3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 * 2000, 2001, 2002, 2003, 2004, 2005, by Larry Wall and others
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.
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...
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.
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
28 #define PERL_IN_PP_SORT_C
32 /* looks like 'small' is reserved word for WINCE (or somesuch)*/
36 static I32 sortcv(pTHX_ SV *a, SV *b);
37 static I32 sortcv_stacked(pTHX_ SV *a, SV *b);
38 static I32 sortcv_xsub(pTHX_ SV *a, SV *b);
39 static I32 sv_ncmp(pTHX_ SV *a, SV *b);
40 static I32 sv_i_ncmp(pTHX_ SV *a, SV *b);
41 static I32 amagic_ncmp(pTHX_ SV *a, SV *b);
42 static I32 amagic_i_ncmp(pTHX_ SV *a, SV *b);
43 static I32 amagic_cmp(pTHX_ SV *a, SV *b);
44 static I32 amagic_cmp_locale(pTHX_ SV *a, SV *b);
46 #define sv_cmp_static Perl_sv_cmp
47 #define sv_cmp_locale_static Perl_sv_cmp_locale
49 #define dSORTHINTS SV *hintsv = GvSV(gv_fetchpv("sort::hints", GV_ADDMULTI, SVt_IV))
50 #define SORTHINTS (SvIOK(hintsv) ? ((I32)SvIV(hintsv)) : 0)
53 #define SMALLSORT (200)
57 * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>.
59 * The original code was written in conjunction with BSD Computer Software
60 * Research Group at University of California, Berkeley.
62 * See also: "Optimistic Merge Sort" (SODA '92)
64 * The integration to Perl is by John P. Linderman <jpl@research.att.com>.
66 * The code can be distributed under the same terms as Perl itself.
71 typedef char * aptr; /* pointer for arithmetic on sizes */
72 typedef SV * gptr; /* pointers in our lists */
74 /* Binary merge internal sort, with a few special mods
75 ** for the special perl environment it now finds itself in.
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.
83 /* Pointer types for arithmetic and storage and convenience casts */
85 #define APTR(P) ((aptr)(P))
86 #define GPTP(P) ((gptr *)(P))
87 #define GPPP(P) ((gptr **)(P))
90 /* byte offset from pointer P to (larger) pointer Q */
91 #define BYTEOFF(P, Q) (APTR(Q) - APTR(P))
93 #define PSIZE sizeof(gptr)
95 /* If PSIZE is power of 2, make PSHIFT that power, if that helps */
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)))
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))
108 /* Pointer into other corresponding to pointer into this */
109 #define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P))
111 #define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim)
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.
120 #define NEXT(P) (*GPPP(P))
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.
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.
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.
147 ** Unless otherwise specified, pair pointers address the first of two elements.
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.
152 ** p2 parallels b in the list2 array, where runs are defined by
155 ** t represents the "top" of the adjacent pairs that might extend
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,
159 ** or it may be equal to "last", the first element beyond list1.
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.
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.
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.
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
181 ** 2) Long run. b < r <= q < t.
182 ** b through q is a run (of length >= 2 * PTHRESH)
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.
191 dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, SVCOMPARE_t cmp)
194 register gptr *b, *p, *q, *t, *p2;
195 register gptr c, *last, *r;
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.
206 for (p = b+2, t = p; ++p < last; t = ++p) {
207 if ((cmp(aTHX_ *t, *p) > 0) != sense) break;
210 /* Having laid out the playing field, look for long runs */
212 p = r = b + (2 * PTHRESH);
213 if (r >= t) p = r = t; /* too short to care about */
215 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) &&
218 /* b through r is a (long) run.
219 ** Extend it as far as possible.
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 */
227 if (q > b) { /* run of greater than 2 at b */
230 /* pick up singleton, if possible */
233 ((cmp(aTHX_ *(p-1), *p) > 0) == sense))
234 savep = r = p = q = last;
235 p2 = NEXT(p2) = p2 + (p - b); ++runs;
236 if (sense) while (b < --p) {
243 while (q < p) { /* simple pairs */
244 p2 = NEXT(p2) = p2 + 2; ++runs;
251 if (((b = p) == t) && ((t+1) == last)) {
252 NEXT(p2) = p2 + 1; ++runs;
263 /* The original merge sort, in use since 5.7, was as fast as, or faster than,
264 * qsort on many platforms, but slower than qsort, conspicuously so,
265 * on others. The most likely explanation was platform-specific
266 * differences in cache sizes and relative speeds.
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.
274 * By contrast, consider how the original mergesort algorithm worked.
275 * Suppose we have five runs (each typically of length 2 after dynprep).
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.
290 * The following pseudo-code uses the same basic merge algorithm,
291 * but in a divide-and-conquer way.
293 * # merge $runs runs at offset $offset of list $list1 into $list2.
294 * # all unmerged runs ($runs == 1) originate in list $base.
296 * my ($offset, $runs, $base, $list1, $list2) = @_;
299 * if ($list1 is $base) copy run to $list2
300 * return offset of end of list (or copy)
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
308 * mgsort2(0, $runs, $base, $aux, $base);
310 * For our 5 runs, the tree of calls looks like
319 * and the corresponding activity looks like
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
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).
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.
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 */
350 cmp_desc(pTHX_ gptr a, gptr b)
352 return -PL_sort_RealCmp(aTHX_ a, b);
356 S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
358 IV i, run, runs, offset;
361 register gptr *f1, *f2, *t, *b, *p, *tp2, *l1, *l2, *q;
362 gptr *aux, *list1, *list2;
364 gptr small[SMALLSORT];
366 off_runs stack[60], *stackp;
367 SVCOMPARE_t savecmp = 0;
369 if (nmemb <= 1) return; /* sorted trivially */
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 */
377 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */
378 else { Newx(aux,nmemb,gptr); } /* allocate auxilliary array */
381 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp);
382 stackp->offset = offset = 0;
383 which[0] = which[2] = base;
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.
391 if ((runs = stackp->runs) == 0) {
393 list1 = which[iwhich]; /* area where runs are now */
394 list2 = which[++iwhich]; /* area for merged runs */
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.
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
414 ** if "q is strictly less than the other",
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.
426 if (cmp(aTHX_ *f1, *f2) <= 0) {
427 q = f2; b = f1; t = l1;
430 q = f1; b = f2; t = l2;
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.
441 for (i = 1, run = 0 ;;) {
442 if ((p = PINDEX(b, i)) >= t) {
444 if (((p = PINDEX(t, -1)) > b) &&
445 (cmp(aTHX_ *q, *p) <= sense))
449 } else if (cmp(aTHX_ *q, *p) <= sense) {
453 if (++run >= RTHRESH) i += i;
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.
465 p = PINDEX(b, (PNELEM(b, t) - 1) / 2);
466 if (cmp(aTHX_ *q, *p) <= sense) {
472 /* Copy all the strictly low elements */
475 FROMTOUPTO(f2, tp2, t);
478 FROMTOUPTO(f1, tp2, t);
484 /* Run out remaining list */
486 if (f2 < l2) FROMTOUPTO(f2, tp2, l2);
487 } else FROMTOUPTO(f1, tp2, l1);
488 p1 = NEXT(p1) = POTHER(tp2, list2, list1);
490 if (--level == 0) goto done;
492 t = list1; list1 = list2; list2 = t; /* swap lists */
493 } while ((runs = stackp->runs) == 0);
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.
507 stackp->offset = offset;
508 runs -= stackp->runs = runs / 2;
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].
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.
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 */
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.
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 */
558 if (aux != small) Safefree(aux); /* free iff allocated */
560 PL_sort_RealCmp = savecmp; /* Restore current comparison routine, if any */
566 * The quicksort implementation was derived from source code contributed
569 * NOTE: this code was derived from Tom Horsley's qsort replacement
570 * and should not be confused with the original code.
573 /* Copyright (C) Tom Horsley, 1997. All rights reserved.
575 Permission granted to distribute under the same terms as perl which are
578 This program is free software; you can redistribute it and/or modify
579 it under the terms of either:
581 a) the GNU General Public License as published by the Free
582 Software Foundation; either version 1, or (at your option) any
585 b) the "Artistic License" which comes with this Kit.
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.
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.
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).
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 :-).
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:
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...
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 :-).
614 /* ********************************************************** Configuration */
616 #ifndef QSORT_ORDER_GUESS
617 #define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */
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 :-).
628 #ifndef QSORT_MAX_STACK
629 #define QSORT_MAX_STACK 32
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).
638 #ifndef QSORT_BREAK_EVEN
639 #define QSORT_BREAK_EVEN 6
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.
649 #ifndef QSORT_PLAY_SAFE
650 #define QSORT_PLAY_SAFE 255
653 /* ************************************************************* Data Types */
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
659 struct partition_stack_entry {
662 #ifdef QSORT_ORDER_GUESS
663 int qsort_break_even;
667 /* ******************************************************* Shorthand Macros */
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.
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.
680 /* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2
682 #define qsort_cmp(elt1, elt2) \
683 ((*compare)(aTHX_ array[elt1], array[elt2]))
685 #ifdef QSORT_ORDER_GUESS
686 #define QSORT_NOTICE_SWAP swapped++;
688 #define QSORT_NOTICE_SWAP
691 /* swaps contents of array elements elt1, elt2.
693 #define qsort_swap(elt1, elt2) \
696 temp = array[elt1]; \
697 array[elt1] = array[elt2]; \
698 array[elt2] = temp; \
701 /* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets
702 elt3 and elt3 gets elt1.
704 #define qsort_rotate(elt1, elt2, elt3) \
707 temp = array[elt1]; \
708 array[elt1] = array[elt2]; \
709 array[elt2] = array[elt3]; \
710 array[elt3] = temp; \
713 /* ************************************************************ Debug stuff */
720 return; /* good place to set a breakpoint */
723 #define qsort_assert(t) (void)( (t) || (break_here(), 0) )
730 int (*compare)(const void * elt1, const void * elt2),
731 int pc_left, int pc_right, int u_left, int u_right)
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);
741 for (i = pc_left; i < pc_right; ++i) {
742 qsort_assert(qsort_cmp(i, pc_right) == 0);
744 for (i = pc_right + 1; i < u_left; ++i) {
745 qsort_assert(qsort_cmp(pc_right, i) < 0);
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)
755 #define qsort_assert(t) ((void)0)
757 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0)
761 /* ****************************************************************** qsort */
763 STATIC void /* the standard unstable (u) quicksort (qsort) */
764 S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare)
768 struct partition_stack_entry partition_stack[QSORT_MAX_STACK];
769 int next_stack_entry = 0;
773 #ifdef QSORT_ORDER_GUESS
774 int qsort_break_even;
778 /* Make sure we actually have work to do.
784 /* Innoculate large partitions against quadratic behavior */
785 if (num_elts > QSORT_PLAY_SAFE) {
787 register SV ** const q = array;
788 for (n = num_elts; n > 1; ) {
789 register const size_t j = (size_t)(n-- * Drand01());
796 /* Setup the initial partition definition and fall into the sorting loop
799 part_right = (int)(num_elts - 1);
800 #ifdef QSORT_ORDER_GUESS
801 qsort_break_even = QSORT_BREAK_EVEN;
803 #define qsort_break_even QSORT_BREAK_EVEN
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
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:
815 pc_left - the leftmost array index of the pc
816 pc_right - the rightmost array index of the pc
818 we start with pc_left == pc_right and only one element
819 in the pivot chunk (but it can grow during the scan).
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.
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
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
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.
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).
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
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
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.
864 int pc_left, pc_right;
869 pc_left = ((part_left + part_right) / 2);
871 u_right = pc_left - 1;
872 u_left = pc_right + 1;
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.
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
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.
899 #ifdef QSORT_ORDER_GUESS
902 s = qsort_cmp(u_right, pc_left);
905 s = qsort_cmp(pc_left, u_left);
906 /* if l < c, c < r - already in order - nothing to do */
908 /* l < c, c == r - already in order, pc grows */
910 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
912 /* l < c, c > r - need to know more */
913 s = qsort_cmp(u_right, u_left);
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);
919 /* l < c, c > r, l == r - swap c&r, grow pc */
920 qsort_swap(pc_left, u_left);
922 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
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);
931 s = qsort_cmp(pc_left, u_left);
933 /* l == c, c < r - already in order, grow pc */
935 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
937 /* l == c, c == r - already in order, grow pc both ways */
940 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
942 /* l == c, c > r - swap l & r, grow pc */
943 qsort_swap(u_right, u_left);
945 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
949 s = qsort_cmp(pc_left, u_left);
951 /* l > c, c < r - need to know more */
952 s = qsort_cmp(u_right, u_left);
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);
958 /* l > c, c < r, l == r - swap l & c, grow pc */
959 qsort_swap(u_right, pc_left);
961 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
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);
968 /* l > c, c == r - swap ends, grow pc */
969 qsort_swap(u_right, u_left);
971 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
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);
978 /* We now know the 3 middle elements have been compared and
979 arranged in the desired order, so we can shrink the uncompared
984 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
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.
994 int still_work_on_left;
995 int still_work_on_right;
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.
1004 while ((still_work_on_left = (u_right >= part_left))) {
1005 s = qsort_cmp(u_right, pc_left);
1008 } else if (s == 0) {
1010 if (pc_left != u_right) {
1011 qsort_swap(u_right, pc_left);
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);
1023 /* Do a mirror image scan of uncompared values on the right
1025 while ((still_work_on_right = (u_left <= part_right))) {
1026 s = qsort_cmp(pc_right, u_left);
1029 } else if (s == 0) {
1031 if (pc_right != u_left) {
1032 qsort_swap(pc_right, u_left);
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);
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.
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.
1056 qsort_swap(u_right, u_left);
1059 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
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
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);
1077 qsort_rotate(u_right, pc_left, pc_right);
1078 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
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.
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);
1094 qsort_rotate(pc_right, pc_left, u_left);
1095 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1100 /* No more scanning required on either side of partition,
1101 break out of loop and figure out next set of partitions
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
1112 Notes on the QSORT_ORDER_GUESS ifdef code:
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
1120 2. A (properly written) insertion sort will run faster on
1121 already ordered data than qsort will.
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).
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?
1136 #ifdef QSORT_ORDER_GUESS
1138 #if QSORT_ORDER_GUESS == 1
1139 qsort_break_even = (part_right - part_left) + 1;
1141 #if QSORT_ORDER_GUESS == 2
1142 qsort_break_even *= 2;
1144 #if QSORT_ORDER_GUESS == 3
1145 const int prev_break = qsort_break_even;
1146 qsort_break_even *= qsort_break_even;
1147 if (qsort_break_even < prev_break) {
1148 qsort_break_even = (part_right - part_left) + 1;
1152 qsort_break_even = QSORT_BREAK_EVEN;
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.
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.
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;
1175 part_right = pc_left - 1;
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;
1183 part_left = pc_right + 1;
1185 qsort_assert(next_stack_entry < QSORT_MAX_STACK);
1188 /* The elements on the left are the only remaining elements
1189 that need sorting, arrange for them to be processed as the
1192 part_right = pc_left - 1;
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.
1198 part_left = pc_right + 1;
1200 /* This whole partition wound up in the pivot chunk, so
1201 we need to get a new partition off the stack.
1203 if (next_stack_entry == 0) {
1204 /* the stack is empty - we are done */
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;
1215 /* This partition is too small to fool with qsort complexity, just
1216 do an ordinary insertion sort to minimize overhead.
1219 /* Assume 1st element is in right place already, and start checking
1220 at 2nd element to see where it should be inserted.
1222 for (i = part_left + 1; i <= part_right; ++i) {
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.
1228 for (j = i - 1; j >= part_left; --j) {
1229 if (qsort_cmp(i, j) >= 0) {
1230 /* i belongs right after j
1237 /* Looks like we really need to move some things
1241 for (k = i - 1; k >= j; --k)
1242 array[k + 1] = array[k];
1247 /* That partition is now sorted, grab the next one, or get out
1248 of the loop if there aren't any more.
1251 if (next_stack_entry == 0) {
1252 /* the stack is empty - we are done */
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;
1264 /* Believe it or not, the array is sorted at this point! */
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
1276 * | | --------------> | | ------> first element to be sorted
1278 * | | --------------> | | ------> second element to be sorted
1280 * | | --------------> | | ------> third element to be sorted
1284 * | | --------------> | | ------> n-1st element to be sorted
1286 * | | --------------> | | ------> n-th element to be sorted
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
1299 * | | --+ +---> | | ------> first element to be sorted
1301 * | | --|-------|---> | | ------> second element to be sorted
1303 * | | --|-------+ +-> | | ------> third element to be sorted
1306 * +----+ | | | | +----+
1307 * | | ---|-+ | +--> | | ------> n-1st element to be sorted
1309 * | | ---+ +----> | | ------> n-th element to be sorted
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.
1320 cmpindir(pTHX_ gptr a, gptr b)
1323 gptr * const ap = (gptr *)a;
1324 gptr * const bp = (gptr *)b;
1326 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)) == 0)
1327 sense = (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1332 cmpindir_desc(pTHX_ gptr a, gptr b)
1335 gptr * const ap = (gptr *)a;
1336 gptr * const bp = (gptr *)b;
1338 /* Reverse the default */
1339 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)))
1341 /* But don't reverse the stability test. */
1342 return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1347 S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
1352 if (SORTHINTS & HINT_SORT_STABLE) {
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 */
1359 /* Small arrays can use the stack, big ones must be allocated */
1360 if (nmemb <= SMALLSORT) indir = small;
1361 else { Newx(indir, nmemb, gptr *); }
1363 /* Copy pointers to original array elements into indirect array */
1364 for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++;
1366 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
1367 PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */
1369 /* sort, with indirection */
1370 S_qsortsvu(aTHX_ (gptr *)indir, nmemb,
1371 flags ? cmpindir_desc : cmpindir);
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.
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.
1387 if (n != j) { /* all's well if n == j */
1388 tmp = q[j]; /* save what's in q[j] */
1390 q[j] = *pp[j]; /* put *pp[j] where it belongs */
1391 i = pp[j] - q; /* the index in q of the element
1393 pp[j] = q + j; /* this is ok now */
1394 } while ((j = i) != n);
1395 /* There are only finitely many (nmemb) addresses
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.
1405 q[n] = tmp; /* put what belongs into
1406 * the n-th element */
1410 /* free iff allocated */
1411 if (indir != small) { Safefree(indir); }
1412 /* restore prevailing comparison routine */
1413 PL_sort_RealCmp = savecmp;
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 */
1418 S_qsortsvu(aTHX_ list1, nmemb, cmp);
1419 /* restore prevailing comparison routine */
1420 PL_sort_RealCmp = savecmp;
1422 S_qsortsvu(aTHX_ list1, nmemb, cmp);
1427 =head1 Array Manipulation Functions
1431 Sort an array. Here is an example:
1433 sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);
1435 See lib/sort.pm for details about controlling the sorting algorithm.
1441 Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1443 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
1446 const I32 hints = SORTHINTS;
1447 if (hints & HINT_SORT_QUICKSORT) {
1448 sortsvp = S_qsortsv;
1451 /* The default as of 5.8.0 is mergesort */
1452 sortsvp = S_mergesortsv;
1455 sortsvp(aTHX_ array, nmemb, cmp, 0);
1460 S_sortsv_desc(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1462 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags)
1465 const I32 hints = SORTHINTS;
1466 if (hints & HINT_SORT_QUICKSORT) {
1467 sortsvp = S_qsortsv;
1470 /* The default as of 5.8.0 is mergesort */
1471 sortsvp = S_mergesortsv;
1474 sortsvp(aTHX_ array, nmemb, cmp, 1);
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) ) )
1483 dVAR; dSP; dMARK; dORIGMARK;
1484 register SV **p1 = ORIGMARK+1, **p2;
1485 register I32 max, i;
1491 OP* nextop = PL_op->op_next;
1492 I32 overloading = 0;
1493 bool hasargs = FALSE;
1496 const U8 priv = PL_op->op_private;
1497 const U8 flags = PL_op->op_flags;
1498 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1502 if (gimme != G_ARRAY) {
1508 SAVEVPTR(PL_sortcop);
1509 if (flags & OPf_STACKED) {
1510 if (flags & OPf_SPECIAL) {
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);
1518 cv = sv_2cv(*++MARK, &stash, &gv, 0);
1519 if (cv && SvPOK(cv)) {
1520 const char *proto = SvPV_nolen_const((SV*)cv);
1521 if (proto && strEQ(proto, "$$")) {
1525 if (!(cv && CvROOT(cv))) {
1526 if (cv && CvXSUB(cv)) {
1530 SV *tmpstr = sv_newmortal();
1531 gv_efullname3(tmpstr, gv, Nullch);
1532 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called",
1536 DIE(aTHX_ "Undefined subroutine in sort");
1541 PL_sortcop = (OP*)cv;
1543 PL_sortcop = CvSTART(cv);
1544 SAVEVPTR(CvROOT(cv)->op_ppaddr);
1545 CvROOT(cv)->op_ppaddr = PL_ppaddr[OP_NULL];
1548 PAD_SET_CUR_NOSAVE(CvPADLIST(cv), 1);
1553 PL_sortcop = Nullop;
1554 stash = CopSTASH(PL_curcop);
1557 /* optimiser converts "@a = sort @a" to "sort \@a";
1558 * in case of tied @a, pessimise: push (@a) onto stack, then assign
1559 * result back to @a at the end of this function */
1560 if (priv & OPpSORT_INPLACE) {
1561 assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV);
1562 (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */
1564 max = AvFILL(av) + 1;
1565 if (SvMAGICAL(av)) {
1568 for (i=0; i < max; i++) {
1569 SV **svp = av_fetch(av, i, FALSE);
1570 *SP++ = (svp) ? *svp : Nullsv;
1574 p1 = p2 = AvARRAY(av);
1583 if (priv & OPpSORT_DESCEND) {
1584 sortsvp = S_sortsv_desc;
1587 /* shuffle stack down, removing optional initial cv (p1!=p2), plus
1588 * any nulls; also stringify or converting to integer or number as
1589 * required any args */
1590 for (i=max; i > 0 ; i--) {
1591 if ((*p1 = *p2++)) { /* Weed out nulls. */
1594 if (priv & OPpSORT_NUMERIC) {
1595 if (priv & OPpSORT_INTEGER) {
1604 if (!SvNSIOK(*p1)) {
1610 if (all_SIVs && !SvSIOK(*p1))
1619 (void)sv_2pv_flags(*p1, 0,
1620 SV_GMAGIC|SV_CONST_RETURN);
1630 AvFILLp(av) = max-1;
1637 const bool oldcatch = CATCH_GET;
1643 PUSHSTACKi(PERLSI_SORT);
1644 if (!hasargs && !is_xsub) {
1645 if (PL_sortstash != stash || !PL_firstgv || !PL_secondgv) {
1646 SAVESPTR(PL_firstgv);
1647 SAVESPTR(PL_secondgv);
1648 PL_firstgv = gv_fetchpv("a", TRUE, SVt_PV);
1649 PL_secondgv = gv_fetchpv("b", TRUE, SVt_PV);
1650 PL_sortstash = stash;
1652 SAVESPTR(GvSV(PL_firstgv));
1653 SAVESPTR(GvSV(PL_secondgv));
1656 PUSHBLOCK(cx, CXt_NULL, PL_stack_base);
1657 if (!(flags & OPf_SPECIAL)) {
1658 cx->cx_type = CXt_SUB;
1659 cx->blk_gimme = G_SCALAR;
1662 PL_sortcxix = cxstack_ix;
1664 if (hasargs && !is_xsub) {
1665 /* This is mostly copied from pp_entersub */
1666 AV *av = (AV*)PAD_SVl(0);
1668 cx->blk_sub.savearray = GvAV(PL_defgv);
1669 GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av);
1670 CX_CURPAD_SAVE(cx->blk_sub);
1671 cx->blk_sub.argarray = av;
1675 sortsvp(aTHX_ start, max,
1676 is_xsub ? sortcv_xsub : hasargs ? sortcv_stacked : sortcv);
1678 POPBLOCK(cx,PL_curpm);
1679 PL_stack_sp = newsp;
1681 CATCH_SET(oldcatch);
1684 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */
1685 start = sorting_av ? AvARRAY(av) : ORIGMARK+1;
1686 sortsvp(aTHX_ start, max,
1687 (priv & OPpSORT_NUMERIC)
1688 ? ( ( ( priv & OPpSORT_INTEGER) || all_SIVs)
1689 ? ( overloading ? amagic_i_ncmp : sv_i_ncmp)
1690 : ( overloading ? amagic_ncmp : sv_ncmp ) )
1691 : ( IN_LOCALE_RUNTIME
1694 : sv_cmp_locale_static)
1695 : ( overloading ? amagic_cmp : sv_cmp_static)));
1697 if (priv & OPpSORT_REVERSE) {
1698 SV **q = start+max-1;
1706 if (av && !sorting_av) {
1707 /* simulate pp_aassign of tied AV */
1708 SV** const base = ORIGMARK+1;
1709 for (i=0; i < max; i++) {
1710 base[i] = newSVsv(base[i]);
1714 for (i=0; i < max; i++) {
1715 SV * const sv = base[i];
1716 SV **didstore = av_store(av, i, sv);
1724 PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max);
1729 sortcv(pTHX_ SV *a, SV *b)
1732 const I32 oldsaveix = PL_savestack_ix;
1733 const I32 oldscopeix = PL_scopestack_ix;
1735 GvSV(PL_firstgv) = a;
1736 GvSV(PL_secondgv) = b;
1737 PL_stack_sp = PL_stack_base;
1740 if (PL_stack_sp != PL_stack_base + 1)
1741 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1742 if (!SvNIOKp(*PL_stack_sp))
1743 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1744 result = SvIV(*PL_stack_sp);
1745 while (PL_scopestack_ix > oldscopeix) {
1748 leave_scope(oldsaveix);
1753 sortcv_stacked(pTHX_ SV *a, SV *b)
1756 const I32 oldsaveix = PL_savestack_ix;
1757 const I32 oldscopeix = PL_scopestack_ix;
1759 AV * const av = GvAV(PL_defgv);
1761 if (AvMAX(av) < 1) {
1762 SV** ary = AvALLOC(av);
1763 if (AvARRAY(av) != ary) {
1764 AvMAX(av) += AvARRAY(av) - AvALLOC(av);
1765 SvPV_set(av, (char*)ary);
1767 if (AvMAX(av) < 1) {
1770 SvPV_set(av, (char*)ary);
1777 PL_stack_sp = PL_stack_base;
1780 if (PL_stack_sp != PL_stack_base + 1)
1781 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1782 if (!SvNIOKp(*PL_stack_sp))
1783 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1784 result = SvIV(*PL_stack_sp);
1785 while (PL_scopestack_ix > oldscopeix) {
1788 leave_scope(oldsaveix);
1793 sortcv_xsub(pTHX_ SV *a, SV *b)
1796 const I32 oldsaveix = PL_savestack_ix;
1797 const I32 oldscopeix = PL_scopestack_ix;
1798 CV * const cv=(CV*)PL_sortcop;
1807 (void)(*CvXSUB(cv))(aTHX_ cv);
1808 if (PL_stack_sp != PL_stack_base + 1)
1809 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1810 if (!SvNIOKp(*PL_stack_sp))
1811 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1812 result = SvIV(*PL_stack_sp);
1813 while (PL_scopestack_ix > oldscopeix) {
1816 leave_scope(oldsaveix);
1822 sv_ncmp(pTHX_ SV *a, SV *b)
1824 const NV nv1 = SvNSIV(a);
1825 const NV nv2 = SvNSIV(b);
1826 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0;
1830 sv_i_ncmp(pTHX_ SV *a, SV *b)
1832 const IV iv1 = SvIV(a);
1833 const IV iv2 = SvIV(b);
1834 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0;
1837 #define tryCALL_AMAGICbin(left,right,meth) \
1838 (PL_amagic_generation && (SvAMAGIC(left)||SvAMAGIC(right))) \
1839 ? amagic_call(left, right, CAT2(meth,_amg), 0) \
1843 amagic_ncmp(pTHX_ register SV *a, register SV *b)
1845 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp);
1848 const I32 i = SvIVX(tmpsv);
1854 const NV d = SvNV(tmpsv);
1860 return sv_ncmp(aTHX_ a, b);
1864 amagic_i_ncmp(pTHX_ register SV *a, register SV *b)
1866 SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp);
1869 const I32 i = SvIVX(tmpsv);
1875 const NV d = SvNV(tmpsv);
1881 return sv_i_ncmp(aTHX_ a, b);
1885 amagic_cmp(pTHX_ register SV *str1, register SV *str2)
1887 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp);
1890 const I32 i = SvIVX(tmpsv);
1896 const NV d = SvNV(tmpsv);
1902 return sv_cmp(str1, str2);
1906 amagic_cmp_locale(pTHX_ register SV *str1, register SV *str2)
1908 SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp);
1911 const I32 i = SvIVX(tmpsv);
1917 const NV d = SvNV(tmpsv);
1923 return sv_cmp_locale(str1, str2);
1928 * c-indentation-style: bsd
1930 * indent-tabs-mode: t
1933 * ex: set ts=8 sts=4 sw=4 noet: