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Fixes #60 ("Licensing question for math.hpp"). Removes questioned, SO-based code since it was just an alternative version for non-MSVC/non-GCC compatible compilers.

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Ion Gaztañaga
2021-04-18 14:10:53 +02:00
parent 3c75cad9ab
commit 1cec79608f
2 changed files with 2 additions and 48 deletions
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3
doc/intrusive.qbk
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@@ -3889,7 +3889,8 @@ to be inserted in intrusive containers are allocated using `std::vector` or `std
[section:release_notes_boost_1_77_00 Boost 1.77 Release] [section:release_notes_boost_1_77_00 Boost 1.77 Release]
* Fixed bugs: * Fixed bugs:
* [@https://github.com/boostorg/intrusive/pull/57 GitHub #57: ['UB: comparing unrelated pointers]] * [@https://github.com/boostorg/intrusive/pull/57 GitHub #57: ['UB: comparing unrelated pointers]]
* [@https://github.com/boostorg/intrusive/issues/60 GitHub #60: ['Licensing question for math.hpp]]
[endsect] [endsect]

47
include/boost/intrusive/detail/math.hpp
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@@ -150,53 +150,6 @@ namespace detail {
return log2; return log2;
} }
////////////////////////////
// DeBruijn method
////////////////////////////
//Taken from:
//http://stackoverflow.com/questions/11376288/fast-computing-of-log2-for-64-bit-integers
//Thanks to Desmond Hume
inline std::size_t floor_log2 (std::size_t v, integral_constant<std::size_t, 32>)
{
static const int MultiplyDeBruijnBitPosition[32] =
{
0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
};
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
return MultiplyDeBruijnBitPosition[(std::size_t)(v * 0x07C4ACDDU) >> 27];
}
inline std::size_t floor_log2 (std::size_t v, integral_constant<std::size_t, 64>)
{
static const std::size_t MultiplyDeBruijnBitPosition[64] = {
63, 0, 58, 1, 59, 47, 53, 2,
60, 39, 48, 27, 54, 33, 42, 3,
61, 51, 37, 40, 49, 18, 28, 20,
55, 30, 34, 11, 43, 14, 22, 4,
62, 57, 46, 52, 38, 26, 32, 41,
50, 36, 17, 19, 29, 10, 13, 21,
56, 45, 25, 31, 35, 16, 9, 12,
44, 24, 15, 8, 23, 7, 6, 5};
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
v |= v >> 32;
return MultiplyDeBruijnBitPosition[((std::size_t)((v - (v >> 1))*0x07EDD5E59A4E28C2ULL)) >> 58];
}
inline std::size_t floor_log2 (std::size_t x) inline std::size_t floor_log2 (std::size_t x)
{ {
const std::size_t Bits = sizeof(std::size_t)*CHAR_BIT; const std::size_t Bits = sizeof(std::size_t)*CHAR_BIT;