blob: 5b0a9195a0909dc213c360246fa88c83ed7dc4d8 (
plain)
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
|
/*
* (C) Copyright Projet SECRET, INRIA, Rocquencourt
* (C) Bhaskar Biswas and Nicolas Sendrier
*
* (C) 2014 cryptosource GmbH
* (C) 2014 Falko Strenzke fstrenzke@cryptosource.de
*
* Botan is released under the Simplified BSD License (see license.txt)
*
*/
#ifndef BOTAN_CODE_BASED_UTIL_H_
#define BOTAN_CODE_BASED_UTIL_H_
#include <botan/gf2m_small_m.h>
namespace Botan {
/**
* Expand an input to a bit mask depending on it being being zero or non-zero
* @param tst the input
* @return the mask 0xFFFF if tst is non-zero and 0 otherwise
*/
template<typename T>
uint16_t expand_mask_16bit(T tst)
{
const uint16_t result = (tst != 0);
return ~(result - 1);
}
inline gf2m gray_to_lex(gf2m gray)
{
gf2m result = gray ^ (gray >> 8);
result ^= (result >> 4);
result ^= (result >> 2);
result ^= (result >> 1);
return result;
}
inline gf2m lex_to_gray(gf2m lex)
{
return (lex >> 1) ^ lex;
}
inline size_t bit_size_to_byte_size(size_t bit_size)
{
return (bit_size - 1) / 8 + 1;
}
inline size_t bit_size_to_32bit_size(size_t bit_size)
{
return (bit_size - 1) / 32 + 1;
}
}
#endif
|