Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 1 | /* |
| 2 | FUNCTION |
| 3 | <<qsort>>---sort an array |
| 4 | |
| 5 | INDEX |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 6 | qsort |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 7 | |
| 8 | ANSI_SYNOPSIS |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 9 | #include <stdlib.h> |
| 10 | void qsort(void *<[base]>, size_t <[nmemb]>, size_t <[size]>, |
| 11 | int (*<[compar]>)(const void *, const void *) ); |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 12 | |
| 13 | TRAD_SYNOPSIS |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 14 | #include <stdlib.h> |
| 15 | qsort(<[base]>, <[nmemb]>, <[size]>, <[compar]> ) |
| 16 | char *<[base]>; |
| 17 | size_t <[nmemb]>; |
| 18 | size_t <[size]>; |
| 19 | int (*<[compar]>)(); |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 20 | |
| 21 | DESCRIPTION |
| 22 | <<qsort>> sorts an array (beginning at <[base]>) of <[nmemb]> objects. |
| 23 | <[size]> describes the size of each element of the array. |
| 24 | |
| 25 | You must supply a pointer to a comparison function, using the argument |
| 26 | shown as <[compar]>. (This permits sorting objects of unknown |
| 27 | properties.) Define the comparison function to accept two arguments, |
| 28 | each a pointer to an element of the array starting at <[base]>. The |
| 29 | result of <<(*<[compar]>)>> must be negative if the first argument is |
| 30 | less than the second, zero if the two arguments match, and positive if |
| 31 | the first argument is greater than the second (where ``less than'' and |
| 32 | ``greater than'' refer to whatever arbitrary ordering is appropriate). |
| 33 | |
| 34 | The array is sorted in place; that is, when <<qsort>> returns, the |
| 35 | array elements beginning at <[base]> have been reordered. |
| 36 | |
| 37 | RETURNS |
| 38 | <<qsort>> does not return a result. |
| 39 | |
| 40 | PORTABILITY |
| 41 | <<qsort>> is required by ANSI (without specifying the sorting algorithm). |
| 42 | */ |
| 43 | |
| 44 | /*- |
| 45 | * Copyright (c) 1992, 1993 |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 46 | * The Regents of the University of California. All rights reserved. |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 47 | * |
| 48 | * Redistribution and use in source and binary forms, with or without |
| 49 | * modification, are permitted provided that the following conditions |
| 50 | * are met: |
| 51 | * 1. Redistributions of source code must retain the above copyright |
| 52 | * notice, this list of conditions and the following disclaimer. |
| 53 | * 2. Redistributions in binary form must reproduce the above copyright |
| 54 | * notice, this list of conditions and the following disclaimer in the |
| 55 | * documentation and/or other materials provided with the distribution. |
| 56 | * 3. All advertising materials mentioning features or use of this software |
| 57 | * must display the following acknowledgement: |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 58 | * This product includes software developed by the University of |
| 59 | * California, Berkeley and its contributors. |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 60 | * 4. Neither the name of the University nor the names of its contributors |
| 61 | * may be used to endorse or promote products derived from this software |
| 62 | * without specific prior written permission. |
| 63 | * |
| 64 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 65 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 66 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 67 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 68 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 69 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 70 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 71 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 72 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 73 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 74 | * SUCH DAMAGE. |
| 75 | */ |
| 76 | |
| 77 | #include <_ansi.h> |
| 78 | #include <stdlib.h> |
| 79 | |
| 80 | #ifndef __GNUC__ |
| 81 | #define inline |
| 82 | #endif |
| 83 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 84 | static inline char *med3 _PARAMS((char *, char *, char *, int (*cmp)(const _PTR,const _PTR))); |
| 85 | static inline void swapfunc _PARAMS((char *, char *, int, int)); |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 86 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 87 | #define min(a, b) (a) < (b) ? a : b |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 88 | |
| 89 | /* |
| 90 | * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". |
| 91 | */ |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 92 | #define swapcode(TYPE, parmi, parmj, n) { \ |
| 93 | long i = (n) / sizeof (TYPE); \ |
| 94 | register TYPE *pi = (TYPE *) (parmi); \ |
| 95 | register TYPE *pj = (TYPE *) (parmj); \ |
| 96 | do { \ |
| 97 | register TYPE t = *pi; \ |
| 98 | *pi++ = *pj; \ |
| 99 | *pj++ = t; \ |
| 100 | } while (--i > 0); \ |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 101 | } |
| 102 | |
| 103 | #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 104 | es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 105 | |
| 106 | static inline void |
| 107 | _DEFUN(swapfunc, (a, b, n, swaptype), |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 108 | char *a _AND |
| 109 | char *b _AND |
| 110 | int n _AND |
| 111 | int swaptype) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 112 | { |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 113 | if(swaptype <= 1) |
| 114 | swapcode(long, a, b, n) |
| 115 | else |
| 116 | swapcode(char, a, b, n) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 117 | } |
| 118 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 119 | #define swap(a, b) \ |
| 120 | if (swaptype == 0) { \ |
| 121 | long t = *(long *)(a); \ |
| 122 | *(long *)(a) = *(long *)(b); \ |
| 123 | *(long *)(b) = t; \ |
| 124 | } else \ |
| 125 | swapfunc(a, b, es, swaptype) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 126 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 127 | #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 128 | |
| 129 | static inline char * |
| 130 | _DEFUN(med3, (a, b, c, cmp), |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 131 | char *a _AND |
| 132 | char *b _AND |
| 133 | char *c _AND |
| 134 | int (*cmp)(const _PTR,const _PTR)) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 135 | { |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 136 | return cmp(a, b) < 0 ? |
| 137 | (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 138 | :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); |
| 139 | } |
| 140 | |
| 141 | void |
| 142 | _DEFUN(qsort, (a, n, es, cmp), |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 143 | void *a _AND |
| 144 | size_t n _AND |
| 145 | size_t es _AND |
| 146 | int (*cmp)(const _PTR,const _PTR)) |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 147 | { |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 148 | char *pa, *pb, *pc, *pd, *pl, *pm, *pn; |
| 149 | int d, r, swaptype, swap_cnt; |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 150 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 151 | loop: SWAPINIT(a, es); |
| 152 | swap_cnt = 0; |
| 153 | if (n < 7) { |
| 154 | for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) |
| 155 | for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; |
| 156 | pl -= es) |
| 157 | swap(pl, pl - es); |
| 158 | return; |
| 159 | } |
| 160 | pm = (char *) a + (n / 2) * es; |
| 161 | if (n > 7) { |
| 162 | pl = a; |
| 163 | pn = (char *) a + (n - 1) * es; |
| 164 | if (n > 40) { |
| 165 | d = (n / 8) * es; |
| 166 | pl = med3(pl, pl + d, pl + 2 * d, cmp); |
| 167 | pm = med3(pm - d, pm, pm + d, cmp); |
| 168 | pn = med3(pn - 2 * d, pn - d, pn, cmp); |
| 169 | } |
| 170 | pm = med3(pl, pm, pn, cmp); |
| 171 | } |
| 172 | swap(a, pm); |
| 173 | pa = pb = (char *) a + es; |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 174 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 175 | pc = pd = (char *) a + (n - 1) * es; |
| 176 | for (;;) { |
| 177 | while (pb <= pc && (r = cmp(pb, a)) <= 0) { |
| 178 | if (r == 0) { |
| 179 | swap_cnt = 1; |
| 180 | swap(pa, pb); |
| 181 | pa += es; |
| 182 | } |
| 183 | pb += es; |
| 184 | } |
| 185 | while (pb <= pc && (r = cmp(pc, a)) >= 0) { |
| 186 | if (r == 0) { |
| 187 | swap_cnt = 1; |
| 188 | swap(pc, pd); |
| 189 | pd -= es; |
| 190 | } |
| 191 | pc -= es; |
| 192 | } |
| 193 | if (pb > pc) |
| 194 | break; |
| 195 | swap(pb, pc); |
| 196 | swap_cnt = 1; |
| 197 | pb += es; |
| 198 | pc -= es; |
| 199 | } |
| 200 | if (swap_cnt == 0) { /* Switch to insertion sort */ |
| 201 | for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) |
| 202 | for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; |
| 203 | pl -= es) |
| 204 | swap(pl, pl - es); |
| 205 | return; |
| 206 | } |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 207 | |
Andree Buschmann | 0b7dcd6 | 2010-02-22 21:24:09 +0000 | [diff] [blame] | 208 | pn = (char *) a + n * es; |
| 209 | r = min(pa - (char *)a, pb - pa); |
| 210 | vecswap(a, pb - r, r); |
| 211 | r = min((unsigned int)(pd - pc), pn - pd - es); |
| 212 | vecswap(pb, pn - r, r); |
| 213 | if ((unsigned int)(r = pb - pa) > es) |
| 214 | qsort(a, r / es, es, cmp); |
| 215 | if ((unsigned int)(r = pd - pc) > es) { |
| 216 | /* Iterate rather than recurse to save stack space */ |
| 217 | a = pn - r; |
| 218 | n = r / es; |
| 219 | goto loop; |
| 220 | } |
| 221 | /* qsort(pn - r, r / es, es, cmp);*/ |
Björn Stenberg | b69338f | 2002-05-30 21:03:17 +0000 | [diff] [blame] | 222 | } |