[package] udev: bump to 173
[openwrt.git] / target / linux / generic / files / fs / yaffs2 / yaffs_qsort.c
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
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 *
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 #ifndef min
78 #define min(a,b) (((a) < (b)) ? (a) : (b))
79 #endif
80
81 void
82 yaffs_qsort(void *aa, size_t n, size_t es,
83 int (*cmp)(const void *, const void *))
84 {
85 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
86 int d, r, swaptype, swap_cnt;
87 register char *a = aa;
88
89 loop: SWAPINIT(a, es);
90 swap_cnt = 0;
91 if (n < 7) {
92 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
93 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
94 pl -= es)
95 swap(pl, pl - es);
96 return;
97 }
98 pm = (char *)a + (n / 2) * es;
99 if (n > 7) {
100 pl = (char *)a;
101 pn = (char *)a + (n - 1) * es;
102 if (n > 40) {
103 d = (n / 8) * es;
104 pl = med3(pl, pl + d, pl + 2 * d, cmp);
105 pm = med3(pm - d, pm, pm + d, cmp);
106 pn = med3(pn - 2 * d, pn - d, pn, cmp);
107 }
108 pm = med3(pl, pm, pn, cmp);
109 }
110 swap(a, pm);
111 pa = pb = (char *)a + es;
112
113 pc = pd = (char *)a + (n - 1) * es;
114 for (;;) {
115 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
116 if (r == 0) {
117 swap_cnt = 1;
118 swap(pa, pb);
119 pa += es;
120 }
121 pb += es;
122 }
123 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
124 if (r == 0) {
125 swap_cnt = 1;
126 swap(pc, pd);
127 pd -= es;
128 }
129 pc -= es;
130 }
131 if (pb > pc)
132 break;
133 swap(pb, pc);
134 swap_cnt = 1;
135 pb += es;
136 pc -= es;
137 }
138 if (swap_cnt == 0) { /* Switch to insertion sort */
139 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
140 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
141 pl -= es)
142 swap(pl, pl - es);
143 return;
144 }
145
146 pn = (char *)a + n * es;
147 r = min(pa - (char *)a, pb - pa);
148 vecswap(a, pb - r, r);
149 r = min((long)(pd - pc), (long)(pn - pd - es));
150 vecswap(pb, pn - r, r);
151 if ((r = pb - pa) > es)
152 yaffs_qsort(a, r / es, es, cmp);
153 if ((r = pd - pc) > es) {
154 /* Iterate rather than recurse to save stack space */
155 a = pn - r;
156 n = r / es;
157 goto loop;
158 }
159 /* yaffs_qsort(pn - r, r / es, es, cmp);*/
160 }
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