rio.c

来自「一个收集所有最基本功能的函数库；所有的函数都是尽量短小和简单 使用 doxyge」· C语言 代码 · 共 90 行

/***************************************************************************
 *            rio.c
 *
 *  Mon May 21 18:08:10 2007
 *  Copyright  2007  kf701
 *  Email <kf701.ye AT gmail.com>
 ****************************************************************************/

/*
 *  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 2 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.
 */
 

#include <errno.h>

#include "kf701.h"

/**
 * @brief robust read wrapper for unix
 * 
 * Note: but in Linux, read have the same function
 *
 * @return same as read syscall
 */
int32_t rio_read(int fd , void * buf , uint32_t size)
{
	int nleft = size;
	int nread;
	char * bufp = buf;
	
	while( nleft > 0 )
	{
		if( (nread = read( fd , bufp , nleft )) < 0 )
		{
			if( errno == EINTR )
				nread = 0;
			else if( errno == EAGAIN )
				break;
			else
				return -1;
		}
		else if ( nread == 0 )
			break;
		
		nleft -= nread;
		bufp += nread;
	}
	return (size - nleft);
}

/**
 * @brief robust write wrapper for unix
 *
 * Note: in Linux, write have the same function
 *
 * @return same as write syscall
 */
int32_t rio_write(int fd , void * buf , uint32_t size)
{
	uint32_t nleft = size;
	int32_t nwrite;
	char * bufp = buf;

	while( nleft > 0 )
	{
		if((nwrite = write( fd, bufp , nleft )) <= 0 )
		{
			if( errno == EINTR )
				nwrite = 0;
			else
				return -1;
		}
		nleft -= nwrite;
		bufp += nwrite;
	}
	return size;
}