1 /* $NetBSD: qsort.c,v 1.1.1.2 2014/04/24 12:45:52 pettai Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #if 0
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 #endif
39
40 #include <config.h>
41
42 #ifdef NEED_QSORT
43
44 #include <krb5/roken.h>
45
46 #include <stdlib.h>
47
48 #ifdef I_AM_QSORT_R
49 typedef int cmp_t(void *, const void *, const void *);
50 #else
51 typedef int cmp_t(const void *, const void *);
52 #endif
53 static inline char *med3(char *, char *, char *, cmp_t *, void *);
54 static inline void swapfunc(char *, char *, int, int);
55
56 /*
57 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
58 */
59 #define swapcode(TYPE, parmi, parmj, n) { \
60 long i = (n) / sizeof (TYPE); \
61 TYPE *pi = (TYPE *) (parmi); \
62 TYPE *pj = (TYPE *) (parmj); \
63 do { \
64 TYPE t = *pi; \
65 *pi++ = *pj; \
66 *pj++ = t; \
67 } while (--i > 0); \
68 }
69
70 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
71 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
72
73 static inline void
swapfunc(a,b,n,swaptype)74 swapfunc(a, b, n, swaptype)
75 char *a, *b;
76 int n, swaptype;
77 {
78 if(swaptype <= 1)
79 swapcode(long, a, b, n)
80 else
81 swapcode(char, a, b, n)
82 }
83
84 #define swap(a, b) \
85 if (swaptype == 0) { \
86 long t = *(long *)(a); \
87 *(long *)(a) = *(long *)(b); \
88 *(long *)(b) = t; \
89 } else \
90 swapfunc(a, b, es, swaptype)
91
92 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
93
94 #ifdef I_AM_QSORT_R
95 #define CMP(t, x, y) (cmp((t), (x), (y)))
96 #else
97 #define CMP(t, x, y) (cmp((x), (y)))
98 #endif
99
100 static inline char *
med3(char * a,char * b,char * c,cmp_t * cmp,void * thunk)101 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
102 #ifndef I_AM_QSORT_R
103 /* __unused */
104 #endif
105 )
106 {
107 return CMP(thunk, a, b) < 0 ?
108 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
109 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
110 }
111
112 #ifdef I_AM_QSORT_R
113 void
rk_qsort_r(void * a,size_t n,size_t es,void * thunk,cmp_t * cmp)114 rk_qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
115 #else
116 #define thunk NULL
117 void
118 rk_qsort(void *a, size_t n, size_t es, cmp_t *cmp)
119 #endif
120 {
121 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
122 size_t d, r;
123 int cmp_result;
124 int swaptype, swap_cnt;
125
126 loop: SWAPINIT(a, es);
127 swap_cnt = 0;
128 if (n < 7) {
129 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
130 for (pl = pm;
131 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
132 pl -= es)
133 swap(pl, pl - es);
134 return;
135 }
136 pm = (char *)a + (n / 2) * es;
137 if (n > 7) {
138 pl = a;
139 pn = (char *)a + (n - 1) * es;
140 if (n > 40) {
141 d = (n / 8) * es;
142 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
143 pm = med3(pm - d, pm, pm + d, cmp, thunk);
144 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
145 }
146 pm = med3(pl, pm, pn, cmp, thunk);
147 }
148 swap(a, pm);
149 pa = pb = (char *)a + es;
150
151 pc = pd = (char *)a + (n - 1) * es;
152 for (;;) {
153 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
154 if (cmp_result == 0) {
155 swap_cnt = 1;
156 swap(pa, pb);
157 pa += es;
158 }
159 pb += es;
160 }
161 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
162 if (cmp_result == 0) {
163 swap_cnt = 1;
164 swap(pc, pd);
165 pd -= es;
166 }
167 pc -= es;
168 }
169 if (pb > pc)
170 break;
171 swap(pb, pc);
172 swap_cnt = 1;
173 pb += es;
174 pc -= es;
175 }
176 if (swap_cnt == 0) { /* Switch to insertion sort */
177 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
178 for (pl = pm;
179 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
180 pl -= es)
181 swap(pl, pl - es);
182 return;
183 }
184
185 pn = (char *)a + n * es;
186 r = min(pa - (char *)a, pb - pa);
187 vecswap(a, pb - r, r);
188 r = min(pd - pc, pn - pd - es);
189 vecswap(pb, pn - r, r);
190 if ((r = pb - pa) > es)
191 #ifdef I_AM_QSORT_R
192 rk_qsort_r(a, r / es, es, thunk, cmp);
193 #else
194 rk_qsort(a, r / es, es, cmp);
195 #endif
196 if ((r = pd - pc) > es) {
197 /* Iterate rather than recurse to save stack space */
198 a = pn - r;
199 n = r / es;
200 goto loop;
201 }
202 /* rk_qsort(pn - r, r / es, es, cmp);*/
203 }
204
205 #endif /* NEED_QSORT */
206