filters.h

#ifndef CRYPTOPP_FILTERS_H
#define CRYPTOPP_FILTERS_H

#include "simple.h"
#include "secblock.h"
#include "misc.h"
#include "smartptr.h"
#include "queue.h"
#include "algparam.h"
#include <deque>

NAMESPACE_BEGIN(CryptoPP)

/// provides an implementation of BufferedTransformation's attachment interface
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Filter : public BufferedTransformation, public NotCopyable
{
public:
        Filter(BufferedTransformation *attachment = NULL);

        bool Attachable() {return true;}
        BufferedTransformation *AttachedTransformation();
        const BufferedTransformation *AttachedTransformation() const;
        void Detach(BufferedTransformation *newAttachment = NULL);

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

        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);

        size_t Output(int outputSite, const byte *inString, size_t length, int messageEnd, bool blocking, const std::string &channel=NULL_CHANNEL);
        size_t OutputModifiable(int outputSite, byte *inString, size_t length, int messageEnd, bool blocking, const std::string &channel=NULL_CHANNEL);
        bool OutputMessageEnd(int outputSite, int propagation, bool blocking, const std::string &channel=NULL_CHANNEL);
        bool OutputFlush(int outputSite, bool hardFlush, int propagation, bool blocking, const std::string &channel=NULL_CHANNEL);
        bool OutputMessageSeriesEnd(int outputSite, int propagation, bool blocking, const std::string &channel=NULL_CHANNEL);

private:
        member_ptr<BufferedTransformation> m_attachment;
        
protected:
        size_t m_inputPosition;
        int m_continueAt;
};

struct CRYPTOPP_DLL FilterPutSpaceHelper
{
        // desiredSize is how much to ask target, bufferSize is how much to allocate in m_tempSpace
        byte *HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize, size_t desiredSize, size_t &bufferSize)
        {
                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();
        }
        byte *HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize)
                {return HelpCreatePutSpace(target, channel, minSize, minSize, minSize);}
        byte *HelpCreatePutSpace(BufferedTransformation &target, const std::string &channel, size_t minSize, size_t bufferSize)
                {return HelpCreatePutSpace(target, channel, minSize, minSize, bufferSize);}
        SecByteBlock m_tempSpace;
};

//! measure how many byte and messages pass through, also serves as valve
class CRYPTOPP_DLL MeterFilter : public Bufferless<Filter>
{
public:
        MeterFilter(BufferedTransformation *attachment=NULL, bool transparent=true)
                : m_transparent(transparent) {Detach(attachment); ResetMeter();}

        void SetTransparent(bool transparent) {m_transparent = transparent;}
        void AddRangeToSkip(unsigned int message, lword position, lword size, bool sortNow = true);
        void ResetMeter();
        void IsolatedInitialize(const NameValuePairs &parameters) {ResetMeter();}

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

        byte * CreatePutSpace(size_t &size)
                {return AttachedTransformation()->CreatePutSpace(size);}
        size_t Put2(const byte *begin, 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 CRYPTOPP_DLL TransparentFilter : public MeterFilter
{
public:
        TransparentFilter(BufferedTransformation *attachment=NULL) : MeterFilter(attachment, true) {}
};

//! _
class CRYPTOPP_DLL OpaqueFilter : public MeterFilter
{
public:
        OpaqueFilter(BufferedTransformation *attachment=NULL) : MeterFilter(attachment, false) {}
};

/*! FilterWithBufferedInput divides up 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. blockSize == 1).
*/
class CRYPTOPP_DLL FilterWithBufferedInput : public Filter
{
public:
        FilterWithBufferedInput(BufferedTransformation *attachment);
        //! firstSize and lastSize may be 0, 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);
        }
        /*! calls ForceNextPut() if hardFlush is true */
        bool IsolatedFlush(bool hardFlush, bool blocking);

        /*! The input buffer may contain more than blockSize bytes if lastSize != 0.
                ForceNextPut() forces a call to NextPut() if this is the case.
        */
        void ForceNextPut();

protected:
        bool DidFirstPut() {return m_firstInputDone;}

        virtual void InitializeDerivedAndReturnNewSizes(const NameValuePairs &parameters, size_t &firstSize, size_t &blockSize, size_t &lastSize)
                {InitializeDerived(parameters);}
        virtual void InitializeDerived(const NameValuePairs &parameters) {}
        // FirstPut() is called if (firstSize != 0 and totalLength >= firstSize)
        // or (firstSize == 0 and (totalLength > 0 or a MessageEnd() is received))
        virtual void FirstPut(const byte *inString) =0;
        // NextPut() is called if totalLength >= firstSize+blockSize+lastSize
        virtual void NextPutSingle(const byte *inString) {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() {}

private:
        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) {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 CRYPTOPP_DLL FilterWithInputQueue : public Filter
{
public:
        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) {m_inQueue.Clear();}

        ByteQueue m_inQueue;
};

//! Filter Wrapper for StreamTransformation
class CRYPTOPP_DLL StreamTransformationFilter : public FilterWithBufferedInput, private FilterPutSpaceHelper
{
public:
        enum BlockPaddingScheme {NO_PADDING, ZEROS_PADDING, PKCS_PADDING, ONE_AND_ZEROS_PADDING, DEFAULT_PADDING};
        /*! DEFAULT_PADDING means PKCS_PADDING if c.MandatoryBlockSize() > 1 && c.MinLastBlockSize() == 0 (e.g. ECB or CBC mode),
                otherwise NO_PADDING (OFB, CFB, CTR, CBC-CTS modes) */
        StreamTransformationFilter(StreamTransformation &c, BufferedTransformation *attachment = NULL, BlockPaddingScheme padding = DEFAULT_PADDING);

        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);
//      byte * CreatePutSpace(size_t &size);

protected:
        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

//! Filter Wrapper for HashTransformation
class CRYPTOPP_DLL HashFilter : public Bufferless<Filter>, private FilterPutSpaceHelper
{
public:
        HashFilter(HashTransformation &hm, BufferedTransformation *attachment = NULL, bool putMessage=false, int truncatedDigestSize=-1)
                : m_hashModule(hm), m_putMessage(putMessage), m_truncatedDigestSize(truncatedDigestSize) {Detach(attachment);}

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

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

        byte * CreatePutSpace(size_t &size) {return m_hashModule.CreateUpdateSpace(size);}

private:
        HashTransformation &m_hashModule;
        bool m_putMessage;
        int m_truncatedDigestSize;
        byte *m_space;
        unsigned int m_digestSize;
};

//! Filter Wrapper for HashTransformation
class CRYPTOPP_DLL HashVerificationFilter : public FilterWithBufferedInput
{
public:
        class HashVerificationFailed : public Exception
        {
        public:
                HashVerificationFailed()
                        : Exception(DATA_INTEGRITY_CHECK_FAILED, "HashVerifier: message hash not valid") {}
        };

        enum Flags {HASH_AT_BEGIN=1, PUT_MESSAGE=2, PUT_HASH=4, PUT_RESULT=8, THROW_EXCEPTION=16, DEFAULT_FLAGS = HASH_AT_BEGIN | PUT_RESULT};
        HashVerificationFilter(HashTransformation &hm, BufferedTransformation *attachment = NULL, word32 flags = DEFAULT_FLAGS);

        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:
        static inline unsigned int FirstSize(word32 flags, HashTransformation &hm) {return flags & HASH_AT_BEGIN ? hm.DigestSize() : 0;}
        static inline unsigned int LastSize(word32 flags, HashTransformation &hm) {return flags & HASH_AT_BEGIN ? 0 : hm.DigestSize();}

        HashTransformation &m_hashModule;
        word32 m_flags;
        SecByteBlock m_expectedHash;
        bool m_verified;
};

typedef HashVerificationFilter HashVerifier;    // for backwards compatibility

//! Filter Wrapper for PK_Signer
class CRYPTOPP_DLL SignerFilter : public Unflushable<Filter>
{
public:
        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 *begin, 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;
};

//! Filter Wrapper for PK_Verifier
class CRYPTOPP_DLL SignatureVerificationFilter : public FilterWithBufferedInput
{
public:
        class SignatureVerificationFailed : public Exception
        {
        public:
                SignatureVerificationFailed()
                        : Exception(DATA_INTEGRITY_CHECK_FAILED, "VerifierFilter: digital signature not valid") {}
        };

        enum Flags {SIGNATURE_AT_BEGIN=1, PUT_MESSAGE=2, PUT_SIGNATURE=4, PUT_RESULT=8, THROW_EXCEPTION=16, DEFAULT_FLAGS = SIGNATURE_AT_BEGIN | PUT_RESULT};
        SignatureVerificationFilter(const PK_Verifier &verifier, BufferedTransformation *attachment = NULL, word32 flags = DEFAULT_FLAGS);

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

//! Redirect input to another BufferedTransformation without owning it
class CRYPTOPP_DLL Redirector : public CustomSignalPropagation<Sink>
{
public:
        enum Behavior
        {
                DATA_ONLY = 0x00,
                PASS_SIGNALS = 0x01,
                PASS_WAIT_OBJECTS = 0x02,
                PASS_EVERYTHING = PASS_SIGNALS | PASS_WAIT_OBJECTS
        };

        Redirector() : m_target(NULL), m_behavior(PASS_EVERYTHING) {}
        Redirector(BufferedTransformation &target, Behavior behavior=PASS_EVERYTHING)
                : m_target(&target), m_behavior(behavior) {}

        void Redirect(BufferedTransformation &target) {m_target = &target;}
        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)
                {return m_target ? m_target->CreatePutSpace(size) : (byte *)(size=0, NULL);}
        size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking)
                {return m_target ? m_target->Put2(begin, 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)
                {return m_target ? m_target->ChannelCreatePutSpace(channel, size) : (byte *)(size=0, 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 *begin, size_t length, int messageEnd, bool blocking)
                {return m_owner.AttachedTransformation()->Put2(begin, 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;}

        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;
};

//! Base class for Filter classes that are proxies for a chain of other filters.
class CRYPTOPP_DLL ProxyFilter : public FilterWithBufferedInput
{
public:
        ProxyFilter(BufferedTransformation *filter, size_t firstSize, size_t lastSize, BufferedTransformation *attachment);

        bool IsolatedFlush(bool hardFlush, bool blocking);

        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;
};

//! simple proxy filter that doesn't modify the underlying filter's input or output
class CRYPTOPP_DLL SimpleProxyFilter : public ProxyFilter
{
public:
        SimpleProxyFilter(BufferedTransformation *filter, BufferedTransformation *attachment)
                : ProxyFilter(filter, 0, 0, attachment) {}

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

//! proxy for the filter created by PK_Encryptor::CreateEncryptionFilter
/*! This class is here just to provide symmetry with VerifierFilter. */
class CRYPTOPP_DLL PK_EncryptorFilter : public SimpleProxyFilter
{
public:
        PK_EncryptorFilter(RandomNumberGenerator &rng, const PK_Encryptor &encryptor, BufferedTransformation *attachment = NULL)
                : SimpleProxyFilter(encryptor.CreateEncryptionFilter(rng), attachment) {}
};

//! proxy for the filter created by PK_Decryptor::CreateDecryptionFilter
/*! This class is here just to provide symmetry with SignerFilter. */
class CRYPTOPP_DLL PK_DecryptorFilter : public SimpleProxyFilter
{
public:
        PK_DecryptorFilter(RandomNumberGenerator &rng, const PK_Decryptor &decryptor, BufferedTransformation *attachment = NULL)
                : SimpleProxyFilter(decryptor.CreateDecryptionFilter(rng), attachment) {}
};

//! Append input to a string object
template <class T>
class StringSinkTemplate : public Bufferless<Sink>
{
public:
        // VC60 workaround: no T::char_type
        typedef typename T::traits_type::char_type char_type;

        StringSinkTemplate(T &output)
                : m_output(&output) {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 *begin, size_t length, int messageEnd, bool 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 *)begin, (const char_type *)begin+length);
                }
                return 0;
        }

private:        
        T *m_output;
};

//! Append input to an std::string
CRYPTOPP_DLL_TEMPLATE_CLASS StringSinkTemplate<std::string>;
typedef StringSinkTemplate<std::string> StringSink;

//! Copy input to a memory buffer
class CRYPTOPP_DLL ArraySink : public Bufferless<Sink>
{
public:
        ArraySink(const NameValuePairs &parameters = g_nullNameValuePairs) {IsolatedInitialize(parameters);}
        ArraySink(byte *buf, size_t size) : m_buf(buf), m_size(size), m_total(0) {}

        size_t AvailableSize() {return SaturatingSubtract(m_size, m_total);}
        lword TotalPutLength() {return m_total;}

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

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

//! Xor input to a memory buffer
class CRYPTOPP_DLL ArrayXorSink : public ArraySink
{
public:
        ArrayXorSink(byte *buf, size_t size)
                : ArraySink(buf, size) {}

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

//! string-based implementation of Store interface
class StringStore : public Store
{
public:
        StringStore(const char *string = NULL)
                {StoreInitialize(MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}
        StringStore(const byte *string, size_t length)
                {StoreInitialize(MakeParameters("InputBuffer", ConstByteArrayParameter(string, length)));}
        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=NULL_CHANNEL, bool blocking=true);
        CRYPTOPP_DLL size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=NULL_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=NULL_CHANNEL, bool blocking=true);
        size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=NULL_CHANNEL, bool blocking=true) const
        {
                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) {}
        lword MaxRetrievable() const {return m_size;}
        size_t TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel=NULL_CHANNEL, bool blocking=true);
        size_t CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end=LWORD_MAX, const std::string &channel=NULL_CHANNEL, bool blocking=true) const;

private:
        lword m_size;
};

//! A Filter that pumps data into its attachment as input
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Source : public InputRejecting<Filter>
{
public:
        Source(BufferedTransformation *attachment = NULL)
                {Source::Detach(attachment);}

        lword Pump(lword pumpMax=size_t(0)-1)
                {Pump2(pumpMax); return pumpMax;}
        unsigned int PumpMessages(unsigned int count=UINT_MAX)
                {PumpMessages2(count); return count;}
        void PumpAll()
                {PumpAll2();}
        virtual size_t Pump2(lword &byteCount, bool blocking=true) =0;
        virtual size_t PumpMessages2(unsigned int &messageCount, bool blocking=true) =0;
        virtual size_t PumpAll2(bool blocking=true);
        virtual bool SourceExhausted() const =0;

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

//! Turn a Store into a Source
template <class T>
class SourceTemplate : public Source
{
public:
        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, NULL_CHANNEL, blocking);}
        size_t PumpMessages2(unsigned int &messageCount, bool blocking=true)
                {return m_store.TransferMessagesTo2(*AttachedTransformation(), messageCount, NULL_CHANNEL, blocking);}
        size_t PumpAll2(bool blocking=true)
                {return m_store.TransferAllTo2(*AttachedTransformation(), NULL_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;
};

//! string-based implementation of Source interface
class CRYPTOPP_DLL StringSource : public SourceTemplate<StringStore>
{
public:
        StringSource(BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {}
        StringSource(const char *string, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {SourceInitialize(pumpAll, MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}
        StringSource(const byte *string, size_t length, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {SourceInitialize(pumpAll, MakeParameters("InputBuffer", ConstByteArrayParameter(string, length)));}
        StringSource(const std::string &string, bool pumpAll, BufferedTransformation *attachment = NULL)
                : SourceTemplate<StringStore>(attachment) {SourceInitialize(pumpAll, MakeParameters("InputBuffer", ConstByteArrayParameter(string)));}
};

//! 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

#endif

---