309 lines
12 KiB
C
309 lines
12 KiB
C
/*
|
|
LUFA Library
|
|
Copyright (C) Dean Camera, 2017.
|
|
|
|
dean [at] fourwalledcubicle [dot] com
|
|
www.lufa-lib.org
|
|
*/
|
|
|
|
/*
|
|
Copyright 2017 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 disclaims 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_RingBuff_Dependencies Module Source Dependencies
|
|
* The following files must be built with any user project that uses this module:
|
|
* - None
|
|
*
|
|
* \section Sec_RingBuff_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_RingBuff_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, \c 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, \c 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
|
|
|
|
/** @} */
|
|
|