Async io work

util/FIFO16.h

@@ -0,0 +1,87 @@
+#ifndef UTIL_FIFO16_H
+#define UTIL_FIFO16_H
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <util/atomic.h>
+
+typedef struct FIFOBuffer16
+{
+  size_t *begin;
+  size_t *end;
+  size_t * volatile head;
+  size_t * volatile tail;
+} FIFOBuffer16;
+
+inline bool fifo16_isempty(const FIFOBuffer16 *f) {
+  return f->head == f->tail;
+}
+
+inline bool fifo16_isfull(const FIFOBuffer16 *f) {
+  return ((f->head == f->begin) && (f->tail == f->end)) || (f->tail == f->head - 1);
+}
+
+inline void fifo16_push(FIFOBuffer16 *f, size_t c) {
+  *(f->tail) = c;
+
+  if (f->tail == f->end) {
+    f->tail = f->begin;
+  } else {
+    f->tail++;
+  }
+}
+
+inline size_t fifo16_pop(FIFOBuffer16 *f) {
+  if(f->head == f->end) {
+    f->head = f->begin;
+    return *(f->end);
+  } else {
+    return *(f->head++);
+  }
+}
+
+inline void fifo16_flush(FIFOBuffer16 *f) {
+  f->head = f->tail;
+}
+
+static inline bool fifo16_isempty_locked(const FIFOBuffer16 *f) {
+  bool result;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    result = fifo16_isempty(f);
+  }
+  return result;
+}
+
+static inline bool fifo16_isfull_locked(const FIFOBuffer16 *f) {
+  bool result;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    result = fifo16_isfull(f);
+  }
+  return result;
+}
+
+static inline void fifo16_push_locked(FIFOBuffer16 *f, size_t c) {
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    fifo16_push(f, c);
+  }
+}
+
+static inline size_t fifo16_pop_locked(FIFOBuffer16 *f) {
+  size_t c;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    c = fifo16_pop(f);
+  }
+  return c;
+}
+
+inline void fifo16_init(FIFOBuffer16 *f, size_t *buffer, size_t size) {
+  f->head = f->tail = f->begin = buffer;
+  f->end = buffer + (size/sizeof(size_t)) - 2;
+}
+
+inline size_t fifo16_len(FIFOBuffer16 *f) {
+  return ((f->end - f->begin))/sizeof(size_t);
+}
+
+#endif