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/*
* Copyright (C) 2020 Olivier Chéron <olivier.cheron@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef CRYPTONITE_HASH_PREFIX_H
#define CRYPTONITE_HASH_PREFIX_H
#include <stdint.h>
static inline uint32_t constant_time_msb(uint32_t a)
{
return 0 - (a >> 31);
}
static inline uint32_t constant_time_lt(uint32_t a, uint32_t b)
{
return constant_time_msb(a ^ ((a ^ b) | ((a - b) ^ b)));
}
static inline uint32_t constant_time_ge(uint32_t a, uint32_t b)
{
return ~constant_time_lt(a, b);
}
static inline uint32_t constant_time_is_zero(uint32_t a)
{
return constant_time_msb(~a & (a - 1));
}
static inline uint32_t constant_time_eq(uint32_t a, uint32_t b)
{
return constant_time_is_zero(a ^ b);
}
static inline uint64_t constant_time_msb_64(uint64_t a)
{
return 0 - (a >> 63);
}
static inline uint64_t constant_time_lt_64(uint64_t a, uint64_t b)
{
return constant_time_msb_64(a ^ ((a ^ b) | ((a - b) ^ b)));
}
#endif
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