3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 * 2000, 2001, 2002, 2003, 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...
17 #define PERL_IN_PP_SORT_C
21 /* looks like 'small' is reserved word for WINCE (or somesuch)*/
25 static I32 sortcv(pTHX_ SV *a, SV *b);
26 static I32 sortcv_stacked(pTHX_ SV *a, SV *b);
27 static I32 sortcv_xsub(pTHX_ SV *a, SV *b);
28 static I32 sv_ncmp(pTHX_ SV *a, SV *b);
29 static I32 sv_i_ncmp(pTHX_ SV *a, SV *b);
30 static I32 amagic_ncmp(pTHX_ SV *a, SV *b);
31 static I32 amagic_i_ncmp(pTHX_ SV *a, SV *b);
32 static I32 amagic_cmp(pTHX_ SV *a, SV *b);
33 static I32 amagic_cmp_locale(pTHX_ SV *a, SV *b);
35 #define sv_cmp_static Perl_sv_cmp
36 #define sv_cmp_locale_static Perl_sv_cmp_locale
38 #define SORTHINTS(hintsv) \
39 (((hintsv) = GvSV(gv_fetchpv("sort::hints", GV_ADDMULTI, SVt_IV))), \
40 (SvIOK(hintsv) ? ((I32)SvIV(hintsv)) : 0))
43 #define SMALLSORT (200)
47 * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>.
49 * The original code was written in conjunction with BSD Computer Software
50 * Research Group at University of California, Berkeley.
52 * See also: "Optimistic Merge Sort" (SODA '92)
54 * The integration to Perl is by John P. Linderman <jpl@research.att.com>.
56 * The code can be distributed under the same terms as Perl itself.
61 typedef char * aptr; /* pointer for arithmetic on sizes */
62 typedef SV * gptr; /* pointers in our lists */
64 /* Binary merge internal sort, with a few special mods
65 ** for the special perl environment it now finds itself in.
67 ** Things that were once options have been hotwired
68 ** to values suitable for this use. In particular, we'll always
69 ** initialize looking for natural runs, we'll always produce stable
70 ** output, and we'll always do Peter McIlroy's binary merge.
73 /* Pointer types for arithmetic and storage and convenience casts */
75 #define APTR(P) ((aptr)(P))
76 #define GPTP(P) ((gptr *)(P))
77 #define GPPP(P) ((gptr **)(P))
80 /* byte offset from pointer P to (larger) pointer Q */
81 #define BYTEOFF(P, Q) (APTR(Q) - APTR(P))
83 #define PSIZE sizeof(gptr)
85 /* If PSIZE is power of 2, make PSHIFT that power, if that helps */
88 #define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT))
89 #define PNBYTE(N) ((N) << (PSHIFT))
90 #define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N)))
92 /* Leave optimization to compiler */
93 #define PNELEM(P, Q) (GPTP(Q) - GPTP(P))
94 #define PNBYTE(N) ((N) * (PSIZE))
95 #define PINDEX(P, N) (GPTP(P) + (N))
98 /* Pointer into other corresponding to pointer into this */
99 #define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P))
101 #define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim)
104 /* Runs are identified by a pointer in the auxilliary list.
105 ** The pointer is at the start of the list,
106 ** and it points to the start of the next list.
107 ** NEXT is used as an lvalue, too.
110 #define NEXT(P) (*GPPP(P))
113 /* PTHRESH is the minimum number of pairs with the same sense to justify
114 ** checking for a run and extending it. Note that PTHRESH counts PAIRS,
115 ** not just elements, so PTHRESH == 8 means a run of 16.
120 /* RTHRESH is the number of elements in a run that must compare low
121 ** to the low element from the opposing run before we justify
122 ** doing a binary rampup instead of single stepping.
123 ** In random input, N in a row low should only happen with
124 ** probability 2^(1-N), so we can risk that we are dealing
125 ** with orderly input without paying much when we aren't.
132 ** Overview of algorithm and variables.
133 ** The array of elements at list1 will be organized into runs of length 2,
134 ** or runs of length >= 2 * PTHRESH. We only try to form long runs when
135 ** PTHRESH adjacent pairs compare in the same way, suggesting overall order.
137 ** Unless otherwise specified, pair pointers address the first of two elements.
139 ** b and b+1 are a pair that compare with sense ``sense''.
140 ** b is the ``bottom'' of adjacent pairs that might form a longer run.
142 ** p2 parallels b in the list2 array, where runs are defined by
145 ** t represents the ``top'' of the adjacent pairs that might extend
146 ** the run beginning at b. Usually, t addresses a pair
147 ** that compares with opposite sense from (b,b+1).
148 ** However, it may also address a singleton element at the end of list1,
149 ** or it may be equal to ``last'', the first element beyond list1.
151 ** r addresses the Nth pair following b. If this would be beyond t,
152 ** we back it off to t. Only when r is less than t do we consider the
153 ** run long enough to consider checking.
155 ** q addresses a pair such that the pairs at b through q already form a run.
156 ** Often, q will equal b, indicating we only are sure of the pair itself.
157 ** However, a search on the previous cycle may have revealed a longer run,
158 ** so q may be greater than b.
160 ** p is used to work back from a candidate r, trying to reach q,
161 ** which would mean b through r would be a run. If we discover such a run,
162 ** we start q at r and try to push it further towards t.
163 ** If b through r is NOT a run, we detect the wrong order at (p-1,p).
164 ** In any event, after the check (if any), we have two main cases.
166 ** 1) Short run. b <= q < p <= r <= t.
167 ** b through q is a run (perhaps trivial)
168 ** q through p are uninteresting pairs
169 ** p through r is a run
171 ** 2) Long run. b < r <= q < t.
172 ** b through q is a run (of length >= 2 * PTHRESH)
174 ** Note that degenerate cases are not only possible, but likely.
175 ** For example, if the pair following b compares with opposite sense,
176 ** then b == q < p == r == t.
181 dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, SVCOMPARE_t cmp)
184 register gptr *b, *p, *q, *t, *p2;
185 register gptr c, *last, *r;
190 last = PINDEX(b, nmemb);
191 sense = (cmp(aTHX_ *b, *(b+1)) > 0);
192 for (p2 = list2; b < last; ) {
193 /* We just started, or just reversed sense.
194 ** Set t at end of pairs with the prevailing sense.
196 for (p = b+2, t = p; ++p < last; t = ++p) {
197 if ((cmp(aTHX_ *t, *p) > 0) != sense) break;
200 /* Having laid out the playing field, look for long runs */
202 p = r = b + (2 * PTHRESH);
203 if (r >= t) p = r = t; /* too short to care about */
205 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) &&
208 /* b through r is a (long) run.
209 ** Extend it as far as possible.
212 while (((p += 2) < t) &&
213 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p;
214 r = p = q + 2; /* no simple pairs, no after-run */
217 if (q > b) { /* run of greater than 2 at b */
220 /* pick up singleton, if possible */
223 ((cmp(aTHX_ *(p-1), *p) > 0) == sense))
224 savep = r = p = q = last;
225 p2 = NEXT(p2) = p2 + (p - b); ++runs;
226 if (sense) while (b < --p) {
233 while (q < p) { /* simple pairs */
234 p2 = NEXT(p2) = p2 + 2; ++runs;
241 if (((b = p) == t) && ((t+1) == last)) {
242 NEXT(p2) = p2 + 1; ++runs;
253 /* The original merge sort, in use since 5.7, was as fast as, or faster than,
254 * qsort on many platforms, but slower than qsort, conspicuously so,
255 * on others. The most likely explanation was platform-specific
256 * differences in cache sizes and relative speeds.
258 * The quicksort divide-and-conquer algorithm guarantees that, as the
259 * problem is subdivided into smaller and smaller parts, the parts
260 * fit into smaller (and faster) caches. So it doesn't matter how
261 * many levels of cache exist, quicksort will "find" them, and,
262 * as long as smaller is faster, take advanatge of them.
264 * By contrast, consider how the original mergesort algorithm worked.
265 * Suppose we have five runs (each typically of length 2 after dynprep).
274 * Adjacent pairs are merged in "grand sweeps" through the input.
275 * This means, on pass 1, the records in runs 1 and 2 aren't revisited until
276 * runs 3 and 4 are merged and the runs from run 5 have been copied.
277 * The only cache that matters is one large enough to hold *all* the input.
278 * On some platforms, this may be many times slower than smaller caches.
280 * The following pseudo-code uses the same basic merge algorithm,
281 * but in a divide-and-conquer way.
283 * # merge $runs runs at offset $offset of list $list1 into $list2.
284 * # all unmerged runs ($runs == 1) originate in list $base.
286 * my ($offset, $runs, $base, $list1, $list2) = @_;
289 * if ($list1 is $base) copy run to $list2
290 * return offset of end of list (or copy)
292 * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1)
293 * mgsort2($off2, $runs/2, $base, $list2, $list1)
294 * merge the adjacent runs at $offset of $list1 into $list2
295 * return the offset of the end of the merged runs
298 * mgsort2(0, $runs, $base, $aux, $base);
300 * For our 5 runs, the tree of calls looks like
309 * and the corresponding activity looks like
311 * copy runs 1 and 2 from base to aux
312 * merge runs 1 and 2 from aux to base
313 * (run 3 is where it belongs, no copy needed)
314 * merge runs 12 and 3 from base to aux
315 * (runs 4 and 5 are where they belong, no copy needed)
316 * merge runs 4 and 5 from base to aux
317 * merge runs 123 and 45 from aux to base
319 * Note that we merge runs 1 and 2 immediately after copying them,
320 * while they are still likely to be in fast cache. Similarly,
321 * run 3 is merged with run 12 while it still may be lingering in cache.
322 * This implementation should therefore enjoy much of the cache-friendly
323 * behavior that quicksort does. In addition, it does less copying
324 * than the original mergesort implementation (only runs 1 and 2 are copied)
325 * and the "balancing" of merges is better (merged runs comprise more nearly
326 * equal numbers of original runs).
328 * The actual cache-friendly implementation will use a pseudo-stack
329 * to avoid recursion, and will unroll processing of runs of length 2,
330 * but it is otherwise similar to the recursive implementation.
334 IV offset; /* offset of 1st of 2 runs at this level */
335 IV runs; /* how many runs must be combined into 1 */
336 } off_runs; /* pseudo-stack element */
339 S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp)
341 IV i, run, runs, offset;
344 register gptr *f1, *f2, *t, *b, *p, *tp2, *l1, *l2, *q;
345 gptr *aux, *list1, *list2;
347 gptr small[SMALLSORT];
349 off_runs stack[60], *stackp;
351 if (nmemb <= 1) return; /* sorted trivially */
352 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */
353 else { New(799,aux,nmemb,gptr); } /* allocate auxilliary array */
356 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp);
357 stackp->offset = offset = 0;
358 which[0] = which[2] = base;
361 /* On levels where both runs have be constructed (stackp->runs == 0),
362 * merge them, and note the offset of their end, in case the offset
363 * is needed at the next level up. Hop up a level, and,
364 * as long as stackp->runs is 0, keep merging.
366 if ((runs = stackp->runs) == 0) {
368 list1 = which[iwhich]; /* area where runs are now */
369 list2 = which[++iwhich]; /* area for merged runs */
371 offset = stackp->offset;
372 f1 = p1 = list1 + offset; /* start of first run */
373 p = tp2 = list2 + offset; /* where merged run will go */
374 t = NEXT(p); /* where first run ends */
375 f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */
376 t = NEXT(t); /* where second runs ends */
377 l2 = POTHER(t, list2, list1); /* ... on the other side */
378 offset = PNELEM(list2, t);
379 while (f1 < l1 && f2 < l2) {
380 /* If head 1 is larger than head 2, find ALL the elements
381 ** in list 2 strictly less than head1, write them all,
382 ** then head 1. Then compare the new heads, and repeat,
383 ** until one or both lists are exhausted.
385 ** In all comparisons (after establishing
386 ** which head to merge) the item to merge
387 ** (at pointer q) is the first operand of
388 ** the comparison. When we want to know
389 ** if ``q is strictly less than the other'',
392 ** because stability demands that we treat equality
393 ** as high when q comes from l2, and as low when
394 ** q was from l1. So we ask the question by doing
395 ** cmp(q, other) <= sense
396 ** and make sense == 0 when equality should look low,
397 ** and -1 when equality should look high.
401 if (cmp(aTHX_ *f1, *f2) <= 0) {
402 q = f2; b = f1; t = l1;
405 q = f1; b = f2; t = l2;
412 ** Leave t at something strictly
413 ** greater than q (or at the end of the list),
414 ** and b at something strictly less than q.
416 for (i = 1, run = 0 ;;) {
417 if ((p = PINDEX(b, i)) >= t) {
419 if (((p = PINDEX(t, -1)) > b) &&
420 (cmp(aTHX_ *q, *p) <= sense))
424 } else if (cmp(aTHX_ *q, *p) <= sense) {
428 if (++run >= RTHRESH) i += i;
432 /* q is known to follow b and must be inserted before t.
433 ** Increment b, so the range of possibilities is [b,t).
434 ** Round binary split down, to favor early appearance.
435 ** Adjust b and t until q belongs just before t.
440 p = PINDEX(b, (PNELEM(b, t) - 1) / 2);
441 if (cmp(aTHX_ *q, *p) <= sense) {
447 /* Copy all the strictly low elements */
450 FROMTOUPTO(f2, tp2, t);
453 FROMTOUPTO(f1, tp2, t);
459 /* Run out remaining list */
461 if (f2 < l2) FROMTOUPTO(f2, tp2, l2);
462 } else FROMTOUPTO(f1, tp2, l1);
463 p1 = NEXT(p1) = POTHER(tp2, list2, list1);
465 if (--level == 0) goto done;
467 t = list1; list1 = list2; list2 = t; /* swap lists */
468 } while ((runs = stackp->runs) == 0);
472 stackp->runs = 0; /* current run will finish level */
473 /* While there are more than 2 runs remaining,
474 * turn them into exactly 2 runs (at the "other" level),
475 * each made up of approximately half the runs.
476 * Stack the second half for later processing,
477 * and set about producing the first half now.
482 stackp->offset = offset;
483 runs -= stackp->runs = runs / 2;
485 /* We must construct a single run from 1 or 2 runs.
486 * All the original runs are in which[0] == base.
487 * The run we construct must end up in which[level&1].
491 /* Constructing a single run from a single run.
492 * If it's where it belongs already, there's nothing to do.
493 * Otherwise, copy it to where it belongs.
494 * A run of 1 is either a singleton at level 0,
495 * or the second half of a split 3. In neither event
496 * is it necessary to set offset. It will be set by the merge
497 * that immediately follows.
499 if (iwhich) { /* Belongs in aux, currently in base */
500 f1 = b = PINDEX(base, offset); /* where list starts */
501 f2 = PINDEX(aux, offset); /* where list goes */
502 t = NEXT(f2); /* where list will end */
503 offset = PNELEM(aux, t); /* offset thereof */
504 t = PINDEX(base, offset); /* where it currently ends */
505 FROMTOUPTO(f1, f2, t); /* copy */
506 NEXT(b) = t; /* set up parallel pointer */
507 } else if (level == 0) goto done; /* single run at level 0 */
509 /* Constructing a single run from two runs.
510 * The merge code at the top will do that.
511 * We need only make sure the two runs are in the "other" array,
512 * so they'll end up in the correct array after the merge.
516 stackp->offset = offset;
517 stackp->runs = 0; /* take care of both runs, trigger merge */
518 if (!iwhich) { /* Merged runs belong in aux, copy 1st */
519 f1 = b = PINDEX(base, offset); /* where first run starts */
520 f2 = PINDEX(aux, offset); /* where it will be copied */
521 t = NEXT(f2); /* where first run will end */
522 offset = PNELEM(aux, t); /* offset thereof */
523 p = PINDEX(base, offset); /* end of first run */
524 t = NEXT(t); /* where second run will end */
525 t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */
526 FROMTOUPTO(f1, f2, t); /* copy both runs */
527 NEXT(b) = p; /* paralled pointer for 1st */
528 NEXT(p) = t; /* ... and for second */
533 if (aux != small) Safefree(aux); /* free iff allocated */
538 * The quicksort implementation was derived from source code contributed
541 * NOTE: this code was derived from Tom Horsley's qsort replacement
542 * and should not be confused with the original code.
545 /* Copyright (C) Tom Horsley, 1997. All rights reserved.
547 Permission granted to distribute under the same terms as perl which are
550 This program is free software; you can redistribute it and/or modify
551 it under the terms of either:
553 a) the GNU General Public License as published by the Free
554 Software Foundation; either version 1, or (at your option) any
557 b) the "Artistic License" which comes with this Kit.
559 Details on the perl license can be found in the perl source code which
560 may be located via the www.perl.com web page.
562 This is the most wonderfulest possible qsort I can come up with (and
563 still be mostly portable) My (limited) tests indicate it consistently
564 does about 20% fewer calls to compare than does the qsort in the Visual
565 C++ library, other vendors may vary.
567 Some of the ideas in here can be found in "Algorithms" by Sedgewick,
568 others I invented myself (or more likely re-invented since they seemed
569 pretty obvious once I watched the algorithm operate for a while).
571 Most of this code was written while watching the Marlins sweep the Giants
572 in the 1997 National League Playoffs - no Braves fans allowed to use this
573 code (just kidding :-).
575 I realize that if I wanted to be true to the perl tradition, the only
576 comment in this file would be something like:
578 ...they shuffled back towards the rear of the line. 'No, not at the
579 rear!' the slave-driver shouted. 'Three files up. And stay there...
581 However, I really needed to violate that tradition just so I could keep
582 track of what happens myself, not to mention some poor fool trying to
583 understand this years from now :-).
586 /* ********************************************************** Configuration */
588 #ifndef QSORT_ORDER_GUESS
589 #define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */
592 /* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for
593 future processing - a good max upper bound is log base 2 of memory size
594 (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can
595 safely be smaller than that since the program is taking up some space and
596 most operating systems only let you grab some subset of contiguous
597 memory (not to mention that you are normally sorting data larger than
598 1 byte element size :-).
600 #ifndef QSORT_MAX_STACK
601 #define QSORT_MAX_STACK 32
604 /* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort.
605 Anything bigger and we use qsort. If you make this too small, the qsort
606 will probably break (or become less efficient), because it doesn't expect
607 the middle element of a partition to be the same as the right or left -
608 you have been warned).
610 #ifndef QSORT_BREAK_EVEN
611 #define QSORT_BREAK_EVEN 6
614 /* QSORT_PLAY_SAFE is the size of the largest partition we're willing
615 to go quadratic on. We innoculate larger partitions against
616 quadratic behavior by shuffling them before sorting. This is not
617 an absolute guarantee of non-quadratic behavior, but it would take
618 staggeringly bad luck to pick extreme elements as the pivot
619 from randomized data.
621 #ifndef QSORT_PLAY_SAFE
622 #define QSORT_PLAY_SAFE 255
625 /* ************************************************************* Data Types */
627 /* hold left and right index values of a partition waiting to be sorted (the
628 partition includes both left and right - right is NOT one past the end or
631 struct partition_stack_entry {
634 #ifdef QSORT_ORDER_GUESS
635 int qsort_break_even;
639 /* ******************************************************* Shorthand Macros */
641 /* Note that these macros will be used from inside the qsort function where
642 we happen to know that the variable 'elt_size' contains the size of an
643 array element and the variable 'temp' points to enough space to hold a
644 temp element and the variable 'array' points to the array being sorted
645 and 'compare' is the pointer to the compare routine.
647 Also note that there are very many highly architecture specific ways
648 these might be sped up, but this is simply the most generally portable
649 code I could think of.
652 /* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2
654 #define qsort_cmp(elt1, elt2) \
655 ((*compare)(aTHX_ array[elt1], array[elt2]))
657 #ifdef QSORT_ORDER_GUESS
658 #define QSORT_NOTICE_SWAP swapped++;
660 #define QSORT_NOTICE_SWAP
663 /* swaps contents of array elements elt1, elt2.
665 #define qsort_swap(elt1, elt2) \
668 temp = array[elt1]; \
669 array[elt1] = array[elt2]; \
670 array[elt2] = temp; \
673 /* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets
674 elt3 and elt3 gets elt1.
676 #define qsort_rotate(elt1, elt2, elt3) \
679 temp = array[elt1]; \
680 array[elt1] = array[elt2]; \
681 array[elt2] = array[elt3]; \
682 array[elt3] = temp; \
685 /* ************************************************************ Debug stuff */
692 return; /* good place to set a breakpoint */
695 #define qsort_assert(t) (void)( (t) || (break_here(), 0) )
702 int (*compare)(const void * elt1, const void * elt2),
703 int pc_left, int pc_right, int u_left, int u_right)
707 qsort_assert(pc_left <= pc_right);
708 qsort_assert(u_right < pc_left);
709 qsort_assert(pc_right < u_left);
710 for (i = u_right + 1; i < pc_left; ++i) {
711 qsort_assert(qsort_cmp(i, pc_left) < 0);
713 for (i = pc_left; i < pc_right; ++i) {
714 qsort_assert(qsort_cmp(i, pc_right) == 0);
716 for (i = pc_right + 1; i < u_left; ++i) {
717 qsort_assert(qsort_cmp(pc_right, i) < 0);
721 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \
722 doqsort_all_asserts(array, num_elts, elt_size, compare, \
723 PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT)
727 #define qsort_assert(t) ((void)0)
729 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0)
733 /* ****************************************************************** qsort */
735 STATIC void /* the standard unstable (u) quicksort (qsort) */
736 S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare)
740 struct partition_stack_entry partition_stack[QSORT_MAX_STACK];
741 int next_stack_entry = 0;
745 #ifdef QSORT_ORDER_GUESS
746 int qsort_break_even;
750 /* Make sure we actually have work to do.
756 /* Innoculate large partitions against quadratic behavior */
757 if (num_elts > QSORT_PLAY_SAFE) {
758 register size_t n, j;
760 for (n = num_elts, q = array; n > 1; ) {
761 j = (size_t)(n-- * Drand01());
768 /* Setup the initial partition definition and fall into the sorting loop
771 part_right = (int)(num_elts - 1);
772 #ifdef QSORT_ORDER_GUESS
773 qsort_break_even = QSORT_BREAK_EVEN;
775 #define qsort_break_even QSORT_BREAK_EVEN
778 if ((part_right - part_left) >= qsort_break_even) {
779 /* OK, this is gonna get hairy, so lets try to document all the
780 concepts and abbreviations and variables and what they keep
783 pc: pivot chunk - the set of array elements we accumulate in the
784 middle of the partition, all equal in value to the original
785 pivot element selected. The pc is defined by:
787 pc_left - the leftmost array index of the pc
788 pc_right - the rightmost array index of the pc
790 we start with pc_left == pc_right and only one element
791 in the pivot chunk (but it can grow during the scan).
793 u: uncompared elements - the set of elements in the partition
794 we have not yet compared to the pivot value. There are two
795 uncompared sets during the scan - one to the left of the pc
796 and one to the right.
798 u_right - the rightmost index of the left side's uncompared set
799 u_left - the leftmost index of the right side's uncompared set
801 The leftmost index of the left sides's uncompared set
802 doesn't need its own variable because it is always defined
803 by the leftmost edge of the whole partition (part_left). The
804 same goes for the rightmost edge of the right partition
807 We know there are no uncompared elements on the left once we
808 get u_right < part_left and no uncompared elements on the
809 right once u_left > part_right. When both these conditions
810 are met, we have completed the scan of the partition.
812 Any elements which are between the pivot chunk and the
813 uncompared elements should be less than the pivot value on
814 the left side and greater than the pivot value on the right
815 side (in fact, the goal of the whole algorithm is to arrange
816 for that to be true and make the groups of less-than and
817 greater-then elements into new partitions to sort again).
819 As you marvel at the complexity of the code and wonder why it
820 has to be so confusing. Consider some of the things this level
823 Once I do a compare, I squeeze every ounce of juice out of it. I
824 never do compare calls I don't have to do, and I certainly never
827 I also never swap any elements unless I can prove there is a
828 good reason. Many sort algorithms will swap a known value with
829 an uncompared value just to get things in the right place (or
830 avoid complexity :-), but that uncompared value, once it gets
831 compared, may then have to be swapped again. A lot of the
832 complexity of this code is due to the fact that it never swaps
833 anything except compared values, and it only swaps them when the
834 compare shows they are out of position.
836 int pc_left, pc_right;
841 pc_left = ((part_left + part_right) / 2);
843 u_right = pc_left - 1;
844 u_left = pc_right + 1;
846 /* Qsort works best when the pivot value is also the median value
847 in the partition (unfortunately you can't find the median value
848 without first sorting :-), so to give the algorithm a helping
849 hand, we pick 3 elements and sort them and use the median value
850 of that tiny set as the pivot value.
852 Some versions of qsort like to use the left middle and right as
853 the 3 elements to sort so they can insure the ends of the
854 partition will contain values which will stop the scan in the
855 compare loop, but when you have to call an arbitrarily complex
856 routine to do a compare, its really better to just keep track of
857 array index values to know when you hit the edge of the
858 partition and avoid the extra compare. An even better reason to
859 avoid using a compare call is the fact that you can drop off the
860 edge of the array if someone foolishly provides you with an
861 unstable compare function that doesn't always provide consistent
864 So, since it is simpler for us to compare the three adjacent
865 elements in the middle of the partition, those are the ones we
866 pick here (conveniently pointed at by u_right, pc_left, and
867 u_left). The values of the left, center, and right elements
868 are refered to as l c and r in the following comments.
871 #ifdef QSORT_ORDER_GUESS
874 s = qsort_cmp(u_right, pc_left);
877 s = qsort_cmp(pc_left, u_left);
878 /* if l < c, c < r - already in order - nothing to do */
880 /* l < c, c == r - already in order, pc grows */
882 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
884 /* l < c, c > r - need to know more */
885 s = qsort_cmp(u_right, u_left);
887 /* l < c, c > r, l < r - swap c & r to get ordered */
888 qsort_swap(pc_left, u_left);
889 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
891 /* l < c, c > r, l == r - swap c&r, grow pc */
892 qsort_swap(pc_left, u_left);
894 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
896 /* l < c, c > r, l > r - make lcr into rlc to get ordered */
897 qsort_rotate(pc_left, u_right, u_left);
898 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
903 s = qsort_cmp(pc_left, u_left);
905 /* l == c, c < r - already in order, grow pc */
907 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
909 /* l == c, c == r - already in order, grow pc both ways */
912 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
914 /* l == c, c > r - swap l & r, grow pc */
915 qsort_swap(u_right, u_left);
917 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
921 s = qsort_cmp(pc_left, u_left);
923 /* l > c, c < r - need to know more */
924 s = qsort_cmp(u_right, u_left);
926 /* l > c, c < r, l < r - swap l & c to get ordered */
927 qsort_swap(u_right, pc_left);
928 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
930 /* l > c, c < r, l == r - swap l & c, grow pc */
931 qsort_swap(u_right, pc_left);
933 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
935 /* l > c, c < r, l > r - rotate lcr into crl to order */
936 qsort_rotate(u_right, pc_left, u_left);
937 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
940 /* l > c, c == r - swap ends, grow pc */
941 qsort_swap(u_right, u_left);
943 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
945 /* l > c, c > r - swap ends to get in order */
946 qsort_swap(u_right, u_left);
947 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
950 /* We now know the 3 middle elements have been compared and
951 arranged in the desired order, so we can shrink the uncompared
956 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
958 /* The above massive nested if was the simple part :-). We now have
959 the middle 3 elements ordered and we need to scan through the
960 uncompared sets on either side, swapping elements that are on
961 the wrong side or simply shuffling equal elements around to get
962 all equal elements into the pivot chunk.
966 int still_work_on_left;
967 int still_work_on_right;
969 /* Scan the uncompared values on the left. If I find a value
970 equal to the pivot value, move it over so it is adjacent to
971 the pivot chunk and expand the pivot chunk. If I find a value
972 less than the pivot value, then just leave it - its already
973 on the correct side of the partition. If I find a greater
974 value, then stop the scan.
976 while ((still_work_on_left = (u_right >= part_left))) {
977 s = qsort_cmp(u_right, pc_left);
982 if (pc_left != u_right) {
983 qsort_swap(u_right, pc_left);
989 qsort_assert(u_right < pc_left);
990 qsort_assert(pc_left <= pc_right);
991 qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0);
992 qsort_assert(qsort_cmp(pc_left, pc_right) == 0);
995 /* Do a mirror image scan of uncompared values on the right
997 while ((still_work_on_right = (u_left <= part_right))) {
998 s = qsort_cmp(pc_right, u_left);
1001 } else if (s == 0) {
1003 if (pc_right != u_left) {
1004 qsort_swap(pc_right, u_left);
1010 qsort_assert(u_left > pc_right);
1011 qsort_assert(pc_left <= pc_right);
1012 qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0);
1013 qsort_assert(qsort_cmp(pc_left, pc_right) == 0);
1016 if (still_work_on_left) {
1017 /* I know I have a value on the left side which needs to be
1018 on the right side, but I need to know more to decide
1019 exactly the best thing to do with it.
1021 if (still_work_on_right) {
1022 /* I know I have values on both side which are out of
1023 position. This is a big win because I kill two birds
1024 with one swap (so to speak). I can advance the
1025 uncompared pointers on both sides after swapping both
1026 of them into the right place.
1028 qsort_swap(u_right, u_left);
1031 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
1033 /* I have an out of position value on the left, but the
1034 right is fully scanned, so I "slide" the pivot chunk
1035 and any less-than values left one to make room for the
1036 greater value over on the right. If the out of position
1037 value is immediately adjacent to the pivot chunk (there
1038 are no less-than values), I can do that with a swap,
1039 otherwise, I have to rotate one of the less than values
1040 into the former position of the out of position value
1041 and the right end of the pivot chunk into the left end
1045 if (pc_left == u_right) {
1046 qsort_swap(u_right, pc_right);
1047 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
1049 qsort_rotate(u_right, pc_left, pc_right);
1050 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
1055 } else if (still_work_on_right) {
1056 /* Mirror image of complex case above: I have an out of
1057 position value on the right, but the left is fully
1058 scanned, so I need to shuffle things around to make room
1059 for the right value on the left.
1062 if (pc_right == u_left) {
1063 qsort_swap(u_left, pc_left);
1064 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1066 qsort_rotate(pc_right, pc_left, u_left);
1067 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1072 /* No more scanning required on either side of partition,
1073 break out of loop and figure out next set of partitions
1079 /* The elements in the pivot chunk are now in the right place. They
1080 will never move or be compared again. All I have to do is decide
1081 what to do with the stuff to the left and right of the pivot
1084 Notes on the QSORT_ORDER_GUESS ifdef code:
1086 1. If I just built these partitions without swapping any (or
1087 very many) elements, there is a chance that the elements are
1088 already ordered properly (being properly ordered will
1089 certainly result in no swapping, but the converse can't be
1092 2. A (properly written) insertion sort will run faster on
1093 already ordered data than qsort will.
1095 3. Perhaps there is some way to make a good guess about
1096 switching to an insertion sort earlier than partition size 6
1097 (for instance - we could save the partition size on the stack
1098 and increase the size each time we find we didn't swap, thus
1099 switching to insertion sort earlier for partitions with a
1100 history of not swapping).
1102 4. Naturally, if I just switch right away, it will make
1103 artificial benchmarks with pure ascending (or descending)
1104 data look really good, but is that a good reason in general?
1108 #ifdef QSORT_ORDER_GUESS
1110 #if QSORT_ORDER_GUESS == 1
1111 qsort_break_even = (part_right - part_left) + 1;
1113 #if QSORT_ORDER_GUESS == 2
1114 qsort_break_even *= 2;
1116 #if QSORT_ORDER_GUESS == 3
1117 int prev_break = qsort_break_even;
1118 qsort_break_even *= qsort_break_even;
1119 if (qsort_break_even < prev_break) {
1120 qsort_break_even = (part_right - part_left) + 1;
1124 qsort_break_even = QSORT_BREAK_EVEN;
1128 if (part_left < pc_left) {
1129 /* There are elements on the left which need more processing.
1130 Check the right as well before deciding what to do.
1132 if (pc_right < part_right) {
1133 /* We have two partitions to be sorted. Stack the biggest one
1134 and process the smallest one on the next iteration. This
1135 minimizes the stack height by insuring that any additional
1136 stack entries must come from the smallest partition which
1137 (because it is smallest) will have the fewest
1138 opportunities to generate additional stack entries.
1140 if ((part_right - pc_right) > (pc_left - part_left)) {
1141 /* stack the right partition, process the left */
1142 partition_stack[next_stack_entry].left = pc_right + 1;
1143 partition_stack[next_stack_entry].right = part_right;
1144 #ifdef QSORT_ORDER_GUESS
1145 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even;
1147 part_right = pc_left - 1;
1149 /* stack the left partition, process the right */
1150 partition_stack[next_stack_entry].left = part_left;
1151 partition_stack[next_stack_entry].right = pc_left - 1;
1152 #ifdef QSORT_ORDER_GUESS
1153 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even;
1155 part_left = pc_right + 1;
1157 qsort_assert(next_stack_entry < QSORT_MAX_STACK);
1160 /* The elements on the left are the only remaining elements
1161 that need sorting, arrange for them to be processed as the
1164 part_right = pc_left - 1;
1166 } else if (pc_right < part_right) {
1167 /* There is only one chunk on the right to be sorted, make it
1168 the new partition and loop back around.
1170 part_left = pc_right + 1;
1172 /* This whole partition wound up in the pivot chunk, so
1173 we need to get a new partition off the stack.
1175 if (next_stack_entry == 0) {
1176 /* the stack is empty - we are done */
1180 part_left = partition_stack[next_stack_entry].left;
1181 part_right = partition_stack[next_stack_entry].right;
1182 #ifdef QSORT_ORDER_GUESS
1183 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even;
1187 /* This partition is too small to fool with qsort complexity, just
1188 do an ordinary insertion sort to minimize overhead.
1191 /* Assume 1st element is in right place already, and start checking
1192 at 2nd element to see where it should be inserted.
1194 for (i = part_left + 1; i <= part_right; ++i) {
1196 /* Scan (backwards - just in case 'i' is already in right place)
1197 through the elements already sorted to see if the ith element
1198 belongs ahead of one of them.
1200 for (j = i - 1; j >= part_left; --j) {
1201 if (qsort_cmp(i, j) >= 0) {
1202 /* i belongs right after j
1209 /* Looks like we really need to move some things
1213 for (k = i - 1; k >= j; --k)
1214 array[k + 1] = array[k];
1219 /* That partition is now sorted, grab the next one, or get out
1220 of the loop if there aren't any more.
1223 if (next_stack_entry == 0) {
1224 /* the stack is empty - we are done */
1228 part_left = partition_stack[next_stack_entry].left;
1229 part_right = partition_stack[next_stack_entry].right;
1230 #ifdef QSORT_ORDER_GUESS
1231 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even;
1236 /* Believe it or not, the array is sorted at this point! */
1239 /* Stabilize what is, presumably, an otherwise unstable sort method.
1240 * We do that by allocating (or having on hand) an array of pointers
1241 * that is the same size as the original array of elements to be sorted.
1242 * We initialize this parallel array with the addresses of the original
1243 * array elements. This indirection can make you crazy.
1244 * Some pictures can help. After initializing, we have
1248 * | | --------------> | | ------> first element to be sorted
1250 * | | --------------> | | ------> second element to be sorted
1252 * | | --------------> | | ------> third element to be sorted
1256 * | | --------------> | | ------> n-1st element to be sorted
1258 * | | --------------> | | ------> n-th element to be sorted
1261 * During the sort phase, we leave the elements of list1 where they are,
1262 * and sort the pointers in the indirect array in the same order determined
1263 * by the original comparison routine on the elements pointed to.
1264 * Because we don't move the elements of list1 around through
1265 * this phase, we can break ties on elements that compare equal
1266 * using their address in the list1 array, ensuring stabilty.
1267 * This leaves us with something looking like
1271 * | | --+ +---> | | ------> first element to be sorted
1273 * | | --|-------|---> | | ------> second element to be sorted
1275 * | | --|-------+ +-> | | ------> third element to be sorted
1278 * +----+ | | | | +----+
1279 * | | ---|-+ | +--> | | ------> n-1st element to be sorted
1281 * | | ---+ +----> | | ------> n-th element to be sorted
1284 * where the i-th element of the indirect array points to the element
1285 * that should be i-th in the sorted array. After the sort phase,
1286 * we have to put the elements of list1 into the places
1287 * dictated by the indirect array.
1292 cmpindir(pTHX_ gptr a, gptr b)
1295 gptr *ap = (gptr *)a;
1296 gptr *bp = (gptr *)b;
1298 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)) == 0)
1299 sense = (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1304 S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp)
1308 if (SORTHINTS(hintsv) & HINT_SORT_STABLE) {
1309 register gptr **pp, *q;
1310 register size_t n, j, i;
1311 gptr *small[SMALLSORT], **indir, tmp;
1312 SVCOMPARE_t savecmp;
1313 if (nmemb <= 1) return; /* sorted trivially */
1315 /* Small arrays can use the stack, big ones must be allocated */
1316 if (nmemb <= SMALLSORT) indir = small;
1317 else { New(1799, indir, nmemb, gptr *); }
1319 /* Copy pointers to original array elements into indirect array */
1320 for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++;
1322 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
1323 PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */
1325 /* sort, with indirection */
1326 S_qsortsvu(aTHX_ (gptr *)indir, nmemb, cmpindir);
1330 for (n = nmemb; n--; ) {
1331 /* Assert A: all elements of q with index > n are already
1332 * in place. This is vacuosly true at the start, and we
1333 * put element n where it belongs below (if it wasn't
1334 * already where it belonged). Assert B: we only move
1335 * elements that aren't where they belong,
1336 * so, by A, we never tamper with elements above n.
1338 j = pp[n] - q; /* This sets j so that q[j] is
1339 * at pp[n]. *pp[j] belongs in
1340 * q[j], by construction.
1342 if (n != j) { /* all's well if n == j */
1343 tmp = q[j]; /* save what's in q[j] */
1345 q[j] = *pp[j]; /* put *pp[j] where it belongs */
1346 i = pp[j] - q; /* the index in q of the element
1348 pp[j] = q + j; /* this is ok now */
1349 } while ((j = i) != n);
1350 /* There are only finitely many (nmemb) addresses
1352 * So we must eventually revisit an index we saw before.
1353 * Suppose the first revisited index is k != n.
1354 * An index is visited because something else belongs there.
1355 * If we visit k twice, then two different elements must
1356 * belong in the same place, which cannot be.
1357 * So j must get back to n, the loop terminates,
1358 * and we put the saved element where it belongs.
1360 q[n] = tmp; /* put what belongs into
1361 * the n-th element */
1365 /* free iff allocated */
1366 if (indir != small) { Safefree(indir); }
1367 /* restore prevailing comparison routine */
1368 PL_sort_RealCmp = savecmp;
1370 S_qsortsvu(aTHX_ list1, nmemb, cmp);
1375 =head1 Array Manipulation Functions
1379 Sort an array. Here is an example:
1381 sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);
1383 See lib/sort.pm for details about controlling the sorting algorithm.
1389 Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1391 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) =
1396 /* Sun's Compiler (cc: WorkShop Compilers 4.2 30 Oct 1996 C 4.2) used
1397 to miscompile this function under optimization -O. If you get test
1398 errors related to picking the correct sort() function, try recompiling
1399 this file without optimiziation. -- A.D. 4/2002.
1401 hints = SORTHINTS(hintsv);
1402 if (hints & HINT_SORT_QUICKSORT) {
1403 sortsvp = S_qsortsv;
1406 /* The default as of 5.8.0 is mergesort */
1407 sortsvp = S_mergesortsv;
1410 sortsvp(aTHX_ array, nmemb, cmp);
1415 dSP; dMARK; dORIGMARK;
1417 SV **myorigmark = ORIGMARK;
1423 OP* nextop = PL_op->op_next;
1424 I32 overloading = 0;
1425 bool hasargs = FALSE;
1428 if (gimme != G_ARRAY) {
1434 SAVEVPTR(PL_sortcop);
1435 if (PL_op->op_flags & OPf_STACKED) {
1436 if (PL_op->op_flags & OPf_SPECIAL) {
1437 OP *kid = cLISTOP->op_first->op_sibling; /* pass pushmark */
1438 kid = kUNOP->op_first; /* pass rv2gv */
1439 kid = kUNOP->op_first; /* pass leave */
1440 PL_sortcop = kid->op_next;
1441 stash = CopSTASH(PL_curcop);
1444 cv = sv_2cv(*++MARK, &stash, &gv, 0);
1445 if (cv && SvPOK(cv)) {
1447 char *proto = SvPV((SV*)cv, n_a);
1448 if (proto && strEQ(proto, "$$")) {
1452 if (!(cv && CvROOT(cv))) {
1453 if (cv && CvXSUB(cv)) {
1457 SV *tmpstr = sv_newmortal();
1458 gv_efullname3(tmpstr, gv, Nullch);
1459 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called",
1463 DIE(aTHX_ "Undefined subroutine in sort");
1468 PL_sortcop = (OP*)cv;
1470 PL_sortcop = CvSTART(cv);
1471 SAVEVPTR(CvROOT(cv)->op_ppaddr);
1472 CvROOT(cv)->op_ppaddr = PL_ppaddr[OP_NULL];
1474 PAD_SET_CUR(CvPADLIST(cv), 1);
1479 PL_sortcop = Nullop;
1480 stash = CopSTASH(PL_curcop);
1483 up = myorigmark + 1;
1484 while (MARK < SP) { /* This may or may not shift down one here. */
1486 if ((*up = *++MARK)) { /* Weed out nulls. */
1488 if (!PL_sortcop && !SvPOK(*up)) {
1493 (void)sv_2pv(*up, &n_a);
1498 max = --up - myorigmark;
1503 bool oldcatch = CATCH_GET;
1509 PUSHSTACKi(PERLSI_SORT);
1510 if (!hasargs && !is_xsub) {
1511 if (PL_sortstash != stash || !PL_firstgv || !PL_secondgv) {
1512 SAVESPTR(PL_firstgv);
1513 SAVESPTR(PL_secondgv);
1514 PL_firstgv = gv_fetchpv("a", TRUE, SVt_PV);
1515 PL_secondgv = gv_fetchpv("b", TRUE, SVt_PV);
1516 PL_sortstash = stash;
1518 SAVESPTR(GvSV(PL_firstgv));
1519 SAVESPTR(GvSV(PL_secondgv));
1522 PUSHBLOCK(cx, CXt_NULL, PL_stack_base);
1523 if (!(PL_op->op_flags & OPf_SPECIAL)) {
1524 cx->cx_type = CXt_SUB;
1525 cx->blk_gimme = G_SCALAR;
1528 (void)SvREFCNT_inc(cv); /* in preparation for POPSUB */
1530 PL_sortcxix = cxstack_ix;
1532 if (hasargs && !is_xsub) {
1533 /* This is mostly copied from pp_entersub */
1534 AV *av = (AV*)PAD_SVl(0);
1536 cx->blk_sub.savearray = GvAV(PL_defgv);
1537 GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av);
1538 CX_CURPAD_SAVE(cx->blk_sub);
1539 cx->blk_sub.argarray = av;
1541 sortsv((myorigmark+1), max,
1542 is_xsub ? sortcv_xsub : hasargs ? sortcv_stacked : sortcv);
1544 POPBLOCK(cx,PL_curpm);
1545 PL_stack_sp = newsp;
1547 CATCH_SET(oldcatch);
1552 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */
1553 sortsv(ORIGMARK+1, max,
1554 (PL_op->op_private & OPpSORT_NUMERIC)
1555 ? ( (PL_op->op_private & OPpSORT_INTEGER)
1556 ? ( overloading ? amagic_i_ncmp : sv_i_ncmp)
1557 : ( overloading ? amagic_ncmp : sv_ncmp))
1558 : ( IN_LOCALE_RUNTIME
1561 : sv_cmp_locale_static)
1562 : ( overloading ? amagic_cmp : sv_cmp_static)));
1563 if (PL_op->op_private & OPpSORT_REVERSE) {
1564 SV **p = ORIGMARK+1;
1565 SV **q = ORIGMARK+max;
1575 PL_stack_sp = ORIGMARK + max;
1580 sortcv(pTHX_ SV *a, SV *b)
1582 I32 oldsaveix = PL_savestack_ix;
1583 I32 oldscopeix = PL_scopestack_ix;
1585 GvSV(PL_firstgv) = a;
1586 GvSV(PL_secondgv) = b;
1587 PL_stack_sp = PL_stack_base;
1590 if (PL_stack_sp != PL_stack_base + 1)
1591 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1592 if (!SvNIOKp(*PL_stack_sp))
1593 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1594 result = SvIV(*PL_stack_sp);
1595 while (PL_scopestack_ix > oldscopeix) {
1598 leave_scope(oldsaveix);
1603 sortcv_stacked(pTHX_ SV *a, SV *b)
1605 I32 oldsaveix = PL_savestack_ix;
1606 I32 oldscopeix = PL_scopestack_ix;
1610 av = GvAV(PL_defgv);
1612 if (AvMAX(av) < 1) {
1613 SV** ary = AvALLOC(av);
1614 if (AvARRAY(av) != ary) {
1615 AvMAX(av) += AvARRAY(av) - AvALLOC(av);
1616 SvPVX(av) = (char*)ary;
1618 if (AvMAX(av) < 1) {
1621 SvPVX(av) = (char*)ary;
1628 PL_stack_sp = PL_stack_base;
1631 if (PL_stack_sp != PL_stack_base + 1)
1632 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1633 if (!SvNIOKp(*PL_stack_sp))
1634 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1635 result = SvIV(*PL_stack_sp);
1636 while (PL_scopestack_ix > oldscopeix) {
1639 leave_scope(oldsaveix);
1644 sortcv_xsub(pTHX_ SV *a, SV *b)
1647 I32 oldsaveix = PL_savestack_ix;
1648 I32 oldscopeix = PL_scopestack_ix;
1650 CV *cv=(CV*)PL_sortcop;
1658 (void)(*CvXSUB(cv))(aTHX_ cv);
1659 if (PL_stack_sp != PL_stack_base + 1)
1660 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1661 if (!SvNIOKp(*PL_stack_sp))
1662 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1663 result = SvIV(*PL_stack_sp);
1664 while (PL_scopestack_ix > oldscopeix) {
1667 leave_scope(oldsaveix);
1673 sv_ncmp(pTHX_ SV *a, SV *b)
1677 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0;
1681 sv_i_ncmp(pTHX_ SV *a, SV *b)
1685 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0;
1687 #define tryCALL_AMAGICbin(left,right,meth,svp) STMT_START { \
1689 if (PL_amagic_generation) { \
1690 if (SvAMAGIC(left)||SvAMAGIC(right))\
1691 *svp = amagic_call(left, \
1699 amagic_ncmp(pTHX_ register SV *a, register SV *b)
1702 tryCALL_AMAGICbin(a,b,ncmp,&tmpsv);
1707 I32 i = SvIVX(tmpsv);
1717 return sv_ncmp(aTHX_ a, b);
1721 amagic_i_ncmp(pTHX_ register SV *a, register SV *b)
1724 tryCALL_AMAGICbin(a,b,ncmp,&tmpsv);
1729 I32 i = SvIVX(tmpsv);
1739 return sv_i_ncmp(aTHX_ a, b);
1743 amagic_cmp(pTHX_ register SV *str1, register SV *str2)
1746 tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv);
1751 I32 i = SvIVX(tmpsv);
1761 return sv_cmp(str1, str2);
1765 amagic_cmp_locale(pTHX_ register SV *str1, register SV *str2)
1768 tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv);
1773 I32 i = SvIVX(tmpsv);
1783 return sv_cmp_locale(str1, str2);