xref: /openbmc/u-boot/fs/yaffs2/yaffs_qsort.c (revision e89516f0)
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 /* XXX U-BOOT XXX */
31 #include <common.h>
32 
33 #include "yportenv.h"
34 //#include <linux/string.h>
35 
36 /*
37  * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
38  */
39 #define swapcode(TYPE, parmi, parmj, n) { 		\
40 	long i = (n) / sizeof (TYPE); 			\
41 	register TYPE *pi = (TYPE *) (parmi); 		\
42 	register TYPE *pj = (TYPE *) (parmj); 		\
43 	do { 						\
44 		register TYPE	t = *pi;		\
45 		*pi++ = *pj;				\
46 		*pj++ = t;				\
47 	} while (--i > 0);				\
48 }
49 
50 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
51 	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
52 
53 static __inline void
54 swapfunc(char *a, char *b, int n, int swaptype)
55 {
56 	if (swaptype <= 1)
57 		swapcode(long, a, b, n)
58 	else
59 		swapcode(char, a, b, n)
60 }
61 
62 #define swap(a, b)					\
63 	if (swaptype == 0) {				\
64 		long t = *(long *)(a);			\
65 		*(long *)(a) = *(long *)(b);		\
66 		*(long *)(b) = t;			\
67 	} else						\
68 		swapfunc(a, b, es, swaptype)
69 
70 #define vecswap(a, b, n) 	if ((n) > 0) swapfunc(a, b, n, swaptype)
71 
72 static __inline char *
73 med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
74 {
75 	return cmp(a, b) < 0 ?
76 	       (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
77 	      :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
78 }
79 
80 #ifndef min
81 #define min(a,b) (((a) < (b)) ? (a) : (b))
82 #endif
83 
84 void
85 yaffs_qsort(void *aa, size_t n, size_t es,
86 	int (*cmp)(const void *, const void *))
87 {
88 	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
89 	int d, r, swaptype, swap_cnt;
90 	register char *a = aa;
91 
92 loop:	SWAPINIT(a, es);
93 	swap_cnt = 0;
94 	if (n < 7) {
95 		for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
96 			for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
97 			     pl -= es)
98 				swap(pl, pl - es);
99 		return;
100 	}
101 	pm = (char *)a + (n / 2) * es;
102 	if (n > 7) {
103 		pl = (char *)a;
104 		pn = (char *)a + (n - 1) * es;
105 		if (n > 40) {
106 			d = (n / 8) * es;
107 			pl = med3(pl, pl + d, pl + 2 * d, cmp);
108 			pm = med3(pm - d, pm, pm + d, cmp);
109 			pn = med3(pn - 2 * d, pn - d, pn, cmp);
110 		}
111 		pm = med3(pl, pm, pn, cmp);
112 	}
113 	swap(a, pm);
114 	pa = pb = (char *)a + es;
115 
116 	pc = pd = (char *)a + (n - 1) * es;
117 	for (;;) {
118 		while (pb <= pc && (r = cmp(pb, a)) <= 0) {
119 			if (r == 0) {
120 				swap_cnt = 1;
121 				swap(pa, pb);
122 				pa += es;
123 			}
124 			pb += es;
125 		}
126 		while (pb <= pc && (r = cmp(pc, a)) >= 0) {
127 			if (r == 0) {
128 				swap_cnt = 1;
129 				swap(pc, pd);
130 				pd -= es;
131 			}
132 			pc -= es;
133 		}
134 		if (pb > pc)
135 			break;
136 		swap(pb, pc);
137 		swap_cnt = 1;
138 		pb += es;
139 		pc -= es;
140 	}
141 	if (swap_cnt == 0) {  /* Switch to insertion sort */
142 		for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
143 			for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
144 			     pl -= es)
145 				swap(pl, pl - es);
146 		return;
147 	}
148 
149 	pn = (char *)a + n * es;
150 	r = min(pa - (char *)a, pb - pa);
151 	vecswap(a, pb - r, r);
152 	r = min((long)(pd - pc), (long)(pn - pd - es));
153 	vecswap(pb, pn - r, r);
154 	if ((r = pb - pa) > es)
155 		yaffs_qsort(a, r / es, es, cmp);
156 	if ((r = pd - pc) > 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 }
164