1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
// file : libbutl/sha256.hxx -*- C++ -*-
// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef LIBBUTL_SHA256_HXX
#define LIBBUTL_SHA256_HXX
#include <string>
#include <cstring> // strlen(), memcpy()
#include <cstdint>
#include <cstddef> // size_t
#include <type_traits> // enable_if, is_integral
#include <libbutl/export.hxx>
namespace butl
{
// SHA256 checksum calculator.
//
// For a single chunk of data a sum can be obtained in one line, for
// example:
//
// cerr << sha256 ("123").string () << endl;
//
class LIBBUTL_SYMEXPORT sha256
{
public:
sha256 ();
// Append binary data.
//
void
append (const void*, std::size_t);
sha256 (const void* b, std::size_t n): sha256 () {append (b, n);}
// Append string.
//
// Note that the hash includes the '\0' terminator. Failed that, a call
// with an empty string will be indistinguishable from no call at all.
//
void
append (const std::string& s) {append (s.c_str (), s.size () + 1);}
void
append (const char* s) {append (s, std::strlen (s) + 1);}
explicit
sha256 (const std::string& s): sha256 () {append (s);}
explicit
sha256 (const char* s): sha256 () {append (s);}
// Append an integral type with a fast path optimization (see
// SHA256_Update() for details).
//
void
append (char c)
{
std::uint32_t r ((ctx_.count >> 3) & 0x3f);
if (1 < 64 - r)
{
ctx_.buf[r] = static_cast<std::uint8_t> (c);
ctx_.count += 8;
}
else
append (&c, 1);
}
template <typename T>
typename std::enable_if<std::is_integral<T>::value>::type
append (T x)
{
const std::size_t len (sizeof (x));
std::uint32_t r ((ctx_.count >> 3) & 0x3f);
if (len < 64 - r)
{
std::memcpy (&ctx_.buf[r], &x, sizeof (x));
ctx_.count += len << 3;
}
else
append (&x, len);
}
// Extract result.
//
// It can be obtained as either a 32-byte binary digest or as a 64-
// character hex-encoded C-string.
//
using digest_type = std::uint8_t[32];
const digest_type&
binary () const;
const char*
string () const;
public:
struct context
{
std::uint32_t state[8];
std::uint64_t count;
std::uint8_t buf[64];
};
private:
union
{
mutable context ctx_;
mutable char str_[65];
};
mutable digest_type bin_;
mutable bool done_;
};
// Convert a SHA256 string representation (64 hex digits) to the fingerprint
// canonical representation (32 colon-separated upper case hex digit pairs,
// like 01:AB:CD:...). Throw invalid_argument if the argument is not a valid
// SHA256 string.
//
LIBBUTL_SYMEXPORT std::string
sha256_to_fingerprint (const std::string&);
// Convert a fingerprint (32 colon-separated hex digit pairs) to the SHA256
// string representation (64 lower case hex digits). Throw invalid_argument
// if the argument is not a valid fingerprint.
//
LIBBUTL_SYMEXPORT std::string
fingerprint_to_sha256 (const std::string&);
}
#endif // LIBBUTL_SHA256_HXX
|
