/src/botan/build/include/botan/hash.h
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1 | | /* |
2 | | * Hash Function Base Class |
3 | | * (C) 1999-2008 Jack Lloyd |
4 | | * |
5 | | * Botan is released under the Simplified BSD License (see license.txt) |
6 | | */ |
7 | | |
8 | | #ifndef BOTAN_HASH_FUNCTION_BASE_CLASS_H_ |
9 | | #define BOTAN_HASH_FUNCTION_BASE_CLASS_H_ |
10 | | |
11 | | #include <botan/buf_comp.h> |
12 | | #include <string> |
13 | | #include <memory> |
14 | | |
15 | | namespace Botan { |
16 | | |
17 | | /** |
18 | | * This class represents hash function (message digest) objects |
19 | | */ |
20 | | class BOTAN_PUBLIC_API(2,0) HashFunction : public Buffered_Computation |
21 | | { |
22 | | public: |
23 | | /** |
24 | | * Create an instance based on a name, or return null if the |
25 | | * algo/provider combination cannot be found. If provider is |
26 | | * empty then best available is chosen. |
27 | | */ |
28 | | static std::unique_ptr<HashFunction> |
29 | | create(const std::string& algo_spec, |
30 | | const std::string& provider = ""); |
31 | | |
32 | | /** |
33 | | * Create an instance based on a name |
34 | | * If provider is empty then best available is chosen. |
35 | | * @param algo_spec algorithm name |
36 | | * @param provider provider implementation to use |
37 | | * Throws Lookup_Error if not found. |
38 | | */ |
39 | | static std::unique_ptr<HashFunction> |
40 | | create_or_throw(const std::string& algo_spec, |
41 | | const std::string& provider = ""); |
42 | | |
43 | | /** |
44 | | * @return list of available providers for this algorithm, empty if not available |
45 | | * @param algo_spec algorithm name |
46 | | */ |
47 | | static std::vector<std::string> providers(const std::string& algo_spec); |
48 | | |
49 | | /** |
50 | | * @return new object representing the same algorithm as *this |
51 | | */ |
52 | | virtual HashFunction* clone() const = 0; |
53 | | |
54 | | /** |
55 | | * @return provider information about this implementation. Default is "base", |
56 | | * might also return "sse2", "avx2", "openssl", or some other arbitrary string. |
57 | | */ |
58 | 0 | virtual std::string provider() const { return "base"; } |
59 | | |
60 | | virtual ~HashFunction() = default; |
61 | | |
62 | | /** |
63 | | * Reset the state. |
64 | | */ |
65 | | virtual void clear() = 0; |
66 | | |
67 | | /** |
68 | | * @return the hash function name |
69 | | */ |
70 | | virtual std::string name() const = 0; |
71 | | |
72 | | /** |
73 | | * @return hash block size as defined for this algorithm |
74 | | */ |
75 | 0 | virtual size_t hash_block_size() const { return 0; } |
76 | | |
77 | | /** |
78 | | * Return a new hash object with the same state as *this. This |
79 | | * allows computing the hash of several messages with a common |
80 | | * prefix more efficiently than would otherwise be possible. |
81 | | * |
82 | | * This function should be called `clone` but that was already |
83 | | * used for the case of returning an uninitialized object. |
84 | | * @return new hash object |
85 | | */ |
86 | | virtual std::unique_ptr<HashFunction> copy_state() const = 0; |
87 | | }; |
88 | | |
89 | | } |
90 | | |
91 | | #endif |