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