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29 * $FreeBSD: src/sys/libkern/qsort.c,v 1.15 2004/07/15 23:58:23 glebius Exp $
32 #include <sys/param.h>
33 #include <sys/libkern.h>
36 typedef int cmp_t(void *, const void *, const void *);
38 typedef int cmp_t(const void *, const void *);
40 static __inline char *med3(char *, char *, char *, cmp_t *, void *);
41 static __inline void swapfunc(char *, char *, int, int);
43 #define min(a, b) (a) < (b) ? (a) : (b)
46 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
48 #define swapcode(TYPE, parmi, parmj, n) { \
49 long i = (n) / sizeof (TYPE); \
50 TYPE *pi = (TYPE *) (parmi); \
51 TYPE *pj = (TYPE *) (parmj); \
59 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
60 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
63 swapfunc(char *a, char *b, int n, int swaptype)
66 swapcode(long, a, b, n)
68 swapcode(char, a, b, n)
72 if (swaptype == 0) { \
73 long t = *(long *)(a); \
74 *(long *)(a) = *(long *)(b); \
77 swapfunc(a, b, es, swaptype)
79 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
82 #define CMP(t, x, y) (cmp((t), (x), (y)))
84 #define CMP(t, x, y) (cmp((x), (y)))
87 static __inline char *
88 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
94 return CMP(thunk, a, b) < 0 ?
95 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
96 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
101 kqsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
105 kqsort(void *a, size_t n, size_t es, cmp_t *cmp)
108 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
109 int d, r, swaptype, swap_cnt;
111 loop: SWAPINIT(a, es);
114 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
115 for (pl = pm; pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
120 pm = (char *)a + (n / 2) * es;
123 pn = (char *)a + (n - 1) * es;
126 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
127 pm = med3(pm - d, pm, pm + d, cmp, thunk);
128 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
130 pm = med3(pl, pm, pn, cmp, thunk);
133 pa = pb = (char *)a + es;
135 pc = pd = (char *)a + (n - 1) * es;
137 while (pb <= pc && (r = CMP(thunk, pb, a)) <= 0) {
145 while (pb <= pc && (r = CMP(thunk, pc, a)) >= 0) {
160 if (swap_cnt == 0) { /* Switch to insertion sort */
161 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
162 for (pl = pm; pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
168 pn = (char *)a + n * es;
169 r = min(pa - (char *)a, pb - pa);
170 vecswap(a, pb - r, r);
171 r = min(pd - pc, pn - pd - es);
172 vecswap(pb, pn - r, r);
173 if ((r = pb - pa) > es)
175 kqsort_r(a, r / es, es, thunk, cmp);
177 kqsort(a, r / es, es, cmp);
179 if ((r = pd - pc) > es) {
180 /* Iterate rather than recurse to save stack space */