2 * Copyright (c) 1992, 1993
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30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.15 2008/01/14 09:21:34 das Exp $");
39 typedef int cmp_t(void *, const void *, const void *);
41 typedef int cmp_t(const void *, const void *);
43 static inline char *med3(char *, char *, char *, cmp_t *, void *);
44 static inline void swapfunc(char *, char *, int, int);
46 #define min(a, b) (a) < (b) ? a : b
49 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
51 #define swapcode(TYPE, parmi, parmj, n) { \
52 long i = (n) / sizeof (TYPE); \
53 TYPE *pi = (TYPE *) (parmi); \
54 TYPE *pj = (TYPE *) (parmj); \
62 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
63 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
66 swapfunc(a, b, n, swaptype)
71 swapcode(long, a, b, n)
73 swapcode(char, a, b, n)
77 if (swaptype == 0) { \
78 long t = *(long *)(a); \
79 *(long *)(a) = *(long *)(b); \
82 swapfunc(a, b, es, swaptype)
84 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
87 #define CMP(t, x, y) (cmp((t), (x), (y)))
89 #define CMP(t, x, y) (cmp((x), (y)))
93 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
95 __unused // XXX what ?
99 return CMP(thunk, a, b) < 0 ?
100 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
101 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
106 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
110 qsort(void *a, size_t n, size_t es, cmp_t *cmp)
113 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
116 int swaptype, swap_cnt;
118 loop: SWAPINIT(a, es);
121 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
123 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
128 pm = (char *)a + (n / 2) * es;
131 pn = (char *)a + (n - 1) * es;
134 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
135 pm = med3(pm - d, pm, pm + d, cmp, thunk);
136 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
138 pm = med3(pl, pm, pn, cmp, thunk);
141 pa = pb = (char *)a + es;
143 pc = pd = (char *)a + (n - 1) * es;
145 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
146 if (cmp_result == 0) {
153 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
154 if (cmp_result == 0) {
168 if (swap_cnt == 0) { /* Switch to insertion sort */
169 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
171 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
177 pn = (char *)a + n * es;
178 r = min(pa - (char *)a, pb - pa);
179 vecswap(a, pb - r, r);
180 r = min(pd - pc, pn - pd - es);
181 vecswap(pb, pn - r, r);
182 if ((r = pb - pa) > es)
184 qsort_r(a, r / es, es, thunk, cmp);
186 qsort(a, r / es, es, cmp);
188 if ((r = pd - pc) > es) {
189 /* Iterate rather than recurse to save stack space */
194 /* qsort(pn - r, r / es, es, cmp);*/