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# buffer.h

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    00001 /*! \file buffer.h \brief Multipurpose byte buffer structure and methods. */
    00002 //*****************************************************************************
    00003 //
    00004 // File Name    : 'buffer.h'
    00005 // Title        : Multipurpose byte buffer structure and methods
    00006 // Author       : Pascal Stang - Copyright (C) 2001-2002
    00007 // Created      : 9/23/2001
    00008 // Revised      : 11/16/2002
    00009 // Version      : 1.1
    00010 // Target MCU   : any
    00011 // Editor Tabs  : 4
    00012 //
    00013 /// \ingroup general
    00014 /// \defgroup buffer Circular Byte-Buffer Structure and Function Library (buffer.c)
    00015 /// \code #include "buffer.h" \endcode
    00016 /// \par Overview
    00017 ///     This byte-buffer structure provides an easy and efficient way to store
    00018 ///     and process a stream of bytes.  You can create as many buffers as you
    00019 ///     like (within memory limits), and then use this common set of functions to
    00020 ///     access each buffer.  The buffers are designed for FIFO operation (first
    00021 ///     in, first out).  This means that the first byte you put in the buffer
    00022 ///     will be the first one you get when you read out the buffer.  Supported
    00023 ///     functions include buffer initialize, get byte from front of buffer, add
    00024 ///     byte to end of buffer, check if buffer is full, and flush buffer.  The
    00025 ///     buffer uses a circular design so no copying of data is ever necessary.
    00026 ///     This buffer is not dynamically allocated, it has a user-defined fixed
    00027 ///     maximum size.  This buffer is used in many places in the avrlib code.
    00028 //
    00029 // This code is distributed under the GNU Public License
    00030 //      which can be found at http://www.gnu.org/licenses/gpl.txt
    00031 //
    00032 //*****************************************************************************
    00033 //@{
    00034
    00035 #ifndef BUFFER_H
    00036 #define BUFFER_H
    00037
    00038 // structure/typdefs
    00039
    00040 // the cBuffer structure
    00041 typedef struct struct_cBuffer
    00042 {
    00043     unsigned char *dataptr;         // the physical memory address where the buffer is stored
    00044     unsigned short size;            // the allocated size of the buffer
    00045     unsigned short datalength;      // the length of the data currently in the buffer
    00046     unsigned short dataindex;       // the index into the buffer where the data starts
    00047 } cBuffer;
    00048
    00049 // function prototypes
    00050
    00051 //! initialize a buffer to start at a given address and have given size
    00052 void            bufferInit(cBuffer* buffer, unsigned char *start, unsigned short size);
    00053
    00054 //! get the first byte from the front of the buffer
    00055 unsigned char   bufferGetFromFront(cBuffer* buffer);
    00056
    00057 //! dump (discard) the first numbytes from the front of the buffer
    00058 void bufferDumpFromFront(cBuffer* buffer, unsigned short numbytes);
    00059
    00060 //! get a byte at the specified index in the buffer (kind of like array access)
    00061 // ** note: this does not remove the byte that was read from the buffer
    00062 unsigned char   bufferGetAtIndex(cBuffer* buffer, unsigned short index);
    00063
    00064 //! add a byte to the end of the buffer
    00065 unsigned char   bufferAddToEnd(cBuffer* buffer, unsigned char data);
    00066
    00067 //! check if the buffer is full/not full (returns zero value if full)
    00068 unsigned short  bufferIsNotFull(cBuffer* buffer);
    00069
    00070 //! flush (clear) the contents of the buffer
    00071 void            bufferFlush(cBuffer* buffer);
    00072
    00073 #endif
    00074 //@}