diff options
Diffstat (limited to 'indra/llcommon/llstl.h')
| -rwxr-xr-x | indra/llcommon/llstl.h | 200 |
1 files changed, 194 insertions, 6 deletions
diff --git a/indra/llcommon/llstl.h b/indra/llcommon/llstl.h index 6a539c2b91..0435cb8a08 100755 --- a/indra/llcommon/llstl.h +++ b/indra/llcommon/llstl.h @@ -28,13 +28,12 @@ #define LL_LLSTL_H #include "stdtypes.h" - #include <functional> #include <algorithm> #include <map> #include <vector> +#include <list> #include <set> -#include <deque> #include <typeinfo> // Use to compare the first element only of a pair @@ -127,7 +126,7 @@ struct DeletePairedPointerArray // compiler, the second unary_function template parameter can be set // to void. // -// Here's a snippit showing how you use this object: +// Here's a snippet showing how you use this object: // // typedef std::map<int, widget*> map_type; // map_type widget_map; @@ -172,6 +171,49 @@ struct CopyNewPointer } }; +template<typename T, typename ALLOC> +void delete_and_clear(std::list<T*, ALLOC>& list) +{ + std::for_each(list.begin(), list.end(), DeletePointer()); + list.clear(); +} + +template<typename T, typename ALLOC> +void delete_and_clear(std::vector<T*, ALLOC>& vector) +{ + std::for_each(vector.begin(), vector.end(), DeletePointer()); + vector.clear(); +} + +template<typename T, typename COMPARE, typename ALLOC> +void delete_and_clear(std::set<T*, COMPARE, ALLOC>& set) +{ + std::for_each(set.begin(), set.end(), DeletePointer()); + set.clear(); +} + +template<typename K, typename V, typename COMPARE, typename ALLOC> +void delete_and_clear(std::map<K, V*, COMPARE, ALLOC>& map) +{ + std::for_each(map.begin(), map.end(), DeletePairedPointer()); + map.clear(); +} + +template<typename T> +void delete_and_clear(T*& ptr) +{ + delete ptr; + ptr = NULL; +} + + +template<typename T> +void delete_and_clear_array(T*& ptr) +{ + delete[] ptr; + ptr = NULL; +} + // Simple function to help with finding pointers in maps. // For example: // typedef map_t; @@ -240,8 +282,8 @@ inline T get_if_there(const std::map<K,T>& inmap, const K& key, T default_value) // else // ++iter; // } -template <typename T, typename Iter> -inline Iter vector_replace_with_last(std::vector<T>& invec, Iter iter) +template <typename T> +inline typename std::vector<T>::iterator vector_replace_with_last(std::vector<T>& invec, typename std::vector<T>::iterator iter) { typename std::vector<T>::iterator last = invec.end(); --last; if (iter == invec.end()) @@ -261,7 +303,6 @@ inline Iter vector_replace_with_last(std::vector<T>& invec, Iter iter) } }; -// Useful for replacing the removeObj() functionality of LLDynamicArray // Example: // vector_replace_with_last(mList, x); template <typename T> @@ -524,4 +565,151 @@ namespace std }; } // std + +/** + * Implementation for ll_template_cast() (q.v.). + * + * Default implementation: trying to cast two completely unrelated types + * returns 0. Typically you'd specify T and U as pointer types, but in fact T + * can be any type that can be initialized with 0. + */ +template <typename T, typename U> +struct ll_template_cast_impl +{ + T operator()(U) + { + return 0; + } +}; + +/** + * ll_template_cast<T>(some_value) is for use in a template function when + * some_value might be of arbitrary type, but you want to recognize type T + * specially. + * + * It's designed for use with pointer types. Example: + * @code + * struct SpecialClass + * { + * void someMethod(const std::string&) const; + * }; + * + * template <class REALCLASS> + * void somefunc(const REALCLASS& instance) + * { + * const SpecialClass* ptr = ll_template_cast<const SpecialClass*>(&instance); + * if (ptr) + * { + * ptr->someMethod("Call method only available on SpecialClass"); + * } + * } + * @endcode + * + * Why is this better than dynamic_cast<>? Because unless OtherClass is + * polymorphic, the following won't even compile (gcc 4.0.1): + * @code + * OtherClass other; + * SpecialClass* ptr = dynamic_cast<SpecialClass*>(&other); + * @endcode + * to say nothing of this: + * @code + * void function(int); + * SpecialClass* ptr = dynamic_cast<SpecialClass*>(&function); + * @endcode + * ll_template_cast handles these kinds of cases by returning 0. + */ +template <typename T, typename U> +T ll_template_cast(U value) +{ + return ll_template_cast_impl<T, U>()(value); +} + +/** + * Implementation for ll_template_cast() (q.v.). + * + * Implementation for identical types: return same value. + */ +template <typename T> +struct ll_template_cast_impl<T, T> +{ + T operator()(T value) + { + return value; + } +}; + +/** + * LL_TEMPLATE_CONVERTIBLE(dest, source) asserts that, for a value @c s of + * type @c source, <tt>ll_template_cast<dest>(s)</tt> will return @c s -- + * presuming that @c source can be converted to @c dest by the normal rules of + * C++. + * + * By default, <tt>ll_template_cast<dest>(s)</tt> will return 0 unless @c s's + * type is literally identical to @c dest. (This is because of the + * straightforward application of template specialization rules.) That can + * lead to surprising results, e.g.: + * + * @code + * Foo myFoo; + * const Foo* fooptr = ll_template_cast<const Foo*>(&myFoo); + * @endcode + * + * Here @c fooptr will be 0 because <tt>&myFoo</tt> is of type <tt>Foo*</tt> + * -- @em not <tt>const Foo*</tt>. (Declaring <tt>const Foo myFoo;</tt> would + * force the compiler to do the right thing.) + * + * More disappointingly: + * @code + * struct Base {}; + * struct Subclass: public Base {}; + * Subclass object; + * Base* ptr = ll_template_cast<Base*>(&object); + * @endcode + * + * Here @c ptr will be 0 because <tt>&object</tt> is of type + * <tt>Subclass*</tt> rather than <tt>Base*</tt>. We @em want this cast to + * succeed, but without our help ll_template_cast can't recognize it. + * + * The following would suffice: + * @code + * LL_TEMPLATE_CONVERTIBLE(Base*, Subclass*); + * ... + * Base* ptr = ll_template_cast<Base*>(&object); + * @endcode + * + * However, as noted earlier, this is easily fooled: + * @code + * const Base* ptr = ll_template_cast<const Base*>(&object); + * @endcode + * would still produce 0 because we haven't yet seen: + * @code + * LL_TEMPLATE_CONVERTIBLE(const Base*, Subclass*); + * @endcode + * + * @TODO + * This macro should use Boost type_traits facilities for stripping and + * re-adding @c const and @c volatile qualifiers so that invoking + * LL_TEMPLATE_CONVERTIBLE(dest, source) will automatically generate all + * permitted permutations. It's really not fair to the coder to require + * separate: + * @code + * LL_TEMPLATE_CONVERTIBLE(Base*, Subclass*); + * LL_TEMPLATE_CONVERTIBLE(const Base*, Subclass*); + * LL_TEMPLATE_CONVERTIBLE(const Base*, const Subclass*); + * @endcode + * + * (Naturally we omit <tt>LL_TEMPLATE_CONVERTIBLE(Base*, const Subclass*)</tt> + * because that's not permitted by normal C++ assignment anyway.) + */ +#define LL_TEMPLATE_CONVERTIBLE(DEST, SOURCE) \ +template <> \ +struct ll_template_cast_impl<DEST, SOURCE> \ +{ \ + DEST operator()(SOURCE wrapper) \ + { \ + return wrapper; \ + } \ +} + + #endif // LL_LLSTL_H |