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206 lines
6.3 KiB
206 lines
6.3 KiB
/***
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*fdopen.c - open a file descriptor as stream
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*
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* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* defines _fdopen() - opens a file descriptor as a stream, thus allowing
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* buffering, etc.
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*
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*Revision History:
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* 09-02-83 RN initial version
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* 03-02-87 JCR added support for 'b' and 't' embedded in mode strings
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* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).
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* 11-03-87 JCR Multi-thread support
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* 12-11-87 JCR Added "_LOAD_DS" to declaration
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* 05-31-88 PHG Merged DLL and normal versions
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* 06-06-88 JCR Optimized _iob2 references
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* 11-20-89 GJF Fixed copyright, indents. Added const to type of mode.
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* 02-15-90 GJF _iob[], _iob2[] merge.
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* 03-16-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
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* <cruntime.h> and removed #include <register.h>.
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* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
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* 08-24-90 SBM Added support for 'c' and 'n' flags
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* 10-02-90 GJF New-style function declarator.
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* 01-21-91 GJF ANSI naming.
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* 02-14-92 GJF Replaced _nfile with _nhandle for Win32.
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* 05-01-92 DJM Replaced _nfile with OPEN_MAX for POSIX.
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* 08-03-92 GJF Function name must be "fdopen" for POSIX.
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 12-07-93 CFW Wide char enable.
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* 04-05-94 GJF #ifdef-ed out _cflush reference for msvcrt*.dll, it
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* is unnecessary.
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* 09-06-94 CFW Replace MTHREAD with _MT.
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* 01-04-95 GJF _WIN32_ -> _WIN32.
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* 02-06-94 CFW assert -> _ASSERTE.
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* 02-17-95 GJF Merged in Mac version.
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* 03-07-95 GJF _[un]lock_str macros now take FILE * arg.
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* 10-20-95 GJF Added checks to passed supplied handle is open (for
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* Win32 and Mac builds) (Olympus0 10153).
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* 09-26-97 BWT Fix POSIX
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* 02-26-98 GJF Exception-safe locking.
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* 05-17-99 PML Remove all Macintosh support.
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* 10-06-99 PML Set errno EMFILE when out of streams.
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* 04-26-02 PML Fix AV on bogus mode param (VS7#526205)
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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <msdos.h>
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#include <stdio.h>
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#include <file2.h>
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#include <dbgint.h>
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#include <internal.h>
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#include <mtdll.h>
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#ifdef _POSIX_
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#include <limits.h>
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#endif
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#include <tchar.h>
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#include <errno.h>
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/***
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*FILE *_fdopen(filedes, mode) - open a file descriptor as a stream
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*
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*Purpose:
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* associates a stream with a file handle, thus allowing buffering, etc.
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* The mode must be specified and must be compatible with the mode
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* the file was opened with in the low level open.
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*
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*Entry:
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* int filedes - handle referring to open file
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* _TSCHAR *mode - file mode to use ("r", "w", "a", etc.)
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*
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*Exit:
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* returns stream pointer and sets FILE struct fields if successful
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* returns NULL if fails
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*
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*Exceptions:
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*
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*******************************************************************************/
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FILE * __cdecl _tfdopen (
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int filedes,
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REG2 const _TSCHAR *mode
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)
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{
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REG1 FILE *stream;
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int whileflag, tbflag, cnflag;
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int fileflag;
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_ASSERTE(mode != NULL);
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#if !defined(_POSIX_)
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_ASSERTE((unsigned)filedes < (unsigned)_nhandle);
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_ASSERTE(_osfile(filedes) & FOPEN);
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if ( ((unsigned)filedes >= (unsigned)_nhandle) ||
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!(_osfile(filedes) & FOPEN) )
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return(NULL);
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#else
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_ASSERTE((unsigned)filedes < OPEN_MAX);
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if ((unsigned)filedes >= OPEN_MAX)
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return(NULL);
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#endif /* !_POSIX_ */
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/* First character must be 'r', 'w', or 'a'. */
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switch (*mode) {
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case _T('r'):
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fileflag = _IOREAD;
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break;
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case _T('w'):
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case _T('a'):
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fileflag = _IOWRT;
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break;
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default:
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return(NULL); /* error */
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}
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/* There can be up to three more optional characters:
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(1) A single '+' character,
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(2) One of 'b' and 't' and
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(3) One of 'c' and 'n'.
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Note that currently, the 't' and 'b' flags are syntax checked
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but ignored. 'c' and 'n', however, are correctly supported.
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*/
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whileflag=1;
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tbflag=cnflag=0;
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fileflag |= _commode;
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while(*++mode && whileflag)
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switch(*mode) {
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case _T('+'):
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if (fileflag & _IORW)
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whileflag=0;
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else {
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fileflag |= _IORW;
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fileflag &= ~(_IOREAD | _IOWRT);
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}
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break;
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case _T('b'):
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case _T('t'):
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if (tbflag)
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whileflag=0;
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else
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tbflag=1;
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break;
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case _T('c'):
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if (cnflag)
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whileflag = 0;
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else {
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cnflag = 1;
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fileflag |= _IOCOMMIT;
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}
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break;
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case _T('n'):
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if (cnflag)
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whileflag = 0;
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else {
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cnflag = 1;
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fileflag &= ~_IOCOMMIT;
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}
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break;
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default:
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whileflag=0;
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break;
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}
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/* Find a free stream; stream is returned 'locked'. */
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if ((stream = _getstream()) == NULL) {
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errno = EMFILE;
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return(NULL);
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}
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#ifdef _MT
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__try {
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#endif
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#ifndef CRTDLL
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_cflush++; /* force library pre-termination procedure */
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#endif /* CRTDLL */
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stream->_flag = fileflag;
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stream->_file = filedes;
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#ifdef _MT
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}
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__finally {
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_unlock_str(stream);
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}
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#endif
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return(stream);
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}
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