Last change
on this file since 45 was
29,
checked in by landauf, 17 years ago
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updated boost from 1_33_1 to 1_34_1
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File size:
1.2 KB
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1 | |
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2 | // Copyright Daniel James 2005-2006. Use, modification, and distribution are |
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3 | // subject to the Boost Software License, Version 1.0. (See accompanying |
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4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
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5 | |
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6 | #include <boost/functional/hash.hpp> |
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7 | #include <cassert> |
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8 | |
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9 | // This example illustrates how to customise boost::hash portably, so that |
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10 | // it'll work on both compilers that don't implement argument dependent lookup |
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11 | // and compilers that implement strict two-phase template instantiation. |
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12 | |
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13 | namespace foo |
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14 | { |
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15 | template <class T> |
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16 | class custom_type |
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17 | { |
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18 | T value; |
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19 | public: |
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20 | custom_type(T x) : value(x) {} |
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21 | |
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22 | std::size_t hash() const |
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23 | { |
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24 | boost::hash<T> hasher; |
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25 | return hasher(value); |
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26 | } |
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27 | }; |
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28 | } |
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29 | |
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30 | #ifdef BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP |
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31 | namespace boost |
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32 | #else |
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33 | namespace foo |
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34 | #endif |
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35 | { |
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36 | template <class T> |
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37 | std::size_t hash_value(foo::custom_type<T> x) |
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38 | { |
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39 | return x.hash(); |
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40 | } |
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41 | } |
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42 | |
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43 | int main() |
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44 | { |
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45 | foo::custom_type<int> x(1), y(2), z(1); |
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46 | |
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47 | boost::hash<foo::custom_type<int> > hasher; |
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48 | |
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49 | assert(hasher(x) == hasher(x)); |
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50 | assert(hasher(x) != hasher(y)); |
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51 | assert(hasher(x) == hasher(z)); |
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52 | |
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53 | return 0; |
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54 | } |
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