IO Class Reference

IO is the base class for binary input and output. More...

#include <IO.h>

Inheritance diagram for IO:
Object FileIO

List of all members.

Classes

struct  Location
 Location is a helper structure for holding the location of data in a IO object. More...

Public Types

typedef lt_int64 offset_type
 Integer data type for file offsets and sizes.

Public Member Functions

void open (void)
 Open the IO object.
void close (void)
 Close the IO object.
virtual size_t pread (offset_type offset, void *buffer, size_t nbytes) const =0
 Read data.
virtual size_t pwrite (offset_type offset, const void *buffer, size_t nbytes) const =0
 Write data.
virtual offset_type size (void) const =0
 Get the size of the resource.
virtual void truncate (offset_type length)=0
 Set the size of the resource.
virtual void unlink (void)=0
 Delete the resource when the IO object is deleted.

Protected Member Functions

virtual void popen (void)=0
 The Real Open.
virtual void pclose (void)=0
 The Real Close.

Detailed Description

The IO class was designed to thread safe for reading and writing. The reading and writing functions do not have a internal file position, the offset is passed into pread() and pwrite(). This is based off the POSIX pread() and pwrite() interfaces. Unlike the libc's FILE structure the buffering is not part of the IO object. Buffering is handled by the StreamReader and the StreamWriter classes.

Definition at line 30 of file IO.h.


Member Typedef Documentation

Definition at line 37 of file IO.h.


Member Function Documentation

void IO::close ( void   ) 

This method closes the IO object. open() and close() are reference counted so you must call close() the some number of times as open().

void IO::open ( void   ) 

This method opens the IO object. open() and close() are reference counted so you must call close() the some number of times as open().

virtual void IO::pclose ( void   )  [protected, pure virtual]

This method gets called by close() when the resource needs to be closed.

virtual void IO::popen ( void   )  [protected, pure virtual]

This method gets called by open() when the resource needs to be opened.

virtual size_t IO::pread ( offset_type  offset,
void *  buffer,
size_t  nbytes 
) const [pure virtual]

This method tries to read nbytes bytes at the given offset.

Parameters:
offset the file offset to read from
buffer the destination memory location
nbytes the number of bytes to read
Returns:
the number of bytes read
virtual size_t IO::pwrite ( offset_type  offset,
const void *  buffer,
size_t  nbytes 
) const [pure virtual]

This method tries to write nbytes bytes at the given offset.

Parameters:
offset the file offset to write to
buffer the source memory location
nbytes the number of bytes to write
Returns:
the number of bytes written
virtual offset_type IO::size ( void   )  const [pure virtual]

This method returns the size of the resource.

virtual void IO::truncate ( offset_type  length  )  [pure virtual]

This method sets the size of the resource. If the new size is smaller the data is lost. If the new size is larger the resource padded with zeros.

Note:
The object must be open.
virtual void IO::unlink ( void   )  [pure virtual]

This method marks the resource for deletion when the object goes away.

Implemented in FileIO.


The documentation for this class was generated from the following file:

LizardTech