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crypto: constexpr_floor_log_n, constexpr_ceil_log_n + tests

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sowle 2023-03-23 23:30:56 +01:00
parent a13cb94214
commit beccc55788
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2 changed files with 62 additions and 15 deletions
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15
src/crypto/range_proofs.h
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@ -24,18 +24,25 @@ namespace crypto
}
// returns greatest k, s.t. 2**k <= v
// returns greatest k, s.t. n**k <= v
// tests in crypto_tests_range_proofs.h
constexpr size_t constexpr_floor_log2(size_t v)
constexpr size_t constexpr_floor_log_n(size_t v, size_t n)
{
return v <= 1 ? 0 : constexpr_floor_log2(v >> 1) + 1;
return (v < n || n <= 1) ? 0 : constexpr_floor_log_n(v / n, n) + 1;
}
// returns smallest k, s.t. v <= n**k
// tests in crypto_tests_range_proofs.h
constexpr size_t constexpr_ceil_log_n(size_t v, size_t n)
{
return (v <= 1 || n <= 1) ? 0 : constexpr_floor_log_n(v - 1, n) + 1;
}
// returns smallest k, s.t. v <= 2**k
// tests in crypto_tests_range_proofs.h
constexpr size_t constexpr_ceil_log2(size_t v)
{
return v <= 1 ? 0 : constexpr_floor_log2(v - 1) + 1;
return constexpr_ceil_log_n(v, 2);
}

62
tests/functional_tests/crypto_tests_range_proofs.h
View file

@ -25,17 +25,57 @@ bool wip_vandermonde(const scalar_vec_t& av, const scalar_vec_t& bv, const scala
}
static_assert(constexpr_floor_log2(0) == 0, "");
static_assert(constexpr_floor_log2(1) == 0, "");
static_assert(constexpr_floor_log2(2) == 1, "");
static_assert(constexpr_floor_log2(3) == 1, "");
static_assert(constexpr_floor_log2(4) == 2, "");
static_assert(constexpr_floor_log2(5) == 2, "");
static_assert(constexpr_floor_log2(64) == 6, "");
static_assert(constexpr_floor_log2(100) == 6, "");
static_assert(constexpr_floor_log2(100000000) == 26, "");
static_assert(constexpr_floor_log2(0x7fffffffffffffff) == 62, "");
static_assert(constexpr_floor_log2(SIZE_MAX) == 63, "");
static_assert(constexpr_floor_log_n(0, 2) == 0, "");
static_assert(constexpr_floor_log_n(1, 2) == 0, "");
static_assert(constexpr_floor_log_n(2, 2) == 1, "");
static_assert(constexpr_floor_log_n(3, 2) == 1, "");
static_assert(constexpr_floor_log_n(4, 2) == 2, "");
static_assert(constexpr_floor_log_n(5, 2) == 2, "");
static_assert(constexpr_floor_log_n(64, 2) == 6, "");
static_assert(constexpr_floor_log_n(100, 2) == 6, "");
static_assert(constexpr_floor_log_n(100000000, 2) == 26, "");
static_assert(constexpr_floor_log_n(0x7fffffffffffffff, 2) == 62, "");
static_assert(constexpr_floor_log_n(SIZE_MAX, 2) == 63, "");
static_assert(constexpr_floor_log_n(0, 0) == 0, "");
static_assert(constexpr_floor_log_n(1, 0) == 0, "");
static_assert(constexpr_floor_log_n(2, 0) == 0, "");
static_assert(constexpr_floor_log_n(100, 0) == 0, "");
static_assert(constexpr_floor_log_n(1, 3) == 0, "");
static_assert(constexpr_floor_log_n(2, 3) == 0, "");
static_assert(constexpr_floor_log_n(3, 3) == 1, "");
static_assert(constexpr_floor_log_n(8, 3) == 1, "");
static_assert(constexpr_floor_log_n(9, 3) == 2, "");
static_assert(constexpr_floor_log_n(26, 3) == 2, "");
static_assert(constexpr_floor_log_n(27, 3) == 3, "");
static_assert(constexpr_floor_log_n(100, 3) == 4, "");
static_assert(constexpr_floor_log_n(531441, 3) == 12, "");
static_assert(constexpr_floor_log_n(0x7fffffffffffffff, 3) == 39, "");
static_assert(constexpr_floor_log_n(SIZE_MAX, 3) == 40, "");
static_assert(constexpr_ceil_log_n(0, 0) == 0, "");
static_assert(constexpr_ceil_log_n(0, 1) == 0, "");
static_assert(constexpr_ceil_log_n(0, 2) == 0, "");
static_assert(constexpr_ceil_log_n(1, 0) == 0, "");
static_assert(constexpr_ceil_log_n(2, 0) == 0, "");
static_assert(constexpr_ceil_log_n(1, 1) == 0, "");
static_assert(constexpr_ceil_log_n(1, 2) == 0, "");
static_assert(constexpr_ceil_log_n(2, 1) == 0, "");
static_assert(constexpr_ceil_log_n(0, 5) == 0, "");
static_assert(constexpr_ceil_log_n(1, 5) == 0, "");
static_assert(constexpr_ceil_log_n(4, 5) == 1, "");
static_assert(constexpr_ceil_log_n(5, 5) == 1, "");
static_assert(constexpr_ceil_log_n(6, 5) == 2, "");
static_assert(constexpr_ceil_log_n(25, 5) == 2, "");
static_assert(constexpr_ceil_log_n(100, 5) == 3, "");
static_assert(constexpr_ceil_log_n(624, 5) == 4, "");
static_assert(constexpr_ceil_log_n(625, 5) == 4, "");
static_assert(constexpr_ceil_log_n(626, 5) == 5, "");
static_assert(constexpr_ceil_log_n(100000000, 5) == 12, "");
static_assert(constexpr_ceil_log_n(0x7fffffffffffffff, 5) == 28, "");
static_assert(constexpr_ceil_log_n(SIZE_MAX, 5) == 28, "");
static_assert(constexpr_ceil_log2(0) == 0, "");
static_assert(constexpr_ceil_log2(1) == 0, "");