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Diffstat (limited to 'protocol/lufa/LUFA-120730/LUFA/Drivers/Misc/RingBuffer.h')
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1 files changed, 303 insertions, 0 deletions
diff --git a/protocol/lufa/LUFA-120730/LUFA/Drivers/Misc/RingBuffer.h b/protocol/lufa/LUFA-120730/LUFA/Drivers/Misc/RingBuffer.h new file mode 100644 index 0000000000..6d0f60ffa8 --- /dev/null +++ b/protocol/lufa/LUFA-120730/LUFA/Drivers/Misc/RingBuffer.h @@ -0,0 +1,303 @@ +/*
+ LUFA Library
+ Copyright (C) Dean Camera, 2012.
+
+ dean [at] fourwalledcubicle [dot] com
+ www.lufa-lib.org
+*/
+
+/*
+ Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
+
+ Permission to use, copy, modify, distribute, and sell this
+ software and its documentation for any purpose is hereby granted
+ without fee, provided that the above copyright notice appear in
+ all copies and that both that the copyright notice and this
+ permission notice and warranty disclaimer appear in supporting
+ documentation, and that the name of the author not be used in
+ advertising or publicity pertaining to distribution of the
+ software without specific, written prior permission.
+
+ The author disclaim all warranties with regard to this
+ software, including all implied warranties of merchantability
+ and fitness. In no event shall the author be liable for any
+ special, indirect or consequential damages or any damages
+ whatsoever resulting from loss of use, data or profits, whether
+ in an action of contract, negligence or other tortious action,
+ arising out of or in connection with the use or performance of
+ this software.
+*/
+
+/** \file
+ * \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.
+ *
+ * Note that for each buffer, insertion and removal operations may occur at the same time (via
+ * a multi-threaded ISR based system) however the same kind of operation (two or more insertions
+ * or deletions) must not overlap. If there is possibility of two or more of the same kind of
+ * operating occurring at the same point in time, atomic (mutex) locking should be used.
+ */
+
+/** \ingroup Group_MiscDrivers
+ * \defgroup Group_RingBuff Generic Byte Ring Buffer - LUFA/Drivers/Misc/RingBuffer.h
+ * \brief Lightweight ring buffer, for fast insertion/deletion of bytes.
+ *
+ * \section Sec_Dependencies Module Source Dependencies
+ * The following files must be built with any user project that uses this module:
+ * - None
+ *
+ * \section Sec_ModDescription Module Description
+ * Lightweight ring buffer, for fast insertion/deletion. Multiple buffers can be created of
+ * different sizes to suit different needs.
+ *
+ * Note that for each buffer, insertion and removal operations may occur at the same time (via
+ * a multi-threaded ISR based system) however the same kind of operation (two or more insertions
+ * or deletions) must not overlap. If there is possibility of two or more of the same kind of
+ * operating occurring at the same point in time, atomic (mutex) locking should be used.
+ *
+ * \section Sec_ExampleUsage Example Usage
+ * The following snippet is an example of how this module may be used within a typical
+ * application.
+ *
+ * \code
+ * // Create the buffer structure and its underlying storage array
+ * RingBuffer_t Buffer;
+ * uint8_t BufferData[128];
+ *
+ * // Initialize the buffer with the created storage array
+ * RingBuffer_InitBuffer(&Buffer, BufferData, sizeof(BufferData));
+ *
+ * // Insert some data into the buffer
+ * RingBuffer_Insert(Buffer, 'H');
+ * RingBuffer_Insert(Buffer, 'E');
+ * RingBuffer_Insert(Buffer, 'L');
+ * RingBuffer_Insert(Buffer, 'L');
+ * RingBuffer_Insert(Buffer, 'O');
+ *
+ * // Cache the number of stored bytes in the buffer
+ * uint16_t BufferCount = RingBuffer_GetCount(&Buffer);
+ *
+ * // Printer stored data length
+ * printf("Buffer Length: %d, Buffer Data: \r\n", BufferCount);
+ *
+ * // Print contents of the buffer one character at a time
+ * while (BufferCount--)
+ * putc(RingBuffer_Remove(&Buffer));
+ * \endcode
+ *
+ * @{
+ */
+
+#ifndef __RING_BUFFER_H__
+#define __RING_BUFFER_H__
+
+ /* Includes: */
+ #include "../../Common/Common.h"
+
+ /* Enable C linkage for C++ Compilers: */
+ #if defined(__cplusplus)
+ extern "C" {
+ #endif
+
+ /* Type Defines: */
+ /** \brief Ring Buffer Management Structure.
+ *
+ * Type define for a new ring buffer object. Buffers should be initialized via a call to
+ * \ref RingBuffer_InitBuffer() before use.
+ */
+ typedef struct
+ {
+ uint8_t* In; /**< Current storage location in the circular buffer. */
+ uint8_t* Out; /**< Current retrieval location in the circular buffer. */
+ uint8_t* Start; /**< Pointer to the start of the buffer's underlying storage array. */
+ uint8_t* End; /**< Pointer to the end of the buffer's underlying storage array. */
+ uint16_t Size; /**< Size of the buffer's underlying storage array. */
+ uint16_t Count; /**< Number of bytes currently stored in the buffer. */
+ } RingBuffer_t;
+
+ /* Inline Functions: */
+ /** Initializes a ring buffer ready for use. Buffers must be initialized via this function
+ * before any operations are called upon them. Already initialized buffers may be reset
+ * by re-initializing them using this function.
+ *
+ * \param[out] Buffer Pointer to a ring buffer structure to initialize.
+ * \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)
+ ATTR_NON_NULL_PTR_ARG(1) ATTR_NON_NULL_PTR_ARG(2);
+ static inline void RingBuffer_InitBuffer(RingBuffer_t* Buffer, uint8_t* const DataPtr, const uint16_t Size)
+ {
+ GCC_FORCE_POINTER_ACCESS(Buffer);
+
+ uint_reg_t CurrentGlobalInt = GetGlobalInterruptMask();
+ GlobalInterruptDisable();
+
+ Buffer->In = DataPtr;
+ Buffer->Out = DataPtr;
+ Buffer->Start = &DataPtr[0];
+ Buffer->End = &DataPtr[Size];
+ Buffer->Size = Size;
+ Buffer->Count = 0;
+
+ SetGlobalInterruptMask(CurrentGlobalInt);
+ }
+
+ /** 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, 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) ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+ static inline uint16_t RingBuffer_GetCount(RingBuffer_t* const Buffer)
+ {
+ uint16_t Count;
+
+ uint_reg_t CurrentGlobalInt = GetGlobalInterruptMask();
+ GlobalInterruptDisable();
+
+ Count = Buffer->Count;
+
+ SetGlobalInterruptMask(CurrentGlobalInt);
+ return Count;
+ }
+
+ /** 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) ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+ static inline uint16_t RingBuffer_GetFreeCount(RingBuffer_t* const Buffer)
+ {
+ return (Buffer->Size - RingBuffer_GetCount(Buffer));
+ }
+
+ /** Atomically determines if the specified ring buffer contains any data. This should
+ * be tested before removing data from the buffer, to ensure that the buffer does not
+ * underflow.
+ *
+ * If the data is to be removed in a loop, store the total number of bytes stored in the
+ * buffer (via a call to the \ref RingBuffer_GetCount() function) in a temporary variable
+ * to reduce the time spent in atomicity locks.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to insert into.
+ *
+ * \return Boolean \c true if the buffer contains no free space, false otherwise.
+ */
+ static inline bool RingBuffer_IsEmpty(RingBuffer_t* const Buffer) ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+ static inline bool RingBuffer_IsEmpty(RingBuffer_t* const Buffer)
+ {
+ return (RingBuffer_GetCount(Buffer) == 0);
+ }
+
+ /** Atomically determines if the specified ring buffer contains any free space. This should
+ * be tested before storing data to the buffer, to ensure that no data is lost due to a
+ * buffer overrun.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to insert into.
+ *
+ * \return Boolean \c true if the buffer contains no free space, false otherwise.
+ */
+ static inline bool RingBuffer_IsFull(RingBuffer_t* const Buffer) ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+ static inline bool RingBuffer_IsFull(RingBuffer_t* const Buffer)
+ {
+ return (RingBuffer_GetCount(Buffer) == Buffer->Size);
+ }
+
+ /** Inserts an element into the ring buffer.
+ *
+ * \warning Only one execution thread (main program thread or an ISR) may insert into a single buffer
+ * otherwise data corruption may occur. Insertion and removal may occur from different execution
+ * threads.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to insert into.
+ * \param[in] Data Data element to insert into the buffer.
+ */
+ static inline void RingBuffer_Insert(RingBuffer_t* Buffer, const uint8_t Data) ATTR_NON_NULL_PTR_ARG(1);
+ static inline void RingBuffer_Insert(RingBuffer_t* Buffer, const uint8_t Data)
+ {
+ GCC_FORCE_POINTER_ACCESS(Buffer);
+
+ *Buffer->In = Data;
+
+ if (++Buffer->In == Buffer->End)
+ Buffer->In = Buffer->Start;
+
+ uint_reg_t CurrentGlobalInt = GetGlobalInterruptMask();
+ GlobalInterruptDisable();
+
+ Buffer->Count++;
+
+ SetGlobalInterruptMask(CurrentGlobalInt);
+ }
+
+ /** Removes an element from the ring buffer.
+ *
+ * \warning Only one execution thread (main program thread or an ISR) may remove from a single buffer
+ * otherwise data corruption may occur. Insertion and removal may occur from different execution
+ * threads.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to retrieve from.
+ *
+ * \return Next data element stored in the buffer.
+ */
+ static inline uint8_t RingBuffer_Remove(RingBuffer_t* Buffer) ATTR_NON_NULL_PTR_ARG(1);
+ static inline uint8_t RingBuffer_Remove(RingBuffer_t* Buffer)
+ {
+ GCC_FORCE_POINTER_ACCESS(Buffer);
+
+ uint8_t Data = *Buffer->Out;
+
+ if (++Buffer->Out == Buffer->End)
+ Buffer->Out = Buffer->Start;
+
+ uint_reg_t CurrentGlobalInt = GetGlobalInterruptMask();
+ GlobalInterruptDisable();
+
+ Buffer->Count--;
+
+ SetGlobalInterruptMask(CurrentGlobalInt);
+
+ return Data;
+ }
+
+ /** Returns the next element stored in the ring buffer, without removing it.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to retrieve from.
+ *
+ * \return Next data element stored in the buffer.
+ */
+ static inline uint8_t RingBuffer_Peek(RingBuffer_t* const Buffer) ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+ static inline uint8_t RingBuffer_Peek(RingBuffer_t* const Buffer)
+ {
+ return *Buffer->Out;
+ }
+
+ /* Disable C linkage for C++ Compilers: */
+ #if defined(__cplusplus)
+ }
+ #endif
+
+#endif
+
+/** @} */
+
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