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

This commit is contained in:
Dean Camera 2011-07-11 05:51:35 +00:00
parent 6c4f736793
commit 87ea060afe
1 changed files with 26 additions and 8 deletions
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34
LUFA/Drivers/Misc/RingBuffer.h
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@ -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)
{