feat: add ringInit and ringClear

src/ring.c

@@ -0,0 +1,58 @@
+#include "ring.h"
+
+void ringInit(RingBuffer* r, uint8* backingBuffer, usize capacity)
+{
+    r->data = backingBuffer;
+    r->capacity = capacity;
+    r->head = 0;
+    r->count = 0;
+}
+
+void ringClear(RingBuffer* r)
+{
+    r->head = 0;
+    r->count = 0;
+}
+
+bool ringIsEmpty(const RingBuffer* r) { return r->count == 0; }
+bool ringIsFull(const RingBuffer* r) { return r->count == r->capacity; }
+usize ringCount(const RingBuffer* r) { return r->count; }
+usize ringCapacity(const RingBuffer* r) { return r->capacity; }
+usize ringFreeSpace(const RingBuffer* r) { return r->capacity - r->count; }
+
+bool ringPush(RingBuffer* r, uint8 byte)
+{
+    if (ringIsFull(r))
+        return false;
+    usize tail = (r->head + r->count) % r->capacity;
+    r->data[tail] = byte;
+    r->count++;
+    return true;
+}
+
+bool ringPop(RingBuffer* r, uint8* out)
+{
+    if (ringIsEmpty(r))
+        return false;
+    if (out)
+        *out = r->data[r->head];
+    r->head = (r->head + 1) % r->capacity;
+    r->count--;
+    return true;
+}
+
+usize ringWrite(RingBuffer* r, const uint8* data, usize len)
+{
+    usize written = 0;
+    while (written < len && ringPush(r, data[written]))
+        written++;
+    return written;
+}
+
+usize ringRead(RingBuffer* r, uint8* data, usize len)
+{
+    usize readCount = 0;
+    while (readCount < len && ringPop(r, &data[readCount]))
+        readCount++;
+    return readCount;
+}