ring_buffer: simplify code some more

Some variable renaming made the code clearer, which in turn allowed for
minor optimizations.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>

Author: Nicolas Pitre

lib/utils/ring_buffer.c

@@ -12,20 +12,17 @@
 uint32_t ring_buf_area_claim(struct ring_buf *buf, struct ring_buf_index *ring,
 			     uint8_t **data, uint32_t size)
 {
-	uint32_t wrap_size;
-	int32_t base;
+	uint32_t head_offset, wrap_size;
 
-	base = ring->base;
-	wrap_size = ring->head - base;
-	if (unlikely(wrap_size >= buf->size)) {
+	head_offset = ring->head - ring->base;
+	if (unlikely(head_offset >= buf->size)) {
 		/* ring->base is not yet adjusted */
-		wrap_size -= buf->size;
-		base += buf->size;
+		head_offset -= buf->size;
 	}
-	wrap_size = buf->size - wrap_size;
+	wrap_size = buf->size - head_offset;
 	size = MIN(size, wrap_size);
 
-	*data = &buf->buffer[ring->head - base];
+	*data = &buf->buffer[head_offset];
 	ring->head += size;
 
 	return size;
@@ -34,7 +31,7 @@ uint32_t ring_buf_area_claim(struct ring_buf *buf, struct ring_buf_index *ring,
 int ring_buf_area_finish(struct ring_buf *buf, struct ring_buf_index *ring,
 			 uint32_t size)
 {
-	uint32_t claimed_size, wrap_size;
+	uint32_t claimed_size, tail_offset;
 
 	claimed_size = ring->head - ring->tail;
 	if (unlikely(size > claimed_size)) {
@@ -44,8 +41,8 @@ int ring_buf_area_finish(struct ring_buf *buf, struct ring_buf_index *ring,
 	ring->tail += size;
 	ring->head = ring->tail;
 
-	wrap_size = ring->tail - ring->base;
-	if (unlikely(wrap_size >= buf->size)) {
+	tail_offset = ring->tail - ring->base;
+	if (unlikely(tail_offset >= buf->size)) {
 		/* we wrapped: adjust ring->base */
 		ring->base += buf->size;
 	}