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// can handle one buffer for a start.
// later make it reentrant and manage multiple buffers!
// todo: syncing access to buffer.
#define FOOLOS_MODULE_NAME "ringbuffer"
#include "lib/bool/bool.h"
#include "lib/logger/log.h"
static volatile int front;
static volatile int back;
static volatile int size;
#define RINGBUFFER_SIZE 10
static volatile char buf[RINGBUFFER_SIZE];
bool ringbuffer_selftest();
void ringbuffer_init()
{
size=RINGBUFFER_SIZE;
front=size-1;
back=size-1;
// ringbuffer_selftest();
// while(1);
}
bool ringbuffer_put(char c)
{
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"put wants lock)");
lock_spin(3);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"locked by put)");
if((back-1+size)%size==front)
{
lock_release(3);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by put)");
return false;
}
buf[back]=c;
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"put %d %d (%c)", back, front,c);
back--;
back+=size;
back%=size;
lock_release(3);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by put)");
return true;
}
bool ringbuffer_get(char *c)
{
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"get wants lock)");
lock_spin(3);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"locked by get)");
if(front==back)
{
lock_release(3);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by get)");
return false;
}
*c=buf[front];
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"get %d %d (%c)", back, front,*c);
front--;
front+=size;
front%=size;
lock_release(3);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by get)");
return true;
}
bool ringbuffer_selftest()
{
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"ringbuffer selftest");
char c;
ringbuffer_put('a');
ringbuffer_put('b');
ringbuffer_put('c');
ringbuffer_put('d');
ringbuffer_put('e');
ringbuffer_get(&c);
ringbuffer_get(&c);
ringbuffer_get(&c);
ringbuffer_get(&c);
ringbuffer_get(&c);
ringbuffer_get(&c);
ringbuffer_get(&c);
}
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