?? _open.c
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/***
*_open.c - open a stream, with string mode
*
* Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _openfile() - opens a stream, with string arguments for mode
*
*******************************************************************************/
#ifdef _WIN32
#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 /* _UNICODE */
FILE * __cdecl _openfile (
#endif /* _UNICODE */
const _TSCHAR *filename,
REG3 const _TSCHAR *mode,
int shflag,
FILE *str
)
{
REG2 int modeflag;
int streamflag = _commode;
int commodeset = 0;
int scanset = 0;
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'):
modeflag = _O_RDONLY;
streamflag |= _IOREAD;
break;
case _T('w'):
modeflag = _O_WRONLY | _O_CREAT | _O_TRUNC;
streamflag |= _IOWRT;
break;
case _T('a'):
modeflag = _O_WRONLY | _O_CREAT | _O_APPEND;
streamflag |= _IOWRT;
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('+'):
if (modeflag & _O_RDWR)
whileflag=0;
else {
modeflag |= _O_RDWR;
modeflag &= ~(_O_RDONLY | _O_WRONLY);
streamflag |= _IORW;
streamflag &= ~(_IOREAD | _IOWRT);
}
break;
case _T('b'):
if (modeflag & (_O_TEXT | _O_BINARY))
whileflag=0;
else
modeflag |= _O_BINARY;
break;
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;
default:
whileflag=0;
break;
}
/* Try to open the file. Note that if neither 't' nor 'b' is
specified, _sopen will use the default. */
if ((filedes = _tsopen(filename, modeflag, shflag, CMASK)) < 0)
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);
}
#else /* _WIN32 */
#if defined (_M_MPPC) || defined (_M_M68K)
#include <cruntime.h>
#include <stdio.h>
#include <fcntl.h>
#include <file2.h>
#include <io.h>
#include <dbgint.h>
#include <internal.h>
#define CMASK 0644 /* rw-r--r-- */
/***
*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} and at most one of {cn}. 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:
*
*******************************************************************************/
FILE * __cdecl _openfile (
const char *filename,
REG3 const char *mode,
int shflag,
FILE *str
)
{
REG2 int modeflag;
int streamflag = _commode;
int commodeset = 0;
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 'r':
modeflag = _O_RDONLY;
streamflag |= _IOREAD;
break;
case 'w':
modeflag = _O_WRONLY | _O_CREAT | _O_TRUNC;
streamflag |= _IOWRT;
break;
case 'a':
modeflag = _O_WRONLY | _O_CREAT | _O_APPEND;
streamflag |= _IOWRT;
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 '+':
if (modeflag & _O_RDWR)
whileflag=0;
else {
modeflag |= _O_RDWR;
modeflag &= ~(_O_RDONLY | _O_WRONLY);
streamflag |= _IORW;
streamflag &= ~(_IOREAD | _IOWRT);
}
break;
case 't':
if (modeflag & (_O_TEXT | _O_BINARY))
whileflag=0;
else
modeflag |= _O_TEXT;
break;
case 'b':
if (modeflag & (_O_TEXT | _O_BINARY))
whileflag=0;
else
modeflag |= _O_BINARY;
break;
case 'c':
if (commodeset)
whileflag=0;
else {
commodeset = 1;
streamflag |= _IOCOMMIT;
}
break;
case 'n':
if (commodeset)
whileflag=0;
else {
commodeset = 1;
streamflag &= ~_IOCOMMIT;
}
break;
default:
whileflag=0;
break;
}
/* Try to open the file. Note that if neither 't' nor 'b' is
specified, _sopen will use the default. */
if ((filedes = _sopen(filename, modeflag, shflag, CMASK)) < 0)
return(NULL);
/* Set up the stream data base. */
#ifndef CRTDLL
/* force library pre-termination procedure */
_cflush++;
#endif /* CRTDLL */
/* Init pointers */
stream = str;
stream->_flag = streamflag;
stream->_cnt = 0;
stream->_tmpfname = stream->_base = stream->_ptr = NULL;
stream->_file = filedes;
return(stream);
}
#endif /* defined (_M_MPPC) || defined (_M_M68K) */
#endif /* _WIN32 */
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