ground/openpilotgcs/src/plugins/gpsdisplay/buffer.h

   1 /**
   2  ******************************************************************************
   3  *
   4  * @file       buffer.c
   5  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
   6  * @brief      see below
   7  *             As with all modules only the initialize function is exposed all other
   8  *             interactions with the module take place through the event queue and
   9  *             objects.
  10  * @see        The GNU Public License (GPL) Version 3
  11  *
  12  *****************************************************************************/
  13
  14 /*! \file buffer.h \brief Multipurpose byte buffer structure and methods. */
  15 // *****************************************************************************
  16 //
  17 // File Name    : 'buffer.h'
  18 // Title                : Multipurpose byte buffer structure and methods
  19 // Author               : Pascal Stang - Copyright (C) 2001-2002
  20 // Created              : 9/23/2001
  21 // Revised              : 11/16/2002
  22 // Version              : 1.1
  23 // Target MCU   : any
  24 // Editor Tabs  : 4
  25 //
  26 ///     \ingroup general
  27 /// \defgroup buffer Circular Byte-Buffer Structure and Function Library (buffer.c)
  28 /// \code #include "buffer.h" \endcode
  29 /// \par Overview
  30 ///             This byte-buffer structure provides an easy and efficient way to store
  31 ///             and process a stream of bytes.  You can create as many buffers as you
  32 ///             like (within memory limits), and then use this common set of functions to
  33 ///             access each buffer.  The buffers are designed for FIFO operation (first
  34 ///             in, first out).  This means that the first byte you put in the buffer
  35 ///             will be the first one you get when you read out the buffer.  Supported
  36 ///             functions include buffer initialize, get byte from front of buffer, add
  37 ///             byte to end of buffer, check if buffer is full, and flush buffer.  The
  38 ///             buffer uses a circular design so no copying of data is ever necessary.
  39 ///             This buffer is not dynamically allocated, it has a user-defined fixed
  40 ///             maximum size.  This buffer is used in many places in the avrlib code.
  41 //
  42 // This code is distributed under the GNU Public License
  43 // which can be found at http://www.gnu.org/licenses/gpl.txt
  44 //
  45 // *****************************************************************************
  46 // @{
  47
  48 #ifndef BUFFER_HPP
  49 #define BUFFER_HPP
  50
  51 // structure/typdefs
  52
  53 // ! cBuffer structure
  54 typedef struct struct_cBuffer {
  55     unsigned char  *dataptr;                 ///< the physical memory address where the buffer is stored
  56     unsigned short size; ///< the allocated size of the buffer
  57     unsigned short datalength; ///< the length of the data currently in the buffer
  58     unsigned short dataindex; ///< the index into the buffer where the data starts
  59 } cBuffer;
  60
  61 // function prototypes
  62
  63 // ! initialize a buffer to start at a given address and have given size
  64 void                    bufferInit(cBuffer *buffer, unsigned char *start, unsigned short size);
  65
  66 // ! get the first byte from the front of the buffer
  67 unsigned char   bufferGetFromFront(cBuffer *buffer);
  68
  69 // ! dump (discard) the first numbytes from the front of the buffer
  70 void bufferDumpFromFront(cBuffer *buffer, unsigned short numbytes);
  71
  72 // ! get a byte at the specified index in the buffer (kind of like array access)
  73 // ** note: this does not remove the byte that was read from the buffer
  74 unsigned char   bufferGetAtIndex(cBuffer *buffer, unsigned short index);
  75
  76 // ! add a byte to the end of the buffer
  77 unsigned char   bufferAddToEnd(cBuffer *buffer, unsigned char data);
  78
  79 // ! check if the buffer is full/not full (returns non-zero value if not full)
  80 unsigned char   bufferIsNotFull(cBuffer *buffer);
  81
  82 // ! flush (clear) the contents of the buffer
  83 void                    bufferFlush(cBuffer *buffer);
  84
  85 #endif // ifndef BUFFER_HPP
  86 // @}