Merge maple-native changes into portable

This compiles for both maple and maple_native but is untested.

1 files changed, 57 insertions, 0 deletions

diff --git a/libmaple/ring_buffer.h b/libmaple/ring_buffer.h
new file mode 100644
index 0000000..95b9dd8
--- /dev/null
+++ b/libmaple/ring_buffer.h
@@ -0,0 +1,57 @@
+/**
+ *  @brief simple circular buffer
+ */
+
+#ifndef _RING_BUFFER_H_
+#define _RING_BUFFER_H_
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+/* The buffer is empty when head == tail.
+ * The buffer is full when the head is one byte in front of the tail
+ * The total buffer size must be a power of two
+ * One byte is left free to distinguish empty from full */
+typedef struct ring_buffer {
+    uint32 head;
+    uint32 tail;
+    uint8 size;
+    uint8 *buf;
+} ring_buffer;
+
+static inline void rb_init(ring_buffer *rb, uint8 size, uint8 *buf) {
+   ASSERT(IS_POWER_OF_TWO(size));
+   rb->head = 0;
+   rb->tail = 0;
+   rb->size = size;
+   rb->buf = buf;
+}
+
+static inline void rb_insert(ring_buffer *rb, uint8 element) {
+   rb->buf[(rb->tail)++] = element;
+   rb->tail &= (rb->size - 1);
+}
+
+static inline uint8 rb_remove(ring_buffer *rb) {
+   uint8 ch = rb->buf[rb->head++];
+   rb->head &= (rb->size - 1);
+   return ch;
+}
+
+static inline uint32 rb_full_count(ring_buffer *rb) {
+   return rb->tail - rb->head;
+}
+
+static inline void  rb_reset(ring_buffer *rb) {
+   rb->tail = rb->head;
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+
+#endif
+