mirror of https://github.com/roytam1/kmeleon.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
100 lines
3.0 KiB
100 lines
3.0 KiB
7 years ago
|
/* qsort -- qsort interface implemented by faster quicksort.
|
||
|
|
J. L. Bentley and M. D. McIlroy, SPE 23 (1993) 1249-1265.
|
||
|
|
Copyright 1993, John Wiley.
|
||
|
|
*/
|
||
|
|
|
||
|
|
typedef int cmp_t(const char *, const char *, unsigned int);
|
||
|
|
|
||
|
|
/*assume sizeof(long) is a power of 2 */
|
||
|
|
#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
|
||
|
|
es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
|
||
|
|
#define swapcode(TYPE, parmi, parmj, n) { \
|
||
|
|
register TYPE *pi = (TYPE *) (parmi); \
|
||
|
|
register TYPE *pj = (TYPE *) (parmj); \
|
||
|
|
do { \
|
||
|
|
register TYPE t = *pi; \
|
||
|
|
*pi++ = *pj; \
|
||
|
|
*pj++ = t; \
|
||
|
|
} while ((n -= sizeof(TYPE)) > 0); \
|
||
|
|
}
|
||
|
|
#include <stddef.h>
|
||
|
|
static void swapfunc(char *a, char *b, size_t n, int swaptype)
|
||
|
|
{ if (swaptype <= 1) swapcode(long, a, b, n)
|
||
|
|
else swapcode(char, a, b, n)
|
||
|
|
}
|
||
|
|
#define swap(a, b) \
|
||
|
|
if (swaptype == 0) { \
|
||
|
|
t = *(long*)(a); \
|
||
|
|
*(long*)(a) = *(long*)(b); \
|
||
|
|
*(long*)(b) = t; \
|
||
|
|
} else \
|
||
|
|
swapfunc(a, b, es, swaptype)
|
||
|
|
|
||
|
|
#define vecswap(a, b, n) if (n > 0) swapfunc(a, b, n, swaptype)
|
||
|
|
|
||
|
|
#ifndef min
|
||
|
|
#define min(x, y) ((x)<=(y) ? (x) : (y))
|
||
|
|
#endif
|
||
|
|
|
||
|
|
static char *med3(char *a, char *b, char *c, cmp_t *cmp, unsigned int flag)
|
||
|
|
{ return cmp(a, b, flag) < 0 ?
|
||
|
|
(cmp(b, c, flag) < 0 ? b : cmp(a, c, flag) < 0 ? c : a)
|
||
|
|
: (cmp(b, c, flag) > 0 ? b : cmp(a, c, flag) > 0 ? c : a);
|
||
|
|
}
|
||
|
|
|
||
|
|
void quicksort(char *a, size_t n, size_t es, cmp_t *cmp, unsigned flag)
|
||
|
|
{
|
||
|
|
char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
|
||
|
|
int r, swaptype;
|
||
|
|
long t;
|
||
|
|
size_t s;
|
||
|
|
|
||
|
|
loop: SWAPINIT(a, es);
|
||
|
|
if (n < 7) { /* Insertion sort on smallest arrays */
|
||
|
|
for (pm = a + es; pm < a + n*es; pm += es)
|
||
|
|
for (pl = pm; pl > a && cmp(pl-es, pl, flag) > 0; pl -= es)
|
||
|
|
swap(pl, pl-es);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
pm = a + (n/2)*es; /* Small arrays, middle element */
|
||
|
|
if (n > 7) {
|
||
|
|
pl = a;
|
||
|
|
pn = a + (n-1)*es;
|
||
|
|
if (n > 40) { /* Big arrays, pseudomedian of 9 */
|
||
|
|
s = (n/8)*es;
|
||
|
|
pl = med3(pl, pl+s, pl+2*s, cmp, flag);
|
||
|
|
pm = med3(pm-s, pm, pm+s, cmp, flag);
|
||
|
|
pn = med3(pn-2*s, pn-s, pn, cmp, flag);
|
||
|
|
}
|
||
|
|
pm = med3(pl, pm, pn, cmp, flag); /* Mid-size, med of 3 */
|
||
|
|
}
|
||
|
|
swap(a, pm);
|
||
|
|
pa = pb = a + es;
|
||
|
|
pc = pd = a + (n-1)*es;
|
||
|
|
for (;;) {
|
||
|
|
while (pb <= pc && (r = cmp(pb, a, flag)) <= 0) {
|
||
|
|
if (r == 0) { swap(pa, pb); pa += es; }
|
||
|
|
pb += es;
|
||
|
|
}
|
||
|
|
while (pb <= pc && (r = cmp(pc, a, flag)) >= 0) {
|
||
|
|
if (r == 0) { swap(pc, pd); pd -= es; }
|
||
|
|
pc -= es;
|
||
|
|
}
|
||
|
|
if (pb > pc) break;
|
||
|
|
swap(pb, pc);
|
||
|
|
pb += es;
|
||
|
|
pc -= es;
|
||
|
|
}
|
||
|
|
pn = a + n*es;
|
||
|
|
s = min(pa-a, pb-pa ); vecswap(a, pb-s, s);
|
||
|
|
s = min(pd-pc, pn-pd-(long)es); vecswap(pb, pn-s, s);
|
||
|
|
if ((s = pb-pa) > es) quicksort(a, s/es, es, cmp, flag);
|
||
|
|
if ((s = pd-pc) > es) {
|
||
|
|
/* Iterate rather than recurse to save stack space */
|
||
|
|
a = pn - s;
|
||
|
|
n = s / es;
|
||
|
|
goto loop;
|
||
|
|
}
|
||
|
|
/* quicksort(pn-s, s/es, es, cmp, flag); */
|
||
|
|
}
|