| 1 | /* pp_sort.c |
| 2 | * |
| 3 | * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, |
| 4 | * 2000, 2001, 2002, 2003, by Larry Wall and others |
| 5 | * |
| 6 | * You may distribute under the terms of either the GNU General Public |
| 7 | * License or the Artistic License, as specified in the README file. |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | /* |
| 12 | * ...they shuffled back towards the rear of the line. 'No, not at the |
| 13 | * rear!' the slave-driver shouted. 'Three files up. And stay there... |
| 14 | */ |
| 15 | |
| 16 | #include "EXTERN.h" |
| 17 | #define PERL_IN_PP_SORT_C |
| 18 | #include "perl.h" |
| 19 | |
| 20 | #if defined(UNDER_CE) |
| 21 | /* looks like 'small' is reserved word for WINCE (or somesuch)*/ |
| 22 | #define small xsmall |
| 23 | #endif |
| 24 | |
| 25 | static I32 sortcv(pTHX_ SV *a, SV *b); |
| 26 | static I32 sortcv_stacked(pTHX_ SV *a, SV *b); |
| 27 | static I32 sortcv_xsub(pTHX_ SV *a, SV *b); |
| 28 | static I32 sv_ncmp(pTHX_ SV *a, SV *b); |
| 29 | static I32 sv_i_ncmp(pTHX_ SV *a, SV *b); |
| 30 | static I32 amagic_ncmp(pTHX_ SV *a, SV *b); |
| 31 | static I32 amagic_i_ncmp(pTHX_ SV *a, SV *b); |
| 32 | static I32 amagic_cmp(pTHX_ SV *a, SV *b); |
| 33 | static I32 amagic_cmp_locale(pTHX_ SV *a, SV *b); |
| 34 | |
| 35 | #define sv_cmp_static Perl_sv_cmp |
| 36 | #define sv_cmp_locale_static Perl_sv_cmp_locale |
| 37 | |
| 38 | #define SORTHINTS(hintsv) \ |
| 39 | (((hintsv) = GvSV(gv_fetchpv("sort::hints", GV_ADDMULTI, SVt_IV))), \ |
| 40 | (SvIOK(hintsv) ? ((I32)SvIV(hintsv)) : 0)) |
| 41 | |
| 42 | #ifndef SMALLSORT |
| 43 | #define SMALLSORT (200) |
| 44 | #endif |
| 45 | |
| 46 | /* |
| 47 | * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>. |
| 48 | * |
| 49 | * The original code was written in conjunction with BSD Computer Software |
| 50 | * Research Group at University of California, Berkeley. |
| 51 | * |
| 52 | * See also: "Optimistic Merge Sort" (SODA '92) |
| 53 | * |
| 54 | * The integration to Perl is by John P. Linderman <jpl@research.att.com>. |
| 55 | * |
| 56 | * The code can be distributed under the same terms as Perl itself. |
| 57 | * |
| 58 | */ |
| 59 | |
| 60 | |
| 61 | typedef char * aptr; /* pointer for arithmetic on sizes */ |
| 62 | typedef SV * gptr; /* pointers in our lists */ |
| 63 | |
| 64 | /* Binary merge internal sort, with a few special mods |
| 65 | ** for the special perl environment it now finds itself in. |
| 66 | ** |
| 67 | ** Things that were once options have been hotwired |
| 68 | ** to values suitable for this use. In particular, we'll always |
| 69 | ** initialize looking for natural runs, we'll always produce stable |
| 70 | ** output, and we'll always do Peter McIlroy's binary merge. |
| 71 | */ |
| 72 | |
| 73 | /* Pointer types for arithmetic and storage and convenience casts */ |
| 74 | |
| 75 | #define APTR(P) ((aptr)(P)) |
| 76 | #define GPTP(P) ((gptr *)(P)) |
| 77 | #define GPPP(P) ((gptr **)(P)) |
| 78 | |
| 79 | |
| 80 | /* byte offset from pointer P to (larger) pointer Q */ |
| 81 | #define BYTEOFF(P, Q) (APTR(Q) - APTR(P)) |
| 82 | |
| 83 | #define PSIZE sizeof(gptr) |
| 84 | |
| 85 | /* If PSIZE is power of 2, make PSHIFT that power, if that helps */ |
| 86 | |
| 87 | #ifdef PSHIFT |
| 88 | #define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT)) |
| 89 | #define PNBYTE(N) ((N) << (PSHIFT)) |
| 90 | #define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N))) |
| 91 | #else |
| 92 | /* Leave optimization to compiler */ |
| 93 | #define PNELEM(P, Q) (GPTP(Q) - GPTP(P)) |
| 94 | #define PNBYTE(N) ((N) * (PSIZE)) |
| 95 | #define PINDEX(P, N) (GPTP(P) + (N)) |
| 96 | #endif |
| 97 | |
| 98 | /* Pointer into other corresponding to pointer into this */ |
| 99 | #define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P)) |
| 100 | |
| 101 | #define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim) |
| 102 | |
| 103 | |
| 104 | /* Runs are identified by a pointer in the auxilliary list. |
| 105 | ** The pointer is at the start of the list, |
| 106 | ** and it points to the start of the next list. |
| 107 | ** NEXT is used as an lvalue, too. |
| 108 | */ |
| 109 | |
| 110 | #define NEXT(P) (*GPPP(P)) |
| 111 | |
| 112 | |
| 113 | /* PTHRESH is the minimum number of pairs with the same sense to justify |
| 114 | ** checking for a run and extending it. Note that PTHRESH counts PAIRS, |
| 115 | ** not just elements, so PTHRESH == 8 means a run of 16. |
| 116 | */ |
| 117 | |
| 118 | #define PTHRESH (8) |
| 119 | |
| 120 | /* RTHRESH is the number of elements in a run that must compare low |
| 121 | ** to the low element from the opposing run before we justify |
| 122 | ** doing a binary rampup instead of single stepping. |
| 123 | ** In random input, N in a row low should only happen with |
| 124 | ** probability 2^(1-N), so we can risk that we are dealing |
| 125 | ** with orderly input without paying much when we aren't. |
| 126 | */ |
| 127 | |
| 128 | #define RTHRESH (6) |
| 129 | |
| 130 | |
| 131 | /* |
| 132 | ** Overview of algorithm and variables. |
| 133 | ** The array of elements at list1 will be organized into runs of length 2, |
| 134 | ** or runs of length >= 2 * PTHRESH. We only try to form long runs when |
| 135 | ** PTHRESH adjacent pairs compare in the same way, suggesting overall order. |
| 136 | ** |
| 137 | ** Unless otherwise specified, pair pointers address the first of two elements. |
| 138 | ** |
| 139 | ** b and b+1 are a pair that compare with sense ``sense''. |
| 140 | ** b is the ``bottom'' of adjacent pairs that might form a longer run. |
| 141 | ** |
| 142 | ** p2 parallels b in the list2 array, where runs are defined by |
| 143 | ** a pointer chain. |
| 144 | ** |
| 145 | ** t represents the ``top'' of the adjacent pairs that might extend |
| 146 | ** the run beginning at b. Usually, t addresses a pair |
| 147 | ** that compares with opposite sense from (b,b+1). |
| 148 | ** However, it may also address a singleton element at the end of list1, |
| 149 | ** or it may be equal to ``last'', the first element beyond list1. |
| 150 | ** |
| 151 | ** r addresses the Nth pair following b. If this would be beyond t, |
| 152 | ** we back it off to t. Only when r is less than t do we consider the |
| 153 | ** run long enough to consider checking. |
| 154 | ** |
| 155 | ** q addresses a pair such that the pairs at b through q already form a run. |
| 156 | ** Often, q will equal b, indicating we only are sure of the pair itself. |
| 157 | ** However, a search on the previous cycle may have revealed a longer run, |
| 158 | ** so q may be greater than b. |
| 159 | ** |
| 160 | ** p is used to work back from a candidate r, trying to reach q, |
| 161 | ** which would mean b through r would be a run. If we discover such a run, |
| 162 | ** we start q at r and try to push it further towards t. |
| 163 | ** If b through r is NOT a run, we detect the wrong order at (p-1,p). |
| 164 | ** In any event, after the check (if any), we have two main cases. |
| 165 | ** |
| 166 | ** 1) Short run. b <= q < p <= r <= t. |
| 167 | ** b through q is a run (perhaps trivial) |
| 168 | ** q through p are uninteresting pairs |
| 169 | ** p through r is a run |
| 170 | ** |
| 171 | ** 2) Long run. b < r <= q < t. |
| 172 | ** b through q is a run (of length >= 2 * PTHRESH) |
| 173 | ** |
| 174 | ** Note that degenerate cases are not only possible, but likely. |
| 175 | ** For example, if the pair following b compares with opposite sense, |
| 176 | ** then b == q < p == r == t. |
| 177 | */ |
| 178 | |
| 179 | |
| 180 | static IV |
| 181 | dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, SVCOMPARE_t cmp) |
| 182 | { |
| 183 | I32 sense; |
| 184 | register gptr *b, *p, *q, *t, *p2; |
| 185 | register gptr c, *last, *r; |
| 186 | gptr *savep; |
| 187 | IV runs = 0; |
| 188 | |
| 189 | b = list1; |
| 190 | last = PINDEX(b, nmemb); |
| 191 | sense = (cmp(aTHX_ *b, *(b+1)) > 0); |
| 192 | for (p2 = list2; b < last; ) { |
| 193 | /* We just started, or just reversed sense. |
| 194 | ** Set t at end of pairs with the prevailing sense. |
| 195 | */ |
| 196 | for (p = b+2, t = p; ++p < last; t = ++p) { |
| 197 | if ((cmp(aTHX_ *t, *p) > 0) != sense) break; |
| 198 | } |
| 199 | q = b; |
| 200 | /* Having laid out the playing field, look for long runs */ |
| 201 | do { |
| 202 | p = r = b + (2 * PTHRESH); |
| 203 | if (r >= t) p = r = t; /* too short to care about */ |
| 204 | else { |
| 205 | while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) && |
| 206 | ((p -= 2) > q)); |
| 207 | if (p <= q) { |
| 208 | /* b through r is a (long) run. |
| 209 | ** Extend it as far as possible. |
| 210 | */ |
| 211 | p = q = r; |
| 212 | while (((p += 2) < t) && |
| 213 | ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p; |
| 214 | r = p = q + 2; /* no simple pairs, no after-run */ |
| 215 | } |
| 216 | } |
| 217 | if (q > b) { /* run of greater than 2 at b */ |
| 218 | savep = p; |
| 219 | p = q += 2; |
| 220 | /* pick up singleton, if possible */ |
| 221 | if ((p == t) && |
| 222 | ((t + 1) == last) && |
| 223 | ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) |
| 224 | savep = r = p = q = last; |
| 225 | p2 = NEXT(p2) = p2 + (p - b); ++runs; |
| 226 | if (sense) while (b < --p) { |
| 227 | c = *b; |
| 228 | *b++ = *p; |
| 229 | *p = c; |
| 230 | } |
| 231 | p = savep; |
| 232 | } |
| 233 | while (q < p) { /* simple pairs */ |
| 234 | p2 = NEXT(p2) = p2 + 2; ++runs; |
| 235 | if (sense) { |
| 236 | c = *q++; |
| 237 | *(q-1) = *q; |
| 238 | *q++ = c; |
| 239 | } else q += 2; |
| 240 | } |
| 241 | if (((b = p) == t) && ((t+1) == last)) { |
| 242 | NEXT(p2) = p2 + 1; ++runs; |
| 243 | b++; |
| 244 | } |
| 245 | q = r; |
| 246 | } while (b < t); |
| 247 | sense = !sense; |
| 248 | } |
| 249 | return runs; |
| 250 | } |
| 251 | |
| 252 | |
| 253 | /* The original merge sort, in use since 5.7, was as fast as, or faster than, |
| 254 | * qsort on many platforms, but slower than qsort, conspicuously so, |
| 255 | * on others. The most likely explanation was platform-specific |
| 256 | * differences in cache sizes and relative speeds. |
| 257 | * |
| 258 | * The quicksort divide-and-conquer algorithm guarantees that, as the |
| 259 | * problem is subdivided into smaller and smaller parts, the parts |
| 260 | * fit into smaller (and faster) caches. So it doesn't matter how |
| 261 | * many levels of cache exist, quicksort will "find" them, and, |
| 262 | * as long as smaller is faster, take advanatge of them. |
| 263 | * |
| 264 | * By contrast, consider how the original mergesort algorithm worked. |
| 265 | * Suppose we have five runs (each typically of length 2 after dynprep). |
| 266 | * |
| 267 | * pass base aux |
| 268 | * 0 1 2 3 4 5 |
| 269 | * 1 12 34 5 |
| 270 | * 2 1234 5 |
| 271 | * 3 12345 |
| 272 | * 4 12345 |
| 273 | * |
| 274 | * Adjacent pairs are merged in "grand sweeps" through the input. |
| 275 | * This means, on pass 1, the records in runs 1 and 2 aren't revisited until |
| 276 | * runs 3 and 4 are merged and the runs from run 5 have been copied. |
| 277 | * The only cache that matters is one large enough to hold *all* the input. |
| 278 | * On some platforms, this may be many times slower than smaller caches. |
| 279 | * |
| 280 | * The following pseudo-code uses the same basic merge algorithm, |
| 281 | * but in a divide-and-conquer way. |
| 282 | * |
| 283 | * # merge $runs runs at offset $offset of list $list1 into $list2. |
| 284 | * # all unmerged runs ($runs == 1) originate in list $base. |
| 285 | * sub mgsort2 { |
| 286 | * my ($offset, $runs, $base, $list1, $list2) = @_; |
| 287 | * |
| 288 | * if ($runs == 1) { |
| 289 | * if ($list1 is $base) copy run to $list2 |
| 290 | * return offset of end of list (or copy) |
| 291 | * } else { |
| 292 | * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1) |
| 293 | * mgsort2($off2, $runs/2, $base, $list2, $list1) |
| 294 | * merge the adjacent runs at $offset of $list1 into $list2 |
| 295 | * return the offset of the end of the merged runs |
| 296 | * } |
| 297 | * } |
| 298 | * mgsort2(0, $runs, $base, $aux, $base); |
| 299 | * |
| 300 | * For our 5 runs, the tree of calls looks like |
| 301 | * |
| 302 | * 5 |
| 303 | * 3 2 |
| 304 | * 2 1 1 1 |
| 305 | * 1 1 |
| 306 | * |
| 307 | * 1 2 3 4 5 |
| 308 | * |
| 309 | * and the corresponding activity looks like |
| 310 | * |
| 311 | * copy runs 1 and 2 from base to aux |
| 312 | * merge runs 1 and 2 from aux to base |
| 313 | * (run 3 is where it belongs, no copy needed) |
| 314 | * merge runs 12 and 3 from base to aux |
| 315 | * (runs 4 and 5 are where they belong, no copy needed) |
| 316 | * merge runs 4 and 5 from base to aux |
| 317 | * merge runs 123 and 45 from aux to base |
| 318 | * |
| 319 | * Note that we merge runs 1 and 2 immediately after copying them, |
| 320 | * while they are still likely to be in fast cache. Similarly, |
| 321 | * run 3 is merged with run 12 while it still may be lingering in cache. |
| 322 | * This implementation should therefore enjoy much of the cache-friendly |
| 323 | * behavior that quicksort does. In addition, it does less copying |
| 324 | * than the original mergesort implementation (only runs 1 and 2 are copied) |
| 325 | * and the "balancing" of merges is better (merged runs comprise more nearly |
| 326 | * equal numbers of original runs). |
| 327 | * |
| 328 | * The actual cache-friendly implementation will use a pseudo-stack |
| 329 | * to avoid recursion, and will unroll processing of runs of length 2, |
| 330 | * but it is otherwise similar to the recursive implementation. |
| 331 | */ |
| 332 | |
| 333 | typedef struct { |
| 334 | IV offset; /* offset of 1st of 2 runs at this level */ |
| 335 | IV runs; /* how many runs must be combined into 1 */ |
| 336 | } off_runs; /* pseudo-stack element */ |
| 337 | |
| 338 | STATIC void |
| 339 | S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp) |
| 340 | { |
| 341 | IV i, run, runs, offset; |
| 342 | I32 sense, level; |
| 343 | int iwhich; |
| 344 | register gptr *f1, *f2, *t, *b, *p, *tp2, *l1, *l2, *q; |
| 345 | gptr *aux, *list1, *list2; |
| 346 | gptr *p1; |
| 347 | gptr small[SMALLSORT]; |
| 348 | gptr *which[3]; |
| 349 | off_runs stack[60], *stackp; |
| 350 | |
| 351 | if (nmemb <= 1) return; /* sorted trivially */ |
| 352 | if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */ |
| 353 | else { New(799,aux,nmemb,gptr); } /* allocate auxilliary array */ |
| 354 | level = 0; |
| 355 | stackp = stack; |
| 356 | stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp); |
| 357 | stackp->offset = offset = 0; |
| 358 | which[0] = which[2] = base; |
| 359 | which[1] = aux; |
| 360 | for (;;) { |
| 361 | /* On levels where both runs have be constructed (stackp->runs == 0), |
| 362 | * merge them, and note the offset of their end, in case the offset |
| 363 | * is needed at the next level up. Hop up a level, and, |
| 364 | * as long as stackp->runs is 0, keep merging. |
| 365 | */ |
| 366 | if ((runs = stackp->runs) == 0) { |
| 367 | iwhich = level & 1; |
| 368 | list1 = which[iwhich]; /* area where runs are now */ |
| 369 | list2 = which[++iwhich]; /* area for merged runs */ |
| 370 | do { |
| 371 | offset = stackp->offset; |
| 372 | f1 = p1 = list1 + offset; /* start of first run */ |
| 373 | p = tp2 = list2 + offset; /* where merged run will go */ |
| 374 | t = NEXT(p); /* where first run ends */ |
| 375 | f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */ |
| 376 | t = NEXT(t); /* where second runs ends */ |
| 377 | l2 = POTHER(t, list2, list1); /* ... on the other side */ |
| 378 | offset = PNELEM(list2, t); |
| 379 | while (f1 < l1 && f2 < l2) { |
| 380 | /* If head 1 is larger than head 2, find ALL the elements |
| 381 | ** in list 2 strictly less than head1, write them all, |
| 382 | ** then head 1. Then compare the new heads, and repeat, |
| 383 | ** until one or both lists are exhausted. |
| 384 | ** |
| 385 | ** In all comparisons (after establishing |
| 386 | ** which head to merge) the item to merge |
| 387 | ** (at pointer q) is the first operand of |
| 388 | ** the comparison. When we want to know |
| 389 | ** if ``q is strictly less than the other'', |
| 390 | ** we can't just do |
| 391 | ** cmp(q, other) < 0 |
| 392 | ** because stability demands that we treat equality |
| 393 | ** as high when q comes from l2, and as low when |
| 394 | ** q was from l1. So we ask the question by doing |
| 395 | ** cmp(q, other) <= sense |
| 396 | ** and make sense == 0 when equality should look low, |
| 397 | ** and -1 when equality should look high. |
| 398 | */ |
| 399 | |
| 400 | |
| 401 | if (cmp(aTHX_ *f1, *f2) <= 0) { |
| 402 | q = f2; b = f1; t = l1; |
| 403 | sense = -1; |
| 404 | } else { |
| 405 | q = f1; b = f2; t = l2; |
| 406 | sense = 0; |
| 407 | } |
| 408 | |
| 409 | |
| 410 | /* ramp up |
| 411 | ** |
| 412 | ** Leave t at something strictly |
| 413 | ** greater than q (or at the end of the list), |
| 414 | ** and b at something strictly less than q. |
| 415 | */ |
| 416 | for (i = 1, run = 0 ;;) { |
| 417 | if ((p = PINDEX(b, i)) >= t) { |
| 418 | /* off the end */ |
| 419 | if (((p = PINDEX(t, -1)) > b) && |
| 420 | (cmp(aTHX_ *q, *p) <= sense)) |
| 421 | t = p; |
| 422 | else b = p; |
| 423 | break; |
| 424 | } else if (cmp(aTHX_ *q, *p) <= sense) { |
| 425 | t = p; |
| 426 | break; |
| 427 | } else b = p; |
| 428 | if (++run >= RTHRESH) i += i; |
| 429 | } |
| 430 | |
| 431 | |
| 432 | /* q is known to follow b and must be inserted before t. |
| 433 | ** Increment b, so the range of possibilities is [b,t). |
| 434 | ** Round binary split down, to favor early appearance. |
| 435 | ** Adjust b and t until q belongs just before t. |
| 436 | */ |
| 437 | |
| 438 | b++; |
| 439 | while (b < t) { |
| 440 | p = PINDEX(b, (PNELEM(b, t) - 1) / 2); |
| 441 | if (cmp(aTHX_ *q, *p) <= sense) { |
| 442 | t = p; |
| 443 | } else b = p + 1; |
| 444 | } |
| 445 | |
| 446 | |
| 447 | /* Copy all the strictly low elements */ |
| 448 | |
| 449 | if (q == f1) { |
| 450 | FROMTOUPTO(f2, tp2, t); |
| 451 | *tp2++ = *f1++; |
| 452 | } else { |
| 453 | FROMTOUPTO(f1, tp2, t); |
| 454 | *tp2++ = *f2++; |
| 455 | } |
| 456 | } |
| 457 | |
| 458 | |
| 459 | /* Run out remaining list */ |
| 460 | if (f1 == l1) { |
| 461 | if (f2 < l2) FROMTOUPTO(f2, tp2, l2); |
| 462 | } else FROMTOUPTO(f1, tp2, l1); |
| 463 | p1 = NEXT(p1) = POTHER(tp2, list2, list1); |
| 464 | |
| 465 | if (--level == 0) goto done; |
| 466 | --stackp; |
| 467 | t = list1; list1 = list2; list2 = t; /* swap lists */ |
| 468 | } while ((runs = stackp->runs) == 0); |
| 469 | } |
| 470 | |
| 471 | |
| 472 | stackp->runs = 0; /* current run will finish level */ |
| 473 | /* While there are more than 2 runs remaining, |
| 474 | * turn them into exactly 2 runs (at the "other" level), |
| 475 | * each made up of approximately half the runs. |
| 476 | * Stack the second half for later processing, |
| 477 | * and set about producing the first half now. |
| 478 | */ |
| 479 | while (runs > 2) { |
| 480 | ++level; |
| 481 | ++stackp; |
| 482 | stackp->offset = offset; |
| 483 | runs -= stackp->runs = runs / 2; |
| 484 | } |
| 485 | /* We must construct a single run from 1 or 2 runs. |
| 486 | * All the original runs are in which[0] == base. |
| 487 | * The run we construct must end up in which[level&1]. |
| 488 | */ |
| 489 | iwhich = level & 1; |
| 490 | if (runs == 1) { |
| 491 | /* Constructing a single run from a single run. |
| 492 | * If it's where it belongs already, there's nothing to do. |
| 493 | * Otherwise, copy it to where it belongs. |
| 494 | * A run of 1 is either a singleton at level 0, |
| 495 | * or the second half of a split 3. In neither event |
| 496 | * is it necessary to set offset. It will be set by the merge |
| 497 | * that immediately follows. |
| 498 | */ |
| 499 | if (iwhich) { /* Belongs in aux, currently in base */ |
| 500 | f1 = b = PINDEX(base, offset); /* where list starts */ |
| 501 | f2 = PINDEX(aux, offset); /* where list goes */ |
| 502 | t = NEXT(f2); /* where list will end */ |
| 503 | offset = PNELEM(aux, t); /* offset thereof */ |
| 504 | t = PINDEX(base, offset); /* where it currently ends */ |
| 505 | FROMTOUPTO(f1, f2, t); /* copy */ |
| 506 | NEXT(b) = t; /* set up parallel pointer */ |
| 507 | } else if (level == 0) goto done; /* single run at level 0 */ |
| 508 | } else { |
| 509 | /* Constructing a single run from two runs. |
| 510 | * The merge code at the top will do that. |
| 511 | * We need only make sure the two runs are in the "other" array, |
| 512 | * so they'll end up in the correct array after the merge. |
| 513 | */ |
| 514 | ++level; |
| 515 | ++stackp; |
| 516 | stackp->offset = offset; |
| 517 | stackp->runs = 0; /* take care of both runs, trigger merge */ |
| 518 | if (!iwhich) { /* Merged runs belong in aux, copy 1st */ |
| 519 | f1 = b = PINDEX(base, offset); /* where first run starts */ |
| 520 | f2 = PINDEX(aux, offset); /* where it will be copied */ |
| 521 | t = NEXT(f2); /* where first run will end */ |
| 522 | offset = PNELEM(aux, t); /* offset thereof */ |
| 523 | p = PINDEX(base, offset); /* end of first run */ |
| 524 | t = NEXT(t); /* where second run will end */ |
| 525 | t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */ |
| 526 | FROMTOUPTO(f1, f2, t); /* copy both runs */ |
| 527 | NEXT(b) = p; /* paralled pointer for 1st */ |
| 528 | NEXT(p) = t; /* ... and for second */ |
| 529 | } |
| 530 | } |
| 531 | } |
| 532 | done: |
| 533 | if (aux != small) Safefree(aux); /* free iff allocated */ |
| 534 | return; |
| 535 | } |
| 536 | |
| 537 | /* |
| 538 | * The quicksort implementation was derived from source code contributed |
| 539 | * by Tom Horsley. |
| 540 | * |
| 541 | * NOTE: this code was derived from Tom Horsley's qsort replacement |
| 542 | * and should not be confused with the original code. |
| 543 | */ |
| 544 | |
| 545 | /* Copyright (C) Tom Horsley, 1997. All rights reserved. |
| 546 | |
| 547 | Permission granted to distribute under the same terms as perl which are |
| 548 | (briefly): |
| 549 | |
| 550 | This program is free software; you can redistribute it and/or modify |
| 551 | it under the terms of either: |
| 552 | |
| 553 | a) the GNU General Public License as published by the Free |
| 554 | Software Foundation; either version 1, or (at your option) any |
| 555 | later version, or |
| 556 | |
| 557 | b) the "Artistic License" which comes with this Kit. |
| 558 | |
| 559 | Details on the perl license can be found in the perl source code which |
| 560 | may be located via the www.perl.com web page. |
| 561 | |
| 562 | This is the most wonderfulest possible qsort I can come up with (and |
| 563 | still be mostly portable) My (limited) tests indicate it consistently |
| 564 | does about 20% fewer calls to compare than does the qsort in the Visual |
| 565 | C++ library, other vendors may vary. |
| 566 | |
| 567 | Some of the ideas in here can be found in "Algorithms" by Sedgewick, |
| 568 | others I invented myself (or more likely re-invented since they seemed |
| 569 | pretty obvious once I watched the algorithm operate for a while). |
| 570 | |
| 571 | Most of this code was written while watching the Marlins sweep the Giants |
| 572 | in the 1997 National League Playoffs - no Braves fans allowed to use this |
| 573 | code (just kidding :-). |
| 574 | |
| 575 | I realize that if I wanted to be true to the perl tradition, the only |
| 576 | comment in this file would be something like: |
| 577 | |
| 578 | ...they shuffled back towards the rear of the line. 'No, not at the |
| 579 | rear!' the slave-driver shouted. 'Three files up. And stay there... |
| 580 | |
| 581 | However, I really needed to violate that tradition just so I could keep |
| 582 | track of what happens myself, not to mention some poor fool trying to |
| 583 | understand this years from now :-). |
| 584 | */ |
| 585 | |
| 586 | /* ********************************************************** Configuration */ |
| 587 | |
| 588 | #ifndef QSORT_ORDER_GUESS |
| 589 | #define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */ |
| 590 | #endif |
| 591 | |
| 592 | /* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for |
| 593 | future processing - a good max upper bound is log base 2 of memory size |
| 594 | (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can |
| 595 | safely be smaller than that since the program is taking up some space and |
| 596 | most operating systems only let you grab some subset of contiguous |
| 597 | memory (not to mention that you are normally sorting data larger than |
| 598 | 1 byte element size :-). |
| 599 | */ |
| 600 | #ifndef QSORT_MAX_STACK |
| 601 | #define QSORT_MAX_STACK 32 |
| 602 | #endif |
| 603 | |
| 604 | /* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort. |
| 605 | Anything bigger and we use qsort. If you make this too small, the qsort |
| 606 | will probably break (or become less efficient), because it doesn't expect |
| 607 | the middle element of a partition to be the same as the right or left - |
| 608 | you have been warned). |
| 609 | */ |
| 610 | #ifndef QSORT_BREAK_EVEN |
| 611 | #define QSORT_BREAK_EVEN 6 |
| 612 | #endif |
| 613 | |
| 614 | /* QSORT_PLAY_SAFE is the size of the largest partition we're willing |
| 615 | to go quadratic on. We innoculate larger partitions against |
| 616 | quadratic behavior by shuffling them before sorting. This is not |
| 617 | an absolute guarantee of non-quadratic behavior, but it would take |
| 618 | staggeringly bad luck to pick extreme elements as the pivot |
| 619 | from randomized data. |
| 620 | */ |
| 621 | #ifndef QSORT_PLAY_SAFE |
| 622 | #define QSORT_PLAY_SAFE 255 |
| 623 | #endif |
| 624 | |
| 625 | /* ************************************************************* Data Types */ |
| 626 | |
| 627 | /* hold left and right index values of a partition waiting to be sorted (the |
| 628 | partition includes both left and right - right is NOT one past the end or |
| 629 | anything like that). |
| 630 | */ |
| 631 | struct partition_stack_entry { |
| 632 | int left; |
| 633 | int right; |
| 634 | #ifdef QSORT_ORDER_GUESS |
| 635 | int qsort_break_even; |
| 636 | #endif |
| 637 | }; |
| 638 | |
| 639 | /* ******************************************************* Shorthand Macros */ |
| 640 | |
| 641 | /* Note that these macros will be used from inside the qsort function where |
| 642 | we happen to know that the variable 'elt_size' contains the size of an |
| 643 | array element and the variable 'temp' points to enough space to hold a |
| 644 | temp element and the variable 'array' points to the array being sorted |
| 645 | and 'compare' is the pointer to the compare routine. |
| 646 | |
| 647 | Also note that there are very many highly architecture specific ways |
| 648 | these might be sped up, but this is simply the most generally portable |
| 649 | code I could think of. |
| 650 | */ |
| 651 | |
| 652 | /* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2 |
| 653 | */ |
| 654 | #define qsort_cmp(elt1, elt2) \ |
| 655 | ((*compare)(aTHX_ array[elt1], array[elt2])) |
| 656 | |
| 657 | #ifdef QSORT_ORDER_GUESS |
| 658 | #define QSORT_NOTICE_SWAP swapped++; |
| 659 | #else |
| 660 | #define QSORT_NOTICE_SWAP |
| 661 | #endif |
| 662 | |
| 663 | /* swaps contents of array elements elt1, elt2. |
| 664 | */ |
| 665 | #define qsort_swap(elt1, elt2) \ |
| 666 | STMT_START { \ |
| 667 | QSORT_NOTICE_SWAP \ |
| 668 | temp = array[elt1]; \ |
| 669 | array[elt1] = array[elt2]; \ |
| 670 | array[elt2] = temp; \ |
| 671 | } STMT_END |
| 672 | |
| 673 | /* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets |
| 674 | elt3 and elt3 gets elt1. |
| 675 | */ |
| 676 | #define qsort_rotate(elt1, elt2, elt3) \ |
| 677 | STMT_START { \ |
| 678 | QSORT_NOTICE_SWAP \ |
| 679 | temp = array[elt1]; \ |
| 680 | array[elt1] = array[elt2]; \ |
| 681 | array[elt2] = array[elt3]; \ |
| 682 | array[elt3] = temp; \ |
| 683 | } STMT_END |
| 684 | |
| 685 | /* ************************************************************ Debug stuff */ |
| 686 | |
| 687 | #ifdef QSORT_DEBUG |
| 688 | |
| 689 | static void |
| 690 | break_here() |
| 691 | { |
| 692 | return; /* good place to set a breakpoint */ |
| 693 | } |
| 694 | |
| 695 | #define qsort_assert(t) (void)( (t) || (break_here(), 0) ) |
| 696 | |
| 697 | static void |
| 698 | doqsort_all_asserts( |
| 699 | void * array, |
| 700 | size_t num_elts, |
| 701 | size_t elt_size, |
| 702 | int (*compare)(const void * elt1, const void * elt2), |
| 703 | int pc_left, int pc_right, int u_left, int u_right) |
| 704 | { |
| 705 | int i; |
| 706 | |
| 707 | qsort_assert(pc_left <= pc_right); |
| 708 | qsort_assert(u_right < pc_left); |
| 709 | qsort_assert(pc_right < u_left); |
| 710 | for (i = u_right + 1; i < pc_left; ++i) { |
| 711 | qsort_assert(qsort_cmp(i, pc_left) < 0); |
| 712 | } |
| 713 | for (i = pc_left; i < pc_right; ++i) { |
| 714 | qsort_assert(qsort_cmp(i, pc_right) == 0); |
| 715 | } |
| 716 | for (i = pc_right + 1; i < u_left; ++i) { |
| 717 | qsort_assert(qsort_cmp(pc_right, i) < 0); |
| 718 | } |
| 719 | } |
| 720 | |
| 721 | #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \ |
| 722 | doqsort_all_asserts(array, num_elts, elt_size, compare, \ |
| 723 | PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) |
| 724 | |
| 725 | #else |
| 726 | |
| 727 | #define qsort_assert(t) ((void)0) |
| 728 | |
| 729 | #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0) |
| 730 | |
| 731 | #endif |
| 732 | |
| 733 | /* ****************************************************************** qsort */ |
| 734 | |
| 735 | STATIC void /* the standard unstable (u) quicksort (qsort) */ |
| 736 | S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare) |
| 737 | { |
| 738 | register SV * temp; |
| 739 | |
| 740 | struct partition_stack_entry partition_stack[QSORT_MAX_STACK]; |
| 741 | int next_stack_entry = 0; |
| 742 | |
| 743 | int part_left; |
| 744 | int part_right; |
| 745 | #ifdef QSORT_ORDER_GUESS |
| 746 | int qsort_break_even; |
| 747 | int swapped; |
| 748 | #endif |
| 749 | |
| 750 | /* Make sure we actually have work to do. |
| 751 | */ |
| 752 | if (num_elts <= 1) { |
| 753 | return; |
| 754 | } |
| 755 | |
| 756 | /* Innoculate large partitions against quadratic behavior */ |
| 757 | if (num_elts > QSORT_PLAY_SAFE) { |
| 758 | register size_t n, j; |
| 759 | register SV **q; |
| 760 | for (n = num_elts, q = array; n > 1; ) { |
| 761 | j = (size_t)(n-- * Drand01()); |
| 762 | temp = q[j]; |
| 763 | q[j] = q[n]; |
| 764 | q[n] = temp; |
| 765 | } |
| 766 | } |
| 767 | |
| 768 | /* Setup the initial partition definition and fall into the sorting loop |
| 769 | */ |
| 770 | part_left = 0; |
| 771 | part_right = (int)(num_elts - 1); |
| 772 | #ifdef QSORT_ORDER_GUESS |
| 773 | qsort_break_even = QSORT_BREAK_EVEN; |
| 774 | #else |
| 775 | #define qsort_break_even QSORT_BREAK_EVEN |
| 776 | #endif |
| 777 | for ( ; ; ) { |
| 778 | if ((part_right - part_left) >= qsort_break_even) { |
| 779 | /* OK, this is gonna get hairy, so lets try to document all the |
| 780 | concepts and abbreviations and variables and what they keep |
| 781 | track of: |
| 782 | |
| 783 | pc: pivot chunk - the set of array elements we accumulate in the |
| 784 | middle of the partition, all equal in value to the original |
| 785 | pivot element selected. The pc is defined by: |
| 786 | |
| 787 | pc_left - the leftmost array index of the pc |
| 788 | pc_right - the rightmost array index of the pc |
| 789 | |
| 790 | we start with pc_left == pc_right and only one element |
| 791 | in the pivot chunk (but it can grow during the scan). |
| 792 | |
| 793 | u: uncompared elements - the set of elements in the partition |
| 794 | we have not yet compared to the pivot value. There are two |
| 795 | uncompared sets during the scan - one to the left of the pc |
| 796 | and one to the right. |
| 797 | |
| 798 | u_right - the rightmost index of the left side's uncompared set |
| 799 | u_left - the leftmost index of the right side's uncompared set |
| 800 | |
| 801 | The leftmost index of the left sides's uncompared set |
| 802 | doesn't need its own variable because it is always defined |
| 803 | by the leftmost edge of the whole partition (part_left). The |
| 804 | same goes for the rightmost edge of the right partition |
| 805 | (part_right). |
| 806 | |
| 807 | We know there are no uncompared elements on the left once we |
| 808 | get u_right < part_left and no uncompared elements on the |
| 809 | right once u_left > part_right. When both these conditions |
| 810 | are met, we have completed the scan of the partition. |
| 811 | |
| 812 | Any elements which are between the pivot chunk and the |
| 813 | uncompared elements should be less than the pivot value on |
| 814 | the left side and greater than the pivot value on the right |
| 815 | side (in fact, the goal of the whole algorithm is to arrange |
| 816 | for that to be true and make the groups of less-than and |
| 817 | greater-then elements into new partitions to sort again). |
| 818 | |
| 819 | As you marvel at the complexity of the code and wonder why it |
| 820 | has to be so confusing. Consider some of the things this level |
| 821 | of confusion brings: |
| 822 | |
| 823 | Once I do a compare, I squeeze every ounce of juice out of it. I |
| 824 | never do compare calls I don't have to do, and I certainly never |
| 825 | do redundant calls. |
| 826 | |
| 827 | I also never swap any elements unless I can prove there is a |
| 828 | good reason. Many sort algorithms will swap a known value with |
| 829 | an uncompared value just to get things in the right place (or |
| 830 | avoid complexity :-), but that uncompared value, once it gets |
| 831 | compared, may then have to be swapped again. A lot of the |
| 832 | complexity of this code is due to the fact that it never swaps |
| 833 | anything except compared values, and it only swaps them when the |
| 834 | compare shows they are out of position. |
| 835 | */ |
| 836 | int pc_left, pc_right; |
| 837 | int u_right, u_left; |
| 838 | |
| 839 | int s; |
| 840 | |
| 841 | pc_left = ((part_left + part_right) / 2); |
| 842 | pc_right = pc_left; |
| 843 | u_right = pc_left - 1; |
| 844 | u_left = pc_right + 1; |
| 845 | |
| 846 | /* Qsort works best when the pivot value is also the median value |
| 847 | in the partition (unfortunately you can't find the median value |
| 848 | without first sorting :-), so to give the algorithm a helping |
| 849 | hand, we pick 3 elements and sort them and use the median value |
| 850 | of that tiny set as the pivot value. |
| 851 | |
| 852 | Some versions of qsort like to use the left middle and right as |
| 853 | the 3 elements to sort so they can insure the ends of the |
| 854 | partition will contain values which will stop the scan in the |
| 855 | compare loop, but when you have to call an arbitrarily complex |
| 856 | routine to do a compare, its really better to just keep track of |
| 857 | array index values to know when you hit the edge of the |
| 858 | partition and avoid the extra compare. An even better reason to |
| 859 | avoid using a compare call is the fact that you can drop off the |
| 860 | edge of the array if someone foolishly provides you with an |
| 861 | unstable compare function that doesn't always provide consistent |
| 862 | results. |
| 863 | |
| 864 | So, since it is simpler for us to compare the three adjacent |
| 865 | elements in the middle of the partition, those are the ones we |
| 866 | pick here (conveniently pointed at by u_right, pc_left, and |
| 867 | u_left). The values of the left, center, and right elements |
| 868 | are refered to as l c and r in the following comments. |
| 869 | */ |
| 870 | |
| 871 | #ifdef QSORT_ORDER_GUESS |
| 872 | swapped = 0; |
| 873 | #endif |
| 874 | s = qsort_cmp(u_right, pc_left); |
| 875 | if (s < 0) { |
| 876 | /* l < c */ |
| 877 | s = qsort_cmp(pc_left, u_left); |
| 878 | /* if l < c, c < r - already in order - nothing to do */ |
| 879 | if (s == 0) { |
| 880 | /* l < c, c == r - already in order, pc grows */ |
| 881 | ++pc_right; |
| 882 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 883 | } else if (s > 0) { |
| 884 | /* l < c, c > r - need to know more */ |
| 885 | s = qsort_cmp(u_right, u_left); |
| 886 | if (s < 0) { |
| 887 | /* l < c, c > r, l < r - swap c & r to get ordered */ |
| 888 | qsort_swap(pc_left, u_left); |
| 889 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 890 | } else if (s == 0) { |
| 891 | /* l < c, c > r, l == r - swap c&r, grow pc */ |
| 892 | qsort_swap(pc_left, u_left); |
| 893 | --pc_left; |
| 894 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 895 | } else { |
| 896 | /* l < c, c > r, l > r - make lcr into rlc to get ordered */ |
| 897 | qsort_rotate(pc_left, u_right, u_left); |
| 898 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 899 | } |
| 900 | } |
| 901 | } else if (s == 0) { |
| 902 | /* l == c */ |
| 903 | s = qsort_cmp(pc_left, u_left); |
| 904 | if (s < 0) { |
| 905 | /* l == c, c < r - already in order, grow pc */ |
| 906 | --pc_left; |
| 907 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 908 | } else if (s == 0) { |
| 909 | /* l == c, c == r - already in order, grow pc both ways */ |
| 910 | --pc_left; |
| 911 | ++pc_right; |
| 912 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 913 | } else { |
| 914 | /* l == c, c > r - swap l & r, grow pc */ |
| 915 | qsort_swap(u_right, u_left); |
| 916 | ++pc_right; |
| 917 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 918 | } |
| 919 | } else { |
| 920 | /* l > c */ |
| 921 | s = qsort_cmp(pc_left, u_left); |
| 922 | if (s < 0) { |
| 923 | /* l > c, c < r - need to know more */ |
| 924 | s = qsort_cmp(u_right, u_left); |
| 925 | if (s < 0) { |
| 926 | /* l > c, c < r, l < r - swap l & c to get ordered */ |
| 927 | qsort_swap(u_right, pc_left); |
| 928 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 929 | } else if (s == 0) { |
| 930 | /* l > c, c < r, l == r - swap l & c, grow pc */ |
| 931 | qsort_swap(u_right, pc_left); |
| 932 | ++pc_right; |
| 933 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 934 | } else { |
| 935 | /* l > c, c < r, l > r - rotate lcr into crl to order */ |
| 936 | qsort_rotate(u_right, pc_left, u_left); |
| 937 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 938 | } |
| 939 | } else if (s == 0) { |
| 940 | /* l > c, c == r - swap ends, grow pc */ |
| 941 | qsort_swap(u_right, u_left); |
| 942 | --pc_left; |
| 943 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 944 | } else { |
| 945 | /* l > c, c > r - swap ends to get in order */ |
| 946 | qsort_swap(u_right, u_left); |
| 947 | qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); |
| 948 | } |
| 949 | } |
| 950 | /* We now know the 3 middle elements have been compared and |
| 951 | arranged in the desired order, so we can shrink the uncompared |
| 952 | sets on both sides |
| 953 | */ |
| 954 | --u_right; |
| 955 | ++u_left; |
| 956 | qsort_all_asserts(pc_left, pc_right, u_left, u_right); |
| 957 | |
| 958 | /* The above massive nested if was the simple part :-). We now have |
| 959 | the middle 3 elements ordered and we need to scan through the |
| 960 | uncompared sets on either side, swapping elements that are on |
| 961 | the wrong side or simply shuffling equal elements around to get |
| 962 | all equal elements into the pivot chunk. |
| 963 | */ |
| 964 | |
| 965 | for ( ; ; ) { |
| 966 | int still_work_on_left; |
| 967 | int still_work_on_right; |
| 968 | |
| 969 | /* Scan the uncompared values on the left. If I find a value |
| 970 | equal to the pivot value, move it over so it is adjacent to |
| 971 | the pivot chunk and expand the pivot chunk. If I find a value |
| 972 | less than the pivot value, then just leave it - its already |
| 973 | on the correct side of the partition. If I find a greater |
| 974 | value, then stop the scan. |
| 975 | */ |
| 976 | while ((still_work_on_left = (u_right >= part_left))) { |
| 977 | s = qsort_cmp(u_right, pc_left); |
| 978 | if (s < 0) { |
| 979 | --u_right; |
| 980 | } else if (s == 0) { |
| 981 | --pc_left; |
| 982 | if (pc_left != u_right) { |
| 983 | qsort_swap(u_right, pc_left); |
| 984 | } |
| 985 | --u_right; |
| 986 | } else { |
| 987 | break; |
| 988 | } |
| 989 | qsort_assert(u_right < pc_left); |
| 990 | qsort_assert(pc_left <= pc_right); |
| 991 | qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0); |
| 992 | qsort_assert(qsort_cmp(pc_left, pc_right) == 0); |
| 993 | } |
| 994 | |
| 995 | /* Do a mirror image scan of uncompared values on the right |
| 996 | */ |
| 997 | while ((still_work_on_right = (u_left <= part_right))) { |
| 998 | s = qsort_cmp(pc_right, u_left); |
| 999 | if (s < 0) { |
| 1000 | ++u_left; |
| 1001 | } else if (s == 0) { |
| 1002 | ++pc_right; |
| 1003 | if (pc_right != u_left) { |
| 1004 | qsort_swap(pc_right, u_left); |
| 1005 | } |
| 1006 | ++u_left; |
| 1007 | } else { |
| 1008 | break; |
| 1009 | } |
| 1010 | qsort_assert(u_left > pc_right); |
| 1011 | qsort_assert(pc_left <= pc_right); |
| 1012 | qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0); |
| 1013 | qsort_assert(qsort_cmp(pc_left, pc_right) == 0); |
| 1014 | } |
| 1015 | |
| 1016 | if (still_work_on_left) { |
| 1017 | /* I know I have a value on the left side which needs to be |
| 1018 | on the right side, but I need to know more to decide |
| 1019 | exactly the best thing to do with it. |
| 1020 | */ |
| 1021 | if (still_work_on_right) { |
| 1022 | /* I know I have values on both side which are out of |
| 1023 | position. This is a big win because I kill two birds |
| 1024 | with one swap (so to speak). I can advance the |
| 1025 | uncompared pointers on both sides after swapping both |
| 1026 | of them into the right place. |
| 1027 | */ |
| 1028 | qsort_swap(u_right, u_left); |
| 1029 | --u_right; |
| 1030 | ++u_left; |
| 1031 | qsort_all_asserts(pc_left, pc_right, u_left, u_right); |
| 1032 | } else { |
| 1033 | /* I have an out of position value on the left, but the |
| 1034 | right is fully scanned, so I "slide" the pivot chunk |
| 1035 | and any less-than values left one to make room for the |
| 1036 | greater value over on the right. If the out of position |
| 1037 | value is immediately adjacent to the pivot chunk (there |
| 1038 | are no less-than values), I can do that with a swap, |
| 1039 | otherwise, I have to rotate one of the less than values |
| 1040 | into the former position of the out of position value |
| 1041 | and the right end of the pivot chunk into the left end |
| 1042 | (got all that?). |
| 1043 | */ |
| 1044 | --pc_left; |
| 1045 | if (pc_left == u_right) { |
| 1046 | qsort_swap(u_right, pc_right); |
| 1047 | qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); |
| 1048 | } else { |
| 1049 | qsort_rotate(u_right, pc_left, pc_right); |
| 1050 | qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); |
| 1051 | } |
| 1052 | --pc_right; |
| 1053 | --u_right; |
| 1054 | } |
| 1055 | } else if (still_work_on_right) { |
| 1056 | /* Mirror image of complex case above: I have an out of |
| 1057 | position value on the right, but the left is fully |
| 1058 | scanned, so I need to shuffle things around to make room |
| 1059 | for the right value on the left. |
| 1060 | */ |
| 1061 | ++pc_right; |
| 1062 | if (pc_right == u_left) { |
| 1063 | qsort_swap(u_left, pc_left); |
| 1064 | qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); |
| 1065 | } else { |
| 1066 | qsort_rotate(pc_right, pc_left, u_left); |
| 1067 | qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); |
| 1068 | } |
| 1069 | ++pc_left; |
| 1070 | ++u_left; |
| 1071 | } else { |
| 1072 | /* No more scanning required on either side of partition, |
| 1073 | break out of loop and figure out next set of partitions |
| 1074 | */ |
| 1075 | break; |
| 1076 | } |
| 1077 | } |
| 1078 | |
| 1079 | /* The elements in the pivot chunk are now in the right place. They |
| 1080 | will never move or be compared again. All I have to do is decide |
| 1081 | what to do with the stuff to the left and right of the pivot |
| 1082 | chunk. |
| 1083 | |
| 1084 | Notes on the QSORT_ORDER_GUESS ifdef code: |
| 1085 | |
| 1086 | 1. If I just built these partitions without swapping any (or |
| 1087 | very many) elements, there is a chance that the elements are |
| 1088 | already ordered properly (being properly ordered will |
| 1089 | certainly result in no swapping, but the converse can't be |
| 1090 | proved :-). |
| 1091 | |
| 1092 | 2. A (properly written) insertion sort will run faster on |
| 1093 | already ordered data than qsort will. |
| 1094 | |
| 1095 | 3. Perhaps there is some way to make a good guess about |
| 1096 | switching to an insertion sort earlier than partition size 6 |
| 1097 | (for instance - we could save the partition size on the stack |
| 1098 | and increase the size each time we find we didn't swap, thus |
| 1099 | switching to insertion sort earlier for partitions with a |
| 1100 | history of not swapping). |
| 1101 | |
| 1102 | 4. Naturally, if I just switch right away, it will make |
| 1103 | artificial benchmarks with pure ascending (or descending) |
| 1104 | data look really good, but is that a good reason in general? |
| 1105 | Hard to say... |
| 1106 | */ |
| 1107 | |
| 1108 | #ifdef QSORT_ORDER_GUESS |
| 1109 | if (swapped < 3) { |
| 1110 | #if QSORT_ORDER_GUESS == 1 |
| 1111 | qsort_break_even = (part_right - part_left) + 1; |
| 1112 | #endif |
| 1113 | #if QSORT_ORDER_GUESS == 2 |
| 1114 | qsort_break_even *= 2; |
| 1115 | #endif |
| 1116 | #if QSORT_ORDER_GUESS == 3 |
| 1117 | int prev_break = qsort_break_even; |
| 1118 | qsort_break_even *= qsort_break_even; |
| 1119 | if (qsort_break_even < prev_break) { |
| 1120 | qsort_break_even = (part_right - part_left) + 1; |
| 1121 | } |
| 1122 | #endif |
| 1123 | } else { |
| 1124 | qsort_break_even = QSORT_BREAK_EVEN; |
| 1125 | } |
| 1126 | #endif |
| 1127 | |
| 1128 | if (part_left < pc_left) { |
| 1129 | /* There are elements on the left which need more processing. |
| 1130 | Check the right as well before deciding what to do. |
| 1131 | */ |
| 1132 | if (pc_right < part_right) { |
| 1133 | /* We have two partitions to be sorted. Stack the biggest one |
| 1134 | and process the smallest one on the next iteration. This |
| 1135 | minimizes the stack height by insuring that any additional |
| 1136 | stack entries must come from the smallest partition which |
| 1137 | (because it is smallest) will have the fewest |
| 1138 | opportunities to generate additional stack entries. |
| 1139 | */ |
| 1140 | if ((part_right - pc_right) > (pc_left - part_left)) { |
| 1141 | /* stack the right partition, process the left */ |
| 1142 | partition_stack[next_stack_entry].left = pc_right + 1; |
| 1143 | partition_stack[next_stack_entry].right = part_right; |
| 1144 | #ifdef QSORT_ORDER_GUESS |
| 1145 | partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; |
| 1146 | #endif |
| 1147 | part_right = pc_left - 1; |
| 1148 | } else { |
| 1149 | /* stack the left partition, process the right */ |
| 1150 | partition_stack[next_stack_entry].left = part_left; |
| 1151 | partition_stack[next_stack_entry].right = pc_left - 1; |
| 1152 | #ifdef QSORT_ORDER_GUESS |
| 1153 | partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; |
| 1154 | #endif |
| 1155 | part_left = pc_right + 1; |
| 1156 | } |
| 1157 | qsort_assert(next_stack_entry < QSORT_MAX_STACK); |
| 1158 | ++next_stack_entry; |
| 1159 | } else { |
| 1160 | /* The elements on the left are the only remaining elements |
| 1161 | that need sorting, arrange for them to be processed as the |
| 1162 | next partition. |
| 1163 | */ |
| 1164 | part_right = pc_left - 1; |
| 1165 | } |
| 1166 | } else if (pc_right < part_right) { |
| 1167 | /* There is only one chunk on the right to be sorted, make it |
| 1168 | the new partition and loop back around. |
| 1169 | */ |
| 1170 | part_left = pc_right + 1; |
| 1171 | } else { |
| 1172 | /* This whole partition wound up in the pivot chunk, so |
| 1173 | we need to get a new partition off the stack. |
| 1174 | */ |
| 1175 | if (next_stack_entry == 0) { |
| 1176 | /* the stack is empty - we are done */ |
| 1177 | break; |
| 1178 | } |
| 1179 | --next_stack_entry; |
| 1180 | part_left = partition_stack[next_stack_entry].left; |
| 1181 | part_right = partition_stack[next_stack_entry].right; |
| 1182 | #ifdef QSORT_ORDER_GUESS |
| 1183 | qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; |
| 1184 | #endif |
| 1185 | } |
| 1186 | } else { |
| 1187 | /* This partition is too small to fool with qsort complexity, just |
| 1188 | do an ordinary insertion sort to minimize overhead. |
| 1189 | */ |
| 1190 | int i; |
| 1191 | /* Assume 1st element is in right place already, and start checking |
| 1192 | at 2nd element to see where it should be inserted. |
| 1193 | */ |
| 1194 | for (i = part_left + 1; i <= part_right; ++i) { |
| 1195 | int j; |
| 1196 | /* Scan (backwards - just in case 'i' is already in right place) |
| 1197 | through the elements already sorted to see if the ith element |
| 1198 | belongs ahead of one of them. |
| 1199 | */ |
| 1200 | for (j = i - 1; j >= part_left; --j) { |
| 1201 | if (qsort_cmp(i, j) >= 0) { |
| 1202 | /* i belongs right after j |
| 1203 | */ |
| 1204 | break; |
| 1205 | } |
| 1206 | } |
| 1207 | ++j; |
| 1208 | if (j != i) { |
| 1209 | /* Looks like we really need to move some things |
| 1210 | */ |
| 1211 | int k; |
| 1212 | temp = array[i]; |
| 1213 | for (k = i - 1; k >= j; --k) |
| 1214 | array[k + 1] = array[k]; |
| 1215 | array[j] = temp; |
| 1216 | } |
| 1217 | } |
| 1218 | |
| 1219 | /* That partition is now sorted, grab the next one, or get out |
| 1220 | of the loop if there aren't any more. |
| 1221 | */ |
| 1222 | |
| 1223 | if (next_stack_entry == 0) { |
| 1224 | /* the stack is empty - we are done */ |
| 1225 | break; |
| 1226 | } |
| 1227 | --next_stack_entry; |
| 1228 | part_left = partition_stack[next_stack_entry].left; |
| 1229 | part_right = partition_stack[next_stack_entry].right; |
| 1230 | #ifdef QSORT_ORDER_GUESS |
| 1231 | qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; |
| 1232 | #endif |
| 1233 | } |
| 1234 | } |
| 1235 | |
| 1236 | /* Believe it or not, the array is sorted at this point! */ |
| 1237 | } |
| 1238 | |
| 1239 | /* Stabilize what is, presumably, an otherwise unstable sort method. |
| 1240 | * We do that by allocating (or having on hand) an array of pointers |
| 1241 | * that is the same size as the original array of elements to be sorted. |
| 1242 | * We initialize this parallel array with the addresses of the original |
| 1243 | * array elements. This indirection can make you crazy. |
| 1244 | * Some pictures can help. After initializing, we have |
| 1245 | * |
| 1246 | * indir list1 |
| 1247 | * +----+ +----+ |
| 1248 | * | | --------------> | | ------> first element to be sorted |
| 1249 | * +----+ +----+ |
| 1250 | * | | --------------> | | ------> second element to be sorted |
| 1251 | * +----+ +----+ |
| 1252 | * | | --------------> | | ------> third element to be sorted |
| 1253 | * +----+ +----+ |
| 1254 | * ... |
| 1255 | * +----+ +----+ |
| 1256 | * | | --------------> | | ------> n-1st element to be sorted |
| 1257 | * +----+ +----+ |
| 1258 | * | | --------------> | | ------> n-th element to be sorted |
| 1259 | * +----+ +----+ |
| 1260 | * |
| 1261 | * During the sort phase, we leave the elements of list1 where they are, |
| 1262 | * and sort the pointers in the indirect array in the same order determined |
| 1263 | * by the original comparison routine on the elements pointed to. |
| 1264 | * Because we don't move the elements of list1 around through |
| 1265 | * this phase, we can break ties on elements that compare equal |
| 1266 | * using their address in the list1 array, ensuring stabilty. |
| 1267 | * This leaves us with something looking like |
| 1268 | * |
| 1269 | * indir list1 |
| 1270 | * +----+ +----+ |
| 1271 | * | | --+ +---> | | ------> first element to be sorted |
| 1272 | * +----+ | | +----+ |
| 1273 | * | | --|-------|---> | | ------> second element to be sorted |
| 1274 | * +----+ | | +----+ |
| 1275 | * | | --|-------+ +-> | | ------> third element to be sorted |
| 1276 | * +----+ | | +----+ |
| 1277 | * ... |
| 1278 | * +----+ | | | | +----+ |
| 1279 | * | | ---|-+ | +--> | | ------> n-1st element to be sorted |
| 1280 | * +----+ | | +----+ |
| 1281 | * | | ---+ +----> | | ------> n-th element to be sorted |
| 1282 | * +----+ +----+ |
| 1283 | * |
| 1284 | * where the i-th element of the indirect array points to the element |
| 1285 | * that should be i-th in the sorted array. After the sort phase, |
| 1286 | * we have to put the elements of list1 into the places |
| 1287 | * dictated by the indirect array. |
| 1288 | */ |
| 1289 | |
| 1290 | |
| 1291 | static I32 |
| 1292 | cmpindir(pTHX_ gptr a, gptr b) |
| 1293 | { |
| 1294 | I32 sense; |
| 1295 | gptr *ap = (gptr *)a; |
| 1296 | gptr *bp = (gptr *)b; |
| 1297 | |
| 1298 | if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)) == 0) |
| 1299 | sense = (ap > bp) ? 1 : ((ap < bp) ? -1 : 0); |
| 1300 | return sense; |
| 1301 | } |
| 1302 | |
| 1303 | STATIC void |
| 1304 | S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp) |
| 1305 | { |
| 1306 | SV *hintsv; |
| 1307 | |
| 1308 | if (SORTHINTS(hintsv) & HINT_SORT_STABLE) { |
| 1309 | register gptr **pp, *q; |
| 1310 | register size_t n, j, i; |
| 1311 | gptr *small[SMALLSORT], **indir, tmp; |
| 1312 | SVCOMPARE_t savecmp; |
| 1313 | if (nmemb <= 1) return; /* sorted trivially */ |
| 1314 | |
| 1315 | /* Small arrays can use the stack, big ones must be allocated */ |
| 1316 | if (nmemb <= SMALLSORT) indir = small; |
| 1317 | else { New(1799, indir, nmemb, gptr *); } |
| 1318 | |
| 1319 | /* Copy pointers to original array elements into indirect array */ |
| 1320 | for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++; |
| 1321 | |
| 1322 | savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ |
| 1323 | PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */ |
| 1324 | |
| 1325 | /* sort, with indirection */ |
| 1326 | S_qsortsvu(aTHX_ (gptr *)indir, nmemb, cmpindir); |
| 1327 | |
| 1328 | pp = indir; |
| 1329 | q = list1; |
| 1330 | for (n = nmemb; n--; ) { |
| 1331 | /* Assert A: all elements of q with index > n are already |
| 1332 | * in place. This is vacuosly true at the start, and we |
| 1333 | * put element n where it belongs below (if it wasn't |
| 1334 | * already where it belonged). Assert B: we only move |
| 1335 | * elements that aren't where they belong, |
| 1336 | * so, by A, we never tamper with elements above n. |
| 1337 | */ |
| 1338 | j = pp[n] - q; /* This sets j so that q[j] is |
| 1339 | * at pp[n]. *pp[j] belongs in |
| 1340 | * q[j], by construction. |
| 1341 | */ |
| 1342 | if (n != j) { /* all's well if n == j */ |
| 1343 | tmp = q[j]; /* save what's in q[j] */ |
| 1344 | do { |
| 1345 | q[j] = *pp[j]; /* put *pp[j] where it belongs */ |
| 1346 | i = pp[j] - q; /* the index in q of the element |
| 1347 | * just moved */ |
| 1348 | pp[j] = q + j; /* this is ok now */ |
| 1349 | } while ((j = i) != n); |
| 1350 | /* There are only finitely many (nmemb) addresses |
| 1351 | * in the pp array. |
| 1352 | * So we must eventually revisit an index we saw before. |
| 1353 | * Suppose the first revisited index is k != n. |
| 1354 | * An index is visited because something else belongs there. |
| 1355 | * If we visit k twice, then two different elements must |
| 1356 | * belong in the same place, which cannot be. |
| 1357 | * So j must get back to n, the loop terminates, |
| 1358 | * and we put the saved element where it belongs. |
| 1359 | */ |
| 1360 | q[n] = tmp; /* put what belongs into |
| 1361 | * the n-th element */ |
| 1362 | } |
| 1363 | } |
| 1364 | |
| 1365 | /* free iff allocated */ |
| 1366 | if (indir != small) { Safefree(indir); } |
| 1367 | /* restore prevailing comparison routine */ |
| 1368 | PL_sort_RealCmp = savecmp; |
| 1369 | } else { |
| 1370 | S_qsortsvu(aTHX_ list1, nmemb, cmp); |
| 1371 | } |
| 1372 | } |
| 1373 | |
| 1374 | /* |
| 1375 | =head1 Array Manipulation Functions |
| 1376 | |
| 1377 | =for apidoc sortsv |
| 1378 | |
| 1379 | Sort an array. Here is an example: |
| 1380 | |
| 1381 | sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale); |
| 1382 | |
| 1383 | See lib/sort.pm for details about controlling the sorting algorithm. |
| 1384 | |
| 1385 | =cut |
| 1386 | */ |
| 1387 | |
| 1388 | void |
| 1389 | Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) |
| 1390 | { |
| 1391 | void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) = |
| 1392 | S_mergesortsv; |
| 1393 | SV *hintsv; |
| 1394 | I32 hints; |
| 1395 | |
| 1396 | /* Sun's Compiler (cc: WorkShop Compilers 4.2 30 Oct 1996 C 4.2) used |
| 1397 | to miscompile this function under optimization -O. If you get test |
| 1398 | errors related to picking the correct sort() function, try recompiling |
| 1399 | this file without optimiziation. -- A.D. 4/2002. |
| 1400 | */ |
| 1401 | hints = SORTHINTS(hintsv); |
| 1402 | if (hints & HINT_SORT_QUICKSORT) { |
| 1403 | sortsvp = S_qsortsv; |
| 1404 | } |
| 1405 | else { |
| 1406 | /* The default as of 5.8.0 is mergesort */ |
| 1407 | sortsvp = S_mergesortsv; |
| 1408 | } |
| 1409 | |
| 1410 | sortsvp(aTHX_ array, nmemb, cmp); |
| 1411 | } |
| 1412 | |
| 1413 | PP(pp_sort) |
| 1414 | { |
| 1415 | dSP; dMARK; dORIGMARK; |
| 1416 | register SV **p1 = ORIGMARK+1, **p2; |
| 1417 | register I32 max, i; |
| 1418 | AV* av = Nullav; |
| 1419 | HV *stash; |
| 1420 | GV *gv; |
| 1421 | CV *cv = 0; |
| 1422 | I32 gimme = GIMME; |
| 1423 | OP* nextop = PL_op->op_next; |
| 1424 | I32 overloading = 0; |
| 1425 | bool hasargs = FALSE; |
| 1426 | I32 is_xsub = 0; |
| 1427 | I32 sorting_av = 0; |
| 1428 | |
| 1429 | if (gimme != G_ARRAY) { |
| 1430 | SP = MARK; |
| 1431 | RETPUSHUNDEF; |
| 1432 | } |
| 1433 | |
| 1434 | ENTER; |
| 1435 | SAVEVPTR(PL_sortcop); |
| 1436 | if (PL_op->op_flags & OPf_STACKED) { |
| 1437 | if (PL_op->op_flags & OPf_SPECIAL) { |
| 1438 | OP *kid = cLISTOP->op_first->op_sibling; /* pass pushmark */ |
| 1439 | kid = kUNOP->op_first; /* pass rv2gv */ |
| 1440 | kid = kUNOP->op_first; /* pass leave */ |
| 1441 | PL_sortcop = kid->op_next; |
| 1442 | stash = CopSTASH(PL_curcop); |
| 1443 | } |
| 1444 | else { |
| 1445 | cv = sv_2cv(*++MARK, &stash, &gv, 0); |
| 1446 | if (cv && SvPOK(cv)) { |
| 1447 | STRLEN n_a; |
| 1448 | char *proto = SvPV((SV*)cv, n_a); |
| 1449 | if (proto && strEQ(proto, "$$")) { |
| 1450 | hasargs = TRUE; |
| 1451 | } |
| 1452 | } |
| 1453 | if (!(cv && CvROOT(cv))) { |
| 1454 | if (cv && CvXSUB(cv)) { |
| 1455 | is_xsub = 1; |
| 1456 | } |
| 1457 | else if (gv) { |
| 1458 | SV *tmpstr = sv_newmortal(); |
| 1459 | gv_efullname3(tmpstr, gv, Nullch); |
| 1460 | DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called", |
| 1461 | tmpstr); |
| 1462 | } |
| 1463 | else { |
| 1464 | DIE(aTHX_ "Undefined subroutine in sort"); |
| 1465 | } |
| 1466 | } |
| 1467 | |
| 1468 | if (is_xsub) |
| 1469 | PL_sortcop = (OP*)cv; |
| 1470 | else { |
| 1471 | PL_sortcop = CvSTART(cv); |
| 1472 | SAVEVPTR(CvROOT(cv)->op_ppaddr); |
| 1473 | CvROOT(cv)->op_ppaddr = PL_ppaddr[OP_NULL]; |
| 1474 | |
| 1475 | PAD_SET_CUR(CvPADLIST(cv), 1); |
| 1476 | } |
| 1477 | } |
| 1478 | } |
| 1479 | else { |
| 1480 | PL_sortcop = Nullop; |
| 1481 | stash = CopSTASH(PL_curcop); |
| 1482 | } |
| 1483 | |
| 1484 | /* optimiser converts "@a = sort @a" to "sort \@a"; |
| 1485 | * in case of tied @a, pessimise: push (@a) onto stack, then assign |
| 1486 | * result back to @a at the end of this function */ |
| 1487 | if (PL_op->op_private & OPpSORT_INPLACE) { |
| 1488 | assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV); |
| 1489 | (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */ |
| 1490 | av = (AV*)(*SP); |
| 1491 | max = AvFILL(av) + 1; |
| 1492 | if (SvMAGICAL(av)) { |
| 1493 | MEXTEND(SP, max); |
| 1494 | p2 = SP; |
| 1495 | for (i=0; i < (U32)max; i++) { |
| 1496 | SV **svp = av_fetch(av, i, FALSE); |
| 1497 | *SP++ = (svp) ? *svp : Nullsv; |
| 1498 | } |
| 1499 | } |
| 1500 | else { |
| 1501 | p1 = p2 = AvARRAY(av); |
| 1502 | sorting_av = 1; |
| 1503 | } |
| 1504 | } |
| 1505 | else { |
| 1506 | p2 = MARK+1; |
| 1507 | max = SP - MARK; |
| 1508 | } |
| 1509 | |
| 1510 | /* shuffle stack down, removing optional initial cv (p1!=p2), plus any |
| 1511 | * nulls; also stringify any args */ |
| 1512 | for (i=max; i > 0 ; i--) { |
| 1513 | if ((*p1 = *p2++)) { /* Weed out nulls. */ |
| 1514 | SvTEMP_off(*p1); |
| 1515 | if (!PL_sortcop && !SvPOK(*p1)) { |
| 1516 | STRLEN n_a; |
| 1517 | if (SvAMAGIC(*p1)) |
| 1518 | overloading = 1; |
| 1519 | else |
| 1520 | (void)sv_2pv(*p1, &n_a); |
| 1521 | } |
| 1522 | p1++; |
| 1523 | } |
| 1524 | else |
| 1525 | max--; |
| 1526 | } |
| 1527 | if (sorting_av) |
| 1528 | AvFILLp(av) = max-1; |
| 1529 | |
| 1530 | if (max > 1) { |
| 1531 | if (PL_sortcop) { |
| 1532 | PERL_CONTEXT *cx; |
| 1533 | SV** newsp; |
| 1534 | bool oldcatch = CATCH_GET; |
| 1535 | |
| 1536 | SAVETMPS; |
| 1537 | SAVEOP(); |
| 1538 | |
| 1539 | CATCH_SET(TRUE); |
| 1540 | PUSHSTACKi(PERLSI_SORT); |
| 1541 | if (!hasargs && !is_xsub) { |
| 1542 | if (PL_sortstash != stash || !PL_firstgv || !PL_secondgv) { |
| 1543 | SAVESPTR(PL_firstgv); |
| 1544 | SAVESPTR(PL_secondgv); |
| 1545 | PL_firstgv = gv_fetchpv("a", TRUE, SVt_PV); |
| 1546 | PL_secondgv = gv_fetchpv("b", TRUE, SVt_PV); |
| 1547 | PL_sortstash = stash; |
| 1548 | } |
| 1549 | SAVESPTR(GvSV(PL_firstgv)); |
| 1550 | SAVESPTR(GvSV(PL_secondgv)); |
| 1551 | } |
| 1552 | |
| 1553 | PUSHBLOCK(cx, CXt_NULL, PL_stack_base); |
| 1554 | if (!(PL_op->op_flags & OPf_SPECIAL)) { |
| 1555 | cx->cx_type = CXt_SUB; |
| 1556 | cx->blk_gimme = G_SCALAR; |
| 1557 | PUSHSUB(cx); |
| 1558 | } |
| 1559 | PL_sortcxix = cxstack_ix; |
| 1560 | |
| 1561 | if (hasargs && !is_xsub) { |
| 1562 | /* This is mostly copied from pp_entersub */ |
| 1563 | AV *av = (AV*)PAD_SVl(0); |
| 1564 | |
| 1565 | cx->blk_sub.savearray = GvAV(PL_defgv); |
| 1566 | GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av); |
| 1567 | CX_CURPAD_SAVE(cx->blk_sub); |
| 1568 | cx->blk_sub.argarray = av; |
| 1569 | } |
| 1570 | sortsv(p1-max, max, |
| 1571 | is_xsub ? sortcv_xsub : hasargs ? sortcv_stacked : sortcv); |
| 1572 | |
| 1573 | POPBLOCK(cx,PL_curpm); |
| 1574 | PL_stack_sp = newsp; |
| 1575 | POPSTACK; |
| 1576 | CATCH_SET(oldcatch); |
| 1577 | } |
| 1578 | else { |
| 1579 | MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */ |
| 1580 | sortsv(sorting_av ? AvARRAY(av) : ORIGMARK+1, max, |
| 1581 | (PL_op->op_private & OPpSORT_NUMERIC) |
| 1582 | ? ( (PL_op->op_private & OPpSORT_INTEGER) |
| 1583 | ? ( overloading ? amagic_i_ncmp : sv_i_ncmp) |
| 1584 | : ( overloading ? amagic_ncmp : sv_ncmp)) |
| 1585 | : ( IN_LOCALE_RUNTIME |
| 1586 | ? ( overloading |
| 1587 | ? amagic_cmp_locale |
| 1588 | : sv_cmp_locale_static) |
| 1589 | : ( overloading ? amagic_cmp : sv_cmp_static))); |
| 1590 | if (PL_op->op_private & OPpSORT_REVERSE) { |
| 1591 | SV **p = sorting_av ? AvARRAY(av) : ORIGMARK+1; |
| 1592 | SV **q = p+max-1; |
| 1593 | while (p < q) { |
| 1594 | SV *tmp = *p; |
| 1595 | *p++ = *q; |
| 1596 | *q-- = tmp; |
| 1597 | } |
| 1598 | } |
| 1599 | } |
| 1600 | } |
| 1601 | if (av && !sorting_av) { |
| 1602 | /* simulate pp_aassign of tied AV */ |
| 1603 | SV *sv; |
| 1604 | SV** base, **didstore; |
| 1605 | for (base = ORIGMARK+1, i=0; i < max; i++) { |
| 1606 | sv = NEWSV(28,0); |
| 1607 | sv_setsv(sv, base[i]); |
| 1608 | base[i] = sv; |
| 1609 | } |
| 1610 | av_clear(av); |
| 1611 | av_extend(av, max); |
| 1612 | for (i=0; i < max; i++) { |
| 1613 | sv = base[i]; |
| 1614 | didstore = av_store(av, i, sv); |
| 1615 | if (SvSMAGICAL(sv)) |
| 1616 | mg_set(sv); |
| 1617 | if (!didstore) |
| 1618 | sv_2mortal(sv); |
| 1619 | } |
| 1620 | } |
| 1621 | LEAVE; |
| 1622 | PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max); |
| 1623 | return nextop; |
| 1624 | } |
| 1625 | |
| 1626 | static I32 |
| 1627 | sortcv(pTHX_ SV *a, SV *b) |
| 1628 | { |
| 1629 | I32 oldsaveix = PL_savestack_ix; |
| 1630 | I32 oldscopeix = PL_scopestack_ix; |
| 1631 | I32 result; |
| 1632 | GvSV(PL_firstgv) = a; |
| 1633 | GvSV(PL_secondgv) = b; |
| 1634 | PL_stack_sp = PL_stack_base; |
| 1635 | PL_op = PL_sortcop; |
| 1636 | CALLRUNOPS(aTHX); |
| 1637 | if (PL_stack_sp != PL_stack_base + 1) |
| 1638 | Perl_croak(aTHX_ "Sort subroutine didn't return single value"); |
| 1639 | if (!SvNIOKp(*PL_stack_sp)) |
| 1640 | Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value"); |
| 1641 | result = SvIV(*PL_stack_sp); |
| 1642 | while (PL_scopestack_ix > oldscopeix) { |
| 1643 | LEAVE; |
| 1644 | } |
| 1645 | leave_scope(oldsaveix); |
| 1646 | return result; |
| 1647 | } |
| 1648 | |
| 1649 | static I32 |
| 1650 | sortcv_stacked(pTHX_ SV *a, SV *b) |
| 1651 | { |
| 1652 | I32 oldsaveix = PL_savestack_ix; |
| 1653 | I32 oldscopeix = PL_scopestack_ix; |
| 1654 | I32 result; |
| 1655 | AV *av; |
| 1656 | |
| 1657 | av = GvAV(PL_defgv); |
| 1658 | |
| 1659 | if (AvMAX(av) < 1) { |
| 1660 | SV** ary = AvALLOC(av); |
| 1661 | if (AvARRAY(av) != ary) { |
| 1662 | AvMAX(av) += AvARRAY(av) - AvALLOC(av); |
| 1663 | SvPVX(av) = (char*)ary; |
| 1664 | } |
| 1665 | if (AvMAX(av) < 1) { |
| 1666 | AvMAX(av) = 1; |
| 1667 | Renew(ary,2,SV*); |
| 1668 | SvPVX(av) = (char*)ary; |
| 1669 | } |
| 1670 | } |
| 1671 | AvFILLp(av) = 1; |
| 1672 | |
| 1673 | AvARRAY(av)[0] = a; |
| 1674 | AvARRAY(av)[1] = b; |
| 1675 | PL_stack_sp = PL_stack_base; |
| 1676 | PL_op = PL_sortcop; |
| 1677 | CALLRUNOPS(aTHX); |
| 1678 | if (PL_stack_sp != PL_stack_base + 1) |
| 1679 | Perl_croak(aTHX_ "Sort subroutine didn't return single value"); |
| 1680 | if (!SvNIOKp(*PL_stack_sp)) |
| 1681 | Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value"); |
| 1682 | result = SvIV(*PL_stack_sp); |
| 1683 | while (PL_scopestack_ix > oldscopeix) { |
| 1684 | LEAVE; |
| 1685 | } |
| 1686 | leave_scope(oldsaveix); |
| 1687 | return result; |
| 1688 | } |
| 1689 | |
| 1690 | static I32 |
| 1691 | sortcv_xsub(pTHX_ SV *a, SV *b) |
| 1692 | { |
| 1693 | dSP; |
| 1694 | I32 oldsaveix = PL_savestack_ix; |
| 1695 | I32 oldscopeix = PL_scopestack_ix; |
| 1696 | I32 result; |
| 1697 | CV *cv=(CV*)PL_sortcop; |
| 1698 | |
| 1699 | SP = PL_stack_base; |
| 1700 | PUSHMARK(SP); |
| 1701 | EXTEND(SP, 2); |
| 1702 | *++SP = a; |
| 1703 | *++SP = b; |
| 1704 | PUTBACK; |
| 1705 | (void)(*CvXSUB(cv))(aTHX_ cv); |
| 1706 | if (PL_stack_sp != PL_stack_base + 1) |
| 1707 | Perl_croak(aTHX_ "Sort subroutine didn't return single value"); |
| 1708 | if (!SvNIOKp(*PL_stack_sp)) |
| 1709 | Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value"); |
| 1710 | result = SvIV(*PL_stack_sp); |
| 1711 | while (PL_scopestack_ix > oldscopeix) { |
| 1712 | LEAVE; |
| 1713 | } |
| 1714 | leave_scope(oldsaveix); |
| 1715 | return result; |
| 1716 | } |
| 1717 | |
| 1718 | |
| 1719 | static I32 |
| 1720 | sv_ncmp(pTHX_ SV *a, SV *b) |
| 1721 | { |
| 1722 | NV nv1 = SvNV(a); |
| 1723 | NV nv2 = SvNV(b); |
| 1724 | return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0; |
| 1725 | } |
| 1726 | |
| 1727 | static I32 |
| 1728 | sv_i_ncmp(pTHX_ SV *a, SV *b) |
| 1729 | { |
| 1730 | IV iv1 = SvIV(a); |
| 1731 | IV iv2 = SvIV(b); |
| 1732 | return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0; |
| 1733 | } |
| 1734 | #define tryCALL_AMAGICbin(left,right,meth,svp) STMT_START { \ |
| 1735 | *svp = Nullsv; \ |
| 1736 | if (PL_amagic_generation) { \ |
| 1737 | if (SvAMAGIC(left)||SvAMAGIC(right))\ |
| 1738 | *svp = amagic_call(left, \ |
| 1739 | right, \ |
| 1740 | CAT2(meth,_amg), \ |
| 1741 | 0); \ |
| 1742 | } \ |
| 1743 | } STMT_END |
| 1744 | |
| 1745 | static I32 |
| 1746 | amagic_ncmp(pTHX_ register SV *a, register SV *b) |
| 1747 | { |
| 1748 | SV *tmpsv; |
| 1749 | tryCALL_AMAGICbin(a,b,ncmp,&tmpsv); |
| 1750 | if (tmpsv) { |
| 1751 | NV d; |
| 1752 | |
| 1753 | if (SvIOK(tmpsv)) { |
| 1754 | I32 i = SvIVX(tmpsv); |
| 1755 | if (i > 0) |
| 1756 | return 1; |
| 1757 | return i? -1 : 0; |
| 1758 | } |
| 1759 | d = SvNV(tmpsv); |
| 1760 | if (d > 0) |
| 1761 | return 1; |
| 1762 | return d? -1 : 0; |
| 1763 | } |
| 1764 | return sv_ncmp(aTHX_ a, b); |
| 1765 | } |
| 1766 | |
| 1767 | static I32 |
| 1768 | amagic_i_ncmp(pTHX_ register SV *a, register SV *b) |
| 1769 | { |
| 1770 | SV *tmpsv; |
| 1771 | tryCALL_AMAGICbin(a,b,ncmp,&tmpsv); |
| 1772 | if (tmpsv) { |
| 1773 | NV d; |
| 1774 | |
| 1775 | if (SvIOK(tmpsv)) { |
| 1776 | I32 i = SvIVX(tmpsv); |
| 1777 | if (i > 0) |
| 1778 | return 1; |
| 1779 | return i? -1 : 0; |
| 1780 | } |
| 1781 | d = SvNV(tmpsv); |
| 1782 | if (d > 0) |
| 1783 | return 1; |
| 1784 | return d? -1 : 0; |
| 1785 | } |
| 1786 | return sv_i_ncmp(aTHX_ a, b); |
| 1787 | } |
| 1788 | |
| 1789 | static I32 |
| 1790 | amagic_cmp(pTHX_ register SV *str1, register SV *str2) |
| 1791 | { |
| 1792 | SV *tmpsv; |
| 1793 | tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv); |
| 1794 | if (tmpsv) { |
| 1795 | NV d; |
| 1796 | |
| 1797 | if (SvIOK(tmpsv)) { |
| 1798 | I32 i = SvIVX(tmpsv); |
| 1799 | if (i > 0) |
| 1800 | return 1; |
| 1801 | return i? -1 : 0; |
| 1802 | } |
| 1803 | d = SvNV(tmpsv); |
| 1804 | if (d > 0) |
| 1805 | return 1; |
| 1806 | return d? -1 : 0; |
| 1807 | } |
| 1808 | return sv_cmp(str1, str2); |
| 1809 | } |
| 1810 | |
| 1811 | static I32 |
| 1812 | amagic_cmp_locale(pTHX_ register SV *str1, register SV *str2) |
| 1813 | { |
| 1814 | SV *tmpsv; |
| 1815 | tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv); |
| 1816 | if (tmpsv) { |
| 1817 | NV d; |
| 1818 | |
| 1819 | if (SvIOK(tmpsv)) { |
| 1820 | I32 i = SvIVX(tmpsv); |
| 1821 | if (i > 0) |
| 1822 | return 1; |
| 1823 | return i? -1 : 0; |
| 1824 | } |
| 1825 | d = SvNV(tmpsv); |
| 1826 | if (d > 0) |
| 1827 | return 1; |
| 1828 | return d? -1 : 0; |
| 1829 | } |
| 1830 | return sv_cmp_locale(str1, str2); |
| 1831 | } |