LSST Applications  21.0.0-172-gfb10e10a+18fedfabac,22.0.0+297cba6710,22.0.0+80564b0ff1,22.0.0+8d77f4f51a,22.0.0+a28f4c53b1,22.0.0+dcf3732eb2,22.0.1-1-g7d6de66+2a20fdde0d,22.0.1-1-g8e32f31+297cba6710,22.0.1-1-geca5380+7fa3b7d9b6,22.0.1-12-g44dc1dc+2a20fdde0d,22.0.1-15-g6a90155+515f58c32b,22.0.1-16-g9282f48+790f5f2caa,22.0.1-2-g92698f7+dcf3732eb2,22.0.1-2-ga9b0f51+7fa3b7d9b6,22.0.1-2-gd1925c9+bf4f0e694f,22.0.1-24-g1ad7a390+a9625a72a8,22.0.1-25-g5bf6245+3ad8ecd50b,22.0.1-25-gb120d7b+8b5510f75f,22.0.1-27-g97737f7+2a20fdde0d,22.0.1-32-gf62ce7b1+aa4237961e,22.0.1-4-g0b3f228+2a20fdde0d,22.0.1-4-g243d05b+871c1b8305,22.0.1-4-g3a563be+32dcf1063f,22.0.1-4-g44f2e3d+9e4ab0f4fa,22.0.1-42-gca6935d93+ba5e5ca3eb,22.0.1-5-g15c806e+85460ae5f3,22.0.1-5-g58711c4+611d128589,22.0.1-5-g75bb458+99c117b92f,22.0.1-6-g1c63a23+7fa3b7d9b6,22.0.1-6-g50866e6+84ff5a128b,22.0.1-6-g8d3140d+720564cf76,22.0.1-6-gd805d02+cc5644f571,22.0.1-8-ge5750ce+85460ae5f3,master-g6e05de7fdc+babf819c66,master-g99da0e417a+8d77f4f51a,w.2021.48
LSST Data Management Base Package
hashCombine.h
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1 /*
2  * LSST Data Management System
3  * See COPYRIGHT file at the top of the source tree.
4  *
5  * This product includes software developed by the
6  * LSST Project (http://www.lsst.org/).
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22 #ifndef LSST_CPPUTILS_HASH_COMBINE_H
23 #define LSST_CPPUTILS_HASH_COMBINE_H
24 
25 #include <functional>
26 
27 namespace lsst {
28 namespace cpputils {
29 
35 inline std::size_t hashCombine(std::size_t seed) noexcept { return seed; }
36 
59 // This implementation is provided by Matteo Italia, https://stackoverflow.com/a/38140932/834250
60 // Algorithm described at https://stackoverflow.com/a/27952689
61 // WARNING: should not be inline or constexpr; it can cause instantiation-order problems with std::hash<T>
62 template <typename T, typename... Rest>
63 std::size_t hashCombine(std::size_t seed, const T& value, Rest... rest) noexcept {
64  std::hash<T> hasher;
65  seed ^= hasher(value) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
66  return hashCombine(seed, rest...);
67 }
68 
90 // Note: not an overload of hashCombine to avoid ambiguity with hashCombine(size_t, T1, T2)
91 // WARNING: should not be inline or constexpr; it can cause instantiation-order problems with std::hash<T>
92 template <typename InputIterator>
93 std::size_t hashIterable(std::size_t seed, InputIterator begin, InputIterator end) noexcept {
94  std::size_t result = 0;
95  for (; begin != end; ++begin) {
96  result = hashCombine(result, *begin);
97  }
98  return result;
99 }
100 
101 }
102 namespace utils = cpputils;
103 } // namespace lsst::cpputils
104 
105 #endif
py::object result
Definition: _schema.cc:429
int end
std::size_t hashCombine(std::size_t seed) noexcept
Combine hashes.
Definition: hashCombine.h:35
std::size_t hashIterable(std::size_t seed, InputIterator begin, InputIterator end) noexcept
Combine hashes in an iterable.
Definition: hashCombine.h:93
A base class for image defects.