1 /*
2 * qsort taken from FreeBSD, slightly modified to match glibc's
3 * argument ordering
4 */
5
6 /* FIXME: should use mergesort instead */
7
8 /*-
9 * Copyright (c) 1992, 1993
10 * The Regents of the University of California. All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #ifndef _WIN32
41 #include <sys/cdefs.h>
42 #endif
43
44 /* $FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.13.2.1.8.1 2010/12/21 17:10:29 kensmith Exp $ */
45
46 #include <stdlib.h>
47
48 typedef int cmp_t(const void *, const void *, void *);
49 static inline char *med3(char *, char *, char *, cmp_t *, void *);
50 static inline void swapfunc(char *, char *, int, int);
51
52 #ifndef min
53 #define min(a, b) (a) < (b) ? a : b
54 #endif
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 #define CMP(t, x, y) (cmp((x), (y), (t)))
95
96 static inline char *
med3(char * a,char * b,char * c,cmp_t * cmp,void * thunk)97 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk)
98 {
99 return CMP(thunk, a, b) < 0 ?
100 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
101 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
102 }
103
104 void
solv_sort(void * a,size_t n,size_t es,cmp_t * cmp,void * thunk)105 solv_sort(void *a, size_t n, size_t es, cmp_t *cmp, void *thunk)
106 {
107 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
108 size_t d, r;
109 int cmp_result;
110 int swaptype, swap_cnt;
111
112 loop: SWAPINIT(a, es);
113 swap_cnt = 0;
114 if (n < 7) {
115 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
116 for (pl = pm;
117 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
118 pl -= es)
119 swap(pl, pl - es);
120 return;
121 }
122 pm = (char *)a + (n / 2) * es;
123 if (n > 7) {
124 pl = a;
125 pn = (char *)a + (n - 1) * es;
126 if (n > 40) {
127 d = (n / 8) * es;
128 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
129 pm = med3(pm - d, pm, pm + d, cmp, thunk);
130 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
131 }
132 pm = med3(pl, pm, pn, cmp, thunk);
133 }
134 swap(a, pm);
135 pa = pb = (char *)a + es;
136
137 pc = pd = (char *)a + (n - 1) * es;
138 for (;;) {
139 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
140 if (cmp_result == 0) {
141 swap_cnt = 1;
142 swap(pa, pb);
143 pa += es;
144 }
145 pb += es;
146 }
147 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
148 if (cmp_result == 0) {
149 swap_cnt = 1;
150 swap(pc, pd);
151 pd -= es;
152 }
153 pc -= es;
154 }
155 if (pb > pc)
156 break;
157 swap(pb, pc);
158 swap_cnt = 1;
159 pb += es;
160 pc -= es;
161 }
162 if (swap_cnt == 0) { /* Switch to insertion sort */
163 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
164 for (pl = pm;
165 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
166 pl -= es)
167 swap(pl, pl - es);
168 return;
169 }
170
171 pn = (char *)a + n * es;
172 r = min(pa - (char *)a, pb - pa);
173 vecswap(a, pb - r, r);
174 r = min(pd - pc, pn - pd - es);
175 vecswap(pb, pn - r, r);
176 if ((r = pb - pa) > es)
177 solv_sort(a, r / es, es, cmp, thunk);
178 if ((r = pd - pc) > es) {
179 /* Iterate rather than recurse to save stack space */
180 a = pn - r;
181 n = r / es;
182 goto loop;
183 }
184 /* qsort(pn - r, r / es, es, cmp);*/
185 }
186