Crypto++ 7.0 Free C++ class library of cryptographic schemes

Public Member Functions | List of all members
Filter Class Reference

Implementation of BufferedTransformation's attachment interface. More...

Inheritance diagram for Filter:

## Public Member Functions
size_t | TransferTo2 (BufferedTransformation &target, lword &transferBytes, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true)
| Transfer bytes from this object to another BufferedTransformation. More...
size_t | CopyRangeTo2 (BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const
| Copy bytes from this object to another BufferedTransformation. More...
void | Initialize (const NameValuePairs &parameters=g_nullNameValuePairs, int propagation=-1)
| Initialize or reinitialize this object, with signal propagation. More...
bool | Flush (bool hardFlush, int propagation=-1, bool blocking=true)
| Flush buffered input and/or output, with signal propagation. More...
bool | MessageSeriesEnd (int propagation=-1, bool blocking=true)
| Marks the end of a series of messages, with signal propagation. More...
ATTACHMENT
| Filter (BufferedTransformation *attachment=NULL)
| Construct a Filter. More...
bool | Attachable ()
| Determine if attachable. More...
BufferedTransformation * | AttachedTransformation ()
| Retrieve attached transformation. More...
const BufferedTransformation * | AttachedTransformation () const
| Retrieve attached transformation. More...
void | Detach (BufferedTransformation *newAttachment=NULL)
| Replace an attached transformation. More...
Public Member Functions inherited from BufferedTransformation
| BufferedTransformation ()
| Construct a BufferedTransformation.
BufferedTransformation & | Ref ()
| Provides a reference to this object. More...
size_t | Put (byte inByte, bool blocking=true)
| Input a byte for processing. More...
size_t | Put (const byte *inString, size_t length, bool blocking=true)
| Input a byte buffer for processing. More...
size_t | PutWord16 (word16 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
| Input a 16-bit word for processing. More...
size_t | PutWord32 (word32 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
| Input a 32-bit word for processing. More...
virtual byte * | CreatePutSpace (size_t &size)
| Request space which can be written into by the caller. More...
virtual bool | CanModifyInput () const
| Determines whether input can be modified by the callee. More...
size_t | PutModifiable (byte *inString, size_t length, bool blocking=true)
| Input multiple bytes that may be modified by callee. More...
bool | MessageEnd (int propagation=-1, bool blocking=true)
| Signals the end of messages to the object. More...
size_t | PutMessageEnd (const byte *inString, size_t length, int propagation=-1, bool blocking=true)
| Input multiple bytes for processing and signal the end of a message. More...
virtual size_t | Put2 (const byte *inString, size_t length, int messageEnd, bool blocking)=0
| Input multiple bytes for processing. More...
virtual size_t | PutModifiable2 (byte *inString, size_t length, int messageEnd, bool blocking)
| Input multiple bytes that may be modified by callee. More...
unsigned int | GetMaxWaitObjectCount () const
| Retrieves the maximum number of waitable objects.
void | GetWaitObjects (WaitObjectContainer &container, CallStack const &callStack)
| Retrieves waitable objects. More...
virtual void | IsolatedInitialize (const NameValuePairs &parameters)
| Initialize or reinitialize this object, without signal propagation. More...
virtual bool | IsolatedFlush (bool hardFlush, bool blocking)=0
| Flushes data buffered by this object, without signal propagation. More...
virtual bool | IsolatedMessageSeriesEnd (bool blocking)
| Marks the end of a series of messages, without signal propagation. More...
virtual void | SetAutoSignalPropagation (int propagation)
| Set propagation of automatically generated and transferred signals. More...
virtual int | GetAutoSignalPropagation () const
| Retrieve automatic signal propagation value. More...
virtual lword | MaxRetrievable () const
| Provides the number of bytes ready for retrieval. More...
virtual bool | AnyRetrievable () const
| Determines whether bytes are ready for retrieval. More...
virtual size_t | Get (byte &outByte)
| Retrieve a 8-bit byte. More...
virtual size_t | Get (byte *outString, size_t getMax)
| Retrieve a block of bytes. More...
virtual size_t | Peek (byte &outByte) const
| Peek a 8-bit byte. More...
virtual size_t | Peek (byte *outString, size_t peekMax) const
| Peek a block of bytes. More...
size_t | GetWord16 (word16 &value, ByteOrder order=BIG_ENDIAN_ORDER)
| Retrieve a 16-bit word. More...
size_t | GetWord32 (word32 &value, ByteOrder order=BIG_ENDIAN_ORDER)
| Retrieve a 32-bit word. More...
size_t | PeekWord16 (word16 &value, ByteOrder order=BIG_ENDIAN_ORDER) const
| Peek a 16-bit word. More...
size_t | PeekWord32 (word32 &value, ByteOrder order=BIG_ENDIAN_ORDER) const
| Peek a 32-bit word. More...
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 More...
virtual lword | Skip (lword skipMax=LWORD_MAX)
| Discard skipMax bytes from the output buffer. More...
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 More...
lword | CopyRangeTo (BufferedTransformation &target, lword position, lword copyMax=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL) const
| Copy bytes from this object using an index to another BufferedTransformation. More...
virtual lword | TotalBytesRetrievable () const
| Provides the number of bytes ready for retrieval. More...
virtual unsigned int | NumberOfMessages () const
| Provides the number of meesages processed by this object. More...
virtual bool | AnyMessages () const
| Determines if any messages are available for retrieval. More...
virtual bool | GetNextMessage ()
| Start retrieving the next message. More...
virtual unsigned int | SkipMessages (unsigned int count=UINT_MAX)
| Skip a number of meessages. More...
unsigned int | TransferMessagesTo (BufferedTransformation &target, unsigned int count=UINT_MAX, const std::string &channel=DEFAULT_CHANNEL)
| Transfer messages from this object to another BufferedTransformation. More...
unsigned int | CopyMessagesTo (BufferedTransformation &target, unsigned int count=UINT_MAX, const std::string &channel=DEFAULT_CHANNEL) const
| Copy messages from this object to another BufferedTransformation. More...
virtual void | SkipAll ()
| Skip all messages in the series.
void | TransferAllTo (BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL)
| Transfer all bytes from this object to another BufferedTransformation. More...
void | CopyAllTo (BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL) const
| Copy messages from this object to another BufferedTransformation. More...
virtual bool | GetNextMessageSeries ()
| Retrieve the next message in a series. More...
virtual unsigned int | NumberOfMessagesInThisSeries () const
| Provides the number of messages in a series. More...
virtual unsigned int | NumberOfMessageSeries () const
| Provides the number of messages in a series. More...
size_t | TransferMessagesTo2 (BufferedTransformation &target, unsigned int &messageCount, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true)
| Transfer messages from this object to another BufferedTransformation. More...
size_t | TransferAllTo2 (BufferedTransformation &target, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true)
| Transfer all bytes from this object to another BufferedTransformation. More...
size_t | ChannelPut (const std::string &channel, byte inByte, bool blocking=true)
| Input a byte for processing on a channel. More...
size_t | ChannelPut (const std::string &channel, const byte *inString, size_t length, bool blocking=true)
| Input a byte buffer for processing on a channel. More...
size_t | ChannelPutModifiable (const std::string &channel, byte *inString, size_t length, bool blocking=true)
| Input multiple bytes that may be modified by callee on a channel. More...
size_t | ChannelPutWord16 (const std::string &channel, word16 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
| Input a 16-bit word for processing on a channel. More...
size_t | ChannelPutWord32 (const std::string &channel, word32 value, ByteOrder order=BIG_ENDIAN_ORDER, bool blocking=true)
| Input a 32-bit word for processing on a channel. More...
bool | ChannelMessageEnd (const std::string &channel, int propagation=-1, bool blocking=true)
| Signal the end of a message. More...
size_t | ChannelPutMessageEnd (const std::string &channel, const byte *inString, size_t length, int propagation=-1, bool blocking=true)
| Input multiple bytes for processing and signal the end of a message. More...
virtual byte * | ChannelCreatePutSpace (const std::string &channel, size_t &size)
| Request space which can be written into by the caller. More...
virtual size_t | ChannelPut2 (const std::string &channel, const byte *inString, size_t length, int messageEnd, bool blocking)
| Input multiple bytes for processing on a channel. More...
virtual size_t | ChannelPutModifiable2 (const std::string &channel, byte *inString, size_t length, int messageEnd, bool blocking)
| Input multiple bytes that may be modified by callee on a channel. More...
virtual bool | ChannelFlush (const std::string &channel, bool hardFlush, int propagation=-1, bool blocking=true)
| Flush buffered input and/or output on a channel. More...
virtual bool | ChannelMessageSeriesEnd (const std::string &channel, int propagation=-1, bool blocking=true)
| Marks the end of a series of messages on a channel. More...
virtual void | SetRetrievalChannel (const std::string &channel)
| Sets the default retrieval channel. More...
virtual void | Attach (BufferedTransformation *newAttachment)
| Add newAttachment to the end of attachment chain. More...
Public Member Functions inherited from Algorithm
| Algorithm (bool checkSelfTestStatus=true)
| Interface for all crypto algorithms. More...
virtual std::string | AlgorithmName () const
| Provides the name of this algorithm. More...
virtual std::string | AlgorithmProvider () const
| Retrieve the provider of this algorithm. More...
Public Member Functions inherited from Clonable
virtual Clonable * | Clone () const
| Copies this object. More...
Public Member Functions inherited from Waitable
bool | Wait (unsigned long milliseconds, CallStack const &callStack)
| Wait on this object. More...

## Detailed Description

Implementation of BufferedTransformation's attachment interface.

Filter is a cornerstone of the Pipeline trinitiy. Data flows from Sources, through Filters, and then terminates in Sinks. The difference between a Source and Filter is a Source pumps data, while a Filter does not. The difference between a Filter and a Sink is a Filter allows an attached transformation, while a Sink does not.

See the discussion of BufferedTransformation in cryptlib.h for more details.

Definition at line 35 of file filters.h.

## Constructor & Destructor Documentation

## ◆ Filter()

Filter::Filter | ( | BufferedTransformation * | attachment = `NULL` | ) |

Construct a Filter.

Parameters

  attachment | an optional attached transformation

attachment can be `NULL`.

Definition at line 26 of file filters.cpp.

## Member Function Documentation

## ◆ Attachable()

bool Filter::Attachable | ( |  | ) |
| inline virtual

Determine if attachable.

Returns
  `true` if the object allows attached transformations, `false` otherwise.

Note
  Source and Filter offer attached transformations; while Sink does not.

Reimplemented from BufferedTransformation.

Definition at line 51 of file filters.h.

## ◆ AttachedTransformation() [1/2]

BufferedTransformation * Filter::AttachedTransformation | ( |  | ) |
| virtual

Retrieve attached transformation.

Returns
  pointer to a BufferedTransformation if there is an attached transformation, `NULL` otherwise.

Reimplemented from BufferedTransformation.

Definition at line 36 of file filters.cpp.

## ◆ AttachedTransformation() [2/2]

const BufferedTransformation * Filter::AttachedTransformation | ( |  | ) | const
| virtual

Retrieve attached transformation.

Returns
  pointer to a BufferedTransformation if there is an attached transformation, `NULL` otherwise.

Reimplemented from BufferedTransformation.

Definition at line 43 of file filters.cpp.

## ◆ Detach()

void Filter::Detach | ( | BufferedTransformation * | newAttachment = `NULL` | ) |
| virtual

Replace an attached transformation.

Parameters

  newAttachment | an optional attached transformation

newAttachment can be a single filter, a chain of filters or `NULL`. Pass `NULL` to remove an existing BufferedTransformation or chain of filters

Reimplemented from BufferedTransformation.

Definition at line 50 of file filters.cpp.

## ◆ TransferTo2()

size_t Filter::TransferTo2 | ( | BufferedTransformation & | target,
|  | lword & | byteCount,
|  | const std::string & | channel = `DEFAULT_CHANNEL`,
|  | bool | blocking = `true`
| ) |  |
| virtual

Transfer bytes from this object to another BufferedTransformation.

Parameters

  target | the destination BufferedTransformation
  byteCount | the number of bytes to transfer
  channel | the channel on which the transfer should occur
  blocking | specifies whether the object should block when processing input

Returns
  the number of bytes that remain in the transfer block (i.e., bytes not transferred)

TransferTo() removes bytes from this object and moves them to the destination. Transfer begins at the index position in the current stream, and not from an absolute position in the stream.

byteCount is an IN and OUT parameter. When the call is made, byteCount is the requested size of the transfer. When the call returns, byteCount is the number of bytes that were transferred.

Implements BufferedTransformation.

Definition at line 66 of file filters.cpp.

## ◆ CopyRangeTo2()

size_t Filter::CopyRangeTo2 | ( | BufferedTransformation & | target,
|  | lword & | begin,
|  | lword | end = `LWORD_MAX`,
|  | const std::string & | channel = `DEFAULT_CHANNEL`,
|  | bool | blocking = `true`
| ) |  | const
| virtual

Copy bytes from this object to another BufferedTransformation.

Parameters

  target | the destination BufferedTransformation
  begin | the 0-based index of the first byte to copy in the stream
  end | the 0-based index of the last byte to copy in the stream
  channel | the channel on which the transfer should occur
  blocking | specifies whether the object should block when processing input

Returns
  the number of bytes that remain in the copy block (i.e., bytes not copied)

CopyRangeTo2 copies bytes from this object to the destination. The bytes are not removed from this object. Copying begins at the index position in the current stream, and not from an absolute position in the stream.

begin is an IN and OUT parameter. When the call is made, begin is the starting position of the copy. When the call returns, begin is the position of the first byte that was not copied (which may be different than end). begin can be used for subsequent calls to CopyRangeTo2().

Implements BufferedTransformation.

Definition at line 61 of file filters.cpp.

## ◆ Initialize()

void Filter::Initialize | ( | const NameValuePairs & | parameters = `g_nullNameValuePairs`,
|  | int | propagation = `-1`
| ) |  |
| virtual

Initialize or reinitialize this object, with signal propagation.

Parameters

  parameters | a set of NameValuePairs to initialize or reinitialize this object
  propagation | the number of attached transformations the Initialize() signal should be passed

Initialize() is used to initialize or reinitialize an object using a variable number of arbitrarily typed arguments. The function avoids the need for multiple constructors providing all possible combintations of configurable parameters.

propagation count includes this object. Setting propagation to `1` means this object only. Setting propagation to `-1` means unlimited propagation.

Reimplemented from BufferedTransformation.

Definition at line 71 of file filters.cpp.

## ◆ Flush()

bool Filter::Flush | ( | bool | hardFlush,
|  | int | propagation = `-1`,
|  | bool | blocking = `true`
| ) |  |
| virtual

Flush buffered input and/or output, with signal propagation.

Parameters

  hardFlush | is used to indicate whether all data should be flushed
  propagation | the number of attached transformations the Flush() signal should be passed
  blocking | specifies whether the object should block when processing input

propagation count includes this object. Setting propagation to `1` means this object only. Setting propagation to `-1` means unlimited propagation.

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, like 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 from BufferedTransformation.

Reimplemented in Multichannel< Filter >, CustomFlushPropagation< Filter >, InformationDispersal, and SecretSharing.

Definition at line 78 of file filters.cpp.

## ◆ MessageSeriesEnd()

bool Filter::MessageSeriesEnd | ( | int | propagation = `-1`,
|  | bool | blocking = `true`
| ) |  |
| virtual

Marks the end of a series of messages, with signal propagation.

Parameters

  propagation | the number of attached transformations the MessageSeriesEnd() signal should be passed
  blocking | specifies whether the object should block when processing input

Each object that receives the signal will perform its processing, decrement propagation, and then pass the signal on to attached transformations if the value is not 0.

propagation count includes this object. Setting propagation to `1` means this object only. Setting propagation to `-1` means unlimited propagation.

Note
  There should be a MessageEnd() immediately before MessageSeriesEnd().

Reimplemented from BufferedTransformation.

Reimplemented in Multichannel< Filter >.

Definition at line 95 of file filters.cpp.

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

- filters.h
- filters.cpp