Initial commit

util/FIFO.h

@@ -0,0 +1,85 @@
+#ifndef UTIL_FIFO_H
+#define UTIL_FIFO_H
+
+#include <stddef.h>
+#include <util/atomic.h>
+
+typedef struct FIFOBuffer
+{
+  unsigned char *begin;
+  unsigned char *end;
+  unsigned char * volatile head;
+  unsigned char * volatile tail;
+} FIFOBuffer;
+
+inline bool fifo_isempty(const FIFOBuffer *f) {
+  return f->head == f->tail;
+}
+
+inline bool fifo_isfull(const FIFOBuffer *f) {
+  return ((f->head == f->begin) && (f->tail == f->end)) || (f->tail == f->head - 1);
+}
+
+inline void fifo_push(FIFOBuffer *f, unsigned char c) {
+  *(f->tail) = c;
+  
+  if (f->tail == f->end) {
+    f->tail = f->begin;
+  } else {
+    f->tail++;
+  }
+}
+
+inline unsigned char fifo_pop(FIFOBuffer *f) {
+  if(f->head == f->end) {
+    f->head = f->begin;
+    return *(f->end);
+  } else {
+    return *(f->head++);
+  }
+}
+
+inline void fifo_flush(FIFOBuffer *f) {
+  f->head = f->tail;
+}
+
+inline bool fifo_isempty_locked(const FIFOBuffer *f) {
+  bool result;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    result = fifo_isempty(f);
+  }
+  return result;
+}
+
+inline bool fifo_isfull_locked(const FIFOBuffer *f) {
+  bool result;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    result = fifo_isfull(f);
+  }
+  return result;
+}
+
+inline void fifo_push_locked(FIFOBuffer *f, unsigned char c) {
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    fifo_push(f, c);
+  }
+}
+
+inline unsigned char fifo_pop_locked(FIFOBuffer *f) {
+  unsigned char c;
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    c = fifo_pop(f);
+  }
+  return c;
+}
+
+inline void fifo_init(FIFOBuffer *f, unsigned char *buffer, size_t size) {
+  f->head = f->tail = f->begin = buffer;
+  f->end = buffer + size -1;
+}
+
+inline size_t fifo_len(FIFOBuffer *f) {
+  return f->end - f->begin;
+}
+
+#endif