Exiv2::FileIo Class Reference

Provides binary file IO by implementing the BasicIo interface. More...

#include <basicio.hpp>

Inheritance diagram for Exiv2::FileIo:

Public Member Functions

Creators
 FileIo (const std::string &path)
 Constructor that accepts the file path on which IO will be performed. The constructor does not open the file, and therefore never failes. More...
 
virtual ~FileIo ()
 Destructor. Flushes and closes an open file.
 
Manipulators
int open (const std::string &mode)
 Open the file using using the specified mode. More...
 
virtual int open ()
 Open the file using using the default access mode of "rb". This method can also be used to "reopen" a file which will flush any unwritten data and reset the IO position to the start. More...
 
virtual int close ()
 Flush and unwritten data and close the file . It is safe to call close on an already closed instance. More...
 
virtual long write (const byte *data, long wcount)
 Write data to the file. The file position is advanced by the number of bytes written. More...
 
virtual long write (BasicIo &src)
 Write data that is read from another BasicIo instance to the file. The file position is advanced by the number of bytes written. More...
 
virtual int putb (byte data)
 Write one byte to the file. The file position is advanced by one byte. More...
 
virtual DataBuf read (long rcount)
 Read data from the file. Reading starts at the current file position and the position is advanced by the number of bytes read. More...
 
virtual long read (byte *buf, long rcount)
 Read data from the file. Reading starts at the current file position and the position is advanced by the number of bytes read. More...
 
virtual int getb ()
 Read one byte from the file. The file position is advanced by one byte. More...
 
virtual void transfer (BasicIo &src)
 Remove the contents of the file and then transfer data from the src BasicIo object into the empty file. More...
 
virtual int seek (long offset, Position pos)
 Move the current file position. More...
 
virtual bytemmap (bool isWriteable=false)
 Map the file into the process's address space. The file must be open before mmap() is called. If the mapped area is writeable, changes may not be written back to the underlying file until munmap() is called. The pointer is valid only as long as the FileIo object exists. More...
 
virtual int munmap ()
 Remove a mapping established with mmap(). If the mapped area is writeable, this ensures that changes are written back to the underlying file. More...
 
virtual void setPath (const std::string &path)
 close the file source and set a new path.
 
Accessors
virtual long tell () const
 Get the current file position. More...
 
virtual long size () const
 Flush any buffered writes and get the current file size in bytes. More...
 
virtual bool isopen () const
 Returns true if the file is open, otherwise false.
 
virtual int error () const
 Returns 0 if the file is in a valid state, otherwise nonzero.
 
virtual bool eof () const
 Returns true if the file position has reach the end, otherwise false.
 
virtual std::string path () const
 Returns the path of the file.
 
virtual BasicIo::AutoPtr temporary () const
 Returns a temporary data storage location. The actual type returned depends upon the size of the file represented a FileIo object. For small files, a MemIo is returned while for large files a FileIo is returned. Callers should not rely on this behavior, however, since it may change. More...
 
virtual void populateFakeData ()
 Mark all the bNone blocks to bKnow. This avoids allocating memory for parts of the file that contain image-date (non-metadata/pixel data) More...
 
- Public Member Functions inherited from Exiv2::BasicIo
virtual ~BasicIo ()
 Destructor.
 

Additional Inherited Members

- Public Types inherited from Exiv2::BasicIo
enum  Position { beg, cur, end }
 Seek starting positions.
 
typedef std::auto_ptr< BasicIoAutoPtr
 BasicIo auto_ptr type.
 
- Protected Member Functions inherited from Exiv2::BasicIo
 BasicIo ()
 Default Constructor.
 

Detailed Description

Provides binary file IO by implementing the BasicIo interface.

Constructor & Destructor Documentation

Exiv2::FileIo::FileIo ( const std::string &  path)

Constructor that accepts the file path on which IO will be performed. The constructor does not open the file, and therefore never failes.

Parameters
pathThe full path of a file

Member Function Documentation

virtual int Exiv2::FileIo::close ( )
virtual

Flush and unwritten data and close the file . It is safe to call close on an already closed instance.

Returns
0 if successful;
Nonzero if failure;

Implements Exiv2::BasicIo.

virtual int Exiv2::FileIo::getb ( )
virtual

Read one byte from the file. The file position is advanced by one byte.

Returns
The byte read from the file if successful;
EOF if failure;

Implements Exiv2::BasicIo.

virtual byte* Exiv2::FileIo::mmap ( bool  isWriteable = false)
virtual

Map the file into the process's address space. The file must be open before mmap() is called. If the mapped area is writeable, changes may not be written back to the underlying file until munmap() is called. The pointer is valid only as long as the FileIo object exists.

Parameters
isWriteableSet to true if the mapped area should be writeable (default is false).
Returns
A pointer to the mapped area.
Exceptions
ErrorIn case of failure.

Implements Exiv2::BasicIo.

virtual int Exiv2::FileIo::munmap ( )
virtual

Remove a mapping established with mmap(). If the mapped area is writeable, this ensures that changes are written back to the underlying file.

Returns
0 if successful;
Nonzero if failure;

Implements Exiv2::BasicIo.

int Exiv2::FileIo::open ( const std::string &  mode)

Open the file using using the specified mode.

This method can also be used to "reopen" a file which will flush any unwritten data and reset the IO position to the start. Although files can be opened in binary or text mode, this class has only been tested carefully in binary mode.

Parameters
modeSpecified that type of access allowed on the file. Valid values match those of the C fopen command exactly.
Returns
0 if successful;
Nonzero if failure.
virtual int Exiv2::FileIo::open ( )
virtual

Open the file using using the default access mode of "rb". This method can also be used to "reopen" a file which will flush any unwritten data and reset the IO position to the start.

Returns
0 if successful;
Nonzero if failure.

Implements Exiv2::BasicIo.

virtual void Exiv2::FileIo::populateFakeData ( )
virtual

Mark all the bNone blocks to bKnow. This avoids allocating memory for parts of the file that contain image-date (non-metadata/pixel data)

Note
This method should be only called after the concerned data (metadata) are all downloaded from the remote file to memory.

Reimplemented from Exiv2::BasicIo.

virtual int Exiv2::FileIo::putb ( byte  data)
virtual

Write one byte to the file. The file position is advanced by one byte.

Parameters
dataThe single byte to be written.
Returns
The value of the byte written if successful;
EOF if failure;

Implements Exiv2::BasicIo.

virtual DataBuf Exiv2::FileIo::read ( long  rcount)
virtual

Read data from the file. Reading starts at the current file position and the position is advanced by the number of bytes read.

Parameters
rcountMaximum number of bytes to read. Fewer bytes may be read if rcount bytes are not available.
Returns
DataBuf instance containing the bytes read. Use the DataBuf::size_ member to find the number of bytes read. DataBuf::size_ will be 0 on failure.

Implements Exiv2::BasicIo.

virtual long Exiv2::FileIo::read ( byte buf,
long  rcount 
)
virtual

Read data from the file. Reading starts at the current file position and the position is advanced by the number of bytes read.

Parameters
bufPointer to a block of memory into which the read data is stored. The memory block must be at least rcount bytes long.
rcountMaximum number of bytes to read. Fewer bytes may be read if rcount bytes are not available.
Returns
Number of bytes read from the file successfully;
0 if failure;

Implements Exiv2::BasicIo.

virtual int Exiv2::FileIo::seek ( long  offset,
Position  pos 
)
virtual

Move the current file position.

Parameters
offsetNumber of bytes to move the file position relative to the starting position specified by pos
posPosition from which the seek should start
Returns
0 if successful;
Nonzero if failure;

Implements Exiv2::BasicIo.

virtual long Exiv2::FileIo::size ( ) const
virtual

Flush any buffered writes and get the current file size in bytes.

Returns
Size of the file in bytes;
-1 if failure;

Implements Exiv2::BasicIo.

virtual long Exiv2::FileIo::tell ( ) const
virtual

Get the current file position.

Returns
Offset from the start of the file if successful;
-1 if failure;

Implements Exiv2::BasicIo.

virtual BasicIo::AutoPtr Exiv2::FileIo::temporary ( ) const
virtual

Returns a temporary data storage location. The actual type returned depends upon the size of the file represented a FileIo object. For small files, a MemIo is returned while for large files a FileIo is returned. Callers should not rely on this behavior, however, since it may change.

Returns
An instance of BasicIo on success
Exceptions
ErrorIf opening the temporary file fails

Implements Exiv2::BasicIo.

virtual void Exiv2::FileIo::transfer ( BasicIo src)
virtual

Remove the contents of the file and then transfer data from the src BasicIo object into the empty file.

This method is optimized to simply rename the source file if the source object is another FileIo instance. The source BasicIo object is invalidated by this operation and should not be used after this method returns. This method exists primarily to be used with the BasicIo::temporary() method.

Note
If the caller doesn't have permissions to write to the file, an exception is raised and src is deleted.
Parameters
srcReference to another BasicIo instance. The entire contents of src are transferred to this object. The src object is invalidated by the method.
Exceptions
ErrorIn case of failure

Implements Exiv2::BasicIo.

Reimplemented in Exiv2::XPathIo.

virtual long Exiv2::FileIo::write ( const byte data,
long  wcount 
)
virtual

Write data to the file. The file position is advanced by the number of bytes written.

Parameters
dataPointer to data. Data must be at least wcount bytes long
wcountNumber of bytes to be written.
Returns
Number of bytes written to the file successfully;
0 if failure;

Implements Exiv2::BasicIo.

virtual long Exiv2::FileIo::write ( BasicIo src)
virtual

Write data that is read from another BasicIo instance to the file. The file position is advanced by the number of bytes written.

Parameters
srcReference to another BasicIo instance. Reading start at the source's current IO position
Returns
Number of bytes written to the file successfully;
0 if failure;

Implements Exiv2::BasicIo.


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