1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2
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 /* We need this because Solaris' version of qsort is broken and
33 * causes array bounds reads.
34 */
35
36 #include <stdlib.h>
37 #include "nsAlgorithm.h"
38 #include "nsQuickSort.h"
39
40 extern "C" {
41
42 #if !defined(DEBUG) && (defined(__cplusplus) || defined(__gcc))
43 # ifndef INLINE
44 # define INLINE inline
45 # endif
46 #else
47 # define INLINE
48 #endif
49
50 typedef int cmp_t(const void *, const void *, void *);
51 static INLINE char *med3(char *, char *, char *, cmp_t *, void *);
52 static INLINE void swapfunc(char *, char *, int, int);
53
54 /*
55 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
56 */
57 #define swapcode(TYPE, parmi, parmj, n) { \
58 long i = (n) / sizeof (TYPE); \
59 TYPE *pi = (TYPE *) (parmi); \
60 TYPE *pj = (TYPE *) (parmj); \
61 do { \
62 TYPE t = *pi; \
63 *pi++ = *pj; \
64 *pj++ = t; \
65 } while (--i > 0); \
66 }
67
68 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
69 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
70
71 static INLINE void
swapfunc(char * a,char * b,int n,int swaptype)72 swapfunc(char *a, char *b, int n, int swaptype)
73 {
74 if(swaptype <= 1)
75 swapcode(long, a, b, n)
76 else
77 swapcode(char, a, b, n)
78 }
79
80 #define swap(a, b) \
81 if (swaptype == 0) { \
82 long t = *(long *)(a); \
83 *(long *)(a) = *(long *)(b); \
84 *(long *)(b) = t; \
85 } else \
86 swapfunc((char *)a, (char*)b, (int)es, swaptype)
87
88 #define vecswap(a, b, n) if ((n) > 0) swapfunc((char *)a, (char *)b, (int)n, swaptype)
89
90 static INLINE char *
med3(char * a,char * b,char * c,cmp_t * cmp,void * data)91 med3(char *a, char *b, char *c, cmp_t* cmp, void *data)
92 {
93 return cmp(a, b, data) < 0 ?
94 (cmp(b, c, data) < 0 ? b : (cmp(a, c, data) < 0 ? c : a ))
95 :(cmp(b, c, data) > 0 ? b : (cmp(a, c, data) < 0 ? a : c ));
96 }
97
NS_QuickSort(void * a,unsigned int n,unsigned int es,cmp_t * cmp,void * data)98 void NS_QuickSort (
99 void *a,
100 unsigned int n,
101 unsigned int es,
102 cmp_t *cmp,
103 void *data
104 )
105 {
106 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
107 int d, r, swaptype;
108
109 loop: SWAPINIT(a, es);
110 /* Use insertion sort when input is small */
111 if (n < 7) {
112 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
113 for (pl = pm; pl > (char *)a && cmp(pl - es, pl, data) > 0;
114 pl -= es)
115 swap(pl, pl - es);
116 return;
117 }
118 /* Choose pivot */
119 pm = (char *)a + (n / 2) * es;
120 if (n > 7) {
121 pl = (char *)a;
122 pn = (char *)a + (n - 1) * es;
123 if (n > 40) {
124 d = (n / 8) * es;
125 pl = med3(pl, pl + d, pl + 2 * d, cmp, data);
126 pm = med3(pm - d, pm, pm + d, cmp, data);
127 pn = med3(pn - 2 * d, pn - d, pn, cmp, data);
128 }
129 pm = med3(pl, pm, pn, cmp, data);
130 }
131 swap(a, pm);
132 pa = pb = (char *)a + es;
133
134 pc = pd = (char *)a + (n - 1) * es;
135 /* loop invariants:
136 * [a, pa) = pivot
137 * [pa, pb) < pivot
138 * [pb, pc + es) unprocessed
139 * [pc + es, pd + es) > pivot
140 * [pd + es, pn) = pivot
141 */
142 for (;;) {
143 while (pb <= pc && (r = cmp(pb, a, data)) <= 0) {
144 if (r == 0) {
145 swap(pa, pb);
146 pa += es;
147 }
148 pb += es;
149 }
150 while (pb <= pc && (r = cmp(pc, a, data)) >= 0) {
151 if (r == 0) {
152 swap(pc, pd);
153 pd -= es;
154 }
155 pc -= es;
156 }
157 if (pb > pc)
158 break;
159 swap(pb, pc);
160 pb += es;
161 pc -= es;
162 }
163 /* Move pivot values */
164 pn = (char *)a + n * es;
165 r = XPCOM_MIN(pa - (char *)a, pb - pa);
166 vecswap(a, pb - r, r);
167 r = XPCOM_MIN<size_t>(pd - pc, pn - pd - es);
168 vecswap(pb, pn - r, r);
169 /* Recursively process partitioned items */
170 if ((r = pb - pa) > (int)es)
171 NS_QuickSort(a, r / es, es, cmp, data);
172 if ((r = pd - pc) > (int)es) {
173 /* Iterate rather than recurse to save stack space */
174 a = pn - r;
175 n = r / es;
176 goto loop;
177 }
178 /* NS_QuickSort(pn - r, r / es, es, cmp, data);*/
179 }
180
181 }
182
183 #undef INLINE
184 #undef swapcode
185 #undef SWAPINIT
186 #undef swap
187 #undef vecswap
188