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NAME

       ost::RandomFile -

       The purpose of this class is to define a base class for low level
       random file access that is portable between Win32 and Posix systems.

SYNOPSIS

       #include <file.h>

       Inherits ost::Mutex, and ost::File.

       Inherited by ost::MappedFile, ost::SharedFile, and ost::ThreadFile.

   Public Member Functions
       virtual ~RandomFile ()
           Destroy a random access file or its derived class.
       bool initial (void)
           This method should be called right after a RandomFile derived
           object has been created.
       off_t getCapacity (void)
           Get current file capacity.
       virtual Error restart (void)
           This method is commonly used to close and re-open an existing
           database.
       Error getErrorNumber (void)
           Return current error id.
       char * getErrorString (void)
           Return current error string.
       bool operator! (void)

   Protected Member Functions
       RandomFile (const char *name=NULL)
           Create an unopened random access file.
       RandomFile (const RandomFile &rf)
           Default copy constructor.
       Error error (Error errid, char *errstr=NULL)
           Post an error event.
       Error error (char *err)
           Post an extended string error message.
       void setError (bool enable)
           Used to enable or disable throwing of exceptions on errors.
       Error setCompletion (Complete mode)
           Used to set file completion modes.
       void setTemporary (bool enable)
           Used to set the temporary attribute for the file.
       virtual Attr initialize (void)
           This method is used to initialize a newly created file as indicated
           by the initial flag.
       void final (void)
           Close the file.

   Protected Attributes
       int fd
       Access access
       char * pathname
       struct {
          unsigned count: 16
          bool thrown: 1
          bool initial: 1
          bool immediate: 1
          bool temp: 1
       } flags

   Related Functions
       (Note that these are not member functions.)
       bool isDir (const char *path)
       bool isFile (const char *path)
       bool isDevice (const char *path)
       bool canAccess (const char *path)
       bool canModify (const char *path)
       time_t lastModified (const char *path)
       time_t lastAccessed (const char *path)

Detailed Description

       The purpose of this class is to define a base class for low level
       random file access that is portable between Win32 and Posix systems.

       This class is a foundation both for optimized thread shared and
       traditional locked file access that is commonly used to build database
       services, rather than the standard C++ streaming file classes.

       Author:
           David Sugar <dyfet@ostel.com> Portable random disk file access.

Constructor & Destructor Documentation

   ost::RandomFile::RandomFile (const char * name = NULL) [protected]
       Create an unopened random access file.

   ost::RandomFile::RandomFile (const RandomFile & rf) [protected]
       Default copy constructor.

   virtual ost::RandomFile::~RandomFile () [virtual]
       Destroy a random access file or it’s derived class.

Member Function Documentation

   Error ost::RandomFile::error (char * err) [inline, protected]
       Post an extended string error message. Returns:
           errExtended.

       Parameters:
           err error string.

       References error().

       Referenced by error().

   Error ost::RandomFile::error (Error errid, char * errstr = NULL)
       [protected]
       Post an error event. Returns:
           error code.

       Parameters:
           errid error code.
           errstr error message string.

   void ost::RandomFile::final (void) [protected]
       Close the file.

   off_t ost::RandomFile::getCapacity (void)
       Get current file capacity. Returns:
           total file size.

   Error ost::RandomFile::getErrorNumber (void) [inline]
       Return current error id. Returns:
           last error identifier set.

   char* ost::RandomFile::getErrorString (void) [inline]
       Return current error string. Returns:
           last error string set.

   bool ost::RandomFile::initial (void)
       This method should be called right after a RandomFile derived object
       has been created. This method will invoke initialize if the object is
       newly created, and set file access permissions appropriately.

       Returns:
           true if file had to be initialized.

   virtual Attr ost::RandomFile::initialize (void) [protected, virtual]
       This method is used to initialize a newly created file as indicated by
       the ’initial’ flag. This method also returns the file access
       permissions that should be associated with the file. This method should
       never be called directly, but is instead used to impliment the
       ’Initial’ method. Typically one would use this to build an empty
       database shell when a previously empty database file is created.

       Returns:
           access, or attrInvalid if should be removed.

   bool ost::RandomFile::operator! (void)
   virtual Error ost::RandomFile::restart (void) [virtual]
       This method is commonly used to close and re-open an existing database.
       This may be used when the database has been unlinked and an external
       process provides a new one to use.

       Reimplemented in ost::ThreadFile, and ost::SharedFile.

   Error ost::RandomFile::setCompletion (Complete mode) [protected]
       Used to set file completion modes. Returns:
           errSuccess if okay.

       Parameters:
           mode completion mode.

   void ost::RandomFile::setError (bool enable) [inline, protected]
       Used to enable or disable throwing of exceptions on errors. Parameters:
           enable true if errors will be thrown.

   void ost::RandomFile::setTemporary (bool enable) [inline, protected]
       Used to set the temporary attribute for the file. Temporary files are
       automatically deleted when closed.

       Parameters:
           enable true for marking as temporary.

Friends And Related Function Documentation

   bool canAccess (const char * path) [related]
   bool canModify (const char * path) [related]
   bool isDevice (const char * path) [related]
   bool isDir (const char * path) [related]
   bool isFile (const char * path) [related]
   time_t lastAccessed (const char * path) [related]
   time_t lastModified (const char * path) [related]

Member Data Documentation

   Access ost::RandomFile::access [protected]
   unsigned ost::RandomFile::count
   int ost::RandomFile::fd [protected]
   struct { ... }   ost::RandomFile::flags [protected]
   bool ost::RandomFile::immediate
   bool ost::RandomFile::initial
   char* ost::RandomFile::pathname [protected]
   bool ost::RandomFile::temp
   bool ost::RandomFile::thrown

Author

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