Assume the shared buffer is implemented as a circular array with two logical pointers: in and out

Assume the shared buffer is implemented as a circular array with two logical pointers: in and out

All the elements of the buffer can be used;

Both A and C

The buffer is empty when in $==$ out; the buffer is full when $(($in $+1)\%$ BUFFER SIZE$)==$ out;

The buffer is full when in $==$ out; the buffer is empty when $(($in $+1)\%$ BUFFER SIZE$)==$ out;