// AT90USB/ringbuffer.c
// Simple Ring-Buffer (FIFO) for Elements of type char
// S. Salewski, 19-MAR-2007

/*
t-> o
    o <-w
    x 
    x <-r
b-> x
*/

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "ringbuffer.h"


#define ringbuffer_size     2048
#define memory_size         65536


#define t &buf[ringbuffer_size - 1]
#define b &buf[0]

char buf[ringbuffer_size];
int rb_count;
char *memory;
int pos_mem;
int pos_head;


//char *t = &buf[ringbuffer_size - 1];
//char *b = &buf[0];

char *r; // position from where we can read (if rb_count > 0)
char *w; // next free position (if rb_count < ringbuffer_size))

void rb_init()
{
    r = b;
    w = b;
    rb_count = 0;
    memory = (char*)malloc(memory_size);
    pos_mem = 0;
    pos_head = 0;
}

void rb_flush(){
    FILE *file;

    while(!rb_isempty()){
        memory[pos_mem++] = rb_get();
    }
    printf("write out.smc\n");
    file = fopen("out.smc","w");
    fwrite(memory,memory_size,1,file);
    fclose(file);
}

char rb_get(void)
{
  rb_count--;
  if (r > t)
    r = b;
  return *r++;
}


char rb_read(void)
{
  if (r > t) r = b;
  return *r++;
}


void rb_put(char el)
{
  pos_head++;
  rb_count++;

  if ( rb_count > ringbuffer_size)
    memory[pos_mem++]=el;

  printf("rb_count=%i pos_head=0x%06x add_mem=0x%06x\n",rb_count, pos_head,pos_mem);

  if (w > t){
        w = b;
  }
  *w++ = el;
}