Crypto++
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BufferedTransformation Class Referenceabstract

interface for buffered transformations More...

#include <cryptlib.h>

Inheritance diagram for BufferedTransformation:
Algorithm Waitable Clonable AutoSignaling< BufferedTransformation > Bufferless< BufferedTransformation > Filter InputRejecting< BufferedTransformation > Sink MessageQueue ByteQueue AutoSignaling< Filter > Bufferless< Filter > CustomFlushPropagation< Filter > EncodedObjectFilter FilterWithBufferedInput FilterWithInputQueue InputRejecting< Filter > LowFirstBitWriter Unflushable< Filter > AutoSignaling< InputRejecting< BufferedTransformation > > ByteQueue::Walker Bufferless< Sink > CustomFlushPropagation< Sink > FileSink NonblockingSink

Classes

struct  BlockingInputOnly
 thrown by objects that have not implemented nonblocking input processing More...
 
struct  InvalidChannelName
 
struct  NoChannelSupport
 

Public Member Functions

BufferedTransformationRef ()
 return a reference to this object, useful for passing a temporary object to a function that takes a non-const reference
 
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, CallStack const &callStack)
 wait on this object More...
 

Static Public Attributes

static const std::string & NULL_CHANNEL
 

Static Protected Member Functions

static int DecrementPropagation (int propagation)
 

INPUT

size_t Put (byte inByte, bool blocking=true)
 input a byte for processing
 
size_t Put (const byte *inString, size_t length, bool blocking=true)
 input multiple bytes
 
size_t PutWord16 (word16 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
 input a 16-bit word
 
size_t PutWord32 (word32 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
 input a 32-bit word
 
virtual byte * CreatePutSpace (size_t &size)
 request space which can be written into by the caller, and then used as input to Put() More...
 
virtual bool CanModifyInput () const
 
size_t PutModifiable (byte *inString, size_t length, bool blocking=true)
 input multiple bytes that may be modified by callee
 
bool MessageEnd (int propagation=-1, bool blocking=true)
 
size_t PutMessageEnd (const byte *inString, size_t length, int propagation=-1, bool blocking=true)
 
virtual size_t Put2 (const byte *inString, size_t length, int messageEnd, bool blocking)=0
 input multiple bytes for blocking or non-blocking processing More...
 
virtual size_t PutModifiable2 (byte *inString, size_t length, int messageEnd, bool blocking)
 input multiple bytes that may be modified by callee for blocking or non-blocking processing More...
 

WAITING

unsigned int GetMaxWaitObjectCount () const
 maximum number of wait objects that this object can return
 
void GetWaitObjects (WaitObjectContainer &container, CallStack const &callStack)
 put wait objects into container More...
 

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 More...
 
virtual bool MessageSeriesEnd (int propagation=-1, bool blocking=true)
 mark end of a series of messages More...
 
virtual void SetAutoSignalPropagation (int propagation)
 set propagation of automatically generated and transferred signals More...
 
virtual int GetAutoSignalPropagation () const
 

RETRIEVAL OF ONE MESSAGE

virtual lword MaxRetrievable () const
 returns number of bytes that is currently ready for retrieval More...
 
virtual bool AnyRetrievable () const
 returns whether any bytes are currently ready for retrieval
 
virtual size_t Get (byte &outByte)
 try to retrieve a single byte
 
virtual size_t Get (byte *outString, size_t getMax)
 try to retrieve multiple bytes
 
virtual size_t Peek (byte &outByte) const
 peek at the next byte without removing it from the output buffer
 
virtual size_t Peek (byte *outString, size_t peekMax) const
 peek at multiple bytes without removing them from the output buffer
 
size_t GetWord16 (word16 &value, ByteOrder order=BIG_ENDIAN_ORDER)
 try to retrieve a 16-bit word
 
size_t GetWord32 (word32 &value, ByteOrder order=BIG_ENDIAN_ORDER)
 try to retrieve a 32-bit word
 
size_t PeekWord16 (word16 &value, ByteOrder order=BIG_ENDIAN_ORDER) const
 try to peek at a 16-bit word
 
size_t PeekWord32 (word32 &value, ByteOrder order=BIG_ENDIAN_ORDER) const
 try to peek at a 32-bit word
 
lword TransferTo (BufferedTransformation &target, lword transferMax=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL)
 move transferMax bytes of the buffered output to target as input
 
virtual lword Skip (lword skipMax=LWORD_MAX)
 discard skipMax bytes from the output buffer
 
lword CopyTo (BufferedTransformation &target, lword copyMax=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL) const
 copy copyMax bytes of the buffered output to target as input
 
lword CopyRangeTo (BufferedTransformation &target, lword position, lword copyMax=LWORD_MAX, const std::string &channel=DEFAULT_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 lword 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 More...
 
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=DEFAULT_CHANNEL)
 
unsigned int CopyMessagesTo (BufferedTransformation &target, unsigned int count=UINT_MAX, const std::string &channel=DEFAULT_CHANNEL) const
 
virtual void SkipAll ()
 
void TransferAllTo (BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL)
 
void CopyAllTo (BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL) const
 
virtual bool GetNextMessageSeries ()
 
virtual unsigned int NumberOfMessagesInThisSeries () const
 
virtual unsigned int NumberOfMessageSeries () const
 

NON-BLOCKING TRANSFER OF OUTPUT

virtual size_t TransferTo2 (BufferedTransformation &target, lword &byteCount, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true)=0
 upon return, byteCount contains number of bytes that have finished being transfered, and returns the number of bytes left in the current transfer block
 
virtual size_t CopyRangeTo2 (BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const =0
 upon return, begin contains the start position of data yet to be finished copying, and returns the number of bytes left in the current transfer block
 
size_t TransferMessagesTo2 (BufferedTransformation &target, unsigned int &messageCount, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true)
 upon return, messageCount contains number of messages that have finished being transfered, and returns the number of bytes left in the current transfer block
 
size_t TransferAllTo2 (BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true)
 returns the number of bytes left in the current transfer block
 

CHANNELS

size_t ChannelPut (const std::string &channel, byte inByte, bool blocking=true)
 
size_t ChannelPut (const std::string &channel, const byte *inString, size_t length, bool blocking=true)
 
size_t ChannelPutModifiable (const std::string &channel, byte *inString, size_t length, bool blocking=true)
 
size_t ChannelPutWord16 (const std::string &channel, word16 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
 
size_t 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)
 
size_t ChannelPutMessageEnd (const std::string &channel, const byte *inString, size_t length, int propagation=-1, bool blocking=true)
 
virtual byte * ChannelCreatePutSpace (const std::string &channel, size_t &size)
 
virtual size_t ChannelPut2 (const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking)
 
virtual size_t ChannelPutModifiable2 (const std::string &channel, byte *begin, size_t length, int messageEnd, bool blocking)
 
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 More...
 
virtual BufferedTransformationAttachedTransformation ()
 returns the object immediately attached to this object or NULL for no attachment
 
virtual const
BufferedTransformation
AttachedTransformation () 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
 

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 770 of file cryptlib.h.

Member Function Documentation

virtual byte* BufferedTransformation::CreatePutSpace ( size_t &  size)
inlinevirtual

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

Parameters
sizeis requested size (as a hint) for input, and size of the returned space for output
Note
The purpose of this method is to help avoid doing extra memory allocations.

Reimplemented in ArrayXorSink, ArraySink, OutputProxy, Redirector, HashFilter, MeterFilter, and ByteQueue.

Definition at line 798 of file cryptlib.h.

Referenced by ArrayXorSink::CreatePutSpace().

virtual size_t BufferedTransformation::Put2 ( const byte *  inString,
size_t  length,
int  messageEnd,
bool  blocking 
)
pure virtual

input multiple bytes for blocking or non-blocking processing

Parameters
messageEndmeans how many filters to signal MessageEnd to, including this one

Implemented in ArrayXorSink, ArraySink, RandomNumberSink, StringSinkTemplate< T >, OutputProxy, Redirector, SignerFilter, HashFilter, FilterWithInputQueue, BitBucket, NetworkSink, FilterWithBufferedInput, PaddingRemover, InformationDispersal, MeterFilter, Inflator, FileSink, Grouper, Deflator, SecretSharing, MaurerRandomnessTest, BaseN_Decoder, ByteQueue, BaseN_Encoder, and MessageQueue.

virtual size_t BufferedTransformation::PutModifiable2 ( byte *  inString,
size_t  length,
int  messageEnd,
bool  blocking 
)
inlinevirtual

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

Parameters
messageEndmeans how many filters to signal MessageEnd to, including this one

Reimplemented in OutputProxy, FilterWithBufferedInput, and MeterFilter.

Definition at line 816 of file cryptlib.h.

void BufferedTransformation::GetWaitObjects ( WaitObjectContainer container,
CallStack const &  callStack 
)
virtual

put wait objects into container

Parameters
callStackis used for tracing no wait loops, example: something.GetWaitObjects(c, CallStack("my func after X", 0));
  • or in an outer GetWaitObjects() method that itself takes a callStack parameter: innerThing.GetWaitObjects(c, CallStack("MyClass::GetWaitObjects at X", &callStack));

Implements Waitable.

Reimplemented in Redirector, NetworkSink, and NetworkSource.

virtual bool BufferedTransformation::Flush ( bool  hardFlush,
int  propagation = -1,
bool  blocking = true 
)
virtual

flush buffered input and/or output

Parameters
hardFlushis 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 OutputProxy, Redirector, InformationDispersal, SecretSharing, and Filter.

virtual 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 OutputProxy, Redirector, and Filter.

virtual void BufferedTransformation::SetAutoSignalPropagation ( int  propagation)
inlinevirtual

set propagation of automatically generated and transferred signals

propagation == 0 means do not automaticly generate signals

Reimplemented in SourceTemplate< T >, SourceTemplate< FileStore >, SourceTemplate< RandomNumberStore >, and SourceTemplate< StringStore >.

Definition at line 856 of file cryptlib.h.

virtual lword 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().

Reimplemented in NullStore, RandomNumberStore, ByteQueue::Walker, FileStore, MessageQueue, and ByteQueue.

Referenced by RandomNumberStore::AnyRetrievable().

virtual bool BufferedTransformation::GetNextMessage ( )
virtual

start retrieving the next message

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

Reimplemented in Store, and MessageQueue.

virtual bool BufferedTransformation::Attachable ( )
inlinevirtual

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 1008 of file cryptlib.h.

bool Waitable::Wait ( unsigned long  milliseconds,
CallStack const &  callStack 
)
inherited

wait on this object

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


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