stdio.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 73 行

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <stdio.h>
/* #include <sys/types.h> */
#include <fcntl.h>
#include <unistd.h>
#include "local.h"

/*
 * Small standard I/O/seek/close functions.
 * These maintain the `known seek offset' for seek optimisation.
 */

int __sread( void *cookie, char *buf, int n )
{
	register FILE *fp = cookie;
	register int ret;
	
	ret = _read(fp->_file, buf, n);
	/* if the read succeeded, update the current offset */
	if (ret >= 0)
		fp->_offset += ret;
	else
		fp->_flags &= ~__SOFF;	/* paranoia */
	return (ret);
}

int __swrite( void *cookie, const char *buf, int n )
{
	register FILE *fp = cookie;

	if (fp->_flags & __SAPP)
		(void) _lseek(fp->_file, (off_t)0, SEEK_END);
	fp->_flags &= ~__SOFF;	/* in case O_APPEND mode is set */
	return (_write(fp->_file, buf, n));
}

fpos_t __sseek( void *cookie, fpos_t offset, int whence)
{
	register FILE *fp = cookie;
	register off_t ret;
	
	ret = _lseek(fp->_file, (off_t)offset, whence);
	if (ret == -1L)
		fp->_flags &= ~__SOFF;
	else {
		fp->_flags |= __SOFF;
		fp->_offset = ret;
	}
	return (ret);
}

int __sclose( void *cookie )
{

	return (_close(((FILE *)cookie)->_file));
}