| /*- |
| * SPDX-License-Identifier: BSD-3-Clause |
| * |
| * Copyright (c) 1992, 1993 |
| * The Regents of the University of California. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of the University nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #if defined(LIBC_SCCS) && !defined(lint) |
| static const char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93"; |
| #endif /* LIBC_SCCS and not lint */ |
| #include <sys/cdefs.h> |
| #include <stdlib.h> |
| |
| #ifdef I_AM_QSORT_R |
| typedef int cmp_t(void *, const void *, const void *); |
| #else |
| typedef int cmp_t(const void *, const void *); |
| #endif |
| static inline char *med3(char *, char *, char *, cmp_t *, void *); |
| |
| #define MIN(a, b) ((a) < (b) ? a : b) |
| |
| /* |
| * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". |
| */ |
| |
| static inline void |
| swapfunc(char *a, char *b, size_t es) |
| { |
| char t; |
| |
| do { |
| t = *a; |
| *a++ = *b; |
| *b++ = t; |
| } while (--es > 0); |
| } |
| |
| #define vecswap(a, b, n) \ |
| do { \ |
| if ((n) > 0) { \ |
| swapfunc(a, b, n); \ |
| } \ |
| } while (0) |
| |
| #ifdef I_AM_QSORT_R |
| #define CMP(t, x, y) (cmp((t), (x), (y))) |
| #else |
| #define CMP(t, x, y) (cmp((x), (y))) |
| #endif |
| |
| static inline char * |
| med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk) |
| { |
| return CMP(thunk, a, b) < 0 ? |
| (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a)) |
| : (CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c)); |
| } |
| |
| #ifdef I_AM_QSORT_R |
| void qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) |
| #else |
| #define thunk NULL |
| void qsort(void *a, size_t n, size_t es, cmp_t *cmp) |
| #endif |
| { |
| char *pa, *pb, *pc, *pd, *pl, *pm, *pn; |
| size_t d1, d2; |
| int cmp_result; |
| int swap_cnt; |
| |
| loop: |
| swap_cnt = 0; |
| if (n < 7) { |
| for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) |
| for (pl = pm; |
| pl > (char *)a && CMP(thunk, pl - es, pl) > 0; |
| pl -= es) |
| swapfunc(pl, pl - es, es); |
| return; |
| } |
| pm = (char *)a + (n / 2) * es; |
| if (n > 7) { |
| pl = a; |
| pn = (char *)a + (n - 1) * es; |
| if (n > 40) { |
| size_t d = (n / 8) * es; |
| |
| pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); |
| pm = med3(pm - d, pm, pm + d, cmp, thunk); |
| pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); |
| } |
| pm = med3(pl, pm, pn, cmp, thunk); |
| } |
| swapfunc(a, pm, es); |
| pa = pb = (char *)a + es; |
| |
| pc = pd = (char *)a + (n - 1) * es; |
| for (;;) { |
| while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { |
| if (cmp_result == 0) { |
| swap_cnt = 1; |
| swapfunc(pa, pb, es); |
| pa += es; |
| } |
| pb += es; |
| } |
| while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { |
| if (cmp_result == 0) { |
| swap_cnt = 1; |
| swapfunc(pc, pd, es); |
| pd -= es; |
| } |
| pc -= es; |
| } |
| if (pb > pc) |
| break; |
| swapfunc(pb, pc, es); |
| swap_cnt = 1; |
| pb += es; |
| pc -= es; |
| } |
| if (swap_cnt == 0) { /* Switch to insertion sort */ |
| for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) |
| for (pl = pm; |
| pl > (char *)a && CMP(thunk, pl - es, pl) > 0; |
| pl -= es) |
| swapfunc(pl, pl - es, es); |
| return; |
| } |
| |
| pn = (char *)a + n * es; |
| d1 = MIN(pa - (char *)a, pb - pa); |
| vecswap(a, pb - d1, d1); |
| d1 = MIN(pd - pc, pn - pd - es); |
| vecswap(pb, pn - d1, d1); |
| |
| d1 = pb - pa; |
| d2 = pd - pc; |
| if (d1 <= d2) { |
| /* Recurse on left partition, then iterate on right partition */ |
| if (d1 > es) { |
| #ifdef I_AM_QSORT_R |
| qsort_r(a, d1 / es, es, thunk, cmp); |
| #else |
| qsort(a, d1 / es, es, cmp); |
| #endif |
| } |
| if (d2 > es) { |
| /* Iterate rather than recurse to save stack space */ |
| /* qsort(pn - d2, d2 / es, es, cmp); */ |
| a = pn - d2; |
| n = d2 / es; |
| goto loop; |
| } |
| } else { |
| /* Recurse on right partition, then iterate on left partition */ |
| if (d2 > es) { |
| #ifdef I_AM_QSORT_R |
| qsort_r(pn - d2, d2 / es, es, thunk, cmp); |
| #else |
| qsort(pn - d2, d2 / es, es, cmp); |
| #endif |
| } |
| if (d1 > es) { |
| /* Iterate rather than recurse to save stack space */ |
| /* qsort(a, d1 / es, es, cmp); */ |
| n = d1 / es; |
| goto loop; |
| } |
| } |
| } |