/***
*_sftbuf.c - temporary buffering initialization and flushing
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* temporary buffering initialization and flushing. if stdout/err is
* unbuffered, buffer it temporarily so that string is sent to kernel as
* a batch of chars, not char-at-a-time. if appropriate, make buffering
* permanent.
*
* [NOTE 1: These routines assume that the temporary buffering is only
* used for output. In particular, note that _stbuf() sets _IOWRT.]
*
* [NOTE 2: It is valid for this module to assign a value directly to
* _flag instead of simply twiddling bits since we are initializing the
* buffer data base.]
*
*Revision History:
* 09-01-83 RN initial version
* 06-26-85 TC added code to _stbuf to allow variable buffer lengths
* ??-??-?? TC fixed case in _flbuf where flag is off, but a temporary
* buffer still needs to be fflushed.
* 05-27-87 JCR protect mode does not know about stdprn.
* 06-26-87 JCR Conditionalized out code in _ftbuf that caused
* redirected stdout to be flushed on every call.
* 07-01-87 JCR Put in code to support re-entrant calling from
* interrupt level (MSC only).
* 08-06-87 JCR Fixed a _ftbuf() problem pertaining to stderr/stdprn
* when _bufout is being used by stdout.
* 08-07-87 JCR (1) When assigning _bufout to an _iob, we now set the
* _IOWRT flag. This fixes a bug involving freopen()
* issued against one of the std handles.
* (2) Removed some annoying commented out code.
* 08-13-87 JCR _ftbuf() does NOT clear _IOWRT now. Fixes a bug where
* _getstream() would reassign stdout because none of the
* flags were set.
* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).
* 11-05-87 JCR Re-written for multi-thread support and simplicity
* 01-11-88 JCR Merged mthread version into normal version
* 01-13-88 SKS Changed bogus "_fileno_lk" to "fileno"
* 06-06-88 JCR Optimized _iob2 references
* 06-10-88 JCR Use near pointer to reference _iob[] entries
* 06-27-88 JCR Added stdprn temporary buffering support (DOS only),
* and made buffer allocation dynamic; also added _IOFLRTN
* (flush stream on per routine basis).
* 08-25-88 GJF Modified to also work for the 386 (small model only).
* 06-20-89 PHG Changed return value to void
* 08-28-89 JCR Removed _NEAR_ for 386
* 02-15-90 GJF _iob[], _iob2[] merge. Also, fixed copyright and
* indents.
* 03-16-90 GJF Made calling type _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>. Also,
* removed some leftover 16-bit DOS support.
* 03-27-90 GJF Added #include <io.h>.
* 05-29-90 SBM Use _flush, not [_]fflush[_lk]
* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
* 10-03-90 GJF New-style function declarator.
* 01-22-91 GJF ANSI naming.
* 03-27-92 DJM POSIX support.
* 08-26-92 GJF Include unistd.h for POSIX build.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 05-11-93 GJF Replaced BUFSIZ with _INTERNAL_BUFSIZ.
* 04-05-94 GJF #ifdef-ed out _cflush reference for msvcrt*.dll, it
* is unnecessary. Also, replaced MTHREAD with _MT.
* 01-10-95 CFW Debug CRT allocs.
* 02-06-94 CFW assert -> _ASSERTE.
* 02-17-95 GJF Merged in Mac version.
* 02-07-97 GJF Changed _stbuf() to use _charbuf when malloc fails.
* Also, detab-ed.
* 05-17-99 PML Remove all Macintosh support.
*
*******************************************************************************/
#include <cruntime.h>
#ifdef _POSIX_
#include <unistd.h>
#endif
#include <stdio.h>
#include <file2.h>
#include <io.h>
#include <internal.h>
#include <malloc.h>
#ifdef _MT
#include <mtdll.h>
#endif
#include <dbgint.h>
/* Buffer pointers for stdout and stderr */
void *_stdbuf[2] = { NULL, NULL};
/***
*int _stbuf(stream) - set temp buffer on stdout, stdprn, stderr
*
*Purpose:
* if stdout/stderr is still unbuffered, buffer it.
* this function works intimately with _ftbuf, and accompanies it in
* bracketing normally unbuffered output. these functions intended for
* library use only.
*
* Multi-thread: It is assumed that the caller has already aquired the
* stream lock.
*
*Entry:
* FILE *stream - stream to temp buffer
*
*Exit:
* returns 1 if buffer initialized, 0 if not
* sets fields in stdout or stderr to indicate buffering
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _stbuf (
FILE *str
)
{
REG1 FILE *stream;
int index;
_ASSERTE(str != NULL);
/* Init near stream pointer */
stream = str;
/* do nothing if not a tty device */
#ifdef _POSIX_
if (!isatty(fileno(stream)))
#else
if (!_isatty(_fileno(stream)))
#endif
return(0);
/* Make sure stream is stdout/stderr and init _stdbuf index */
if (stream == stdout)
index = 0;
else if (stream == stderr)
index = 1;
else
return(0);
#ifndef CRTDLL
/* force library pre-termination procedure */
_cflush++;
#endif /* CRTDLL */
/* Make sure the stream is not already buffered. */
if (anybuf(stream))
return(0);
/* Allocate a buffer for this stream if we haven't done so yet. */
if ( (_stdbuf[index] == NULL) &&
((_stdbuf[index]=_malloc_crt(_INTERNAL_BUFSIZ)) == NULL) ) {
/* Cannot allocate buffer. Use _charbuf this time */
stream->_ptr = stream->_base = (void *)&(stream->_charbuf);
stream->_cnt = stream->_bufsiz = 2;
}
else {
/* Set up the buffer */
stream->_ptr = stream->_base = _stdbuf[index];
stream->_cnt = stream->_bufsiz = _INTERNAL_BUFSIZ;
}
stream->_flag |= (_IOWRT | _IOYOURBUF | _IOFLRTN);
return(1);
}
/***
*void _ftbuf(flag, stream) - take temp buffering off a stream
*
*Purpose:
* If stdout/stderr is being buffered and it is a device, _flush and
* dismantle the buffer. if it's not a device, leave the buffering on.
* This function works intimately with _stbuf, and accompanies it in
* bracketing normally unbuffered output. these functions intended for
* library use only
*
* Multi-thread: It is assumed that the caller has already aquired the
* stream lock.
*
*Entry:
* int flag - a flag to tell whether to dismantle temp buffering on a
* stream
* FILE *stream - the stream
*
*Exit:
* no return value
* sets fields in stdout/stderr
*
*Exceptions:
*
*******************************************************************************/
void __cdecl _ftbuf (
int flag,
FILE *str
)
{
REG1 FILE *stream;
_ASSERTE(flag == 0 || flag == 1);
/* Init near stream pointers */
stream = str;
if (flag) {
if (stream->_flag & _IOFLRTN) {
/* Flush the stream and tear down temp buffering. */
_flush(stream);
stream->_flag &= ~(_IOYOURBUF | _IOFLRTN);
stream->_bufsiz = 0;
stream->_base = stream->_ptr = NULL;
}
/* Note: If we expand the functionality of the _IOFLRTN bit to
include other streams, we may want to clear that bit here under
an 'else' clause (i.e., clear bit in the case that we leave the
buffer permanently assigned. Given our current use of the bit,
the extra code is not needed. */
} /* end flag = 1 */
#ifndef _MT
/* NOTE: Currently, writing to the same string at interrupt level does not
work in multi-thread programs. */
/* The following code is needed if an interrupt occurs between calls
to _stbuf/_ftbuf and the interrupt handler also calls _stbuf/_ftbuf. */
else
if (stream->_flag & _IOFLRTN)
_flush(stream);
#endif /* _MT */
}