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-rw-r--r--private/crt32/iostream/filebuf.cxx460
1 files changed, 460 insertions, 0 deletions
diff --git a/private/crt32/iostream/filebuf.cxx b/private/crt32/iostream/filebuf.cxx
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+/***
+*filebuf.cxx - core filebuf member functions
+*
+* Copyright (c) 1991-1992, 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.
+*
+*******************************************************************************/
+
+#include <cruntime.h>
+#include <internal.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.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; // CONSIDER: meaning?
+
+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(); // CONSIDER: possible recursion
+}
+
+
+/***
+*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);
+}
+
+/* NOT IN SPEC.
+int filebuf::pbackfail(int c)
+{
+ if (eback()<gptr()) return sputbackc(c); // CONSIDER: should never happen
+
+ if (filebuf::seekoff( -1, ios::cur, ios::in)==EOF)
+ return EOF;
+ if (!unbuffered())
+ filebuf::underflow();
+ // assert c = underflow()
+ }
+ return(c);
+}
+*/
+
+#if 0
+// NOT IN SPEC.
+// UNDONE: consider removing this?
+int filebuf::xsgetn(char * ptr, int n)
+{
+ int retval;
+ int oldmode;
+
+ if (x_fd==-1)
+ return 0;
+ if (filebuf::sync()!=EOF)
+ {
+ // set to BINARY and save old mode.
+ oldmode = _setmode(x_fd,O_BINARY);
+ }
+ retval = sgetn(ptr,n);
+ filebuf::sync(); // put back any excess (ignore errors)
+
+ if (oldmode==O_TEXT) // check != -1
+ {
+ _setmode(x_fd,oldmode);
+ }
+ return retval;
+}
+
+// NOT IN SPEC.
+// UNDONE: consider removing this?
+int filebuf::xsputn(const char * ptr, int n)
+{
+ int retval;
+ int oldmode;
+
+ if (x_fd==-1)
+ return 0;
+ if (filebuf::sync()!=EOF)
+ {
+ // set to BINARY and save old mode.
+ oldmode = _setmode(x_fd,O_BINARY);
+ }
+
+ retval = sputn(ptr,n);
+ filebuf::sync(); // flush output;
+
+ if (oldmode==O_TEXT) // check != -1
+ {
+ _setmode(x_fd,oldmode);
+ }
+ return retval;
+}
+#endif
+
+
+/***
+*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);
+// lock(); // CONSIDER: do we need/want locking here?
+ if (!unbuffered())
+ {
+ if ((count=out_waiting())!=0)
+ {
+ if ((nout =_write(x_fd,(void *) pbase(),(unsigned int)count)) != count)
+ {
+ // should set _pptr -= nout
+ pbump(-(int)nout);
+ memmove(pbase(), pbase()+nout, (int)(count-nout));
+// unlock();
+ 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
+ // UNDONE: is this necessary / useful?
+ if ((_osfile[x_fd] & FEOFLAG))
+ count++;
+#if 0
+ // UNDONE: is this correct?
+ if ((gptr()==eback()) && (_osfile[x_fd] & FCRLF))
+ count--;
+#endif
+ }
+ 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(); // consider: necessary?
+ setb(ptr, ptr+len, 0);
+ unlock();
+ }
+ return this;
+}
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