LTIOFileStream Class Reference

File stream. More...

#include <lt_ioFileStream.h>

Inheritance diagram for LTIOFileStream:

LTIOStreamInf

List of all members.

Public Member Functions

virtual bool isEOF ()
 Test for end-of-stream.
virtual bool isOpen ()
 Test for stream openness.
virtual LT_STATUS open ()
 Opens the stream.
virtual LT_STATUS close ()
 Closes the stream.
virtual lt_uint32 read (lt_uint8 *pDest, lt_uint32 numBytes)
 Retrieve the specified number of bytes from the data source and place them in pDest.
virtual lt_uint32 write (const lt_uint8 *pSrc, lt_uint32 numBytes)
 Store the specified number of bytes in the data source.
virtual LT_STATUS seek (lt_int64 offset, LTIOSeekDir origin)
 Moves the data access position to origin + offset.
virtual lt_int64 tell ()
 Returns the current data access position as an offset from the start of the data.
virtual LTIOStreamInfduplicate ()
 Clone the stream.
virtual LT_STATUS getLastError () const
 Get status code of last error event.
virtual const char * getID () const
 Get a URI describing the stream object.
int stdio_setvbuf (lt_uint8 *buf, lt_uint32 mode, lt_uint32 size)
 Set buffering - may be called only after open() but before the first read/write operation.
Construction, destruction, initialization
 LTIOFileStream (void)
 Default Constructor.
virtual ~LTIOFileStream (void)
 Destructor.
virtual LT_STATUS initialize (const LTFileSpec &fs, const char *mode)
 Initializes the stream from a file spec.
LT_STATUS initialize (const char *path, const char *mode)
 Default Constructor.
Status accessors
int stdio_ferror ()
 Returns underlying stdio error code.
void stdio_clearerr ()
 Clears underlying stdio error code.

Protected Types

enum  { unknown_state = 1, reading_state = 2, writing_state = 3 }

Protected Attributes

FILE * m_file
enum LTIOFileStream:: { ... }  m_state
LTFileSpec m_path
char * m_mode
char * m_uri


Detailed Description

This class implements a file-based stream.
Examples:

DerivedImageReader.cpp, and UsingStreams.cpp.

Definition at line 33 of file lt_ioFileStream.h.


Member Enumeration Documentation

anonymous enum [protected]

Enumerator:
unknown_state 
reading_state 
writing_state 

Definition at line 114 of file lt_ioFileStream.h.


Constructor & Destructor Documentation

LTIOFileStream::LTIOFileStream ( void   ) 

virtual LTIOFileStream::~LTIOFileStream ( void   )  [virtual]


Member Function Documentation

virtual LT_STATUS LTIOFileStream::initialize ( const LTFileSpec fs,
const char *  mode 
) [virtual]

Parameters:
fs file spec
mode mode (see stdio.h)
Examples:
UsingStreams.cpp.

LT_STATUS LTIOFileStream::initialize ( const char *  path,
const char *  mode 
)

virtual bool LTIOFileStream::isEOF (  )  [virtual]

Returns true after the first read operation that attempts to read past the end of the stream. It returns false if the current position is not end of stream.

Return values:
true end of stream
false otherwise

Implements LTIOStreamInf.

virtual bool LTIOFileStream::isOpen (  )  [virtual]

Return values:
true The stream is open
false otherwise

Implements LTIOStreamInf.

virtual LT_STATUS LTIOFileStream::open (  )  [virtual]

Opening a stream puts it in a state that allows data access based on cached initialization parameters.

Return values:
LT_STS_IOStreamUninitialized The stream has not been initialized with enough information to open the stream
LT_STS_IOStreamInvalidState The stream is already open
LT_STS_Success On success.
LT_STS_Failure Failure.
other Implementations may return other codes

Implements LTIOStreamInf.

Examples:
UsingStreams.cpp.

virtual LT_STATUS LTIOFileStream::close (  )  [virtual]

Puts the stream in a state that does not allow data access. May free up resources, but only in such a way that doesn't inhibit successful future calls to open()

Return values:
LT_STS_Success On success, or if the stream is already closed.
LT_STS_Failure Otherwise.

Implements LTIOStreamInf.

Examples:
UsingStreams.cpp.

virtual lt_uint32 LTIOFileStream::read ( lt_uint8 pDest,
lt_uint32  numBytes 
) [virtual]

Parameters:
pDest buffer in which to store read data
numBytes number of bytes to read from stream
Return values:
numBytes The number of bytes actually read

Implements LTIOStreamInf.

Examples:
UsingStreams.cpp.

virtual lt_uint32 LTIOFileStream::write ( const lt_uint8 pSrc,
lt_uint32  numBytes 
) [virtual]

Parameters:
pSrc buffer from which to store data
numBytes number of bytes to write to stream
Return values:
numBytes number of bytes actually written

Implements LTIOStreamInf.

virtual LT_STATUS LTIOFileStream::seek ( lt_int64  offset,
LTIOSeekDir  origin 
) [virtual]

Parameters:
offset number of bytes from origin at which to the next read or write will take place
origin place in stream from which to seek
Return values:
LT_STS_IOStreamUnsupported The stream is not seekable
LT_STS_IOStreamInvalidArgs The offset and origin do not specify a valid location in the stream
LT_STS_Success On success
LT_STS_Failure Otherwise
other Implementations may return other codes

Implements LTIOStreamInf.

Examples:
UsingStreams.cpp.

virtual lt_int64 LTIOFileStream::tell (  )  [virtual]

Return values:
postion Number of bytes from the start of the data
-1 On error.
other Implementations may return other codes

Implements LTIOStreamInf.

Examples:
UsingStreams.cpp.

virtual LTIOStreamInf* LTIOFileStream::duplicate (  )  [virtual]

Create new stream of the same type with the same initialization parameters. The transmission of these parameters is the responsibility of the derived type. The new stream should initially return false for isOpen().

Return values:
NULL the stream could not be duplicated; valid LTIOStreamInf* otherwise.

Implements LTIOStreamInf.

virtual LT_STATUS LTIOFileStream::getLastError (  )  const [virtual]

read(), write(), tell(), and duplicate() do not explicitly return status codes in the event of an error. When an error has occurred, this function returns the appropriate status code. Note calling this function after a successful I/O operation will return an undefined value.

Return values:
status the error code

Implements LTIOStreamInf.

virtual const char* LTIOFileStream::getID (  )  const [virtual]

This function returns a UTF-8, null-terminated string which is a URI describing the origin of the stream object -- for example, "file://foo.txt" or "lt_memstream:". This string is only intended for diagnostic purposes, i.e. it may not be valid to pass it to the ctor in an attempt to reopen the stream.

Return values:
uri the uri string

Implements LTIOStreamInf.

int LTIOFileStream::stdio_ferror (  ) 

void LTIOFileStream::stdio_clearerr (  ) 

int LTIOFileStream::stdio_setvbuf ( lt_uint8 buf,
lt_uint32  mode,
lt_uint32  size 
)

Parameters:
buf buffer to use; if NULL then one is allocated
mode one of the following: _IONBF (unbuffered) _IOLBF (line buffered) _IOFBF (fully buffered)
size size of buffer


Member Data Documentation

FILE* LTIOFileStream::m_file [protected]

Definition at line 111 of file lt_ioFileStream.h.

enum { ... } LTIOFileStream::m_state [protected]

Definition at line 121 of file lt_ioFileStream.h.

char* LTIOFileStream::m_mode [protected]

Definition at line 122 of file lt_ioFileStream.h.

char* LTIOFileStream::m_uri [protected]

Definition at line 123 of file lt_ioFileStream.h.


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

LizardTech