1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/param.h>
33 #include <sys/libkern.h>
34
35 #ifdef I_AM_QSORT_R
36 typedef int cmp_t(const void *, const void *, void *);
37 #else
38 typedef int cmp_t(const void *, const void *);
39 #endif
40 static inline char *med3(char *, char *, char *, cmp_t *, void *);
41 static inline void swapfunc(char *, char *, size_t, int, int);
42
43 /*
44 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
45 */
46 #define swapcode(TYPE, parmi, parmj, n) { \
47 size_t i = (n) / sizeof (TYPE); \
48 TYPE *pi = (TYPE *) (parmi); \
49 TYPE *pj = (TYPE *) (parmj); \
50 do { \
51 TYPE t = *pi; \
52 *pi++ = *pj; \
53 *pj++ = t; \
54 } while (--i > 0); \
55 }
56
57 #define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \
58 ((char *)a - (char *)0) % sizeof(TYPE) || \
59 es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1;
60
61 static inline void
swapfunc(char * a,char * b,size_t n,int swaptype_long,int swaptype_int)62 swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int)
63 {
64 if (swaptype_long <= 1)
65 swapcode(long, a, b, n)
66 else if (swaptype_int <= 1)
67 swapcode(int, a, b, n)
68 else
69 swapcode(char, a, b, n)
70 }
71
72 #define swap(a, b) \
73 if (swaptype_long == 0) { \
74 long t = *(long *)(a); \
75 *(long *)(a) = *(long *)(b); \
76 *(long *)(b) = t; \
77 } else if (swaptype_int == 0) { \
78 int t = *(int *)(a); \
79 *(int *)(a) = *(int *)(b); \
80 *(int *)(b) = t; \
81 } else \
82 swapfunc(a, b, es, swaptype_long, swaptype_int)
83
84 #define vecswap(a, b, n) \
85 if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int)
86
87 #ifdef I_AM_QSORT_R
88 #define CMP(t, x, y) (cmp((x), (y), (t)))
89 #else
90 #define CMP(t, x, y) (cmp((x), (y)))
91 #endif
92
93 static inline char *
med3(char * a,char * b,char * c,cmp_t * cmp,void * thunk __unused)94 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
95 #ifndef I_AM_QSORT_R
96 __unused
97 #endif
98 )
99 {
100 return CMP(thunk, a, b) < 0 ?
101 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
102 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
103 }
104
105 #ifdef I_AM_QSORT_R
106 void
107 (qsort_r)(void *a, size_t n, size_t es, cmp_t *cmp, void *thunk)
108 #else
109 #define thunk NULL
110 void
111 qsort(void *a, size_t n, size_t es, cmp_t *cmp)
112 #endif
113 {
114 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
115 size_t d1, d2;
116 int cmp_result;
117 int swaptype_long, swaptype_int, swap_cnt;
118
119 loop: SWAPINIT(long, a, es);
120 SWAPINIT(int, a, es);
121 swap_cnt = 0;
122 if (n < 7) {
123 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
124 for (pl = pm;
125 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
126 pl -= es)
127 swap(pl, pl - es);
128 return;
129 }
130 pm = (char *)a + (n / 2) * es;
131 if (n > 7) {
132 pl = a;
133 pn = (char *)a + (n - 1) * es;
134 if (n > 40) {
135 size_t d = (n / 8) * es;
136
137 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
138 pm = med3(pm - d, pm, pm + d, cmp, thunk);
139 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
140 }
141 pm = med3(pl, pm, pn, cmp, thunk);
142 }
143 swap(a, pm);
144 pa = pb = (char *)a + es;
145
146 pc = pd = (char *)a + (n - 1) * es;
147 for (;;) {
148 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
149 if (cmp_result == 0) {
150 swap_cnt = 1;
151 swap(pa, pb);
152 pa += es;
153 }
154 pb += es;
155 }
156 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
157 if (cmp_result == 0) {
158 swap_cnt = 1;
159 swap(pc, pd);
160 pd -= es;
161 }
162 pc -= es;
163 }
164 if (pb > pc)
165 break;
166 swap(pb, pc);
167 swap_cnt = 1;
168 pb += es;
169 pc -= es;
170 }
171 if (swap_cnt == 0) { /* Switch to insertion sort */
172 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
173 for (pl = pm;
174 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
175 pl -= es)
176 swap(pl, pl - es);
177 return;
178 }
179
180 pn = (char *)a + n * es;
181 d1 = MIN(pa - (char *)a, pb - pa);
182 vecswap(a, pb - d1, d1);
183 d1 = MIN(pd - pc, pn - pd - es);
184 vecswap(pb, pn - d1, d1);
185
186 d1 = pb - pa;
187 d2 = pd - pc;
188 if (d1 <= d2) {
189 /* Recurse on left partition, then iterate on right partition */
190 if (d1 > es) {
191 #ifdef I_AM_QSORT_R
192 qsort_r(a, d1 / es, es, cmp, thunk);
193 #else
194 qsort(a, d1 / es, es, cmp);
195 #endif
196 }
197 if (d2 > es) {
198 /* Iterate rather than recurse to save stack space */
199 /* qsort(pn - d2, d2 / es, es, cmp); */
200 a = pn - d2;
201 n = d2 / es;
202 goto loop;
203 }
204 } else {
205 /* Recurse on right partition, then iterate on left partition */
206 if (d2 > es) {
207 #ifdef I_AM_QSORT_R
208 qsort_r(pn - d2, d2 / es, es, cmp, thunk);
209 #else
210 qsort(pn - d2, d2 / es, es, cmp);
211 #endif
212 }
213 if (d1 > es) {
214 /* Iterate rather than recurse to save stack space */
215 /* qsort(a, d1 / es, es, cmp); */
216 n = d1 / es;
217 goto loop;
218 }
219 }
220 }
221