mirror of
https://github.com/autc04/Retro68.git
synced 2024-08-28 19:29:05 +00:00
248 lines
7.0 KiB
C
248 lines
7.0 KiB
C
/*
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
FUNCTION
|
|
<<fflush>>---flush buffered file output
|
|
|
|
INDEX
|
|
fflush
|
|
INDEX
|
|
_fflush_r
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <stdio.h>
|
|
int fflush(FILE *<[fp]>);
|
|
|
|
int _fflush_r(struct _reent *<[reent]>, FILE *<[fp]>);
|
|
|
|
DESCRIPTION
|
|
The <<stdio>> output functions can buffer output before delivering it
|
|
to the host system, in order to minimize the overhead of system calls.
|
|
|
|
Use <<fflush>> to deliver any such pending output (for the file
|
|
or stream identified by <[fp]>) to the host system.
|
|
|
|
If <[fp]> is <<NULL>>, <<fflush>> delivers pending output from all
|
|
open files.
|
|
|
|
Additionally, if <[fp]> is a seekable input stream visiting a file
|
|
descriptor, set the position of the file descriptor to match next
|
|
unread byte, useful for obeying POSIX semantics when ending a process
|
|
without consuming all input from the stream.
|
|
|
|
The alternate function <<_fflush_r>> is a reentrant version, where the
|
|
extra argument <[reent]> is a pointer to a reentrancy structure, and
|
|
<[fp]> must not be NULL.
|
|
|
|
RETURNS
|
|
<<fflush>> returns <<0>> unless it encounters a write error; in that
|
|
situation, it returns <<EOF>>.
|
|
|
|
PORTABILITY
|
|
ANSI C requires <<fflush>>. The behavior on input streams is only
|
|
specified by POSIX, and not all implementations follow POSIX rules.
|
|
|
|
No supporting OS subroutines are required.
|
|
*/
|
|
|
|
#include <_ansi.h>
|
|
#include <stdio.h>
|
|
#include <errno.h>
|
|
#include "local.h"
|
|
|
|
/* Flush a single file, or (if fp is NULL) all files. */
|
|
|
|
/* Core function which does not lock file pointer. This gets called
|
|
directly from __srefill. */
|
|
int
|
|
_DEFUN(__sflush_r, (ptr, fp),
|
|
struct _reent *ptr _AND
|
|
register FILE * fp)
|
|
{
|
|
register unsigned char *p;
|
|
register int n, t;
|
|
|
|
t = fp->_flags;
|
|
if ((t & __SWR) == 0)
|
|
{
|
|
/* For a read stream, an fflush causes the next seek to be
|
|
unoptimized (i.e. forces a system-level seek). This conforms
|
|
to the POSIX and SUSv3 standards. */
|
|
fp->_flags |= __SNPT;
|
|
|
|
/* For a seekable stream with buffered read characters, we will attempt
|
|
a seek to the current position now. A subsequent read will then get
|
|
the next byte from the file rather than the buffer. This conforms
|
|
to the POSIX and SUSv3 standards. Note that the standards allow
|
|
this seek to be deferred until necessary, but we choose to do it here
|
|
to make the change simpler, more contained, and less likely
|
|
to miss a code scenario. */
|
|
if ((fp->_r > 0 || fp->_ur > 0) && fp->_seek != NULL)
|
|
{
|
|
int tmp_errno;
|
|
#ifdef __LARGE64_FILES
|
|
_fpos64_t curoff;
|
|
#else
|
|
_fpos_t curoff;
|
|
#endif
|
|
|
|
/* Save last errno and set errno to 0, so we can check if a device
|
|
returns with a valid position -1. We restore the last errno if
|
|
no other error condition has been encountered. */
|
|
tmp_errno = ptr->_errno;
|
|
ptr->_errno = 0;
|
|
/* Get the physical position we are at in the file. */
|
|
if (fp->_flags & __SOFF)
|
|
curoff = fp->_offset;
|
|
else
|
|
{
|
|
/* We don't know current physical offset, so ask for it.
|
|
Only ESPIPE and EINVAL are ignorable. */
|
|
#ifdef __LARGE64_FILES
|
|
if (fp->_flags & __SL64)
|
|
curoff = fp->_seek64 (ptr, fp->_cookie, 0, SEEK_CUR);
|
|
else
|
|
#endif
|
|
curoff = fp->_seek (ptr, fp->_cookie, 0, SEEK_CUR);
|
|
if (curoff == -1L && ptr->_errno != 0)
|
|
{
|
|
int result = EOF;
|
|
if (ptr->_errno == ESPIPE || ptr->_errno == EINVAL)
|
|
{
|
|
result = 0;
|
|
ptr->_errno = tmp_errno;
|
|
}
|
|
else
|
|
fp->_flags |= __SERR;
|
|
return result;
|
|
}
|
|
}
|
|
if (fp->_flags & __SRD)
|
|
{
|
|
/* Current offset is at end of buffer. Compensate for
|
|
characters not yet read. */
|
|
curoff -= fp->_r;
|
|
if (HASUB (fp))
|
|
curoff -= fp->_ur;
|
|
}
|
|
/* Now physically seek to after byte last read. */
|
|
#ifdef __LARGE64_FILES
|
|
if (fp->_flags & __SL64)
|
|
curoff = fp->_seek64 (ptr, fp->_cookie, curoff, SEEK_SET);
|
|
else
|
|
#endif
|
|
curoff = fp->_seek (ptr, fp->_cookie, curoff, SEEK_SET);
|
|
if (curoff != -1 || ptr->_errno == 0
|
|
|| ptr->_errno == ESPIPE || ptr->_errno == EINVAL)
|
|
{
|
|
/* Seek successful or ignorable error condition.
|
|
We can clear read buffer now. */
|
|
fp->_flags &= ~__SNPT;
|
|
fp->_r = 0;
|
|
fp->_p = fp->_bf._base;
|
|
if ((fp->_flags & __SOFF) && (curoff != -1 || ptr->_errno == 0))
|
|
fp->_offset = curoff;
|
|
ptr->_errno = tmp_errno;
|
|
if (HASUB (fp))
|
|
FREEUB (ptr, fp);
|
|
}
|
|
else
|
|
{
|
|
fp->_flags |= __SERR;
|
|
return EOF;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
if ((p = fp->_bf._base) == NULL)
|
|
{
|
|
/* Nothing to flush. */
|
|
return 0;
|
|
}
|
|
n = fp->_p - p; /* write this much */
|
|
|
|
/*
|
|
* Set these immediately to avoid problems with longjmp
|
|
* and to allow exchange buffering (via setvbuf) in user
|
|
* write function.
|
|
*/
|
|
fp->_p = p;
|
|
fp->_w = t & (__SLBF | __SNBF) ? 0 : fp->_bf._size;
|
|
|
|
while (n > 0)
|
|
{
|
|
t = fp->_write (ptr, fp->_cookie, (char *) p, n);
|
|
if (t <= 0)
|
|
{
|
|
fp->_flags |= __SERR;
|
|
return EOF;
|
|
}
|
|
p += t;
|
|
n -= t;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
_DEFUN(_fflush_r, (ptr, fp),
|
|
struct _reent *ptr _AND
|
|
register FILE * fp)
|
|
{
|
|
int ret;
|
|
|
|
#ifdef _REENT_SMALL
|
|
/* For REENT_SMALL platforms, it is possible we are being
|
|
called for the first time on a std stream. This std
|
|
stream can belong to a reentrant struct that is not
|
|
_REENT. If CHECK_INIT gets called below based on _REENT,
|
|
we will end up changing said file pointers to the equivalent
|
|
std stream off of _REENT. This causes unexpected behavior if
|
|
there is any data to flush on the _REENT std stream. There
|
|
are two alternatives to fix this: 1) make a reentrant fflush
|
|
or 2) simply recognize that this file has nothing to flush
|
|
and return immediately before performing a CHECK_INIT. Choice
|
|
2 is implemented here due to its simplicity. */
|
|
if (fp->_bf._base == NULL)
|
|
return 0;
|
|
#endif /* _REENT_SMALL */
|
|
|
|
CHECK_INIT (ptr, fp);
|
|
|
|
if (!fp->_flags)
|
|
return 0;
|
|
|
|
_flockfile (fp);
|
|
ret = __sflush_r (ptr, fp);
|
|
_funlockfile (fp);
|
|
return ret;
|
|
}
|
|
|
|
#ifndef _REENT_ONLY
|
|
|
|
int
|
|
_DEFUN(fflush, (fp),
|
|
register FILE * fp)
|
|
{
|
|
if (fp == NULL)
|
|
return _fwalk_reent (_GLOBAL_REENT, _fflush_r);
|
|
|
|
return _fflush_r (_REENT, fp);
|
|
}
|
|
|
|
#endif /* _REENT_ONLY */
|