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Make sort {} and sort {()} equivalent
[perl5.git] / pp_sort.c
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1/* pp_sort.c
2 *
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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
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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/*
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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"]
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16 */
17
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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
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29#include "EXTERN.h"
30#define PERL_IN_PP_SORT_C
31#include "perl.h"
32
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33#if defined(UNDER_CE)
34/* looks like 'small' is reserved word for WINCE (or somesuch)*/
35#define small xsmall
36#endif
37
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38#define sv_cmp_static Perl_sv_cmp
39#define sv_cmp_locale_static Perl_sv_cmp_locale
40
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41#ifndef SMALLSORT
42#define SMALLSORT (200)
43#endif
44
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45/* Flags for qsortsv and mergesortsv */
46#define SORTf_DESC 1
47#define SORTf_STABLE 2
48#define SORTf_QSORT 4
49
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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 Merge Sort" (SODA '92)
57 *
58 * The integration to Perl is by John P. Linderman <jpl@research.att.com>.
59 *
60 * The code can be distributed under the same terms as Perl itself.
61 *
62 */
63
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64
65typedef char * aptr; /* pointer for arithmetic on sizes */
66typedef SV * gptr; /* pointers in our lists */
67
68/* Binary merge internal sort, with a few special mods
69** for the special perl environment it now finds itself in.
70**
71** Things that were once options have been hotwired
72** to values suitable for this use. In particular, we'll always
73** initialize looking for natural runs, we'll always produce stable
74** output, and we'll always do Peter McIlroy's binary merge.
75*/
76
77/* Pointer types for arithmetic and storage and convenience casts */
78
79#define APTR(P) ((aptr)(P))
80#define GPTP(P) ((gptr *)(P))
81#define GPPP(P) ((gptr **)(P))
82
83
84/* byte offset from pointer P to (larger) pointer Q */
85#define BYTEOFF(P, Q) (APTR(Q) - APTR(P))
86
87#define PSIZE sizeof(gptr)
88
89/* If PSIZE is power of 2, make PSHIFT that power, if that helps */
90
91#ifdef PSHIFT
92#define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT))
93#define PNBYTE(N) ((N) << (PSHIFT))
94#define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N)))
95#else
96/* Leave optimization to compiler */
97#define PNELEM(P, Q) (GPTP(Q) - GPTP(P))
98#define PNBYTE(N) ((N) * (PSIZE))
99#define PINDEX(P, N) (GPTP(P) + (N))
100#endif
101
102/* Pointer into other corresponding to pointer into this */
103#define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P))
104
105#define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim)
106
107
486ec47a 108/* Runs are identified by a pointer in the auxiliary list.
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109** The pointer is at the start of the list,
110** and it points to the start of the next list.
111** NEXT is used as an lvalue, too.
112*/
113
114#define NEXT(P) (*GPPP(P))
115
116
117/* PTHRESH is the minimum number of pairs with the same sense to justify
118** checking for a run and extending it. Note that PTHRESH counts PAIRS,
119** not just elements, so PTHRESH == 8 means a run of 16.
120*/
121
122#define PTHRESH (8)
123
124/* RTHRESH is the number of elements in a run that must compare low
125** to the low element from the opposing run before we justify
126** doing a binary rampup instead of single stepping.
127** In random input, N in a row low should only happen with
128** probability 2^(1-N), so we can risk that we are dealing
129** with orderly input without paying much when we aren't.
130*/
131
132#define RTHRESH (6)
133
134
135/*
136** Overview of algorithm and variables.
137** The array of elements at list1 will be organized into runs of length 2,
138** or runs of length >= 2 * PTHRESH. We only try to form long runs when
139** PTHRESH adjacent pairs compare in the same way, suggesting overall order.
140**
141** Unless otherwise specified, pair pointers address the first of two elements.
142**
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143** b and b+1 are a pair that compare with sense "sense".
144** b is the "bottom" of adjacent pairs that might form a longer run.
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145**
146** p2 parallels b in the list2 array, where runs are defined by
147** a pointer chain.
148**
a0288114 149** t represents the "top" of the adjacent pairs that might extend
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150** the run beginning at b. Usually, t addresses a pair
151** that compares with opposite sense from (b,b+1).
152** However, it may also address a singleton element at the end of list1,
a0288114 153** or it may be equal to "last", the first element beyond list1.
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154**
155** r addresses the Nth pair following b. If this would be beyond t,
156** we back it off to t. Only when r is less than t do we consider the
157** run long enough to consider checking.
158**
159** q addresses a pair such that the pairs at b through q already form a run.
160** Often, q will equal b, indicating we only are sure of the pair itself.
161** However, a search on the previous cycle may have revealed a longer run,
162** so q may be greater than b.
163**
164** p is used to work back from a candidate r, trying to reach q,
165** which would mean b through r would be a run. If we discover such a run,
166** we start q at r and try to push it further towards t.
167** If b through r is NOT a run, we detect the wrong order at (p-1,p).
168** In any event, after the check (if any), we have two main cases.
169**
170** 1) Short run. b <= q < p <= r <= t.
171** b through q is a run (perhaps trivial)
172** q through p are uninteresting pairs
173** p through r is a run
174**
175** 2) Long run. b < r <= q < t.
176** b through q is a run (of length >= 2 * PTHRESH)
177**
178** Note that degenerate cases are not only possible, but likely.
179** For example, if the pair following b compares with opposite sense,
180** then b == q < p == r == t.
181*/
182
183
957d8989 184static IV
d4c19fe8 185dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, const SVCOMPARE_t cmp)
84d4ea48 186{
957d8989 187 I32 sense;
84d4ea48 188 register gptr *b, *p, *q, *t, *p2;
d4c19fe8 189 register gptr *last, *r;
957d8989 190 IV runs = 0;
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191
192 b = list1;
193 last = PINDEX(b, nmemb);
194 sense = (cmp(aTHX_ *b, *(b+1)) > 0);
195 for (p2 = list2; b < last; ) {
196 /* We just started, or just reversed sense.
197 ** Set t at end of pairs with the prevailing sense.
198 */
199 for (p = b+2, t = p; ++p < last; t = ++p) {
200 if ((cmp(aTHX_ *t, *p) > 0) != sense) break;
201 }
202 q = b;
203 /* Having laid out the playing field, look for long runs */
204 do {
205 p = r = b + (2 * PTHRESH);
206 if (r >= t) p = r = t; /* too short to care about */
207 else {
208 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) &&
47127b64 209 ((p -= 2) > q)) {}
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210 if (p <= q) {
211 /* b through r is a (long) run.
212 ** Extend it as far as possible.
213 */
214 p = q = r;
215 while (((p += 2) < t) &&
216 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p;
217 r = p = q + 2; /* no simple pairs, no after-run */
218 }
219 }
220 if (q > b) { /* run of greater than 2 at b */
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221 gptr *savep = p;
222
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223 p = q += 2;
224 /* pick up singleton, if possible */
225 if ((p == t) &&
226 ((t + 1) == last) &&
227 ((cmp(aTHX_ *(p-1), *p) > 0) == sense))
228 savep = r = p = q = last;
957d8989 229 p2 = NEXT(p2) = p2 + (p - b); ++runs;
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230 if (sense)
231 while (b < --p) {
232 const gptr c = *b;
233 *b++ = *p;
234 *p = c;
235 }
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236 p = savep;
237 }
238 while (q < p) { /* simple pairs */
957d8989 239 p2 = NEXT(p2) = p2 + 2; ++runs;
84d4ea48 240 if (sense) {
d4c19fe8 241 const gptr c = *q++;
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242 *(q-1) = *q;
243 *q++ = c;
244 } else q += 2;
245 }
246 if (((b = p) == t) && ((t+1) == last)) {
957d8989 247 NEXT(p2) = p2 + 1; ++runs;
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248 b++;
249 }
250 q = r;
251 } while (b < t);
252 sense = !sense;
253 }
957d8989 254 return runs;
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255}
256
257
3fe0b9a9 258/* The original merge sort, in use since 5.7, was as fast as, or faster than,
957d8989 259 * qsort on many platforms, but slower than qsort, conspicuously so,
3fe0b9a9 260 * on others. The most likely explanation was platform-specific
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261 * differences in cache sizes and relative speeds.
262 *
263 * The quicksort divide-and-conquer algorithm guarantees that, as the
264 * problem is subdivided into smaller and smaller parts, the parts
265 * fit into smaller (and faster) caches. So it doesn't matter how
266 * many levels of cache exist, quicksort will "find" them, and,
e62b3022 267 * as long as smaller is faster, take advantage of them.
957d8989 268 *
3fe0b9a9 269 * By contrast, consider how the original mergesort algorithm worked.
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270 * Suppose we have five runs (each typically of length 2 after dynprep).
271 *
272 * pass base aux
273 * 0 1 2 3 4 5
274 * 1 12 34 5
275 * 2 1234 5
276 * 3 12345
277 * 4 12345
278 *
279 * Adjacent pairs are merged in "grand sweeps" through the input.
280 * This means, on pass 1, the records in runs 1 and 2 aren't revisited until
281 * runs 3 and 4 are merged and the runs from run 5 have been copied.
282 * The only cache that matters is one large enough to hold *all* the input.
283 * On some platforms, this may be many times slower than smaller caches.
284 *
285 * The following pseudo-code uses the same basic merge algorithm,
286 * but in a divide-and-conquer way.
287 *
288 * # merge $runs runs at offset $offset of list $list1 into $list2.
289 * # all unmerged runs ($runs == 1) originate in list $base.
290 * sub mgsort2 {
291 * my ($offset, $runs, $base, $list1, $list2) = @_;
292 *
293 * if ($runs == 1) {
294 * if ($list1 is $base) copy run to $list2
295 * return offset of end of list (or copy)
296 * } else {
297 * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1)
298 * mgsort2($off2, $runs/2, $base, $list2, $list1)
299 * merge the adjacent runs at $offset of $list1 into $list2
300 * return the offset of the end of the merged runs
301 * }
302 * }
303 * mgsort2(0, $runs, $base, $aux, $base);
304 *
305 * For our 5 runs, the tree of calls looks like
306 *
307 * 5
308 * 3 2
309 * 2 1 1 1
310 * 1 1
311 *
312 * 1 2 3 4 5
313 *
314 * and the corresponding activity looks like
315 *
316 * copy runs 1 and 2 from base to aux
317 * merge runs 1 and 2 from aux to base
318 * (run 3 is where it belongs, no copy needed)
319 * merge runs 12 and 3 from base to aux
320 * (runs 4 and 5 are where they belong, no copy needed)
321 * merge runs 4 and 5 from base to aux
322 * merge runs 123 and 45 from aux to base
323 *
324 * Note that we merge runs 1 and 2 immediately after copying them,
325 * while they are still likely to be in fast cache. Similarly,
326 * run 3 is merged with run 12 while it still may be lingering in cache.
327 * This implementation should therefore enjoy much of the cache-friendly
328 * behavior that quicksort does. In addition, it does less copying
329 * than the original mergesort implementation (only runs 1 and 2 are copied)
330 * and the "balancing" of merges is better (merged runs comprise more nearly
331 * equal numbers of original runs).
332 *
333 * The actual cache-friendly implementation will use a pseudo-stack
334 * to avoid recursion, and will unroll processing of runs of length 2,
335 * but it is otherwise similar to the recursive implementation.
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336 */
337
338typedef struct {
339 IV offset; /* offset of 1st of 2 runs at this level */
340 IV runs; /* how many runs must be combined into 1 */
341} off_runs; /* pseudo-stack element */
342
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343
344static I32
31e9e0a3 345cmp_desc(pTHX_ gptr const a, gptr const b)
6c3fb703 346{
97aff369 347 dVAR;
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348 return -PL_sort_RealCmp(aTHX_ a, b);
349}
350
957d8989 351STATIC void
6c3fb703 352S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
957d8989 353{
97aff369 354 dVAR;
551405c4 355 IV i, run, offset;
957d8989 356 I32 sense, level;
551405c4 357 register gptr *f1, *f2, *t, *b, *p;
957d8989 358 int iwhich;
551405c4 359 gptr *aux;
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360 gptr *p1;
361 gptr small[SMALLSORT];
362 gptr *which[3];
363 off_runs stack[60], *stackp;
d4c19fe8 364 SVCOMPARE_t savecmp = NULL;
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365
366 if (nmemb <= 1) return; /* sorted trivially */
6c3fb703 367
f4f44d65 368 if ((flags & SORTf_DESC) != 0) {
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369 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
370 PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */
371 cmp = cmp_desc;
372 }
373
957d8989 374 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */
486ec47a 375 else { Newx(aux,nmemb,gptr); } /* allocate auxiliary array */
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376 level = 0;
377 stackp = stack;
378 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp);
379 stackp->offset = offset = 0;
380 which[0] = which[2] = base;
381 which[1] = aux;
382 for (;;) {
383 /* On levels where both runs have be constructed (stackp->runs == 0),
384 * merge them, and note the offset of their end, in case the offset
385 * is needed at the next level up. Hop up a level, and,
386 * as long as stackp->runs is 0, keep merging.
387 */
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388 IV runs = stackp->runs;
389 if (runs == 0) {
390 gptr *list1, *list2;
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391 iwhich = level & 1;
392 list1 = which[iwhich]; /* area where runs are now */
393 list2 = which[++iwhich]; /* area for merged runs */
394 do {
551405c4 395 register gptr *l1, *l2, *tp2;
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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
551405c4 425 register gptr *q;
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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 */
486ec47a 552 NEXT(b) = p; /* paralleled pointer for 1st */
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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
JL
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;
84d4ea48
JH
767 struct partition_stack_entry partition_stack[QSORT_MAX_STACK];
768 int next_stack_entry = 0;
84d4ea48
JH
769 int part_left;
770 int part_right;
771#ifdef QSORT_ORDER_GUESS
772 int qsort_break_even;
773 int swapped;
774#endif
775
7918f24d
NC
776 PERL_ARGS_ASSERT_QSORTSVU;
777
84d4ea48
JH
778 /* Make sure we actually have work to do.
779 */
780 if (num_elts <= 1) {
781 return;
782 }
783
486ec47a 784 /* Inoculate large partitions against quadratic behavior */
4eb872f6 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
dcae3e36 1294 * using their address in the list1 array, ensuring stability.
84d4ea48
JH
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
31e9e0a3 1320cmpindir(pTHX_ gptr const a, gptr const b)
84d4ea48 1321{
97aff369 1322 dVAR;
901017d6
AL
1323 gptr * const ap = (gptr *)a;
1324 gptr * const bp = (gptr *)b;
0bcc34c2 1325 const I32 sense = PL_sort_RealCmp(aTHX_ *ap, *bp);
84d4ea48 1326
0bcc34c2
AL
1327 if (sense)
1328 return sense;
1329 return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
84d4ea48
JH
1330}
1331
6c3fb703 1332static I32
31e9e0a3 1333cmpindir_desc(pTHX_ gptr const a, gptr const b)
6c3fb703 1334{
97aff369 1335 dVAR;
901017d6
AL
1336 gptr * const ap = (gptr *)a;
1337 gptr * const bp = (gptr *)b;
0bcc34c2 1338 const I32 sense = PL_sort_RealCmp(aTHX_ *ap, *bp);
6c3fb703
NC
1339
1340 /* Reverse the default */
0bcc34c2 1341 if (sense)
6c3fb703
NC
1342 return -sense;
1343 /* But don't reverse the stability test. */
1344 return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1345
1346}
1347
84d4ea48 1348STATIC void
6c3fb703 1349S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
84d4ea48 1350{
97aff369 1351 dVAR;
7b9ef140 1352 if ((flags & SORTf_STABLE) != 0) {
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;
a02a5408 1361 else { Newx(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 */
fe2ae508
AL
1370 if (flags & SORTf_DESC)
1371 qsortsvu((gptr *)indir, nmemb, cmpindir_desc);
1372 else
1373 qsortsvu((gptr *)indir, nmemb, cmpindir);
4eb872f6 1374
84d4ea48
JH
1375 pp = indir;
1376 q = list1;
1377 for (n = nmemb; n--; ) {
1378 /* Assert A: all elements of q with index > n are already
486ec47a 1379 * in place. This is vacuously true at the start, and we
84d4ea48
JH
1380 * put element n where it belongs below (if it wasn't
1381 * already where it belonged). Assert B: we only move
1382 * elements that aren't where they belong,
1383 * so, by A, we never tamper with elements above n.
1384 */
1385 j = pp[n] - q; /* This sets j so that q[j] is
1386 * at pp[n]. *pp[j] belongs in
1387 * q[j], by construction.
1388 */
1389 if (n != j) { /* all's well if n == j */
1390 tmp = q[j]; /* save what's in q[j] */
1391 do {
1392 q[j] = *pp[j]; /* put *pp[j] where it belongs */
1393 i = pp[j] - q; /* the index in q of the element
1394 * just moved */
1395 pp[j] = q + j; /* this is ok now */
1396 } while ((j = i) != n);
1397 /* There are only finitely many (nmemb) addresses
1398 * in the pp array.
1399 * So we must eventually revisit an index we saw before.
1400 * Suppose the first revisited index is k != n.
1401 * An index is visited because something else belongs there.
1402 * If we visit k twice, then two different elements must
1403 * belong in the same place, which cannot be.
1404 * So j must get back to n, the loop terminates,
1405 * and we put the saved element where it belongs.
1406 */
1407 q[n] = tmp; /* put what belongs into
1408 * the n-th element */
1409 }
1410 }
1411
1412 /* free iff allocated */
1413 if (indir != small) { Safefree(indir); }
1414 /* restore prevailing comparison routine */
147f47de 1415 PL_sort_RealCmp = savecmp;
7b9ef140 1416 } else if ((flags & SORTf_DESC) != 0) {
d4c19fe8 1417 const SVCOMPARE_t savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
6c3fb703
NC
1418 PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */
1419 cmp = cmp_desc;
fe2ae508 1420 qsortsvu(list1, nmemb, cmp);
6c3fb703
NC
1421 /* restore prevailing comparison routine */
1422 PL_sort_RealCmp = savecmp;
c53fc8a6 1423 } else {
fe2ae508 1424 qsortsvu(list1, nmemb, cmp);
84d4ea48
JH
1425 }
1426}
4eb872f6
JL
1427
1428/*
ccfc67b7
JH
1429=head1 Array Manipulation Functions
1430
84d4ea48
JH
1431=for apidoc sortsv
1432
1433Sort an array. Here is an example:
1434
4eb872f6 1435 sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);
84d4ea48 1436
7b9ef140
RH
1437Currently this always uses mergesort. See sortsv_flags for a more
1438flexible routine.
78210658 1439
84d4ea48
JH
1440=cut
1441*/
4eb872f6 1442
84d4ea48
JH
1443void
1444Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1445{
7918f24d
NC
1446 PERL_ARGS_ASSERT_SORTSV;
1447
7b9ef140 1448 sortsv_flags(array, nmemb, cmp, 0);
6c3fb703
NC
1449}
1450
7b9ef140
RH
1451/*
1452=for apidoc sortsv_flags
6c3fb703 1453
7b9ef140
RH
1454Sort an array, with various options.
1455
1456=cut
1457*/
1458void
1459Perl_sortsv_flags(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
6c3fb703 1460{
7918f24d
NC
1461 PERL_ARGS_ASSERT_SORTSV_FLAGS;
1462
d4c19fe8
AL
1463 if (flags & SORTf_QSORT)
1464 S_qsortsv(aTHX_ array, nmemb, cmp, flags);
1465 else
1466 S_mergesortsv(aTHX_ array, nmemb, cmp, flags);
84d4ea48
JH
1467}
1468
4d562308
SF
1469#define SvNSIOK(sv) ((SvFLAGS(sv) & SVf_NOK) || ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK))
1470#define SvSIOK(sv) ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK)
1471#define SvNSIV(sv) ( SvNOK(sv) ? SvNVX(sv) : ( SvSIOK(sv) ? SvIVX(sv) : sv_2nv(sv) ) )
1472
84d4ea48
JH
1473PP(pp_sort)
1474{
27da23d5 1475 dVAR; dSP; dMARK; dORIGMARK;
fe1bc4cf
DM
1476 register SV **p1 = ORIGMARK+1, **p2;
1477 register I32 max, i;
7d49f689 1478 AV* av = NULL;
84d4ea48
JH
1479 HV *stash;
1480 GV *gv;
cbbf8932 1481 CV *cv = NULL;
84d4ea48 1482 I32 gimme = GIMME;
0bcc34c2 1483 OP* const nextop = PL_op->op_next;
84d4ea48
JH
1484 I32 overloading = 0;
1485 bool hasargs = FALSE;
1486 I32 is_xsub = 0;
fe1bc4cf 1487 I32 sorting_av = 0;
901017d6
AL
1488 const U8 priv = PL_op->op_private;
1489 const U8 flags = PL_op->op_flags;
7b9ef140
RH
1490 U32 sort_flags = 0;
1491 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
1492 = Perl_sortsv_flags;
4d562308 1493 I32 all_SIVs = 1;
84d4ea48 1494
7b9ef140
RH
1495 if ((priv & OPpSORT_DESCEND) != 0)
1496 sort_flags |= SORTf_DESC;
1497 if ((priv & OPpSORT_QSORT) != 0)
1498 sort_flags |= SORTf_QSORT;
1499 if ((priv & OPpSORT_STABLE) != 0)
1500 sort_flags |= SORTf_STABLE;
1501
84d4ea48
JH
1502 if (gimme != G_ARRAY) {
1503 SP = MARK;
b59aed67 1504 EXTEND(SP,1);
84d4ea48
JH
1505 RETPUSHUNDEF;
1506 }
1507
1508 ENTER;
1509 SAVEVPTR(PL_sortcop);
471178c0
NC
1510 if (flags & OPf_STACKED) {
1511 if (flags & OPf_SPECIAL) {
84d4ea48
JH
1512 OP *kid = cLISTOP->op_first->op_sibling; /* pass pushmark */
1513 kid = kUNOP->op_first; /* pass rv2gv */
1514 kid = kUNOP->op_first; /* pass leave */
1515 PL_sortcop = kid->op_next;
1516 stash = CopSTASH(PL_curcop);
1517 }
1518 else {
f7bc00ea
FC
1519 GV *autogv = NULL;
1520 cv = sv_2cv(*++MARK, &stash, &gv, GV_ADD);
1521 check_cv:
84d4ea48 1522 if (cv && SvPOK(cv)) {
ad64d0ec 1523 const char * const proto = SvPV_nolen_const(MUTABLE_SV(cv));
84d4ea48
JH
1524 if (proto && strEQ(proto, "$$")) {
1525 hasargs = TRUE;
1526 }
1527 }
2fc49ef1
FC
1528 if (cv && CvISXSUB(cv) && CvXSUB(cv)) {
1529 is_xsub = 1;
1530 }
1531 else if (!(cv && CvROOT(cv))) {
1532 if (gv) {
f7bc00ea
FC
1533 goto autoload;
1534 }
1535 else if (!CvANON(cv) && (gv = CvGV(cv))) {
1536 if (cv != GvCV(gv)) cv = GvCV(gv);
1537 autoload:
1538 if (!autogv && (
1539 autogv = gv_autoload_pvn(
1540 GvSTASH(gv), GvNAME(gv), GvNAMELEN(gv),
1541 GvNAMEUTF8(gv) ? SVf_UTF8 : 0
1542 )
1543 )) {
1544 cv = GvCVu(autogv);
1545 goto check_cv;
1546 }
1547 else {
84d4ea48 1548 SV *tmpstr = sv_newmortal();
bd61b366 1549 gv_efullname3(tmpstr, gv, NULL);
35c1215d 1550 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called",
be2597df 1551 SVfARG(tmpstr));
f7bc00ea 1552 }
84d4ea48
JH
1553 }
1554 else {
1555 DIE(aTHX_ "Undefined subroutine in sort");
1556 }
1557 }
1558
1559 if (is_xsub)
1560 PL_sortcop = (OP*)cv;
9850bf21 1561 else
84d4ea48 1562 PL_sortcop = CvSTART(cv);
84d4ea48
JH
1563 }
1564 }
1565 else {
5f66b61c 1566 PL_sortcop = NULL;
84d4ea48
JH
1567 stash = CopSTASH(PL_curcop);
1568 }
1569
fe1bc4cf
DM
1570 /* optimiser converts "@a = sort @a" to "sort \@a";
1571 * in case of tied @a, pessimise: push (@a) onto stack, then assign
1572 * result back to @a at the end of this function */
0723351e 1573 if (priv & OPpSORT_INPLACE) {
fe1bc4cf
DM
1574 assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV);
1575 (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */
502c6561 1576 av = MUTABLE_AV((*SP));
fe1bc4cf
DM
1577 max = AvFILL(av) + 1;
1578 if (SvMAGICAL(av)) {
1579 MEXTEND(SP, max);
fe2774ed 1580 for (i=0; i < max; i++) {
fe1bc4cf 1581 SV **svp = av_fetch(av, i, FALSE);
a0714e2c 1582 *SP++ = (svp) ? *svp : NULL;
fe1bc4cf 1583 }
62b40d24
DM
1584 SP--;
1585 p1 = p2 = SP - (max-1);
fe1bc4cf
DM
1586 }
1587 else {
9850bf21 1588 if (SvREADONLY(av))
6ad8f254 1589 Perl_croak_no_modify(aTHX);
9850bf21
RH
1590 else
1591 SvREADONLY_on(av);
fe1bc4cf
DM
1592 p1 = p2 = AvARRAY(av);
1593 sorting_av = 1;
1594 }
1595 }
1596 else {
1597 p2 = MARK+1;
1598 max = SP - MARK;
1599 }
1600
83a44efe
SF
1601 /* shuffle stack down, removing optional initial cv (p1!=p2), plus
1602 * any nulls; also stringify or converting to integer or number as
1603 * required any args */
fe1bc4cf
DM
1604 for (i=max; i > 0 ; i--) {
1605 if ((*p1 = *p2++)) { /* Weed out nulls. */
1606 SvTEMP_off(*p1);
83a44efe
SF
1607 if (!PL_sortcop) {
1608 if (priv & OPpSORT_NUMERIC) {
1609 if (priv & OPpSORT_INTEGER) {
bdbefedf
DM
1610 if (!SvIOK(*p1))
1611 (void)sv_2iv_flags(*p1, SV_GMAGIC|SV_SKIP_OVERLOAD);
83a44efe
SF
1612 }
1613 else {
bdbefedf
DM
1614 if (!SvNSIOK(*p1))
1615 (void)sv_2nv_flags(*p1, SV_GMAGIC|SV_SKIP_OVERLOAD);
4d562308
SF
1616 if (all_SIVs && !SvSIOK(*p1))
1617 all_SIVs = 0;
83a44efe
SF
1618 }
1619 }
1620 else {
bdbefedf
DM
1621 if (!SvPOK(*p1))
1622 (void)sv_2pv_flags(*p1, 0,
1623 SV_GMAGIC|SV_CONST_RETURN|SV_SKIP_OVERLOAD);
83a44efe 1624 }
bdbefedf
DM
1625 if (SvAMAGIC(*p1))
1626 overloading = 1;
84d4ea48 1627 }
fe1bc4cf 1628 p1++;
84d4ea48 1629 }
fe1bc4cf
DM
1630 else
1631 max--;
84d4ea48 1632 }
fe1bc4cf
DM
1633 if (sorting_av)
1634 AvFILLp(av) = max-1;
1635
1636 if (max > 1) {
471178c0 1637 SV **start;
fe1bc4cf 1638 if (PL_sortcop) {
84d4ea48
JH
1639 PERL_CONTEXT *cx;
1640 SV** newsp;
901017d6 1641 const bool oldcatch = CATCH_GET;
84d4ea48
JH
1642
1643 SAVETMPS;
1644 SAVEOP();
1645
1646 CATCH_SET(TRUE);
1647 PUSHSTACKi(PERLSI_SORT);
1648 if (!hasargs && !is_xsub) {
9850bf21
RH
1649 SAVESPTR(PL_firstgv);
1650 SAVESPTR(PL_secondgv);
1651 SAVESPTR(PL_sortstash);
fafc274c
NC
1652 PL_firstgv = gv_fetchpvs("a", GV_ADD|GV_NOTQUAL, SVt_PV);
1653 PL_secondgv = gv_fetchpvs("b", GV_ADD|GV_NOTQUAL, SVt_PV);
9850bf21 1654 PL_sortstash = stash;
84d4ea48
JH
1655 SAVESPTR(GvSV(PL_firstgv));
1656 SAVESPTR(GvSV(PL_secondgv));
1657 }
1658
1659 PUSHBLOCK(cx, CXt_NULL, PL_stack_base);
471178c0 1660 if (!(flags & OPf_SPECIAL)) {
84d4ea48
JH
1661 cx->cx_type = CXt_SUB;
1662 cx->blk_gimme = G_SCALAR;
8a27a13e
FC
1663 /* If our comparison routine is already active (CvDEPTH is
1664 * is not 0), then PUSHSUB does not increase the refcount,
1665 * so we have to do it ourselves, because the LEAVESUB fur-
1666 * ther down lowers it. */
1667 if (CvDEPTH(cv)) SvREFCNT_inc_simple_void_NN(cv);
84d4ea48 1668 PUSHSUB(cx);
9850bf21 1669 if (!is_xsub) {
0bcc34c2 1670 AV* const padlist = CvPADLIST(cv);
9850bf21
RH
1671
1672 if (++CvDEPTH(cv) >= 2) {
1673 PERL_STACK_OVERFLOW_CHECK();
1674 pad_push(padlist, CvDEPTH(cv));
1675 }
1676 SAVECOMPPAD();
1677 PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));
84d4ea48 1678
9850bf21
RH
1679 if (hasargs) {
1680 /* This is mostly copied from pp_entersub */
502c6561 1681 AV * const av = MUTABLE_AV(PAD_SVl(0));
84d4ea48 1682
9850bf21 1683 cx->blk_sub.savearray = GvAV(PL_defgv);
502c6561 1684 GvAV(PL_defgv) = MUTABLE_AV(SvREFCNT_inc_simple(av));
9850bf21
RH
1685 CX_CURPAD_SAVE(cx->blk_sub);
1686 cx->blk_sub.argarray = av;
1687 }
1688
1689 }
84d4ea48 1690 }
9850bf21 1691 cx->cx_type |= CXp_MULTICALL;
471178c0
NC
1692
1693 start = p1 - max;
1694 sortsvp(aTHX_ start, max,
7b9ef140
RH
1695 (is_xsub ? S_sortcv_xsub : hasargs ? S_sortcv_stacked : S_sortcv),
1696 sort_flags);
84d4ea48 1697
9850bf21 1698 if (!(flags & OPf_SPECIAL)) {
133acf7b 1699 SV *sv;
8e7d0c4b
FC
1700 /* Reset cx, in case the context stack has been
1701 reallocated. */
1702 cx = &cxstack[cxstack_ix];
133acf7b
NC
1703 POPSUB(cx, sv);
1704 LEAVESUB(sv);
9850bf21 1705 }
84d4ea48
JH
1706 POPBLOCK(cx,PL_curpm);
1707 PL_stack_sp = newsp;
1708 POPSTACK;
1709 CATCH_SET(oldcatch);
1710 }
fe1bc4cf 1711 else {
84d4ea48 1712 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */
471178c0
NC
1713 start = sorting_av ? AvARRAY(av) : ORIGMARK+1;
1714 sortsvp(aTHX_ start, max,
0723351e 1715 (priv & OPpSORT_NUMERIC)
4d562308 1716 ? ( ( ( priv & OPpSORT_INTEGER) || all_SIVs)
f0f5dc9d
AL
1717 ? ( overloading ? S_amagic_i_ncmp : S_sv_i_ncmp)
1718 : ( overloading ? S_amagic_ncmp : S_sv_ncmp ) )
84d4ea48
JH
1719 : ( IN_LOCALE_RUNTIME
1720 ? ( overloading
d3fcec1f
SP
1721 ? (SVCOMPARE_t)S_amagic_cmp_locale
1722 : (SVCOMPARE_t)sv_cmp_locale_static)
1723 : ( overloading ? (SVCOMPARE_t)S_amagic_cmp : (SVCOMPARE_t)sv_cmp_static)),
7b9ef140 1724 sort_flags);
471178c0 1725 }
7b9ef140 1726 if ((priv & OPpSORT_REVERSE) != 0) {
471178c0
NC
1727 SV **q = start+max-1;
1728 while (start < q) {
0bcc34c2 1729 SV * const tmp = *start;
471178c0
NC
1730 *start++ = *q;
1731 *q-- = tmp;
84d4ea48
JH
1732 }
1733 }
1734 }
9850bf21
RH
1735 if (sorting_av)
1736 SvREADONLY_off(av);
1737 else if (av && !sorting_av) {
fe1bc4cf 1738 /* simulate pp_aassign of tied AV */
62b40d24 1739 SV** const base = MARK+1;
901017d6
AL
1740 for (i=0; i < max; i++) {
1741 base[i] = newSVsv(base[i]);
fe1bc4cf
DM
1742 }
1743 av_clear(av);
1744 av_extend(av, max);
1745 for (i=0; i < max; i++) {
901017d6 1746 SV * const sv = base[i];
551405c4 1747 SV ** const didstore = av_store(av, i, sv);
fe1bc4cf
DM
1748 if (SvSMAGICAL(sv))
1749 mg_set(sv);
1750 if (!didstore)
1751 sv_2mortal(sv);
1752 }
1753 }
84d4ea48 1754 LEAVE;
fe1bc4cf 1755 PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max);
84d4ea48
JH
1756 return nextop;
1757}
1758
1759static I32
31e9e0a3 1760S_sortcv(pTHX_ SV *const a, SV *const b)
84d4ea48 1761{
27da23d5 1762 dVAR;
901017d6
AL
1763 const I32 oldsaveix = PL_savestack_ix;
1764 const I32 oldscopeix = PL_scopestack_ix;
84d4ea48 1765 I32 result;
ad021bfb 1766 PMOP * const pm = PL_curpm;
d4c6760a 1767 OP * const sortop = PL_op;
a9ea019a 1768 COP * const cop = PL_curcop;
1aa032b2 1769 SV **pad;
7918f24d
NC
1770
1771 PERL_ARGS_ASSERT_SORTCV;
1772
84d4ea48
JH
1773 GvSV(PL_firstgv) = a;
1774 GvSV(PL_secondgv) = b;
1775 PL_stack_sp = PL_stack_base;
1776 PL_op = PL_sortcop;
1777 CALLRUNOPS(aTHX);
d4c6760a 1778 PL_op = sortop;
a9ea019a 1779 PL_curcop = cop;
1aa032b2 1780 pad = PL_curpad; PL_curpad = 0;
1715fa64
FC
1781 if (PL_stack_sp != PL_stack_base + 1) {
1782 assert(PL_stack_sp == PL_stack_base);
1783 result = SvIV(&PL_sv_undef);
1784 }
1785 else result = SvIV(*PL_stack_sp);
1aa032b2 1786 PL_curpad = pad;
84d4ea48
JH
1787 while (PL_scopestack_ix > oldscopeix) {
1788 LEAVE;
1789 }
1790 leave_scope(oldsaveix);
ad021bfb 1791 PL_curpm = pm;
84d4ea48
JH
1792 return result;
1793}
1794
1795static I32
31e9e0a3 1796S_sortcv_stacked(pTHX_ SV *const a, SV *const b)
84d4ea48 1797{
27da23d5 1798 dVAR;
901017d6
AL
1799 const I32 oldsaveix = PL_savestack_ix;
1800 const I32 oldscopeix = PL_scopestack_ix;
84d4ea48 1801 I32 result;
901017d6 1802 AV * const av = GvAV(PL_defgv);
ad021bfb 1803 PMOP * const pm = PL_curpm;
d4c6760a 1804 OP * const sortop = PL_op;
a9ea019a 1805 COP * const cop = PL_curcop;
1aa032b2 1806 SV **pad;
84d4ea48 1807
7918f24d
NC
1808 PERL_ARGS_ASSERT_SORTCV_STACKED;
1809
8f443ca6
GG
1810 if (AvREAL(av)) {
1811 av_clear(av);
1812 AvREAL_off(av);
1813 AvREIFY_on(av);
1814 }
84d4ea48 1815 if (AvMAX(av) < 1) {
8f443ca6 1816 SV **ary = AvALLOC(av);
84d4ea48
JH
1817 if (AvARRAY(av) != ary) {
1818 AvMAX(av) += AvARRAY(av) - AvALLOC(av);
9c6bc640 1819 AvARRAY(av) = ary;
84d4ea48
JH
1820 }
1821 if (AvMAX(av) < 1) {
1822 AvMAX(av) = 1;
1823 Renew(ary,2,SV*);
9c6bc640 1824 AvARRAY(av) = ary;
8f443ca6 1825 AvALLOC(av) = ary;
84d4ea48
JH
1826 }
1827 }
1828 AvFILLp(av) = 1;
1829
1830 AvARRAY(av)[0] = a;
1831 AvARRAY(av)[1] = b;
1832 PL_stack_sp = PL_stack_base;
1833 PL_op = PL_sortcop;
1834 CALLRUNOPS(aTHX);
d4c6760a 1835 PL_op = sortop;
a9ea019a 1836 PL_curcop = cop;
1aa032b2 1837 pad = PL_curpad; PL_curpad = 0;
1715fa64
FC
1838 if (PL_stack_sp != PL_stack_base + 1) {
1839 assert(PL_stack_sp == PL_stack_base);
1840 result = SvIV(&PL_sv_undef);
1841 }
1842 else result = SvIV(*PL_stack_sp);
1aa032b2 1843 PL_curpad = pad;
84d4ea48
JH
1844 while (PL_scopestack_ix > oldscopeix) {
1845 LEAVE;
1846 }
1847 leave_scope(oldsaveix);
ad021bfb 1848 PL_curpm = pm;
84d4ea48
JH
1849 return result;
1850}
1851
1852static I32
31e9e0a3 1853S_sortcv_xsub(pTHX_ SV *const a, SV *const b)
84d4ea48 1854{
27da23d5 1855 dVAR; dSP;
901017d6
AL
1856 const I32 oldsaveix = PL_savestack_ix;
1857 const I32 oldscopeix = PL_scopestack_ix;
ea726b52 1858 CV * const cv=MUTABLE_CV(PL_sortcop);
84d4ea48 1859 I32 result;
ad021bfb 1860 PMOP * const pm = PL_curpm;
84d4ea48 1861
7918f24d
NC
1862 PERL_ARGS_ASSERT_SORTCV_XSUB;
1863
84d4ea48
JH
1864 SP = PL_stack_base;
1865 PUSHMARK(SP);
1866 EXTEND(SP, 2);
1867 *++SP = a;
1868 *++SP = b;
1869 PUTBACK;
1870 (void)(*CvXSUB(cv))(aTHX_ cv);
1871 if (PL_stack_sp != PL_stack_base + 1)
1872 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
84d4ea48
JH
1873 result = SvIV(*PL_stack_sp);
1874 while (PL_scopestack_ix > oldscopeix) {
1875 LEAVE;
1876 }
1877 leave_scope(oldsaveix);
ad021bfb 1878 PL_curpm = pm;
84d4ea48
JH
1879 return result;
1880}
1881
1882
1883static I32
31e9e0a3 1884S_sv_ncmp(pTHX_ SV *const a, SV *const b)
84d4ea48 1885{
901017d6
AL
1886 const NV nv1 = SvNSIV(a);
1887 const NV nv2 = SvNSIV(b);
7918f24d
NC
1888
1889 PERL_ARGS_ASSERT_SV_NCMP;
1890
f3dab52a 1891#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
324e9a83 1892 if (Perl_isnan(nv1) || Perl_isnan(nv2)) {
f3dab52a
FC
1893#else
1894 if (nv1 != nv1 || nv2 != nv2) {
1895#endif
1896 if (ckWARN(WARN_UNINITIALIZED)) report_uninit(NULL);
1897 return 0;
1898 }
84d4ea48
JH
1899 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0;
1900}
1901
1902static I32
31e9e0a3 1903S_sv_i_ncmp(pTHX_ SV *const a, SV *const b)
84d4ea48 1904{
901017d6
AL
1905 const IV iv1 = SvIV(a);
1906 const IV iv2 = SvIV(b);
7918f24d
NC
1907
1908 PERL_ARGS_ASSERT_SV_I_NCMP;
1909
84d4ea48
JH
1910 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0;
1911}
901017d6
AL
1912
1913#define tryCALL_AMAGICbin(left,right,meth) \
79a8d529 1914 (SvAMAGIC(left)||SvAMAGIC(right)) \
31d632c3 1915 ? amagic_call(left, right, meth, 0) \
a0714e2c 1916 : NULL;
84d4ea48 1917
eeb9de02
ST
1918#define SORT_NORMAL_RETURN_VALUE(val) (((val) > 0) ? 1 : ((val) ? -1 : 0))
1919
84d4ea48 1920static I32
31e9e0a3 1921S_amagic_ncmp(pTHX_ register SV *const a, register SV *const b)
84d4ea48 1922{
97aff369 1923 dVAR;
31d632c3 1924 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp_amg);
7918f24d
NC
1925
1926 PERL_ARGS_ASSERT_AMAGIC_NCMP;
1927
84d4ea48 1928 if (tmpsv) {
84d4ea48 1929 if (SvIOK(tmpsv)) {
901017d6 1930 const I32 i = SvIVX(tmpsv);
eeb9de02 1931 return SORT_NORMAL_RETURN_VALUE(i);
84d4ea48 1932 }
901017d6
AL
1933 else {
1934 const NV d = SvNV(tmpsv);
eeb9de02 1935 return SORT_NORMAL_RETURN_VALUE(d);
901017d6 1936 }
84d4ea48 1937 }
f0f5dc9d 1938 return S_sv_ncmp(aTHX_ a, b);
84d4ea48
JH
1939}
1940
1941static I32
31e9e0a3 1942S_amagic_i_ncmp(pTHX_ register SV *const a, register SV *const b)
84d4ea48 1943{
97aff369 1944 dVAR;
31d632c3 1945 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp_amg);
7918f24d
NC
1946
1947 PERL_ARGS_ASSERT_AMAGIC_I_NCMP;
1948
84d4ea48 1949 if (tmpsv) {
84d4ea48 1950 if (SvIOK(tmpsv)) {
901017d6 1951 const I32 i = SvIVX(tmpsv);
eeb9de02 1952 return SORT_NORMAL_RETURN_VALUE(i);
84d4ea48 1953 }
901017d6
AL
1954 else {
1955 const NV d = SvNV(tmpsv);
eeb9de02 1956 return SORT_NORMAL_RETURN_VALUE(d);
901017d6 1957 }
84d4ea48 1958 }
f0f5dc9d 1959 return S_sv_i_ncmp(aTHX_ a, b);
84d4ea48
JH
1960}
1961
1962static I32
31e9e0a3 1963S_amagic_cmp(pTHX_ register SV *const str1, register SV *const str2)
84d4ea48 1964{
97aff369 1965 dVAR;
31d632c3 1966 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp_amg);
7918f24d
NC
1967
1968 PERL_ARGS_ASSERT_AMAGIC_CMP;
1969
84d4ea48 1970 if (tmpsv) {
84d4ea48 1971 if (SvIOK(tmpsv)) {
901017d6 1972 const I32 i = SvIVX(tmpsv);
eeb9de02 1973 return SORT_NORMAL_RETURN_VALUE(i);
84d4ea48 1974 }
901017d6
AL
1975 else {
1976 const NV d = SvNV(tmpsv);
eeb9de02 1977 return SORT_NORMAL_RETURN_VALUE(d);
901017d6 1978 }
84d4ea48
JH
1979 }
1980 return sv_cmp(str1, str2);
1981}
1982
1983static I32
31e9e0a3 1984S_amagic_cmp_locale(pTHX_ register SV *const str1, register SV *const str2)
84d4ea48 1985{
97aff369 1986 dVAR;
31d632c3 1987 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp_amg);
7918f24d
NC
1988
1989 PERL_ARGS_ASSERT_AMAGIC_CMP_LOCALE;
1990
84d4ea48 1991 if (tmpsv) {
84d4ea48 1992 if (SvIOK(tmpsv)) {
901017d6 1993 const I32 i = SvIVX(tmpsv);
eeb9de02 1994 return SORT_NORMAL_RETURN_VALUE(i);
84d4ea48 1995 }
901017d6
AL
1996 else {
1997 const NV d = SvNV(tmpsv);
eeb9de02 1998 return SORT_NORMAL_RETURN_VALUE(d);
901017d6 1999 }
84d4ea48
JH
2000 }
2001 return sv_cmp_locale(str1, str2);
2002}
241d1a3b
NC
2003
2004/*
2005 * Local variables:
2006 * c-indentation-style: bsd
2007 * c-basic-offset: 4
2008 * indent-tabs-mode: t
2009 * End:
2010 *
37442d52
RGS
2011 * ex: set ts=8 sts=4 sw=4 noet:
2012 */