buffer: add helper function for processing wrapped buffer

Adds helper function for easier processing of wrapped buffer.
Processing modules should switch to this function instead of
directly using read and write pointers of buffer.

Signed-off-by: Tomasz Lauda <tomasz.lauda@linux.intel.com>

src/include/sof/audio/buffer.h

@@ -96,6 +96,24 @@ struct comp_buffer {
 			buffer->sink = comp;		\
 	} while (0)					\
 
+#define buffer_read_frag(buffer, idx, size) \
+	buffer_get_frag(buffer, buffer->r_ptr, idx, size)
+
+#define buffer_read_frag_s16(buffer, idx) \
+	buffer_get_frag(buffer, buffer->r_ptr, idx, sizeof(int16_t))
+
+#define buffer_read_frag_s32(buffer, idx) \
+	buffer_get_frag(buffer, buffer->r_ptr, idx, sizeof(int32_t))
+
+#define buffer_write_frag(buffer, idx, size) \
+	buffer_get_frag(buffer, buffer->w_ptr, idx, size)
+
+#define buffer_write_frag_s16(buffer, idx) \
+	buffer_get_frag(buffer, buffer->w_ptr, idx, sizeof(int16_t))
+
+#define buffer_write_frag_s32(buffer, idx) \
+	buffer_get_frag(buffer, buffer->w_ptr, idx, sizeof(int32_t))
+
 typedef void (*cache_buff_op)(struct comp_buffer *);
 
 /* pipeline buffer creation and destruction */
@@ -197,4 +215,16 @@ static inline int buffer_set_size(struct comp_buffer *buffer, uint32_t size)
 	return 0;
 }
 
+static inline void *buffer_get_frag(struct comp_buffer *buffer, void *ptr,
+				    uint32_t idx, uint32_t size)
+{
+	void *current = ptr + (idx * size);
+
+	/* check for pointer wrap */
+	if (current >= buffer->end_addr)
+		current = buffer->addr + (current - buffer->end_addr);
+
+	return current;
+}
+
 #endif