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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 "ringbuffer.h"
#include "kernel/x86.h"
#include "lib/logger/log.h"
#include "kernel/spinlock.h"
#define RINGBUFFER_SIZE 10
static int size=RINGBUFFER_SIZE;
static volatile int front=RINGBUFFER_SIZE-1;
static volatile int back=RINGBUFFER_SIZE-1;
static volatile char buf[RINGBUFFER_SIZE];
static spinlock sl=9;
bool ringbuffer_put(char c)
{
x86_int_disable();
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"put wants lock");
lock_spin(sl);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"locked by put");
if((back-1+size)%size==front)
{
lock_release(sl);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by put");
x86_int_enable();
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(sl);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by put");
x86_int_enable();
return true;
}
bool ringbuffer_get(char *c)
{
x86_int_disable();
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"get wants lock");
lock_spin(sl);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"locked by get");
if(front==back)
{
lock_release(sl);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by get");
x86_int_enable();
*c='_';
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(sl);
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"unlocked by get");
x86_int_enable();
return true;
}
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