duff's cowfiller

void cowfill( unsigned char *buffer, size_t length ){    unsigned char *ptr = buffer;    int n = length / 4;    if ( ! length ) {        return;    }    switch ( length % 4 ) {        while ( n-- ) {            ptr+= 4;        case 0:            ptr[3] = 0xEF;        case 3:            ptr[2] = 0xBE;        case 2:            ptr[1] = 0xAD;        case 1:            ptr[0] = 0xDE;        }    }}