usr/src/lib/libc/stdio/stdio.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)stdio.c     5.3 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include "local.h"

/*
 * Small standard I/O/seek/close functions.
 * These maintain the `known seek offset' for seek optimisation.
 */
__sread(cookie, buf, n)
        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);
}

__swrite(cookie, buf, n)
        void *cookie;
        char const *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 FAPPEND mode is set */
        return (write(fp->_file, buf, n));
}

fpos_t
__sseek(cookie, offset, whence)
        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);
}

__sclose(cookie)
        void *cookie;
{

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