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author | Remko Tronçon <git@el-tramo.be> | 2010-05-06 18:00:41 (GMT) |
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committer | Remko Tronçon <git@el-tramo.be> | 2010-05-06 18:00:41 (GMT) |
commit | 4c58e9a2d266c23a2060edd08081bf86ebd1862c (patch) | |
tree | 0030a4f3360c9da905165db1feed18997481fee5 /3rdParty/Boost/src/boost/random/detail/signed_unsigned_tools.hpp | |
parent | c2cf7f0e59c7880a9ce979d8a45d97442c705110 (diff) | |
download | swift-contrib-4c58e9a2d266c23a2060edd08081bf86ebd1862c.zip swift-contrib-4c58e9a2d266c23a2060edd08081bf86ebd1862c.tar.bz2 |
Use UUIDs as nonce when authenticating with SCRAM-SHA-1.
Diffstat (limited to '3rdParty/Boost/src/boost/random/detail/signed_unsigned_tools.hpp')
-rw-r--r-- | 3rdParty/Boost/src/boost/random/detail/signed_unsigned_tools.hpp | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/3rdParty/Boost/src/boost/random/detail/signed_unsigned_tools.hpp b/3rdParty/Boost/src/boost/random/detail/signed_unsigned_tools.hpp new file mode 100644 index 0000000..3c81cf4 --- /dev/null +++ b/3rdParty/Boost/src/boost/random/detail/signed_unsigned_tools.hpp @@ -0,0 +1,89 @@ +/* boost random/detail/signed_unsigned_tools.hpp header file + * + * Copyright Jens Maurer 2006 + * Distributed under the Boost Software License, Version 1.0. (See + * accompanying file LICENSE_1_0.txt or copy at + * http://www.boost.org/LICENSE_1_0.txt) + * + * See http://www.boost.org for most recent version including documentation. + */ + +#ifndef BOOST_RANDOM_DETAIL_SIGNED_UNSIGNED_TOOLS +#define BOOST_RANDOM_DETAIL_SIGNED_UNSIGNED_TOOLS + +#include <boost/limits.hpp> +#include <boost/config.hpp> +#include <boost/type_traits/make_unsigned.hpp> + +namespace boost { +namespace random { +namespace detail { + + +/* + * Compute x - y, we know that x >= y, return an unsigned value. + */ + +template<class T, bool sgn = std::numeric_limits<T>::is_signed> +struct subtract { }; + +template<class T> +struct subtract<T, /* signed */ false> +{ + typedef T result_type; + result_type operator()(T x, T y) { return x - y; } +}; + +template<class T> +struct subtract<T, /* signed */ true> +{ + typedef typename make_unsigned<T>::type result_type; + result_type operator()(T x, T y) + { + if (y >= 0) // because x >= y, it follows that x >= 0, too + return result_type(x) - result_type(y); + if (x >= 0) // y < 0 + // avoid the nasty two's complement case for y == min() + return result_type(x) + result_type(-(y+1)) + 1; + // both x and y are negative: no signed overflow + return result_type(x - y); + } +}; + +/* + * Compute x + y, x is unsigned, result fits in type of "y". + */ + +template<class T1, class T2, bool sgn = std::numeric_limits<T2>::is_signed> +struct add { }; + +template<class T1, class T2> +struct add<T1, T2, /* signed */ false> +{ + typedef T2 result_type; + result_type operator()(T1 x, T2 y) { return T2(x) + y; } +}; + +template<class T1, class T2> +struct add<T1, T2, /* signed */ true> +{ + typedef T2 result_type; + result_type operator()(T1 x, T2 y) + { + if (y >= 0) + return T2(x) + y; + // y < 0 + if (x >= T1(-(y+1))) // result >= 0 after subtraction + // avoid the nasty two's complement edge case for y == min() + return T2(x - T1(-(y+1)) - 1); + // abs(x) < abs(y), thus T2 able to represent x + return T2(x) + y; + } +}; + +} // namespace detail +} // namespace random +} // namespace boost + +#endif // BOOST_RANDOM_DETAIL_SIGNED_UNSIGNED_TOOLS + |