From b8c7b8474683cc9370d316f7d7c3ed9799250677 Mon Sep 17 00:00:00 2001
From: damage <damage@devloop.de>
Date: Tue, 20 May 2025 22:23:19 +0200
Subject: [PATCH] implemented ringbuffer

---
 controller/ringbuffer.c | 55 +++++++++++++++++++++++++++++++++++++++++
 controller/ringbuffer.h | 11 +++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 controller/ringbuffer.c
 create mode 100644 controller/ringbuffer.h

diff --git a/controller/ringbuffer.c b/controller/ringbuffer.c
new file mode 100644
index 0000000..cc1d7c6
--- /dev/null
+++ b/controller/ringbuffer.c
@@ -0,0 +1,55 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ringbuffer.h"
+
+void _ringBufferIncReader(struct ringBuffer *buf) {
+  buf->reader++;
+  if (buf->reader >= buf->capacity) {
+    buf->reader = 0;
+  }
+}
+
+void _ringBufferIncWriter(struct ringBuffer *buf) {
+  buf->writer++;
+  if (buf->writer >= buf->capacity) {
+    buf->writer = 0;
+  }
+
+  if (buf->writer == buf->reader) {
+    // we incremented the writer and now it is equal to reader
+    // this means, the writer is overtaking the reader
+    // so push the reader forward, even if we are
+    // loosing data but this is how ring buffers work, eh?
+    _ringBufferIncReader(buf);
+  }
+}
+
+void ringBufferCreate(int capacity, struct ringBuffer *out) {
+  out->buffer = malloc(capacity * sizeof(uint8_t));
+  out->capacity = capacity;
+  out->reader = 0;
+  out->writer = 0;
+}
+
+void ringBufferDestroy(struct ringBuffer *buf) {
+  free(buf->buffer);
+}
+
+int ringBufferRead(struct ringBuffer *buf, uint8_t *out) {
+  if (buf->reader != buf->writer) {
+    // we have data to read
+    memcpy(out, &buf->buffer[buf->reader], sizeof(uint8_t));
+    _ringBufferIncReader(buf);
+    return 0;
+  } else {
+    // nothing to read
+    return 1;
+  }
+}
+
+void ringBufferWrite(struct ringBuffer *buf, uint8_t *in) {
+  memcpy(&buf->buffer[buf->writer], in, sizeof(uint8_t));
+  _ringBufferIncWriter(buf);
+}
diff --git a/controller/ringbuffer.h b/controller/ringbuffer.h
new file mode 100644
index 0000000..244182f
--- /dev/null
+++ b/controller/ringbuffer.h
@@ -0,0 +1,11 @@
+struct ringBuffer {
+  uint8_t *buffer;
+  int capacity;
+  int reader;
+  int writer;
+};
+
+void ringBufferCreate(int capacity, struct ringBuffer *out);
+void ringBufferDestroy(struct ringBuffer *buf);
+int ringBufferRead(struct ringBuffer *buf, uint8_t *out);
+void ringBufferWrite(struct ringBuffer *buf, uint8_t *in);