/*-
  * 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.
  * 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.
  */

 #if HAVE_CONFIG_H
 #include "clamav-config.h"
 #endif

 
 #include <stdlib.h>
 

 #include "clamav.h"

 #include "platform.h"

 #include "others.h"

 
 static inline char	*med3(char *, char *, char *, int (*)(const void *, const void *));

 static inline char	*med3_r(void *, char *, char *, char *, int (*)(const void *, const void *, const void *));

 static inline void	 swapfunc(char *, char *, int, int);
 
 /*
  * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  */
 #define swapcode(TYPE, parmi, parmj, n) { 		\
 	long i = (n) / sizeof (TYPE); 			\
 	register TYPE *pi = (TYPE *) (parmi); 		\
 	register TYPE *pj = (TYPE *) (parmj); 		\
 	do { 						\
 		register 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(a, b, n, swaptype)
 	char *a, *b;
 	int n, 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)
 

 #define CMP1(a, b) ((int)(*((uint32_t *)(a)) - *((uint32_t *)(b))))

 #define CMP(a, b)   (cmp ? (cmp(a, b)) : CMP1(a, b))

 #define CMP_R(arg, a, b)   (cmp ? (cmp(arg, a, b)) : CMP1(a, b))

 #define MED3(a, b, c, d)   (d ? (med3(a, b, c, d)) : (CMP1(a, b) < 0 ? (CMP1(b, c) < 0 ? (b) : (CMP1(a, c) < 0 ? (c) : (a))) : (CMP1(b, c) > 0 ? (b) : (CMP1(a, c) < 0 ? (a) : (c)))))

 #define MED3_R(arg, a, b, c, d)   (d ? (med3_r(arg, a, b, c, d)) : (CMP1(a, b) < 0 ? (CMP1(b, c) < 0 ? (b) : (CMP1(a, c) < 0 ? (c) : (a))) : (CMP1(b, c) > 0 ? (b) : (CMP1(a, c) < 0 ? (a) : (c)))))

 
 static inline char *
 med3(a, b, c, cmp)
 	char *a, *b, *c;
 	int (*cmp)(const void *, const void *);
 {
 	return CMP(a, b) < 0 ?
 	       (CMP(b, c) < 0 ? b : (CMP(a, c) < 0 ? c : a ))
               :(CMP(b, c) > 0 ? b : (CMP(a, c) < 0 ? a : c ));
 }
 

 static inline char *
 med3_r(arg, a, b, c, cmp)
 	void *arg;
 	char *a, *b, *c;
 	int (*cmp)(const void *, const void *, const void *);
 {
 	return CMP_R(arg, a, b) < 0 ?
 	       (CMP_R(arg, b, c) < 0 ? b : (CMP_R(arg, a, c) < 0 ? c : a ))
               :(CMP_R(arg, b, c) > 0 ? b : (CMP_R(arg, a, c) < 0 ? a : c ));
 }
 

 void cli_qsort(void *a, size_t n, size_t es, int (*cmp)(const void *, const void *))
 {
 	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(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);
 			pm = MED3(pm - d, pm, pm + d, cmp);
 			pn = MED3(pn - 2 * d, pn - d, pn, cmp);

 		}

 		pm = MED3(pl, pm, pn, cmp);

 	}
 	swap(a, pm);

 	pa = pb = (char *) a + es;

 	pc = pd = (char *) a + (n - 1) * es;

 	for (;;) {
 		while (pb <= pc && (r = CMP(pb, a)) <= 0) {
 			if (r == 0) {
 				swap_cnt = 1;
 				swap(pa, pb);
 				pa += es;
 			}
 			pb += es;
 		}
 		while (pb <= pc && (r = CMP(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(pl - es, pl) > 0; 
 			     pl -= es)
 				swap(pl, pl - es);
 		return;
 	}
 

 	pn = (char *) a + n * es;

 	r = MIN(pa - (char *)a, pb - pa);
 	vecswap(a, pb - r, r);

 	r = MIN((size_t) (pd - pc), (size_t) (pn - pd - es));

 	vecswap(pb, pn - r, r);

 	if ((size_t) (r = pb - pa) > es)

 		cli_qsort(a, r / es, es, cmp);

 	if ((size_t) (r = pd - pc) > es) { 

 		/* Iterate rather than recurse to save stack space */
 		a = pn - r;
 		n = r / es;
 		goto loop;
 	}
 /*		cli_qsort(pn - r, r / es, es, cmp);*/
 }

 
 void cli_qsort_r(void *a, size_t n, size_t es, int (*cmp)(const void*, const void *, const void *), void *arg)
 {
 	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_R(arg, 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_R(arg, pl, pl + d, pl + 2 * d, cmp);
 			pm = MED3_R(arg, pm - d, pm, pm + d, cmp);
 			pn = MED3_R(arg, pn - 2 * d, pn - d, pn, cmp);
 		}
 		pm = MED3_R(arg, pl, pm, pn, cmp);
 	}
 	swap(a, pm);
 	pa = pb = (char *) a + es;
 
 	pc = pd = (char *) a + (n - 1) * es;
 	for (;;) {
 		while (pb <= pc && (r = CMP_R(arg, pb, a)) <= 0) {
 			if (r == 0) {
 				swap_cnt = 1;
 				swap(pa, pb);
 				pa += es;
 			}
 			pb += es;
 		}
 		while (pb <= pc && (r = CMP_R(arg, 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_R(arg, pl - es, pl) > 0; 
 			     pl -= es)
 				swap(pl, pl - es);
 		return;
 	}
 
 	pn = (char *) a + n * es;
 	r = MIN(pa - (char *)a, pb - pa);
 	vecswap(a, pb - r, r);
 	r = MIN((size_t) (pd - pc), (size_t) (pn - pd - es));
 	vecswap(pb, pn - r, r);
 	if ((size_t) (r = pb - pa) > es)
 		cli_qsort_r(a, r / es, es, cmp, arg);
 	if ((size_t) (r = pd - pc) > es) { 
 		/* Iterate rather than recurse to save stack space */
 		a = pn - r;
 		n = r / es;
 		goto loop;
 	}
 /*		cli_qsort_r(pn - r, r / es, es, cmp);*/
 }