source: git/src-cryptopp/filters.h

// filters.h - written and placed in the public domain by Wei Dai

//! \file filters.h
//! \brief Implementation of BufferedTransformation's attachment interface.

#ifndef CRYPTOPP_FILTERS_H
#define CRYPTOPP_FILTERS_H

#include "cryptlib.h"

#if CRYPTOPP_MSC_VERSION
# pragma warning(push)
# pragma warning(disable: 4127 4189 4514)
#endif

#include "cryptlib.h"
#include "simple.h"
#include "secblock.h"
#include "misc.h"
#include "smartptr.h"
#include "queue.h"
#include "algparam.h"
#include "stdcpp.h"

NAMESPACE_BEGIN(CryptoPP)

//! \class Filter
//! \brief Implementation of BufferedTransformation's attachment interface
//! \details 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 \a 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.
//! \details See the discussion of BufferedTransformation in cryptlib.h for
//!   more details.
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Filter : public BufferedTransformation, public NotCopyable
{
public:
#ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
        virtual ~Filter() {}
#endif

        //!     \name ATTACHMENT
        //@{

        //! \brief Construct a Filter
        //! \param attachment an optional attached transformation
        //! \details attachment can be \p NULL.
        Filter(BufferedTransformation *attachment = NULL);

        //! \brief Determine if attachable
        //! \returns \p true if the object allows attached transformations, \p false otherwise.
        //! \note Source and Filter offer attached transformations; while Sink does not.
        bool Attachable() {return true;}

        //! \brief Retrieve attached transformation
        //! \returns pointer to a BufferedTransformation if there is an attached transformation, \p NULL otherwise.
        BufferedTransformation *AttachedTransformation();

        //! \brief Retrieve attached transformation
        //! \returns pointer to a BufferedTransformation if there is an attached transformation, \p NULL otherwise.
        const BufferedTransformation *AttachedTransformation() const;

        //! \brief Replace an attached transformation
        //! \param newAttachment an optional attached transformation
        //! \details newAttachment can be a single filter, a chain of filters or \p NULL.
        //!    Pass \p NULL to remove an existing BufferedTransformation or chain of filters
        void Detach(BufferedTransformation *newAttachment = NULL);

        //@}

        // See the documentation for BufferedTransformation in cryptlib.h
        size_t TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true);
        size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const;

        // See the documentation for BufferedTransformation in cryptlib.h
        void Initialize(const NameValuePairs &parameters=g_nullNameValuePairs, int propagation=-1);
        bool Flush(bool hardFlush, int propagation=-1, bool blocking=true);
        bool MessageSeriesEnd(int propagation=-1, bool blocking=true);

protected:
        virtual BufferedTransformation * NewDefaultAttachment() const;
        void Insert(Filter *nextFilter);        // insert filter after this one

        virtual bool ShouldPropagateMessageEnd() const {return true;}
        virtual bool ShouldPropagateMessageSeriesEnd() const {return true;}

        void PropagateInitialize(const NameValuePairs &parameters, int propagation);

        //! \brief Forward processed data on to attached transformation
        //! \param outputSite unknown, system crash between keyboard and chair...
        //! \param inString the byte buffer to process
        //! \param length the size of the string, in bytes
        //! \param messageEnd means how many filters to signal MessageEnd() to, including this one
        //! \param blocking specifies whether the object should block when processing input
        //! \param channel the channel to process the data
        //! \returns the number of bytes that remain in the block (i.e., bytes not processed)
        size_t Output(int outputSite, const byte *inString, size_t length, int messageEnd, bool blocking, const std::string &channel=DEFAULT_CHANNEL);

        //! \brief Output multiple bytes that may be modified by callee.
        //! \param outputSite unknown, system crash between keyboard and chair...
        //! \param inString the byte buffer to process
        //! \param length the size of the string, in bytes
        //! \param messageEnd means how many filters to signal MessageEnd() to, including this one
        //! \param blocking specifies whether the object should block when processing input
        //! \param channel the channel to process the data
        //! \returns the number of bytes that remain in the block (i.e., bytes not processed)
        size_t OutputModifiable(int outputSite, byte *inString, size_t length, int messageEnd, bool blocking, const std::string &channel=DEFAULT_CHANNEL);

        //! \brief Signals the end of messages to the object
        //! \param outputSite unknown, system crash between keyboard and chair...
        //! \param propagation the number of attached transformations the  MessageEnd() signal should be passed
        //! \param blocking specifies whether the object should block when processing input
        //! \param channel the channel to process the data
        //! \returns TODO
        //! \details propagation count includes this object. Setting  propagation to <tt>1</tt> means this
        //!   object only. Setting propagation to <tt>-1</tt> means unlimited propagation.
        bool OutputMessageEnd(int outputSite, int propagation, bool blocking, const std::string &channel=DEFAULT_CHANNEL);

        //! \brief Flush buffered input and/or output, with signal propagation
        //! \param outputSite unknown, system crash between keyboard and chair...
        //! \param hardFlush is used to indicate whether all data should be flushed
        //! \param propagation the number of attached transformations the  Flush() signal should be passed
        //! \param blocking specifies whether the object should block when processing input
        //! \param channel the channel to process the data
        //! \returns TODO
        //! \details propagation count includes this object. Setting  propagation to <tt>1</tt> means this
        //!   object only. Setting  propagation to <tt>-1</tt> 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.
        //! \note 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.
        bool OutputFlush(int outputSite, bool hardFlush, int propagation, bool blocking, const std::string &channel=DEFAULT_CHANNEL);

        //! \brief Marks the end of a series of messages, with signal propagation
        //! \param outputSite unknown, system crash between keyboard and chair...
        //! \param propagation the number of attached transformations the  MessageSeriesEnd() signal should be passed
        //! \param blocking specifies whether the object should block when processing input
        //! \param channel the channel to process the data
        //! \returns TODO
        //! \details 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.
        //! \details propagation count includes this object. Setting  propagation to <tt>1</tt> means this
        //!   object only. Setting  propagation to <tt>-1</tt> means unlimited propagation.
        //! \note There should be a MessageEnd() immediately before MessageSeriesEnd().
        bool OutputMessageSeriesEnd(int outputSite, int propagation, bool blocking, const std::string &channel=DEFAULT_CHANNEL);

private:
        member_ptr<BufferedTransformation> m_attachment;

protected:
        size_t m_inputPosition;
        int m_continueAt;
};

//! \class FilterPutSpaceHelper
//! \brief Create a working space in a BufferedTransformation
struct CRYPTOPP_DLL FilterPutSpaceHelper
{
        //! \brief Create a working space in a BufferedTransformation
        //! \param target BufferedTransformation for the working space
        //! \param channel channel for the working space
        //! \param minSize minimum size of the allocation, in bytes
        //! \param desiredSize preferred size of the allocation, in bytes
        //! \param bufferSize actual size of the allocation, in bytes
        //! \pre <tt>desiredSize >= minSize</tt> and <tt>bufferSize >= minSize</tt>.
        //! \details \p bufferSize is an IN and OUT parameter. If HelpCreatePutSpace() returns a non-NULL value, then
        //!    bufferSize is valid and provides the size of the working space created for the caller.
        //! \details Internally, HelpCreatePutSpace() calls \ref BufferedTransformation::ChannelCreatePutSpace
        //!   "ChannelCreatePutSpace()" using \p desiredSize. If the target returns \p desiredSize with a size less
        //!   than \p minSize (i.e., the request could not be fulfilled), then an internal SecByteBlock
        //!   called \p m_tempSpace is resized and used for the caller.
        byte *HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize, size_t desiredSize, size_t &bufferSize)
        {
                CRYPTOPP_ASSERT(desiredSize >= minSize && bufferSize >= minSize);
                if (m_tempSpace.size() < minSize)
                {
                        byte *result = target.ChannelCreatePutSpace(channel, desiredSize);
                        if (desiredSize >= minSize)
                        {
                                bufferSize = desiredSize;
                                return result;
                        }
                        m_tempSpace.New(bufferSize);
                }

                bufferSize = m_tempSpace.size();
                return m_tempSpace.begin();
        }

        //! \brief Create a working space in a BufferedTransformation
        //! \param target the BufferedTransformation for the working space
        //! \param channel channel for the working space
        //! \param minSize minimum size of the allocation, in bytes
        //! \details Internally, the overload calls HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize, size_t desiredSize, size_t &bufferSize) using \p minSize for missing arguments.
        byte *HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize)
                {return HelpCreatePutSpace(target, channel, minSize, minSize, minSize);}

        //! \brief Create a working space in a BufferedTransformation
        //! \param target the BufferedTransformation for the working space
        //! \param channel channel for the working space
        //! \param minSize minimum size of the allocation, in bytes
        //! \param bufferSize the actual size of the allocation, in bytes
        //! \details Internally, the overload calls HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize, size_t desiredSize, size_t &bufferSize) using \p minSize for missing arguments.
        byte *HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize, size_t bufferSize)
                {return HelpCreatePutSpace(target, channel, minSize, minSize, bufferSize);}

        //! \brief Temporay working space
        SecByteBlock m_tempSpace;
};

//! \class MeterFilter
//! \brief Measure how many bytes and messages pass through the filter
//! \details measure how many bytes and messages pass through the filter. The filter also serves as valve by
//!   maintaining a list of ranges to skip during processing.
class CRYPTOPP_DLL MeterFilter : public Bufferless<Filter>
{
public:
        //! \brief Construct a MeterFilter
        //! \param attachment an optional attached transformation
        //! \param transparent flag indicating if the filter should function transparently
        //! \details \p attachment can be \p NULL. The filter is transparent by default. If the filter is
        //!   transparent, then PutMaybeModifiable() does not process a request and always returns 0.
        MeterFilter(BufferedTransformation *attachment=NULL, bool transparent=true)
                : m_transparent(transparent), m_currentMessageBytes(0), m_totalBytes(0)
                , m_currentSeriesMessages(0), m_totalMessages(0), m_totalMessageSeries(0)
                , m_begin(NULL), m_length(0) {Detach(attachment); ResetMeter();}

        //! \brief Set or change the transparent mode of this object
        //! \param transparent the new transparent mode
        void SetTransparent(bool transparent) {m_transparent = transparent;}

        //! \brief Adds a range to skip during processing
        //! \param message the message to apply the range
        //! \param position the 0-based index in the current stream
        //! \param size the length of the range
        //! \param sortNow flag indicating whether the range should be sorted
        //! \details Internally, MeterFilter maitains a deque of ranges to skip. As messages are processed,
        //!   ranges of bytes are skipped according to the list of ranges.
        void AddRangeToSkip(unsigned int message, lword position, lword size, bool sortNow = true);

        //! \brief Resets the meter
        //! \details ResetMeter() reinitializes the meter by setting counters to 0 and removing previous
        //!   skip ranges.
        void ResetMeter();

        void IsolatedInitialize(const NameValuePairs &parameters)
                {CRYPTOPP_UNUSED(parameters); ResetMeter();}

        lword GetCurrentMessageBytes() const {return m_currentMessageBytes;}
        lword GetTotalBytes() const {return m_totalBytes;}
        unsigned int GetCurrentSeriesMessages() const {return m_currentSeriesMessages;}
        unsigned int GetTotalMessages() const {return m_totalMessages;}
        unsigned int GetTotalMessageSeries() const {return m_totalMessageSeries;}

        byte * CreatePutSpace(size_t &size)
                {return AttachedTransformation()->CreatePutSpace(size);}
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);
        size_t PutModifiable2(byte *inString, size_t length, int messageEnd, bool blocking);
        bool IsolatedMessageSeriesEnd(bool blocking);

private:
        size_t PutMaybeModifiable(byte *inString, size_t length, int messageEnd, bool blocking, bool modifiable);
        bool ShouldPropagateMessageEnd() const {return m_transparent;}
        bool ShouldPropagateMessageSeriesEnd() const {return m_transparent;}

        struct MessageRange
        {
                inline bool operator<(const MessageRange &b) const      // BCB2006 workaround: this has to be a member function
                        {return message < b.message || (message == b.message && position < b.position);}
                unsigned int message; lword position; lword size;
        };

        bool m_transparent;
        lword m_currentMessageBytes, m_totalBytes;
        unsigned int m_currentSeriesMessages, m_totalMessages, m_totalMessageSeries;
        std::deque<MessageRange> m_rangesToSkip;
        byte *m_begin;
        size_t m_length;
};

//! \class TransparentFilter
//! \brief A transparent MeterFilter
//! \sa MeterFilter, OpaqueFilter
class CRYPTOPP_DLL TransparentFilter : public MeterFilter
{
public:
        //! \brief Construct a TransparentFilter
        //! \param attachment an optional attached transformation
        TransparentFilter(BufferedTransformation *attachment=NULL) : MeterFilter(attachment, true) {}
};

//! \class OpaqueFilter
//! \brief A non-transparent MeterFilter
//! \sa MeterFilter, TransparentFilter
class CRYPTOPP_DLL OpaqueFilter : public MeterFilter
{
public:
        //! \brief Construct an OpaqueFilter
        //! \param attachment an optional attached transformation
        OpaqueFilter(BufferedTransformation *attachment=NULL) : MeterFilter(attachment, false) {}
};

//! \class FilterWithBufferedInput
//! \brief Divides an input stream into discrete blocks
//! \details FilterWithBufferedInput divides the input stream into a first block, a number of
//!   middle blocks, and a last block. First and last blocks are optional, and middle blocks may
//!   be a stream instead (i.e. <tt>blockSize == 1</tt>).
//! \sa AuthenticatedEncryptionFilter, AuthenticatedDecryptionFilter, HashVerificationFilter,
//!   SignatureVerificationFilter, StreamTransformationFilter
class CRYPTOPP_DLL FilterWithBufferedInput : public Filter
{
public:

#if !defined(CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562)
        //! default FilterWithBufferedInput for temporaries
        FilterWithBufferedInput();
#endif

        //! \brief Construct a FilterWithBufferedInput with an attached transformation
        //! \param attachment an attached transformation
        FilterWithBufferedInput(BufferedTransformation *attachment);

        //! \brief Construct a FilterWithBufferedInput with an attached transformation
        //! \param firstSize the size of the first block
        //! \param blockSize the size of middle blocks
        //! \param lastSize the size of the last block
        //! \param attachment an attached transformation
        //! \details \p firstSize and \p lastSize may be 0. \p blockSize must be at least 1.
        FilterWithBufferedInput(size_t firstSize, size_t blockSize, size_t lastSize, BufferedTransformation *attachment);

        void IsolatedInitialize(const NameValuePairs &parameters);
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
        {
                return PutMaybeModifiable(const_cast<byte *>(inString), length, messageEnd, blocking, false);
        }
        size_t PutModifiable2(byte *inString, size_t length, int messageEnd, bool blocking)
        {
                return PutMaybeModifiable(inString, length, messageEnd, blocking, true);
        }

        //! \brief Flushes data buffered by this object, without signal propagation
        //! \param hardFlush indicates whether all data should be flushed
        //! \param blocking specifies whether the object should block when processing input
        //! \details IsolatedFlush() calls ForceNextPut() if hardFlush is true
        //! \note  hardFlush must be used with care
        bool IsolatedFlush(bool hardFlush, bool blocking);

        //! \brief Flushes data buffered by this object
        //! \details The input buffer may contain more than blockSize bytes if <tt>lastSize != 0</tt>.
        //!   ForceNextPut() forces a call to NextPut() if this is the case.
        void ForceNextPut();

protected:
        virtual bool DidFirstPut() const {return m_firstInputDone;}
        virtual size_t GetFirstPutSize() const {return m_firstSize;}
        virtual size_t GetBlockPutSize() const {return m_blockSize;}
        virtual size_t GetLastPutSize() const {return m_lastSize;}

        virtual void InitializeDerivedAndReturnNewSizes(const NameValuePairs &parameters, size_t &firstSize, size_t &blockSize, size_t &lastSize)
                {CRYPTOPP_UNUSED(parameters); CRYPTOPP_UNUSED(firstSize); CRYPTOPP_UNUSED(blockSize); CRYPTOPP_UNUSED(lastSize); InitializeDerived(parameters);}
        virtual void InitializeDerived(const NameValuePairs &parameters)
                {CRYPTOPP_UNUSED(parameters);}
        // FirstPut() is called if (firstSize != 0 and totalLength >= firstSize)
        // or (firstSize == 0 and (totalLength > 0 or a MessageEnd() is received)).
        // inString is m_firstSize in length.
        virtual void FirstPut(const byte *inString) =0;
        // NextPut() is called if totalLength >= firstSize+blockSize+lastSize
        virtual void NextPutSingle(const byte *inString)
                {CRYPTOPP_UNUSED(inString); CRYPTOPP_ASSERT(false);}
        // Same as NextPut() except length can be a multiple of blockSize
        // Either NextPut() or NextPutMultiple() must be overriden
        virtual void NextPutMultiple(const byte *inString, size_t length);
        // Same as NextPutMultiple(), but inString can be modified
        virtual void NextPutModifiable(byte *inString, size_t length)
                {NextPutMultiple(inString, length);}
        // LastPut() is always called
        // if totalLength < firstSize then length == totalLength
        // else if totalLength <= firstSize+lastSize then length == totalLength-firstSize
        // else lastSize <= length < lastSize+blockSize
        virtual void LastPut(const byte *inString, size_t length) =0;
        virtual void FlushDerived() {}

protected:
        size_t PutMaybeModifiable(byte *begin, size_t length, int messageEnd, bool blocking, bool modifiable);
        void NextPutMaybeModifiable(byte *inString, size_t length, bool modifiable)
        {
                if (modifiable) NextPutModifiable(inString, length);
                else NextPutMultiple(inString, length);
        }

        // This function should no longer be used, put this here to cause a compiler error
        // if someone tries to override NextPut().
        virtual int NextPut(const byte *inString, size_t length)
                {CRYPTOPP_UNUSED(inString); CRYPTOPP_UNUSED(length); CRYPTOPP_ASSERT(false); return 0;}

        class BlockQueue
        {
        public:
                void ResetQueue(size_t blockSize, size_t maxBlocks);
                byte *GetBlock();
                byte *GetContigousBlocks(size_t &numberOfBytes);
                size_t GetAll(byte *outString);
                void Put(const byte *inString, size_t length);
                size_t CurrentSize() const {return m_size;}
                size_t MaxSize() const {return m_buffer.size();}

        private:
                SecByteBlock m_buffer;
                size_t m_blockSize, m_maxBlocks, m_size;
                byte *m_begin;
        };

        size_t m_firstSize, m_blockSize, m_lastSize;
        bool m_firstInputDone;
        BlockQueue m_queue;
};

//! \class FilterWithInputQueue
//! \brief A filter that buffers input using a ByteQueue
//! \details FilterWithInputQueue will buffer input using a ByteQueue. When the filter receives
//!   a \ref BufferedTransformation::MessageEnd() "MessageEnd()" signal it will pass the data
//!   on to its attached transformation.
class CRYPTOPP_DLL FilterWithInputQueue : public Filter
{
public:
        //! \brief Construct a FilterWithInputQueue
        //! \param attachment an optional attached transformation
        FilterWithInputQueue(BufferedTransformation *attachment=NULL) : Filter(attachment) {}

        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
        {
                if (!blocking)
                        throw BlockingInputOnly("FilterWithInputQueue");

                m_inQueue.Put(inString, length);
                if (messageEnd)
                {
                        IsolatedMessageEnd(blocking);
                        Output(0, NULL, 0, messageEnd, blocking);
                }
                return 0;
        }

protected:
        virtual bool IsolatedMessageEnd(bool blocking) =0;
        void IsolatedInitialize(const NameValuePairs &parameters)
                {CRYPTOPP_UNUSED(parameters); m_inQueue.Clear();}

        ByteQueue m_inQueue;
};

//! \struct BlockPaddingSchemeDef
//! \brief Padding schemes used for block ciphers
struct BlockPaddingSchemeDef
{
        //! \enum BlockPaddingScheme
        //! \brief Padding schemes used for block ciphers.
        //! \details DEFAULT_PADDING means PKCS_PADDING if <tt>cipher.MandatoryBlockSize() > 1 &&
        //!   cipher.MinLastBlockSize() == 0</tt>, which holds for ECB or CBC mode. Otherwise,
        //!   NO_PADDING for modes like OFB, CFB, CTR, CBC-CTS.
        //! \sa <A HREF="http://www.weidai.com/scan-mirror/csp.html">Block Cipher Padding</A> for
        //!   additional details.
        enum BlockPaddingScheme {
                //! \brief No padding added to a block
                NO_PADDING,
                //! \brief 0's padding added to a block
                ZEROS_PADDING,
                //! \brief PKCS #5 padding added to a block
                PKCS_PADDING,
                //! \brief 1 and 0's padding added to a block
                ONE_AND_ZEROS_PADDING,
                //! \brief Default padding scheme
                DEFAULT_PADDING
        };
};

//! \class StreamTransformationFilter
//! \brief Filter wrapper for StreamTransformation
//! \details Filter wrapper for StreamTransformation. The filter will optionally handle padding/unpadding when needed
class CRYPTOPP_DLL StreamTransformationFilter : public FilterWithBufferedInput, public BlockPaddingSchemeDef, private FilterPutSpaceHelper
{
public:
        //! \brief Construct a StreamTransformationFilter
        //! \param c reference to a StreamTransformation
        //! \param attachment an optional attached transformation
        //! \param padding the \ref BlockPaddingSchemeDef "padding scheme"
        //! \param allowAuthenticatedSymmetricCipher flag indicating whether the filter should allow authenticated encryption schemes
        StreamTransformationFilter(StreamTransformation &c, BufferedTransformation *attachment = NULL, BlockPaddingScheme padding = DEFAULT_PADDING, bool allowAuthenticatedSymmetricCipher = false);

        std::string AlgorithmName() const {return m_cipher.AlgorithmName();}

protected:
        void InitializeDerivedAndReturnNewSizes(const NameValuePairs &parameters, size_t &firstSize, size_t &blockSize, size_t &lastSize);
        void FirstPut(const byte *inString);
        void NextPutMultiple(const byte *inString, size_t length);
        void NextPutModifiable(byte *inString, size_t length);
        void LastPut(const byte *inString, size_t length);

        static size_t LastBlockSize(StreamTransformation &c, BlockPaddingScheme padding);

        StreamTransformation &m_cipher;
        BlockPaddingScheme m_padding;
        unsigned int m_optimalBufferSize;
};

#ifdef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY
typedef StreamTransformationFilter StreamCipherFilter;
#endif

//! \class HashFilter
//! \brief Filter wrapper for HashTransformation
class CRYPTOPP_DLL HashFilter : public Bufferless<Filter>, private FilterPutSpaceHelper
{
public:
        //! \brief Construct a HashFilter
        //! \param hm reference to a HashTransformation
        //! \param attachment an optional attached transformation
        //! \param putMessage flag indicating whether the original message should be passed to an attached transformation
        //! \param truncatedDigestSize the size of the digest
        //! \param messagePutChannel the channel on which the message should be output
        //! \param hashPutChannel the channel on which the digest should be output
        HashFilter(HashTransformation &hm, BufferedTransformation *attachment = NULL, bool putMessage=false, int truncatedDigestSize=-1, const std::string &messagePutChannel=DEFAULT_CHANNEL, const std::string &hashPutChannel=DEFAULT_CHANNEL);

        std::string AlgorithmName() const {return m_hashModule.AlgorithmName();}
        void IsolatedInitialize(const NameValuePairs &parameters);
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);
        byte * CreatePutSpace(size_t &size) {return m_hashModule.CreateUpdateSpace(size);}

private:
        HashTransformation &m_hashModule;
        bool m_putMessage;
        unsigned int m_digestSize;
        byte *m_space;
        std::string m_messagePutChannel, m_hashPutChannel;
};

//! \class HashVerificationFilter
//! \brief Filter wrapper for HashTransformation
class CRYPTOPP_DLL HashVerificationFilter : public FilterWithBufferedInput
{
public:
        //! \class HashVerificationFailed
        //! \brief Exception thrown when a data integrity check failure is encountered
        class HashVerificationFailed : public Exception
        {
        public:
                HashVerificationFailed()
                        : Exception(DATA_INTEGRITY_CHECK_FAILED, "HashVerificationFilter: message hash or MAC not valid") {}
        };

        //! \enum Flags
        //! \brief Flags controlling filter behavior.
        //! \details The flags are a bitmask and can be OR'd together.
        enum Flags {
                //! \brief Indicates the hash is at the end of the message (i.e., concatenation of message+hash)
                HASH_AT_END=0,
                //! \brief Indicates the hash is at the beginning of the message (i.e., concatenation of hash+message)
                HASH_AT_BEGIN=1,
                //! \brief Indicates the message should be passed to an attached transformation
                PUT_MESSAGE=2,
                //! \brief Indicates the hash should be passed to an attached transformation
                PUT_HASH=4,
                //! \brief Indicates the result of the verification should be passed to an attached transformation
                PUT_RESULT=8,
                //! \brief Indicates the filter should throw a HashVerificationFailed if a failure is encountered
                THROW_EXCEPTION=16,
                //! \brief Default flags using \p HASH_AT_BEGIN and \p PUT_RESULT
                DEFAULT_FLAGS = HASH_AT_BEGIN | PUT_RESULT
        };

        //! \brief Construct a HashVerificationFilter
        //! \param hm reference to a HashTransformation
        //! \param attachment an optional attached transformation
        //! \param flags flags indicating behaviors for the filter
        //! \param truncatedDigestSize the size of the digest
        //! \details <tt>truncatedDigestSize = -1</tt> indicates \ref HashTransformation::DigestSize() "DigestSize" should be used.
        HashVerificationFilter(HashTransformation &hm, BufferedTransformation *attachment = NULL, word32 flags = DEFAULT_FLAGS, int truncatedDigestSize=-1);

        std::string AlgorithmName() const {return m_hashModule.AlgorithmName();}
        bool GetLastResult() const {return m_verified;}

protected:
        void InitializeDerivedAndReturnNewSizes(const NameValuePairs &parameters, size_t &firstSize, size_t &blockSize, size_t &lastSize);
        void FirstPut(const byte *inString);
        void NextPutMultiple(const byte *inString, size_t length);
        void LastPut(const byte *inString, size_t length);

private:
        friend class AuthenticatedDecryptionFilter;

        HashTransformation &m_hashModule;
        word32 m_flags;
        unsigned int m_digestSize;
        bool m_verified;
        SecByteBlock m_expectedHash;
};

typedef HashVerificationFilter HashVerifier;    // for backwards compatibility

//! \class AuthenticatedEncryptionFilter
//! \brief Filter wrapper for encrypting with AuthenticatedSymmetricCipher
//! \details Filter wrapper for encrypting with AuthenticatedSymmetricCipher, optionally handling padding/unpadding when needed
class CRYPTOPP_DLL AuthenticatedEncryptionFilter : public StreamTransformationFilter
{
public:
        //! \brief Construct a AuthenticatedEncryptionFilter
        //! \param c reference to a AuthenticatedSymmetricCipher
        //! \param attachment an optional attached transformation
        //! \param putAAD flag indicating whether the AAD should be passed to an attached transformation
        //! \param truncatedDigestSize the size of the digest
        //! \param macChannel the channel on which the MAC should be output
        //! \param padding the \ref BlockPaddingSchemeDef "padding scheme"
        //! \details <tt>truncatedDigestSize = -1</tt> indicates \ref HashTransformation::DigestSize() "DigestSize" should be used.
        AuthenticatedEncryptionFilter(AuthenticatedSymmetricCipher &c, BufferedTransformation *attachment = NULL, bool putAAD=false, int truncatedDigestSize=-1, const std::string &macChannel=DEFAULT_CHANNEL, BlockPaddingScheme padding = DEFAULT_PADDING);

        void IsolatedInitialize(const NameValuePairs &parameters);
        byte * ChannelCreatePutSpace(const std::string &channel, size_t &size);
        size_t ChannelPut2(const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking);
        void LastPut(const byte *inString, size_t length);

protected:
        HashFilter m_hf;
};

//! \class AuthenticatedDecryptionFilter
//! \brief Filter wrapper for decrypting with AuthenticatedSymmetricCipher
//! \details Filter wrapper wrapper for decrypting with AuthenticatedSymmetricCipher, optionally handling padding/unpadding when needed.
class CRYPTOPP_DLL AuthenticatedDecryptionFilter : public FilterWithBufferedInput, public BlockPaddingSchemeDef
{
public:
        //! \enum Flags
        //! \brief Flags controlling filter behavior.
        //! \details The flags are a bitmask and can be OR'd together.
        enum Flags {
                //! \brief Indicates the MAC is at the end of the message (i.e., concatenation of message+mac)
                MAC_AT_END=0,
                //! \brief Indicates the MAC is at the beginning of the message (i.e., concatenation of mac+message)
                MAC_AT_BEGIN=1,
                //! \brief Indicates the filter should throw a HashVerificationFailed if a failure is encountered
                THROW_EXCEPTION=16,
                //! \brief Default flags using \p THROW_EXCEPTION
                DEFAULT_FLAGS = THROW_EXCEPTION
        };

        //! \brief Construct a AuthenticatedDecryptionFilter
        //! \param c reference to a AuthenticatedSymmetricCipher
        //! \param attachment an optional attached transformation
        //! \param flags flags indicating behaviors for the filter
        //! \param truncatedDigestSize the size of the digest
        //! \param padding the \ref BlockPaddingSchemeDef "padding scheme"
        //! \details Additional authenticated data should be given in channel "AAD".
        //! \details <tt>truncatedDigestSize = -1</tt> indicates \ref HashTransformation::DigestSize() "DigestSize" should be used.
        AuthenticatedDecryptionFilter(AuthenticatedSymmetricCipher &c, BufferedTransformation *attachment = NULL, word32 flags = DEFAULT_FLAGS, int truncatedDigestSize=-1, BlockPaddingScheme padding = DEFAULT_PADDING);

        std::string AlgorithmName() const {return m_hashVerifier.AlgorithmName();}
        byte * ChannelCreatePutSpace(const std::string &channel, size_t &size);
        size_t ChannelPut2(const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking);
        bool GetLastResult() const {return m_hashVerifier.GetLastResult();}

protected:
        void InitializeDerivedAndReturnNewSizes(const NameValuePairs &parameters, size_t &firstSize, size_t &blockSize, size_t &lastSize);
        void FirstPut(const byte *inString);
        void NextPutMultiple(const byte *inString, size_t length);
        void LastPut(const byte *inString, size_t length);

        HashVerificationFilter m_hashVerifier;
        StreamTransformationFilter m_streamFilter;
};

//! \class SignerFilter
//! \brief Filter wrapper for PK_Signer
class CRYPTOPP_DLL SignerFilter : public Unflushable<Filter>
{
public:
        //! \brief Construct a SignerFilter
        //! \param rng a RandomNumberGenerator derived class
        //! \param signer a PK_Signer derived class
        //! \param attachment an optional attached transformation
        //! \param putMessage flag indicating whether the original message should be passed to an attached transformation
        SignerFilter(RandomNumberGenerator &rng, const PK_Signer &signer, BufferedTransformation *attachment = NULL, bool putMessage=false)
                : m_rng(rng), m_signer(signer), m_messageAccumulator(signer.NewSignatureAccumulator(rng)), m_putMessage(putMessage) {Detach(attachment);}

        std::string AlgorithmName() const {return m_signer.AlgorithmName();}

        void IsolatedInitialize(const NameValuePairs &parameters);
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);

private:
        RandomNumberGenerator &m_rng;
        const PK_Signer &m_signer;
        member_ptr<PK_MessageAccumulator> m_messageAccumulator;
        bool m_putMessage;
        SecByteBlock m_buf;
};

//! \class SignatureVerificationFilter
//! \brief Filter wrapper for PK_Verifier
class CRYPTOPP_DLL SignatureVerificationFilter : public FilterWithBufferedInput
{
public:
        //! \brief Exception thrown when an invalid signature is encountered
        class SignatureVerificationFailed : public Exception
        {
        public:
                SignatureVerificationFailed()
                        : Exception(DATA_INTEGRITY_CHECK_FAILED, "VerifierFilter: digital signature not valid") {}
        };

        //! \enum Flags
        //! \brief Flags controlling filter behavior.
        //! \details The flags are a bitmask and can be OR'd together.
        enum Flags {
                //! \brief Indicates the signature is at the end of the message (i.e., concatenation of message+signature)
                SIGNATURE_AT_END=0,
                //! \brief Indicates the signature is at the beginning of the message (i.e., concatenation of signature+message)
                SIGNATURE_AT_BEGIN=1,
                //! \brief Indicates the message should be passed to an attached transformation
                PUT_MESSAGE=2,
                //! \brief Indicates the signature should be passed to an attached transformation
                PUT_SIGNATURE=4,
                //! \brief Indicates the result of the verification should be passed to an attached transformation
                PUT_RESULT=8,
                //! \brief Indicates the filter should throw a HashVerificationFailed if a failure is encountered
                THROW_EXCEPTION=16,
                //! \brief Default flags using \p SIGNATURE_AT_BEGIN and \p PUT_RESULT
                DEFAULT_FLAGS = SIGNATURE_AT_BEGIN | PUT_RESULT
        };

        //! \brief Construct a SignatureVerificationFilter
        //! \param verifier a PK_Verifier derived class
        //! \param attachment an optional attached transformation
        //! \param flags flags indicating behaviors for the filter
        SignatureVerificationFilter(const PK_Verifier &verifier, BufferedTransformation *attachment = NULL, word32 flags = DEFAULT_FLAGS);

        std::string AlgorithmName() const {return m_verifier.AlgorithmName();}

        //! \brief Retrieves the result of the last verification
        //! \returns true if the signature on the previosus message was valid, false otherwise
        bool GetLastResult() const {return m_verified;}

protected:
        void InitializeDerivedAndReturnNewSizes(const NameValuePairs &parameters, size_t &firstSize, size_t &blockSize, size_t &lastSize);
        void FirstPut(const byte *inString);
        void NextPutMultiple(const byte *inString, size_t length);
        void LastPut(const byte *inString, size_t length);

private:
        const PK_Verifier &m_verifier;
        member_ptr<PK_MessageAccumulator> m_messageAccumulator;
        word32 m_flags;
        SecByteBlock m_signature;
        bool m_verified;
};

typedef SignatureVerificationFilter VerifierFilter;     // for backwards compatibility

//! \class Redirector
//! \brief Redirect input to another BufferedTransformation without owning it
class CRYPTOPP_DLL Redirector : public CustomSignalPropagation<Sink>
{
public:
        //! \enum Behavior
        //! \brief Controls signal propagation behavior
        enum Behavior
        {
                //! \brief Pass data only
                DATA_ONLY = 0x00,
                //! \brief Pass signals
                PASS_SIGNALS = 0x01,
                //! \brief Pass wait events
                PASS_WAIT_OBJECTS = 0x02,
                //! \brief Pass everything
                //! \details PASS_EVERYTHING is default
                PASS_EVERYTHING = PASS_SIGNALS | PASS_WAIT_OBJECTS
        };

        //! \brief Construct a Redirector
        Redirector() : m_target(NULL), m_behavior(PASS_EVERYTHING) {}

        //! \brief Construct a Redirector
        //! \param target the destination BufferedTransformation
        //! \param behavior \ref Behavior "flags" specifying signal propagation
        Redirector(BufferedTransformation &target, Behavior behavior=PASS_EVERYTHING)
                : m_target(&target), m_behavior(behavior) {}

        //! \brief Redirect input to another BufferedTransformation
        //! \param target the destination BufferedTransformation
        void Redirect(BufferedTransformation &target) {m_target = &target;}
        //! \brief Stop redirecting input
        void StopRedirection() {m_target = NULL;}

        Behavior GetBehavior() {return (Behavior) m_behavior;}
        void SetBehavior(Behavior behavior) {m_behavior=behavior;}
        bool GetPassSignals() const {return (m_behavior & PASS_SIGNALS) != 0;}
        void SetPassSignals(bool pass) { if (pass) m_behavior |= PASS_SIGNALS; else m_behavior &= ~(word32) PASS_SIGNALS; }
        bool GetPassWaitObjects() const {return (m_behavior & PASS_WAIT_OBJECTS) != 0;}
        void SetPassWaitObjects(bool pass) { if (pass) m_behavior |= PASS_WAIT_OBJECTS; else m_behavior &= ~(word32) PASS_WAIT_OBJECTS; }

        bool CanModifyInput() const
                {return m_target ? m_target->CanModifyInput() : false;}

        void Initialize(const NameValuePairs &parameters, int propagation);
        byte * CreatePutSpace(size_t &size)
        {
                if (m_target)
                        return m_target->CreatePutSpace(size);
                else
                {
                        size = 0;
                        return NULL;
                }
        }
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
                {return m_target ? m_target->Put2(inString, length, GetPassSignals() ? messageEnd : 0, blocking) : 0;}
        bool Flush(bool hardFlush, int propagation=-1, bool blocking=true)
                {return m_target && GetPassSignals() ? m_target->Flush(hardFlush, propagation, blocking) : false;}
        bool MessageSeriesEnd(int propagation=-1, bool blocking=true)
                {return m_target && GetPassSignals() ? m_target->MessageSeriesEnd(propagation, blocking) : false;}

        byte * ChannelCreatePutSpace(const std::string &channel, size_t &size)
        {
                if (m_target)
                        return m_target->ChannelCreatePutSpace(channel, size);
                else
                {
                        size = 0;
                        return NULL;
                }
        }
        size_t ChannelPut2(const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking)
                {return m_target ? m_target->ChannelPut2(channel, begin, length, GetPassSignals() ? messageEnd : 0, blocking) : 0;}
        size_t ChannelPutModifiable2(const std::string &channel, byte *begin, size_t length, int messageEnd, bool blocking)
                {return m_target ? m_target->ChannelPutModifiable2(channel, begin, length, GetPassSignals() ? messageEnd : 0, blocking) : 0;}
        bool ChannelFlush(const std::string &channel, bool completeFlush, int propagation=-1, bool blocking=true)
                {return m_target && GetPassSignals() ? m_target->ChannelFlush(channel, completeFlush, propagation, blocking) : false;}
        bool ChannelMessageSeriesEnd(const std::string &channel, int propagation=-1, bool blocking=true)
                {return m_target && GetPassSignals() ? m_target->ChannelMessageSeriesEnd(channel, propagation, blocking) : false;}

        unsigned int GetMaxWaitObjectCount() const
                { return m_target && GetPassWaitObjects() ? m_target->GetMaxWaitObjectCount() : 0; }
        void GetWaitObjects(WaitObjectContainer &container, CallStack const& callStack)
                { if (m_target && GetPassWaitObjects()) m_target->GetWaitObjects(container, callStack); }

private:
        BufferedTransformation *m_target;
        word32 m_behavior;
};

// Used By ProxyFilter
class CRYPTOPP_DLL OutputProxy : public CustomSignalPropagation<Sink>
{
public:
        OutputProxy(BufferedTransformation &owner, bool passSignal) : m_owner(owner), m_passSignal(passSignal) {}

        bool GetPassSignal() const {return m_passSignal;}
        void SetPassSignal(bool passSignal) {m_passSignal = passSignal;}

        byte * CreatePutSpace(size_t &size)
                {return m_owner.AttachedTransformation()->CreatePutSpace(size);}
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
                {return m_owner.AttachedTransformation()->Put2(inString, length, m_passSignal ? messageEnd : 0, blocking);}
        size_t PutModifiable2(byte *begin, size_t length, int messageEnd, bool blocking)
                {return m_owner.AttachedTransformation()->PutModifiable2(begin, length, m_passSignal ? messageEnd : 0, blocking);}
        void Initialize(const NameValuePairs &parameters=g_nullNameValuePairs, int propagation=-1)
                {if (m_passSignal) m_owner.AttachedTransformation()->Initialize(parameters, propagation);}
        bool Flush(bool hardFlush, int propagation=-1, bool blocking=true)
                {return m_passSignal ? m_owner.AttachedTransformation()->Flush(hardFlush, propagation, blocking) : false;}
        bool MessageSeriesEnd(int propagation=-1, bool blocking=true)
                {return m_passSignal ? m_owner.AttachedTransformation()->MessageSeriesEnd(propagation, blocking) : false;}

        byte * ChannelCreatePutSpace(const std::string &channel, size_t &size)
                {return m_owner.AttachedTransformation()->ChannelCreatePutSpace(channel, size);}
        size_t ChannelPut2(const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking)
                {return m_owner.AttachedTransformation()->ChannelPut2(channel, begin, length, m_passSignal ? messageEnd : 0, blocking);}
        size_t ChannelPutModifiable2(const std::string &channel, byte *begin, size_t length, int messageEnd, bool blocking)
                {return m_owner.AttachedTransformation()->ChannelPutModifiable2(channel, begin, length, m_passSignal ? messageEnd : 0, blocking);}
        bool ChannelFlush(const std::string &channel, bool completeFlush, int propagation=-1, bool blocking=true)
                {return m_passSignal ? m_owner.AttachedTransformation()->ChannelFlush(channel, completeFlush, propagation, blocking) : false;}
        bool ChannelMessageSeriesEnd(const std::string &channel, int propagation=-1, bool blocking=true)
                {return m_passSignal ? m_owner.AttachedTransformation()->ChannelMessageSeriesEnd(channel, propagation, blocking) : false;}

private:
        BufferedTransformation &m_owner;
        bool m_passSignal;
};

//! \class ProxyFilter
//! \brief Base class for Filter classes that are proxies for a chain of other filters
class CRYPTOPP_DLL ProxyFilter : public FilterWithBufferedInput
{
public:
        //! \brief Construct a ProxyFilter
        //! \param filter an output filter
        //! \param firstSize the first Put size
        //! \param lastSize the last Put size
        //! \param attachment an attached transformation
        ProxyFilter(BufferedTransformation *filter, size_t firstSize, size_t lastSize, BufferedTransformation *attachment);

        bool IsolatedFlush(bool hardFlush, bool blocking);

        //! \brief Sets the OutputProxy filter
        //! \param filter an OutputProxy filter
        void SetFilter(Filter *filter);
        void NextPutMultiple(const byte *s, size_t len);
        void NextPutModifiable(byte *inString, size_t length);

protected:
        member_ptr<BufferedTransformation> m_filter;
};

//! \class SimpleProxyFilter
//! \brief Proxy filter that doesn't modify the underlying filter's input or output
class CRYPTOPP_DLL SimpleProxyFilter : public ProxyFilter
{
public:
        //! \brief Construct a SimpleProxyFilter
        //! \param filter an output filter
        //! \param attachment an attached transformation
        SimpleProxyFilter(BufferedTransformation *filter, BufferedTransformation *attachment)
                : ProxyFilter(filter, 0, 0, attachment) {}

        void FirstPut(const byte * inString)
                {CRYPTOPP_UNUSED(inString);}
        void LastPut(const byte *inString, size_t length)
                {CRYPTOPP_UNUSED(inString), CRYPTOPP_UNUSED(length); m_filter->MessageEnd();}
};

//! \class PK_EncryptorFilter
//! \brief Filter wrapper for PK_Encryptor
//! \details PK_DecryptorFilter is a proxy for the filter created by PK_Encryptor::CreateEncryptionFilter.
//!   This class provides symmetry with VerifierFilter.
class CRYPTOPP_DLL PK_EncryptorFilter : public SimpleProxyFilter
{
public:
        //! \brief Construct a PK_EncryptorFilter
        //! \param rng a RandomNumberGenerator derived class
        //! \param encryptor a PK_Encryptor derived class
        //! \param attachment an optional attached transformation
        PK_EncryptorFilter(RandomNumberGenerator &rng, const PK_Encryptor &encryptor, BufferedTransformation *attachment = NULL)
                : SimpleProxyFilter(encryptor.CreateEncryptionFilter(rng), attachment) {}
};

//! \class PK_DecryptorFilter
//! \brief Filter wrapper for PK_Decryptor
//! \details PK_DecryptorFilter is a proxy for the filter created by PK_Decryptor::CreateDecryptionFilter.
//!   This class provides symmetry with SignerFilter.
class CRYPTOPP_DLL PK_DecryptorFilter : public SimpleProxyFilter
{
public:
        //! \brief Construct a PK_DecryptorFilter
        //! \param rng a RandomNumberGenerator derived class
        //! \param decryptor a PK_Decryptor derived class
        //! \param attachment an optional attached transformation
        PK_DecryptorFilter(RandomNumberGenerator &rng, const PK_Decryptor &decryptor, BufferedTransformation *attachment = NULL)
                : SimpleProxyFilter(decryptor.CreateDecryptionFilter(rng), attachment) {}
};

//! \class StringSinkTemplate
//! \brief Append input to a string object
//! \tparam T std::basic_string<char> type
//! \details \ref StringSinkTemplate "StringSink" is a StringSinkTemplate typedef
template <class T>
class StringSinkTemplate : public Bufferless<Sink>
{
public:
        // VC60 workaround: no T::char_type
        typedef typename T::traits_type::char_type char_type;

        //! \brief Construct a StringSinkTemplate
        //! \param output std::basic_string<char> type
        StringSinkTemplate(T &output)
                : m_output(&output) {CRYPTOPP_ASSERT(sizeof(output[0])==1);}

        void IsolatedInitialize(const NameValuePairs &parameters)
                {if (!parameters.GetValue("OutputStringPointer", m_output)) throw InvalidArgument("StringSink: OutputStringPointer not specified");}

        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
        {
                CRYPTOPP_UNUSED(messageEnd); CRYPTOPP_UNUSED(blocking);
                if (length > 0)
                {
                        typename T::size_type size = m_output->size();
                        if (length < size && size + length > m_output->capacity())
                                m_output->reserve(2*size);
                        m_output->append((const char_type *)inString, (const char_type *)inString+length);
                }
                return 0;
        }

private:
        T *m_output;
};

CRYPTOPP_DLL_TEMPLATE_CLASS StringSinkTemplate<std::string>;
DOCUMENTED_TYPEDEF(StringSinkTemplate<std::string>, StringSink);

//! \class RandomNumberSink
//! \brief Incorporates input into RNG as additional entropy
class RandomNumberSink : public Bufferless<Sink>
{
public:
        //! \brief Construct a RandomNumberSink
        RandomNumberSink()
                : m_rng(NULL) {}

        //! \brief Construct a RandomNumberSink
        //! \param rng a RandomNumberGenerator derived class
        RandomNumberSink(RandomNumberGenerator &rng)
                : m_rng(&rng) {}

        void IsolatedInitialize(const NameValuePairs &parameters);
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);

private:
        RandomNumberGenerator *m_rng;
};

//! \class ArraySink
//! \brief Copy input to a memory buffer
class CRYPTOPP_DLL ArraySink : public Bufferless<Sink>
{
public:
        //! \brief Construct an ArraySink
        //! \param parameters a set of NameValuePairs to initialize this object
        //! \details Name::OutputBuffer() is a mandatory parameter using this constructor.
        ArraySink(const NameValuePairs &parameters = g_nullNameValuePairs)
                : m_buf(NULL), m_size(0), m_total(0) {IsolatedInitialize(parameters);}

        //! \brief Construct an ArraySink
        //! \param buf pointer to a memory buffer
        //! \param size length of the memory buffer
        ArraySink(byte *buf, size_t size)
                : m_buf(buf), m_size(size), m_total(0) {}

        //! \brief Provides the size remaining in the Sink
        //! \returns size remaining in the Sink, in bytes
        size_t AvailableSize() {return SaturatingSubtract(m_size, m_total);}

        //! \brief Provides the number of bytes written to the Sink
        //! \returns number of bytes written to the Sink, in bytes
        lword TotalPutLength() {return m_total;}

        void IsolatedInitialize(const NameValuePairs &parameters);
        byte * CreatePutSpace(size_t &size);
        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);

protected:
        byte *m_buf;
        size_t m_size;
        lword m_total;
};

//! \class ArrayXorSink
//! \brief Xor input to a memory buffer
class CRYPTOPP_DLL ArrayXorSink : public ArraySink
{
public:
        //! \brief Construct an ArrayXorSink
        //! \param buf pointer to a memory buffer
        //! \param size length of the memory buffer
        ArrayXorSink(byte *buf, size_t size)
                : ArraySink(buf, size) {}

        size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);
        byte * CreatePutSpace(size_t &size) {return BufferedTransformation::CreatePutSpace(size);}
};

//! \class StringStore
//! \brief String-based implementation of Store interface
class StringStore : public Store
{
public:
        //! \brief Construct a StringStore
        //! \param string pointer to a C-String
        StringStore(const char *string = NULL)
                {StoreInitialize(MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}

        //! \brief Construct a StringStore
        //! \param string pointer to a memory buffer
        //! \param length size of the memory buffer
        StringStore(const byte *string, size_t length)
                {StoreInitialize(MakeParameters("InputBuffer", ConstByteArrayParameter(string, length)));}

        //! \brief Construct a StringStore
        //! \tparam T std::basic_string<char> type
        //! \param string reference to a std::basic_string<char> type
        template <class T> StringStore(const T &string)
                {StoreInitialize(MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}

        CRYPTOPP_DLL size_t TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true);
        CRYPTOPP_DLL size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const;

private:
        CRYPTOPP_DLL void StoreInitialize(const NameValuePairs &parameters);

        const byte *m_store;
        size_t m_length, m_count;
};

//! RNG-based implementation of Source interface
class CRYPTOPP_DLL RandomNumberStore : public Store
{
public:
        RandomNumberStore()
                : m_rng(NULL), m_length(0), m_count(0) {}

        RandomNumberStore(RandomNumberGenerator &rng, lword length)
                : m_rng(&rng), m_length(length), m_count(0) {}

        bool AnyRetrievable() const {return MaxRetrievable() != 0;}
        lword MaxRetrievable() const {return m_length-m_count;}

        size_t TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true);
        size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const
        {
                CRYPTOPP_UNUSED(target); CRYPTOPP_UNUSED(begin); CRYPTOPP_UNUSED(end); CRYPTOPP_UNUSED(channel); CRYPTOPP_UNUSED(blocking);
                throw NotImplemented("RandomNumberStore: CopyRangeTo2() is not supported by this store");
        }

private:
        void StoreInitialize(const NameValuePairs &parameters);

        RandomNumberGenerator *m_rng;
        lword m_length, m_count;
};

//! empty store
class CRYPTOPP_DLL NullStore : public Store
{
public:
        NullStore(lword size = ULONG_MAX) : m_size(size) {}
        void StoreInitialize(const NameValuePairs &parameters)
                {CRYPTOPP_UNUSED(parameters);}
        lword MaxRetrievable() const {return m_size;}
        size_t TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true);
        size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=DEFAULT_CHANNEL, bool blocking=true) const;

private:
        lword m_size;
};

//! \class Source
//! \brief Implementation of BufferedTransformation's attachment interface
//! \details Source 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 \a 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.
//! \details See the discussion of BufferedTransformation in cryptlib.h for
//!   more details.
//! \sa Store and SourceTemplate
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Source : public InputRejecting<Filter>
{
public:
#ifndef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562
        virtual ~Source() {}
#endif

        //! \brief Construct a Source
        //! \param attachment an optional attached transformation
        Source(BufferedTransformation *attachment = NULL)
                {Source::Detach(attachment);}

        //!     \name PIPELINE
        //@{

        //! \brief Pump data to attached transformation
        //! \param pumpMax the maximpum number of bytes to pump
        //! \returns the number of bytes that remain in the block (i.e., bytes not processed)
        //! \details Internally, Pump() calls Pump2().
        //! \note pumpMax is a \p lword, which is a 64-bit value that typically uses \p LWORD_MAX. The default
        //!   argument is a \p size_t that uses \p SIZE_MAX, and it can be 32-bits or 64-bits.
        lword Pump(lword pumpMax=(size_t)SIZE_MAX)
                {Pump2(pumpMax); return pumpMax;}

        //! \brief Pump messages to attached transformation
        //! \param count the maximpum number of messages to pump
        //! \returns TODO
        //! \details Internally, PumpMessages() calls PumpMessages2().
        unsigned int PumpMessages(unsigned int count=UINT_MAX)
                {PumpMessages2(count); return count;}

        //! \brief Pump all data to attached transformation
        //! \details Internally, PumpAll() calls PumpAll2().
        void PumpAll()
                {PumpAll2();}

        //! \brief Pump data to attached transformation
        //! \param byteCount the maximpum number of bytes to pump
        //! \param blocking specifies whether the object should block when processing input
        //! \returns the number of bytes that remain in the block (i.e., bytes not processed)
        //! \details byteCount is an \a IN and \a OUT parameter. When the call is made, byteCount is the
        //!   requested size of the pump. When the call returns, byteCount is the number of bytes that
        //!   were pumped.
        virtual size_t Pump2(lword &byteCount, bool blocking=true) =0;

        //! \brief Pump messages to attached transformation
        //! \param messageCount the maximpum number of messages to pump
        //! \param blocking specifies whether the object should block when processing input
        //! \details messageCount is an IN and OUT parameter.
        virtual size_t PumpMessages2(unsigned int &messageCount, bool blocking=true) =0;

        //! \brief Pump all data to attached transformation
        //! \param blocking specifies whether the object should block when processing input
        //! \returns the number of bytes that remain in the block (i.e., bytes not processed)
        virtual size_t PumpAll2(bool blocking=true);

        //! \brief Determines if the Source is exhausted
        //! \returns true if the source has been exhausted
        virtual bool SourceExhausted() const =0;

        //@}

protected:
        void SourceInitialize(bool pumpAll, const NameValuePairs &parameters)
        {
                IsolatedInitialize(parameters);
                if (pumpAll)
                        PumpAll();
        }
};

//! \class SourceTemplate
//! \brief Transform a Store into a Source
//! \tparam T the class or type
template <class T>
class SourceTemplate : public Source
{
public:
        //! \brief Construct a SourceTemplate
        //! \tparam T the class or type
        //! \param attachment an attached transformation
        SourceTemplate<T>(BufferedTransformation *attachment)
                : Source(attachment) {}
        void IsolatedInitialize(const NameValuePairs &parameters)
                {m_store.IsolatedInitialize(parameters);}
        size_t Pump2(lword &byteCount, bool blocking=true)
                {return m_store.TransferTo2(*AttachedTransformation(), byteCount, DEFAULT_CHANNEL, blocking);}
        size_t PumpMessages2(unsigned int &messageCount, bool blocking=true)
                {return m_store.TransferMessagesTo2(*AttachedTransformation(), messageCount, DEFAULT_CHANNEL, blocking);}
        size_t PumpAll2(bool blocking=true)
                {return m_store.TransferAllTo2(*AttachedTransformation(), DEFAULT_CHANNEL, blocking);}
        bool SourceExhausted() const
                {return !m_store.AnyRetrievable() && !m_store.AnyMessages();}
        void SetAutoSignalPropagation(int propagation)
                {m_store.SetAutoSignalPropagation(propagation);}
        int GetAutoSignalPropagation() const
                {return m_store.GetAutoSignalPropagation();}

protected:
        T m_store;
};

//! \class SourceTemplate
//! \brief String-based implementation of the Source interface
class CRYPTOPP_DLL StringSource : public SourceTemplate<StringStore>
{
public:
        //! \brief Construct a StringSource
        //! \param attachment an optional attached transformation
        StringSource(BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {}

        //! \brief Construct a StringSource
        //! \param string C-String
        //! \param pumpAll C-String
        //! \param attachment an optional attached transformation
        StringSource(const char *string, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {SourceInitialize(pumpAll, MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}
        //! binary byte array as source
        StringSource(const byte *string, size_t length, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {SourceInitialize(pumpAll, MakeParameters("InputBuffer", ConstByteArrayParameter(string, length)));}
        //! std::string as source
        StringSource(const std::string &string, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {SourceInitialize(pumpAll, MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}
};

// Use the third constructor for an array source
DOCUMENTED_TYPEDEF(StringSource, ArraySource);

//! RNG-based implementation of Source interface
class CRYPTOPP_DLL RandomNumberSource : public SourceTemplate<RandomNumberStore>
{
public:
        RandomNumberSource(RandomNumberGenerator &rng, int length, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<RandomNumberStore>(attachment)
                {SourceInitialize(pumpAll, MakeParameters("RandomNumberGeneratorPointer", &rng)("RandomNumberStoreSize", length));}
};

NAMESPACE_END

#if CRYPTOPP_MSC_VERSION
# pragma warning(pop)
#endif

#endif