fifo.c

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#include "fifo.h"
#include <string.h>
 
void fifo_init(Fifo *f, uint32_t len, uint32_t esize, uint8_t *data, FifoLockFn lockFn) {
    f->len = len;
    f->esize = esize;
    f->data = data;
    f->read = 0;
    f->write = 0;
    f->level = 0;
    f->lockFn = lockFn;
}
 
#define FIFO_GET_ELEMENT_PTR(f, i) ((void *)(f->data + (f->esize * i)))
#define FIFO_ADVANCE_INDEX(f, k) ((k) >= ((f)->len - 1)) ? 0 : ((k) + 1)
 
bool fifo_push(Fifo * f, void const * item) {
    // the storage is full
    if (f->level == f->len) {
        return false;
    }
 
    // enter critical section
    f->lockFn(true);
 
    // get destination pointer
    void * dst = FIFO_GET_ELEMENT_PTR(f, f->write);
 
    // store the data
    memcpy(dst, item, f->esize);
 
    // increment utilization
    f->level++;
 
    // advance write index
    f->write = FIFO_ADVANCE_INDEX(f, f->write);
 
    // leave critical section
    f->lockFn(false);
 
    return true;
}
 
uint32_t fifo_get_level(const Fifo * f) {
    return f->level;
}
 
bool fifo_pop(Fifo * f, void * item) {
        // the storage is full
    if (f->level == 0) {
        return false;
    }
 
    // enter critical section
    f->lockFn(true);
 
    // get source pointer
    void * src = FIFO_GET_ELEMENT_PTR(f, f->read);
 
    // read the data
    memcpy(item, src, f->esize);
 
    // decrement utilization
    f->level--;
 
    // advance read index
    f->read = FIFO_ADVANCE_INDEX(f, f->read);
 
    // leave critical section
    f->lockFn(false);
 
    return true;
}
 
void fifo_clear(Fifo * f) {
    // enter critical section
    f->lockFn(true);
 
    // reset level and indices
    f->level = 0;
    f->read = 0;
    f->write = 0;
 
    // leave critical section
    f->lockFn(false);
}