2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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13 * 3. Neither the name of the University nor the names of its contributors
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15 * without specific prior written permission.
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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("$FreeBSD$");
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 *, size_t, 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 size_t i = (n) / sizeof (TYPE); \
53 TYPE *pi = (TYPE *) (parmi); \
54 TYPE *pj = (TYPE *) (parmj); \
62 #define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \
63 ((char *)a - (char *)0) % sizeof(TYPE) || \
64 es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1;
67 swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int)
69 if (swaptype_long <= 1)
70 swapcode(long, a, b, n)
71 else if (swaptype_int <= 1)
72 swapcode(int, a, b, n)
74 swapcode(char, a, b, n)
78 if (swaptype_long == 0) { \
79 long t = *(long *)(a); \
80 *(long *)(a) = *(long *)(b); \
82 } else if (swaptype_int == 0) { \
83 int t = *(int *)(a); \
84 *(int *)(a) = *(int *)(b); \
87 swapfunc(a, b, es, swaptype_long, swaptype_int)
89 #define vecswap(a, b, n) \
90 if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int)
93 #define CMP(t, x, y) (cmp((t), (x), (y)))
95 #define CMP(t, x, y) (cmp((x), (y)))
99 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
105 return CMP(thunk, a, b) < 0 ?
106 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
107 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
112 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
116 qsort(void *a, size_t n, size_t es, cmp_t *cmp)
119 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
122 int swaptype_long, swaptype_int, swap_cnt;
124 loop: SWAPINIT(long, a, es);
125 SWAPINIT(int, a, es);
128 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
130 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
135 pm = (char *)a + (n / 2) * es;
138 pn = (char *)a + (n - 1) * es;
140 size_t d = (n / 8) * es;
142 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
143 pm = med3(pm - d, pm, pm + d, cmp, thunk);
144 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
146 pm = med3(pl, pm, pn, cmp, thunk);
149 pa = pb = (char *)a + es;
151 pc = pd = (char *)a + (n - 1) * es;
153 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
154 if (cmp_result == 0) {
161 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
162 if (cmp_result == 0) {
176 if (swap_cnt == 0) { /* Switch to insertion sort */
177 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
179 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
185 pn = (char *)a + n * es;
186 d1 = MIN(pa - (char *)a, pb - pa);
187 vecswap(a, pb - d1, d1);
188 d1 = MIN(pd - pc, pn - pd - es);
189 vecswap(pb, pn - d1, d1);
194 /* Recurse on left partition, then iterate on right partition */
197 qsort_r(a, d1 / es, es, thunk, cmp);
199 qsort(a, d1 / es, es, cmp);
203 /* Iterate rather than recurse to save stack space */
204 /* qsort(pn - d2, d2 / es, es, cmp); */
210 /* Recurse on right partition, then iterate on left partition */
213 qsort_r(pn - d2, d2 / es, es, thunk, cmp);
215 qsort(pn - d2, d2 / es, es, cmp);
219 /* Iterate rather than recurse to save stack space */
220 /* qsort(a, d1 / es, es, cmp); */