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file.h
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2002-09-05
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/////////////////////////////////////////////////////////////////////////////
// Name: file.h
// Purpose: wxFile - encapsulates low-level "file descriptor"
// wxTempFile - safely replace the old file
// Author: Vadim Zeitlin
// Modified by:
// Created: 29/01/98
// RCS-ID: $Id: file.h,v 1.25 2002/09/04 22:17:09 VS Exp $
// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_FILEH__
#define _WX_FILEH__
#if defined(__GNUG__) && !defined(__APPLE__)
#pragma interface "file.h"
#endif
#ifndef WX_PRECOMP
#include "wx/string.h"
#include "wx/filefn.h"
#include "wx/strconv.h"
#endif
#if wxUSE_FILE
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
// we redefine these constants here because S_IREAD &c are _not_ standard
// however, we do assume that the values correspond to the Unix umask bits
#define wxS_IRUSR 00400
#define wxS_IWUSR 00200
#define wxS_IXUSR 00100
#define wxS_IRGRP 00040
#define wxS_IWGRP 00020
#define wxS_IXGRP 00010
#define wxS_IROTH 00004
#define wxS_IWOTH 00002
#define wxS_IXOTH 00001
// default mode for the new files: corresponds to umask 022
#define wxS_DEFAULT (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP |\
wxS_IROTH | wxS_IWOTH)
// ----------------------------------------------------------------------------
// class wxFile: raw file IO
//
// NB: for space efficiency this class has no virtual functions, including
// dtor which is _not_ virtual, so it shouldn't be used as a base class.
// ----------------------------------------------------------------------------
class WXDLLEXPORT wxFile
{
public:
// more file constants
// -------------------
// opening mode
enum OpenMode { read, write, read_write, write_append, write_excl };
// standard values for file descriptor
enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
// static functions
// ----------------
// check whether a regular file by this name exists
static bool Exists(const wxChar *name);
// check whetther we can access the given file in given mode
// (only read and write make sense here)
static bool Access(const wxChar *name, OpenMode mode);
// ctors
// -----
// def ctor
wxFile() { m_fd = fd_invalid; }
// open specified file (may fail, use IsOpened())
wxFile(const wxChar *szFileName, OpenMode mode = read);
// attach to (already opened) file
wxFile(int fd) { m_fd = fd; }
// open/close
// create a new file (with the default value of bOverwrite, it will fail if
// the file already exists, otherwise it will overwrite it and succeed)
bool Create(const wxChar *szFileName, bool bOverwrite = FALSE,
int access = wxS_DEFAULT);
bool Open(const wxChar *szFileName, OpenMode mode = read,
int access = wxS_DEFAULT);
bool Close(); // Close is a NOP if not opened
// assign an existing file descriptor and get it back from wxFile object
void Attach(int fd) { Close(); m_fd = fd; }
void Detach() { m_fd = fd_invalid; }
int fd() const { return m_fd; }
// read/write (unbuffered)
// returns number of bytes read or ofsInvalid on error
off_t Read(void *pBuf, off_t nCount);
// returns the number of bytes written
size_t Write(const void *pBuf, size_t nCount);
// returns true on success
bool Write(const wxString& s, wxMBConv& conv = wxConvLocal)
{
const wxWX2MBbuf buf = s.mb_str(conv);
size_t size = strlen(buf);
return Write((const char *) buf, size) == size;
}
// flush data not yet written
bool Flush();
// file pointer operations (return ofsInvalid on failure)
// move ptr ofs bytes related to start/current off_t/end of file
off_t Seek(off_t ofs, wxSeekMode mode = wxFromStart);
// move ptr to ofs bytes before the end
off_t SeekEnd(off_t ofs = 0) { return Seek(ofs, wxFromEnd); }
// get current off_t
off_t Tell() const;
// get current file length
off_t Length() const;
// simple accessors
// is file opened?
bool IsOpened() const { return m_fd != fd_invalid; }
// is end of file reached?
bool Eof() const;
// has an error occured?
bool Error() const { return m_error; }
// dtor closes the file if opened
~wxFile() { Close(); }
private:
// copy ctor and assignment operator are private because
// it doesn't make sense to copy files this way:
// attempt to do it will provoke a compile-time error.
wxFile(const wxFile&);
wxFile& operator=(const wxFile&);
int m_fd; // file descriptor or INVALID_FD if not opened
bool m_error; // error memory
};
// ----------------------------------------------------------------------------
// class wxTempFile: if you want to replace another file, create an instance
// of wxTempFile passing the name of the file to be replaced to the ctor. Then
// you can write to wxTempFile and call Commit() function to replace the old
// file (and close this one) or call Discard() to cancel the modification. If
// you call neither of them, dtor will call Discard().
// ----------------------------------------------------------------------------
class WXDLLEXPORT wxTempFile
{
public:
// ctors
// default
wxTempFile() { }
// associates the temp file with the file to be replaced and opens it
wxTempFile(const wxString& strName);
// open the temp file (strName is the name of file to be replaced)
bool Open(const wxString& strName);
// is the file opened?
bool IsOpened() const { return m_file.IsOpened(); }
// I/O (both functions return true on success, false on failure)
bool Write(const void *p, size_t n) { return m_file.Write(p, n) != 0; }
bool Write(const wxString& str, wxMBConv& conv = wxConvLibc) { return m_file.Write(str, conv); }
// different ways to close the file
// validate changes and delete the old file of name m_strName
bool Commit();
// discard changes
void Discard();
// dtor calls Discard() if file is still opened
~wxTempFile();
private:
// no copy ctor/assignment operator
wxTempFile(const wxTempFile&);
wxTempFile& operator=(const wxTempFile&);
wxString m_strName, // name of the file to replace in Commit()
m_strTemp; // temporary file name
wxFile m_file; // the temporary file
};
#endif // wxUSE_FILE
#endif // _WX_FILEH__