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 #include "yportenv.h"
31 //#include <linux/string.h>
32
33 /*
34 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
35 */
36 #define swapcode(TYPE, parmi, parmj, n) { \
37 long i = (n) / sizeof (TYPE); \
38 register TYPE *pi = (TYPE *) (parmi); \
39 register TYPE *pj = (TYPE *) (parmj); \
40 do { \
41 register TYPE t = *pi; \
42 *pi++ = *pj; \
43 *pj++ = t; \
44 } while (--i > 0); \
45 }
46
47 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
48 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
49
50 static __inline void
swapfunc(char * a,char * b,int n,int swaptype)51 swapfunc(char *a, char *b, int n, int swaptype)
52 {
53 if (swaptype <= 1)
54 swapcode(long, a, b, n)
55 else
56 swapcode(char, a, b, n)
57 }
58
59 #define swap(a, b) \
60 if (swaptype == 0) { \
61 long t = *(long *)(a); \
62 *(long *)(a) = *(long *)(b); \
63 *(long *)(b) = t; \
64 } else \
65 swapfunc(a, b, es, swaptype)
66
67 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
68
69 static __inline char *
med3(char * a,char * b,char * c,int (* cmp)(const void *,const void *))70 med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
71 {
72 return cmp(a, b) < 0 ?
73 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
74 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
75 }
76
77 #define min(a,b) (((a) < (b)) ? (a) : (b))
78 void
qsort(void * aa,size_t n,size_t es,int (* cmp)(const void *,const void *))79 qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
80 {
81 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
82 int d, r, swaptype, swap_cnt;
83 register char *a = aa;
84
85 loop: SWAPINIT(a, es);
86 swap_cnt = 0;
87 if (n < 7) {
88 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
89 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
90 pl -= es)
91 swap(pl, pl - es);
92 return;
93 }
94 pm = (char *)a + (n / 2) * es;
95 if (n > 7) {
96 pl = (char *)a;
97 pn = (char *)a + (n - 1) * es;
98 if (n > 40) {
99 d = (n / 8) * es;
100 pl = med3(pl, pl + d, pl + 2 * d, cmp);
101 pm = med3(pm - d, pm, pm + d, cmp);
102 pn = med3(pn - 2 * d, pn - d, pn, cmp);
103 }
104 pm = med3(pl, pm, pn, cmp);
105 }
106 swap(a, pm);
107 pa = pb = (char *)a + es;
108
109 pc = pd = (char *)a + (n - 1) * es;
110 for (;;) {
111 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
112 if (r == 0) {
113 swap_cnt = 1;
114 swap(pa, pb);
115 pa += es;
116 }
117 pb += es;
118 }
119 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
120 if (r == 0) {
121 swap_cnt = 1;
122 swap(pc, pd);
123 pd -= es;
124 }
125 pc -= es;
126 }
127 if (pb > pc)
128 break;
129 swap(pb, pc);
130 swap_cnt = 1;
131 pb += es;
132 pc -= es;
133 }
134 if (swap_cnt == 0) { /* Switch to insertion sort */
135 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
136 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
137 pl -= es)
138 swap(pl, pl - es);
139 return;
140 }
141
142 pn = (char *)a + n * es;
143 r = min(pa - (char *)a, pb - pa);
144 vecswap(a, pb - r, r);
145 r = min((long)(pd - pc), (long)(pn - pd - es));
146 vecswap(pb, pn - r, r);
147 if ((r = pb - pa) > es)
148 qsort(a, r / es, es, cmp);
149 if ((r = pd - pc) > es) {
150 /* Iterate rather than recurse to save stack space */
151 a = pn - r;
152 n = r / es;
153 goto loop;
154 }
155 /* qsort(pn - r, r / es, es, cmp);*/
156 }
157