/*
             LUFA Library
     Copyright (C) Dean Camera, 2009.
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
  Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, and distribute this software
  and its documentation for any purpose and without fee is hereby
  granted, 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.
*/

/* Buffer Configuration: */
   /* Buffer length - select static size of created ring buffers: */
	 #define BUFF_STATICSIZE 128      // Set to the static ring buffer size for all ring buffers (place size after define)

   /* Volatile mode - uncomment to make buffers volatile, for use in ISRs, etc: */
	 #define BUFF_VOLATILE            // Uncomment to cause all ring buffers to become volatile (and atomic if multi-byte) in access

   /* Drop mode - select behaviour when Buffer_StoreElement called on a full buffer: */
     #define BUFF_DROPOLD             // Uncomment to cause full ring buffers to drop the oldest character to make space when full
     // #define BUFF_DROPNEW          // Uncomment to cause full ring buffers to drop the new character when full
     // #define BUFF_NODROPCHECK      // Uncomment to ignore full ring buffer checks - checking left to user!

   /* Underflow behaviour - select behaviour when Buffer_GetElement is called with an empty ring buffer: */
     //#define BUFF_EMPTYRETURNSZERO  // Uncomment to return 0 when an empty ring buffer is read
     #define BUFF_NOEMPTYCHECK        // Uncomment to disable checking of empty ring buffers - checking left to user!
	
   /* Buffer storage type - set the datatype for the stored data */
     #define BUFF_DATATYPE uint8_t    // Change to the data type that is going to be stored into the buffer
	
   /* Peek routine - uncomment to include the peek routine (fetches next byte without removing it from the buffer */
     //#define BUFF_USEPEEK
	 	
#ifndef _RINGBUFF_H_
#define _RINGBUFF_H_

	/* Includes: */
	#include <avr/io.h>
	#include <avr/interrupt.h>
	#include <util/atomic.h>
	#include <limits.h>

	#include <LUFA/Common/Common.h>

	/* Defines and checks: */
	#if defined(BUFF_STATICSIZE)
		#define BUFF_LENGTH BUFF_STATICSIZE
	#else
		#error No buffer length specified!
	#endif

	#if !(defined(BUFF_DROPOLD) || defined(BUFF_DROPNEW) || defined(BUFF_NODROPCHECK))
		#error No buffer drop mode specified.
	#endif

	#if !defined(BUFF_DATATYPE)
		#error Ringbuffer storage data type not specified.
	#endif

	#if defined(BUFF_VOLATILE)
		#define BUFF_MODE            volatile
		#define BUFF_ATOMIC_BLOCK    ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
	#else
		#define BUFF_MODE
		#define BUFF_ATOMIC_BLOCK
	#endif

	#if (BUFF_STATICSIZE   > LONG_MAX)
		#define RingBuff_Elements_t uint64_t
	#elif (BUFF_STATICSIZE > INT_MAX)
		#define RingBuff_Elements_t uint32_t
	#elif (BUFF_STATICSIZE > CHAR_MAX)
		#define RingBuff_Elements_t uint16_t
	#else
		#define RingBuff_Elements_t uint8_t
	#endif
	
	/* Type Defines: */
	typedef BUFF_DATATYPE RingBuff_Data_t;

	typedef BUFF_MODE struct
	{
		RingBuff_Data_t      Buffer[BUFF_LENGTH];
		RingBuff_Data_t*     InPtr;
		RingBuff_Data_t*     OutPtr;
		RingBuff_Elements_t  Elements;
	} RingBuff_t;
		
	/* Function Prototypes: */
	void            Buffer_Initialize(RingBuff_t* Buff);
	void            Buffer_StoreElement(RingBuff_t* Buffer, RingBuff_Data_t Data);
	RingBuff_Data_t Buffer_GetElement(RingBuff_t* Buffer);
	#if defined(BUFF_USEPEEK)
		RingBuff_Data_t Buffer_PeekElement(const RingBuff_t* Buffer);
	#endif
	
#endif
