void cowfill( unsigned char *buffer, size_t length )
{
    unsigned char *ptr = buffer + length - 1;

    if ( ! length ) {
        return;
    }

    switch ( length % 4 ) {

        while ( ptr >= buffer ) {

        case 0:
            *ptr-- = 0xEF;
        case 3:
            *ptr-- = 0xBE;
        case 2:
            *ptr-- = 0xAD;
        case 1:
            *ptr-- = 0xDE;

        }
    }
}