| 1 | /* |
|---|
| 2 | FUNCTION |
|---|
| 3 | <<qsort>>---sort an array |
|---|
| 4 | |
|---|
| 5 | INDEX |
|---|
| 6 | qsort |
|---|
| 7 | |
|---|
| 8 | SYNOPSIS |
|---|
| 9 | #include <stdlib.h> |
|---|
| 10 | void qsort(void *<[base]>, size_t <[nmemb]>, size_t <[size]>, |
|---|
| 11 | int (*<[compar]>)(const void *, const void *) ); |
|---|
| 12 | |
|---|
| 13 | DESCRIPTION |
|---|
| 14 | <<qsort>> sorts an array (beginning at <[base]>) of <[nmemb]> objects. |
|---|
| 15 | <[size]> describes the size of each element of the array. |
|---|
| 16 | |
|---|
| 17 | You must supply a pointer to a comparison function, using the argument |
|---|
| 18 | shown as <[compar]>. (This permits sorting objects of unknown |
|---|
| 19 | properties.) Define the comparison function to accept two arguments, |
|---|
| 20 | each a pointer to an element of the array starting at <[base]>. The |
|---|
| 21 | result of <<(*<[compar]>)>> must be negative if the first argument is |
|---|
| 22 | less than the second, zero if the two arguments match, and positive if |
|---|
| 23 | the first argument is greater than the second (where ``less than'' and |
|---|
| 24 | ``greater than'' refer to whatever arbitrary ordering is appropriate). |
|---|
| 25 | |
|---|
| 26 | The array is sorted in place; that is, when <<qsort>> returns, the |
|---|
| 27 | array elements beginning at <[base]> have been reordered. |
|---|
| 28 | |
|---|
| 29 | RETURNS |
|---|
| 30 | <<qsort>> does not return a result. |
|---|
| 31 | |
|---|
| 32 | PORTABILITY |
|---|
| 33 | <<qsort>> is required by ANSI (without specifying the sorting algorithm). |
|---|
| 34 | */ |
|---|
| 35 | |
|---|
| 36 | /*- |
|---|
| 37 | * Copyright (c) 1992, 1993 |
|---|
| 38 | * The Regents of the University of California. All rights reserved. |
|---|
| 39 | * |
|---|
| 40 | * Redistribution and use in source and binary forms, with or without |
|---|
| 41 | * modification, are permitted provided that the following conditions |
|---|
| 42 | * are met: |
|---|
| 43 | * 1. Redistributions of source code must retain the above copyright |
|---|
| 44 | * notice, this list of conditions and the following disclaimer. |
|---|
| 45 | * 2. Redistributions in binary form must reproduce the above copyright |
|---|
| 46 | * notice, this list of conditions and the following disclaimer in the |
|---|
| 47 | * documentation and/or other materials provided with the distribution. |
|---|
| 48 | * 3. Neither the name of the University nor the names of its contributors |
|---|
| 49 | * may be used to endorse or promote products derived from this software |
|---|
| 50 | * without specific prior written permission. |
|---|
| 51 | * |
|---|
| 52 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
|---|
| 53 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
|---|
| 54 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
|---|
| 55 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
|---|
| 56 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
|---|
| 57 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
|---|
| 58 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
|---|
| 59 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
|---|
| 60 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
|---|
| 61 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
|---|
| 62 | * SUCH DAMAGE. |
|---|
| 63 | */ |
|---|
| 64 | |
|---|
| 65 | #include <_ansi.h> |
|---|
| 66 | #include <sys/cdefs.h> |
|---|
| 67 | #include <stdlib.h> |
|---|
| 68 | |
|---|
| 69 | #ifndef __GNUC__ |
|---|
| 70 | #define inline |
|---|
| 71 | #endif |
|---|
| 72 | |
|---|
| 73 | #if defined(I_AM_QSORT_R) |
|---|
| 74 | typedef int cmp_t(void *, const void *, const void *); |
|---|
| 75 | #elif defined(I_AM_GNU_QSORT_R) |
|---|
| 76 | typedef int cmp_t(const void *, const void *, void *); |
|---|
| 77 | #else |
|---|
| 78 | typedef int cmp_t(const void *, const void *); |
|---|
| 79 | #endif |
|---|
| 80 | static inline char *med3 (char *, char *, char *, cmp_t *, void *); |
|---|
| 81 | static inline void swapfunc (char *, char *, int, int); |
|---|
| 82 | |
|---|
| 83 | #define min(a, b) (a) < (b) ? a : b |
|---|
| 84 | |
|---|
| 85 | /* |
|---|
| 86 | * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". |
|---|
| 87 | */ |
|---|
| 88 | #define swapcode(TYPE, parmi, parmj, n) { \ |
|---|
| 89 | long i = (n) / sizeof (TYPE); \ |
|---|
| 90 | TYPE *pi = (TYPE *) (parmi); \ |
|---|
| 91 | TYPE *pj = (TYPE *) (parmj); \ |
|---|
| 92 | do { \ |
|---|
| 93 | TYPE t = *pi; \ |
|---|
| 94 | *pi++ = *pj; \ |
|---|
| 95 | *pj++ = t; \ |
|---|
| 96 | } while (--i > 0); \ |
|---|
| 97 | } |
|---|
| 98 | |
|---|
| 99 | #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ |
|---|
| 100 | es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; |
|---|
| 101 | |
|---|
| 102 | static inline void |
|---|
| 103 | swapfunc (char *a, |
|---|
| 104 | char *b, |
|---|
| 105 | int n, |
|---|
| 106 | int swaptype) |
|---|
| 107 | { |
|---|
| 108 | if(swaptype <= 1) |
|---|
| 109 | swapcode(long, a, b, n) |
|---|
| 110 | else |
|---|
| 111 | swapcode(char, a, b, n) |
|---|
| 112 | } |
|---|
| 113 | |
|---|
| 114 | #define swap(a, b) \ |
|---|
| 115 | if (swaptype == 0) { \ |
|---|
| 116 | long t = *(long *)(a); \ |
|---|
| 117 | *(long *)(a) = *(long *)(b); \ |
|---|
| 118 | *(long *)(b) = t; \ |
|---|
| 119 | } else \ |
|---|
| 120 | swapfunc(a, b, es, swaptype) |
|---|
| 121 | |
|---|
| 122 | #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) |
|---|
| 123 | |
|---|
| 124 | #if defined(I_AM_QSORT_R) |
|---|
| 125 | #define CMP(t, x, y) (cmp((t), (x), (y))) |
|---|
| 126 | #elif defined(I_AM_GNU_QSORT_R) |
|---|
| 127 | #define CMP(t, x, y) (cmp((x), (y), (t))) |
|---|
| 128 | #else |
|---|
| 129 | #define CMP(t, x, y) (cmp((x), (y))) |
|---|
| 130 | #endif |
|---|
| 131 | |
|---|
| 132 | static inline char * |
|---|
| 133 | med3 (char *a, |
|---|
| 134 | char *b, |
|---|
| 135 | char *c, |
|---|
| 136 | cmp_t *cmp, |
|---|
| 137 | void *thunk |
|---|
| 138 | #if !defined(I_AM_QSORT_R) && !defined(I_AM_GNU_QSORT_R) |
|---|
| 139 | __unused |
|---|
| 140 | #endif |
|---|
| 141 | ) |
|---|
| 142 | { |
|---|
| 143 | return CMP(thunk, a, b) < 0 ? |
|---|
| 144 | (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a )) |
|---|
| 145 | :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c )); |
|---|
| 146 | } |
|---|
| 147 | |
|---|
| 148 | #if defined(I_AM_QSORT_R) |
|---|
| 149 | void |
|---|
| 150 | __bsd_qsort_r (void *a, |
|---|
| 151 | size_t n, |
|---|
| 152 | size_t es, |
|---|
| 153 | void *thunk, |
|---|
| 154 | cmp_t *cmp) |
|---|
| 155 | #elif defined(I_AM_GNU_QSORT_R) |
|---|
| 156 | void |
|---|
| 157 | qsort_r (void *a, |
|---|
| 158 | size_t n, |
|---|
| 159 | size_t es, |
|---|
| 160 | cmp_t *cmp, |
|---|
| 161 | void *thunk) |
|---|
| 162 | #else |
|---|
| 163 | #define thunk NULL |
|---|
| 164 | void |
|---|
| 165 | qsort (void *a, |
|---|
| 166 | size_t n, |
|---|
| 167 | size_t es, |
|---|
| 168 | cmp_t *cmp) |
|---|
| 169 | #endif |
|---|
| 170 | { |
|---|
| 171 | char *pa, *pb, *pc, *pd, *pl, *pm, *pn; |
|---|
| 172 | size_t d, r; |
|---|
| 173 | int cmp_result; |
|---|
| 174 | int swaptype, swap_cnt; |
|---|
| 175 | |
|---|
| 176 | loop: SWAPINIT(a, es); |
|---|
| 177 | swap_cnt = 0; |
|---|
| 178 | if (n < 7) { |
|---|
| 179 | for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) |
|---|
| 180 | for (pl = pm; pl > (char *) a && CMP(thunk, pl - es, pl) > 0; |
|---|
| 181 | pl -= es) |
|---|
| 182 | swap(pl, pl - es); |
|---|
| 183 | return; |
|---|
| 184 | } |
|---|
| 185 | pm = (char *) a + (n / 2) * es; |
|---|
| 186 | if (n > 7) { |
|---|
| 187 | pl = a; |
|---|
| 188 | pn = (char *) a + (n - 1) * es; |
|---|
| 189 | if (n > 40) { |
|---|
| 190 | d = (n / 8) * es; |
|---|
| 191 | pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); |
|---|
| 192 | pm = med3(pm - d, pm, pm + d, cmp, thunk); |
|---|
| 193 | pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); |
|---|
| 194 | } |
|---|
| 195 | pm = med3(pl, pm, pn, cmp, thunk); |
|---|
| 196 | } |
|---|
| 197 | swap(a, pm); |
|---|
| 198 | pa = pb = (char *) a + es; |
|---|
| 199 | |
|---|
| 200 | pc = pd = (char *) a + (n - 1) * es; |
|---|
| 201 | for (;;) { |
|---|
| 202 | while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { |
|---|
| 203 | if (cmp_result == 0) { |
|---|
| 204 | swap_cnt = 1; |
|---|
| 205 | swap(pa, pb); |
|---|
| 206 | pa += es; |
|---|
| 207 | } |
|---|
| 208 | pb += es; |
|---|
| 209 | } |
|---|
| 210 | while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { |
|---|
| 211 | if (cmp_result == 0) { |
|---|
| 212 | swap_cnt = 1; |
|---|
| 213 | swap(pc, pd); |
|---|
| 214 | pd -= es; |
|---|
| 215 | } |
|---|
| 216 | pc -= es; |
|---|
| 217 | } |
|---|
| 218 | if (pb > pc) |
|---|
| 219 | break; |
|---|
| 220 | swap(pb, pc); |
|---|
| 221 | swap_cnt = 1; |
|---|
| 222 | pb += es; |
|---|
| 223 | pc -= es; |
|---|
| 224 | } |
|---|
| 225 | if (swap_cnt == 0) { /* Switch to insertion sort */ |
|---|
| 226 | for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) |
|---|
| 227 | for (pl = pm; pl > (char *) a && CMP(thunk, pl - es, pl) > 0; |
|---|
| 228 | pl -= es) |
|---|
| 229 | swap(pl, pl - es); |
|---|
| 230 | return; |
|---|
| 231 | } |
|---|
| 232 | |
|---|
| 233 | pn = (char *) a + n * es; |
|---|
| 234 | r = min(pa - (char *)a, pb - pa); |
|---|
| 235 | vecswap(a, pb - r, r); |
|---|
| 236 | r = min(pd - pc, pn - pd - es); |
|---|
| 237 | vecswap(pb, pn - r, r); |
|---|
| 238 | if ((r = pb - pa) > es) |
|---|
| 239 | #if defined(I_AM_QSORT_R) |
|---|
| 240 | __bsd_qsort_r(a, r / es, es, thunk, cmp); |
|---|
| 241 | #elif defined(I_AM_GNU_QSORT_R) |
|---|
| 242 | qsort_r(a, r / es, es, cmp, thunk); |
|---|
| 243 | #else |
|---|
| 244 | qsort(a, r / es, es, cmp); |
|---|
| 245 | #endif |
|---|
| 246 | if ((r = pd - pc) > es) { |
|---|
| 247 | /* Iterate rather than recurse to save stack space */ |
|---|
| 248 | a = pn - r; |
|---|
| 249 | n = r / es; |
|---|
| 250 | goto loop; |
|---|
| 251 | } |
|---|
| 252 | /* qsort(pn - r, r / es, es, cmp);*/ |
|---|
| 253 | } |
|---|
