/** * \file * Argument buffer for passing arguments when starting processes * \author Adam Dunkels <adam@dunkels.com> */ /** * \addtogroup sys * @{ */ /** * \defgroup arg Argument buffer * @{ * * The argument buffer can be used when passing an argument from an * exiting process to a process that has not been created yet. Since * the exiting process will have exited when the new process is * started, the argument cannot be passed in any of the processes' * addres spaces. In such situations, the argument buffer can be used. * * The argument buffer is statically allocated in memory and is * globally accessible to all processes. * * An argument buffer is allocated with the arg_alloc() function and * deallocated with the arg_free() function. The arg_free() function * is designed so that it can take any pointer, not just an argument * buffer pointer. If the pointer to arg_free() is not an argument * buffer, the function does nothing. */ /* * Copyright (c) 2003, Adam Dunkels. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * 3. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * This file is part of the Contiki desktop OS * * $Id: arg.c,v 1.2 2006/08/14 23:39:23 oliverschmidt Exp $ * */ #include "contiki.h" #include "sys/arg.h" /** * \internal Structure used for holding an argument buffer. */ struct argbuf { char buf[128]; char used; }; static struct argbuf bufs[1]; /*-----------------------------------------------------------------------------------*/ /** * \internal Initalizer, called by the dispatcher module. */ /*-----------------------------------------------------------------------------------*/ void arg_init(void) { bufs[0].used = 0; } /*-----------------------------------------------------------------------------------*/ /** * Allocates an argument buffer. * * \param size The requested size of the buffer, in bytes. * * \return Pointer to allocated buffer, or NULL if no buffer could be * allocated. * * \note It currently is not possible to allocate argument buffers of * any other size than 128 bytes. * */ /*-----------------------------------------------------------------------------------*/ char * arg_alloc(char size) { if(bufs[0].used == 0) { bufs[0].used = 1; return bufs[0].buf; } return 0; } /*-----------------------------------------------------------------------------------*/ /** * Deallocates an argument buffer. * * This function deallocates the argument buffer pointed to by the * parameter, but only if the buffer actually is an argument buffer * and is allocated. It is perfectly safe to call this function with * any pointer. * * \param arg A pointer. */ /*-----------------------------------------------------------------------------------*/ void arg_free(char *arg) { if(arg == bufs[0].buf) { bufs[0].used = 0; } } /*-----------------------------------------------------------------------------------*/ /** @} */ /** @} */