SnglBurstUtils.c

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/*
*  Copyright (C) 2007 Jolien Creighton, Kipp Cannon, Patrick Brady, Saikat Ray-Majumder, Xavier Siemens
*
*  This program is free software; you can redistribute it and/or modify
*  it under the terms of the GNU General Public License as published by
*  the Free Software Foundation; either version 2 of the License, or
*  (at your option) any later version.
*
*  This program is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU General Public License for more details.
*
*  You should have received a copy of the GNU General Public License
*  along with with program; see the file COPYING. If not, write to the
*  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
*  MA  02110-1301  USA
*/
 
 
#include <string.h>
#include <lal/Date.h>
#include <lal/LIGOMetadataTables.h>
#include <lal/SnglBurstUtils.h>
#include <lal/XLALError.h>
 
 
/**
 * Compute the length of a linked list of SnglBurst objects.
 */
int XLALSnglBurstTableLength(SnglBurst *head)
{
        int length;
 
        for(length = 0; head; head = head->next)
                length++;
 
        return length;
}
 
 
/**
 * Sort a list of SnglBurst events into increasing order according to the
 * supplied comparison function.
 */
SnglBurst **XLALSortSnglBurst(
        SnglBurst **head,
        int (*comparefunc)(const SnglBurst * const *, const SnglBurst * const *)
)
{
        int i;
        int length;
        SnglBurst *event;
        SnglBurst **array;
        SnglBurst **next;
 
        /* empty list --> no-op */
        if(!*head)
                return head;
 
        /* construct an array of pointers into the list */
        length = XLALSnglBurstTableLength(*head);
        array = XLALCalloc(length, sizeof(*array));
        if(!array)
                XLAL_ERROR_NULL(XLAL_EFUNC);
        for(i = 0, event = *head; event; event = event->next)
                array[i++] = event;
 
        /* sort the array using the specified function */
        qsort(array, length, sizeof(*array), (int(*)(const void *, const void *)) comparefunc);
 
        /* re-link the list according to the sorted array */
        next = head;
        for(i = 0; i < length; i++, next = &(*next)->next)
                *next = array[i];
        *next = NULL;
 
        /* free the array */
        XLALFree(array);
 
        /* success */
        return head;
}
 
 
/**
 * Compare the peak times and SNRs of two SnglBurst events.
 */
 
 
int XLALCompareSnglBurstByPeakTimeAndSNR(
        const SnglBurst * const *a,
        const SnglBurst * const *b
)
{
        INT8 ta = XLALGPSToINT8NS(&(*a)->peak_time);
        INT8 tb = XLALGPSToINT8NS(&(*b)->peak_time);
        float snra = (*a)->snr;
        float snrb = (*b)->snr;
 
        if(ta > tb)
                return 1;
        if(ta < tb)
                return -1;
        /* ta == tb */
        if(snra > snrb)
                return 1;
        if(snra < snrb)
                return -1;
        /* snra == snrb */
        return 0;
}