Botan 3.5.0
Crypto and TLS for C&
code_based_util.h
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1/*
2 * (C) Copyright Projet SECRET, INRIA, Rocquencourt
3 * (C) Bhaskar Biswas and Nicolas Sendrier
4 *
5 * (C) 2014 cryptosource GmbH
6 * (C) 2014 Falko Strenzke fstrenzke@cryptosource.de
7 *
8 * Botan is released under the Simplified BSD License (see license.txt)
9 *
10 */
11
12#ifndef BOTAN_CODE_BASED_UTIL_H_
13#define BOTAN_CODE_BASED_UTIL_H_
14
15#include <botan/internal/gf2m_small_m.h>
16
17namespace Botan {
18
19/**
20* Expand an input to a bit mask depending on it being being zero or non-zero
21* @param tst the input
22* @return the mask 0xFFFF if tst is non-zero and 0 otherwise
23*/
24template <typename T>
25uint16_t expand_mask_16bit(T tst) {
26 const uint16_t result = (tst != 0);
27 return ~(result - 1);
28}
29
30inline gf2m gray_to_lex(gf2m gray) {
31 gf2m result = gray ^ (gray >> 8);
32 result ^= (result >> 4);
33 result ^= (result >> 2);
34 result ^= (result >> 1);
35 return result;
36}
37
38inline gf2m lex_to_gray(gf2m lex) {
39 return (lex >> 1) ^ lex;
40}
41
42inline size_t bit_size_to_byte_size(size_t bit_size) {
43 return (bit_size - 1) / 8 + 1;
44}
45
46inline size_t bit_size_to_32bit_size(size_t bit_size) {
47 return (bit_size - 1) / 32 + 1;
48}
49
50} // namespace Botan
51
52#endif
FE_25519 T
Definition ge.cpp:34
gf2m lex_to_gray(gf2m lex)
uint16_t expand_mask_16bit(T tst)
gf2m gray_to_lex(gf2m gray)
size_t bit_size_to_32bit_size(size_t bit_size)
size_t bit_size_to_byte_size(size_t bit_size)
uint16_t gf2m