1 | //////////////////////////////////////////////////////////////////////////////// |
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2 | // The Loki Library |
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3 | // Copyright (c) 2001 by Andrei Alexandrescu |
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4 | // This code accompanies the book: |
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5 | // Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design |
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6 | // Patterns Applied". Copyright (c) 2001. Addison-Wesley. |
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7 | // Permission to use, copy, modify, distribute and sell this software for any |
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8 | // purpose is hereby granted without fee, provided that the above copyright |
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9 | // notice appear in all copies and that both that copyright notice and this |
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10 | // permission notice appear in supporting documentation. |
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11 | // The author or Addison-Welsey Longman make no representations about the |
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12 | // suitability of this software for any purpose. It is provided "as is" |
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13 | // without express or implied warranty. |
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14 | // |
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15 | // Changes by Orxonox (Reto Grieder) |
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16 | // Removed templates we didn't need |
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17 | //////////////////////////////////////////////////////////////////////////////// |
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18 | #ifndef LOKI_TYPEMANIP_INC_ |
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19 | #define LOKI_TYPEMANIP_INC_ |
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20 | |
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21 | // $Id: TypeManip.h 749 2006-10-17 19:49:26Z syntheticpp $ |
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22 | |
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23 | |
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24 | namespace Loki |
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25 | { |
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26 | //////////////////////////////////////////////////////////////////////////////// |
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27 | // class template Int2Type |
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28 | // Converts each integral constant into a unique type |
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29 | // Invocation: Int2Type<v> where v is a compile-time constant integral |
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30 | // Defines 'value', an enum that evaluates to v |
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31 | //////////////////////////////////////////////////////////////////////////////// |
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32 | |
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33 | template <int v> |
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34 | struct Int2Type |
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35 | { |
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36 | enum { value = v }; |
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37 | }; |
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38 | |
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39 | //////////////////////////////////////////////////////////////////////////////// |
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40 | // class template Type2Type |
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41 | // Converts each type into a unique, insipid type |
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42 | // Invocation Type2Type<T> where T is a type |
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43 | // Defines the type OriginalType which maps back to T |
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44 | //////////////////////////////////////////////////////////////////////////////// |
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45 | |
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46 | template <typename T> |
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47 | struct Type2Type |
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48 | { |
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49 | typedef T OriginalType; |
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50 | }; |
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51 | |
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52 | //////////////////////////////////////////////////////////////////////////////// |
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53 | // class template Select |
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54 | // Selects one of two types based upon a boolean constant |
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55 | // Invocation: Select<flag, T, U>::Result |
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56 | // where: |
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57 | // flag is a compile-time boolean constant |
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58 | // T and U are types |
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59 | // Result evaluates to T if flag is true, and to U otherwise. |
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60 | //////////////////////////////////////////////////////////////////////////////// |
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61 | |
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62 | template <bool flag, typename T, typename U> |
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63 | struct Select |
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64 | { |
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65 | typedef T Result; |
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66 | }; |
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67 | template <typename T, typename U> |
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68 | struct Select<false, T, U> |
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69 | { |
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70 | typedef U Result; |
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71 | }; |
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72 | |
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73 | //////////////////////////////////////////////////////////////////////////////// |
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74 | // class template IsSameType |
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75 | // Return true iff two given types are the same |
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76 | // Invocation: SameType<T, U>::value |
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77 | // where: |
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78 | // T and U are types |
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79 | // Result evaluates to true iff U == T (types equal) |
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80 | //////////////////////////////////////////////////////////////////////////////// |
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81 | |
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82 | template <typename T, typename U> |
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83 | struct IsSameType |
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84 | { |
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85 | enum { value = false }; |
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86 | }; |
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87 | |
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88 | template <typename T> |
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89 | struct IsSameType<T,T> |
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90 | { |
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91 | enum { value = true }; |
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92 | }; |
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93 | |
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94 | } // namespace Loki |
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95 | |
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96 | |
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97 | #endif // end file guardian |
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98 | |
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