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-rw-r--r--src/lib/libc/stdlib/qsort.c171
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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 1.8 2003/06/02 20:18:38 millert 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 (*)());
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 register TYPE *pi = (TYPE *) (parmi); \
48 register TYPE *pj = (TYPE *) (parmj); \
49 do { \
50 register 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(a, b, n, swaptype)
61 char *a, *b;
62 int n, swaptype;
63{
64 if (swaptype <= 1)
65 swapcode(long, a, b, n)
66 else
67 swapcode(char, a, b, n)
68}
69
70#define swap(a, b) \
71 if (swaptype == 0) { \
72 long t = *(long *)(a); \
73 *(long *)(a) = *(long *)(b); \
74 *(long *)(b) = t; \
75 } else \
76 swapfunc(a, b, es, swaptype)
77
78#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
79
80static __inline char *
81med3(a, b, c, cmp)
82 char *a, *b, *c;
83 int (*cmp)();
84{
85 return cmp(a, b) < 0 ?
86 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
87 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
88}
89
90void
91qsort(aa, n, es, cmp)
92 void *aa;
93 size_t n, es;
94 int (*cmp)();
95{
96 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
97 int d, r, swaptype, swap_cnt;
98 register char *a = aa;
99
100loop: SWAPINIT(a, es);
101 swap_cnt = 0;
102 if (n < 7) {
103 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
104 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
105 pl -= es)
106 swap(pl, pl - es);
107 return;
108 }
109 pm = (char *)a + (n / 2) * es;
110 if (n > 7) {
111 pl = (char *)a;
112 pn = (char *)a + (n - 1) * es;
113 if (n > 40) {
114 d = (n / 8) * es;
115 pl = med3(pl, pl + d, pl + 2 * d, cmp);
116 pm = med3(pm - d, pm, pm + d, cmp);
117 pn = med3(pn - 2 * d, pn - d, pn, cmp);
118 }
119 pm = med3(pl, pm, pn, cmp);
120 }
121 swap(a, pm);
122 pa = pb = (char *)a + es;
123
124 pc = pd = (char *)a + (n - 1) * es;
125 for (;;) {
126 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
127 if (r == 0) {
128 swap_cnt = 1;
129 swap(pa, pb);
130 pa += es;
131 }
132 pb += es;
133 }
134 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
135 if (r == 0) {
136 swap_cnt = 1;
137 swap(pc, pd);
138 pd -= es;
139 }
140 pc -= es;
141 }
142 if (pb > pc)
143 break;
144 swap(pb, pc);
145 swap_cnt = 1;
146 pb += es;
147 pc -= es;
148 }
149 if (swap_cnt == 0) { /* Switch to insertion sort */
150 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
151 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
152 pl -= es)
153 swap(pl, pl - es);
154 return;
155 }
156
157 pn = (char *)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 qsort(a, r / es, es, cmp);
164 if ((r = pd - pc) > es) {
165 /* Iterate rather than recurse to save stack space */
166 a = pn - r;
167 n = r / es;
168 goto loop;
169 }
170/* qsort(pn - r, r / es, es, cmp);*/
171}
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