mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-29 02:52:13 +00:00
110 lines
2.2 KiB
C++
110 lines
2.2 KiB
C++
//
|
|
// 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
|