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LibrePilot/flight/OpenPilot/Modules/GPS/buffer.c
peabody124 d928676f5e More documentation updates, standardizing format to include addtogroup at the beginning of headers so files are associated with modules
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1121 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-07-16 19:53:35 +00:00

149 lines
4.1 KiB
C

/**
******************************************************************************
*
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup GSPModule GPS Module
* @brief Process GPS information
* @{
*
* @file buffer.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief
* As with all modules only the initialize function is exposed all other
* interactions with the module take place through the event queue and
* objects.
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
//*****************************************************************************
//
// File Name : 'buffer.c'
// Title : Multipurpose byte buffer structure and methods
// Author : Pascal Stang - Copyright (C) 2001-2002
// Created : 9/23/2001
// Revised : 9/23/2001
// Version : 1.0
// Target MCU : any
// Editor Tabs : 4
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
#include "buffer.h"
// global variables
// initialization
void bufferInit(cBuffer* buffer, unsigned char *start, unsigned short size)
{
// set start pointer of the buffer
buffer->dataptr = start;
buffer->size = size;
// initialize index and length
buffer->dataindex = 0;
buffer->datalength = 0;
}
// access routines
unsigned char bufferGetFromFront(cBuffer* buffer)
{
unsigned char data = 0;
// check to see if there's data in the buffer
if(buffer->datalength)
{
// get the first character from buffer
data = buffer->dataptr[buffer->dataindex];
// move index down and decrement length
buffer->dataindex++;
if(buffer->dataindex >= buffer->size)
{
buffer->dataindex %= buffer->size;
}
buffer->datalength--;
}
// return
return data;
}
void bufferDumpFromFront(cBuffer* buffer, unsigned short numbytes)
{
// dump numbytes from the front of the buffer
// are we dumping less than the entire buffer?
if(numbytes < buffer->datalength)
{
// move index down by numbytes and decrement length by numbytes
buffer->dataindex += numbytes;
if(buffer->dataindex >= buffer->size)
{
buffer->dataindex %= buffer->size;
}
buffer->datalength -= numbytes;
}
else
{
// flush the whole buffer
buffer->datalength = 0;
}
}
unsigned char bufferGetAtIndex(cBuffer* buffer, unsigned short index)
{
// return character at index in buffer
return buffer->dataptr[(buffer->dataindex+index)%(buffer->size)];
}
unsigned char bufferAddToEnd(cBuffer* buffer, unsigned char data)
{
// make sure the buffer has room
if(buffer->datalength < buffer->size)
{
// save data byte at end of buffer
buffer->dataptr[(buffer->dataindex + buffer->datalength) % buffer->size] = data;
// increment the length
buffer->datalength++;
// return success
return -1;
}
else return 0;
}
unsigned char bufferIsNotFull(cBuffer* buffer)
{
// check to see if the buffer has room
// return true if there is room
return (buffer->datalength < buffer->size);
}
void bufferFlush(cBuffer* buffer)
{
// flush contents of the buffer
buffer->datalength = 0;
}
/**
* @}
* @}
*/