#include "buffer.h"
// implementation for a FIFO-buffer with ints
// this very simple FIFO-buffer can only hold one int
#define FIFO_SIZE 100

// shared variables within this file
static int FIFO[FIFO_SIZE];
static unsigned int FIFO_count = 0;

// read and write pointers
unsigned int FIFO_write_p = 0;
unsigned int FIFO_read_p = 0;

/** incrementPointer
 *
 * add one and rotates if it overflows the buffersize
 */
unsigned int incrementPointer(unsigned int p)
{
    p++;
    if (p == FIFO_SIZE)
    {
        p = 0;
    }
    return p;
}

bool buffer_put(int i)
{
    bool notFull = !buffer_is_full();
    if (notFull)
    {
        FIFO[FIFO_write_p] = i;
        FIFO_count++;
        FIFO_write_p = incrementPointer(FIFO_write_p);
    }
    return notFull;
}

bool buffer_get(int *p)
{
    bool notEmpty = !buffer_is_empty();
    if (notEmpty)
    {
        *p = FIFO[FIFO_read_p];
        FIFO_count--;
        FIFO_read_p = incrementPointer(FIFO_read_p);
    }
    return notEmpty;
}

bool buffer_is_full(void)
{
    return (FIFO_count >= FIFO_SIZE);
}

bool buffer_is_empty(void)
{
    return (FIFO_count <= 0);
}

unsigned int number_of_elements_in_buffer()
{
    return FIFO_count;
}