK_EVEN;
802#else
803#define qsort_break_even QSORT_BREAK_EVEN
804#endif
805 for ( ; ; ) {
806 if ((part_right - part_left) >= qsort_break_even) {
807 /* OK, this is gonna get hairy, so lets try to document all the
808 concepts and abbreviations and variables and what they keep
809 track of:
810
811 pc: pivot chunk - the set of array elements we accumulate in the
812 middle of the partition, all equal in value to the original
813 pivot element selected. The pc is defined by:
814
815 pc_left - the leftmost array index of the pc
816 pc_right - the rightmost array index of the pc
817
818 we start with pc_left == pc_right and only one element
819 in the pivot chunk (but it can grow during the scan).
820
821 u: uncompared elements - the set of elements in the partition
822 we have not yet compared to the pivot value. There are two
823 uncompared sets during the scan - one to the left of the pc
824 and one to the right.
825
826 u_right - the rightmost index of the left side's uncompared set
827 u_left - the leftmost index of the right side's uncompared set
828
829 The leftmost index of the left sides's uncompared set
830 doesn't need its own variable because it is always defined
831 by the leftmost edge of the whole partition (part_left). The
832 same goes for the rightmost edge of the right partition
833 (part_right).
834
835 We know there are no uncompared elements on the left once we
836 get u_right < part_left and no uncompared elements on the
837 right once u_left > part_right. When both these conditions
838 are met, we have completed the scan of the partition.
839
840 Any elements which are between the pivot chunk and the
841 uncompared elements should be less than the pivot value on
842 the left side and greater than the pivot value on the right
843 side (in fact, the goal of the whole algorithm is to arrange
844 for that to be true and make the groups of less-than and
845 greater-then elements into new partitions to sort again).
846
847 As you marvel at the complexity of the code and wonder why it
848 has to be so confusing. Consider some of the things this level
849 of confusion brings:
850
851 Once I do a compare, I squeeze every ounce of juice out of it. I
852 never do compare calls I don't have to do, and I certainly never
853 do redundant calls.
854
855 I also never swap any elements unless I can prove there is a
856 good reason. Many sort algorithms will swap a known value with
857 an uncompared value just to get things in the right place (or
858 avoid complexity :-), but that uncompared value, once it gets
859 compared, may then have to be swapped again. A lot of the
860 complexity of this code is due to the fact that it never swaps
861 anything except compared values, and it only swaps them when the
862 compare shows they are out of position.
863 */
864 int pc_left, pc_right;
865 int u_right, u_left;
866
867 int s;
868
869 pc_left = ((part_left + part_right) / 2);
870 pc_right = pc_left;
871 u_right = pc_left - 1;
872 u_left = pc_right + 1;
873
874 /* Qsort works best when the pivot value is also the median value
875 in the partition (unfortunately you can't find the median value
876 without first sorting :-), so to give the algorithm a helping
877 hand, we pick 3 elements and sort them and use the median value
878 of that tiny set as the pivot value.
879
880 Some versions of qsort like to use the left middle and right as
881 the 3 elements to sort so they can insure the ends of the
882 partition will contain values which will stop the scan in the
883 compare loop, but when you have to call an arbitrarily complex
884 routine to do a compare, its really better to just keep track of
885 array index values to know when you hit the edge of the
886 partition and avoid the extra compare. An even better reason to
887 avoid using a compare call is the fact that you can drop off the
888 edge of the array if someone foolishly provides you with an
889 unstable compare function that doesn't always provide consistent
890 results.
891
892 So, since it is simpler for us to compare the three adjacent
893 elements in the middle of the partition, those are the ones we
894 pick here (conveniently pointed at by u_right, pc_left, and
895 u_left). The values of the left, center, and right elements
896 are refered to as l c and r in the following comments.
897 */
898
899#ifdef QSORT_ORDER_GUESS
900 swapped = 0;
901#endif
902 s = qsort_cmp(u_right, pc_left);
903 if (s < 0) {
904 /* l < c */
905 s = qsort_cmp(pc_left, u_left);
906 /* if l < c, c < r - already in order - nothing to do */
907 if (s == 0) {
908 /* l < c, c == r - already in order, pc grows */
909 ++pc_right;
910 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
911 } else if (s > 0) {
912 /* l < c, c > r - need to know more */
913 s = qsort_cmp(u_right, u_left);
914 if (s < 0) {
915 /* l < c, c > r, l < r - swap c & r to get ordered */
916 qsort_swap(pc_left, u_left);
917 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
918 } else if (s == 0) {
919 /* l < c, c > r, l == r - swap c&r, grow pc */
920 qsort_swap(pc_left, u_left);
921 --pc_left;
922 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
923 } else {
924 /* l < c, c > r, l > r - make lcr into rlc to get ordered */
925 qsort_rotate(pc_left, u_right, u_left);
926 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
927 }
928 }
929 } else if (s == 0) {
930 /* l == c */
931 s = qsort_cmp(pc_left, u_left);
932 if (s < 0) {
933 /* l == c, c < r - already in order, grow pc */
934 --pc_left;
935 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
936 } else if (s == 0) {
937 /* l == c, c == r - already in order, grow pc both ways */
938 --pc_left;
939 ++pc_right;
940 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
941 } else {
942 /* l == c, c > r - swap l & r, grow pc */
943 qsort_swap(u_right, u_left);
944 ++pc_right;
945 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
946 }
947 } else {
948 /* l > c */
949 s = qsort_cmp(pc_left, u_left);
950 if (s < 0) {
951 /* l > c, c < r - need to know more */
952 s = qsort_cmp(u_right, u_left);
953 if (s < 0) {
954 /* l > c, c < r, l < r - swap l & c to get ordered */
955 qsort_swap(u_right, pc_left);
956 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
957 } else if (s == 0) {
958 /* l > c, c < r, l == r - swap l & c, grow pc */
959 qsort_swap(u_right, pc_left);
960 ++pc_right;
961 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
962 } else {
963 /* l > c, c < r, l > r - rotate lcr into crl to order */
964 qsort_rotate(u_right, pc_left, u_left);
965 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
966 }
967 } else if (s == 0) {
968 /* l > c, c == r - swap ends, grow pc */
969 qsort_swap(u_right, u_left);
970 --pc_left;
971 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
972 } else {
973 /* l > c, c > r - swap ends to get in order */
974 qsort_swap(u_right, u_left);
975 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
976 }
977 }
978 /* We now know the 3 middle elements have been compared and
979 arranged in the desired order, so we can shrink the uncompared
980 sets on both sides
981 */
982 --u_right;
983 ++u_left;
984 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
985
986 /* The above massive nested if was the simple part :-). We now have
987 the middle 3 elements ordered and we need to scan through the
988 uncompared sets on either side, swapping elements that are on
989 the wrong side or simply shuffling equal elements around to get
990 all equal elements into the pivot chunk.
991 */
992
993 for ( ; ; ) {
994 int still_work_on_left;
995 int still_work_on_right;
996
997 /* Scan the uncompared values on the left. If I find a value
998 equal to the pivot value, move it over so it is adjacent to
999 the pivot chunk and expand the pivot chunk. If I find a value
1000 less than the pivot value, then just leave it - its already
1001 on the correct side of the partition. If I find a greater
1002 value, then stop the scan.
1003 */
1004 while ((still_work_on_left = (u_right >= part_left))) {
1005 s = qsort_cmp(u_right, pc_left);
1006 if (s < 0) {
1007 --u_right;
1008 } else if (s == 0) {
1009 --pc_left;
1010 if (pc_left != u_right) {
1011 qsort_swap(u_right, pc_left);
1012 }
1013 --u_right;
1014 } else {
1015 break;
1016 }
1017 qsort_assert(u_right < pc_left);
1018 qsort_assert(pc_left <= pc_right);
1019 qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0);
1020 qsort_assert(qsort_cmp(pc_left, pc_right) == 0);
1021 }
1022
1023 /* Do a mirror image scan of uncompared values on the right
1024 */
1025 while ((still_work_on_right = (u_left <= part_right))) {
1026 s = qsort_cmp(pc_right, u_left);
1027 if (s < 0) {
1028 ++u_left;
1029 } else if (s == 0) {
1030 ++pc_right;
1031 if (pc_right != u_left) {
1032 qsort_swap(pc_right, u_left);
1033 }
1034 ++u_left;
1035 } else {
1036 break;
1037 }
1038 qsort_assert(u_left > pc_right);
1039 qsort_assert(pc_left <= pc_right);
1040 qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0);
1041 qsort_assert(qsort_cmp(pc_left, pc_right) == 0);
1042 }
1043
1044 if (still_work_on_left) {
1045 /* I know I have a value on the left side which needs to be
1046 on the right side, but I need to know more to decide
1047 exactly the best thing to do with it.
1048 */
1049 if (still_work_on_right) {
1050 /* I know I have values on both side which are out of
1051 position. This is a big win because I kill two birds
1052 with one swap (so to speak). I can advance the
1053 uncompared pointers on both sides after swapping both
1054 of them into the right place.
1055 */
1056 qsort_swap(u_right, u_left);
1057 --u_right;
1058 ++u_left;
1059 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
1060 } else {
1061 /* I have an out of position value on the left, but the
1062 right is fully scanned, so I "slide" the pivot chunk
1063 and any less-than values left one to make room for the
1064 greater value over on the right. If the out of position
1065 value is immediately adjacent to the pivot chunk (there
1066 are no less-than values), I can do that with a swap,
1067 otherwise, I have to rotate one of the less than values
1068 into the former position of the out of position value
1069 and the right end of the pivot chunk into the left end
1070 (got all that?).
1071 */
1072 --pc_left;
1073 if (pc_left == u_right) {
1074 qsort_swap(u_right, pc_right);
1075 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
1076 } else {
1077 qsort_rotate(u_right, pc_left, pc_right);
1078 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
1079 }
1080 --pc_right;
1081 --u_right;
1082 }
1083 } else if (still_work_on_right) {
1084 /* Mirror image of complex case above: I have an out of
1085 position value on the right, but the left is fully
1086 scanned, so I need to shuffle things around to make room
1087 for the right value on the left.
1088 */
1089 ++pc_right;
1090 if (pc_right == u_left) {
1091 qsort_swap(u_left, pc_left);
1092 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1093 } else {
1094 qsort_rotate(pc_right, pc_left, u_left);
1095 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1096 }
1097 ++pc_left;
1098 ++u_left;
1099 } else {
1100 /* No more scanning required on either side of partition,
1101 break out of loop and figure out next set of partitions
1102 */
1103 break;
1104 }
1105 }
1106
1107 /* The elements in the pivot chunk are now in the right place. They
1108 will never move or be compared again. All I have to do is decide
1109 what to do with the stuff to the left and right of the pivot
1110 chunk.
1111
1112 Notes on the QSORT_ORDER_GUESS ifdef code:
1113
1114 1. If I just built these partitions without swapping any (or
1115 very many) elements, there is a chance that the elements are
1116 already ordered properly (being properly ordered will
1117 certainly result in no swapping, but the converse can't be
1118 proved :-).
1119
1120 2. A (properly written) insertion sort will run faster on
1121 already ordered data than qsort will.
1122
1123 3. Perhaps there is some way to make a good guess about
1124 switching to an insertion sort earlier than partition size 6
1125 (for instance - we could save the partition size on the stack
1126 and increase the size each time we find we didn't swap, thus
1127 switching to insertion sort earlier for partitions with a
1128 history of not swapping).
1129
1130 4. Naturally, if I just switch right away, it will make
1131 artificial benchmarks with pure ascending (or descending)
1132 data look really good, but is that a good reason in general?
1133 Hard to say...
1134 */
1135
1136#ifdef QSORT_ORDER_GUESS
1137 if (swapped < 3) {
1138#if QSORT_ORDER_GUESS == 1
1139 qsort_break_even = (part_right - part_left) + 1;
1140#endif
1141#if QSORT_ORDER_GUESS == 2
1142 qsort_break_even *= 2;
1143#endif
1144#if QSORT_ORDER_GUESS == 3
901017d6 1145 const int prev_break = qsort_break_even;
84d4ea48
JH
1146 qsort_break_even *= qsort_break_even;
1147 if (qsort_break_even < prev_break) {
1148 qsort_break_even = (part_right - part_left) + 1;
1149 }
1150#endif
1151 } else {
1152 qsort_break_even = QSORT_BREAK_EVEN;
1153 }
1154#endif
1155
1156 if (part_left < pc_left) {
1157 /* There are elements on the left which need more processing.
1158 Check the right as well before deciding what to do.
1159 */
1160 if (pc_right < part_right) {
1161 /* We have two partitions to be sorted. Stack the biggest one
1162 and process the smallest one on the next iteration. This
1163 minimizes the stack height by insuring that any additional
1164 stack entries must come from the smallest partition which
1165 (because it is smallest) will have the fewest
1166 opportunities to generate additional stack entries.
1167 */
1168 if ((part_right - pc_right) > (pc_left - part_left)) {
1169 /* stack the right partition, process the left */
1170 partition_stack[next_stack_entry].left = pc_right + 1;
1171 partition_stack[next_stack_entry].right = part_right;
1172#ifdef QSORT_ORDER_GUESS
1173 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even;
1174#endif
1175 part_right = pc_left - 1;
1176 } else {
1177 /* stack the left partition, process the right */
1178 partition_stack[next_stack_entry].left = part_left;
1179 partition_stack[next_stack_entry].right = pc_left - 1;
1180#ifdef QSORT_ORDER_GUESS
1181 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even;
1182#endif
1183 part_left = pc_right + 1;
1184 }
1185 qsort_assert(next_stack_entry < QSORT_MAX_STACK);
1186 ++next_stack_entry;
1187 } else {
1188 /* The elements on the left are the only remaining elements
1189 that need sorting, arrange for them to be processed as the
1190 next partition.
1191 */
1192 part_right = pc_left - 1;
1193 }
1194 } else if (pc_right < part_right) {
1195 /* There is only one chunk on the right to be sorted, make it
1196 the new partition and loop back around.
1197 */
1198 part_left = pc_right + 1;
1199 } else {
1200 /* This whole partition wound up in the pivot chunk, so
1201 we need to get a new partition off the stack.
1202 */
1203 if (next_stack_entry == 0) {
1204 /* the stack is empty - we are done */
1205 break;
1206 }
1207 --next_stack_entry;
1208 part_left = partition_stack[next_stack_entry].left;
1209 part_right = partition_stack[next_stack_entry].right;
1210#ifdef QSORT_ORDER_GUESS
1211 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even;
1212#endif
1213 }
1214 } else {
1215 /* This partition is too small to fool with qsort complexity, just
1216 do an ordinary insertion sort to minimize overhead.
1217 */
1218 int i;
1219 /* Assume 1st element is in right place already, and start checking
1220 at 2nd element to see where it should be inserted.
1221 */
1222 for (i = part_left + 1; i <= part_right; ++i) {
1223 int j;
1224 /* Scan (backwards - just in case 'i' is already in right place)
1225 through the elements already sorted to see if the ith element
1226 belongs ahead of one of them.
1227 */
1228 for (j = i - 1; j >= part_left; --j) {
1229 if (qsort_cmp(i, j) >= 0) {
1230 /* i belongs right after j
1231 */
1232 break;
1233 }
1234 }
1235 ++j;
1236 if (j != i) {
1237 /* Looks like we really need to move some things
1238 */
1239 int k;
1240 temp = array[i];
1241 for (k = i - 1; k >= j; --k)
1242 array[k + 1] = array[k];
1243 array[j] = temp;
1244 }
1245 }
1246
1247 /* That partition is now sorted, grab the next one, or get out
1248 of the loop if there aren't any more.
1249 */
1250
1251 if (next_stack_entry == 0) {
1252 /* the stack is empty - we are done */
1253 break;
1254 }
1255 --next_stack_entry;
1256 part_left = partition_stack[next_stack_entry].left;
1257 part_right = partition_stack[next_stack_entry].right;
1258#ifdef QSORT_ORDER_GUESS
1259 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even;
1260#endif
1261 }
1262 }
1263
1264 /* Believe it or not, the array is sorted at this point! */
1265}
1266
84d4ea48
JH
1267/* Stabilize what is, presumably, an otherwise unstable sort method.
1268 * We do that by allocating (or having on hand) an array of pointers
1269 * that is the same size as the original array of elements to be sorted.
1270 * We initialize this parallel array with the addresses of the original
1271 * array elements. This indirection can make you crazy.
1272 * Some pictures can help. After initializing, we have
1273 *
1274 * indir list1
1275 * +----+ +----+
1276 * | | --------------> | | ------> first element to be sorted
1277 * +----+ +----+
1278 * | | --------------> | | ------> second element to be sorted
1279 * +----+ +----+
1280 * | | --------------> | | ------> third element to be sorted
1281 * +----+ +----+
1282 * ...
1283 * +----+ +----+
1284 * | | --------------> | | ------> n-1st element to be sorted
1285 * +----+ +----+
1286 * | | --------------> | | ------> n-th element to be sorted
1287 * +----+ +----+
1288 *
1289 * During the sort phase, we leave the elements of list1 where they are,
1290 * and sort the pointers in the indirect array in the same order determined
1291 * by the original comparison routine on the elements pointed to.
1292 * Because we don't move the elements of list1 around through
1293 * this phase, we can break ties on elements that compare equal
1294 * using their address in the list1 array, ensuring stabilty.
1295 * This leaves us with something looking like
1296 *
1297 * indir list1
1298 * +----+ +----+
1299 * | | --+ +---> | | ------> first element to be sorted
1300 * +----+ | | +----+
1301 * | | --|-------|---> | | ------> second element to be sorted
1302 * +----+ | | +----+
1303 * | | --|-------+ +-> | | ------> third element to be sorted
1304 * +----+ | | +----+
1305 * ...
1306 * +----+ | | | | +----+
1307 * | | ---|-+ | +--> | | ------> n-1st element to be sorted
1308 * +----+ | | +----+
1309 * | | ---+ +----> | | ------> n-th element to be sorted
1310 * +----+ +----+
1311 *
1312 * where the i-th element of the indirect array points to the element
1313 * that should be i-th in the sorted array. After the sort phase,
1314 * we have to put the elements of list1 into the places
1315 * dictated by the indirect array.
1316 */
1317
84d4ea48
JH
1318
1319static I32
1320cmpindir(pTHX_ gptr a, gptr b)
1321{
1322 I32 sense;
901017d6
AL
1323 gptr * const ap = (gptr *)a;
1324 gptr * const bp = (gptr *)b;
84d4ea48 1325
147f47de 1326 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)) == 0)
84d4ea48
JH
1327 sense = (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1328 return sense;
1329}
1330
6c3fb703
NC
1331static I32
1332cmpindir_desc(pTHX_ gptr a, gptr b)
1333{
1334 I32 sense;
901017d6
AL
1335 gptr * const ap = (gptr *)a;
1336 gptr * const bp = (gptr *)b;
6c3fb703
NC
1337
1338 /* Reverse the default */
1339 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)))
1340 return -sense;
1341 /* But don't reverse the stability test. */
1342 return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1343
1344}
1345
84d4ea48 1346STATIC void
6c3fb703 1347S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
84d4ea48 1348{
84d4ea48 1349
5fe61d93
SF
1350 dSORTHINTS;
1351
1352 if (SORTHINTS & HINT_SORT_STABLE) {
84d4ea48
JH
1353 register gptr **pp, *q;
1354 register size_t n, j, i;
1355 gptr *small[SMALLSORT], **indir, tmp;
1356 SVCOMPARE_t savecmp;
1357 if (nmemb <= 1) return; /* sorted trivially */
4eb872f6 1358
84d4ea48
JH
1359 /* Small arrays can use the stack, big ones must be allocated */
1360 if (nmemb <= SMALLSORT) indir = small;
1361 else { New(1799, indir, nmemb, gptr *); }
4eb872f6 1362
84d4ea48
JH
1363 /* Copy pointers to original array elements into indirect array */
1364 for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++;
4eb872f6 1365
147f47de
AB
1366 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
1367 PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */
4eb872f6 1368
84d4ea48 1369 /* sort, with indirection */
6c3fb703
NC
1370 S_qsortsvu(aTHX_ (gptr *)indir, nmemb,
1371 flags ? cmpindir_desc : cmpindir);
4eb872f6 1372
84d4ea48
JH
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 vacuosly 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 */
147f47de 1413 PL_sort_RealCmp = savecmp;
6c3fb703
NC
1414 } else if (flags) {
1415 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 S_qsortsvu(aTHX_ list1, nmemb, cmp);
1419 /* restore prevailing comparison routine */
1420 PL_sort_RealCmp = savecmp;
c53fc8a6
JH
1421 } else {
1422 S_qsortsvu(aTHX_ list1, nmemb, cmp);
84d4ea48
JH
1423 }
1424}
4eb872f6
JL
1425
1426/*
ccfc67b7
JH
1427=head1 Array Manipulation Functions
1428
84d4ea48
JH
1429=for apidoc sortsv
1430
1431Sort an array. Here is an example:
1432
4eb872f6 1433 sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);
84d4ea48 1434
78210658
AD
1435See lib/sort.pm for details about controlling the sorting algorithm.
1436
84d4ea48
JH
1437=cut
1438*/
4eb872f6 1439
84d4ea48
JH
1440void
1441Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1442{
6c3fb703
NC
1443 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
1444 = S_mergesortsv;
5fe61d93
SF
1445 dSORTHINTS;
1446 const I32 hints = SORTHINTS;
78210658
AD
1447 if (hints & HINT_SORT_QUICKSORT) {
1448 sortsvp = S_qsortsv;
1449 }
1450 else {
1451 /* The default as of 5.8.0 is mergesort */
1452 sortsvp = S_mergesortsv;
84d4ea48 1453 }
4eb872f6 1454
6c3fb703
NC
1455 sortsvp(aTHX_ array, nmemb, cmp, 0);
1456}
1457
1458
b7787f18 1459static void
6c3fb703
NC
1460S_sortsv_desc(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1461{
1462 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
1463 = S_mergesortsv;
5fe61d93
SF
1464 dSORTHINTS;
1465 const I32 hints = SORTHINTS;
6c3fb703
NC
1466 if (hints & HINT_SORT_QUICKSORT) {
1467 sortsvp = S_qsortsv;
1468 }
1469 else {
1470 /* The default as of 5.8.0 is mergesort */
1471 sortsvp = S_mergesortsv;
1472 }
1473
1474 sortsvp(aTHX_ array, nmemb, cmp, 1);
84d4ea48
JH
1475}
1476
4d562308
SF
1477#define SvNSIOK(sv) ((SvFLAGS(sv) & SVf_NOK) || ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK))
1478#define SvSIOK(sv) ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK)
1479#define SvNSIV(sv) ( SvNOK(sv) ? SvNVX(sv) : ( SvSIOK(sv) ? SvIVX(sv) : sv_2nv(sv) ) )
1480
84d4ea48
JH
1481PP(pp_sort)
1482{
27da23d5 1483 dVAR; dSP; dMARK; dORIGMARK;
fe1bc4cf
DM
1484 register SV **p1 = ORIGMARK+1, **p2;
1485 register I32 max, i;
1486 AV* av = Nullav;
84d4ea48
JH
1487 HV *stash;
1488 GV *gv;
1489 CV *cv = 0;
1490 I32 gimme = GIMME;
1491 OP* nextop = PL_op->op_next;
1492 I32 overloading = 0;
1493 bool hasargs = FALSE;
1494 I32 is_xsub = 0;
fe1bc4cf 1495 I32 sorting_av = 0;
901017d6
AL
1496 const U8 priv = PL_op->op_private;
1497 const U8 flags = PL_op->op_flags;
6c3fb703
NC
1498 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1499 = Perl_sortsv;
4d562308 1500 I32 all_SIVs = 1;
84d4ea48
JH
1501
1502 if (gimme != G_ARRAY) {
1503 SP = MARK;
1504 RETPUSHUNDEF;
1505 }
1506
1507 ENTER;
1508 SAVEVPTR(PL_sortcop);
471178c0
NC
1509 if (flags & OPf_STACKED) {
1510 if (flags & OPf_SPECIAL) {
84d4ea48
JH
1511 OP *kid = cLISTOP->op_first->op_sibling; /* pass pushmark */
1512 kid = kUNOP->op_first; /* pass rv2gv */
1513 kid = kUNOP->op_first; /* pass leave */
1514 PL_sortcop = kid->op_next;
1515 stash = CopSTASH(PL_curcop);
1516 }
1517 else {
1518 cv = sv_2cv(*++MARK, &stash, &gv, 0);
1519 if (cv && SvPOK(cv)) {
349d4f2f 1520 const char *proto = SvPV_nolen_const((SV*)cv);
84d4ea48
JH
1521 if (proto && strEQ(proto, "$$")) {
1522 hasargs = TRUE;
1523 }
1524 }
1525 if (!(cv && CvROOT(cv))) {
1526 if (cv && CvXSUB(cv)) {
1527 is_xsub = 1;
1528 }
1529 else if (gv) {
1530 SV *tmpstr = sv_newmortal();
1531 gv_efullname3(tmpstr, gv, Nullch);
35c1215d
NC
1532 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called",
1533 tmpstr);
84d4ea48
JH
1534 }
1535 else {
1536 DIE(aTHX_ "Undefined subroutine in sort");
1537 }
1538 }
1539
1540 if (is_xsub)
1541 PL_sortcop = (OP*)cv;
1542 else {
1543 PL_sortcop = CvSTART(cv);
1544 SAVEVPTR(CvROOT(cv)->op_ppaddr);
1545 CvROOT(cv)->op_ppaddr = PL_ppaddr[OP_NULL];
1546
dd2155a4 1547 PAD_SET_CUR(CvPADLIST(cv), 1);
84d4ea48
JH
1548 }
1549 }
1550 }
1551 else {
1552 PL_sortcop = Nullop;
1553 stash = CopSTASH(PL_curcop);
1554 }
1555
fe1bc4cf
DM
1556 /* optimiser converts "@a = sort @a" to "sort \@a";
1557 * in case of tied @a, pessimise: push (@a) onto stack, then assign
1558 * result back to @a at the end of this function */
0723351e 1559 if (priv & OPpSORT_INPLACE) {
fe1bc4cf
DM
1560 assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV);
1561 (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */
1562 av = (AV*)(*SP);
1563 max = AvFILL(av) + 1;
1564 if (SvMAGICAL(av)) {
1565 MEXTEND(SP, max);
1566 p2 = SP;
fe2774ed 1567 for (i=0; i < max; i++) {
fe1bc4cf
DM
1568 SV **svp = av_fetch(av, i, FALSE);
1569 *SP++ = (svp) ? *svp : Nullsv;
1570 }
1571 }
1572 else {
1573 p1 = p2 = AvARRAY(av);
1574 sorting_av = 1;
1575 }
1576 }
1577 else {
1578 p2 = MARK+1;
1579 max = SP - MARK;
1580 }
1581
0723351e 1582 if (priv & OPpSORT_DESCEND) {
6c3fb703
NC
1583 sortsvp = S_sortsv_desc;
1584 }
1585
83a44efe
SF
1586 /* shuffle stack down, removing optional initial cv (p1!=p2), plus
1587 * any nulls; also stringify or converting to integer or number as
1588 * required any args */
fe1bc4cf
DM
1589 for (i=max; i > 0 ; i--) {
1590 if ((*p1 = *p2++)) { /* Weed out nulls. */
1591 SvTEMP_off(*p1);
83a44efe
SF
1592 if (!PL_sortcop) {
1593 if (priv & OPpSORT_NUMERIC) {
1594 if (priv & OPpSORT_INTEGER) {
1595 if (!SvIOK(*p1)) {
1596 if (SvAMAGIC(*p1))
1597 overloading = 1;
1598 else
1599 (void)sv_2iv(*p1);
1600 }
1601 }
1602 else {
4d562308 1603 if (!SvNSIOK(*p1)) {
83a44efe
SF
1604 if (SvAMAGIC(*p1))
1605 overloading = 1;
1606 else
1607 (void)sv_2nv(*p1);
1608 }
4d562308
SF
1609 if (all_SIVs && !SvSIOK(*p1))
1610 all_SIVs = 0;
83a44efe
SF
1611 }
1612 }
1613 else {
1614 if (!SvPOK(*p1)) {
83a44efe
SF
1615 if (SvAMAGIC(*p1))
1616 overloading = 1;
1617 else
83003860
NC
1618 (void)sv_2pv_flags(*p1, 0,
1619 SV_GMAGIC|SV_CONST_RETURN);
83a44efe
SF
1620 }
1621 }
84d4ea48 1622 }
fe1bc4cf 1623 p1++;
84d4ea48 1624 }
fe1bc4cf
DM
1625 else
1626 max--;
84d4ea48 1627 }
fe1bc4cf
DM
1628 if (sorting_av)
1629 AvFILLp(av) = max-1;
1630
1631 if (max > 1) {
471178c0 1632 SV **start;
fe1bc4cf 1633 if (PL_sortcop) {
84d4ea48
JH
1634 PERL_CONTEXT *cx;
1635 SV** newsp;
901017d6 1636 const bool oldcatch = CATCH_GET;
84d4ea48
JH
1637
1638 SAVETMPS;
1639 SAVEOP();
1640
1641 CATCH_SET(TRUE);
1642 PUSHSTACKi(PERLSI_SORT);
1643 if (!hasargs && !is_xsub) {
1644 if (PL_sortstash != stash || !PL_firstgv || !PL_secondgv) {
1645 SAVESPTR(PL_firstgv);
1646 SAVESPTR(PL_secondgv);
1647 PL_firstgv = gv_fetchpv("a", TRUE, SVt_PV);
1648 PL_secondgv = gv_fetchpv("b", TRUE, SVt_PV);
1649 PL_sortstash = stash;
1650 }
84d4ea48
JH
1651 SAVESPTR(GvSV(PL_firstgv));
1652 SAVESPTR(GvSV(PL_secondgv));
1653 }
1654
1655 PUSHBLOCK(cx, CXt_NULL, PL_stack_base);
471178c0 1656 if (!(flags & OPf_SPECIAL)) {
84d4ea48
JH
1657 cx->cx_type = CXt_SUB;
1658 cx->blk_gimme = G_SCALAR;
1659 PUSHSUB(cx);
84d4ea48
JH
1660 }
1661 PL_sortcxix = cxstack_ix;
1662
1663 if (hasargs && !is_xsub) {
1664 /* This is mostly copied from pp_entersub */
dd2155a4 1665 AV *av = (AV*)PAD_SVl(0);
84d4ea48 1666
84d4ea48
JH
1667 cx->blk_sub.savearray = GvAV(PL_defgv);
1668 GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av);
dd2155a4 1669 CX_CURPAD_SAVE(cx->blk_sub);
84d4ea48
JH
1670 cx->blk_sub.argarray = av;
1671 }
471178c0
NC
1672
1673 start = p1 - max;
1674 sortsvp(aTHX_ start, max,
1675 is_xsub ? sortcv_xsub : hasargs ? sortcv_stacked : sortcv);
84d4ea48
JH
1676
1677 POPBLOCK(cx,PL_curpm);
1678 PL_stack_sp = newsp;
1679 POPSTACK;
1680 CATCH_SET(oldcatch);
1681 }
fe1bc4cf 1682 else {
84d4ea48 1683 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */
471178c0
NC
1684 start = sorting_av ? AvARRAY(av) : ORIGMARK+1;
1685 sortsvp(aTHX_ start, max,
0723351e 1686 (priv & OPpSORT_NUMERIC)
4d562308 1687 ? ( ( ( priv & OPpSORT_INTEGER) || all_SIVs)
84d4ea48 1688 ? ( overloading ? amagic_i_ncmp : sv_i_ncmp)
4d562308 1689 : ( overloading ? amagic_ncmp : sv_ncmp ) )
84d4ea48
JH
1690 : ( IN_LOCALE_RUNTIME
1691 ? ( overloading
1692 ? amagic_cmp_locale
1693 : sv_cmp_locale_static)
1694 : ( overloading ? amagic_cmp : sv_cmp_static)));
471178c0 1695 }
0723351e 1696 if (priv & OPpSORT_REVERSE) {
471178c0
NC
1697 SV **q = start+max-1;
1698 while (start < q) {
1699 SV *tmp = *start;
1700 *start++ = *q;
1701 *q-- = tmp;
84d4ea48
JH
1702 }
1703 }
1704 }
fe1bc4cf
DM
1705 if (av && !sorting_av) {
1706 /* simulate pp_aassign of tied AV */
901017d6
AL
1707 SV** const base = ORIGMARK+1;
1708 for (i=0; i < max; i++) {
1709 base[i] = newSVsv(base[i]);
fe1bc4cf
DM
1710 }
1711 av_clear(av);
1712 av_extend(av, max);
1713 for (i=0; i < max; i++) {
901017d6
AL
1714 SV * const sv = base[i];
1715 SV **didstore = av_store(av, i, sv);
fe1bc4cf
DM
1716 if (SvSMAGICAL(sv))
1717 mg_set(sv);
1718 if (!didstore)
1719 sv_2mortal(sv);
1720 }
1721 }
84d4ea48 1722 LEAVE;
fe1bc4cf 1723 PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max);
84d4ea48
JH
1724 return nextop;
1725}
1726
1727static I32
1728sortcv(pTHX_ SV *a, SV *b)
1729{
27da23d5 1730 dVAR;
901017d6
AL
1731 const I32 oldsaveix = PL_savestack_ix;
1732 const I32 oldscopeix = PL_scopestack_ix;
84d4ea48
JH
1733 I32 result;
1734 GvSV(PL_firstgv) = a;
1735 GvSV(PL_secondgv) = b;
1736 PL_stack_sp = PL_stack_base;
1737 PL_op = PL_sortcop;
1738 CALLRUNOPS(aTHX);
1739 if (PL_stack_sp != PL_stack_base + 1)
1740 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1741 if (!SvNIOKp(*PL_stack_sp))
1742 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1743 result = SvIV(*PL_stack_sp);
1744 while (PL_scopestack_ix > oldscopeix) {
1745 LEAVE;
1746 }
1747 leave_scope(oldsaveix);
1748 return result;
1749}
1750
1751static I32
1752sortcv_stacked(pTHX_ SV *a, SV *b)
1753{
27da23d5 1754 dVAR;
901017d6
AL
1755 const I32 oldsaveix = PL_savestack_ix;
1756 const I32 oldscopeix = PL_scopestack_ix;
84d4ea48 1757 I32 result;
901017d6 1758 AV * const av = GvAV(PL_defgv);
84d4ea48
JH
1759
1760 if (AvMAX(av) < 1) {
1761 SV** ary = AvALLOC(av);
1762 if (AvARRAY(av) != ary) {
1763 AvMAX(av) += AvARRAY(av) - AvALLOC(av);
f880fe2f 1764 SvPV_set(av, (char*)ary);
84d4ea48
JH
1765 }
1766 if (AvMAX(av) < 1) {
1767 AvMAX(av) = 1;
1768 Renew(ary,2,SV*);
f880fe2f 1769 SvPV_set(av, (char*)ary);
84d4ea48
JH
1770 }
1771 }
1772 AvFILLp(av) = 1;
1773
1774 AvARRAY(av)[0] = a;
1775 AvARRAY(av)[1] = b;
1776 PL_stack_sp = PL_stack_base;
1777 PL_op = PL_sortcop;
1778 CALLRUNOPS(aTHX);
1779 if (PL_stack_sp != PL_stack_base + 1)
1780 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1781 if (!SvNIOKp(*PL_stack_sp))
1782 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1783 result = SvIV(*PL_stack_sp);
1784 while (PL_scopestack_ix > oldscopeix) {
1785 LEAVE;
1786 }
1787 leave_scope(oldsaveix);
1788 return result;
1789}
1790
1791static I32
1792sortcv_xsub(pTHX_ SV *a, SV *b)
1793{
27da23d5 1794 dVAR; dSP;
901017d6
AL
1795 const I32 oldsaveix = PL_savestack_ix;
1796 const I32 oldscopeix = PL_scopestack_ix;
1797 CV * const cv=(CV*)PL_sortcop;
84d4ea48 1798 I32 result;
84d4ea48
JH
1799
1800 SP = PL_stack_base;
1801 PUSHMARK(SP);
1802 EXTEND(SP, 2);
1803 *++SP = a;
1804 *++SP = b;
1805 PUTBACK;
1806 (void)(*CvXSUB(cv))(aTHX_ cv);
1807 if (PL_stack_sp != PL_stack_base + 1)
1808 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1809 if (!SvNIOKp(*PL_stack_sp))
1810 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1811 result = SvIV(*PL_stack_sp);
1812 while (PL_scopestack_ix > oldscopeix) {
1813 LEAVE;
1814 }
1815 leave_scope(oldsaveix);
1816 return result;
1817}
1818
1819
1820static I32
1821sv_ncmp(pTHX_ SV *a, SV *b)
1822{
901017d6
AL
1823 const NV nv1 = SvNSIV(a);
1824 const NV nv2 = SvNSIV(b);
84d4ea48
JH
1825 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0;
1826}
1827
1828static I32
1829sv_i_ncmp(pTHX_ SV *a, SV *b)
1830{
901017d6
AL
1831 const IV iv1 = SvIV(a);
1832 const IV iv2 = SvIV(b);
84d4ea48
JH
1833 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0;
1834}
901017d6
AL
1835
1836#define tryCALL_AMAGICbin(left,right,meth) \
1837 (PL_amagic_generation && (SvAMAGIC(left)||SvAMAGIC(right))) \
1838 ? amagic_call(left, right, CAT2(meth,_amg), 0) \
1839 : Nullsv;
84d4ea48
JH
1840
1841static I32
1842amagic_ncmp(pTHX_ register SV *a, register SV *b)
1843{
901017d6 1844 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp);
84d4ea48 1845 if (tmpsv) {
84d4ea48 1846 if (SvIOK(tmpsv)) {
901017d6 1847 const I32 i = SvIVX(tmpsv);
84d4ea48
JH
1848 if (i > 0)
1849 return 1;
1850 return i? -1 : 0;
1851 }
901017d6
AL
1852 else {
1853 const NV d = SvNV(tmpsv);
1854 if (d > 0)
1855 return 1;
1856 return d ? -1 : 0;
1857 }
84d4ea48
JH
1858 }
1859 return sv_ncmp(aTHX_ a, b);
1860}
1861
1862static I32
1863amagic_i_ncmp(pTHX_ register SV *a, register SV *b)
1864{
901017d6 1865 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp);
84d4ea48 1866 if (tmpsv) {
84d4ea48 1867 if (SvIOK(tmpsv)) {
901017d6 1868 const I32 i = SvIVX(tmpsv);
84d4ea48
JH
1869 if (i > 0)
1870 return 1;
1871 return i? -1 : 0;
1872 }
901017d6
AL
1873 else {
1874 const NV d = SvNV(tmpsv);
1875 if (d > 0)
1876 return 1;
1877 return d ? -1 : 0;
1878 }
84d4ea48
JH
1879 }
1880 return sv_i_ncmp(aTHX_ a, b);
1881}
1882
1883static I32
1884amagic_cmp(pTHX_ register SV *str1, register SV *str2)
1885{
901017d6 1886 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp);
84d4ea48 1887 if (tmpsv) {
84d4ea48 1888 if (SvIOK(tmpsv)) {
901017d6 1889 const I32 i = SvIVX(tmpsv);
84d4ea48
JH
1890 if (i > 0)
1891 return 1;
1892 return i? -1 : 0;
1893 }
901017d6
AL
1894 else {
1895 const NV d = SvNV(tmpsv);
1896 if (d > 0)
1897 return 1;
1898 return d? -1 : 0;
1899 }
84d4ea48
JH
1900 }
1901 return sv_cmp(str1, str2);
1902}
1903
1904static I32
1905amagic_cmp_locale(pTHX_ register SV *str1, register SV *str2)
1906{
901017d6 1907 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp);
84d4ea48 1908 if (tmpsv) {
84d4ea48 1909 if (SvIOK(tmpsv)) {
901017d6 1910 const I32 i = SvIVX(tmpsv);
84d4ea48
JH
1911 if (i > 0)
1912 return 1;
1913 return i? -1 : 0;
1914 }
901017d6
AL
1915 else {
1916 const NV d = SvNV(tmpsv);
1917 if (d > 0)
1918 return 1;
1919 return d? -1 : 0;
1920 }
84d4ea48
JH
1921 }
1922 return sv_cmp_locale(str1, str2);
1923}
241d1a3b
NC
1924
1925/*
1926 * Local variables:
1927 * c-indentation-style: bsd
1928 * c-basic-offset: 4
1929 * indent-tabs-mode: t
1930 * End:
1931 *
37442d52
RGS
1932 * ex: set ts=8 sts=4 sw=4 noet:
1933 */