From 6225a8596005bfb0be68fa641f5b47d01a95c12d Mon Sep 17 00:00:00 2001 From: "David A. Mellis" Date: Thu, 13 Sep 2012 10:39:59 -0400 Subject: Moving ATmegaXXU2 firmwares into subdirectory. --- .../arduino-usbserial/Lib/LightweightRingBuff.h | 197 +++++++++++++++++++++ 1 file changed, 197 insertions(+) create mode 100755 firmwares/atmegaxxu2/arduino-usbserial/Lib/LightweightRingBuff.h (limited to 'firmwares/atmegaxxu2/arduino-usbserial/Lib/LightweightRingBuff.h') diff --git a/firmwares/atmegaxxu2/arduino-usbserial/Lib/LightweightRingBuff.h b/firmwares/atmegaxxu2/arduino-usbserial/Lib/LightweightRingBuff.h new file mode 100755 index 0000000..fb48c1f --- /dev/null +++ b/firmwares/atmegaxxu2/arduino-usbserial/Lib/LightweightRingBuff.h @@ -0,0 +1,197 @@ +/* + LUFA Library + Copyright (C) Dean Camera, 2010. + + dean [at] fourwalledcubicle [dot] com + www.fourwalledcubicle.com +*/ + +/* + Copyright 2010 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 + * + * Ultra lightweight ring buffer, for fast insertion/deletion. + */ + +#ifndef _ULW_RING_BUFF_H_ +#define _ULW_RING_BUFF_H_ + + /* Includes: */ + #include + + #include + #include + + /* Defines: */ + /** Size of each ring buffer, in data elements - must be between 1 and 255. */ + #define BUFFER_SIZE 128 + + /** Maximum number of data elements to buffer before forcing a flush. + * Must be less than BUFFER_SIZE + */ + #define BUFFER_NEARLY_FULL 96 + + /** Type of data to store into the buffer. */ + #define RingBuff_Data_t uint8_t + + /** Datatype which may be used to store the count of data stored in a buffer, retrieved + * via a call to \ref RingBuffer_GetCount(). + */ + #if (BUFFER_SIZE <= 0xFF) + #define RingBuff_Count_t uint8_t + #else + #define RingBuff_Count_t uint16_t + #endif + + /* Type Defines: */ + /** Type define for a new ring buffer object. Buffers should be initialized via a call to + * \ref RingBuffer_InitBuffer() before use. + */ + typedef struct + { + RingBuff_Data_t Buffer[BUFFER_SIZE]; /**< Internal ring buffer data, referenced by the buffer pointers. */ + RingBuff_Data_t* In; /**< Current storage location in the circular buffer */ + RingBuff_Data_t* Out; /**< Current retrieval location in the circular buffer */ + RingBuff_Count_t Count; + } RingBuff_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 + */ + static inline void RingBuffer_InitBuffer(RingBuff_t* const Buffer) + { + ATOMIC_BLOCK(ATOMIC_RESTORESTATE) + { + Buffer->In = Buffer->Buffer; + Buffer->Out = Buffer->Buffer; + } + } + + /** 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. + * + * \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 + * 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 + */ + static inline RingBuff_Count_t RingBuffer_GetCount(RingBuff_t* const Buffer) + { + RingBuff_Count_t Count; + + ATOMIC_BLOCK(ATOMIC_RESTORESTATE) + { + Count = Buffer->Count; + } + + return Count; + } + + /** 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 true if the buffer contains no free space, false otherwise + */ + static inline bool RingBuffer_IsFull(RingBuff_t* const Buffer) + { + return (RingBuffer_GetCount(Buffer) == BUFFER_SIZE); + } + + /** 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 true if the buffer contains no free space, false otherwise + */ + static inline bool RingBuffer_IsEmpty(RingBuff_t* const Buffer) + { + return (RingBuffer_GetCount(Buffer) == 0); + } + + /** Inserts an element into the ring buffer. + * + * \note 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(RingBuff_t* const Buffer, + const RingBuff_Data_t Data) + { + *Buffer->In = Data; + + if (++Buffer->In == &Buffer->Buffer[BUFFER_SIZE]) + Buffer->In = Buffer->Buffer; + + ATOMIC_BLOCK(ATOMIC_RESTORESTATE) + { + Buffer->Count++; + } + } + + /** Removes an element from the ring buffer. + * + * \note 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 RingBuff_Data_t RingBuffer_Remove(RingBuff_t* const Buffer) + { + RingBuff_Data_t Data = *Buffer->Out; + + if (++Buffer->Out == &Buffer->Buffer[BUFFER_SIZE]) + Buffer->Out = Buffer->Buffer; + + ATOMIC_BLOCK(ATOMIC_RESTORESTATE) + { + Buffer->Count--; + } + + return Data; + } + +#endif -- cgit v1.2.3-18-g5258