You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
159 lines
5.1 KiB
159 lines
5.1 KiB
/***
|
|
*stream.c - find a stream not in use
|
|
*
|
|
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
|
|
*
|
|
*Purpose:
|
|
* defines _getstream() - find a stream not in use
|
|
*
|
|
*Revision History:
|
|
* 09-02-83 RN initial version
|
|
* 11-01-87 JCR Multi-thread support
|
|
* 05-24-88 PHG Merged DLL and normal versions
|
|
* 06-10-88 JCR Use near pointer to reference _iob[] entries
|
|
* 08-17-89 GJF Removed _NEAR_, fixed copyright and indenting.
|
|
* 02-16-90 GJF Fixed copyright
|
|
* 03-19-90 GJF Made calling type _CALLTYPE1, added #include
|
|
* <cruntime.h> and removed #include <register.h>.
|
|
* 10-03-90 GJF New-style function declarator.
|
|
* 12-31-91 GJF Improved multi-thread lock usage [_WIN32_].
|
|
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
|
|
* 09-06-94 CFW Replace MTHREAD with _MT.
|
|
* 03-07-95 GJF Changes to manage streams via __piob[], rather than
|
|
* _iob[].
|
|
* 05-12-95 CFW Bug fix: set _tmpfname field to NULL.
|
|
* 03-02-98 GJF Exception-safe locking.
|
|
* 05-13-99 PML Remove Win32s
|
|
* 05-17-99 PML Remove all Macintosh support.
|
|
* 10-14-99 PML Replace InitializeCriticalSection with wrapper function
|
|
* __crtInitCritSecAndSpinCount
|
|
* 02-20-01 PML vs7#172586 Avoid _RT_LOCK by preallocating all locks
|
|
* that will be required, and returning failure back on
|
|
* inability to allocate a lock.
|
|
*
|
|
*******************************************************************************/
|
|
|
|
#include <cruntime.h>
|
|
#include <windows.h>
|
|
#include <malloc.h>
|
|
#include <stdio.h>
|
|
#include <file2.h>
|
|
#include <internal.h>
|
|
#include <mtdll.h>
|
|
#include <dbgint.h>
|
|
|
|
/***
|
|
*FILE *_getstream() - find a stream not in use
|
|
*
|
|
*Purpose:
|
|
* Find a stream not in use and make it available to caller. Intended
|
|
* for use inside library only
|
|
*
|
|
*Entry:
|
|
* None. Scans __piob[]
|
|
*
|
|
*Exit:
|
|
* Returns a pointer to a free stream, or NULL if all are in use. A
|
|
* stream becomes allocated if the caller decided to use it by setting
|
|
* any r, w, r/w mode.
|
|
*
|
|
* [Multi-thread note: If a free stream is found, it is returned in a
|
|
* LOCKED state. It is the caller's responsibility to unlock the stream.]
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
FILE * __cdecl _getstream (
|
|
void
|
|
)
|
|
{
|
|
REG2 FILE *retval = NULL;
|
|
REG1 int i;
|
|
|
|
#ifdef _MT
|
|
/* Get the iob[] scan lock */
|
|
_mlock(_IOB_SCAN_LOCK);
|
|
__try {
|
|
#endif
|
|
|
|
/*
|
|
* Loop through the __piob table looking for a free stream, or the
|
|
* first NULL entry.
|
|
*/
|
|
for ( i = 0 ; i < _nstream ; i++ ) {
|
|
|
|
if ( __piob[i] != NULL ) {
|
|
/*
|
|
* if the stream is not inuse, return it.
|
|
*/
|
|
if ( !inuse( (FILE *)__piob[i] ) ) {
|
|
#ifdef _MT
|
|
/*
|
|
* Allocate the FILE lock, in case it hasn't already been
|
|
* allocated (only necessary for the first _IOB_ENTRIES
|
|
* locks, not including stdin/stdout/stderr). Return
|
|
* failure if lock can't be allocated.
|
|
*/
|
|
if ( i > 2 && i < _IOB_ENTRIES )
|
|
if ( !_mtinitlocknum( _STREAM_LOCKS + i ) )
|
|
break;
|
|
|
|
_lock_str2(i, __piob[i]);
|
|
|
|
if ( inuse( (FILE *)__piob[i] ) ) {
|
|
_unlock_str2(i, __piob[i]);
|
|
continue;
|
|
}
|
|
#endif
|
|
retval = (FILE *)__piob[i];
|
|
break;
|
|
}
|
|
}
|
|
else {
|
|
/*
|
|
* allocate a new _FILEX, set _piob[i] to it and return a
|
|
* pointer to it.
|
|
*/
|
|
if ( (__piob[i] = _malloc_crt( sizeof(_FILEX) )) != NULL ) {
|
|
|
|
#if defined(_MT)
|
|
if ( !__crtInitCritSecAndSpinCount(
|
|
&(((_FILEX *)__piob[i])->lock), _CRT_SPINCOUNT ))
|
|
{
|
|
/*
|
|
* Failed to initialize the critical section because
|
|
* of lack of memory, clean up and return failure.
|
|
*/
|
|
_free_crt( __piob[i] );
|
|
__piob[i] = NULL;
|
|
break;
|
|
}
|
|
|
|
EnterCriticalSection( &(((_FILEX *)__piob[i])->lock) );
|
|
#endif
|
|
retval = (FILE *)__piob[i];
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Initialize the return stream.
|
|
*/
|
|
if ( retval != NULL ) {
|
|
retval->_flag = retval->_cnt = 0;
|
|
retval->_tmpfname = retval->_ptr = retval->_base = NULL;
|
|
retval->_file = -1;
|
|
}
|
|
|
|
#ifdef _MT
|
|
}
|
|
__finally {
|
|
_munlock(_IOB_SCAN_LOCK);
|
|
}
|
|
#endif
|
|
|
|
return(retval);
|
|
}
|