/*
 *    dvector2.c
 *    $Id: dvector2.c,v 1.1 2009/10/30 16:31:40 daichi Exp $
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include "dvector2.h"

double *
dvector (int size)
{
	double *v;
	
	v = (double *)calloc(size + 1, sizeof(double));
	
	if (v == NULL)
	{
		perror("dvector");
		return NULL;
	}
	/* record size */
	*((int *)v) = size;
	v += 1;
	
	return v;
}

void
free_dvector (double *v)
{
	free(v - 1);
}


double *
resize_dvector (double *v, int newsize)
{
	int i, size = vsize(v);

	v = (double *)realloc(v - 1, (newsize + 1) * sizeof(double));
	
	if (v == NULL)
	{
		perror("resize_dvector");
		return NULL;
	}
	/* record size */
	*((int *)v) = newsize;
	v += 1;
	for (i = size; i < newsize; i++)
		v[i] = 0;	/* zero clear */
	
	return v;
}

void
alloc_dvector (double **v, int newsize) /* guarantee v has size newsize */
{
	if (newsize > vsize(*v))
		*v = resize_dvector(*v, newsize);
}

#if 0

int
main (int argc, char *argv[])
{
	int i, n = atoi(argv[1]);

	double *v = dvector(n);

	printf("size = %d\n", vsize(v));
	for (i = 0; i < vsize(v); i++)
		v[i] = i / 10.0;
	for (i = 0; i < vsize(v); i++)
		printf("v[%d] = %lg\n", i, v[i]);

	v = resize_dvector(v, 20);
	printf("size = %d\n", vsize(v));
	for (i = 0; i < vsize(v); i++)
		printf("v[%d] = %lg\n", i, v[i]);
	
	return 0;
}

#endif