1//
2// Checksum64.h
3//
4// Library: Foundation
5// Package: Core
6// Module: Checksum64
7//
8// Definition of the Checksum64 class.
9//
10// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
11// and Contributors.
12//
13// SPDX-License-Identifier: BSL-1.0
14//
15
16
17#ifndef Foundation_Checksum64_INCLUDED
18#define Foundation_Checksum64_INCLUDED
19
20
21#include "Poco/Foundation.h"
22#include "Poco/ChecksumImpl.h"
23
24
25namespace Poco {
26
27
28class Foundation_API Checksum64 : public ChecksumImpl
29 /// This class calculates CRC-64 checksums for arbitrary data.
30 ///
31 /// The algorithm and table are based on the polynomial
32 ///
33 /// x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 +
34 /// x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 +
35 /// x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
36 /// x^7 + x^4 + x + 1
37 ///
38 /// Implementation is adapted from the DLT1 spec:
39 /// ECMA - 182, http://www.ecma-international.org/publications/standards/Ecma-182.htm
40 ///
41{
42public:
43 Checksum64();
44 /// Creates a CRC-64 checksum initialized to 0.
45
46 Checksum64(Type t);
47 /// Creates the Checksum64, using the given type.
48
49 ~Checksum64();
50 /// Destroys the Checksum64.
51
52 void update(const char* data, unsigned length);
53 /// Updates the checksum with the given data.
54
55 void update(const std::string& data);
56 /// Updates the checksum with the given data.
57
58 void update(char data);
59 /// Updates the checksum with the given data.
60
61 Poco::UInt64 checksum() const;
62 /// Returns the calculated checksum.
63
64 ChecksumImpl::Type type() const;
65 /// Which type of checksum are we calculating.
66
67private:
68 static Poco::UInt64 _initCRC64Val;
69 static Poco::UInt64 _finXORVal;
70 static const unsigned _tableSize = 256;
71 static Poco::UInt64 _crcTable[_tableSize];
72 Poco::UInt64 _value;
73};
74
75
76//
77// inlines
78//
79inline void Checksum64::update(const std::string& data)
80{
81 update(data.c_str(), static_cast<unsigned int>(data.size()));
82}
83
84
85inline void Checksum64::update(char c)
86{
87 update(&c, 1);
88}
89
90
91inline Poco::UInt64 Checksum64::checksum() const
92{
93 return _value;
94}
95
96
97inline ChecksumImpl::Type Checksum64::type() const
98{
99 return TYPE_CRC64_IMPL;
100}
101
102
103} // namespace Poco
104
105
106#endif // Foundation_Checksum64_INCLUDED
107