buffer.h

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/*! \file buffer.h \brief Multipurpose byte buffer structure and methods. */
//*****************************************************************************
//
// File Name    : 'buffer.h'
// Title        : Multipurpose byte buffer structure and methods
// Author       : Pascal Stang - Copyright (C) 2001-2002
// Created      : 9/23/2001
// Revised      : 11/16/2002
// Version      : 1.1
// Target MCU   : any
// Editor Tabs  : 4
//
/// \ingroup general
/// \defgroup buffer Circular Byte-Buffer Structure and Function Library (buffer.c)
/// \code #include "buffer.h" \endcode
/// \par Overview
///     This byte-buffer structure provides an easy and efficient way to store
///     and process a stream of bytes.  You can create as many buffers as you
///     like (within memory limits), and then use this common set of functions to
///     access each buffer.  The buffers are designed for FIFO operation (first
///     in, first out).  This means that the first byte you put in the buffer
///     will be the first one you get when you read out the buffer.  Supported
///     functions include buffer initialize, get byte from front of buffer, add
///     byte to end of buffer, check if buffer is full, and flush buffer.  The
///     buffer uses a circular design so no copying of data is ever necessary.
///     This buffer is not dynamically allocated, it has a user-defined fixed
///     maximum size.  This buffer is used in many places in the avrlib code.
//
// This code is distributed under the GNU Public License
//      which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
//@{

#ifndef BUFFER_H
#define BUFFER_H

// structure/typdefs

//! cBuffer structure
typedef struct struct_cBuffer
{
    unsigned char *dataptr;         ///< the physical memory address where the buffer is stored
    unsigned short size;            ///< the allocated size of the buffer
    unsigned short datalength;      ///< the length of the data currently in the buffer
    unsigned short dataindex;       ///< the index into the buffer where the data starts
} cBuffer;

// function prototypes

//! initialize a buffer to start at a given address and have given size
void            bufferInit(cBuffer* buffer, unsigned char *start, unsigned short size);

//! get the first byte from the front of the buffer
unsigned char   bufferGetFromFront(cBuffer* buffer);

//! dump (discard) the first numbytes from the front of the buffer
void bufferDumpFromFront(cBuffer* buffer, unsigned short numbytes);

//! get a byte at the specified index in the buffer (kind of like array access)
// ** note: this does not remove the byte that was read from the buffer
unsigned char   bufferGetAtIndex(cBuffer* buffer, unsigned short index);

//! add a byte to the end of the buffer
unsigned char   bufferAddToEnd(cBuffer* buffer, unsigned char data);

//! check if the buffer is full/not full (returns zero value if full)
unsigned short  bufferIsNotFull(cBuffer* buffer);

//! flush (clear) the contents of the buffer
void            bufferFlush(cBuffer* buffer);

#endif
//@}

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