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gnuindent -npro -kr -i8 -ts8 -sob -ss -ncs -cp1 -il0 -hnl -l150 git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1836 ebee16cc-31ac-478f-84a7-5cbb03baadba
235 lines
6.4 KiB
C
235 lines
6.4 KiB
C
/**
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******************************************************************************
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*
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* @addtogroup OpenPilotModules OpenPilot Modules
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* @{
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* @addtogroup Flight_Libraries Miscellaneous library functions
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* @brief Miscellaneous library functions shared between PIOS / OpenPilot / AHRS
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* @{
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*
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* @file buffer.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* @brief Simplies buffering data
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* @see The GNU Public License (GPL) Version 3
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*
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*****************************************************************************/
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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//*****************************************************************************
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//
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// File Name : 'buffer.c'
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// Title : Multipurpose byte buffer structure and methods
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// Author : Pascal Stang - Copyright (C) 2001-2002
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// Created : 9/23/2001
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// Revised : 9/23/2001
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// Version : 1.0
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// Target MCU : any
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// Editor Tabs : 4
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//
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// This code is distributed under the GNU Public License
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// which can be found at http://www.gnu.org/licenses/gpl.txt
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//
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//*****************************************************************************
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#include "buffer.h"
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/**
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* @brief Initialize a cBuffer structure
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* @param[in] buffer Points to the buffer structure
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* @param[in] start Allocated memory to store data
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* @param[in] size Maximum size of buffer
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* @return None
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*/
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void bufferInit(cBuffer * buffer, uint8_t * start, uint32_t size)
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{
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// set start pointer of the buffer
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buffer->dataptr = start;
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buffer->size = size;
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// initialize index and length
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buffer->dataindex = 0;
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buffer->datalength = 0;
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}
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/**
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* @brief Return remaining space in buffer
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* @param[in] buffer Pointer to buffer structure
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* @return Amount of space remaining on buffer
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*/
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uint32_t bufferRemainingSpace(cBuffer * buffer)
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{
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return buffer->size - buffer->datalength;
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}
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/**
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* @brief Return amount of data
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* @param[in] buffer Pointer to buffer structure
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* @return Amount of data queued in buffer
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*/
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uint32_t bufferBufferedData(cBuffer * buffer)
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{
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return buffer->datalength;
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}
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/**
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* @brief Pop one element from buffer
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* @param[in] buffer Pointer to the buffer structure
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* @return None
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*/
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uint8_t bufferGetFromFront(cBuffer * buffer)
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{
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unsigned char data = 0;
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// check to see if there's data in the buffer
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if (buffer->datalength) {
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// get the first character from buffer
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data = buffer->dataptr[buffer->dataindex];
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// move index down and decrement length
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buffer->dataindex++;
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if (buffer->dataindex >= buffer->size) {
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buffer->dataindex %= buffer->size;
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}
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buffer->datalength--;
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}
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// return
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return data;
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}
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/**
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* @brief Copy number of elements into another buffer
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* @param[in] buffer Pointer to the buffer structure
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* @param[in] dest Point to destimation, must be allocated enough space for size
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* @param[in] size Number of elements to get
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* @return
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* @arg -1 for success
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* @arg 0 error
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*/
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uint8_t bufferGetChunkFromFront(cBuffer * buffer, uint8_t * dest, uint32_t size)
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{
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if (size > buffer->datalength)
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return -1;
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for (uint32_t i = 0; i < size; i++) {
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dest[i] = bufferGetFromFront(buffer);
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}
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return 0;
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}
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/**
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* @brief Shift index to trash data from front of buffer
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* @param[in] buffer Pointer to buffer structure
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* @param[in] numbytes Number of bytes to drop
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* @return None
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*/
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void bufferDumpFromFront(cBuffer * buffer, uint32_t numbytes)
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{
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// dump numbytes from the front of the buffer
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// are we dumping less than the entire buffer?
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if (numbytes < buffer->datalength) {
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// move index down by numbytes and decrement length by numbytes
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buffer->dataindex += numbytes;
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if (buffer->dataindex >= buffer->size) {
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buffer->dataindex %= buffer->size;
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}
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buffer->datalength -= numbytes;
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} else {
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// flush the whole buffer
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buffer->datalength = 0;
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}
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}
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/**
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* @brief Get element indexed from the front of buffer
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* @param[in] buffer Point to the buffer structure
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* @param[in] index Index into the buffer relative to front
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* @return None
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*/
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uint8_t bufferGetAtIndex(cBuffer * buffer, uint32_t index)
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{
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// return character at index in buffer
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return buffer->dataptr[(buffer->dataindex + index) % (buffer->size)];
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}
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/**
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* @brief Queue a character to end of buffer
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* @param[in] buffer Point to the buffer structure
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* @param[in] data Byte to add
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* @return
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* @arg -1 for success
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* @arg 0 error
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*/
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uint8_t bufferAddToEnd(cBuffer * buffer, uint8_t data)
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{
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// make sure the buffer has room
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if (buffer->datalength < buffer->size) {
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// save data byte at end of buffer
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buffer->dataptr[(buffer->dataindex + buffer->datalength) % buffer->size] = data;
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// increment the length
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buffer->datalength++;
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// return success
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return -1;
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} else
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return 0;
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}
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/**
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* @brief Queue a block of character to end of buffer
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* @param[in] buffer Point to the buffer structure
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* @param[in] data Pointer to data to add
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* @param[in] size Number of bytes to add
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* @return
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* @arg -1 for success
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* @arg 0 error
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*/
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uint8_t bufferAddChunkToEnd(cBuffer * buffer, const uint8_t * data, uint32_t size)
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{
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// TODO: replace with memcpy and logic, for now keeping it simple
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for (uint32_t i = 0; i < size; i++) {
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if (bufferAddToEnd(buffer, data[i]) == 0)
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return 0;
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}
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return -1;
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}
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/**
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* @brief Check to see if the buffer has room
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* @param[in] buffer Point to the buffer structure
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* @return
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* @arg True there is room available in buffer
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* @arg False buffer is full
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*/
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unsigned char bufferIsNotFull(cBuffer * buffer)
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{
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return (buffer->datalength < buffer->size);
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}
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/**
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* @brief Trash all data in buffer
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* @param[in] buffer Point to the buffer structure
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*/
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void bufferFlush(cBuffer * buffer)
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{
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// flush contents of the buffer
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buffer->datalength = 0;
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}
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/**
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* @}
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* @}
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*/
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