From b21162cf8e06f40baa1f58be6a8c17435cebc34d Mon Sep 17 00:00:00 2001
From: weidai <weidai@57ff6487-cd31-0410-9ec3-f628ee90f5f0>
Date: Fri, 4 Oct 2002 17:31:41 +0000
Subject: Initial revision

git-svn-id: svn://svn.code.sf.net/p/cryptopp/code/trunk/c5@2 57ff6487-cd31-0410-9ec3-f628ee90f5f0
---
 iterhash.h | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 iterhash.h

(limited to 'iterhash.h')

diff --git a/iterhash.h b/iterhash.h
new file mode 100644
index 0000000..1ae9b15
--- /dev/null
+++ b/iterhash.h
@@ -0,0 +1,120 @@
+#ifndef CRYPTOPP_ITERHASH_H
+#define CRYPTOPP_ITERHASH_H
+
+#include "cryptlib.h"
+#include "secblock.h"
+#include "misc.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+template <class T, class BASE>
+class IteratedHashBase : public BASE
+{
+public:
+	typedef T HashWordType;
+
+	IteratedHashBase(unsigned int blockSize, unsigned int digestSize);
+	unsigned int DigestSize() const {return m_digest.size() * sizeof(T);};
+	unsigned int OptimalBlockSize() const {return BlockSize();}
+	void Update(const byte *input, unsigned int length);
+	byte * CreateUpdateSpace(unsigned int &size);
+	void Restart();
+
+protected:
+	T GetBitCountHi() const {return (m_countLo >> (8*sizeof(T)-3)) + (m_countHi << 3);}
+	T GetBitCountLo() const {return m_countLo << 3;}
+
+	virtual unsigned int HashMultipleBlocks(const T *input, unsigned int length);
+	void PadLastBlock(unsigned int lastBlockSize, byte padFirst=0x80);
+	virtual void Init() =0;
+	virtual void HashBlock(const T *input) =0;
+	virtual unsigned int BlockSize() const =0;
+
+	SecBlock<T> m_data;			// Data buffer
+	SecBlock<T> m_digest;		// Message digest
+
+private:
+	T m_countLo, m_countHi;
+};
+
+//! .
+template <class T, class B, class BASE>
+class IteratedHashBase2 : public IteratedHashBase<T, BASE>
+{
+public:
+	IteratedHashBase2(unsigned int blockSize, unsigned int digestSize)
+		: IteratedHashBase<T, BASE>(blockSize, digestSize) {}
+
+	typedef B ByteOrderClass;
+	typedef typename IteratedHashBase<T, BASE>::HashWordType HashWordType;
+
+	inline static void CorrectEndianess(HashWordType *out, const HashWordType *in, unsigned int byteCount)
+	{
+		ConditionalByteReverse(B::ToEnum(), out, in, byteCount);
+	}
+
+	void TruncatedFinal(byte *hash, unsigned int size);
+
+protected:
+	void HashBlock(const HashWordType *input);
+
+	virtual void vTransform(const HashWordType *data) =0;
+};
+
+//! .
+template <class T, class B, unsigned int S, class BASE = HashTransformation>
+class IteratedHash : public IteratedHashBase2<T, B, BASE>
+{
+public:
+	enum {BLOCKSIZE = S};
+
+private:
+	CRYPTOPP_COMPILE_ASSERT((BLOCKSIZE & (BLOCKSIZE - 1)) == 0);		// blockSize is a power of 2
+
+protected:
+	IteratedHash(unsigned int digestSize) : IteratedHashBase2<T, B, BASE>(BLOCKSIZE, digestSize) {}
+	unsigned int BlockSize() const {return BLOCKSIZE;}
+};
+
+template <class T, class B, unsigned int S, class M>
+class IteratedHashWithStaticTransform : public IteratedHash<T, B, S>
+{
+protected:
+	IteratedHashWithStaticTransform(unsigned int digestSize) : IteratedHash<T, B, S>(digestSize) {}
+	void vTransform(const T *data) {M::Transform(m_digest, data);}
+	std::string AlgorithmName() const {return M::StaticAlgorithmName();}
+};
+
+// *************************************************************
+
+template <class T, class B, class BASE> void IteratedHashBase2<T, B, BASE>::TruncatedFinal(byte *hash, unsigned int size)
+{
+	ThrowIfInvalidTruncatedSize(size);
+
+	PadLastBlock(BlockSize() - 2*sizeof(HashWordType));
+	CorrectEndianess(m_data, m_data, BlockSize() - 2*sizeof(HashWordType));
+
+	m_data[m_data.size()-2] = B::ToEnum() ? GetBitCountHi() : GetBitCountLo();
+	m_data[m_data.size()-1] = B::ToEnum() ? GetBitCountLo() : GetBitCountHi();
+
+	vTransform(m_data);
+	CorrectEndianess(m_digest, m_digest, DigestSize());
+	memcpy(hash, m_digest, size);
+
+	Restart();		// reinit for next use
+}
+
+template <class T, class B, class BASE> void IteratedHashBase2<T, B, BASE>::HashBlock(const HashWordType *input)
+{
+	if (NativeByteOrderIs(B::ToEnum()))
+		vTransform(input);
+	else
+	{
+		ByteReverse(m_data.begin(), input, BlockSize());
+		vTransform(m_data);
+	}
+}
+
+NAMESPACE_END
+
+#endif
-- 
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