134 lines
4.2 KiB
C
134 lines
4.2 KiB
C
/**
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* \file
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* Argument buffer for passing arguments when starting processes
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* \author Adam Dunkels <adam@dunkels.com>
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*/
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/**
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* \addtogroup sys
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* @{
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*/
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/**
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* \defgroup arg Argument buffer
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* @{
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*
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* The argument buffer can be used when passing an argument from an
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* exiting process to a process that has not been created yet. Since
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* the exiting process will have exited when the new process is
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* started, the argument cannot be passed in any of the processes'
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* addres spaces. In such situations, the argument buffer can be used.
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*
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* The argument buffer is statically allocated in memory and is
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* globally accessible to all processes.
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*
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* An argument buffer is allocated with the arg_alloc() function and
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* deallocated with the arg_free() function. The arg_free() function
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* is designed so that it can take any pointer, not just an argument
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* buffer pointer. If the pointer to arg_free() is not an argument
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* buffer, the function does nothing.
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*/
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/*
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* Copyright (c) 2003, Adam Dunkels.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* This file is part of the Contiki desktop OS
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*
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* $Id: arg.c,v 1.1 2006/06/17 22:41:19 adamdunkels Exp $
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*
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*/
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#include "sys/arg.h"
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/**
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* \internal Structure used for holding an argument buffer.
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*/
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struct argbuf {
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char buf[128];
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char used;
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};
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static struct argbuf bufs[1];
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/*-----------------------------------------------------------------------------------*/
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/**
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* \internal Initalizer, called by the dispatcher module.
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*/
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/*-----------------------------------------------------------------------------------*/
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void
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arg_init(void)
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{
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bufs[0].used = 0;
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}
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/*-----------------------------------------------------------------------------------*/
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/**
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* Allocates an argument buffer.
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*
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* \param size The requested size of the buffer, in bytes.
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*
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* \return Pointer to allocated buffer, or NULL if no buffer could be
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* allocated.
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*
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* \note It currently is not possible to allocate argument buffers of
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* any other size than 128 bytes.
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*
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*/
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/*-----------------------------------------------------------------------------------*/
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char *
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arg_alloc(char size)
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{
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if(bufs[0].used == 0) {
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bufs[0].used = 1;
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return bufs[0].buf;
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}
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return 0;
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}
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/*-----------------------------------------------------------------------------------*/
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/**
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* Deallocates an argument buffer.
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*
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* This function deallocates the argument buffer pointed to by the
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* parameter, but only if the buffer actually is an argument buffer
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* and is allocated. It is perfectly safe to call this function with
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* any pointer.
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*
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* \param arg A pointer.
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*/
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/*-----------------------------------------------------------------------------------*/
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void
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arg_free(char *arg)
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{
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if(arg == bufs[0].buf) {
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bufs[0].used = 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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