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/* This code is part of the tng compression routines.
*
* Written by Daniel Spangberg
* Copyright (c) 2010, 2013, The GROMACS development team.
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "compression/warnmalloc.h"
#include "compression/merge_sort.h"
static void ms_inner(void *base, size_t size,
size_t start, size_t end,
int (*compar)(const void *v1,const void *v2,const void *private),
const void *private,
char *workarray)
{
int middle;
if ((end-start)>1)
{
char *cbase=(char *)base;
middle=start+(end-start)/2;
#if 0
printf("For start %d end %d obtained new middle: %d\n",start,end,middle);
#endif
ms_inner(base,size,
start,middle,
compar,private,workarray);
ms_inner(base,size,
middle,end,
compar,private,workarray);
#if 0
printf("For start %d end %d Before merge: Comparing element %d with %d\n",start,end,middle-1,middle);
#endif
if (compar(cbase+(middle-1)*size,cbase+middle*size,private)>0)
{
/* Merge to work array. */
int i, n=end-start;
int ileft=start;
int iright=middle;
for (i=0; i<n; i++)
{
if (ileft==middle)
{
memcpy(workarray+i*size,cbase+iright*size,size);
iright++;
}
else if (iright==end)
{
memcpy(workarray+i*size,cbase+ileft*size,size);
ileft++;
}
else
{
#if 0
printf("For start %d end %d In merge: Comparing element %d with %d\n",start,end,ileft,iright);
#endif
if (compar(cbase+ileft*size,cbase+iright*size,private)>0)
{
memcpy(workarray+i*size,cbase+iright*size,size);
iright++;
}
else
{
memcpy(workarray+i*size,cbase+ileft*size,size);
ileft++;
}
}
}
/* Copy result back. */
memcpy(cbase+start*size,workarray,(end-start)*size);
}
}
}
void Ptngc_merge_sort(void *base, size_t nmemb, size_t size,
int (*compar)(const void *v1,const void *v2,const void *private),
void *private)
{
char *warr=warnmalloc(nmemb*size);
ms_inner(base,size,0,nmemb,compar,private,warr);
free(warr);
}
#ifdef TEST
static int compint(const void *v1, const void *v2,const void *private)
{
const int *i1=(const int *)v1;
const int *i2=(const int *)v2;
if (*i1<*i2)
return -1;
else if (*i1>*i2)
return 1;
else
return 0;
}
static int qcompint(const void *v1, const void *v2)
{
return compint(v1,v2,NULL);
}
#define N 1000000
int main()
{
int *arr=warnmalloc(N*sizeof *arr);
int i;
for (i=0; i<N; i++)
scanf("%d",arr+i);
#if 1
merge_sort(arr,N,sizeof *arr,compint,NULL);
#else
qsort(arr,N,sizeof *arr,qcompint);
#endif
for (i=0; i<N; i++)
printf("%d %d\n",i,arr[i]);
return 0;
}
#endif
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