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 } 164