2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
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14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
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34 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
38 static const char rcsid[] =
39 "$FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.8 1999/08/28 00:01:35 peter Exp $";
40 #endif /* LIBC_SCCS and not lint */
44 typedef int cmp_t __P((const void *, const void *));
45 static inline char *med3 __P((char *, char *, char *, cmp_t *));
46 static inline void swapfunc __P((char *, char *, int, int));
48 #define min(a, b) (a) < (b) ? a : b
51 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
53 #define swapcode(TYPE, parmi, parmj, n) { \
54 long i = (n) / sizeof (TYPE); \
55 register TYPE *pi = (TYPE *) (parmi); \
56 register TYPE *pj = (TYPE *) (parmj); \
58 register TYPE t = *pi; \
64 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
65 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
68 swapfunc(a, b, n, swaptype)
73 swapcode(long, a, b, n)
75 swapcode(char, a, b, n)
79 if (swaptype == 0) { \
80 long t = *(long *)(a); \
81 *(long *)(a) = *(long *)(b); \
84 swapfunc(a, b, es, swaptype)
86 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
93 return cmp(a, b) < 0 ?
94 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
95 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
104 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
105 int d, r, swaptype, swap_cnt;
107 loop: SWAPINIT(a, es);
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;
116 pm = (char *)a + (n / 2) * es;
119 pn = (char *)a + (n - 1) * 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);
126 pm = med3(pl, pm, pn, cmp);
129 pa = pb = (char *)a + es;
131 pc = pd = (char *)a + (n - 1) * es;
133 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
141 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
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;
164 pn = (char *)a + n * es;
165 r = min(pa - (char *)a, pb - pa);
166 vecswap(a, pb - r, r);
167 r = min(pd - pc, pn - pd - es);
168 vecswap(pb, pn - r, r);
169 if ((r = pb - pa) > es)
170 qsort(a, r / es, es, cmp);
171 if ((r = pd - pc) > es) {
172 /* Iterate rather than recurse to save stack space */
177 /* qsort(pn - r, r / es, es, cmp);*/