LTIODynamicMemStream Class Reference

holds a memory buffer of variable size More...

#include <lt_ioDynamicMemStream.h>

Inheritance diagram for LTIODynamicMemStream:
LTIOStreamInf

List of all members.

Public Types

Memory Allocation and Deallocation Functions



typedef void *(* Allocator )(size_t)
typedef void(* Deallocator )(void *)
typedef void *(* Reallocator )(void *, size_t)

Public Member Functions

 LTIODynamicMemStream ()
virtual ~LTIODynamicMemStream ()
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.
virtual char * readString (int delimiter)
 read a delimiter-terminated string
Initialization functions



virtual LT_STATUS initialize (lt_uint32 size=4096, float growthRate=2)
 Initializes the stream.
virtual LT_STATUS initialize (lt_uint32 size, Allocator allo, Deallocator deallo, Reallocator reallo=NULL, float growthRate=2)
 Initializes the stream, with custom memory management.
Memory Management



Allocator getAllocator () const
 Returns the allocator function pointer.
Deallocator getDeallocator () const
 Returns the deallocator function pointer.
Reallocator getReallocator () const
 Returns the reallocator function pointer.
const lt_uint8getData () const
 Get the underlying buffer.
LT_STATUS detachAndClose (lt_uint8 *&data)
 Detach the underlying buffer from the stream, and closes the stream.
lt_uint64 size () const
 Returns the number of bytes which are in the stream.

Protected Member Functions

bool grow (lt_uint32 numBytes)
 extend size of data buffer if required
void * defaultRealloc (void *, size_t)

Protected Attributes

lt_uint8m_data
 pointer to buffer
lt_uint32 m_initialSize
 initial size of buffer
lt_uint32 m_bufferSize
 size of buffer as allocated
lt_uint32 m_userSize
 size of buffer as accessible by user
lt_uint32 m_cur
 current position
bool m_isOpen
 openness
Allocator m_alloc
 allocator function
Deallocator m_dealloc
 deallocator
Reallocator m_realloc
 reallocator
LT_STATUS m_lastError
bool m_isEOF
float m_growthRate
 the factor of growth of the memory [1-2):

Detailed Description

Unlike LTIOMemStream, which uses a fixed-size buffer, this class will grow its buffer as you write past the end of it. It is most suitable for use as an internal "temp stream". The stream is initially empty.

The stream cannot hold more than 2^32 bytes of data.

Definition at line 33 of file lt_ioDynamicMemStream.h.


Member Typedef Documentation

typedef void*(* LTIODynamicMemStream::Allocator)(size_t)

Definition at line 43 of file lt_ioDynamicMemStream.h.

typedef void(* LTIODynamicMemStream::Deallocator)(void *)

Definition at line 44 of file lt_ioDynamicMemStream.h.

typedef void*(* LTIODynamicMemStream::Reallocator)(void *, size_t)

Definition at line 45 of file lt_ioDynamicMemStream.h.


Constructor & Destructor Documentation

LTIODynamicMemStream::LTIODynamicMemStream (  ) 
virtual LTIODynamicMemStream::~LTIODynamicMemStream (  )  [virtual]

Member Function Documentation

virtual LT_STATUS LTIODynamicMemStream::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.

void* LTIODynamicMemStream::defaultRealloc ( void *  ,
size_t   
) [protected]
LT_STATUS LTIODynamicMemStream::detachAndClose ( lt_uint8 *&  data  ) 

The caller is responsible for deallocating the buffer. (Note that you must use the Deallocator method, not delete[].)

Parameters:
data receives pointer to underlying buffer
Returns:
LT_STS_Success upon success
virtual LTIOStreamInf* LTIODynamicMemStream::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.

Allocator LTIODynamicMemStream::getAllocator (  )  const [inline]

Definition at line 101 of file lt_ioDynamicMemStream.h.

const lt_uint8* LTIODynamicMemStream::getData (  )  const [inline]

The pointer is guaranteed to be good until the next call to write(), or close()

Returns:
pointer to underlying buffer

Definition at line 121 of file lt_ioDynamicMemStream.h.

Deallocator LTIODynamicMemStream::getDeallocator (  )  const [inline]

Definition at line 106 of file lt_ioDynamicMemStream.h.

virtual const char* LTIODynamicMemStream::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.

virtual LT_STATUS LTIODynamicMemStream::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.

Reallocator LTIODynamicMemStream::getReallocator (  )  const [inline]

Definition at line 111 of file lt_ioDynamicMemStream.h.

bool LTIODynamicMemStream::grow ( lt_uint32  numBytes  )  [protected]
virtual LT_STATUS LTIODynamicMemStream::initialize ( lt_uint32  size,
Allocator  allo,
Deallocator  deallo,
Reallocator  reallo = NULL,
float  growthRate = 2 
) [virtual]

The allocator function should return NULL in the event of failure, as opposed to throwing an exception -- that is, be like malloc() and not like new.

Parameters:
size initial size of buffer in bytes
allo user-defined memory allocator
deallo user-defined memory deallocator
reallo user-defined memory reallocator
growthRate factor of growth Valid Values: [1-2)
virtual LT_STATUS LTIODynamicMemStream::initialize ( lt_uint32  size = 4096,
float  growthRate = 2 
) [virtual]
Parameters:
size initial size of buffer in bytes
growthRate factor of growth Valid Values: [1-2)
virtual bool LTIODynamicMemStream::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 LTIODynamicMemStream::isOpen (  )  [virtual]
Return values:
true The stream is open
false otherwise

Implements LTIOStreamInf.

virtual LT_STATUS LTIODynamicMemStream::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.

virtual lt_uint32 LTIODynamicMemStream::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.

virtual char* LTIODynamicMemStream::readString ( int  delimiter  )  [virtual]
Return values:
returns NULL on failure

Reimplemented from LTIOStreamInf.

virtual LT_STATUS LTIODynamicMemStream::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.

lt_uint64 LTIODynamicMemStream::size (  )  const [inline]

This may be smaller than the amount actually allocated.

Returns:
size (in bytes) of stream

Definition at line 143 of file lt_ioDynamicMemStream.h.

virtual lt_int64 LTIODynamicMemStream::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.

virtual lt_uint32 LTIODynamicMemStream::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.


Member Data Documentation

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

LizardTech