75fd597d |
1 | /* The following is the NetBSD libc qsort implementation modified in order to |
2 | * support partial sorting of ranges for Redis. |
3 | * |
4 | * Copyright(C) 2009 Salvatore Sanfilippo. All rights reserved. |
5 | * |
6 | * The original copyright notice follows. */ |
7 | |
8 | |
9 | /* $NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $ */ |
10 | |
11 | /*- |
12 | * Copyright (c) 1992, 1993 |
13 | * The Regents of the University of California. All rights reserved. |
14 | * |
15 | * Redistribution and use in source and binary forms, with or without |
16 | * modification, are permitted provided that the following conditions |
17 | * are met: |
18 | * 1. Redistributions of source code must retain the above copyright |
19 | * notice, this list of conditions and the following disclaimer. |
20 | * 2. Redistributions in binary form must reproduce the above copyright |
21 | * notice, this list of conditions and the following disclaimer in the |
22 | * documentation and/or other materials provided with the distribution. |
23 | * 3. Neither the name of the University nor the names of its contributors |
24 | * may be used to endorse or promote products derived from this software |
25 | * without specific prior written permission. |
26 | * |
27 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
28 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
29 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
30 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
31 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
32 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
33 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
34 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
35 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
36 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
37 | * SUCH DAMAGE. |
38 | */ |
39 | |
40 | #include <sys/cdefs.h> |
41 | #if defined(LIBC_SCCS) && !defined(lint) |
42 | #if 0 |
43 | static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93"; |
44 | #else |
45 | __RCSID("$NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $"); |
46 | #endif |
47 | #endif /* LIBC_SCCS and not lint */ |
48 | |
49 | #include <sys/types.h> |
50 | |
51 | #include <assert.h> |
52 | #include <errno.h> |
53 | #include <stdlib.h> |
54 | |
d90b352d |
55 | static inline char *med3 (char *, char *, char *, |
56 | int (*)(const void *, const void *)); |
57 | static inline void swapfunc (char *, char *, size_t, int); |
75fd597d |
58 | |
59 | #define min(a, b) (a) < (b) ? a : b |
60 | |
61 | /* |
62 | * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". |
63 | */ |
64 | #define swapcode(TYPE, parmi, parmj, n) { \ |
65 | size_t i = (n) / sizeof (TYPE); \ |
66 | TYPE *pi = (TYPE *)(void *)(parmi); \ |
67 | TYPE *pj = (TYPE *)(void *)(parmj); \ |
68 | do { \ |
69 | TYPE t = *pi; \ |
70 | *pi++ = *pj; \ |
71 | *pj++ = t; \ |
72 | } while (--i > 0); \ |
73 | } |
74 | |
75 | #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ |
76 | es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; |
77 | |
78 | static inline void |
79 | swapfunc(char *a, char *b, size_t n, int swaptype) |
80 | { |
81 | |
82 | if (swaptype <= 1) |
83 | swapcode(long, a, b, n) |
84 | else |
85 | swapcode(char, a, b, n) |
86 | } |
87 | |
88 | #define swap(a, b) \ |
89 | if (swaptype == 0) { \ |
90 | long t = *(long *)(void *)(a); \ |
91 | *(long *)(void *)(a) = *(long *)(void *)(b); \ |
92 | *(long *)(void *)(b) = t; \ |
93 | } else \ |
94 | swapfunc(a, b, es, swaptype) |
95 | |
96 | #define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype) |
97 | |
98 | static inline char * |
99 | med3(char *a, char *b, char *c, |
d90b352d |
100 | int (*cmp) (const void *, const void *)) |
75fd597d |
101 | { |
102 | |
103 | return cmp(a, b) < 0 ? |
104 | (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) |
105 | :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); |
106 | } |
107 | |
108 | static void |
109 | _pqsort(void *a, size_t n, size_t es, |
d90b352d |
110 | int (*cmp) (const void *, const void *), void *lrange, void *rrange) |
75fd597d |
111 | { |
112 | char *pa, *pb, *pc, *pd, *pl, *pm, *pn; |
113 | size_t d, r; |
114 | int swaptype, swap_cnt, cmp_result; |
115 | |
116 | loop: SWAPINIT(a, es); |
117 | swap_cnt = 0; |
118 | if (n < 7) { |
119 | for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) |
120 | for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; |
121 | pl -= es) |
122 | swap(pl, pl - es); |
123 | return; |
124 | } |
125 | pm = (char *) a + (n / 2) * es; |
126 | if (n > 7) { |
127 | pl = (char *) a; |
128 | pn = (char *) a + (n - 1) * es; |
129 | if (n > 40) { |
130 | d = (n / 8) * es; |
131 | pl = med3(pl, pl + d, pl + 2 * d, cmp); |
132 | pm = med3(pm - d, pm, pm + d, cmp); |
133 | pn = med3(pn - 2 * d, pn - d, pn, cmp); |
134 | } |
135 | pm = med3(pl, pm, pn, cmp); |
136 | } |
137 | swap(a, pm); |
138 | pa = pb = (char *) a + es; |
139 | |
140 | pc = pd = (char *) a + (n - 1) * es; |
141 | for (;;) { |
142 | while (pb <= pc && (cmp_result = cmp(pb, a)) <= 0) { |
143 | if (cmp_result == 0) { |
144 | swap_cnt = 1; |
145 | swap(pa, pb); |
146 | pa += es; |
147 | } |
148 | pb += es; |
149 | } |
150 | while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) { |
151 | if (cmp_result == 0) { |
152 | swap_cnt = 1; |
153 | swap(pc, pd); |
154 | pd -= es; |
155 | } |
156 | pc -= es; |
157 | } |
158 | if (pb > pc) |
159 | break; |
160 | swap(pb, pc); |
161 | swap_cnt = 1; |
162 | pb += es; |
163 | pc -= es; |
164 | } |
165 | if (swap_cnt == 0) { /* Switch to insertion sort */ |
166 | for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) |
167 | for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; |
168 | pl -= es) |
169 | swap(pl, pl - es); |
170 | return; |
171 | } |
172 | |
173 | pn = (char *) a + n * es; |
174 | r = min(pa - (char *) a, pb - pa); |
175 | vecswap(a, pb - r, r); |
176 | r = min((size_t)(pd - pc), pn - pd - es); |
177 | vecswap(pb, pn - r, r); |
178 | if ((r = pb - pa) > es) { |
179 | void *_l = a, *_r = ((unsigned char*)a)+r-1; |
180 | if (!((lrange < _l && rrange < _l) || |
181 | (lrange > _r && rrange > _r))) |
182 | _pqsort(a, r / es, es, cmp, lrange, rrange); |
183 | } |
184 | if ((r = pd - pc) > es) { |
185 | void *_l, *_r; |
186 | |
187 | /* Iterate rather than recurse to save stack space */ |
188 | a = pn - r; |
189 | n = r / es; |
190 | |
191 | _l = a; |
192 | _r = ((unsigned char*)a)+r-1; |
193 | if (!((lrange < _l && rrange < _l) || |
194 | (lrange > _r && rrange > _r))) |
195 | goto loop; |
196 | } |
197 | /* qsort(pn - r, r / es, es, cmp);*/ |
198 | } |
199 | |
200 | void |
201 | pqsort(void *a, size_t n, size_t es, |
d90b352d |
202 | int (*cmp) (const void *, const void *), size_t lrange, size_t rrange) |
75fd597d |
203 | { |
204 | _pqsort(a,n,es,cmp,((unsigned char*)a)+(lrange*es), |
205 | ((unsigned char*)a)+((rrange+1)*es)-1); |
206 | } |