Preserve circular buffer item semantics

src/lib/circular_buffer.c

@@ -74,8 +74,8 @@ bool circular_buffer_get(const CircularBuffer *cb, size_t i, void *item) {
     return true;
 }
 
-bool circular_buffer_pop(CircularBuffer *cb, size_t i, void *item) {
-    if (!circular_buffer_get(cb, i, item)) {
+bool circular_buffer_pop(CircularBuffer *cb, void *item) {
+    if (!circular_buffer_get(cb, 0, item)) {
         return false;
     }
 
@@ -96,7 +96,7 @@ void circular_buffer_iterate(
 
     size_t i = cb->tail;
     do {
-        callback(&cb->buffer[i], data);
+        callback(cb->buffer + i * cb->item_size, data);
         increment(cb, &i);
     } while (i != cb->head);
 }

src/lib/circular_buffer.h

@@ -53,11 +53,10 @@ void circular_buffer_push(CircularBuffer *cb, const void *item);
 bool circular_buffer_get(const CircularBuffer *cb, size_t i, void *item);
 
 /**
- * Pops an item at index i (a position relative to the current tail) from the
- * buffer. If there's no item at that index, leaves item unchanged and returns
- * false, otherwise returns true.
+ * Pops the item at the tail of the buffer. If the buffer is empty, leaves item
+ * unchanged and returns false, otherwise returns true.
  */
-bool circular_buffer_pop(CircularBuffer *cb, size_t i, void *item);
+bool circular_buffer_pop(CircularBuffer *cb, void *item);
 
 /**
  * Iterates over the buffer, calling the callback function on each item.