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comparison packages/fs/yaffs/current/src/yaffs_qsort.c @ 425:dea4d7d250ad ecos

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Move sources into packages/fs/yaffs/current/src/
author Ross Younger <wry@ecoscentric.com>
date Fri, 14 May 2010 16:03:09 +0100
parents yaffs_qsort.c@c0dfae9e8073
children
comparison
equal deleted inserted replaced
424:d21d6fd33e63 425:dea4d7d250ad
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) do { \
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 } while (0)
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
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 yswap(a, b) do { \
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 } while (0)
67
68 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
69
70 static __inline char *
71 med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
72 {
73 return cmp(a, b) < 0 ?
74 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a))
75 : (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c));
76 }
77
78 #ifndef min
79 #define min(a, b) (((a) < (b)) ? (a) : (b))
80 #endif
81
82 void
83 yaffs_qsort(void *aa, size_t n, size_t es,
84 int (*cmp)(const void *, const void *))
85 {
86 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
87 int d, r, swaptype, swap_cnt;
88 register char *a = aa;
89
90 loop: SWAPINIT(a, es);
91 swap_cnt = 0;
92 if (n < 7) {
93 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
94 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
95 pl -= es)
96 yswap(pl, pl - es);
97 return;
98 }
99 pm = (char *)a + (n / 2) * es;
100 if (n > 7) {
101 pl = (char *)a;
102 pn = (char *)a + (n - 1) * es;
103 if (n > 40) {
104 d = (n / 8) * es;
105 pl = med3(pl, pl + d, pl + 2 * d, cmp);
106 pm = med3(pm - d, pm, pm + d, cmp);
107 pn = med3(pn - 2 * d, pn - d, pn, cmp);
108 }
109 pm = med3(pl, pm, pn, cmp);
110 }
111 yswap(a, pm);
112 pa = pb = (char *)a + es;
113
114 pc = pd = (char *)a + (n - 1) * es;
115 for (;;) {
116 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
117 if (r == 0) {
118 swap_cnt = 1;
119 yswap(pa, pb);
120 pa += es;
121 }
122 pb += es;
123 }
124 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
125 if (r == 0) {
126 swap_cnt = 1;
127 yswap(pc, pd);
128 pd -= es;
129 }
130 pc -= es;
131 }
132 if (pb > pc)
133 break;
134 yswap(pb, pc);
135 swap_cnt = 1;
136 pb += es;
137 pc -= es;
138 }
139 if (swap_cnt == 0) { /* Switch to insertion sort */
140 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
141 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
142 pl -= es)
143 yswap(pl, pl - es);
144 return;
145 }
146
147 pn = (char *)a + n * es;
148 r = min(pa - (char *)a, pb - pa);
149 vecswap(a, pb - r, r);
150 r = min((long)(pd - pc), (long)(pn - pd - es));
151 vecswap(pb, pn - r, r);
152 r = pb - pa;
153 if (r > es)
154 yaffs_qsort(a, r / es, es, cmp);
155 r = pd - pc;
156 if (r > es) {
157 /* Iterate rather than recurse to save stack space */
158 a = pn - r;
159 n = r / es;
160 goto loop;
161 }
162 /* yaffs_qsort(pn - r, r / es, es, cmp);*/
163 }