iterhash.h

#ifndef CRYPTOPP_ITERHASH_H
#define CRYPTOPP_ITERHASH_H

#include "cryptlib.h"
#include "secblock.h"
#include "misc.h"
#include "simple.h"

NAMESPACE_BEGIN(CryptoPP)

//! exception thrown when trying to hash more data than is allowed by a hash function
class CRYPTOPP_DLL HashInputTooLong : public InvalidDataFormat
{
public:
        explicit HashInputTooLong(const std::string &alg)
                : InvalidDataFormat("IteratedHashBase: input data exceeds maximum allowed by hash function " + alg) {}
};

//! _
template <class T, class BASE>
class CRYPTOPP_NO_VTABLE IteratedHashBase : public BASE
{
public:
        typedef T HashWordType;

        IteratedHashBase() : m_countLo(0), m_countHi(0) {}
        unsigned int BlockSize() const {return (unsigned int)m_data.size() * sizeof(T);}
        unsigned int OptimalBlockSize() const {return BlockSize();}
        unsigned int OptimalDataAlignment() const {return sizeof(T);}
        void Update(const byte *input, size_t length);
        byte * CreateUpdateSpace(size_t &size);
        void Restart();
        void TruncatedFinal(byte *digest, size_t size);

protected:
        void SetBlockSize(unsigned int blockSize) {m_data.resize(blockSize / sizeof(HashWordType));}
        void SetStateSize(unsigned int stateSize) {m_digest.resize(stateSize / sizeof(HashWordType));}

        T GetBitCountHi() const {return (m_countLo >> (8*sizeof(T)-3)) + (m_countHi << 3);}
        T GetBitCountLo() const {return m_countLo << 3;}

        void PadLastBlock(unsigned int lastBlockSize, byte padFirst=0x80);
        virtual void Init() =0;

        virtual ByteOrder GetByteOrder() const =0;
        virtual void HashEndianCorrectedBlock(const HashWordType *data) =0;
        virtual size_t HashMultipleBlocks(const T *input, size_t length);
        void HashBlock(const HashWordType *input) {HashMultipleBlocks(input, BlockSize());}

        SecBlock<T> m_data;                     // Data buffer
        SecBlock<T> m_digest;           // Message digest

private:
        T m_countLo, m_countHi;
};

//! _
template <class T_HashWordType, class T_Endianness, unsigned int T_BlockSize, class T_Base = HashTransformation>
class CRYPTOPP_NO_VTABLE IteratedHash : public IteratedHashBase<T_HashWordType, T_Base>
{
public:
        typedef T_Endianness ByteOrderClass;
        typedef T_HashWordType HashWordType;

        CRYPTOPP_CONSTANT(BLOCKSIZE = T_BlockSize)
        // BCB2006 workaround: can't use BLOCKSIZE here
        CRYPTOPP_COMPILE_ASSERT((T_BlockSize & (T_BlockSize - 1)) == 0);        // blockSize is a power of 2

        ByteOrder GetByteOrder() const {return T_Endianness::ToEnum();}

        inline static void CorrectEndianess(HashWordType *out, const HashWordType *in, size_t byteCount)
        {
                ConditionalByteReverse(T_Endianness::ToEnum(), out, in, byteCount);
        }

protected:
        IteratedHash() {this->SetBlockSize(T_BlockSize);}
};

//! _
template <class T_HashWordType, class T_Endianness, unsigned int T_BlockSize, unsigned int T_StateSize, class T_Transform, unsigned int T_DigestSize = 0>
class CRYPTOPP_NO_VTABLE IteratedHashWithStaticTransform
        : public ClonableImpl<T_Transform, AlgorithmImpl<IteratedHash<T_HashWordType, T_Endianness, T_BlockSize>, T_Transform> >
{
public:
        CRYPTOPP_CONSTANT(DIGESTSIZE = T_DigestSize ? T_DigestSize : T_StateSize)
        unsigned int DigestSize() const {return DIGESTSIZE;};

protected:
        IteratedHashWithStaticTransform()
        {
                this->SetStateSize(T_StateSize);
                Init();
        }
        void HashEndianCorrectedBlock(const T_HashWordType *data) {T_Transform::Transform(this->m_digest, data);}
        void Init() {T_Transform::InitState(this->m_digest);}
};

NAMESPACE_END

#ifdef CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES
#include "iterhash.cpp"
#endif

NAMESPACE_BEGIN(CryptoPP)

#ifdef WORD64_AVAILABLE
CRYPTOPP_DLL_TEMPLATE_CLASS IteratedHashBase<word64, HashTransformation>;
CRYPTOPP_STATIC_TEMPLATE_CLASS IteratedHashBase<word64, MessageAuthenticationCode>;
#endif

CRYPTOPP_DLL_TEMPLATE_CLASS IteratedHashBase<word32, HashTransformation>;
CRYPTOPP_STATIC_TEMPLATE_CLASS IteratedHashBase<word32, MessageAuthenticationCode>;

NAMESPACE_END

#endif

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