3 * Copyright (c) 1991-2002, Larry Wall
5 * You may distribute under the terms of either the GNU General Public
6 * License or the Artistic License, as specified in the README file.
11 * ...they shuffled back towards the rear of the line. 'No, not at the
12 * rear!' the slave-driver shouted. 'Three files up. And stay there...
16 #define PERL_IN_PP_SORT_C
20 /* looks like 'small' is reserved word for WINCE (or somesuch)*/
24 static I32 sortcv(pTHX_ SV *a, SV *b);
25 static I32 sortcv_stacked(pTHX_ SV *a, SV *b);
26 static I32 sortcv_xsub(pTHX_ SV *a, SV *b);
27 static I32 sv_ncmp(pTHX_ SV *a, SV *b);
28 static I32 sv_i_ncmp(pTHX_ SV *a, SV *b);
29 static I32 amagic_ncmp(pTHX_ SV *a, SV *b);
30 static I32 amagic_i_ncmp(pTHX_ SV *a, SV *b);
31 static I32 amagic_cmp(pTHX_ SV *a, SV *b);
32 static I32 amagic_cmp_locale(pTHX_ SV *a, SV *b);
34 #define sv_cmp_static Perl_sv_cmp
35 #define sv_cmp_locale_static Perl_sv_cmp_locale
37 #define SORTHINTS(hintsv) \
38 (((hintsv) = GvSV(gv_fetchpv("sort::hints", GV_ADDMULTI, SVt_IV))), \
39 (SvIOK(hintsv) ? ((I32)SvIV(hintsv)) : 0))
42 #define SMALLSORT (200)
46 * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>.
48 * The original code was written in conjunction with BSD Computer Software
49 * Research Group at University of California, Berkeley.
51 * See also: "Optimistic Merge Sort" (SODA '92)
53 * The integration to Perl is by John P. Linderman <jpl@research.att.com>.
55 * The code can be distributed under the same terms as Perl itself.
60 typedef char * aptr; /* pointer for arithmetic on sizes */
61 typedef SV * gptr; /* pointers in our lists */
63 /* Binary merge internal sort, with a few special mods
64 ** for the special perl environment it now finds itself in.
66 ** Things that were once options have been hotwired
67 ** to values suitable for this use. In particular, we'll always
68 ** initialize looking for natural runs, we'll always produce stable
69 ** output, and we'll always do Peter McIlroy's binary merge.
72 /* Pointer types for arithmetic and storage and convenience casts */
74 #define APTR(P) ((aptr)(P))
75 #define GPTP(P) ((gptr *)(P))
76 #define GPPP(P) ((gptr **)(P))
79 /* byte offset from pointer P to (larger) pointer Q */
80 #define BYTEOFF(P, Q) (APTR(Q) - APTR(P))
82 #define PSIZE sizeof(gptr)
84 /* If PSIZE is power of 2, make PSHIFT that power, if that helps */
87 #define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT))
88 #define PNBYTE(N) ((N) << (PSHIFT))
89 #define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N)))
91 /* Leave optimization to compiler */
92 #define PNELEM(P, Q) (GPTP(Q) - GPTP(P))
93 #define PNBYTE(N) ((N) * (PSIZE))
94 #define PINDEX(P, N) (GPTP(P) + (N))
97 /* Pointer into other corresponding to pointer into this */
98 #define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P))
100 #define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim)
103 /* Runs are identified by a pointer in the auxilliary list.
104 ** The pointer is at the start of the list,
105 ** and it points to the start of the next list.
106 ** NEXT is used as an lvalue, too.
109 #define NEXT(P) (*GPPP(P))
112 /* PTHRESH is the minimum number of pairs with the same sense to justify
113 ** checking for a run and extending it. Note that PTHRESH counts PAIRS,
114 ** not just elements, so PTHRESH == 8 means a run of 16.
119 /* RTHRESH is the number of elements in a run that must compare low
120 ** to the low element from the opposing run before we justify
121 ** doing a binary rampup instead of single stepping.
122 ** In random input, N in a row low should only happen with
123 ** probability 2^(1-N), so we can risk that we are dealing
124 ** with orderly input without paying much when we aren't.
131 ** Overview of algorithm and variables.
132 ** The array of elements at list1 will be organized into runs of length 2,
133 ** or runs of length >= 2 * PTHRESH. We only try to form long runs when
134 ** PTHRESH adjacent pairs compare in the same way, suggesting overall order.
136 ** Unless otherwise specified, pair pointers address the first of two elements.
138 ** b and b+1 are a pair that compare with sense ``sense''.
139 ** b is the ``bottom'' of adjacent pairs that might form a longer run.
141 ** p2 parallels b in the list2 array, where runs are defined by
144 ** t represents the ``top'' of the adjacent pairs that might extend
145 ** the run beginning at b. Usually, t addresses a pair
146 ** that compares with opposite sense from (b,b+1).
147 ** However, it may also address a singleton element at the end of list1,
148 ** or it may be equal to ``last'', the first element beyond list1.
150 ** r addresses the Nth pair following b. If this would be beyond t,
151 ** we back it off to t. Only when r is less than t do we consider the
152 ** run long enough to consider checking.
154 ** q addresses a pair such that the pairs at b through q already form a run.
155 ** Often, q will equal b, indicating we only are sure of the pair itself.
156 ** However, a search on the previous cycle may have revealed a longer run,
157 ** so q may be greater than b.
159 ** p is used to work back from a candidate r, trying to reach q,
160 ** which would mean b through r would be a run. If we discover such a run,
161 ** we start q at r and try to push it further towards t.
162 ** If b through r is NOT a run, we detect the wrong order at (p-1,p).
163 ** In any event, after the check (if any), we have two main cases.
165 ** 1) Short run. b <= q < p <= r <= t.
166 ** b through q is a run (perhaps trivial)
167 ** q through p are uninteresting pairs
168 ** p through r is a run
170 ** 2) Long run. b < r <= q < t.
171 ** b through q is a run (of length >= 2 * PTHRESH)
173 ** Note that degenerate cases are not only possible, but likely.
174 ** For example, if the pair following b compares with opposite sense,
175 ** then b == q < p == r == t.
180 dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, SVCOMPARE_t cmp)
183 register gptr *b, *p, *q, *t, *p2;
184 register gptr c, *last, *r;
189 last = PINDEX(b, nmemb);
190 sense = (cmp(aTHX_ *b, *(b+1)) > 0);
191 for (p2 = list2; b < last; ) {
192 /* We just started, or just reversed sense.
193 ** Set t at end of pairs with the prevailing sense.
195 for (p = b+2, t = p; ++p < last; t = ++p) {
196 if ((cmp(aTHX_ *t, *p) > 0) != sense) break;
199 /* Having laid out the playing field, look for long runs */
201 p = r = b + (2 * PTHRESH);
202 if (r >= t) p = r = t; /* too short to care about */
204 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) &&
207 /* b through r is a (long) run.
208 ** Extend it as far as possible.
211 while (((p += 2) < t) &&
212 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p;
213 r = p = q + 2; /* no simple pairs, no after-run */
216 if (q > b) { /* run of greater than 2 at b */
219 /* pick up singleton, if possible */
222 ((cmp(aTHX_ *(p-1), *p) > 0) == sense))
223 savep = r = p = q = last;
224 p2 = NEXT(p2) = p2 + (p - b); ++runs;
225 if (sense) while (b < --p) {
232 while (q < p) { /* simple pairs */
233 p2 = NEXT(p2) = p2 + 2; ++runs;
240 if (((b = p) == t) && ((t+1) == last)) {
241 NEXT(p2) = p2 + 1; ++runs;
252 /* The original merge sort, in use since 5.7, was as fast as, or faster than,
253 * qsort on many platforms, but slower than qsort, conspicuously so,
254 * on others. The most likely explanation was platform-specific
255 * differences in cache sizes and relative speeds.
257 * The quicksort divide-and-conquer algorithm guarantees that, as the
258 * problem is subdivided into smaller and smaller parts, the parts
259 * fit into smaller (and faster) caches. So it doesn't matter how
260 * many levels of cache exist, quicksort will "find" them, and,
261 * as long as smaller is faster, take advanatge of them.
263 * By contrast, consider how the original mergesort algorithm worked.
264 * Suppose we have five runs (each typically of length 2 after dynprep).
273 * Adjacent pairs are merged in "grand sweeps" through the input.
274 * This means, on pass 1, the records in runs 1 and 2 aren't revisited until
275 * runs 3 and 4 are merged and the runs from run 5 have been copied.
276 * The only cache that matters is one large enough to hold *all* the input.
277 * On some platforms, this may be many times slower than smaller caches.
279 * The following pseudo-code uses the same basic merge algorithm,
280 * but in a divide-and-conquer way.
282 * # merge $runs runs at offset $offset of list $list1 into $list2.
283 * # all unmerged runs ($runs == 1) originate in list $base.
285 * my ($offset, $runs, $base, $list1, $list2) = @_;
288 * if ($list1 is $base) copy run to $list2
289 * return offset of end of list (or copy)
291 * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1)
292 * mgsort2($off2, $runs/2, $base, $list2, $list1)
293 * merge the adjacent runs at $offset of $list1 into $list2
294 * return the offset of the end of the merged runs
297 * mgsort2(0, $runs, $base, $aux, $base);
299 * For our 5 runs, the tree of calls looks like
308 * and the corresponding activity looks like
310 * copy runs 1 and 2 from base to aux
311 * merge runs 1 and 2 from aux to base
312 * (run 3 is where it belongs, no copy needed)
313 * merge runs 12 and 3 from base to aux
314 * (runs 4 and 5 are where they belong, no copy needed)
315 * merge runs 4 and 5 from base to aux
316 * merge runs 123 and 45 from aux to base
318 * Note that we merge runs 1 and 2 immediately after copying them,
319 * while they are still likely to be in fast cache. Similarly,
320 * run 3 is merged with run 12 while it still may be lingering in cache.
321 * This implementation should therefore enjoy much of the cache-friendly
322 * behavior that quicksort does. In addition, it does less copying
323 * than the original mergesort implementation (only runs 1 and 2 are copied)
324 * and the "balancing" of merges is better (merged runs comprise more nearly
325 * equal numbers of original runs).
327 * The actual cache-friendly implementation will use a pseudo-stack
328 * to avoid recursion, and will unroll processing of runs of length 2,
329 * but it is otherwise similar to the recursive implementation.
333 IV offset; /* offset of 1st of 2 runs at this level */
334 IV runs; /* how many runs must be combined into 1 */
335 } off_runs; /* pseudo-stack element */
338 S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp)
340 IV i, run, runs, offset;
343 register gptr *f1, *f2, *t, *b, *p, *tp2, *l1, *l2, *q;
344 gptr *aux, *list1, *list2;
346 gptr small[SMALLSORT];
348 off_runs stack[60], *stackp;
350 if (nmemb <= 1) return; /* sorted trivially */
351 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */
352 else { New(799,aux,nmemb,gptr); } /* allocate auxilliary array */
355 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp);
356 stackp->offset = offset = 0;
357 which[0] = which[2] = base;
360 /* On levels where both runs have be constructed (stackp->runs == 0),
361 * merge them, and note the offset of their end, in case the offset
362 * is needed at the next level up. Hop up a level, and,
363 * as long as stackp->runs is 0, keep merging.
365 if ((runs = stackp->runs) == 0) {
367 list1 = which[iwhich]; /* area where runs are now */
368 list2 = which[++iwhich]; /* area for merged runs */
370 offset = stackp->offset;
371 f1 = p1 = list1 + offset; /* start of first run */
372 p = tp2 = list2 + offset; /* where merged run will go */
373 t = NEXT(p); /* where first run ends */
374 f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */
375 t = NEXT(t); /* where second runs ends */
376 l2 = POTHER(t, list2, list1); /* ... on the other side */
377 offset = PNELEM(list2, t);
378 while (f1 < l1 && f2 < l2) {
379 /* If head 1 is larger than head 2, find ALL the elements
380 ** in list 2 strictly less than head1, write them all,
381 ** then head 1. Then compare the new heads, and repeat,
382 ** until one or both lists are exhausted.
384 ** In all comparisons (after establishing
385 ** which head to merge) the item to merge
386 ** (at pointer q) is the first operand of
387 ** the comparison. When we want to know
388 ** if ``q is strictly less than the other'',
391 ** because stability demands that we treat equality
392 ** as high when q comes from l2, and as low when
393 ** q was from l1. So we ask the question by doing
394 ** cmp(q, other) <= sense
395 ** and make sense == 0 when equality should look low,
396 ** and -1 when equality should look high.
400 if (cmp(aTHX_ *f1, *f2) <= 0) {
401 q = f2; b = f1; t = l1;
404 q = f1; b = f2; t = l2;
411 ** Leave t at something strictly
412 ** greater than q (or at the end of the list),
413 ** and b at something strictly less than q.
415 for (i = 1, run = 0 ;;) {
416 if ((p = PINDEX(b, i)) >= t) {
418 if (((p = PINDEX(t, -1)) > b) &&
419 (cmp(aTHX_ *q, *p) <= sense))
423 } else if (cmp(aTHX_ *q, *p) <= sense) {
427 if (++run >= RTHRESH) i += i;
431 /* q is known to follow b and must be inserted before t.
432 ** Increment b, so the range of possibilities is [b,t).
433 ** Round binary split down, to favor early appearance.
434 ** Adjust b and t until q belongs just before t.
439 p = PINDEX(b, (PNELEM(b, t) - 1) / 2);
440 if (cmp(aTHX_ *q, *p) <= sense) {
446 /* Copy all the strictly low elements */
449 FROMTOUPTO(f2, tp2, t);
452 FROMTOUPTO(f1, tp2, t);
458 /* Run out remaining list */
460 if (f2 < l2) FROMTOUPTO(f2, tp2, l2);
461 } else FROMTOUPTO(f1, tp2, l1);
462 p1 = NEXT(p1) = POTHER(tp2, list2, list1);
464 if (--level == 0) goto done;
466 t = list1; list1 = list2; list2 = t; /* swap lists */
467 } while ((runs = stackp->runs) == 0);
471 stackp->runs = 0; /* current run will finish level */
472 /* While there are more than 2 runs remaining,
473 * turn them into exactly 2 runs (at the "other" level),
474 * each made up of approximately half the runs.
475 * Stack the second half for later processing,
476 * and set about producing the first half now.
481 stackp->offset = offset;
482 runs -= stackp->runs = runs / 2;
484 /* We must construct a single run from 1 or 2 runs.
485 * All the original runs are in which[0] == base.
486 * The run we construct must end up in which[level&1].
490 /* Constructing a single run from a single run.
491 * If it's where it belongs already, there's nothing to do.
492 * Otherwise, copy it to where it belongs.
493 * A run of 1 is either a singleton at level 0,
494 * or the second half of a split 3. In neither event
495 * is it necessary to set offset. It will be set by the merge
496 * that immediately follows.
498 if (iwhich) { /* Belongs in aux, currently in base */
499 f1 = b = PINDEX(base, offset); /* where list starts */
500 f2 = PINDEX(aux, offset); /* where list goes */
501 t = NEXT(f2); /* where list will end */
502 offset = PNELEM(aux, t); /* offset thereof */
503 t = PINDEX(base, offset); /* where it currently ends */
504 FROMTOUPTO(f1, f2, t); /* copy */
505 NEXT(b) = t; /* set up parallel pointer */
506 } else if (level == 0) goto done; /* single run at level 0 */
508 /* Constructing a single run from two runs.
509 * The merge code at the top will do that.
510 * We need only make sure the two runs are in the "other" array,
511 * so they'll end up in the correct array after the merge.
515 stackp->offset = offset;
516 stackp->runs = 0; /* take care of both runs, trigger merge */
517 if (!iwhich) { /* Merged runs belong in aux, copy 1st */
518 f1 = b = PINDEX(base, offset); /* where first run starts */
519 f2 = PINDEX(aux, offset); /* where it will be copied */
520 t = NEXT(f2); /* where first run will end */
521 offset = PNELEM(aux, t); /* offset thereof */
522 p = PINDEX(base, offset); /* end of first run */
523 t = NEXT(t); /* where second run will end */
524 t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */
525 FROMTOUPTO(f1, f2, t); /* copy both runs */
526 NEXT(b) = p; /* paralled pointer for 1st */
527 NEXT(p) = t; /* ... and for second */
532 if (aux != small) Safefree(aux); /* free iff allocated */
537 * The quicksort implementation was derived from source code contributed
540 * NOTE: this code was derived from Tom Horsley's qsort replacement
541 * and should not be confused with the original code.
544 /* Copyright (C) Tom Horsley, 1997. All rights reserved.
546 Permission granted to distribute under the same terms as perl which are
549 This program is free software; you can redistribute it and/or modify
550 it under the terms of either:
552 a) the GNU General Public License as published by the Free
553 Software Foundation; either version 1, or (at your option) any
556 b) the "Artistic License" which comes with this Kit.
558 Details on the perl license can be found in the perl source code which
559 may be located via the www.perl.com web page.
561 This is the most wonderfulest possible qsort I can come up with (and
562 still be mostly portable) My (limited) tests indicate it consistently
563 does about 20% fewer calls to compare than does the qsort in the Visual
564 C++ library, other vendors may vary.
566 Some of the ideas in here can be found in "Algorithms" by Sedgewick,
567 others I invented myself (or more likely re-invented since they seemed
568 pretty obvious once I watched the algorithm operate for a while).
570 Most of this code was written while watching the Marlins sweep the Giants
571 in the 1997 National League Playoffs - no Braves fans allowed to use this
572 code (just kidding :-).
574 I realize that if I wanted to be true to the perl tradition, the only
575 comment in this file would be something like:
577 ...they shuffled back towards the rear of the line. 'No, not at the
578 rear!' the slave-driver shouted. 'Three files up. And stay there...
580 However, I really needed to violate that tradition just so I could keep
581 track of what happens myself, not to mention some poor fool trying to
582 understand this years from now :-).
585 /* ********************************************************** Configuration */
587 #ifndef QSORT_ORDER_GUESS
588 #define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */
591 /* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for
592 future processing - a good max upper bound is log base 2 of memory size
593 (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can
594 safely be smaller than that since the program is taking up some space and
595 most operating systems only let you grab some subset of contiguous
596 memory (not to mention that you are normally sorting data larger than
597 1 byte element size :-).
599 #ifndef QSORT_MAX_STACK
600 #define QSORT_MAX_STACK 32
603 /* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort.
604 Anything bigger and we use qsort. If you make this too small, the qsort
605 will probably break (or become less efficient), because it doesn't expect
606 the middle element of a partition to be the same as the right or left -
607 you have been warned).
609 #ifndef QSORT_BREAK_EVEN
610 #define QSORT_BREAK_EVEN 6
613 /* QSORT_PLAY_SAFE is the size of the largest partition we're willing
614 to go quadratic on. We innoculate larger partitions against
615 quadratic behavior by shuffling them before sorting. This is not
616 an absolute guarantee of non-quadratic behavior, but it would take
617 staggeringly bad luck to pick extreme elements as the pivot
618 from randomized data.
620 #ifndef QSORT_PLAY_SAFE
621 #define QSORT_PLAY_SAFE 255
624 /* ************************************************************* Data Types */
626 /* hold left and right index values of a partition waiting to be sorted (the
627 partition includes both left and right - right is NOT one past the end or
630 struct partition_stack_entry {
633 #ifdef QSORT_ORDER_GUESS
634 int qsort_break_even;
638 /* ******************************************************* Shorthand Macros */
640 /* Note that these macros will be used from inside the qsort function where
641 we happen to know that the variable 'elt_size' contains the size of an
642 array element and the variable 'temp' points to enough space to hold a
643 temp element and the variable 'array' points to the array being sorted
644 and 'compare' is the pointer to the compare routine.
646 Also note that there are very many highly architecture specific ways
647 these might be sped up, but this is simply the most generally portable
648 code I could think of.
651 /* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2
653 #define qsort_cmp(elt1, elt2) \
654 ((*compare)(aTHX_ array[elt1], array[elt2]))
656 #ifdef QSORT_ORDER_GUESS
657 #define QSORT_NOTICE_SWAP swapped++;
659 #define QSORT_NOTICE_SWAP
662 /* swaps contents of array elements elt1, elt2.
664 #define qsort_swap(elt1, elt2) \
667 temp = array[elt1]; \
668 array[elt1] = array[elt2]; \
669 array[elt2] = temp; \
672 /* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets
673 elt3 and elt3 gets elt1.
675 #define qsort_rotate(elt1, elt2, elt3) \
678 temp = array[elt1]; \
679 array[elt1] = array[elt2]; \
680 array[elt2] = array[elt3]; \
681 array[elt3] = temp; \
684 /* ************************************************************ Debug stuff */
691 return; /* good place to set a breakpoint */
694 #define qsort_assert(t) (void)( (t) || (break_here(), 0) )
701 int (*compare)(const void * elt1, const void * elt2),
702 int pc_left, int pc_right, int u_left, int u_right)
706 qsort_assert(pc_left <= pc_right);
707 qsort_assert(u_right < pc_left);
708 qsort_assert(pc_right < u_left);
709 for (i = u_right + 1; i < pc_left; ++i) {
710 qsort_assert(qsort_cmp(i, pc_left) < 0);
712 for (i = pc_left; i < pc_right; ++i) {
713 qsort_assert(qsort_cmp(i, pc_right) == 0);
715 for (i = pc_right + 1; i < u_left; ++i) {
716 qsort_assert(qsort_cmp(pc_right, i) < 0);
720 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \
721 doqsort_all_asserts(array, num_elts, elt_size, compare, \
722 PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT)
726 #define qsort_assert(t) ((void)0)
728 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0)
732 /* ****************************************************************** qsort */
734 STATIC void /* the standard unstable (u) quicksort (qsort) */
735 S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare)
739 struct partition_stack_entry partition_stack[QSORT_MAX_STACK];
740 int next_stack_entry = 0;
744 #ifdef QSORT_ORDER_GUESS
745 int qsort_break_even;
749 /* Make sure we actually have work to do.
755 /* Innoculate large partitions against quadratic behavior */
756 if (num_elts > QSORT_PLAY_SAFE) {
757 register size_t n, j;
759 for (n = num_elts, q = array; n > 1; ) {
760 j = (size_t)(n-- * Drand01());
767 /* Setup the initial partition definition and fall into the sorting loop
770 part_right = (int)(num_elts - 1);
771 #ifdef QSORT_ORDER_GUESS
772 qsort_break_even = QSORT_BREAK_EVEN;
774 #define qsort_break_even QSORT_BREAK_EVEN
777 if ((part_right - part_left) >= qsort_break_even) {
778 /* OK, this is gonna get hairy, so lets try to document all the
779 concepts and abbreviations and variables and what they keep
782 pc: pivot chunk - the set of array elements we accumulate in the
783 middle of the partition, all equal in value to the original
784 pivot element selected. The pc is defined by:
786 pc_left - the leftmost array index of the pc
787 pc_right - the rightmost array index of the pc
789 we start with pc_left == pc_right and only one element
790 in the pivot chunk (but it can grow during the scan).
792 u: uncompared elements - the set of elements in the partition
793 we have not yet compared to the pivot value. There are two
794 uncompared sets during the scan - one to the left of the pc
795 and one to the right.
797 u_right - the rightmost index of the left side's uncompared set
798 u_left - the leftmost index of the right side's uncompared set
800 The leftmost index of the left sides's uncompared set
801 doesn't need its own variable because it is always defined
802 by the leftmost edge of the whole partition (part_left). The
803 same goes for the rightmost edge of the right partition
806 We know there are no uncompared elements on the left once we
807 get u_right < part_left and no uncompared elements on the
808 right once u_left > part_right. When both these conditions
809 are met, we have completed the scan of the partition.
811 Any elements which are between the pivot chunk and the
812 uncompared elements should be less than the pivot value on
813 the left side and greater than the pivot value on the right
814 side (in fact, the goal of the whole algorithm is to arrange
815 for that to be true and make the groups of less-than and
816 greater-then elements into new partitions to sort again).
818 As you marvel at the complexity of the code and wonder why it
819 has to be so confusing. Consider some of the things this level
822 Once I do a compare, I squeeze every ounce of juice out of it. I
823 never do compare calls I don't have to do, and I certainly never
826 I also never swap any elements unless I can prove there is a
827 good reason. Many sort algorithms will swap a known value with
828 an uncompared value just to get things in the right place (or
829 avoid complexity :-), but that uncompared value, once it gets
830 compared, may then have to be swapped again. A lot of the
831 complexity of this code is due to the fact that it never swaps
832 anything except compared values, and it only swaps them when the
833 compare shows they are out of position.
835 int pc_left, pc_right;
840 pc_left = ((part_left + part_right) / 2);
842 u_right = pc_left - 1;
843 u_left = pc_right + 1;
845 /* Qsort works best when the pivot value is also the median value
846 in the partition (unfortunately you can't find the median value
847 without first sorting :-), so to give the algorithm a helping
848 hand, we pick 3 elements and sort them and use the median value
849 of that tiny set as the pivot value.
851 Some versions of qsort like to use the left middle and right as
852 the 3 elements to sort so they can insure the ends of the
853 partition will contain values which will stop the scan in the
854 compare loop, but when you have to call an arbitrarily complex
855 routine to do a compare, its really better to just keep track of
856 array index values to know when you hit the edge of the
857 partition and avoid the extra compare. An even better reason to
858 avoid using a compare call is the fact that you can drop off the
859 edge of the array if someone foolishly provides you with an
860 unstable compare function that doesn't always provide consistent
863 So, since it is simpler for us to compare the three adjacent
864 elements in the middle of the partition, those are the ones we
865 pick here (conveniently pointed at by u_right, pc_left, and
866 u_left). The values of the left, center, and right elements
867 are refered to as l c and r in the following comments.
870 #ifdef QSORT_ORDER_GUESS
873 s = qsort_cmp(u_right, pc_left);
876 s = qsort_cmp(pc_left, u_left);
877 /* if l < c, c < r - already in order - nothing to do */
879 /* l < c, c == r - already in order, pc grows */
881 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
883 /* l < c, c > r - need to know more */
884 s = qsort_cmp(u_right, u_left);
886 /* l < c, c > r, l < r - swap c & r to get ordered */
887 qsort_swap(pc_left, u_left);
888 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
890 /* l < c, c > r, l == r - swap c&r, grow pc */
891 qsort_swap(pc_left, u_left);
893 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
895 /* l < c, c > r, l > r - make lcr into rlc to get ordered */
896 qsort_rotate(pc_left, u_right, u_left);
897 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
902 s = qsort_cmp(pc_left, u_left);
904 /* l == c, c < r - already in order, grow pc */
906 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
908 /* l == c, c == r - already in order, grow pc both ways */
911 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
913 /* l == c, c > r - swap l & r, grow pc */
914 qsort_swap(u_right, u_left);
916 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
920 s = qsort_cmp(pc_left, u_left);
922 /* l > c, c < r - need to know more */
923 s = qsort_cmp(u_right, u_left);
925 /* l > c, c < r, l < r - swap l & c to get ordered */
926 qsort_swap(u_right, pc_left);
927 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
929 /* l > c, c < r, l == r - swap l & c, grow pc */
930 qsort_swap(u_right, pc_left);
932 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
934 /* l > c, c < r, l > r - rotate lcr into crl to order */
935 qsort_rotate(u_right, pc_left, u_left);
936 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
939 /* l > c, c == r - swap ends, grow pc */
940 qsort_swap(u_right, u_left);
942 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
944 /* l > c, c > r - swap ends to get in order */
945 qsort_swap(u_right, u_left);
946 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1);
949 /* We now know the 3 middle elements have been compared and
950 arranged in the desired order, so we can shrink the uncompared
955 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
957 /* The above massive nested if was the simple part :-). We now have
958 the middle 3 elements ordered and we need to scan through the
959 uncompared sets on either side, swapping elements that are on
960 the wrong side or simply shuffling equal elements around to get
961 all equal elements into the pivot chunk.
965 int still_work_on_left;
966 int still_work_on_right;
968 /* Scan the uncompared values on the left. If I find a value
969 equal to the pivot value, move it over so it is adjacent to
970 the pivot chunk and expand the pivot chunk. If I find a value
971 less than the pivot value, then just leave it - its already
972 on the correct side of the partition. If I find a greater
973 value, then stop the scan.
975 while ((still_work_on_left = (u_right >= part_left))) {
976 s = qsort_cmp(u_right, pc_left);
981 if (pc_left != u_right) {
982 qsort_swap(u_right, pc_left);
988 qsort_assert(u_right < pc_left);
989 qsort_assert(pc_left <= pc_right);
990 qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0);
991 qsort_assert(qsort_cmp(pc_left, pc_right) == 0);
994 /* Do a mirror image scan of uncompared values on the right
996 while ((still_work_on_right = (u_left <= part_right))) {
997 s = qsort_cmp(pc_right, u_left);
1000 } else if (s == 0) {
1002 if (pc_right != u_left) {
1003 qsort_swap(pc_right, u_left);
1009 qsort_assert(u_left > pc_right);
1010 qsort_assert(pc_left <= pc_right);
1011 qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0);
1012 qsort_assert(qsort_cmp(pc_left, pc_right) == 0);
1015 if (still_work_on_left) {
1016 /* I know I have a value on the left side which needs to be
1017 on the right side, but I need to know more to decide
1018 exactly the best thing to do with it.
1020 if (still_work_on_right) {
1021 /* I know I have values on both side which are out of
1022 position. This is a big win because I kill two birds
1023 with one swap (so to speak). I can advance the
1024 uncompared pointers on both sides after swapping both
1025 of them into the right place.
1027 qsort_swap(u_right, u_left);
1030 qsort_all_asserts(pc_left, pc_right, u_left, u_right);
1032 /* I have an out of position value on the left, but the
1033 right is fully scanned, so I "slide" the pivot chunk
1034 and any less-than values left one to make room for the
1035 greater value over on the right. If the out of position
1036 value is immediately adjacent to the pivot chunk (there
1037 are no less-than values), I can do that with a swap,
1038 otherwise, I have to rotate one of the less than values
1039 into the former position of the out of position value
1040 and the right end of the pivot chunk into the left end
1044 if (pc_left == u_right) {
1045 qsort_swap(u_right, pc_right);
1046 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
1048 qsort_rotate(u_right, pc_left, pc_right);
1049 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1);
1054 } else if (still_work_on_right) {
1055 /* Mirror image of complex case above: I have an out of
1056 position value on the right, but the left is fully
1057 scanned, so I need to shuffle things around to make room
1058 for the right value on the left.
1061 if (pc_right == u_left) {
1062 qsort_swap(u_left, pc_left);
1063 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1065 qsort_rotate(pc_right, pc_left, u_left);
1066 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right);
1071 /* No more scanning required on either side of partition,
1072 break out of loop and figure out next set of partitions
1078 /* The elements in the pivot chunk are now in the right place. They
1079 will never move or be compared again. All I have to do is decide
1080 what to do with the stuff to the left and right of the pivot
1083 Notes on the QSORT_ORDER_GUESS ifdef code:
1085 1. If I just built these partitions without swapping any (or
1086 very many) elements, there is a chance that the elements are
1087 already ordered properly (being properly ordered will
1088 certainly result in no swapping, but the converse can't be
1091 2. A (properly written) insertion sort will run faster on
1092 already ordered data than qsort will.
1094 3. Perhaps there is some way to make a good guess about
1095 switching to an insertion sort earlier than partition size 6
1096 (for instance - we could save the partition size on the stack
1097 and increase the size each time we find we didn't swap, thus
1098 switching to insertion sort earlier for partitions with a
1099 history of not swapping).
1101 4. Naturally, if I just switch right away, it will make
1102 artificial benchmarks with pure ascending (or descending)
1103 data look really good, but is that a good reason in general?
1107 #ifdef QSORT_ORDER_GUESS
1109 #if QSORT_ORDER_GUESS == 1
1110 qsort_break_even = (part_right - part_left) + 1;
1112 #if QSORT_ORDER_GUESS == 2
1113 qsort_break_even *= 2;
1115 #if QSORT_ORDER_GUESS == 3
1116 int prev_break = qsort_break_even;
1117 qsort_break_even *= qsort_break_even;
1118 if (qsort_break_even < prev_break) {
1119 qsort_break_even = (part_right - part_left) + 1;
1123 qsort_break_even = QSORT_BREAK_EVEN;
1127 if (part_left < pc_left) {
1128 /* There are elements on the left which need more processing.
1129 Check the right as well before deciding what to do.
1131 if (pc_right < part_right) {
1132 /* We have two partitions to be sorted. Stack the biggest one
1133 and process the smallest one on the next iteration. This
1134 minimizes the stack height by insuring that any additional
1135 stack entries must come from the smallest partition which
1136 (because it is smallest) will have the fewest
1137 opportunities to generate additional stack entries.
1139 if ((part_right - pc_right) > (pc_left - part_left)) {
1140 /* stack the right partition, process the left */
1141 partition_stack[next_stack_entry].left = pc_right + 1;
1142 partition_stack[next_stack_entry].right = part_right;
1143 #ifdef QSORT_ORDER_GUESS
1144 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even;
1146 part_right = pc_left - 1;
1148 /* stack the left partition, process the right */
1149 partition_stack[next_stack_entry].left = part_left;
1150 partition_stack[next_stack_entry].right = pc_left - 1;
1151 #ifdef QSORT_ORDER_GUESS
1152 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even;
1154 part_left = pc_right + 1;
1156 qsort_assert(next_stack_entry < QSORT_MAX_STACK);
1159 /* The elements on the left are the only remaining elements
1160 that need sorting, arrange for them to be processed as the
1163 part_right = pc_left - 1;
1165 } else if (pc_right < part_right) {
1166 /* There is only one chunk on the right to be sorted, make it
1167 the new partition and loop back around.
1169 part_left = pc_right + 1;
1171 /* This whole partition wound up in the pivot chunk, so
1172 we need to get a new partition off the stack.
1174 if (next_stack_entry == 0) {
1175 /* the stack is empty - we are done */
1179 part_left = partition_stack[next_stack_entry].left;
1180 part_right = partition_stack[next_stack_entry].right;
1181 #ifdef QSORT_ORDER_GUESS
1182 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even;
1186 /* This partition is too small to fool with qsort complexity, just
1187 do an ordinary insertion sort to minimize overhead.
1190 /* Assume 1st element is in right place already, and start checking
1191 at 2nd element to see where it should be inserted.
1193 for (i = part_left + 1; i <= part_right; ++i) {
1195 /* Scan (backwards - just in case 'i' is already in right place)
1196 through the elements already sorted to see if the ith element
1197 belongs ahead of one of them.
1199 for (j = i - 1; j >= part_left; --j) {
1200 if (qsort_cmp(i, j) >= 0) {
1201 /* i belongs right after j
1208 /* Looks like we really need to move some things
1212 for (k = i - 1; k >= j; --k)
1213 array[k + 1] = array[k];
1218 /* That partition is now sorted, grab the next one, or get out
1219 of the loop if there aren't any more.
1222 if (next_stack_entry == 0) {
1223 /* the stack is empty - we are done */
1227 part_left = partition_stack[next_stack_entry].left;
1228 part_right = partition_stack[next_stack_entry].right;
1229 #ifdef QSORT_ORDER_GUESS
1230 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even;
1235 /* Believe it or not, the array is sorted at this point! */
1238 /* Stabilize what is, presumably, an otherwise unstable sort method.
1239 * We do that by allocating (or having on hand) an array of pointers
1240 * that is the same size as the original array of elements to be sorted.
1241 * We initialize this parallel array with the addresses of the original
1242 * array elements. This indirection can make you crazy.
1243 * Some pictures can help. After initializing, we have
1247 * | | --------------> | | ------> first element to be sorted
1249 * | | --------------> | | ------> second element to be sorted
1251 * | | --------------> | | ------> third element to be sorted
1255 * | | --------------> | | ------> n-1st element to be sorted
1257 * | | --------------> | | ------> n-th element to be sorted
1260 * During the sort phase, we leave the elements of list1 where they are,
1261 * and sort the pointers in the indirect array in the same order determined
1262 * by the original comparison routine on the elements pointed to.
1263 * Because we don't move the elements of list1 around through
1264 * this phase, we can break ties on elements that compare equal
1265 * using their address in the list1 array, ensuring stabilty.
1266 * This leaves us with something looking like
1270 * | | --+ +---> | | ------> first element to be sorted
1272 * | | --|-------|---> | | ------> second element to be sorted
1274 * | | --|-------+ +-> | | ------> third element to be sorted
1277 * +----+ | | | | +----+
1278 * | | ---|-+ | +--> | | ------> n-1st element to be sorted
1280 * | | ---+ +----> | | ------> n-th element to be sorted
1283 * where the i-th element of the indirect array points to the element
1284 * that should be i-th in the sorted array. After the sort phase,
1285 * we have to put the elements of list1 into the places
1286 * dictated by the indirect array.
1291 cmpindir(pTHX_ gptr a, gptr b)
1294 gptr *ap = (gptr *)a;
1295 gptr *bp = (gptr *)b;
1297 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)) == 0)
1298 sense = (ap > bp) ? 1 : ((ap < bp) ? -1 : 0);
1303 S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp)
1307 if (SORTHINTS(hintsv) & HINT_SORT_STABLE) {
1308 register gptr **pp, *q;
1309 register size_t n, j, i;
1310 gptr *small[SMALLSORT], **indir, tmp;
1311 SVCOMPARE_t savecmp;
1312 if (nmemb <= 1) return; /* sorted trivially */
1314 /* Small arrays can use the stack, big ones must be allocated */
1315 if (nmemb <= SMALLSORT) indir = small;
1316 else { New(1799, indir, nmemb, gptr *); }
1318 /* Copy pointers to original array elements into indirect array */
1319 for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++;
1321 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */
1322 PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */
1324 /* sort, with indirection */
1325 S_qsortsvu(aTHX_ (gptr *)indir, nmemb, cmpindir);
1329 for (n = nmemb; n--; ) {
1330 /* Assert A: all elements of q with index > n are already
1331 * in place. This is vacuosly true at the start, and we
1332 * put element n where it belongs below (if it wasn't
1333 * already where it belonged). Assert B: we only move
1334 * elements that aren't where they belong,
1335 * so, by A, we never tamper with elements above n.
1337 j = pp[n] - q; /* This sets j so that q[j] is
1338 * at pp[n]. *pp[j] belongs in
1339 * q[j], by construction.
1341 if (n != j) { /* all's well if n == j */
1342 tmp = q[j]; /* save what's in q[j] */
1344 q[j] = *pp[j]; /* put *pp[j] where it belongs */
1345 i = pp[j] - q; /* the index in q of the element
1347 pp[j] = q + j; /* this is ok now */
1348 } while ((j = i) != n);
1349 /* There are only finitely many (nmemb) addresses
1351 * So we must eventually revisit an index we saw before.
1352 * Suppose the first revisited index is k != n.
1353 * An index is visited because something else belongs there.
1354 * If we visit k twice, then two different elements must
1355 * belong in the same place, which cannot be.
1356 * So j must get back to n, the loop terminates,
1357 * and we put the saved element where it belongs.
1359 q[n] = tmp; /* put what belongs into
1360 * the n-th element */
1364 /* free iff allocated */
1365 if (indir != small) { Safefree(indir); }
1366 /* restore prevailing comparison routine */
1367 PL_sort_RealCmp = savecmp;
1369 S_qsortsvu(aTHX_ list1, nmemb, cmp);
1374 =head1 Array Manipulation Functions
1378 Sort an array. Here is an example:
1380 sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);
1382 See lib/sort.pm for details about controlling the sorting algorithm.
1388 Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp)
1390 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) =
1395 /* Sun's Compiler (cc: WorkShop Compilers 4.2 30 Oct 1996 C 4.2) used
1396 to miscompile this function under optimization -O. If you get test
1397 errors related to picking the correct sort() function, try recompiling
1398 this file without optimiziation. -- A.D. 4/2002.
1400 hints = SORTHINTS(hintsv);
1401 if (hints & HINT_SORT_QUICKSORT) {
1402 sortsvp = S_qsortsv;
1405 /* The default as of 5.8.0 is mergesort */
1406 sortsvp = S_mergesortsv;
1409 sortsvp(aTHX_ array, nmemb, cmp);
1414 dSP; dMARK; dORIGMARK;
1416 SV **myorigmark = ORIGMARK;
1422 OP* nextop = PL_op->op_next;
1423 I32 overloading = 0;
1424 bool hasargs = FALSE;
1427 if (gimme != G_ARRAY) {
1433 SAVEVPTR(PL_sortcop);
1434 if (PL_op->op_flags & OPf_STACKED) {
1435 if (PL_op->op_flags & OPf_SPECIAL) {
1436 OP *kid = cLISTOP->op_first->op_sibling; /* pass pushmark */
1437 kid = kUNOP->op_first; /* pass rv2gv */
1438 kid = kUNOP->op_first; /* pass leave */
1439 PL_sortcop = kid->op_next;
1440 stash = CopSTASH(PL_curcop);
1443 cv = sv_2cv(*++MARK, &stash, &gv, 0);
1444 if (cv && SvPOK(cv)) {
1446 char *proto = SvPV((SV*)cv, n_a);
1447 if (proto && strEQ(proto, "$$")) {
1451 if (!(cv && CvROOT(cv))) {
1452 if (cv && CvXSUB(cv)) {
1456 SV *tmpstr = sv_newmortal();
1457 gv_efullname3(tmpstr, gv, Nullch);
1458 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called",
1462 DIE(aTHX_ "Undefined subroutine in sort");
1467 PL_sortcop = (OP*)cv;
1469 PL_sortcop = CvSTART(cv);
1470 SAVEVPTR(CvROOT(cv)->op_ppaddr);
1471 CvROOT(cv)->op_ppaddr = PL_ppaddr[OP_NULL];
1473 PAD_SET_CUR(CvPADLIST(cv), 1);
1478 PL_sortcop = Nullop;
1479 stash = CopSTASH(PL_curcop);
1482 up = myorigmark + 1;
1483 while (MARK < SP) { /* This may or may not shift down one here. */
1485 if ((*up = *++MARK)) { /* Weed out nulls. */
1487 if (!PL_sortcop && !SvPOK(*up)) {
1492 (void)sv_2pv(*up, &n_a);
1497 max = --up - myorigmark;
1502 bool oldcatch = CATCH_GET;
1508 PUSHSTACKi(PERLSI_SORT);
1509 if (!hasargs && !is_xsub) {
1510 if (PL_sortstash != stash || !PL_firstgv || !PL_secondgv) {
1511 SAVESPTR(PL_firstgv);
1512 SAVESPTR(PL_secondgv);
1513 PL_firstgv = gv_fetchpv("a", TRUE, SVt_PV);
1514 PL_secondgv = gv_fetchpv("b", TRUE, SVt_PV);
1515 PL_sortstash = stash;
1517 SAVESPTR(GvSV(PL_firstgv));
1518 SAVESPTR(GvSV(PL_secondgv));
1521 PUSHBLOCK(cx, CXt_NULL, PL_stack_base);
1522 if (!(PL_op->op_flags & OPf_SPECIAL)) {
1523 cx->cx_type = CXt_SUB;
1524 cx->blk_gimme = G_SCALAR;
1527 (void)SvREFCNT_inc(cv); /* in preparation for POPSUB */
1529 PL_sortcxix = cxstack_ix;
1531 if (hasargs && !is_xsub) {
1532 /* This is mostly copied from pp_entersub */
1533 AV *av = (AV*)PAD_SVl(0);
1535 cx->blk_sub.savearray = GvAV(PL_defgv);
1536 GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av);
1537 CX_CURPAD_SAVE(cx->blk_sub);
1538 cx->blk_sub.argarray = av;
1540 sortsv((myorigmark+1), max,
1541 is_xsub ? sortcv_xsub : hasargs ? sortcv_stacked : sortcv);
1543 POPBLOCK(cx,PL_curpm);
1544 PL_stack_sp = newsp;
1546 CATCH_SET(oldcatch);
1551 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */
1552 sortsv(ORIGMARK+1, max,
1553 (PL_op->op_private & OPpSORT_NUMERIC)
1554 ? ( (PL_op->op_private & OPpSORT_INTEGER)
1555 ? ( overloading ? amagic_i_ncmp : sv_i_ncmp)
1556 : ( overloading ? amagic_ncmp : sv_ncmp))
1557 : ( IN_LOCALE_RUNTIME
1560 : sv_cmp_locale_static)
1561 : ( overloading ? amagic_cmp : sv_cmp_static)));
1562 if (PL_op->op_private & OPpSORT_REVERSE) {
1563 SV **p = ORIGMARK+1;
1564 SV **q = ORIGMARK+max;
1574 PL_stack_sp = ORIGMARK + max;
1579 sortcv(pTHX_ SV *a, SV *b)
1581 I32 oldsaveix = PL_savestack_ix;
1582 I32 oldscopeix = PL_scopestack_ix;
1584 GvSV(PL_firstgv) = a;
1585 GvSV(PL_secondgv) = b;
1586 PL_stack_sp = PL_stack_base;
1589 if (PL_stack_sp != PL_stack_base + 1)
1590 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1591 if (!SvNIOKp(*PL_stack_sp))
1592 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1593 result = SvIV(*PL_stack_sp);
1594 while (PL_scopestack_ix > oldscopeix) {
1597 leave_scope(oldsaveix);
1602 sortcv_stacked(pTHX_ SV *a, SV *b)
1604 I32 oldsaveix = PL_savestack_ix;
1605 I32 oldscopeix = PL_scopestack_ix;
1609 av = GvAV(PL_defgv);
1611 if (AvMAX(av) < 1) {
1612 SV** ary = AvALLOC(av);
1613 if (AvARRAY(av) != ary) {
1614 AvMAX(av) += AvARRAY(av) - AvALLOC(av);
1615 SvPVX(av) = (char*)ary;
1617 if (AvMAX(av) < 1) {
1620 SvPVX(av) = (char*)ary;
1627 PL_stack_sp = PL_stack_base;
1630 if (PL_stack_sp != PL_stack_base + 1)
1631 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1632 if (!SvNIOKp(*PL_stack_sp))
1633 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1634 result = SvIV(*PL_stack_sp);
1635 while (PL_scopestack_ix > oldscopeix) {
1638 leave_scope(oldsaveix);
1643 sortcv_xsub(pTHX_ SV *a, SV *b)
1646 I32 oldsaveix = PL_savestack_ix;
1647 I32 oldscopeix = PL_scopestack_ix;
1649 CV *cv=(CV*)PL_sortcop;
1657 (void)(*CvXSUB(cv))(aTHX_ cv);
1658 if (PL_stack_sp != PL_stack_base + 1)
1659 Perl_croak(aTHX_ "Sort subroutine didn't return single value");
1660 if (!SvNIOKp(*PL_stack_sp))
1661 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value");
1662 result = SvIV(*PL_stack_sp);
1663 while (PL_scopestack_ix > oldscopeix) {
1666 leave_scope(oldsaveix);
1672 sv_ncmp(pTHX_ SV *a, SV *b)
1676 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0;
1680 sv_i_ncmp(pTHX_ SV *a, SV *b)
1684 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0;
1686 #define tryCALL_AMAGICbin(left,right,meth,svp) STMT_START { \
1688 if (PL_amagic_generation) { \
1689 if (SvAMAGIC(left)||SvAMAGIC(right))\
1690 *svp = amagic_call(left, \
1698 amagic_ncmp(pTHX_ register SV *a, register SV *b)
1701 tryCALL_AMAGICbin(a,b,ncmp,&tmpsv);
1706 I32 i = SvIVX(tmpsv);
1716 return sv_ncmp(aTHX_ a, b);
1720 amagic_i_ncmp(pTHX_ register SV *a, register SV *b)
1723 tryCALL_AMAGICbin(a,b,ncmp,&tmpsv);
1728 I32 i = SvIVX(tmpsv);
1738 return sv_i_ncmp(aTHX_ a, b);
1742 amagic_cmp(pTHX_ register SV *str1, register SV *str2)
1745 tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv);
1750 I32 i = SvIVX(tmpsv);
1760 return sv_cmp(str1, str2);
1764 amagic_cmp_locale(pTHX_ register SV *str1, register SV *str2)
1767 tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv);
1772 I32 i = SvIVX(tmpsv);
1782 return sv_cmp_locale(str1, str2);