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75fd597 @antirez psort.c/h added. This is a partial qsort implementation that Redis wi…
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1 /* The following is the NetBSD libc qsort implementation modified in order to
2 * support partial sorting of ranges for Redis.
3 *
12d090d @antirez A problem with replication with multiple slaves connectiong to a sing…
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4 * Copyright(C) 2009-2010 Salvatore Sanfilippo. All rights reserved.
75fd597 @antirez psort.c/h added. This is a partial qsort implementation that Redis wi…
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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/types.h>
41
42 #include <assert.h>
43 #include <errno.h>
44 #include <stdlib.h>
45
d90b352 @antirez __P completely removed from pqsort.c/h
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46 static inline char *med3 (char *, char *, char *,
47 int (*)(const void *, const void *));
48 static inline void swapfunc (char *, char *, size_t, int);
75fd597 @antirez psort.c/h added. This is a partial qsort implementation that Redis wi…
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49
50 #define min(a, b) (a) < (b) ? a : b
51
52 /*
53 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
54 */
55 #define swapcode(TYPE, parmi, parmj, n) { \
56 size_t i = (n) / sizeof (TYPE); \
57 TYPE *pi = (TYPE *)(void *)(parmi); \
58 TYPE *pj = (TYPE *)(void *)(parmj); \
59 do { \
60 TYPE t = *pi; \
61 *pi++ = *pj; \
62 *pj++ = t; \
63 } while (--i > 0); \
64 }
65
66 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
67 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
68
69 static inline void
70 swapfunc(char *a, char *b, size_t n, int swaptype)
71 {
72
73 if (swaptype <= 1)
74 swapcode(long, a, b, n)
75 else
76 swapcode(char, a, b, n)
77 }
78
79 #define swap(a, b) \
80 if (swaptype == 0) { \
81 long t = *(long *)(void *)(a); \
82 *(long *)(void *)(a) = *(long *)(void *)(b); \
83 *(long *)(void *)(b) = t; \
84 } else \
85 swapfunc(a, b, es, swaptype)
86
87 #define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
88
89 static inline char *
90 med3(char *a, char *b, char *c,
d90b352 @antirez __P completely removed from pqsort.c/h
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91 int (*cmp) (const void *, const void *))
75fd597 @antirez psort.c/h added. This is a partial qsort implementation that Redis wi…
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92 {
93
94 return cmp(a, b) < 0 ?
95 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
96 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
97 }
98
99 static void
100 _pqsort(void *a, size_t n, size_t es,
d90b352 @antirez __P completely removed from pqsort.c/h
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101 int (*cmp) (const void *, const void *), void *lrange, void *rrange)
75fd597 @antirez psort.c/h added. This is a partial qsort implementation that Redis wi…
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102 {
103 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
104 size_t d, r;
105 int swaptype, swap_cnt, cmp_result;
106
107 loop: SWAPINIT(a, es);
108 swap_cnt = 0;
109 if (n < 7) {
110 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
111 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
112 pl -= es)
113 swap(pl, pl - es);
114 return;
115 }
116 pm = (char *) a + (n / 2) * es;
117 if (n > 7) {
118 pl = (char *) a;
119 pn = (char *) a + (n - 1) * es;
120 if (n > 40) {
121 d = (n / 8) * es;
122 pl = med3(pl, pl + d, pl + 2 * d, cmp);
123 pm = med3(pm - d, pm, pm + d, cmp);
124 pn = med3(pn - 2 * d, pn - d, pn, cmp);
125 }
126 pm = med3(pl, pm, pn, cmp);
127 }
128 swap(a, pm);
129 pa = pb = (char *) a + es;
130
131 pc = pd = (char *) a + (n - 1) * es;
132 for (;;) {
133 while (pb <= pc && (cmp_result = cmp(pb, a)) <= 0) {
134 if (cmp_result == 0) {
135 swap_cnt = 1;
136 swap(pa, pb);
137 pa += es;
138 }
139 pb += es;
140 }
141 while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) {
142 if (cmp_result == 0) {
143 swap_cnt = 1;
144 swap(pc, pd);
145 pd -= es;
146 }
147 pc -= es;
148 }
149 if (pb > pc)
150 break;
151 swap(pb, pc);
152 swap_cnt = 1;
153 pb += es;
154 pc -= es;
155 }
156 if (swap_cnt == 0) { /* Switch to insertion sort */
157 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
158 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
159 pl -= es)
160 swap(pl, pl - es);
161 return;
162 }
163
164 pn = (char *) a + n * es;
165 r = min(pa - (char *) a, pb - pa);
166 vecswap(a, pb - r, r);
167 r = min((size_t)(pd - pc), pn - pd - es);
168 vecswap(pb, pn - r, r);
169 if ((r = pb - pa) > es) {
170 void *_l = a, *_r = ((unsigned char*)a)+r-1;
171 if (!((lrange < _l && rrange < _l) ||
172 (lrange > _r && rrange > _r)))
173 _pqsort(a, r / es, es, cmp, lrange, rrange);
174 }
175 if ((r = pd - pc) > es) {
176 void *_l, *_r;
177
178 /* Iterate rather than recurse to save stack space */
179 a = pn - r;
180 n = r / es;
181
182 _l = a;
183 _r = ((unsigned char*)a)+r-1;
184 if (!((lrange < _l && rrange < _l) ||
185 (lrange > _r && rrange > _r)))
186 goto loop;
187 }
188 /* qsort(pn - r, r / es, es, cmp);*/
189 }
190
191 void
192 pqsort(void *a, size_t n, size_t es,
d90b352 @antirez __P completely removed from pqsort.c/h
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193 int (*cmp) (const void *, const void *), size_t lrange, size_t rrange)
75fd597 @antirez psort.c/h added. This is a partial qsort implementation that Redis wi…
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194 {
195 _pqsort(a,n,es,cmp,((unsigned char*)a)+(lrange*es),
196 ((unsigned char*)a)+((rrange+1)*es)-1);
197 }
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