First commit

src/Nazara/Core/Hash/Fletcher16.cpp

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+// Copyright (C) 2012 Jérôme Leclercq
+// This file is part of the "Nazara Engine".
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Core/Hash/Fletcher16.hpp>
+#include <Nazara/Core/Endianness.hpp>
+#include <Nazara/Core/Debug.hpp>
+
+struct NzHashFletcher16_state
+{
+	nzUInt16 sum1;
+	nzUInt16 sum2;
+};
+
+NzHashFletcher16::NzHashFletcher16()
+{
+	m_state = new NzHashFletcher16_state;
+}
+
+NzHashFletcher16::~NzHashFletcher16()
+{
+	delete m_state;
+}
+
+void NzHashFletcher16::Append(const nzUInt8* data, unsigned int len)
+{
+	while (len)
+	{
+		unsigned int tlen = std::min(len, 21U);
+		len -= tlen;
+		do
+		{
+			m_state->sum1 += *data++;
+			m_state->sum2 += m_state->sum1;
+		}
+		while (--tlen);
+
+		m_state->sum1 = (m_state->sum1 & 0xff) + (m_state->sum1 >> 8);
+		m_state->sum2 = (m_state->sum2 & 0xff) + (m_state->sum2 >> 8);
+	}
+}
+
+void NzHashFletcher16::Begin()
+{
+	m_state->sum1 = 0xff;
+	m_state->sum2 = 0xff;
+}
+
+NzHashDigest NzHashFletcher16::End()
+{
+	m_state->sum1 = (m_state->sum1 & 0xff) + (m_state->sum1 >> 8);
+	m_state->sum2 = (m_state->sum2 & 0xff) + (m_state->sum2 >> 8);
+
+	nzUInt32 fletcher = (m_state->sum2 << 8) | m_state->sum1;
+	if (NazaraEndianness == nzEndianness_BigEndian)
+		NzByteSwap(&fletcher, sizeof(nzUInt32));
+
+	return NzHashDigest(GetHashName(), reinterpret_cast<nzUInt8*>(&fletcher), 2);
+}
+
+unsigned int NzHashFletcher16::GetDigestLength()
+{
+	return 2;
+}
+
+NzString NzHashFletcher16::GetHashName()
+{
+	static NzString hashName = "Fletcher16";
+	return hashName;
+}