Botan 2.19.2
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/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 {
27 const uint16_t result = (tst != 0);
28 return ~(result - 1);
29 }
30
31inline gf2m gray_to_lex(gf2m gray)
32 {
33 gf2m result = gray ^ (gray >> 8);
34 result ^= (result >> 4);
35 result ^= (result >> 2);
36 result ^= (result >> 1);
37 return result;
38 }
39
41 {
42 return (lex >> 1) ^ lex;
43 }
44
45inline size_t bit_size_to_byte_size(size_t bit_size)
46 {
47 return (bit_size - 1) / 8 + 1;
48 }
49
50inline size_t bit_size_to_32bit_size(size_t bit_size)
51 {
52 return (bit_size - 1) / 32 + 1;
53 }
54
55}
56
57#endif
fe T
Definition: ge.cpp:37
Definition: alg_id.cpp:13
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
Definition: gf2m_small_m.h:22