From bf22c4575bae3bc158e3070bd0dae9aab40bfde3 Mon Sep 17 00:00:00 2001
From: Jeffrey Walton <noloader@gmail.com>
Date: Sun, 24 Apr 2016 13:24:45 -0400
Subject: Add CRC-32C using CXX and SSE4 (Issue 160)

---
 crc.h | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

(limited to 'crc.h')

diff --git a/crc.h b/crc.h
index d31555dd..89b68629 100644
--- a/crc.h
+++ b/crc.h
@@ -2,7 +2,7 @@
 
 //! \file
 //! \headerfile crc.h
-//! \brief Classes for CRC-32 checksum algorithm
+//! \brief Classes for CRC-32 and CRC-32C checksum algorithm
 
 #ifndef CRYPTOPP_CRC32_H
 #define CRYPTOPP_CRC32_H
@@ -21,7 +21,8 @@ const word32 CRC32_NEGL = 0xffffffffL;
 #define CRC32_SHIFTED(c) (c << 8)
 #endif
 
-//! CRC Checksum Calculation
+//! \brief CRC-32 Checksum Calculation
+//! \details Uses CRC polynomial 0xEDB88320
 class CRC32 : public HashTransformation
 {
 public:
@@ -36,9 +37,34 @@ public:
 	void UpdateByte(byte b) {m_crc = m_tab[CRC32_INDEX(m_crc) ^ b] ^ CRC32_SHIFTED(m_crc);}
 	byte GetCrcByte(size_t i) const {return ((byte *)&(m_crc))[i];}
 
+protected:
+	void Reset() {m_crc = CRC32_NEGL;}
+
 private:
+	static const word32 m_tab[256];
+	word32 m_crc;
+};
+
+//! \brief CRC-32C Checksum Calculation
+//! \details Uses CRC polynomial 0x82F63B78
+class CRC32C : public HashTransformation
+{
+public:
+	CRYPTOPP_CONSTANT(DIGESTSIZE = 4)
+	CRC32C();
+	void Update(const byte *input, size_t length);
+	void TruncatedFinal(byte *hash, size_t size);
+	unsigned int DigestSize() const {return DIGESTSIZE;}
+    static const char * StaticAlgorithmName() {return "CRC32C";}
+    std::string AlgorithmName() const {return StaticAlgorithmName();}
+
+	void UpdateByte(byte b) {m_crc = m_tab[CRC32_INDEX(m_crc) ^ b] ^ CRC32_SHIFTED(m_crc);}
+	byte GetCrcByte(size_t i) const {return ((byte *)&(m_crc))[i];}
+
+protected:
 	void Reset() {m_crc = CRC32_NEGL;}
-	
+
+private:
 	static const word32 m_tab[256];
 	word32 m_crc;
 };
-- 
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