From 23f985576863b39bb8d5562e6419a9497454c56c Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Sat, 10 Jul 2021 14:18:52 +1000
Subject: [PATCH] [common] ringbuffer: add forEach iterator

---
 common/include/common/ringbuffer.h |  5 +++++
 common/src/ringbuffer.c            | 14 ++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/common/include/common/ringbuffer.h b/common/include/common/ringbuffer.h
index c568c997..0c521196 100644
--- a/common/include/common/ringbuffer.h
+++ b/common/include/common/ringbuffer.h
@@ -19,6 +19,7 @@
  */
 
 #include <stddef.h>
+#include <stdbool.h>
 
 typedef struct RingBuffer * RingBuffer;
 
@@ -31,3 +32,7 @@ int    ringbuffer_getLength(const RingBuffer rb);
 int    ringbuffer_getStart (const RingBuffer rb);
 int    ringbuffer_getCount (const RingBuffer rb);
 void * ringbuffer_getValues(const RingBuffer rb);
+
+typedef bool (*RingBufferIterator)(int index, void * value, void * udata);
+void ringbuffer_forEach(const RingBuffer rb, RingBufferIterator fn,
+    void * udata);
diff --git a/common/src/ringbuffer.c b/common/src/ringbuffer.c
index ee2ca8cf..89bfca2d 100644
--- a/common/src/ringbuffer.c
+++ b/common/src/ringbuffer.c
@@ -88,3 +88,17 @@ void * ringbuffer_getValues(const RingBuffer rb)
 {
   return rb->values;
 }
+
+void ringbuffer_forEach(const RingBuffer rb, RingBufferIterator fn, void * udata)
+{
+  int index = rb->start;
+  for(int i = 0; i < rb->count; ++i)
+  {
+    void * value = rb->values + index * rb->valueSize;
+    if (++index == rb->length)
+      index = 0;
+
+    if (!fn(i, value, udata))
+      break;
+  }
+}