/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "igraph_qsort.h"
#ifdef _MSC_VER
/* MSVC does not have inline when compiling C source files */
#define inline __inline
#define __unused
#endif
#ifndef __unused
#define __unused __attribute__ ((unused))
#endif
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
/*#include <sys/cdefs.h> */
#include <stdlib.h>
#ifdef I_AM_QSORT_R
typedef int cmp_t(void *, const void *, const void *);
#else
typedef int cmp_t(const void *, const void *);
#endif
static inline char *med3(char *, char *, char *, cmp_t *, void *);
static inline void swapfunc(char *, char *, int, int);
#define igraph_min(a, b) (a) < (b) ? a : b
/*
* Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
*/
#define swapcode(TYPE, parmi, parmj, n) { \
long i = (n) / sizeof (TYPE); \
TYPE *pi = (TYPE *) (parmi); \
TYPE *pj = (TYPE *) (parmj); \
do { \
TYPE t = *pi; \
*pi++ = *pj; \
*pj++ = t; \
} while (--i > 0); \
}
#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
static inline void
swapfunc(char *a, char *b, int n, int swaptype)
{
if (swaptype <= 1)
swapcode(long, a, b, n)
else
swapcode(char, a, b, n)
}
#define swap(a, b) \
if (swaptype == 0) { \
long 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)
#ifdef I_AM_QSORT_R
#define CMP(t, x, y) (cmp((t), (x), (y)))
#else
#define CMP(t, x, y) (cmp((x), (y)))
#endif
static inline char *
med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
#ifndef I_AM_QSORT_R
__unused
#endif
) {
return CMP(thunk, a, b) < 0 ?
(CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
: (CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
}
#ifdef I_AM_QSORT_R
void
igraph_qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
#else
#define thunk NULL
void
igraph_qsort(void *a, size_t n, size_t es, cmp_t *cmp)
#endif
{
char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
int d, r, swaptype, swap_cnt;
loop: SWAPINIT(a, es);
swap_cnt = 0;
if (n < 7) {
for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
for (pl = pm;
pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
pl -= es) {
swap(pl, pl - es);
}
return;
}
pm = (char *)a + (n / 2) * es;
if (n > 7) {
pl = a;
pn = (char *)a + (n - 1) * es;
if (n > 40) {
d = (n / 8) * es;
pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
pm = med3(pm - d, pm, pm + d, cmp, thunk);
pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
}
pm = med3(pl, pm, pn, cmp, thunk);
}
swap(a, pm);
pa = pb = (char *)a + es;
pc = pd = (char *)a + (n - 1) * es;
for (;;) {
while (pb <= pc && (r = CMP(thunk, pb, a)) <= 0) {
if (r == 0) {
swap_cnt = 1;
swap(pa, pb);
pa += es;
}
pb += es;
}
while (pb <= pc && (r = CMP(thunk, pc, a)) >= 0) {
if (r == 0) {
swap_cnt = 1;
swap(pc, pd);
pd -= es;
}
pc -= es;
}
if (pb > pc) {
break;
}
swap(pb, pc);
swap_cnt = 1;
pb += es;
pc -= es;
}
if (swap_cnt == 0) { /* Switch to insertion sort */
for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
for (pl = pm;
pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
pl -= es) {
swap(pl, pl - es);
}
return;
}
pn = (char *)a + n * es;
r = igraph_min(pa - (char *)a, pb - pa);
vecswap(a, pb - r, r);
r = igraph_min((size_t)(pd - pc), (size_t)(pn - pd - es));
vecswap(pb, pn - r, r);
if ((size_t)(r = pb - pa) > es)
#ifdef I_AM_QSORT_R
igraph_qsort_r(a, r / es, es, thunk, cmp);
#else
igraph_qsort(a, r / es, es, cmp);
#endif
if ((size_t)(r = pd - pc) > es) {
/* Iterate rather than recurse to save stack space */
a = pn - r;
n = r / es;
goto loop;
}
/* qsort(pn - r, r / es, es, cmp);*/
}