From 4919d29d693491e8eae9697deed7b808c7bcbb93 Mon Sep 17 00:00:00 2001
From: Grissiom <chaos.proton@gmail.com>
Date: Mon, 19 Aug 2013 11:52:04 +0800
Subject: ringbuffer: add put_force and putchar_force API

Add the APIs that will discard the old data when rb is full.
---
 components/drivers/include/rtdevice.h | 38 ++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)

(limited to 'components/drivers/include/rtdevice.h')

diff --git a/components/drivers/include/rtdevice.h b/components/drivers/include/rtdevice.h
index a941b22131..bd6e243b0a 100644
--- a/components/drivers/include/rtdevice.h
+++ b/components/drivers/include/rtdevice.h
@@ -134,37 +134,61 @@ void rt_ringbuffer_init(struct rt_ringbuffer *rb,
 rt_size_t rt_ringbuffer_put(struct rt_ringbuffer *rb,
                             const rt_uint8_t     *ptr,
                             rt_uint16_t           length);
+rt_size_t rt_ringbuffer_put_force(struct rt_ringbuffer *rb,
+                                  const rt_uint8_t     *ptr,
+                                  rt_uint16_t           length);
 rt_size_t rt_ringbuffer_putchar(struct rt_ringbuffer *rb,
                                 const rt_uint8_t      ch);
+rt_size_t rt_ringbuffer_putchar_force(struct rt_ringbuffer *rb,
+                                      const rt_uint8_t      ch);
 rt_size_t rt_ringbuffer_get(struct rt_ringbuffer *rb,
                             rt_uint8_t           *ptr,
                             rt_uint16_t           length);
 rt_size_t rt_ringbuffer_getchar(struct rt_ringbuffer *rb, rt_uint8_t *ch);
 
+enum rt_ringbuffer_state
+{
+    RT_RINGBUFFER_EMPTY,
+    RT_RINGBUFFER_FULL,
+    /* half full is neither full nor empty */
+    RT_RINGBUFFER_HALFFULL,
+};
+
 rt_inline rt_uint16_t rt_ringbuffer_get_size(struct rt_ringbuffer *rb)
 {
     RT_ASSERT(rb != RT_NULL);
     return rb->buffer_size;
 }
 
-/** return the size of data in rb */
-rt_inline rt_uint16_t rt_ringbuffer_data_len(struct rt_ringbuffer *rb)
+rt_inline enum rt_ringbuffer_state
+rt_ringbuffer_status(struct rt_ringbuffer *rb)
 {
     if (rb->read_index == rb->write_index)
     {
         if (rb->read_mirror == rb->write_mirror)
-            /* we are in the same side, the ringbuffer is empty. */
-            return 0;
+            return RT_RINGBUFFER_EMPTY;
         else
-            return rb->buffer_size;
+            return RT_RINGBUFFER_FULL;
     }
-    else
+    return RT_RINGBUFFER_HALFFULL;
+}
+
+/** return the size of data in rb */
+rt_inline rt_uint16_t rt_ringbuffer_data_len(struct rt_ringbuffer *rb)
+{
+    switch (rt_ringbuffer_status(rb))
     {
+    case RT_RINGBUFFER_EMPTY:
+        return 0;
+    case RT_RINGBUFFER_FULL:
+        return rb->buffer_size;
+    case RT_RINGBUFFER_HALFFULL:
+    default:
         if (rb->write_index > rb->read_index)
             return rb->write_index - rb->read_index;
         else
             return rb->buffer_size - (rb->read_index - rb->write_index);
-    }
+    };
 }
 
 /** return the size of empty space in rb */
-- 
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