Mercurial > yaffs-ecoscentric-gpl
annotate yaffs_qsort.c @ 389:10fe81fa4682
Update yaffs docs
| author | charles <charles> |
|---|---|
| date | Tue, 16 Mar 2010 03:30:45 +0000 |
| parents | c0dfae9e8073 |
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| rev | line source |
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| 130 | 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" | |
|
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31 /* #include <linux/string.h> */ |
| 130 | 32 |
| 33 /* | |
| 34 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". | |
| 35 */ | |
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36 #define swapcode(TYPE, parmi, parmj, n) do { \ |
| 130 | 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; \ | |
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44 } while (--i > 0); \ |
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45 } while (0) |
| 130 | 46 |
| 47 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ | |
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48 es % sizeof(long) ? 2 : es == sizeof(long) ? 0 : 1; |
| 130 | 49 |
| 50 static __inline void | |
| 51 swapfunc(char *a, char *b, int n, int swaptype) | |
| 52 { | |
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53 if (swaptype <= 1) |
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54 swapcode(long, a, b, n); |
| 130 | 55 else |
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56 swapcode(char, a, b, n); |
| 130 | 57 } |
| 58 | |
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59 #define yswap(a, b) do { \ |
| 130 | 60 if (swaptype == 0) { \ |
| 61 long t = *(long *)(a); \ | |
| 62 *(long *)(a) = *(long *)(b); \ | |
| 63 *(long *)(b) = t; \ | |
| 64 } else \ | |
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65 swapfunc(a, b, es, swaptype); \ |
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66 } while (0) |
| 130 | 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 ? | |
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74 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a)) |
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75 : (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c)); |
| 130 | 76 } |
| 77 | |
| 179 | 78 #ifndef min |
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79 #define min(a, b) (((a) < (b)) ? (a) : (b)) |
| 179 | 80 #endif |
| 81 | |
| 130 | 82 void |
| 179 | 83 yaffs_qsort(void *aa, size_t n, size_t es, |
| 84 int (*cmp)(const void *, const void *)) | |
| 130 | 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) | |
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96 yswap(pl, pl - es); |
| 130 | 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 } | |
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111 yswap(a, pm); |
| 130 | 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; | |
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119 yswap(pa, pb); |
| 130 | 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; | |
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127 yswap(pc, pd); |
| 130 | 128 pd -= es; |
| 129 } | |
| 130 pc -= es; | |
| 131 } | |
| 132 if (pb > pc) | |
| 133 break; | |
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134 yswap(pb, pc); |
| 130 | 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) | |
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141 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; |
| 130 | 142 pl -= es) |
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143 yswap(pl, pl - es); |
| 130 | 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); | |
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152 r = pb - pa; |
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153 if (r > es) |
| 179 | 154 yaffs_qsort(a, r / es, es, cmp); |
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155 r = pd - pc; |
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156 if (r > es) { |
| 130 | 157 /* Iterate rather than recurse to save stack space */ |
| 158 a = pn - r; | |
| 159 n = r / es; | |
| 160 goto loop; | |
| 161 } | |
| 179 | 162 /* yaffs_qsort(pn - r, r / es, es, cmp);*/ |
| 130 | 163 } |