/***
*filebuf.cpp - core filebuf member functions
*
* Copyright (c) 1991-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Contains the core member functions for filebuf class.
*
*Revision History:
* 08-08-91 KRS Created.
* 08-20-91 KRS Added virtual xsgetn()/xsputn() functions.
* 08-21-91 KRS Fix circular reference between sync() and seekoff().
* Close file in destructor only if we opened it!
* 09-06-91 KRS Fix ios::ate case in filebuf::open().
* 09-09-91 KRS Add support for ios::binary in filebuf::open().
* 09-10-91 KRS Remove virtual xsputn()/xsgetn().
* 09-11-91 KRS Fix filebuf::seekoff() for ios::cur and in_avail().
* 09-12-91 KRS Make sure close() always closes even if sync() fails.
* Fix seekoff call in filebuf::sync() and pbackfail().
* 09-16-91 KRS Make virtual filebuf::setbuf() more robust.
* 09-19-91 KRS Add calls to delbuf(1) in constructors.
* 09-20-91 KRS C700 #4453: Improve efficiency in overflow().
* 09-29-91 KRS Granularity split. Move fstream into separate file.
* 10-24-91 KRS Avoid virtual calls from virtual functions.
* 11-13-91 KRS Use allocate() properly in overflow() and underflow().
* Fix constructor.
* 01-03-92 KRS Remove virtual keyword. Add function headers and PCH.
* 01-20-92 KRS In text mode, account for CR/LF pairs in sync().
* 02-03-92 KRS Change for new compiler destructor behavior.
* 08-19-92 KRS Remove sh_compat for NT.
* 08-27-92 KRS Fix bug in close() introduced in MTHREAD work.
* 02-23-95 CFW Fix bug: buffer overwritten when disk full.
* 06-14-95 CFW Comment cleanup.
* 06-19-95 GJF Replaced _osfile[] with _osfile() (which references
* a field in the ioinfo struct).
* 05-17-99 PML Remove all Macintosh support.
*
*******************************************************************************/
#include <cruntime.h>
#include <internal.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <crtdbg.h>
#include <sys\types.h>
#include <io.h>
#include <fstream.h>
#pragma hdrstop
#include <msdos.h>
#include <sys\stat.h>
const int filebuf::openprot = 0644;
const int filebuf::sh_none = 04000; // deny rw
const int filebuf::sh_read = 05000; // deny wr
const int filebuf::sh_write = 06000; // deny rd
const int filebuf::binary = O_BINARY;
const int filebuf::text = O_TEXT;
/***
*filebuf::filebuf() - filebuf default constructor
*
*Purpose:
* Default constructor.
*
*Entry:
*
*******************************************************************************/
filebuf::filebuf()
: streambuf()
{
x_fOpened = 0;
x_fd = -1;
}
/***
*filebuf::filebuf(filedesc fd) - filebuf constructor
*
*Purpose:
* Constructor. Initialize filebuf and attach to file descriptor.
*
*Entry:
* fd = file descriptor to attach to filebuf
*
*******************************************************************************/
filebuf::filebuf(filedesc fd)
: streambuf()
{
x_fOpened = 0;
x_fd=fd;
}
/***
*filebuf::filebuf(filedesc fd, char* p, int len) - filebuf constructor
*
*Purpose:
* Constructor. Initialize filebuf and attach to file descriptor.
*
*Entry:
* fd = file descriptor to attach to filebuf
* p = user-supplied buffer
* len = length of buffer
*
*******************************************************************************/
filebuf::filebuf(filedesc fd, char* p, int len)
: streambuf()
{
filebuf::setbuf(p,len);
x_fOpened = 0;
x_fd=fd;
}
/***
*filebuf::~filebuf() - filebuf destructor
*
*Purpose:
* Destructor. Close attached file only if we opened it.
*
*Entry:
* None.
*
*******************************************************************************/
filebuf::~filebuf()
{
lock(); // no need to unlock...
if (x_fOpened)
close(); // calls filebuf::sync()
else
filebuf::sync();
}
/***
*filebuf* filebuf::close() - close an attached file
*
*Purpose:
* Close attached file.
*
*Entry:
* None.
*Exit:
* Returns NULL if error, otherwise returns "this" pointer.
*
*******************************************************************************/
filebuf* filebuf::close()
{
int retval;
if (x_fd==-1)
return NULL;
lock();
retval = sync();
if ((_close(x_fd)==-1) || (retval==EOF))
{
unlock();
return NULL;
}
x_fd = -1;
unlock();
return this;
}
/***
*virtual int filebuf::overflow(int c) - overflow virtual function
*
*Purpose:
* flush any characters in the reserve area and handle 'c'.
*
*Entry:
* c = character to output (if not EOF)
*
*Exit:
* Returns EOF if error, otherwise returns something else.
*
*Exceptions:
* Returns EOF if error.
*
*******************************************************************************/
int filebuf::overflow(int c)
{
if (allocate()==EOF) // make sure there is a reserve area
return EOF;
if (filebuf::sync()==EOF) // sync before new buffer created below
return EOF;
if (!unbuffered())
setp(base(),ebuf());
if (c!=EOF)
{
if ((!unbuffered()) && (pptr() < epptr())) // guard against recursion
sputc(c);
else
{
if (_write(x_fd,&c,1)!=1)
return(EOF);
}
}
return(1); // return something other than EOF if successful
}
/***
*virtual int filebuf::underflow() - underflow virtual function
*
*Purpose:
* return next character in get area, or get more characters from source.
*
*Entry:
* None.
*
*Exit:
* Returns current character in file. Does not advance get pointer.
*
*Exceptions:
* Returns EOF if error.
*
*******************************************************************************/
int filebuf::underflow()
{
int count;
unsigned char tbuf;
if (in_avail())
return (int)(unsigned char) *gptr();
if (allocate()==EOF) // make sure there is a reserve area
return EOF;
if (filebuf::sync()==EOF)
return EOF;
if (unbuffered())
{
if (_read(x_fd,(void *)&tbuf,1)<=0)
return EOF;
return (int)tbuf;
}
if ((count=_read(x_fd,(void *)base(),blen())) <= 0)
return EOF; // reached EOF
setg(base(),base(),base()+count);
return (int)(unsigned char) *gptr();
}
/***
*virtual streampos filebuf::seekoff() - seekoff virtual function
*
*Purpose:
* Seeks to given absolute or relative file offset.
*
*Entry:
* off = offset to seek to relative to beginning, end or current
* position in the file.
* dir = one of ios::beg, ios::cur, or ios::end
*
*Exit:
* Returns current file position after seek.
*
*Exceptions:
* Returns EOF if error.
*
*******************************************************************************/
streampos filebuf::seekoff(streamoff off, ios::seek_dir dir, int)
{
int fdir;
long retpos;
switch (dir) {
case ios::beg :
fdir = SEEK_SET;
break;
case ios::cur :
fdir = SEEK_CUR;
break;
case ios::end :
fdir = SEEK_END;
break;
default:
// error
return(EOF);
}
if (filebuf::sync()==EOF)
return EOF;
if ((retpos=_lseek(x_fd, off, fdir))==-1L)
return (EOF);
return((streampos)retpos);
}
/***
*virtual int filebuf::sync() - synchronize buffers with external file postion.
*
*Purpose:
* Synchronizes buffer with external file, by flushing any output and/or
* discarding any unread input data. Discards any get or put area(s).
*
*Entry:
* None.
*
*Exit:
* Returns EOF if error, else 0.
*
*Exceptions:
* Returns EOF if error.
*
*******************************************************************************/
int filebuf::sync()
{
long count, nout;
char * p;
if (x_fd==-1)
return(EOF);
if (!unbuffered())
{
if ((count=out_waiting())!=0)
{
if ((nout =_write(x_fd,(void *) pbase(),(unsigned int)count)) != count)
{
if (nout > 0) {
// should set _pptr -= nout
pbump(-(int)nout);
memmove(pbase(), pbase()+nout, (int)(count-nout));
}
return(EOF);
}
}
setp(0,0); // empty put area
if ((count=in_avail()) > 0)
{
// can't use seekoff here!!
if (_osfile(x_fd) & FTEXT)
{
// If text mode, need to account for CR/LF etc.
for (p = gptr(); p < egptr(); p++)
if (*p == '\n')
count++;
// account for EOF if read, not counted by _read
if ((_osfile(x_fd) & FEOFLAG))
count++;
}
if (_lseek(x_fd, -count, SEEK_CUR)==-1L)
{
// unlock();
return (EOF);
}
}
setg(0,0,0); // empty get area
}
// unlock();
return(0);
}
/***
*virtual streambuf* filebuf::setbuf(char* ptr, int len) - set reserve area.
*
*Purpose:
* Synchronizes buffer with external file, by flushing any output and/or
* discarding any unread input data. Discards any get or put area(s).
*
*Entry:
* ptr = requested reserve area. If NULL, request is for unbuffered.
* len = size of reserve area. If <= 0, request is for unbuffered.
*
*Exit:
* Returns this pointer if request is honored, else NULL.
*
*Exceptions:
* Returns NULL if request is not honored.
*
*******************************************************************************/
streambuf * filebuf::setbuf(char * ptr, int len)
{
if (is_open() && (ebuf()))
return NULL;
if ((!ptr) || (len <= 0))
unbuffered(1);
else
{
lock();
setb(ptr, ptr+len, 0);
unlock();
}
return this;
}