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/**
* (C) Copyright Projet SECRET, INRIA, Rocquencourt
* (C) Bhaskar Biswas and Nicolas Sendrier
*
* (C) 2014 cryptosource GmbH
* (C) 2014 Falko Strenzke fstrenzke@cryptosource.de
*
* Distributed under the terms of the Botan license
*
*/
#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>
u16bit expand_mask_16bit(T tst)
{
const u16bit result = (tst != 0);
return ~(result - 1);
}
inline gf2m_small_m::gf2m gray_to_lex(gf2m_small_m::gf2m gray)
{
gf2m_small_m::gf2m result = gray ^ (gray>>8);
result ^= (result >> 4);
result ^= (result >> 2);
result ^= (result >> 1);
return result;
}
inline gf2m_small_m::gf2m lex_to_gray(gf2m_small_m::gf2m lex)
{
return (lex>>1) ^ lex;
}
inline u32bit bit_size_to_byte_size(u32bit bit_size)
{
return (bit_size - 1) / 8 + 1;
}
inline u32bit bit_size_to_32bit_size(u32bit bit_size)
{
return (bit_size - 1) / 32 + 1;
}
}
#endif
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