xnu-2782.30.5.tar.gz
[apple/xnu.git] / bsd / kern / qsort.c
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1c79356b 1/*
2d21ac55 2 * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
5d5c5d0d 3 *
2d21ac55 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b 5 *
2d21ac55
A
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
8f6c56a5 14 *
2d21ac55
A
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5
A
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55
A
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
8f6c56a5 25 *
2d21ac55 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b
A
27 */
28/*
29 * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
30 *
31 * Copyright (c) 1992, 1993
32 * The Regents of the University of California. All rights reserved.
33 *
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
36 * are met:
37 * 1. Redistributions of source code must retain the above copyright
38 * notice, this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright
40 * notice, this list of conditions and the following disclaimer in the
41 * documentation and/or other materials provided with the distribution.
42 * 3. All advertising materials mentioning features or use of this software
43 * must display the following acknowledgement:
44 * This product includes software developed by the University of
45 * California, Berkeley and its contributors.
46 * 4. Neither the name of the University nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60 * SUCH DAMAGE.
61 *
62 * @(#)qsort.c 8.1 (Berkeley) 6/4/93
63 */
64
65
66#include <sys/types.h>
b4c24cb9 67//#include <stdlib.h>
b0d623f7
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68
69__private_extern__
70void
71qsort(void *a, size_t n, size_t es, int (*cmp)(const void *, const void *));
1c79356b 72
2d21ac55 73static inline char *med3(char *, char *, char *, int (*)(const void *, const void *));
91447636 74static inline void swapfunc(char *, char *, int, int);
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75
76#define min(a, b) (a) < (b) ? a : b
77
78/*
79 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
80 */
81#define swapcode(TYPE, parmi, parmj, n) { \
82 long i = (n) / sizeof (TYPE); \
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83 TYPE *pi = (TYPE *) (parmi); \
84 TYPE *pj = (TYPE *) (parmj); \
1c79356b 85 do { \
2d21ac55 86 TYPE t = *pi; \
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87 *pi++ = *pj; \
88 *pj++ = t; \
89 } while (--i > 0); \
90}
91
92#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
93 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
94
95static inline void
2d21ac55 96swapfunc(char *a, char *b, int n, int swaptype)
1c79356b
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97{
98 if(swaptype <= 1)
99 swapcode(long, a, b, n)
100 else
101 swapcode(char, a, b, n)
102}
103
104#define swap(a, b) \
105 if (swaptype == 0) { \
106 long t = *(long *)(a); \
107 *(long *)(a) = *(long *)(b); \
108 *(long *)(b) = t; \
109 } else \
110 swapfunc(a, b, es, swaptype)
111
112#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
113
114static inline char *
2d21ac55 115med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
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116{
117 return cmp(a, b) < 0 ?
118 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
119 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
120}
121
b4c24cb9 122__private_extern__
1c79356b 123void
2d21ac55 124qsort(void *a, size_t n, size_t es, int (*cmp)(const void *, const void *))
1c79356b
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125{
126 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
2d21ac55
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127 int d, swaptype, swap_cnt;
128 int r;
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129
130loop: SWAPINIT(a, es);
131 swap_cnt = 0;
132 if (n < 7) {
55e303ae 133 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
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134 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
135 pl -= es)
136 swap(pl, pl - es);
137 return;
138 }
55e303ae 139 pm = (char *)a + (n / 2) * es;
1c79356b
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140 if (n > 7) {
141 pl = a;
55e303ae 142 pn = (char *)a + (n - 1) * es;
1c79356b
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143 if (n > 40) {
144 d = (n / 8) * es;
145 pl = med3(pl, pl + d, pl + 2 * d, cmp);
146 pm = med3(pm - d, pm, pm + d, cmp);
147 pn = med3(pn - 2 * d, pn - d, pn, cmp);
148 }
149 pm = med3(pl, pm, pn, cmp);
150 }
151 swap(a, pm);
55e303ae 152 pa = pb = (char *)a + es;
1c79356b 153
55e303ae 154 pc = pd = (char *)a + (n - 1) * es;
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155 for (;;) {
156 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
157 if (r == 0) {
158 swap_cnt = 1;
159 swap(pa, pb);
160 pa += es;
161 }
162 pb += es;
163 }
164 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
165 if (r == 0) {
166 swap_cnt = 1;
167 swap(pc, pd);
168 pd -= es;
169 }
170 pc -= es;
171 }
172 if (pb > pc)
173 break;
174 swap(pb, pc);
175 swap_cnt = 1;
176 pb += es;
177 pc -= es;
178 }
179 if (swap_cnt == 0) { /* Switch to insertion sort */
55e303ae 180 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
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181 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
182 pl -= es)
183 swap(pl, pl - es);
184 return;
185 }
186
55e303ae 187 pn = (char *)a + n * es;
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188 r = min(pa - (char *)a, pb - pa);
189 vecswap(a, pb - r, r);
2d21ac55 190 r = min((size_t)(pd - pc), pn - pd - es);
1c79356b 191 vecswap(pb, pn - r, r);
2d21ac55 192 if ((size_t)(r = pb - pa) > es)
1c79356b 193 qsort(a, r / es, es, cmp);
2d21ac55 194 if ((size_t)(r = pd - pc) > es) {
1c79356b
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195 /* Iterate rather than recurse to save stack space */
196 a = pn - r;
197 n = r / es;
198 goto loop;
199 }
200/* qsort(pn - r, r / es, es, cmp);*/
201}