2
* Copyright (c) 1992, 1993
3
* The Regents of the University of California. All rights reserved.
5
* Redistribution and use in source and binary forms, with or without
6
* modification, are permitted provided that the following conditions
8
* 1. Redistributions of source code must retain the above copyright
9
* notice, this list of conditions and the following disclaimer.
10
* 2. Redistributions in binary form must reproduce the above copyright
11
* notice, this list of conditions and the following disclaimer in the
12
* documentation and/or other materials provided with the distribution.
13
* 3. All advertising materials mentioning features or use of this software
14
* must display the following acknowledgement:
15
* This product includes software developed by the University of
16
* California, Berkeley and its contributors.
17
* 4. Neither the name of the University nor the names of its contributors
18
* may be used to endorse or promote products derived from this software
19
* without specific prior written permission.
21
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34
#if defined(LIBC_SCCS) && !defined(lint)
35
static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
36
#endif /* LIBC_SCCS and not lint */
38
#include <sys/types.h>
41
#if !defined (WIN32) || !defined (min)
42
#define min(a, b) (a) < (b) ? a : b
46
* Quicksort routine from Bentley & McIlroy's "Engineering a Sort Function".
48
#define swapcode(TYPE, parmi, parmj, n) { \
49
long i = (n) / sizeof (TYPE); \
50
register TYPE *pi = (TYPE *) (parmi); \
51
register TYPE *pj = (TYPE *) (parmj); \
53
register TYPE t = *pi; \
59
#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
60
es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
63
swapfunc(a, b, n, swaptype)
68
swapcode(long, a, b, n)
70
swapcode(char, a, b, n)
74
if (swaptype == 0) { \
75
long t = *(long *)(a); \
76
*(long *)(a) = *(long *)(b); \
79
swapfunc(a, b, es, swaptype)
81
#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
83
static char* med3(a, b, c, cmp)
87
return cmp(a, b) < 0 ?
88
(cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
89
:(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
92
void quicksort(void *a, size_t n, size_t es,
93
int (*compare_function) (const void *p1, const void *p2))
95
char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
96
int d, r, swaptype, swap_cnt;
98
loop: SWAPINIT(a, es);
101
for (pm = (char*)((unsigned long)a + es);
102
pm < (char *) ((unsigned long)a + n * es);
104
for (pl = pm; pl > (char *) a && compare_function(pl - es, pl) > 0;
109
pm = (char*)((unsigned long)a + (n / 2) * es);
112
pn = (char*)((unsigned long)a + (n - 1) * es);
115
pl = med3(pl, pl + d, pl + 2 * d, compare_function);
116
pm = med3(pm - d, pm, pm + d, compare_function);
117
pn = med3(pn - 2 * d, pn - d, pn, compare_function);
119
pm = med3(pl, pm, pn, compare_function);
122
pa = pb = (char*)((unsigned long)a + es);
124
pc = pd = (char*)((unsigned long)a + (n - 1) * es);
126
while (pb <= pc && (r = compare_function(pb, a)) <= 0) {
134
while (pb <= pc && (r = compare_function(pc, a)) >= 0) {
149
if (swap_cnt == 0) { /* Switch to insertion sort */
150
for (pm = (char*)((unsigned long)a + es); pm < (char *) a + n * es; pm += es)
151
for (pl = pm; pl > (char *) a && compare_function(pl - es, pl) > 0;
157
pn = (char*)((unsigned long)a + n * es);
158
r = min(pa - (char *)a, pb - pa);
159
vecswap(a, pb - r, r);
160
r = min(pd - pc, pn - pd - es);
161
vecswap(pb, pn - r, r);
162
if ((r = pb - pa) > es)
163
quicksort(a, r / es, es, compare_function);
164
if ((r = pd - pc) > es) {
165
/* Iterate rather than recurse to save stack space */
170
/* quicksort(pn - r, r / es, es, compare_function);*/