Exiv2::RemoteIo Class Reference

Provides remote binary file IO by implementing the BasicIo interface. This is an abstract class. The logics for remote access are implemented in HttpIo, CurlIo, SshIo which are the derived classes of RemoteIo. More...

#include <basicio.hpp>

Inheritance diagram for Exiv2::RemoteIo:

Public Member Functions

virtual ~RemoteIo ()
 Destructor. Releases all managed memory.
 
Manipulators
virtual int open ()
 Connect to the remote server, get the size of the remote file and allocate the array of blocksMap. More...
 
virtual int close ()
 Reset the IO position to the start. It does not release the data. More...
 
virtual long write (const byte *data, long wcount)
 Not support this method. More...
 
virtual long write (BasicIo &src)
 Write data that is read from another BasicIo instance to the remote file. More...
 
virtual int putb (byte data)
 Not support. More...
 
virtual DataBuf read (long rcount)
 Read data from the memory blocks. Reading starts at the current IO position and the position is advanced by the number of bytes read. If the memory blocks are not populated (False), it will connect to server and populate the data to memory blocks. More...
 
virtual long read (byte *buf, long rcount)
 Read data from the the memory blocks. Reading starts at the current IO position and the position is advanced by the number of bytes read. If the memory blocks are not populated (!= bMemory), it will connect to server and populate the data to memory blocks. More...
 
virtual int getb ()
 Read one byte from the memory blocks. The IO position is advanced by one byte. If the memory block is not populated (!= bMemory), it will connect to server and populate the data to the memory block. 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 IO position. More...
 
virtual bytemmap (bool=false)
 Not support. More...
 
virtual int munmap ()
 Not support. More...
 
Accessors
virtual long tell () const
 Get the current IO position. More...
 
virtual size_t size () const
 Get the current memory buffer size in bytes. More...
 
virtual bool isopen () const
 Returns true if the memory area is allocated.
 
virtual int error () const
 Always returns 0.
 
virtual bool eof () const
 Returns true if the IO position has reached the end, otherwise false.
 
virtual std::string path () const
 Returns the URL of the file.
 
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.
 

Protected Member Functions

Creators
 RemoteIo ()
 Default Constructor.
 
- Protected Member Functions inherited from Exiv2::BasicIo
 BasicIo ()
 Default Constructor.
 

Protected Attributes

Impl * p_
 Pointer to implementation.
 

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.
 
- Public Attributes inherited from Exiv2::BasicIo
bytebigBlock_
 this is allocated and populated by mmap()
 

Detailed Description

Provides remote binary file IO by implementing the BasicIo interface. This is an abstract class. The logics for remote access are implemented in HttpIo, CurlIo, SshIo which are the derived classes of RemoteIo.

Member Function Documentation

◆ close()

virtual int Exiv2::RemoteIo::close ( )
virtual

Reset the IO position to the start. It does not release the data.

Returns
0 if successful;
Nonzero if failure.

Implements Exiv2::BasicIo.

◆ getb()

virtual int Exiv2::RemoteIo::getb ( )
virtual

Read one byte from the memory blocks. The IO position is advanced by one byte. If the memory block is not populated (!= bMemory), it will connect to server and populate the data to the memory block.

Returns
The byte read from the memory block if successful;
EOF if failure;

Implements Exiv2::BasicIo.

◆ mmap()

virtual byte* Exiv2::RemoteIo::mmap ( bool  = false)
virtual

Not support.

Returns
NULL

Implements Exiv2::BasicIo.

◆ munmap()

virtual int Exiv2::RemoteIo::munmap ( )
virtual

Not support.

Returns
0

Implements Exiv2::BasicIo.

◆ open()

virtual int Exiv2::RemoteIo::open ( )
virtual

Connect to the remote server, get the size of the remote file and allocate the array of blocksMap.

If the blocksMap is already allocated (this method has been called before), it just reset IO position to the start and does not flush the old data.

Returns
0 if successful;
Nonzero if failure.

Implements Exiv2::BasicIo.

◆ populateFakeData()

virtual void Exiv2::RemoteIo::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.

◆ putb()

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

Not support.

Returns
0 means failure

Implements Exiv2::BasicIo.

◆ read() [1/2]

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

Read data from the memory blocks. Reading starts at the current IO position and the position is advanced by the number of bytes read. If the memory blocks are not populated (False), it will connect to server and populate the data to memory blocks.

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.

◆ read() [2/2]

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

Read data from the the memory blocks. Reading starts at the current IO position and the position is advanced by the number of bytes read. If the memory blocks are not populated (!= bMemory), it will connect to server and populate the data to memory blocks.

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 memory block successfully;
0 if failure;

Implements Exiv2::BasicIo.

◆ seek()

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

Move the current IO position.

Parameters
offsetNumber of bytes to move the IO 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.

◆ size()

virtual size_t Exiv2::RemoteIo::size ( ) const
virtual

Get the current memory buffer size in bytes.

Returns
Size of the in memory data in bytes;
-1 if failure;

Implements Exiv2::BasicIo.

◆ tell()

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

Get the current IO position.

Returns
Offset from the start of the memory block

Implements Exiv2::BasicIo.

◆ transfer()

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

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

The write access is done in an efficient way. It only sends the range of different bytes between the current data and BasicIo instance to the remote machine.

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
Note
The write access is only supported by http, https, ssh.

Implements Exiv2::BasicIo.

◆ write() [1/2]

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

Not support this method.

Returns
0 means failure

Implements Exiv2::BasicIo.

◆ write() [2/2]

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

Write data that is read from another BasicIo instance to the remote file.

The write access is done in an efficient way. It only sends the range of different bytes between the current data and BasicIo instance to the remote machine.

Parameters
srcReference to another BasicIo instance. Reading start at the source's current IO position
Returns
The size of BasicIo instance;
0 if failure;
Exceptions
ErrorIn case of failure
Note
The write access is only supported by http, https, ssh.

Implements Exiv2::BasicIo.


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