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-rw-r--r--src/lib/libc/stdlib/qsort.c164
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diff --git a/src/lib/libc/stdlib/qsort.c b/src/lib/libc/stdlib/qsort.c
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1/*-
2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char *rcsid = "$OpenBSD: qsort.c,v 1.9 2005/03/30 18:51:49 pat Exp $";
32#endif /* LIBC_SCCS and not lint */
33
34#include <sys/types.h>
35#include <stdlib.h>
36
37static __inline char *med3(char *, char *, char *, int (*)(const void *, const void *));
38static __inline void swapfunc(char *, char *, int, int);
39
40#define min(a, b) (a) < (b) ? a : b
41
42/*
43 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
44 */
45#define swapcode(TYPE, parmi, parmj, n) { \
46 long i = (n) / sizeof (TYPE); \
47 TYPE *pi = (TYPE *) (parmi); \
48 TYPE *pj = (TYPE *) (parmj); \
49 do { \
50 TYPE t = *pi; \
51 *pi++ = *pj; \
52 *pj++ = t; \
53 } while (--i > 0); \
54}
55
56#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
57 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
58
59static __inline void
60swapfunc(char *a, char *b, int n, int swaptype)
61{
62 if (swaptype <= 1)
63 swapcode(long, a, b, n)
64 else
65 swapcode(char, a, b, n)
66}
67
68#define swap(a, b) \
69 if (swaptype == 0) { \
70 long t = *(long *)(a); \
71 *(long *)(a) = *(long *)(b); \
72 *(long *)(b) = t; \
73 } else \
74 swapfunc(a, b, es, swaptype)
75
76#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
77
78static __inline char *
79med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
80{
81 return cmp(a, b) < 0 ?
82 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
83 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
84}
85
86void
87qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
88{
89 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
90 int d, r, swaptype, swap_cnt;
91 char *a = aa;
92
93loop: SWAPINIT(a, es);
94 swap_cnt = 0;
95 if (n < 7) {
96 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
97 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
98 pl -= es)
99 swap(pl, pl - es);
100 return;
101 }
102 pm = (char *)a + (n / 2) * es;
103 if (n > 7) {
104 pl = (char *)a;
105 pn = (char *)a + (n - 1) * es;
106 if (n > 40) {
107 d = (n / 8) * es;
108 pl = med3(pl, pl + d, pl + 2 * d, cmp);
109 pm = med3(pm - d, pm, pm + d, cmp);
110 pn = med3(pn - 2 * d, pn - d, pn, cmp);
111 }
112 pm = med3(pl, pm, pn, cmp);
113 }
114 swap(a, pm);
115 pa = pb = (char *)a + es;
116
117 pc = pd = (char *)a + (n - 1) * es;
118 for (;;) {
119 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
120 if (r == 0) {
121 swap_cnt = 1;
122 swap(pa, pb);
123 pa += es;
124 }
125 pb += es;
126 }
127 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
128 if (r == 0) {
129 swap_cnt = 1;
130 swap(pc, pd);
131 pd -= es;
132 }
133 pc -= es;
134 }
135 if (pb > pc)
136 break;
137 swap(pb, pc);
138 swap_cnt = 1;
139 pb += es;
140 pc -= es;
141 }
142 if (swap_cnt == 0) { /* Switch to insertion sort */
143 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
144 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
145 pl -= es)
146 swap(pl, pl - es);
147 return;
148 }
149
150 pn = (char *)a + n * es;
151 r = min(pa - (char *)a, pb - pa);
152 vecswap(a, pb - r, r);
153 r = min(pd - pc, pn - pd - es);
154 vecswap(pb, pn - r, r);
155 if ((r = pb - pa) > es)
156 qsort(a, r / es, es, cmp);
157 if ((r = pd - pc) > es) {
158 /* Iterate rather than recurse to save stack space */
159 a = pn - r;
160 n = r / es;
161 goto loop;
162 }
163/* qsort(pn - r, r / es, es, cmp);*/
164}
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