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 | |
25 | namespace Poco { |
26 | |
27 | |
28 | class 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 | { |
42 | public: |
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 | |
67 | private: |
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 | // |
79 | inline void Checksum64::update(const std::string& data) |
80 | { |
81 | update(data.c_str(), static_cast<unsigned int>(data.size())); |
82 | } |
83 | |
84 | |
85 | inline void Checksum64::update(char c) |
86 | { |
87 | update(&c, 1); |
88 | } |
89 | |
90 | |
91 | inline Poco::UInt64 Checksum64::checksum() const |
92 | { |
93 | return _value; |
94 | } |
95 | |
96 | |
97 | inline 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 | |