Mercurial > repo
diff perl-5.22.2/pp_sort.c @ 8045:a16537d2fe07
<xfix> tar xf perl-5.22.2.tar.gz # Ah, whatever, I\'m doing it anyway
author | HackBot |
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date | Sat, 14 May 2016 14:54:38 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/perl-5.22.2/pp_sort.c Sat May 14 14:54:38 2016 +0000 @@ -0,0 +1,2019 @@ +/* pp_sort.c + * + * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, + * 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others + * + * You may distribute under the terms of either the GNU General Public + * License or the Artistic License, as specified in the README file. + * + */ + +/* + * ...they shuffled back towards the rear of the line. 'No, not at the + * rear!' the slave-driver shouted. 'Three files up. And stay there... + * + * [p.931 of _The Lord of the Rings_, VI/ii: "The Land of Shadow"] + */ + +/* This file contains pp ("push/pop") functions that + * execute the opcodes that make up a perl program. A typical pp function + * expects to find its arguments on the stack, and usually pushes its + * results onto the stack, hence the 'pp' terminology. Each OP structure + * contains a pointer to the relevant pp_foo() function. + * + * This particular file just contains pp_sort(), which is complex + * enough to merit its own file! See the other pp*.c files for the rest of + * the pp_ functions. + */ + +#include "EXTERN.h" +#define PERL_IN_PP_SORT_C +#include "perl.h" + +#if defined(UNDER_CE) +/* looks like 'small' is reserved word for WINCE (or somesuch)*/ +#define small xsmall +#endif + +#define sv_cmp_static Perl_sv_cmp +#define sv_cmp_locale_static Perl_sv_cmp_locale + +#ifndef SMALLSORT +#define SMALLSORT (200) +#endif + +/* Flags for qsortsv and mergesortsv */ +#define SORTf_DESC 1 +#define SORTf_STABLE 2 +#define SORTf_QSORT 4 + +/* + * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>. + * + * The original code was written in conjunction with BSD Computer Software + * Research Group at University of California, Berkeley. + * + * See also: "Optimistic Sorting and Information Theoretic Complexity" + * Peter McIlroy + * SODA (Fourth Annual ACM-SIAM Symposium on Discrete Algorithms), + * pp 467-474, Austin, Texas, 25-27 January 1993. + * + * The integration to Perl is by John P. Linderman <jpl.jpl@gmail.com>. + * + * The code can be distributed under the same terms as Perl itself. + * + */ + + +typedef char * aptr; /* pointer for arithmetic on sizes */ +typedef SV * gptr; /* pointers in our lists */ + +/* Binary merge internal sort, with a few special mods +** for the special perl environment it now finds itself in. +** +** Things that were once options have been hotwired +** to values suitable for this use. In particular, we'll always +** initialize looking for natural runs, we'll always produce stable +** output, and we'll always do Peter McIlroy's binary merge. +*/ + +/* Pointer types for arithmetic and storage and convenience casts */ + +#define APTR(P) ((aptr)(P)) +#define GPTP(P) ((gptr *)(P)) +#define GPPP(P) ((gptr **)(P)) + + +/* byte offset from pointer P to (larger) pointer Q */ +#define BYTEOFF(P, Q) (APTR(Q) - APTR(P)) + +#define PSIZE sizeof(gptr) + +/* If PSIZE is power of 2, make PSHIFT that power, if that helps */ + +#ifdef PSHIFT +#define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT)) +#define PNBYTE(N) ((N) << (PSHIFT)) +#define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N))) +#else +/* Leave optimization to compiler */ +#define PNELEM(P, Q) (GPTP(Q) - GPTP(P)) +#define PNBYTE(N) ((N) * (PSIZE)) +#define PINDEX(P, N) (GPTP(P) + (N)) +#endif + +/* Pointer into other corresponding to pointer into this */ +#define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P)) + +#define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim) + + +/* Runs are identified by a pointer in the auxiliary list. +** The pointer is at the start of the list, +** and it points to the start of the next list. +** NEXT is used as an lvalue, too. +*/ + +#define NEXT(P) (*GPPP(P)) + + +/* PTHRESH is the minimum number of pairs with the same sense to justify +** checking for a run and extending it. Note that PTHRESH counts PAIRS, +** not just elements, so PTHRESH == 8 means a run of 16. +*/ + +#define PTHRESH (8) + +/* RTHRESH is the number of elements in a run that must compare low +** to the low element from the opposing run before we justify +** doing a binary rampup instead of single stepping. +** In random input, N in a row low should only happen with +** probability 2^(1-N), so we can risk that we are dealing +** with orderly input without paying much when we aren't. +*/ + +#define RTHRESH (6) + + +/* +** Overview of algorithm and variables. +** The array of elements at list1 will be organized into runs of length 2, +** or runs of length >= 2 * PTHRESH. We only try to form long runs when +** PTHRESH adjacent pairs compare in the same way, suggesting overall order. +** +** Unless otherwise specified, pair pointers address the first of two elements. +** +** b and b+1 are a pair that compare with sense "sense". +** b is the "bottom" of adjacent pairs that might form a longer run. +** +** p2 parallels b in the list2 array, where runs are defined by +** a pointer chain. +** +** t represents the "top" of the adjacent pairs that might extend +** the run beginning at b. Usually, t addresses a pair +** that compares with opposite sense from (b,b+1). +** However, it may also address a singleton element at the end of list1, +** or it may be equal to "last", the first element beyond list1. +** +** r addresses the Nth pair following b. If this would be beyond t, +** we back it off to t. Only when r is less than t do we consider the +** run long enough to consider checking. +** +** q addresses a pair such that the pairs at b through q already form a run. +** Often, q will equal b, indicating we only are sure of the pair itself. +** However, a search on the previous cycle may have revealed a longer run, +** so q may be greater than b. +** +** p is used to work back from a candidate r, trying to reach q, +** which would mean b through r would be a run. If we discover such a run, +** we start q at r and try to push it further towards t. +** If b through r is NOT a run, we detect the wrong order at (p-1,p). +** In any event, after the check (if any), we have two main cases. +** +** 1) Short run. b <= q < p <= r <= t. +** b through q is a run (perhaps trivial) +** q through p are uninteresting pairs +** p through r is a run +** +** 2) Long run. b < r <= q < t. +** b through q is a run (of length >= 2 * PTHRESH) +** +** Note that degenerate cases are not only possible, but likely. +** For example, if the pair following b compares with opposite sense, +** then b == q < p == r == t. +*/ + + +static IV +dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, const SVCOMPARE_t cmp) +{ + I32 sense; + gptr *b, *p, *q, *t, *p2; + gptr *last, *r; + IV runs = 0; + + b = list1; + last = PINDEX(b, nmemb); + sense = (cmp(aTHX_ *b, *(b+1)) > 0); + for (p2 = list2; b < last; ) { + /* We just started, or just reversed sense. + ** Set t at end of pairs with the prevailing sense. + */ + for (p = b+2, t = p; ++p < last; t = ++p) { + if ((cmp(aTHX_ *t, *p) > 0) != sense) break; + } + q = b; + /* Having laid out the playing field, look for long runs */ + do { + p = r = b + (2 * PTHRESH); + if (r >= t) p = r = t; /* too short to care about */ + else { + while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) && + ((p -= 2) > q)) {} + if (p <= q) { + /* b through r is a (long) run. + ** Extend it as far as possible. + */ + p = q = r; + while (((p += 2) < t) && + ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p; + r = p = q + 2; /* no simple pairs, no after-run */ + } + } + if (q > b) { /* run of greater than 2 at b */ + gptr *savep = p; + + p = q += 2; + /* pick up singleton, if possible */ + if ((p == t) && + ((t + 1) == last) && + ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) + savep = r = p = q = last; + p2 = NEXT(p2) = p2 + (p - b); ++runs; + if (sense) + while (b < --p) { + const gptr c = *b; + *b++ = *p; + *p = c; + } + p = savep; + } + while (q < p) { /* simple pairs */ + p2 = NEXT(p2) = p2 + 2; ++runs; + if (sense) { + const gptr c = *q++; + *(q-1) = *q; + *q++ = c; + } else q += 2; + } + if (((b = p) == t) && ((t+1) == last)) { + NEXT(p2) = p2 + 1; ++runs; + b++; + } + q = r; + } while (b < t); + sense = !sense; + } + return runs; +} + + +/* The original merge sort, in use since 5.7, was as fast as, or faster than, + * qsort on many platforms, but slower than qsort, conspicuously so, + * on others. The most likely explanation was platform-specific + * differences in cache sizes and relative speeds. + * + * The quicksort divide-and-conquer algorithm guarantees that, as the + * problem is subdivided into smaller and smaller parts, the parts + * fit into smaller (and faster) caches. So it doesn't matter how + * many levels of cache exist, quicksort will "find" them, and, + * as long as smaller is faster, take advantage of them. + * + * By contrast, consider how the original mergesort algorithm worked. + * Suppose we have five runs (each typically of length 2 after dynprep). + * + * pass base aux + * 0 1 2 3 4 5 + * 1 12 34 5 + * 2 1234 5 + * 3 12345 + * 4 12345 + * + * Adjacent pairs are merged in "grand sweeps" through the input. + * This means, on pass 1, the records in runs 1 and 2 aren't revisited until + * runs 3 and 4 are merged and the runs from run 5 have been copied. + * The only cache that matters is one large enough to hold *all* the input. + * On some platforms, this may be many times slower than smaller caches. + * + * The following pseudo-code uses the same basic merge algorithm, + * but in a divide-and-conquer way. + * + * # merge $runs runs at offset $offset of list $list1 into $list2. + * # all unmerged runs ($runs == 1) originate in list $base. + * sub mgsort2 { + * my ($offset, $runs, $base, $list1, $list2) = @_; + * + * if ($runs == 1) { + * if ($list1 is $base) copy run to $list2 + * return offset of end of list (or copy) + * } else { + * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1) + * mgsort2($off2, $runs/2, $base, $list2, $list1) + * merge the adjacent runs at $offset of $list1 into $list2 + * return the offset of the end of the merged runs + * } + * } + * mgsort2(0, $runs, $base, $aux, $base); + * + * For our 5 runs, the tree of calls looks like + * + * 5 + * 3 2 + * 2 1 1 1 + * 1 1 + * + * 1 2 3 4 5 + * + * and the corresponding activity looks like + * + * copy runs 1 and 2 from base to aux + * merge runs 1 and 2 from aux to base + * (run 3 is where it belongs, no copy needed) + * merge runs 12 and 3 from base to aux + * (runs 4 and 5 are where they belong, no copy needed) + * merge runs 4 and 5 from base to aux + * merge runs 123 and 45 from aux to base + * + * Note that we merge runs 1 and 2 immediately after copying them, + * while they are still likely to be in fast cache. Similarly, + * run 3 is merged with run 12 while it still may be lingering in cache. + * This implementation should therefore enjoy much of the cache-friendly + * behavior that quicksort does. In addition, it does less copying + * than the original mergesort implementation (only runs 1 and 2 are copied) + * and the "balancing" of merges is better (merged runs comprise more nearly + * equal numbers of original runs). + * + * The actual cache-friendly implementation will use a pseudo-stack + * to avoid recursion, and will unroll processing of runs of length 2, + * but it is otherwise similar to the recursive implementation. + */ + +typedef struct { + IV offset; /* offset of 1st of 2 runs at this level */ + IV runs; /* how many runs must be combined into 1 */ +} off_runs; /* pseudo-stack element */ + + +static I32 +cmp_desc(pTHX_ gptr const a, gptr const b) +{ + return -PL_sort_RealCmp(aTHX_ a, b); +} + +STATIC void +S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp, U32 flags) +{ + IV i, run, offset; + I32 sense, level; + gptr *f1, *f2, *t, *b, *p; + int iwhich; + gptr *aux; + gptr *p1; + gptr small[SMALLSORT]; + gptr *which[3]; + off_runs stack[60], *stackp; + SVCOMPARE_t savecmp = NULL; + + if (nmemb <= 1) return; /* sorted trivially */ + + if ((flags & SORTf_DESC) != 0) { + savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ + PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */ + cmp = cmp_desc; + } + + if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */ + else { Newx(aux,nmemb,gptr); } /* allocate auxiliary array */ + level = 0; + stackp = stack; + stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp); + stackp->offset = offset = 0; + which[0] = which[2] = base; + which[1] = aux; + for (;;) { + /* On levels where both runs have be constructed (stackp->runs == 0), + * merge them, and note the offset of their end, in case the offset + * is needed at the next level up. Hop up a level, and, + * as long as stackp->runs is 0, keep merging. + */ + IV runs = stackp->runs; + if (runs == 0) { + gptr *list1, *list2; + iwhich = level & 1; + list1 = which[iwhich]; /* area where runs are now */ + list2 = which[++iwhich]; /* area for merged runs */ + do { + gptr *l1, *l2, *tp2; + offset = stackp->offset; + f1 = p1 = list1 + offset; /* start of first run */ + p = tp2 = list2 + offset; /* where merged run will go */ + t = NEXT(p); /* where first run ends */ + f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */ + t = NEXT(t); /* where second runs ends */ + l2 = POTHER(t, list2, list1); /* ... on the other side */ + offset = PNELEM(list2, t); + while (f1 < l1 && f2 < l2) { + /* If head 1 is larger than head 2, find ALL the elements + ** in list 2 strictly less than head1, write them all, + ** then head 1. Then compare the new heads, and repeat, + ** until one or both lists are exhausted. + ** + ** In all comparisons (after establishing + ** which head to merge) the item to merge + ** (at pointer q) is the first operand of + ** the comparison. When we want to know + ** if "q is strictly less than the other", + ** we can't just do + ** cmp(q, other) < 0 + ** because stability demands that we treat equality + ** as high when q comes from l2, and as low when + ** q was from l1. So we ask the question by doing + ** cmp(q, other) <= sense + ** and make sense == 0 when equality should look low, + ** and -1 when equality should look high. + */ + + gptr *q; + if (cmp(aTHX_ *f1, *f2) <= 0) { + q = f2; b = f1; t = l1; + sense = -1; + } else { + q = f1; b = f2; t = l2; + sense = 0; + } + + + /* ramp up + ** + ** Leave t at something strictly + ** greater than q (or at the end of the list), + ** and b at something strictly less than q. + */ + for (i = 1, run = 0 ;;) { + if ((p = PINDEX(b, i)) >= t) { + /* off the end */ + if (((p = PINDEX(t, -1)) > b) && + (cmp(aTHX_ *q, *p) <= sense)) + t = p; + else b = p; + break; + } else if (cmp(aTHX_ *q, *p) <= sense) { + t = p; + break; + } else b = p; + if (++run >= RTHRESH) i += i; + } + + + /* q is known to follow b and must be inserted before t. + ** Increment b, so the range of possibilities is [b,t). + ** Round binary split down, to favor early appearance. + ** Adjust b and t until q belongs just before t. + */ + + b++; + while (b < t) { + p = PINDEX(b, (PNELEM(b, t) - 1) / 2); + if (cmp(aTHX_ *q, *p) <= sense) { + t = p; + } else b = p + 1; + } + + + /* Copy all the strictly low elements */ + + if (q == f1) { + FROMTOUPTO(f2, tp2, t); + *tp2++ = *f1++; + } else { + FROMTOUPTO(f1, tp2, t); + *tp2++ = *f2++; + } + } + + + /* Run out remaining list */ + if (f1 == l1) { + if (f2 < l2) FROMTOUPTO(f2, tp2, l2); + } else FROMTOUPTO(f1, tp2, l1); + p1 = NEXT(p1) = POTHER(tp2, list2, list1); + + if (--level == 0) goto done; + --stackp; + t = list1; list1 = list2; list2 = t; /* swap lists */ + } while ((runs = stackp->runs) == 0); + } + + + stackp->runs = 0; /* current run will finish level */ + /* While there are more than 2 runs remaining, + * turn them into exactly 2 runs (at the "other" level), + * each made up of approximately half the runs. + * Stack the second half for later processing, + * and set about producing the first half now. + */ + while (runs > 2) { + ++level; + ++stackp; + stackp->offset = offset; + runs -= stackp->runs = runs / 2; + } + /* We must construct a single run from 1 or 2 runs. + * All the original runs are in which[0] == base. + * The run we construct must end up in which[level&1]. + */ + iwhich = level & 1; + if (runs == 1) { + /* Constructing a single run from a single run. + * If it's where it belongs already, there's nothing to do. + * Otherwise, copy it to where it belongs. + * A run of 1 is either a singleton at level 0, + * or the second half of a split 3. In neither event + * is it necessary to set offset. It will be set by the merge + * that immediately follows. + */ + if (iwhich) { /* Belongs in aux, currently in base */ + f1 = b = PINDEX(base, offset); /* where list starts */ + f2 = PINDEX(aux, offset); /* where list goes */ + t = NEXT(f2); /* where list will end */ + offset = PNELEM(aux, t); /* offset thereof */ + t = PINDEX(base, offset); /* where it currently ends */ + FROMTOUPTO(f1, f2, t); /* copy */ + NEXT(b) = t; /* set up parallel pointer */ + } else if (level == 0) goto done; /* single run at level 0 */ + } else { + /* Constructing a single run from two runs. + * The merge code at the top will do that. + * We need only make sure the two runs are in the "other" array, + * so they'll end up in the correct array after the merge. + */ + ++level; + ++stackp; + stackp->offset = offset; + stackp->runs = 0; /* take care of both runs, trigger merge */ + if (!iwhich) { /* Merged runs belong in aux, copy 1st */ + f1 = b = PINDEX(base, offset); /* where first run starts */ + f2 = PINDEX(aux, offset); /* where it will be copied */ + t = NEXT(f2); /* where first run will end */ + offset = PNELEM(aux, t); /* offset thereof */ + p = PINDEX(base, offset); /* end of first run */ + t = NEXT(t); /* where second run will end */ + t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */ + FROMTOUPTO(f1, f2, t); /* copy both runs */ + NEXT(b) = p; /* paralleled pointer for 1st */ + NEXT(p) = t; /* ... and for second */ + } + } + } + done: + if (aux != small) Safefree(aux); /* free iff allocated */ + if (flags) { + PL_sort_RealCmp = savecmp; /* Restore current comparison routine, if any */ + } + return; +} + +/* + * The quicksort implementation was derived from source code contributed + * by Tom Horsley. + * + * NOTE: this code was derived from Tom Horsley's qsort replacement + * and should not be confused with the original code. + */ + +/* Copyright (C) Tom Horsley, 1997. All rights reserved. + + Permission granted to distribute under the same terms as perl which are + (briefly): + + This program is free software; you can redistribute it and/or modify + it under the terms of either: + + a) the GNU General Public License as published by the Free + Software Foundation; either version 1, or (at your option) any + later version, or + + b) the "Artistic License" which comes with this Kit. + + Details on the perl license can be found in the perl source code which + may be located via the www.perl.com web page. + + This is the most wonderfulest possible qsort I can come up with (and + still be mostly portable) My (limited) tests indicate it consistently + does about 20% fewer calls to compare than does the qsort in the Visual + C++ library, other vendors may vary. + + Some of the ideas in here can be found in "Algorithms" by Sedgewick, + others I invented myself (or more likely re-invented since they seemed + pretty obvious once I watched the algorithm operate for a while). + + Most of this code was written while watching the Marlins sweep the Giants + in the 1997 National League Playoffs - no Braves fans allowed to use this + code (just kidding :-). + + I realize that if I wanted to be true to the perl tradition, the only + comment in this file would be something like: + + ...they shuffled back towards the rear of the line. 'No, not at the + rear!' the slave-driver shouted. 'Three files up. And stay there... + + However, I really needed to violate that tradition just so I could keep + track of what happens myself, not to mention some poor fool trying to + understand this years from now :-). +*/ + +/* ********************************************************** Configuration */ + +#ifndef QSORT_ORDER_GUESS +#define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */ +#endif + +/* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for + future processing - a good max upper bound is log base 2 of memory size + (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can + safely be smaller than that since the program is taking up some space and + most operating systems only let you grab some subset of contiguous + memory (not to mention that you are normally sorting data larger than + 1 byte element size :-). +*/ +#ifndef QSORT_MAX_STACK +#define QSORT_MAX_STACK 32 +#endif + +/* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort. + Anything bigger and we use qsort. If you make this too small, the qsort + will probably break (or become less efficient), because it doesn't expect + the middle element of a partition to be the same as the right or left - + you have been warned). +*/ +#ifndef QSORT_BREAK_EVEN +#define QSORT_BREAK_EVEN 6 +#endif + +/* QSORT_PLAY_SAFE is the size of the largest partition we're willing + to go quadratic on. We innoculate larger partitions against + quadratic behavior by shuffling them before sorting. This is not + an absolute guarantee of non-quadratic behavior, but it would take + staggeringly bad luck to pick extreme elements as the pivot + from randomized data. +*/ +#ifndef QSORT_PLAY_SAFE +#define QSORT_PLAY_SAFE 255 +#endif + +/* ************************************************************* Data Types */ + +/* hold left and right index values of a partition waiting to be sorted (the + partition includes both left and right - right is NOT one past the end or + anything like that). +*/ +struct partition_stack_entry { + int left; + int right; +#ifdef QSORT_ORDER_GUESS + int qsort_break_even; +#endif +}; + +/* ******************************************************* Shorthand Macros */ + +/* Note that these macros will be used from inside the qsort function where + we happen to know that the variable 'elt_size' contains the size of an + array element and the variable 'temp' points to enough space to hold a + temp element and the variable 'array' points to the array being sorted + and 'compare' is the pointer to the compare routine. + + Also note that there are very many highly architecture specific ways + these might be sped up, but this is simply the most generally portable + code I could think of. +*/ + +/* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2 +*/ +#define qsort_cmp(elt1, elt2) \ + ((*compare)(aTHX_ array[elt1], array[elt2])) + +#ifdef QSORT_ORDER_GUESS +#define QSORT_NOTICE_SWAP swapped++; +#else +#define QSORT_NOTICE_SWAP +#endif + +/* swaps contents of array elements elt1, elt2. +*/ +#define qsort_swap(elt1, elt2) \ + STMT_START { \ + QSORT_NOTICE_SWAP \ + temp = array[elt1]; \ + array[elt1] = array[elt2]; \ + array[elt2] = temp; \ + } STMT_END + +/* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets + elt3 and elt3 gets elt1. +*/ +#define qsort_rotate(elt1, elt2, elt3) \ + STMT_START { \ + QSORT_NOTICE_SWAP \ + temp = array[elt1]; \ + array[elt1] = array[elt2]; \ + array[elt2] = array[elt3]; \ + array[elt3] = temp; \ + } STMT_END + +/* ************************************************************ Debug stuff */ + +#ifdef QSORT_DEBUG + +static void +break_here() +{ + return; /* good place to set a breakpoint */ +} + +#define qsort_assert(t) (void)( (t) || (break_here(), 0) ) + +static void +doqsort_all_asserts( + void * array, + size_t num_elts, + size_t elt_size, + int (*compare)(const void * elt1, const void * elt2), + int pc_left, int pc_right, int u_left, int u_right) +{ + int i; + + qsort_assert(pc_left <= pc_right); + qsort_assert(u_right < pc_left); + qsort_assert(pc_right < u_left); + for (i = u_right + 1; i < pc_left; ++i) { + qsort_assert(qsort_cmp(i, pc_left) < 0); + } + for (i = pc_left; i < pc_right; ++i) { + qsort_assert(qsort_cmp(i, pc_right) == 0); + } + for (i = pc_right + 1; i < u_left; ++i) { + qsort_assert(qsort_cmp(pc_right, i) < 0); + } +} + +#define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \ + doqsort_all_asserts(array, num_elts, elt_size, compare, \ + PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) + +#else + +#define qsort_assert(t) ((void)0) + +#define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0) + +#endif + +/* ****************************************************************** qsort */ + +STATIC void /* the standard unstable (u) quicksort (qsort) */ +S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare) +{ + SV * temp; + struct partition_stack_entry partition_stack[QSORT_MAX_STACK]; + int next_stack_entry = 0; + int part_left; + int part_right; +#ifdef QSORT_ORDER_GUESS + int qsort_break_even; + int swapped; +#endif + + PERL_ARGS_ASSERT_QSORTSVU; + + /* Make sure we actually have work to do. + */ + if (num_elts <= 1) { + return; + } + + /* Inoculate large partitions against quadratic behavior */ + if (num_elts > QSORT_PLAY_SAFE) { + size_t n; + SV ** const q = array; + for (n = num_elts; n > 1; ) { + const size_t j = (size_t)(n-- * Drand01()); + temp = q[j]; + q[j] = q[n]; + q[n] = temp; + } + } + + /* Setup the initial partition definition and fall into the sorting loop + */ + part_left = 0; + part_right = (int)(num_elts - 1); +#ifdef QSORT_ORDER_GUESS + qsort_break_even = QSORT_BREAK_EVEN; +#else +#define qsort_break_even QSORT_BREAK_EVEN +#endif + for ( ; ; ) { + if ((part_right - part_left) >= qsort_break_even) { + /* OK, this is gonna get hairy, so lets try to document all the + concepts and abbreviations and variables and what they keep + track of: + + pc: pivot chunk - the set of array elements we accumulate in the + middle of the partition, all equal in value to the original + pivot element selected. The pc is defined by: + + pc_left - the leftmost array index of the pc + pc_right - the rightmost array index of the pc + + we start with pc_left == pc_right and only one element + in the pivot chunk (but it can grow during the scan). + + u: uncompared elements - the set of elements in the partition + we have not yet compared to the pivot value. There are two + uncompared sets during the scan - one to the left of the pc + and one to the right. + + u_right - the rightmost index of the left side's uncompared set + u_left - the leftmost index of the right side's uncompared set + + The leftmost index of the left sides's uncompared set + doesn't need its own variable because it is always defined + by the leftmost edge of the whole partition (part_left). The + same goes for the rightmost edge of the right partition + (part_right). + + We know there are no uncompared elements on the left once we + get u_right < part_left and no uncompared elements on the + right once u_left > part_right. When both these conditions + are met, we have completed the scan of the partition. + + Any elements which are between the pivot chunk and the + uncompared elements should be less than the pivot value on + the left side and greater than the pivot value on the right + side (in fact, the goal of the whole algorithm is to arrange + for that to be true and make the groups of less-than and + greater-then elements into new partitions to sort again). + + As you marvel at the complexity of the code and wonder why it + has to be so confusing. Consider some of the things this level + of confusion brings: + + Once I do a compare, I squeeze every ounce of juice out of it. I + never do compare calls I don't have to do, and I certainly never + do redundant calls. + + I also never swap any elements unless I can prove there is a + good reason. Many sort algorithms will swap a known value with + an uncompared value just to get things in the right place (or + avoid complexity :-), but that uncompared value, once it gets + compared, may then have to be swapped again. A lot of the + complexity of this code is due to the fact that it never swaps + anything except compared values, and it only swaps them when the + compare shows they are out of position. + */ + int pc_left, pc_right; + int u_right, u_left; + + int s; + + pc_left = ((part_left + part_right) / 2); + pc_right = pc_left; + u_right = pc_left - 1; + u_left = pc_right + 1; + + /* Qsort works best when the pivot value is also the median value + in the partition (unfortunately you can't find the median value + without first sorting :-), so to give the algorithm a helping + hand, we pick 3 elements and sort them and use the median value + of that tiny set as the pivot value. + + Some versions of qsort like to use the left middle and right as + the 3 elements to sort so they can insure the ends of the + partition will contain values which will stop the scan in the + compare loop, but when you have to call an arbitrarily complex + routine to do a compare, its really better to just keep track of + array index values to know when you hit the edge of the + partition and avoid the extra compare. An even better reason to + avoid using a compare call is the fact that you can drop off the + edge of the array if someone foolishly provides you with an + unstable compare function that doesn't always provide consistent + results. + + So, since it is simpler for us to compare the three adjacent + elements in the middle of the partition, those are the ones we + pick here (conveniently pointed at by u_right, pc_left, and + u_left). The values of the left, center, and right elements + are referred to as l c and r in the following comments. + */ + +#ifdef QSORT_ORDER_GUESS + swapped = 0; +#endif + s = qsort_cmp(u_right, pc_left); + if (s < 0) { + /* l < c */ + s = qsort_cmp(pc_left, u_left); + /* if l < c, c < r - already in order - nothing to do */ + if (s == 0) { + /* l < c, c == r - already in order, pc grows */ + ++pc_right; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else if (s > 0) { + /* l < c, c > r - need to know more */ + s = qsort_cmp(u_right, u_left); + if (s < 0) { + /* l < c, c > r, l < r - swap c & r to get ordered */ + qsort_swap(pc_left, u_left); + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else if (s == 0) { + /* l < c, c > r, l == r - swap c&r, grow pc */ + qsort_swap(pc_left, u_left); + --pc_left; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else { + /* l < c, c > r, l > r - make lcr into rlc to get ordered */ + qsort_rotate(pc_left, u_right, u_left); + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } + } + } else if (s == 0) { + /* l == c */ + s = qsort_cmp(pc_left, u_left); + if (s < 0) { + /* l == c, c < r - already in order, grow pc */ + --pc_left; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else if (s == 0) { + /* l == c, c == r - already in order, grow pc both ways */ + --pc_left; + ++pc_right; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else { + /* l == c, c > r - swap l & r, grow pc */ + qsort_swap(u_right, u_left); + ++pc_right; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } + } else { + /* l > c */ + s = qsort_cmp(pc_left, u_left); + if (s < 0) { + /* l > c, c < r - need to know more */ + s = qsort_cmp(u_right, u_left); + if (s < 0) { + /* l > c, c < r, l < r - swap l & c to get ordered */ + qsort_swap(u_right, pc_left); + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else if (s == 0) { + /* l > c, c < r, l == r - swap l & c, grow pc */ + qsort_swap(u_right, pc_left); + ++pc_right; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else { + /* l > c, c < r, l > r - rotate lcr into crl to order */ + qsort_rotate(u_right, pc_left, u_left); + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } + } else if (s == 0) { + /* l > c, c == r - swap ends, grow pc */ + qsort_swap(u_right, u_left); + --pc_left; + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } else { + /* l > c, c > r - swap ends to get in order */ + qsort_swap(u_right, u_left); + qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); + } + } + /* We now know the 3 middle elements have been compared and + arranged in the desired order, so we can shrink the uncompared + sets on both sides + */ + --u_right; + ++u_left; + qsort_all_asserts(pc_left, pc_right, u_left, u_right); + + /* The above massive nested if was the simple part :-). We now have + the middle 3 elements ordered and we need to scan through the + uncompared sets on either side, swapping elements that are on + the wrong side or simply shuffling equal elements around to get + all equal elements into the pivot chunk. + */ + + for ( ; ; ) { + int still_work_on_left; + int still_work_on_right; + + /* Scan the uncompared values on the left. If I find a value + equal to the pivot value, move it over so it is adjacent to + the pivot chunk and expand the pivot chunk. If I find a value + less than the pivot value, then just leave it - its already + on the correct side of the partition. If I find a greater + value, then stop the scan. + */ + while ((still_work_on_left = (u_right >= part_left))) { + s = qsort_cmp(u_right, pc_left); + if (s < 0) { + --u_right; + } else if (s == 0) { + --pc_left; + if (pc_left != u_right) { + qsort_swap(u_right, pc_left); + } + --u_right; + } else { + break; + } + qsort_assert(u_right < pc_left); + qsort_assert(pc_left <= pc_right); + qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0); + qsort_assert(qsort_cmp(pc_left, pc_right) == 0); + } + + /* Do a mirror image scan of uncompared values on the right + */ + while ((still_work_on_right = (u_left <= part_right))) { + s = qsort_cmp(pc_right, u_left); + if (s < 0) { + ++u_left; + } else if (s == 0) { + ++pc_right; + if (pc_right != u_left) { + qsort_swap(pc_right, u_left); + } + ++u_left; + } else { + break; + } + qsort_assert(u_left > pc_right); + qsort_assert(pc_left <= pc_right); + qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0); + qsort_assert(qsort_cmp(pc_left, pc_right) == 0); + } + + if (still_work_on_left) { + /* I know I have a value on the left side which needs to be + on the right side, but I need to know more to decide + exactly the best thing to do with it. + */ + if (still_work_on_right) { + /* I know I have values on both side which are out of + position. This is a big win because I kill two birds + with one swap (so to speak). I can advance the + uncompared pointers on both sides after swapping both + of them into the right place. + */ + qsort_swap(u_right, u_left); + --u_right; + ++u_left; + qsort_all_asserts(pc_left, pc_right, u_left, u_right); + } else { + /* I have an out of position value on the left, but the + right is fully scanned, so I "slide" the pivot chunk + and any less-than values left one to make room for the + greater value over on the right. If the out of position + value is immediately adjacent to the pivot chunk (there + are no less-than values), I can do that with a swap, + otherwise, I have to rotate one of the less than values + into the former position of the out of position value + and the right end of the pivot chunk into the left end + (got all that?). + */ + --pc_left; + if (pc_left == u_right) { + qsort_swap(u_right, pc_right); + qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); + } else { + qsort_rotate(u_right, pc_left, pc_right); + qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); + } + --pc_right; + --u_right; + } + } else if (still_work_on_right) { + /* Mirror image of complex case above: I have an out of + position value on the right, but the left is fully + scanned, so I need to shuffle things around to make room + for the right value on the left. + */ + ++pc_right; + if (pc_right == u_left) { + qsort_swap(u_left, pc_left); + qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); + } else { + qsort_rotate(pc_right, pc_left, u_left); + qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); + } + ++pc_left; + ++u_left; + } else { + /* No more scanning required on either side of partition, + break out of loop and figure out next set of partitions + */ + break; + } + } + + /* The elements in the pivot chunk are now in the right place. They + will never move or be compared again. All I have to do is decide + what to do with the stuff to the left and right of the pivot + chunk. + + Notes on the QSORT_ORDER_GUESS ifdef code: + + 1. If I just built these partitions without swapping any (or + very many) elements, there is a chance that the elements are + already ordered properly (being properly ordered will + certainly result in no swapping, but the converse can't be + proved :-). + + 2. A (properly written) insertion sort will run faster on + already ordered data than qsort will. + + 3. Perhaps there is some way to make a good guess about + switching to an insertion sort earlier than partition size 6 + (for instance - we could save the partition size on the stack + and increase the size each time we find we didn't swap, thus + switching to insertion sort earlier for partitions with a + history of not swapping). + + 4. Naturally, if I just switch right away, it will make + artificial benchmarks with pure ascending (or descending) + data look really good, but is that a good reason in general? + Hard to say... + */ + +#ifdef QSORT_ORDER_GUESS + if (swapped < 3) { +#if QSORT_ORDER_GUESS == 1 + qsort_break_even = (part_right - part_left) + 1; +#endif +#if QSORT_ORDER_GUESS == 2 + qsort_break_even *= 2; +#endif +#if QSORT_ORDER_GUESS == 3 + const int prev_break = qsort_break_even; + qsort_break_even *= qsort_break_even; + if (qsort_break_even < prev_break) { + qsort_break_even = (part_right - part_left) + 1; + } +#endif + } else { + qsort_break_even = QSORT_BREAK_EVEN; + } +#endif + + if (part_left < pc_left) { + /* There are elements on the left which need more processing. + Check the right as well before deciding what to do. + */ + if (pc_right < part_right) { + /* We have two partitions to be sorted. Stack the biggest one + and process the smallest one on the next iteration. This + minimizes the stack height by insuring that any additional + stack entries must come from the smallest partition which + (because it is smallest) will have the fewest + opportunities to generate additional stack entries. + */ + if ((part_right - pc_right) > (pc_left - part_left)) { + /* stack the right partition, process the left */ + partition_stack[next_stack_entry].left = pc_right + 1; + partition_stack[next_stack_entry].right = part_right; +#ifdef QSORT_ORDER_GUESS + partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; +#endif + part_right = pc_left - 1; + } else { + /* stack the left partition, process the right */ + partition_stack[next_stack_entry].left = part_left; + partition_stack[next_stack_entry].right = pc_left - 1; +#ifdef QSORT_ORDER_GUESS + partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; +#endif + part_left = pc_right + 1; + } + qsort_assert(next_stack_entry < QSORT_MAX_STACK); + ++next_stack_entry; + } else { + /* The elements on the left are the only remaining elements + that need sorting, arrange for them to be processed as the + next partition. + */ + part_right = pc_left - 1; + } + } else if (pc_right < part_right) { + /* There is only one chunk on the right to be sorted, make it + the new partition and loop back around. + */ + part_left = pc_right + 1; + } else { + /* This whole partition wound up in the pivot chunk, so + we need to get a new partition off the stack. + */ + if (next_stack_entry == 0) { + /* the stack is empty - we are done */ + break; + } + --next_stack_entry; + part_left = partition_stack[next_stack_entry].left; + part_right = partition_stack[next_stack_entry].right; +#ifdef QSORT_ORDER_GUESS + qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; +#endif + } + } else { + /* This partition is too small to fool with qsort complexity, just + do an ordinary insertion sort to minimize overhead. + */ + int i; + /* Assume 1st element is in right place already, and start checking + at 2nd element to see where it should be inserted. + */ + for (i = part_left + 1; i <= part_right; ++i) { + int j; + /* Scan (backwards - just in case 'i' is already in right place) + through the elements already sorted to see if the ith element + belongs ahead of one of them. + */ + for (j = i - 1; j >= part_left; --j) { + if (qsort_cmp(i, j) >= 0) { + /* i belongs right after j + */ + break; + } + } + ++j; + if (j != i) { + /* Looks like we really need to move some things + */ + int k; + temp = array[i]; + for (k = i - 1; k >= j; --k) + array[k + 1] = array[k]; + array[j] = temp; + } + } + + /* That partition is now sorted, grab the next one, or get out + of the loop if there aren't any more. + */ + + if (next_stack_entry == 0) { + /* the stack is empty - we are done */ + break; + } + --next_stack_entry; + part_left = partition_stack[next_stack_entry].left; + part_right = partition_stack[next_stack_entry].right; +#ifdef QSORT_ORDER_GUESS + qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; +#endif + } + } + + /* Believe it or not, the array is sorted at this point! */ +} + +/* Stabilize what is, presumably, an otherwise unstable sort method. + * We do that by allocating (or having on hand) an array of pointers + * that is the same size as the original array of elements to be sorted. + * We initialize this parallel array with the addresses of the original + * array elements. This indirection can make you crazy. + * Some pictures can help. After initializing, we have + * + * indir list1 + * +----+ +----+ + * | | --------------> | | ------> first element to be sorted + * +----+ +----+ + * | | --------------> | | ------> second element to be sorted + * +----+ +----+ + * | | --------------> | | ------> third element to be sorted + * +----+ +----+ + * ... + * +----+ +----+ + * | | --------------> | | ------> n-1st element to be sorted + * +----+ +----+ + * | | --------------> | | ------> n-th element to be sorted + * +----+ +----+ + * + * During the sort phase, we leave the elements of list1 where they are, + * and sort the pointers in the indirect array in the same order determined + * by the original comparison routine on the elements pointed to. + * Because we don't move the elements of list1 around through + * this phase, we can break ties on elements that compare equal + * using their address in the list1 array, ensuring stability. + * This leaves us with something looking like + * + * indir list1 + * +----+ +----+ + * | | --+ +---> | | ------> first element to be sorted + * +----+ | | +----+ + * | | --|-------|---> | | ------> second element to be sorted + * +----+ | | +----+ + * | | --|-------+ +-> | | ------> third element to be sorted + * +----+ | | +----+ + * ... + * +----+ | | | | +----+ + * | | ---|-+ | +--> | | ------> n-1st element to be sorted + * +----+ | | +----+ + * | | ---+ +----> | | ------> n-th element to be sorted + * +----+ +----+ + * + * where the i-th element of the indirect array points to the element + * that should be i-th in the sorted array. After the sort phase, + * we have to put the elements of list1 into the places + * dictated by the indirect array. + */ + + +static I32 +cmpindir(pTHX_ gptr const a, gptr const b) +{ + gptr * const ap = (gptr *)a; + gptr * const bp = (gptr *)b; + const I32 sense = PL_sort_RealCmp(aTHX_ *ap, *bp); + + if (sense) + return sense; + return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0); +} + +static I32 +cmpindir_desc(pTHX_ gptr const a, gptr const b) +{ + gptr * const ap = (gptr *)a; + gptr * const bp = (gptr *)b; + const I32 sense = PL_sort_RealCmp(aTHX_ *ap, *bp); + + /* Reverse the default */ + if (sense) + return -sense; + /* But don't reverse the stability test. */ + return (ap > bp) ? 1 : ((ap < bp) ? -1 : 0); + +} + +STATIC void +S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp, U32 flags) +{ + if ((flags & SORTf_STABLE) != 0) { + gptr **pp, *q; + size_t n, j, i; + gptr *small[SMALLSORT], **indir, tmp; + SVCOMPARE_t savecmp; + if (nmemb <= 1) return; /* sorted trivially */ + + /* Small arrays can use the stack, big ones must be allocated */ + if (nmemb <= SMALLSORT) indir = small; + else { Newx(indir, nmemb, gptr *); } + + /* Copy pointers to original array elements into indirect array */ + for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++; + + savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ + PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */ + + /* sort, with indirection */ + if (flags & SORTf_DESC) + qsortsvu((gptr *)indir, nmemb, cmpindir_desc); + else + qsortsvu((gptr *)indir, nmemb, cmpindir); + + pp = indir; + q = list1; + for (n = nmemb; n--; ) { + /* Assert A: all elements of q with index > n are already + * in place. This is vacuously true at the start, and we + * put element n where it belongs below (if it wasn't + * already where it belonged). Assert B: we only move + * elements that aren't where they belong, + * so, by A, we never tamper with elements above n. + */ + j = pp[n] - q; /* This sets j so that q[j] is + * at pp[n]. *pp[j] belongs in + * q[j], by construction. + */ + if (n != j) { /* all's well if n == j */ + tmp = q[j]; /* save what's in q[j] */ + do { + q[j] = *pp[j]; /* put *pp[j] where it belongs */ + i = pp[j] - q; /* the index in q of the element + * just moved */ + pp[j] = q + j; /* this is ok now */ + } while ((j = i) != n); + /* There are only finitely many (nmemb) addresses + * in the pp array. + * So we must eventually revisit an index we saw before. + * Suppose the first revisited index is k != n. + * An index is visited because something else belongs there. + * If we visit k twice, then two different elements must + * belong in the same place, which cannot be. + * So j must get back to n, the loop terminates, + * and we put the saved element where it belongs. + */ + q[n] = tmp; /* put what belongs into + * the n-th element */ + } + } + + /* free iff allocated */ + if (indir != small) { Safefree(indir); } + /* restore prevailing comparison routine */ + PL_sort_RealCmp = savecmp; + } else if ((flags & SORTf_DESC) != 0) { + const SVCOMPARE_t savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ + PL_sort_RealCmp = cmp; /* Put comparison routine where cmp_desc can find it */ + cmp = cmp_desc; + qsortsvu(list1, nmemb, cmp); + /* restore prevailing comparison routine */ + PL_sort_RealCmp = savecmp; + } else { + qsortsvu(list1, nmemb, cmp); + } +} + +/* +=head1 Array Manipulation Functions + +=for apidoc sortsv + +Sort an array. Here is an example: + + sortsv(AvARRAY(av), av_top_index(av)+1, Perl_sv_cmp_locale); + +Currently this always uses mergesort. See sortsv_flags for a more +flexible routine. + +=cut +*/ + +void +Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) +{ + PERL_ARGS_ASSERT_SORTSV; + + sortsv_flags(array, nmemb, cmp, 0); +} + +/* +=for apidoc sortsv_flags + +Sort an array, with various options. + +=cut +*/ +void +Perl_sortsv_flags(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags) +{ + PERL_ARGS_ASSERT_SORTSV_FLAGS; + + if (flags & SORTf_QSORT) + S_qsortsv(aTHX_ array, nmemb, cmp, flags); + else + S_mergesortsv(aTHX_ array, nmemb, cmp, flags); +} + +#define SvNSIOK(sv) ((SvFLAGS(sv) & SVf_NOK) || ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK)) +#define SvSIOK(sv) ((SvFLAGS(sv) & (SVf_IOK|SVf_IVisUV)) == SVf_IOK) +#define SvNSIV(sv) ( SvNOK(sv) ? SvNVX(sv) : ( SvSIOK(sv) ? SvIVX(sv) : sv_2nv(sv) ) ) + +PP(pp_sort) +{ + dSP; dMARK; dORIGMARK; + SV **p1 = ORIGMARK+1, **p2; + SSize_t max, i; + AV* av = NULL; + GV *gv; + CV *cv = NULL; + I32 gimme = GIMME_V; + OP* const nextop = PL_op->op_next; + I32 overloading = 0; + bool hasargs = FALSE; + bool copytmps; + I32 is_xsub = 0; + I32 sorting_av = 0; + const U8 priv = PL_op->op_private; + const U8 flags = PL_op->op_flags; + U32 sort_flags = 0; + void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp, U32 flags) + = Perl_sortsv_flags; + I32 all_SIVs = 1; + + if ((priv & OPpSORT_DESCEND) != 0) + sort_flags |= SORTf_DESC; + if ((priv & OPpSORT_QSORT) != 0) + sort_flags |= SORTf_QSORT; + if ((priv & OPpSORT_STABLE) != 0) + sort_flags |= SORTf_STABLE; + + if (gimme != G_ARRAY) { + SP = MARK; + EXTEND(SP,1); + RETPUSHUNDEF; + } + + ENTER; + SAVEVPTR(PL_sortcop); + if (flags & OPf_STACKED) { + if (flags & OPf_SPECIAL) { + OP *nullop = OpSIBLING(cLISTOP->op_first); /* pass pushmark */ + assert(nullop->op_type == OP_NULL); + PL_sortcop = nullop->op_next; + } + else { + GV *autogv = NULL; + HV *stash; + cv = sv_2cv(*++MARK, &stash, &gv, GV_ADD); + check_cv: + if (cv && SvPOK(cv)) { + const char * const proto = SvPV_nolen_const(MUTABLE_SV(cv)); + if (proto && strEQ(proto, "$$")) { + hasargs = TRUE; + } + } + if (cv && CvISXSUB(cv) && CvXSUB(cv)) { + is_xsub = 1; + } + else if (!(cv && CvROOT(cv))) { + if (gv) { + goto autoload; + } + else if (!CvANON(cv) && (gv = CvGV(cv))) { + if (cv != GvCV(gv)) cv = GvCV(gv); + autoload: + if (!autogv && ( + autogv = gv_autoload_pvn( + GvSTASH(gv), GvNAME(gv), GvNAMELEN(gv), + GvNAMEUTF8(gv) ? SVf_UTF8 : 0 + ) + )) { + cv = GvCVu(autogv); + goto check_cv; + } + else { + SV *tmpstr = sv_newmortal(); + gv_efullname3(tmpstr, gv, NULL); + DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called", + SVfARG(tmpstr)); + } + } + else { + DIE(aTHX_ "Undefined subroutine in sort"); + } + } + + if (is_xsub) + PL_sortcop = (OP*)cv; + else + PL_sortcop = CvSTART(cv); + } + } + else { + PL_sortcop = NULL; + } + + /* optimiser converts "@a = sort @a" to "sort \@a"; + * in case of tied @a, pessimise: push (@a) onto stack, then assign + * result back to @a at the end of this function */ + if (priv & OPpSORT_INPLACE) { + assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV); + (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */ + av = MUTABLE_AV((*SP)); + max = AvFILL(av) + 1; + if (SvMAGICAL(av)) { + MEXTEND(SP, max); + for (i=0; i < max; i++) { + SV **svp = av_fetch(av, i, FALSE); + *SP++ = (svp) ? *svp : NULL; + } + SP--; + p1 = p2 = SP - (max-1); + } + else { + if (SvREADONLY(av)) + Perl_croak_no_modify(); + else + { + SvREADONLY_on(av); + save_pushptr((void *)av, SAVEt_READONLY_OFF); + } + p1 = p2 = AvARRAY(av); + sorting_av = 1; + } + } + else { + p2 = MARK+1; + max = SP - MARK; + } + + /* shuffle stack down, removing optional initial cv (p1!=p2), plus + * any nulls; also stringify or converting to integer or number as + * required any args */ + copytmps = !sorting_av && PL_sortcop; + for (i=max; i > 0 ; i--) { + if ((*p1 = *p2++)) { /* Weed out nulls. */ + if (copytmps && SvPADTMP(*p1)) { + *p1 = sv_mortalcopy(*p1); + } + SvTEMP_off(*p1); + if (!PL_sortcop) { + if (priv & OPpSORT_NUMERIC) { + if (priv & OPpSORT_INTEGER) { + if (!SvIOK(*p1)) + (void)sv_2iv_flags(*p1, SV_GMAGIC|SV_SKIP_OVERLOAD); + } + else { + if (!SvNSIOK(*p1)) + (void)sv_2nv_flags(*p1, SV_GMAGIC|SV_SKIP_OVERLOAD); + if (all_SIVs && !SvSIOK(*p1)) + all_SIVs = 0; + } + } + else { + if (!SvPOK(*p1)) + (void)sv_2pv_flags(*p1, 0, + SV_GMAGIC|SV_CONST_RETURN|SV_SKIP_OVERLOAD); + } + if (SvAMAGIC(*p1)) + overloading = 1; + } + p1++; + } + else + max--; + } + if (sorting_av) + AvFILLp(av) = max-1; + + if (max > 1) { + SV **start; + if (PL_sortcop) { + PERL_CONTEXT *cx; + SV** newsp; + const bool oldcatch = CATCH_GET; + + SAVETMPS; + SAVEOP(); + + CATCH_SET(TRUE); + PUSHSTACKi(PERLSI_SORT); + if (!hasargs && !is_xsub) { + SAVEGENERICSV(PL_firstgv); + SAVEGENERICSV(PL_secondgv); + PL_firstgv = MUTABLE_GV(SvREFCNT_inc( + gv_fetchpvs("a", GV_ADD|GV_NOTQUAL, SVt_PV) + )); + PL_secondgv = MUTABLE_GV(SvREFCNT_inc( + gv_fetchpvs("b", GV_ADD|GV_NOTQUAL, SVt_PV) + )); + SAVESPTR(GvSV(PL_firstgv)); + SAVESPTR(GvSV(PL_secondgv)); + } + + PUSHBLOCK(cx, CXt_NULL, PL_stack_base); + if (!(flags & OPf_SPECIAL)) { + cx->cx_type = CXt_SUB; + cx->blk_gimme = G_SCALAR; + /* If our comparison routine is already active (CvDEPTH is + * is not 0), then PUSHSUB does not increase the refcount, + * so we have to do it ourselves, because the LEAVESUB fur- + * ther down lowers it. */ + if (CvDEPTH(cv)) SvREFCNT_inc_simple_void_NN(cv); + PUSHSUB(cx); + if (!is_xsub) { + PADLIST * const padlist = CvPADLIST(cv); + + if (++CvDEPTH(cv) >= 2) { + PERL_STACK_OVERFLOW_CHECK(); + pad_push(padlist, CvDEPTH(cv)); + } + SAVECOMPPAD(); + PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv)); + + if (hasargs) { + /* This is mostly copied from pp_entersub */ + AV * const av = MUTABLE_AV(PAD_SVl(0)); + + cx->blk_sub.savearray = GvAV(PL_defgv); + GvAV(PL_defgv) = MUTABLE_AV(SvREFCNT_inc_simple(av)); + CX_CURPAD_SAVE(cx->blk_sub); + cx->blk_sub.argarray = av; + } + + } + } + cx->cx_type |= CXp_MULTICALL; + + start = p1 - max; + sortsvp(aTHX_ start, max, + (is_xsub ? S_sortcv_xsub : hasargs ? S_sortcv_stacked : S_sortcv), + sort_flags); + + if (!(flags & OPf_SPECIAL)) { + SV *sv; + /* Reset cx, in case the context stack has been + reallocated. */ + cx = &cxstack[cxstack_ix]; + POPSUB(cx, sv); + LEAVESUB(sv); + } + POPBLOCK(cx,PL_curpm); + PL_stack_sp = newsp; + POPSTACK; + CATCH_SET(oldcatch); + } + else { + MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */ + start = sorting_av ? AvARRAY(av) : ORIGMARK+1; + sortsvp(aTHX_ start, max, + (priv & OPpSORT_NUMERIC) + ? ( ( ( priv & OPpSORT_INTEGER) || all_SIVs) + ? ( overloading ? S_amagic_i_ncmp : S_sv_i_ncmp) + : ( overloading ? S_amagic_ncmp : S_sv_ncmp ) ) + : ( +#ifdef USE_LOCALE_COLLATE + IN_LC_RUNTIME(LC_COLLATE) + ? ( overloading + ? (SVCOMPARE_t)S_amagic_cmp_locale + : (SVCOMPARE_t)sv_cmp_locale_static) + : +#endif + ( overloading ? (SVCOMPARE_t)S_amagic_cmp : (SVCOMPARE_t)sv_cmp_static)), + sort_flags); + } + if ((priv & OPpSORT_REVERSE) != 0) { + SV **q = start+max-1; + while (start < q) { + SV * const tmp = *start; + *start++ = *q; + *q-- = tmp; + } + } + } + if (sorting_av) + SvREADONLY_off(av); + else if (av && !sorting_av) { + /* simulate pp_aassign of tied AV */ + SV** const base = MARK+1; + for (i=0; i < max; i++) { + base[i] = newSVsv(base[i]); + } + av_clear(av); + av_extend(av, max); + for (i=0; i < max; i++) { + SV * const sv = base[i]; + SV ** const didstore = av_store(av, i, sv); + if (SvSMAGICAL(sv)) + mg_set(sv); + if (!didstore) + sv_2mortal(sv); + } + } + LEAVE; + PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max); + return nextop; +} + +static I32 +S_sortcv(pTHX_ SV *const a, SV *const b) +{ + const I32 oldsaveix = PL_savestack_ix; + const I32 oldscopeix = PL_scopestack_ix; + I32 result; + SV *resultsv; + PMOP * const pm = PL_curpm; + OP * const sortop = PL_op; + COP * const cop = PL_curcop; + + PERL_ARGS_ASSERT_SORTCV; + + GvSV(PL_firstgv) = a; + GvSV(PL_secondgv) = b; + PL_stack_sp = PL_stack_base; + PL_op = PL_sortcop; + CALLRUNOPS(aTHX); + PL_op = sortop; + PL_curcop = cop; + if (PL_stack_sp != PL_stack_base + 1) { + assert(PL_stack_sp == PL_stack_base); + resultsv = &PL_sv_undef; + } + else resultsv = *PL_stack_sp; + if (SvNIOK_nog(resultsv)) result = SvIV(resultsv); + else { + ENTER; + SAVEVPTR(PL_curpad); + PL_curpad = 0; + result = SvIV(resultsv); + LEAVE; + } + while (PL_scopestack_ix > oldscopeix) { + LEAVE; + } + leave_scope(oldsaveix); + PL_curpm = pm; + return result; +} + +static I32 +S_sortcv_stacked(pTHX_ SV *const a, SV *const b) +{ + const I32 oldsaveix = PL_savestack_ix; + const I32 oldscopeix = PL_scopestack_ix; + I32 result; + AV * const av = GvAV(PL_defgv); + PMOP * const pm = PL_curpm; + OP * const sortop = PL_op; + COP * const cop = PL_curcop; + SV **pad; + + PERL_ARGS_ASSERT_SORTCV_STACKED; + + if (AvREAL(av)) { + av_clear(av); + AvREAL_off(av); + AvREIFY_on(av); + } + if (AvMAX(av) < 1) { + SV **ary = AvALLOC(av); + if (AvARRAY(av) != ary) { + AvMAX(av) += AvARRAY(av) - AvALLOC(av); + AvARRAY(av) = ary; + } + if (AvMAX(av) < 1) { + AvMAX(av) = 1; + Renew(ary,2,SV*); + AvARRAY(av) = ary; + AvALLOC(av) = ary; + } + } + AvFILLp(av) = 1; + + AvARRAY(av)[0] = a; + AvARRAY(av)[1] = b; + PL_stack_sp = PL_stack_base; + PL_op = PL_sortcop; + CALLRUNOPS(aTHX); + PL_op = sortop; + PL_curcop = cop; + pad = PL_curpad; PL_curpad = 0; + if (PL_stack_sp != PL_stack_base + 1) { + assert(PL_stack_sp == PL_stack_base); + result = SvIV(&PL_sv_undef); + } + else result = SvIV(*PL_stack_sp); + PL_curpad = pad; + while (PL_scopestack_ix > oldscopeix) { + LEAVE; + } + leave_scope(oldsaveix); + PL_curpm = pm; + return result; +} + +static I32 +S_sortcv_xsub(pTHX_ SV *const a, SV *const b) +{ + dSP; + const I32 oldsaveix = PL_savestack_ix; + const I32 oldscopeix = PL_scopestack_ix; + CV * const cv=MUTABLE_CV(PL_sortcop); + I32 result; + PMOP * const pm = PL_curpm; + + PERL_ARGS_ASSERT_SORTCV_XSUB; + + SP = PL_stack_base; + PUSHMARK(SP); + EXTEND(SP, 2); + *++SP = a; + *++SP = b; + PUTBACK; + (void)(*CvXSUB(cv))(aTHX_ cv); + if (PL_stack_sp != PL_stack_base + 1) + Perl_croak(aTHX_ "Sort subroutine didn't return single value"); + result = SvIV(*PL_stack_sp); + while (PL_scopestack_ix > oldscopeix) { + LEAVE; + } + leave_scope(oldsaveix); + PL_curpm = pm; + return result; +} + + +static I32 +S_sv_ncmp(pTHX_ SV *const a, SV *const b) +{ + const NV nv1 = SvNSIV(a); + const NV nv2 = SvNSIV(b); + + PERL_ARGS_ASSERT_SV_NCMP; + +#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan) + if (Perl_isnan(nv1) || Perl_isnan(nv2)) { +#else + if (nv1 != nv1 || nv2 != nv2) { +#endif + if (ckWARN(WARN_UNINITIALIZED)) report_uninit(NULL); + return 0; + } + return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0; +} + +static I32 +S_sv_i_ncmp(pTHX_ SV *const a, SV *const b) +{ + const IV iv1 = SvIV(a); + const IV iv2 = SvIV(b); + + PERL_ARGS_ASSERT_SV_I_NCMP; + + return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0; +} + +#define tryCALL_AMAGICbin(left,right,meth) \ + (SvAMAGIC(left)||SvAMAGIC(right)) \ + ? amagic_call(left, right, meth, 0) \ + : NULL; + +#define SORT_NORMAL_RETURN_VALUE(val) (((val) > 0) ? 1 : ((val) ? -1 : 0)) + +static I32 +S_amagic_ncmp(pTHX_ SV *const a, SV *const b) +{ + SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp_amg); + + PERL_ARGS_ASSERT_AMAGIC_NCMP; + + if (tmpsv) { + if (SvIOK(tmpsv)) { + const I32 i = SvIVX(tmpsv); + return SORT_NORMAL_RETURN_VALUE(i); + } + else { + const NV d = SvNV(tmpsv); + return SORT_NORMAL_RETURN_VALUE(d); + } + } + return S_sv_ncmp(aTHX_ a, b); +} + +static I32 +S_amagic_i_ncmp(pTHX_ SV *const a, SV *const b) +{ + SV * const tmpsv = tryCALL_AMAGICbin(a,b,ncmp_amg); + + PERL_ARGS_ASSERT_AMAGIC_I_NCMP; + + if (tmpsv) { + if (SvIOK(tmpsv)) { + const I32 i = SvIVX(tmpsv); + return SORT_NORMAL_RETURN_VALUE(i); + } + else { + const NV d = SvNV(tmpsv); + return SORT_NORMAL_RETURN_VALUE(d); + } + } + return S_sv_i_ncmp(aTHX_ a, b); +} + +static I32 +S_amagic_cmp(pTHX_ SV *const str1, SV *const str2) +{ + SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp_amg); + + PERL_ARGS_ASSERT_AMAGIC_CMP; + + if (tmpsv) { + if (SvIOK(tmpsv)) { + const I32 i = SvIVX(tmpsv); + return SORT_NORMAL_RETURN_VALUE(i); + } + else { + const NV d = SvNV(tmpsv); + return SORT_NORMAL_RETURN_VALUE(d); + } + } + return sv_cmp(str1, str2); +} + +#ifdef USE_LOCALE_COLLATE + +static I32 +S_amagic_cmp_locale(pTHX_ SV *const str1, SV *const str2) +{ + SV * const tmpsv = tryCALL_AMAGICbin(str1,str2,scmp_amg); + + PERL_ARGS_ASSERT_AMAGIC_CMP_LOCALE; + + if (tmpsv) { + if (SvIOK(tmpsv)) { + const I32 i = SvIVX(tmpsv); + return SORT_NORMAL_RETURN_VALUE(i); + } + else { + const NV d = SvNV(tmpsv); + return SORT_NORMAL_RETURN_VALUE(d); + } + } + return sv_cmp_locale(str1, str2); +} + +#endif + +/* + * ex: set ts=8 sts=4 sw=4 et: + */