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LSST Applications 28.0.0,g1653933729+a8ce1bb630,g1a997c3884+a8ce1bb630,g28da252d5a+5bd70b7e6d,g2bbee38e9b+638fca75ac,g2bc492864f+638fca75ac,g3156d2b45e+07302053f8,g347aa1857d+638fca75ac,g35bb328faa+a8ce1bb630,g3a166c0a6a+638fca75ac,g3e281a1b8c+7bbb0b2507,g4005a62e65+17cd334064,g414038480c+5b5cd4fff3,g41af890bb2+4ffae9de63,g4e1a3235cc+0f1912dca3,g6249c6f860+3c3976f90c,g80478fca09+46aba80bd6,g82479be7b0+77990446f6,g858d7b2824+78ba4d1ce1,g89c8672015+f667a5183b,g9125e01d80+a8ce1bb630,ga5288a1d22+2a6264e9ca,gae0086650b+a8ce1bb630,gb58c049af0+d64f4d3760,gc22bb204ba+78ba4d1ce1,gc28159a63d+638fca75ac,gcf0d15dbbd+32ddb6096f,gd6b7c0dfd1+3e339405e9,gda3e153d99+78ba4d1ce1,gda6a2b7d83+32ddb6096f,gdaeeff99f8+1711a396fd,gdd5a9049c5+b18c39e5e3,ge2409df99d+a5e4577cdc,ge33fd446bb+78ba4d1ce1,ge79ae78c31+638fca75ac,gf0baf85859+64e8883e75,gf5289d68f6+e1b046a8d7,gfa443fc69c+91d9ed1ecf,gfda6b12a05+8419469a56
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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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21 */
22#ifndef LSST_CPPUTILS_HASH_COMBINE_H
23#define LSST_CPPUTILS_HASH_COMBINE_H
24
25#include <functional>
26
27namespace lsst {
28namespace cpputils {
29
35inline 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>
62template <typename T, typename... Rest>
63std::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>
92template <typename InputIterator>
93std::size_t hashIterable(std::size_t seed, InputIterator begin, InputIterator end) noexcept {
95 for (; begin != end; ++begin) {
96 result = hashCombine(result, *begin);
97 }
98 return result;
99}
100
101}
102namespace utils = cpputils;
103} // namespace lsst::cpputils
104
105#endif
py::object result
Definition _schema.cc:429
int end
T begin(T... args)
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