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111 lines
2.2 KiB
C++
111 lines
2.2 KiB
C++
//
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// Checksum.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/Checksum.h#1 $
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//
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// Library: Foundation
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// Package: Core
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// Module: Checksum
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//
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// Definition of the Checksum class.
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//
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// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_Checksum_INCLUDED
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#define Foundation_Checksum_INCLUDED
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#include "Poco/Foundation.h"
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namespace Poco {
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class Foundation_API Checksum
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/// This class calculates CRC-32 or Adler-32 checksums
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/// for arbitrary data.
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///
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/// A cyclic redundancy check (CRC) is a type of hash function, which is used to produce a
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/// small, fixed-size checksum of a larger block of data, such as a packet of network
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/// traffic or a computer file. CRC-32 is one of the most commonly used CRC algorithms.
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///
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/// Adler-32 is a checksum algorithm which was invented by Mark Adler.
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/// It is almost as reliable as a 32-bit cyclic redundancy check for protecting against
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/// accidental modification of data, such as distortions occurring during a transmission,
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/// but is significantly faster to calculate in software.
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{
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public:
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enum Type
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{
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TYPE_ADLER32 = 0,
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TYPE_CRC32
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};
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Checksum();
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/// Creates a CRC-32 checksum initialized to 0.
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Checksum(Type t);
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/// Creates the Checksum, using the given type.
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~Checksum();
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/// Destroys the Checksum.
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void update(const char* data, unsigned length);
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/// Updates the checksum with the given data.
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void update(const std::string& data);
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/// Updates the checksum with the given data.
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void update(char data);
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/// Updates the checksum with the given data.
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Poco::UInt32 checksum() const;
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/// Returns the calculated checksum.
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Type type() const;
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/// Which type of checksum are we calulcating
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private:
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Type _type;
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Poco::UInt32 _value;
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};
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//
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// inlines
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//
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inline void Checksum::update(const std::string& data)
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{
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update(data.c_str(), static_cast<unsigned int>(data.size()));
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}
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inline void Checksum::update(char c)
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{
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update(&c, 1);
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}
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inline Poco::UInt32 Checksum::checksum() const
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{
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return _value;
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}
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inline Checksum::Type Checksum::type() const
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{
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return _type;
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}
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} // namespace Poco
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#endif // Foundation_Checksum_INCLUDED
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