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BufferedTransformation Class Reference

#include <cryptlib.h>

Inheritance diagram for BufferedTransformation:

Algorithm Waitable Clonable Filter Sink FilterWithBufferedInput FilterWithInputQueue LowFirstBitWriter FileSink MaurerRandomnessTest NonblockingSink HashVerificationFilter ProxyFilter SignatureVerificationFilter StreamTransformationFilter Deflator NetworkSink DefaultDecryptor DefaultDecryptorWithMAC DefaultEncryptor DefaultEncryptorWithMAC SimpleProxyFilter Gzip ZlibCompressor SocketSink WindowsPipeSink List of all members.

Detailed Description

interface for buffered transformations

BufferedTransformation is a generalization of BlockTransformation, StreamTransformation, and HashTransformation.

A buffered transformation is an object that takes a stream of bytes as input (this may be done in stages), does some computation on them, and then places the result into an internal buffer for later retrieval. Any partial result already in the output buffer is not modified by further input.

If a method takes a "blocking" parameter, and you pass "false" for it, the method will return before all input has been processed if the input cannot be processed without waiting (for network buffers to become available, for example). In this case the method will return true or a non-zero integer value. When this happens you must continue to call the method with the same parameters until it returns false or zero, before calling any other method on it or attached BufferedTransformation. The integer return value in this case is approximately the number of bytes left to be processed, and can be used to implement a progress bar.

For functions that take a "propagation" parameter, propagation != 0 means pass on the signal to attached BufferedTransformation objects, with propagation decremented at each step until it reaches 0. -1 means unlimited propagation.

Definition at line 670 of file cryptlib.h.

INPUT

unsigned int Put (byte inByte, bool blocking=true)
 input a byte for processing

unsigned int Put (const byte *inString, unsigned int length, bool blocking=true)
 input multiple bytes

unsigned int PutWord16 (word16 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
 input a 16-bit word

unsigned int PutWord32 (word32 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
 input a 32-bit word

virtual byte * CreatePutSpace (unsigned int &size)
 request space which can be written into by the caller, and then used as input to Put()

virtual bool CanModifyInput () const
unsigned int PutModifiable (byte *inString, unsigned int length, bool blocking=true)
 input multiple bytes that may be modified by callee

bool MessageEnd (int propagation=-1, bool blocking=true)
unsigned int PutMessageEnd (const byte *inString, unsigned int length, int propagation=-1, bool blocking=true)
virtual unsigned int Put2 (const byte *inString, unsigned int length, int messageEnd, bool blocking)=0
 input multiple bytes for blocking or non-blocking processing

virtual unsigned int PutModifiable2 (byte *inString, unsigned int length, int messageEnd, bool blocking)
 input multiple bytes that may be modified by callee for blocking or non-blocking processing


WAITING

unsigned int GetMaxWaitObjectCount () const
 maximum number of wait objects that this object can return

void GetWaitObjects (WaitObjectContainer &container)
 put wait objects into container


SIGNALS

virtual void IsolatedInitialize (const NameValuePairs &parameters)
virtual bool IsolatedFlush (bool hardFlush, bool blocking)=0
virtual bool IsolatedMessageSeriesEnd (bool blocking)
virtual void Initialize (const NameValuePairs &parameters=g_nullNameValuePairs, int propagation=-1)
 initialize or reinitialize this object

virtual bool Flush (bool hardFlush, int propagation=-1, bool blocking=true)
 flush buffered input and/or output

virtual bool MessageSeriesEnd (int propagation=-1, bool blocking=true)
 mark end of a series of messages

virtual void SetAutoSignalPropagation (int propagation)
 set propagation of automatically generated and transfered signals

virtual int GetAutoSignalPropagation () const

RETRIEVAL OF ONE MESSAGE

virtual unsigned long MaxRetrievable () const
 returns number of bytes that is currently ready for retrieval

virtual bool AnyRetrievable () const
 returns whether any bytes are currently ready for retrieval

virtual unsigned int Get (byte &outByte)
 try to retrieve a single byte

virtual unsigned int Get (byte *outString, unsigned int getMax)
 try to retrieve multiple bytes

virtual unsigned int Peek (byte &outByte) const
 peek at the next byte without removing it from the output buffer

virtual unsigned int Peek (byte *outString, unsigned int peekMax) const
 peek at multiple bytes without removing them from the output buffer

unsigned int GetWord16 (word16 &value, ByteOrder order=BIG_ENDIAN_ORDER)
 try to retrieve a 16-bit word

unsigned int GetWord32 (word32 &value, ByteOrder order=BIG_ENDIAN_ORDER)
 try to retrieve a 32-bit word

unsigned int PeekWord16 (word16 &value, ByteOrder order=BIG_ENDIAN_ORDER)
 try to peek at a 16-bit word

unsigned int PeekWord32 (word32 &value, ByteOrder order=BIG_ENDIAN_ORDER)
 try to peek at a 32-bit word

unsigned long TransferTo (BufferedTransformation &target, unsigned long transferMax=ULONG_MAX, const std::string &channel=NULL_CHANNEL)
 move transferMax bytes of the buffered output to target as input

virtual unsigned long Skip (unsigned long skipMax=ULONG_MAX)
 discard skipMax bytes from the output buffer

unsigned long CopyTo (BufferedTransformation &target, unsigned long copyMax=ULONG_MAX, const std::string &channel=NULL_CHANNEL) const
 copy copyMax bytes of the buffered output to target as input

unsigned long CopyRangeTo (BufferedTransformation &target, unsigned long position, unsigned long copyMax=ULONG_MAX, const std::string &channel=NULL_CHANNEL) const
 copy copyMax bytes of the buffered output, starting at position (relative to current position), to target as input


RETRIEVAL OF MULTIPLE MESSAGES

virtual unsigned long TotalBytesRetrievable () const
virtual unsigned int NumberOfMessages () const
 number of times MessageEnd() has been received minus messages retrieved or skipped

virtual bool AnyMessages () const
 returns true if NumberOfMessages() > 0

virtual bool GetNextMessage ()
 start retrieving the next message

virtual unsigned int SkipMessages (unsigned int count=UINT_MAX)
 skip count number of messages

unsigned int TransferMessagesTo (BufferedTransformation &target, unsigned int count=UINT_MAX, const std::string &channel=NULL_CHANNEL)
unsigned int CopyMessagesTo (BufferedTransformation &target, unsigned int count=UINT_MAX, const std::string &channel=NULL_CHANNEL) const
virtual void SkipAll ()
void TransferAllTo (BufferedTransformation &target, const std::string &channel=NULL_CHANNEL)
void CopyAllTo (BufferedTransformation &target, const std::string &channel=NULL_CHANNEL) const
virtual bool GetNextMessageSeries ()
virtual unsigned int NumberOfMessagesInThisSeries () const
virtual unsigned int NumberOfMessageSeries () const

NON-BLOCKING TRANSFER OF OUTPUT

virtual unsigned int TransferTo2 (BufferedTransformation &target, unsigned long &byteCount, const std::string &channel=NULL_CHANNEL, bool blocking=true)=0
 

virtual unsigned int CopyRangeTo2 (BufferedTransformation &target, unsigned long &begin, unsigned long end=ULONG_MAX, const std::string &channel=NULL_CHANNEL, bool blocking=true) const =0
unsigned int TransferMessagesTo2 (BufferedTransformation &target, unsigned int &messageCount, const std::string &channel=NULL_CHANNEL, bool blocking=true)
unsigned int TransferAllTo2 (BufferedTransformation &target, const std::string &channel=NULL_CHANNEL, bool blocking=true)

CHANNELS

unsigned int ChannelPut (const std::string &channel, byte inByte, bool blocking=true)
unsigned int ChannelPut (const std::string &channel, const byte *inString, unsigned int length, bool blocking=true)
unsigned int ChannelPutModifiable (const std::string &channel, byte *inString, unsigned int length, bool blocking=true)
unsigned int ChannelPutWord16 (const std::string &channel, word16 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
unsigned int ChannelPutWord32 (const std::string &channel, word32 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
bool ChannelMessageEnd (const std::string &channel, int propagation=-1, bool blocking=true)
unsigned int ChannelPutMessageEnd (const std::string &channel, const byte *inString, unsigned int length, int propagation=-1, bool blocking=true)
virtual byte * ChannelCreatePutSpace (const std::string &channel, unsigned int &size)
virtual unsigned int ChannelPut2 (const std::string &channel, const byte *begin, unsigned int length, int messageEnd, bool blocking)
virtual unsigned int ChannelPutModifiable2 (const std::string &channel, byte *begin, unsigned int length, int messageEnd, bool blocking)
virtual void ChannelInitialize (const std::string &channel, const NameValuePairs &parameters=g_nullNameValuePairs, int propagation=-1)
virtual bool ChannelFlush (const std::string &channel, bool hardFlush, int propagation=-1, bool blocking=true)
virtual bool ChannelMessageSeriesEnd (const std::string &channel, int propagation=-1, bool blocking=true)
virtual void SetRetrievalChannel (const std::string &channel)

ATTACHMENT

virtual bool Attachable ()
 returns whether this object allows attachment

virtual BufferedTransformationAttachedTransformation ()
 returns the object immediately attached to this object or NULL for no attachment

virtual const BufferedTransformationAttachedTransformation () const
virtual void Detach (BufferedTransformation *newAttachment=0)
 delete the current attachment chain and replace it with newAttachment

virtual void Attach (BufferedTransformation *newAttachment)
 add newAttachment to the end of attachment chain


Public Member Functions

BufferedTransformationRef ()
 return a reference to this object

virtual std::string AlgorithmName () const
 returns name of this algorithm, not universally implemented yet

virtual ClonableClone () const
 this is not implemented by most classes yet

bool Wait (unsigned long milliseconds)
 wait on this object


Static Public Attributes

const std::string NULL_CHANNEL

Static Protected Member Functions

int DecrementPropagation (int propagation)


Member Function Documentation

BufferedTransformation& BufferedTransformation::Ref  )  [inline]
 

return a reference to this object

This function is useful for passing a temporary BufferedTransformation object to a function that takes a non-const reference.

Definition at line 681 of file cryptlib.h.

virtual byte* BufferedTransformation::CreatePutSpace unsigned int &  size  )  [inline, virtual]
 

request space which can be written into by the caller, and then used as input to Put()

Note:
The purpose of this method is to help avoid doing extra memory allocations.

Definition at line 700 of file cryptlib.h.

virtual unsigned int BufferedTransformation::Put2 const byte *  inString,
unsigned int  length,
int  messageEnd,
bool  blocking
[pure virtual]
 

input multiple bytes for blocking or non-blocking processing

Parameters:
messageEnd means how many filters to signal MessageEnd to, including this one

Implemented in FileSink, FilterWithBufferedInput, FilterWithInputQueue, NetworkSink, and Deflator.

virtual unsigned int BufferedTransformation::PutModifiable2 byte *  inString,
unsigned int  length,
int  messageEnd,
bool  blocking
[inline, virtual]
 

input multiple bytes that may be modified by callee for blocking or non-blocking processing

Parameters:
messageEnd means how many filters to signal MessageEnd to, including this one

Reimplemented in FilterWithBufferedInput.

Definition at line 718 of file cryptlib.h.

bool BufferedTransformation::Flush bool  hardFlush,
int  propagation = -1,
bool  blocking = true
[virtual]
 

flush buffered input and/or output

Parameters:
hardFlush is used to indicate whether all data should be flushed
Note:
Hard flushes must be used with care. It means try to process and output everything, even if there may not be enough data to complete the action. For example, hard flushing a HexDecoder would cause an error if you do it after inputing an odd number of hex encoded characters. For some types of filters, for example ZlibDecompressor, hard flushes can only be done at "synchronization points". These synchronization points are positions in the data stream that are created by hard flushes on the corresponding reverse filters, in this example ZlibCompressor. This is useful when zlib compressed data is moved across a network in packets and compression state is preserved across packets, as in the ssh2 protocol.

Reimplemented in Filter.

Definition at line 166 of file cryptlib.cpp.

References AttachedTransformation(), and Flush().

Referenced by Flush().

bool BufferedTransformation::MessageSeriesEnd int  propagation = -1,
bool  blocking = true
[virtual]
 

mark end of a series of messages

There should be a MessageEnd immediately before MessageSeriesEnd.

Reimplemented in Filter.

Definition at line 172 of file cryptlib.cpp.

References AttachedTransformation(), and MessageSeriesEnd().

Referenced by MessageSeriesEnd().

virtual void BufferedTransformation::SetAutoSignalPropagation int  propagation  )  [inline, virtual]
 

set propagation of automatically generated and transfered signals

propagation == 0 means do not automaticly generate signals

Definition at line 758 of file cryptlib.h.

unsigned long BufferedTransformation::MaxRetrievable  )  const [virtual]
 

returns number of bytes that is currently ready for retrieval

All retrieval functions return the actual number of bytes retrieved, which is the lesser of the request number and MaxRetrievable().

Definition at line 226 of file cryptlib.cpp.

References AttachedTransformation(), and CopyTo().

bool BufferedTransformation::GetNextMessage  )  [virtual]
 

start retrieving the next message

Returns false if no more messages exist or this message is not completely retrieved.

Definition at line 315 of file cryptlib.cpp.

References AnyMessages(), and AttachedTransformation().

virtual bool BufferedTransformation::Attachable  )  [inline, virtual]
 

returns whether this object allows attachment

Some BufferedTransformation objects (e.g. Filter objects) allow other BufferedTransformation objects to be attached. When this is done, the first object instead of buffering its output, sents that output to the attached object as input. The entire attachment chain is deleted when the anchor object is destructed.

Reimplemented in Filter.

Definition at line 906 of file cryptlib.h.

Referenced by Attach().

bool Waitable::Wait unsigned long  milliseconds  )  [inherited]
 

wait on this object

same as creating an empty container, calling GetWaitObjects(), and calling Wait() on the container

Definition at line 247 of file wait.cpp.

References Waitable::GetWaitObjects(), WaitObjectContainer::Wait(), and Waitable::Wait().

Referenced by NetworkSource::GeneralPump2(), NetworkSink::TimedFlush(), and Waitable::Wait().


The documentation for this class was generated from the following files:
Generated on Wed Jul 28 08:07:11 2004 for Crypto++ by doxygen 1.3.7