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/***
*_open.c - open a stream, with string mode** Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.**Purpose:* defines _openfile() - opens a stream, with string arguments for mode**Revision History:* 09-02-83 RN initial version* 03-02-87 JCR made _openfile recognize "wb+" as equal to "w+b", etc.* got rid of intermediate _openfile flags (internal) and* now go straight from mode string to open system call* and system->_flags.* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).* 02-21-88 SKS Removed #ifdef IBMC20* 06-06-88 JCR Optimized _iob2 references* 06-10-88 JCR Use near pointer to reference _iob[] entries* 08-19-88 GJF Initial adaption for the 386.* 11-14-88 GJF Added shflag (file sharing flag) parameter, also some* cleanup (now specific to the 386).* 08-17-89 GJF Clean up, now specific to OS/2 2.0 (i.e., 386 flat* model). Also fixed copyright and indents.* 02-15-90 GJF _iob[], _iob2[] merge. Also, fixed copyright.* 03-16-90 GJF Made calling type _CALLTYPE1, added #include* <cruntime.h> and removed #include <register.h>.* 03-27-90 GJF Added const qualifier to types of filename and mode.* Added #include <io.h>.* 07-11-90 SBM Added support for 'c' and 'n' flags* 07-23-90 SBM Replaced <assertm.h> by <assert.h>* 10-03-90 GJF New-style function declarator.* 01-18-91 GJF ANSI naming.* 03-11-92 GJF Replaced __tmpnum field with _tmpfname field for* Win32.* 03-25-92 DJM POSIX support.* 08-26-92 GJF Fixed POSIX support.* 04-06-93 SKS Replace _CRTAPI* with __cdecl* 05-24-93 PML Added support for 'D', 'R', 'S' and 'T' flags* 11-01-93 CFW Enable Unicode variant, rip out CRUISER.* 04-05-94 GJF #ifdef-ed out _cflush reference for msvcrt*.dll, it* is unnecessary.* 02-06-94 CFW assert -> _ASSERTE.* 02-17-95 GJF Appended Mac version of source file (somewhat cleaned* up), with appropriate #ifdef-s.* 05-17-99 PML Remove all Macintosh support.********************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <fcntl.h>
#include <file2.h>
#include <io.h>
#include <dbgint.h>
#include <internal.h>
#include <tchar.h>
#define CMASK 0644 /* rw-r--r-- */
#define P_CMASK 0666 /* different for Posix */
/***
*FILE *_openfile(filename, mode, shflag, stream) - open a file with string* mode and file sharing flag.**Purpose:* parse the string, looking for exactly one of {rwa}, at most one '+',* at most one of {tb}, at most one of {cn}, at most one of {SR}, at most* one 'T', and at most one 'D'. pass the result on as an int containing* flags of what was found. open a file with proper mode if permissions* allow. buffer not allocated until first i/o call is issued. intended* for use inside library only**Entry:* char *filename - file to open* char *mode - mode to use (see above)* int shflag - file sharing flag* FILE *stream - stream to use for file**Exit:* set stream's fields, and causes system file management by system calls* returns stream or NULL if fails**Exceptions:********************************************************************************/
#ifdef _UNICODE
FILE * __cdecl _wopenfile (#else
FILE * __cdecl _openfile (#endif
const _TSCHAR *filename, REG3 const _TSCHAR *mode,#ifndef _POSIX_
int shflag,#endif
FILE *str ){ REG2 int modeflag;#ifdef _POSIX_
int streamflag = 0;#else
int streamflag = _commode; int commodeset = 0; int scanset = 0;#endif
int whileflag; int filedes; REG1 FILE *stream;
_ASSERTE(filename != NULL); _ASSERTE(mode != NULL); _ASSERTE(str != NULL);
/* Parse the user's specification string as set flags in
(1) modeflag - system call flags word (2) streamflag - stream handle flags word. */
/* First mode character must be 'r', 'w', or 'a'. */
switch (*mode) { case _T('r'):#ifdef _POSIX_
modeflag = O_RDONLY;#else
modeflag = _O_RDONLY;#endif
streamflag |= _IOREAD; break; case _T('w'):#ifdef _POSIX_
modeflag = O_WRONLY | O_CREAT | O_TRUNC;#else
modeflag = _O_WRONLY | _O_CREAT | _O_TRUNC;#endif
streamflag |= _IOWRT; break; case _T('a'):#ifdef _POSIX_
modeflag = O_WRONLY | O_CREAT | O_APPEND; streamflag |= _IOWRT | _IOAPPEND;#else
modeflag = _O_WRONLY | _O_CREAT | _O_APPEND; streamflag |= _IOWRT;#endif
break; default: return(NULL); break; }
/* There can be up to three more optional mode characters:
(1) A single '+' character, (2) One of 't' and 'b' and (3) One of 'c' and 'n'. */
whileflag=1;
while(*++mode && whileflag) switch(*mode) {
case _T('+'):#ifdef _POSIX_
if (modeflag & O_RDWR) whileflag=0; else { modeflag |= O_RDWR; modeflag &= ~(O_RDONLY | O_WRONLY);#else
if (modeflag & _O_RDWR) whileflag=0; else { modeflag |= _O_RDWR; modeflag &= ~(_O_RDONLY | _O_WRONLY);#endif
streamflag |= _IORW; streamflag &= ~(_IOREAD | _IOWRT); } break;
case _T('b'):#ifndef _POSIX_
if (modeflag & (_O_TEXT | _O_BINARY)) whileflag=0; else modeflag |= _O_BINARY;#endif
break;
#ifndef _POSIX_
case _T('t'): if (modeflag & (_O_TEXT | _O_BINARY)) whileflag=0; else modeflag |= _O_TEXT; break;
case _T('c'): if (commodeset) whileflag=0; else { commodeset = 1; streamflag |= _IOCOMMIT; } break;
case _T('n'): if (commodeset) whileflag=0; else { commodeset = 1; streamflag &= ~_IOCOMMIT; } break;
case _T('S'): if (scanset) whileflag=0; else { scanset = 1; modeflag |= _O_SEQUENTIAL; } break;
case _T('R'): if (scanset) whileflag=0; else { scanset = 1; modeflag |= _O_RANDOM; } break;
case _T('T'): if (modeflag & _O_SHORT_LIVED) whileflag=0; else modeflag |= _O_SHORT_LIVED; break;
case _T('D'): if (modeflag & _O_TEMPORARY) whileflag=0; else modeflag |= _O_TEMPORARY; break;#endif
default: whileflag=0; break; }
/* Try to open the file. Note that if neither 't' nor 'b' is
specified, _sopen will use the default. */
#ifdef _POSIX_
if ((filedes = _topen(filename, modeflag, P_CMASK)) < 0)#else
if ((filedes = _tsopen(filename, modeflag, shflag, CMASK)) < 0)#endif
return(NULL);
/* Set up the stream data base. */#ifndef CRTDLL
_cflush++; /* force library pre-termination procedure */#endif /* CRTDLL */
/* Init pointers */ stream = str;
stream->_flag = streamflag; stream->_cnt = 0; stream->_tmpfname = stream->_base = stream->_ptr = NULL;
stream->_file = filedes;
return(stream);}
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