ringbuffer: fix the ambiguous name

RT_RINGBUFFER_SIZE could mean "the size of the whole buffer", "the size
of the empty space" or "the size of the data". Moreover, it's never a
micro anymore. Change it to rt_ringbuffer_data_len before it's too late.
Also, RT_RINGBUFFER_EMPTY is changed to rt_ringbuffer_space_len.

components/drivers/include/rtdevice.h

@@ -45,9 +45,9 @@ struct rt_ringbuffer
     /* use the msb of the {read,write}_index as mirror bit. You can see this as
      * if the buffer adds a virtual mirror and the pointers point either to the
      * normal or to the mirrored buffer. If the write_index has the same value
-     * with the read_index, but in differenct mirro, the buffer is full. While
-     * if the write_index and the read_index are the same and within the same
-     * mirror, the buffer is empty. The ASCII art of the ringbuffer is:
+     * with the read_index, but in a different mirror, the buffer is full.
+     * While if the write_index and the read_index are the same and within the
+     * same mirror, the buffer is empty. The ASCII art of the ringbuffer is:
      *
      *          mirror = 0                    mirror = 1
      * +---+---+---+---+---+---+---+|+~~~+~~~+~~~+~~~+~~~+~~~+~~~+
@@ -73,29 +73,6 @@ struct rt_ringbuffer
     rt_int16_t buffer_size;
 };
 
-/** return the size of data in rb */
-rt_inline rt_uint16_t RT_RINGBUFFER_SIZE(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;
-        else
-            return rb->buffer_size;
-    }
-    else
-    {
-        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 */
-#define RT_RINGBUFFER_EMPTY(rb) ((rb)->buffer_size - RT_RINGBUFFER_SIZE(rb))
-
 /* pipe device */
 #define PIPE_DEVICE(device)          ((struct rt_pipe_device*)(device))
 struct rt_pipe_device
@@ -163,12 +140,36 @@ 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);
+
 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)
+{
+    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;
+        else
+            return rb->buffer_size;
+    }
+    else
+    {
+        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 */
+#define rt_ringbuffer_space_len(rb) ((rb)->buffer_size - rt_ringbuffer_data_len(rb))
+
 /**
  * Pipe Device
  */

components/drivers/src/ringbuffer.c

@@ -53,7 +53,7 @@ rt_size_t rt_ringbuffer_put(struct rt_ringbuffer *rb,
     RT_ASSERT(rb != RT_NULL);
 
     /* whether has enough space */
-    size = RT_RINGBUFFER_EMPTY(rb);
+    size = rt_ringbuffer_space_len(rb);
 
     /* no space */
     if (size == 0)
@@ -100,7 +100,7 @@ rt_size_t rt_ringbuffer_get(struct rt_ringbuffer *rb,
     RT_ASSERT(rb != RT_NULL);
 
     /* whether has enough data  */
-    size = RT_RINGBUFFER_SIZE(rb);
+    size = rt_ringbuffer_data_len(rb);
 
     /* no data */
     if (size == 0)
@@ -143,7 +143,7 @@ rt_size_t rt_ringbuffer_putchar(struct rt_ringbuffer *rb, const rt_uint8_t ch)
     RT_ASSERT(rb != RT_NULL);
 
     /* whether has enough space */
-    if (!RT_RINGBUFFER_EMPTY(rb))
+    if (!rt_ringbuffer_space_len(rb))
         return 0;
 
     rb->buffer_ptr[rb->write_index] = ch;
@@ -171,7 +171,7 @@ rt_size_t rt_ringbuffer_getchar(struct rt_ringbuffer *rb, rt_uint8_t *ch)
     RT_ASSERT(rb != RT_NULL);
 
     /* ringbuffer is empty */
-    if (!RT_RINGBUFFER_SIZE(rb))
+    if (!rt_ringbuffer_data_len(rb))
         return 0;
 
     /* put character */

components/drivers/usb/usbdevice/class/cdc_vcom.c

@@ -188,7 +188,7 @@ static rt_err_t _ep_in_handler(udevice_t device, uclass_t cls, rt_size_t size)
 
     eps = (cdc_eps_t)cls->eps;
     level = rt_hw_interrupt_disable();
-    remain = RT_RINGBUFFER_SIZE(&tx_ringbuffer);
+    remain = rt_ringbuffer_data_len(&tx_ringbuffer);
     if (remain != 0)
     {
         /* although vcom_in_sending is set in SOF handler in the very
@@ -453,7 +453,7 @@ static rt_err_t _class_sof_handler(udevice_t device, uclass_t cls)
 
     eps = (cdc_eps_t)cls->eps;
 
-    size = RT_RINGBUFFER_SIZE(&tx_ringbuffer);
+    size = rt_ringbuffer_data_len(&tx_ringbuffer);
     if (size == 0)
         return -RT_EFULL;
 
@@ -611,7 +611,7 @@ static int _vcom_putc(struct rt_serial_device *serial, char c)
      * data out soon. But we cannot rely on that and if we wait to long, just
      * return. */
     for (cnt = 500;
-         RT_RINGBUFFER_EMPTY(&tx_ringbuffer) == 0 && cnt;
+         rt_ringbuffer_space_len(&tx_ringbuffer) == 0 && cnt;
          cnt--)
     {
         /*rt_kprintf("wait for %d\n", cnt);*/
@@ -628,7 +628,7 @@ static int _vcom_putc(struct rt_serial_device *serial, char c)
     }
 
     level = rt_hw_interrupt_disable();
-    if (RT_RINGBUFFER_EMPTY(&tx_ringbuffer))
+    if (rt_ringbuffer_space_len(&tx_ringbuffer))
     {
         rt_ringbuffer_putchar(&tx_ringbuffer, c);
     }
@@ -646,7 +646,7 @@ static int _vcom_getc(struct rt_serial_device *serial)
     result = -1;
 
     level = rt_hw_interrupt_disable();
-    if (RT_RINGBUFFER_SIZE(&rx_ringbuffer))
+    if (rt_ringbuffer_data_len(&rx_ringbuffer))
     {
         rt_ringbuffer_getchar(&rx_ringbuffer, &ch);
         result = ch;