/*
 * Select.cpp
 *
 *  Created on: 13 May 2016
 *      Author: wentzelc
 */

// redA Libraries
#include "TimingCore.h"
#include "SelectCore.h"

// Standard C/C++ Libraries
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

//---------------------------------------------------------------------------

// Select Variables
fd_set      ReadTestFDS;
fd_set      WriteTestFDS;
fd_set      ReadFDS;
fd_set      WriteFDS;
int         MaxFD       = 0;
timeval     SelectTime;

//---------------------------------------------------------------------------

// Clear Select File Descriptors
void SelectClear()
{
    // Clear Select sets
    FD_ZERO( &ReadTestFDS );
    FD_ZERO( &WriteTestFDS );

    // Reset maximum File Descriptor
    MaxFD = 0;
}
//---------------------------------------------------------------------------

// Set Select timeout
void SelectConfig( long SelectTimeout )
{
    // Set Timeout
    SetInterval( &SelectTime, SelectTimeout );
}
//---------------------------------------------------------------------------

// Add Select File Descriptor
void SelectAdd( int FD, bool Read, bool Write )
{
    // Add Read select
    if (Read)
        FD_SET( FD, &ReadTestFDS );

    // Add Write Select
    if (Write)
        FD_SET( FD, &WriteTestFDS );

    // Check Maximum File Handle
    if (MaxFD <= FD)
        MaxFD = FD+1;
}
//---------------------------------------------------------------------------

void SelectRemove( int FD, bool Read, bool Write )
{
    // Remove from set for select read check
    if (Read)
        FD_CLR( FD, &ReadTestFDS);

    // Remove from set for select write check
    if (Write)
        FD_CLR( FD, &WriteTestFDS);

    // Check Maximum file handle
    if (FD == MaxFD) {
        for (int test = MaxFD-1; test >= 0; test--) {
            if (FD_ISSET( test, &ReadTestFDS ) || FD_ISSET( test, &WriteTestFDS )) {
                MaxFD = test+1;
                break;
            }
        }
    }
}
//---------------------------------------------------------------------------

bool SelectTest()
{
    int     Result  = 0;

    // Set Test sets
    ReadFDS     = ReadTestFDS;
    WriteFDS    = WriteTestFDS;

    // Perform select
    Result = select( MaxFD, &ReadFDS, &WriteFDS, (fd_set*)NULL, &SelectTime );
    if (Result < 0)
    {
        printf( "Select operation failed (%s)\n", strerror(errno) );
        return false;
    }

    // return success
    return (bool)Result;
}
//---------------------------------------------------------------------------

// Add Select File Descriptor
bool SelectCheck( int FD, bool &Read, bool &Write )
{
    // Add Read select
    Read = (bool)(FD_ISSET( FD, &ReadFDS ));

    // Add Write Select
    Write = (bool)(FD_ISSET( FD, &WriteFDS ));

    return (Read || Write);
}
//---------------------------------------------------------------------------