1 // SPDX-License-Identifier: BSD-3-Clause 2 /* 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 */ 6 7 #include "yportenv.h" 8 /* #include <linux/string.h> */ 9 10 /* 11 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 12 */ 13 #define swapcode(TYPE, parmi, parmj, n) do { \ 14 long i = (n) / sizeof(TYPE); \ 15 register TYPE *pi = (TYPE *) (parmi); \ 16 register TYPE *pj = (TYPE *) (parmj); \ 17 do { \ 18 register TYPE t = *pi; \ 19 *pi++ = *pj; \ 20 *pj++ = t; \ 21 } while (--i > 0); \ 22 } while (0) 23 24 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 25 es % sizeof(long) ? 2 : es == sizeof(long) ? 0 : 1; 26 27 static inline void 28 swapfunc(char *a, char *b, int n, int swaptype) 29 { 30 if (swaptype <= 1) 31 swapcode(long, a, b, n); 32 else 33 swapcode(char, a, b, n); 34 } 35 36 #define yswap(a, b) do { \ 37 if (swaptype == 0) { \ 38 long t = *(long *)(a); \ 39 *(long *)(a) = *(long *)(b); \ 40 *(long *)(b) = t; \ 41 } else \ 42 swapfunc(a, b, es, swaptype); \ 43 } while (0) 44 45 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 46 47 static inline char * 48 med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *)) 49 { 50 return cmp(a, b) < 0 ? 51 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a)) 52 : (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c)); 53 } 54 55 #ifndef min 56 #define min(a, b) (((a) < (b)) ? (a) : (b)) 57 #endif 58 59 void 60 yaffs_qsort(void *aa, size_t n, size_t es, 61 int (*cmp)(const void *, const void *)) 62 { 63 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 64 int d, r, swaptype, swap_cnt; 65 register char *a = aa; 66 67 loop: SWAPINIT(a, es); 68 swap_cnt = 0; 69 if (n < 7) { 70 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es) 71 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; 72 pl -= es) 73 yswap(pl, pl - es); 74 return; 75 } 76 pm = (char *)a + (n / 2) * es; 77 if (n > 7) { 78 pl = (char *)a; 79 pn = (char *)a + (n - 1) * es; 80 if (n > 40) { 81 d = (n / 8) * es; 82 pl = med3(pl, pl + d, pl + 2 * d, cmp); 83 pm = med3(pm - d, pm, pm + d, cmp); 84 pn = med3(pn - 2 * d, pn - d, pn, cmp); 85 } 86 pm = med3(pl, pm, pn, cmp); 87 } 88 yswap(a, pm); 89 pa = pb = (char *)a + es; 90 91 pc = pd = (char *)a + (n - 1) * es; 92 for (;;) { 93 while (pb <= pc && (r = cmp(pb, a)) <= 0) { 94 if (r == 0) { 95 swap_cnt = 1; 96 yswap(pa, pb); 97 pa += es; 98 } 99 pb += es; 100 } 101 while (pb <= pc && (r = cmp(pc, a)) >= 0) { 102 if (r == 0) { 103 swap_cnt = 1; 104 yswap(pc, pd); 105 pd -= es; 106 } 107 pc -= es; 108 } 109 if (pb > pc) 110 break; 111 yswap(pb, pc); 112 swap_cnt = 1; 113 pb += es; 114 pc -= es; 115 } 116 if (swap_cnt == 0) { /* Switch to insertion sort */ 117 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) 118 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; 119 pl -= es) 120 yswap(pl, pl - es); 121 return; 122 } 123 124 pn = (char *)a + n * es; 125 r = min(pa - (char *)a, pb - pa); 126 vecswap(a, pb - r, r); 127 r = min((long)(pd - pc), (long)(pn - pd - es)); 128 vecswap(pb, pn - r, r); 129 r = pb - pa; 130 if (r > es) 131 yaffs_qsort(a, r / es, es, cmp); 132 r = pd - pc; 133 if (r > es) { 134 /* Iterate rather than recurse to save stack space */ 135 a = pn - r; 136 n = r / es; 137 goto loop; 138 } 139 /* yaffs_qsort(pn - r, r / es, es, cmp);*/ 140 } 141