bit masking, basic operations

bitmasking

/**
 * checks if a value has a given bit set to 1
 * @value the int / uint to test
 * @mask the bits to check
 **/
function bit_isset( value, mask )
{
    return ( value & mask ) != 0;
}

/**
 * sets a bit mask to a int / uint
 * @value the int / uint to set the bit mask onto
 * @mask the bits to set
 **/
function bit_set( value, mask )
{
    value |= mask;
    return value;
}

/**
 * clears a bit mask
 * @value the int / uint to clear
 * @mask the bits to clear
 **/
function bit_clear( value, mask )
{
    value &= ~mask;
    return value;
}

/**
 * toggles a bit mask ( 1s become 0s & 0s become 1s )
 * @value the int / uint to toggle
 * @mask the bits to toggle
 **/
function bit_toggle( value, mask )
{
    value ^= mask;
    return value;
}