topical media & game development
lib-of-vs-libs-Poco-include-Poco-Checksum.h / h
//
// Checksum.h
//
//
//
// Library: Foundation
// Package: Core
// Module: Checksum
//
// Definition of the Checksum class.
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
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
(C) Æliens
04/09/2009
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