2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #define min(a, b) (a) < (b) ? (a) : (b)
36 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
38 #define swapcode(TYPE, parmi, parmj, n) { \
39 long i = (n) / sizeof (TYPE); \
40 register TYPE *pi = (TYPE *) (parmi); \
41 register TYPE *pj = (TYPE *) (parmj); \
43 register TYPE t = *pi; \
49 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
50 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
53 swapfunc(char *a
, char *b
, int n
, int swaptype
)
56 swapcode(long, a
, b
, n
)
58 swapcode(char, a
, b
, n
)
62 if (swaptype == 0) { \
63 long t = *(long *)(a); \
64 *(long *)(a) = *(long *)(b); \
67 swapfunc(a, b, es, swaptype)
69 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
71 #define CMP(x, y) (cmp((x), (y)))
73 static __inline
char *
74 med3(char *a
, char *b
, char *c
, int (__cdecl
*cmp
)(const void*, const void*))
76 return CMP(a
, b
) < 0 ?
77 (CMP(b
, c
) < 0 ? b
: (CMP(a
, c
) < 0 ? c
: a
))
78 :(CMP(b
, c
) > 0 ? b
: (CMP(a
, c
) < 0 ? a
: c
));
83 * First, set up some global parameters for qst to share. Then, quicksort
84 * with qst(), and then a cleanup insertion sort ourselves. Sound simple?
91 qsort(void *a
, size_t n
, size_t es
, int (__cdecl
*cmp
)(const void*, const void*))
93 char *pa
, *pb
, *pc
, *pd
, *pl
, *pm
, *pn
;
94 int d
, r
, swaptype
, swap_cnt
;
96 loop
: SWAPINIT(a
, es
);
99 for (pm
= (char *)a
+ es
; pm
< (char *)a
+ n
* es
; pm
+= es
)
100 for (pl
= pm
; pl
> (char *)a
&& CMP(pl
- es
, pl
) > 0;
105 pm
= (char *)a
+ (n
/ 2) * es
;
108 pn
= (char *)a
+ (n
- 1) * es
;
111 pl
= med3(pl
, pl
+ d
, pl
+ 2 * d
, cmp
);
112 pm
= med3(pm
- d
, pm
, pm
+ d
, cmp
);
113 pn
= med3(pn
- 2 * d
, pn
- d
, pn
, cmp
);
115 pm
= med3(pl
, pm
, pn
, cmp
);
118 pa
= pb
= (char *)a
+ es
;
120 pc
= pd
= (char *)a
+ (n
- 1) * es
;
122 while (pb
<= pc
&& (r
= CMP(pb
, a
)) <= 0) {
130 while (pb
<= pc
&& (r
= CMP(pc
, a
)) >= 0) {
145 if (swap_cnt
== 0) { /* Switch to insertion sort */
146 for (pm
= (char *)a
+ es
; pm
< (char *)a
+ n
* es
; pm
+= es
)
147 for (pl
= pm
; pl
> (char *)a
&& CMP(pl
- es
, pl
) > 0;
153 pn
= (char *)a
+ n
* es
;
154 r
= min(pa
- (char *)a
, pb
- pa
);
155 vecswap(a
, pb
- r
, r
);
156 r
= min(pd
- pc
, pn
- pd
- es
);
157 vecswap(pb
, pn
- r
, r
);
158 if ((r
= pb
- pa
) > es
)
159 qsort(a
, r
/ es
, es
, cmp
);
160 if ((r
= pd
- pc
) > es
) {
161 /* Iterate rather than recurse to save stack space */