Added new RingBuffer_GetFreeCount() function to the library miscellaneous RingBuffer driver.

1 files changed, 26 insertions, 8 deletions

diff --git a/LUFA/Drivers/Misc/RingBuffer.h b/LUFA/Drivers/Misc/RingBuffer.h
index c95363871..937cb4abf 100644
--- a/LUFA/Drivers/Misc/RingBuffer.h
+++ b/LUFA/Drivers/Misc/RingBuffer.h
@@ -29,7 +29,7 @@
 */

 

 /** \file

- *  \brief Lightweight ring buffer, for fast insertion/deletion of bytes.

+ *  \brief Lightweight ring (circular) buffer, for fast insertion/deletion of bytes.

  *

  *  Lightweight ring buffer, for fast insertion/deletion. Multiple buffers can be created of

  *  different sizes to suit different needs.

@@ -126,7 +126,7 @@
 		 *  \param[out] DataPtr  Pointer to a global array that will hold the data stored into the ring buffer.

 		 *  \param[out] Size     Maximum number of bytes that can be stored in the underlying data array.

 		 */

-		static inline void RingBuffer_InitBuffer(RingBuffer_t* Buffer, uint8_t* const DataPtr, const uint16_t Size)

+		static inline void RingBuffer_InitBuffer(RingBuffer_t* const Buffer, uint8_t* const DataPtr, const uint16_t Size)

 		{

 			GCC_FORCE_POINTER_ACCESS(Buffer);

 

@@ -143,18 +143,36 @@
 			SetGlobalInterruptMask(CurrentGlobalInt);

 		}

 

-		/** Retrieves the minimum number of bytes stored in a particular buffer. This value is computed

-		 *  by entering an atomic lock on the buffer while the IN and OUT locations are fetched, so that

-		 *  the buffer cannot be modified while the computation takes place. This value should be cached

-		 *  when reading out the contents of the buffer, so that as small a time as possible is spent

-		 *  in an atomic lock.

+		/** Retrieves the free space in a particular buffer. This value is computed by entering an atomic lock

+		 *  on the buffer, so that the buffer cannot be modified while the computation takes place.

+		 *

+		 *  \note The value returned by this function is guaranteed to only be the maximum number of bytes

+		 *        free in the given buffer; this value may change as other threads write new data, thus

+		 *        the returned number should be used only to determine how many successive writes may safely

+		 *        be performed on the buffer when there is a single writer thread.

+		 *

+		 *  \param[in] Buffer  Pointer to a ring buffer structure whose free count is to be computed.

+		 *

+		 *  \return Number of free bytes in the buffer.

+		 */

+		static inline uint16_t RingBuffer_GetFreeCount(RingBuffer_t* const Buffer)

+		{

+			return (Buffer->Size - RingBuffer_GetCount(Buffer));

+		}

+

+		/** Retrieves the current number of bytes stored in a particular buffer. This value is computed

+		 *  by entering an atomic lock on the buffer, so that the buffer cannot be modified while the

+		 *  computation takes place. This value should be cached when reading out the contents of the buffer,

+		 *  so that as small a time as possible is spent in an atomic lock.

 		 *

 		 *  \note The value returned by this function is guaranteed to only be the minimum number of bytes

-		 *        stored in the given buffer; this value may change as other threads write new data and so

+		 *        stored in the given buffer; this value may change as other threads write new data, thus

 		 *        the returned number should be used only to determine how many successive reads may safely

 		 *        be performed on the buffer.

 		 *

 		 *  \param[in] Buffer  Pointer to a ring buffer structure whose count is to be computed.

+		 *

+		 *  \return Number of bytes currently stored in the buffer.

 		 */

 		static inline uint16_t RingBuffer_GetCount(RingBuffer_t* const Buffer)

 		{