Projects/Magstripe/Lib/CircularBitBuffer.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2010  Denver Gingerich (denver [at] ossguy [dot] com)
  11   Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  12
  13   Permission to use, copy, modify, distribute, and sell this
  14   software and its documentation for any purpose is hereby granted
  15   without fee, provided that the above copyright notice appear in
  16   all copies and that both that the copyright notice and this
  17   permission notice and warranty disclaimer appear in supporting
  18   documentation, and that the name of the author not be used in
  19   advertising or publicity pertaining to distribution of the
  20   software without specific, written prior permission.
  21
  22   The author disclaim all warranties with regard to this
  23   software, including all implied warranties of merchantability
  24   and fitness.  In no event shall the author be liable for any
  25   special, indirect or consequential damages or any damages
  26   whatsoever resulting from loss of use, data or profits, whether
  27   in an action of contract, negligence or other tortious action,
  28   arising out of or in connection with the use or performance of
  29   this software.
  30 */
  31
  32 /** \file
  33  *
  34  *  Header file for CircularBitBuffer.c.
  35  */
  36
  37 #ifndef _CIRCULARBITBUFFER_H_
  38 #define _CIRCULARBITBUFFER_H_
  39
  40         /* Includes: */
  41                 #include <avr/io.h>
  42                 #include <stdbool.h>
  43
  44                 #include <LUFA/Common/Common.h>
  45
  46         /* Macros: */
  47                 #if (defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
  48                      defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__)) || defined(__DOXYGEN__)
  49                         /** Maximum number of bits which can be stored into a bit buffer. The memory usage is one eighth of this value per buffer. */
  50                         #define MAX_BITS 8192
  51                 #else
  52                         #define MAX_BITS 1024
  53                 #endif
  54
  55         /* Type Defines: */
  56                 /** Type define for a pointer to a bit in a bit buffer. */
  57                 typedef struct
  58                 {
  59                         uint8_t* CurrentByte; /**< Pointer to the current byte in the buffer */
  60                         uint8_t  ByteMask; /**< Mask of the current bit in the buffer */
  61                 } BitBufferPointer_t;
  62
  63                 /** Type define for a circular packet bit buffer. */
  64                 typedef struct
  65                 {
  66                         uint8_t            Data[MAX_BITS / 8]; /**< Buffer to hold the stored bits in packed form */
  67                         uint16_t           Elements; /**< Number of stored bits in the bit buffer */
  68
  69                         BitBufferPointer_t In; /**< Bit pointer to the next storage location in the buffer */
  70                         BitBufferPointer_t Out; /**< Bit pointer to the next retrieval location in the buffer */
  71                 } BitBuffer_t;
  72
  73         /* Function Prototypes: */
  74                 /** Initialises or resets a given bit buffer, ready to store new bits.
  75                  *
  76                  *  \param[in,out] Buffer  Bit buffer to initialize
  77                  */
  78                 void BitBuffer_Init(BitBuffer_t* const Buffer) ATTR_NON_NULL_PTR_ARG(1);
  79
  80                 /** Stores a bit into the next location inside a given bit buffer.
  81                  *
  82                  *  \param[in,out] Buffer  Bit buffer to store a bit into
  83                  *  \param[in] Bit  Bit to store into the buffer
  84                  */
  85                 void BitBuffer_StoreNextBit(BitBuffer_t* const Buffer,
  86                                             const bool Bit) ATTR_NON_NULL_PTR_ARG(1);
  87
  88                 /** Retrieves a bit from the next location inside a given bit buffer.
  89                  *
  90                  *  \param[in,out] Buffer  Bit buffer to store a bit into
  91                  *
  92                  *  \return Next bit from the buffer
  93                  */
  94                 bool BitBuffer_GetNextBit(BitBuffer_t* const Buffer) ATTR_NON_NULL_PTR_ARG(1);
  95
  96 #endif
  97