generic-ops.h

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// Copyright (c) 2014-2022, The Monero Project
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// permitted provided that the following conditions are met:
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// 1. Redistributions of source code must retain the above copyright notice, this list of
//    conditions and the following disclaimer.
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// 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
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
//    used to endorse or promote products derived from this software without specific
//    prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
 
#pragma once
 
#include <cstddef>
#include <cstring>
#include <cstdint>
#include <functional>
#include <memory>
#include <sodium/crypto_verify_32.h>
#include <sodium/crypto_shorthash_siphash24.h>
 
#include "random.h"
 
#define CRYPTO_MAKE_COMPARABLE(type) \
namespace crypto { \
  inline bool operator==(const type &_v1, const type &_v2) { \
    return !memcmp(&_v1, &_v2, sizeof(_v1)); \
  } \
  inline bool operator!=(const type &_v1, const type &_v2) { \
    return !operator==(_v1, _v2); \
  } \
}
 
#define CRYPTO_MAKE_COMPARABLE_CONSTANT_TIME(type) \
namespace crypto { \
  inline bool operator==(const type &_v1, const type &_v2) { \
    static_assert(sizeof(_v1) == 32, "constant time comparison is only implenmted for 32 bytes"); \
    return crypto_verify_32((const unsigned char*)&_v1, (const unsigned char*)&_v2) == 0; \
  } \
  inline bool operator!=(const type &_v1, const type &_v2) { \
    return !operator==(_v1, _v2); \
  } \
}
 
namespace crypto {
  inline std::size_t siphash_to_size_t(const void *data, std::size_t length) {
    static_assert(sizeof(crypto_siphash_key) == crypto_shorthash_siphash24_KEYBYTES,
      "crypto_siphash_key size must match the SipHash-2-4 key length");
    static_assert(sizeof(std::uint64_t) == crypto_shorthash_siphash24_BYTES,
      "std::uint64_t size must match the SipHash-2-4 digest length");
    std::uint64_t h;
    crypto_shorthash_siphash24(reinterpret_cast<unsigned char*>(&h), static_cast<const unsigned char*>(data), length, crypto_siphash_key);
    return h;
  }
}
 
#define CRYPTO_DEFINE_HASH_FUNCTIONS(type) \
namespace crypto { \
  inline std::size_t hash_value(const type &_v) { \
    return siphash_to_size_t(std::addressof(_v), sizeof(_v)); \
  } \
} \
namespace std { \
  template<> \
  struct hash<crypto::type> { \
    std::size_t operator()(const crypto::type &_v) const { \
      return ::crypto::siphash_to_size_t(std::addressof(_v), sizeof(_v)); \
    } \
  }; \
}
 
#define CRYPTO_MAKE_HASHABLE(type) \
CRYPTO_MAKE_COMPARABLE(type) \
CRYPTO_DEFINE_HASH_FUNCTIONS(type)
 
#define CRYPTO_MAKE_HASHABLE_CONSTANT_TIME(type) \
CRYPTO_MAKE_COMPARABLE_CONSTANT_TIME(type) \
CRYPTO_DEFINE_HASH_FUNCTIONS(type)