#include "fifo.h"


void fifo_init(FIFO *fifo, uint16_t bufferlength)
{
    fifo->buffer_ptr = calloc(bufferlength, sizeof(uint8_t));
    fifo->read_index = 0;
    fifo->write_index = 0;
    fifo->bufferlength = bufferlength;
}

void fifo_deinit(FIFO *fifo)
{
    free(fifo->buffer_ptr);
}

uint16_t fifo_get_buffersize(FIFO *fifo)
{
    return fifo->bufferlength;
}

uint16_t fifo_bytes_available(FIFO *fifo)
{
    if (fifo->write_index > fifo->read_index){
        return (fifo->write_index - fifo->read_index);
    }
    else if (fifo->write_index < fifo->read_index){
        return (fifo_get_buffersize(fifo) - (fifo->read_index - fifo->write_index));
    }
    else {  // read_index == write_index
        return 0;
    }
}

//uint16_t fifo_lines_available(FIFO *fifo){}

void fifo_move_read_index(FIFO *fifo)
{
    fifo->read_index++;
    fifo->read_index %= fifo_get_buffersize(fifo);
}

void fifo_move_write_index(FIFO *fifo)
{
    fifo->write_index++;
    fifo->write_index %= fifo_get_buffersize(fifo);
}

void fifo_get_byte(FIFO *fifo, uint8_t *data_sink)
{
    if(fifo_bytes_available(fifo)){
        *data_sink = fifo->buffer_ptr[fifo->read_index];
        fifo_move_read_index(fifo);
    }
}

void fifo_put_byte(FIFO *fifo, uint8_t *data_source)
{
    fifo->buffer_ptr[fifo->write_index] = *data_source;
    fifo_move_write_index(fifo);
    if(fifo->read_index == fifo->write_index){  // buffer overflow case
        fifo_move_read_index(fifo);
    }
}