/***
*fdopen.c - open a file descriptor as stream
*
* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _fdopen() - opens a file descriptor as a stream, thus allowing
* buffering, etc.
*
*Revision History:
* 09-02-83 RN initial version
* 03-02-87 JCR added support for 'b' and 't' embedded in mode strings
* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).
* 11-03-87 JCR Multi-thread support
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-31-88 PHG Merged DLL and normal versions
* 06-06-88 JCR Optimized _iob2 references
* 11-20-89 GJF Fixed copyright, indents. Added const to type of mode.
* 02-15-90 GJF _iob[], _iob2[] merge.
* 03-16-90 GJF Replaced _LOAD_DS with _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>.
* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
* 08-24-90 SBM Added support for 'c' and 'n' flags
* 10-02-90 GJF New-style function declarator.
* 01-21-91 GJF ANSI naming.
* 02-14-92 GJF Replaced _nfile with _nhandle for Win32.
* 05-01-92 DJM Replaced _nfile with OPEN_MAX for POSIX.
* 08-03-92 GJF Function name must be "fdopen" for POSIX.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <file2.h>
#include <assert.h>
#include <internal.h>
#include <os2dll.h>
#ifdef _POSIX_
#include <limits.h>
#endif
/***
*FILE *_fdopen(filedes, mode) - open a file descriptor as a stream
*
*Purpose:
* associates a stream with a file handle, thus allowing buffering, etc.
* The mode must be specified and must be compatible with the mode
* the file was opened with in the low level open.
*
*Entry:
* int filedes - handle referring to open file
* char *mode - file mode to use ("r", "w", "a", etc.)
*
*Exit:
* returns stream pointer and sets FILE struct fields if successful
* returns NULL if fails
*
*Exceptions:
*
*******************************************************************************/
#ifdef _POSIX_
FILE * _CALLTYPE1 fdopen (
#else
FILE * _CALLTYPE1 _fdopen (
#endif
int filedes,
REG2 const char *mode
)
{
REG1 FILE *stream;
int whileflag, tbflag, cnflag;
#ifdef MTHREAD
int index;
#endif
assert(mode != NULL);
#ifdef _WIN32_
assert(filedes < _nhandle);
if ( (unsigned)filedes >= (unsigned)_nhandle )
return(NULL);
#else
#ifdef _POSIX_
assert(filedes < OPEN_MAX);
if (filedes < 0 || filedes >= OPEN_MAX)
return(NULL);
#else
assert(filedes < _nfile);
if (filedes < 0 || filedes >= _nfile)
return(NULL);
#endif /* _POSIX_ */
#endif /* _WIN32_ */
/* Find a free stream; stream is returned 'locked'. */
if ((stream = _getstream()) == NULL)
return(NULL);
#ifdef MTHREAD
index = _iob_index(stream);
#endif
/* First character must be 'r', 'w', or 'a'. */
switch (*mode) {
case 'r':
stream->_flag = _IOREAD;
break;
case 'w':
case 'a':
stream->_flag = _IOWRT;
break;
default:
stream = NULL; /* error */
goto done;
break;
}
/* There can be up to three more optional characters:
(1) A single '+' character,
(2) One of 'b' and 't' and
(3) One of 'c' and 'n'.
Note that currently, the 't' and 'b' flags are syntax checked
but ignored. 'c' and 'n', however, are correctly supported.
*/
whileflag=1;
tbflag=cnflag=0;
stream->_flag |= _commode;
while(*++mode && whileflag)
switch(*mode) {
case '+':
if (stream->_flag & _IORW)
whileflag=0;
else {
stream->_flag |= _IORW;
stream->_flag &= ~(_IOREAD | _IOWRT);
}
break;
case 'b':
case 't':
if (tbflag)
whileflag=0;
else
tbflag=1;
break;
case 'c':
if (cnflag)
whileflag = 0;
else {
cnflag = 1;
stream->_flag |= _IOCOMMIT;
}
break;
case 'n':
if (cnflag)
whileflag = 0;
else {
cnflag = 1;
stream->_flag &= ~_IOCOMMIT;
}
break;
default:
whileflag=0;
break;
}
_cflush++; /* force library pre-termination procedure */
stream->_file = filedes;
/* Common return */
done:
_unlock_str(index);
return(stream);
}
