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Diffstat (limited to 'indra/llcommon/lltypeinfolookup.h')
-rwxr-xr-x | indra/llcommon/lltypeinfolookup.h | 117 |
1 files changed, 0 insertions, 117 deletions
diff --git a/indra/llcommon/lltypeinfolookup.h b/indra/llcommon/lltypeinfolookup.h deleted file mode 100755 index 0b6862444e..0000000000 --- a/indra/llcommon/lltypeinfolookup.h +++ /dev/null @@ -1,117 +0,0 @@ -/** - * @file lltypeinfolookup.h - * @author Nat Goodspeed - * @date 2012-04-08 - * @brief Template data structure like std::map<std::type_info*, T> - * - * $LicenseInfo:firstyear=2012&license=viewerlgpl$ - * Copyright (c) 2012, Linden Research, Inc. - * $/LicenseInfo$ - */ - -#if ! defined(LL_LLTYPEINFOLOOKUP_H) -#define LL_LLTYPEINFOLOOKUP_H - -#include <boost/unordered_map.hpp> -#include <boost/functional/hash.hpp> -#include <boost/optional.hpp> -#include <functional> // std::binary_function -#include <typeinfo> - -/** - * The following helper classes are based on the Boost.Unordered documentation: - * http://www.boost.org/doc/libs/1_45_0/doc/html/unordered/hash_equality.html - */ - -/** - * Compute hash for a string passed as const char* - */ -struct const_char_star_hash: public std::unary_function<const char*, std::size_t> -{ - std::size_t operator()(const char* str) const - { - std::size_t seed = 0; - for ( ; *str; ++str) - { - boost::hash_combine(seed, *str); - } - return seed; - } -}; - -/** - * Compute equality for strings passed as const char* - * - * I (nat) suspect that this is where the default behavior breaks for the - * const char* values returned from std::type_info::name(). If you compare the - * two const char* pointer values, as a naive, unspecialized implementation - * will surely do, they'll compare unequal. - */ -struct const_char_star_equal: public std::binary_function<const char*, const char*, bool> -{ - bool operator()(const char* lhs, const char* rhs) const - { - return strcmp(lhs, rhs) == 0; - } -}; - -/** - * LLTypeInfoLookup is specifically designed for use cases for which you might - * consider std::map<std::type_info*, VALUE>. We have several such data - * structures in the viewer. The trouble with them is that at least on Linux, - * you can't rely on always getting the same std::type_info* for a given type: - * different load modules will produce different std::type_info*. - * LLTypeInfoLookup contains a workaround to address this issue. - * - * The API deliberately diverges from std::map in several respects: - * * It avoids iterators, not only begin()/end() but also as return values - * from insert() and find(). This bypasses transform_iterator overhead. - * * Since we literally use compile-time types as keys, the essential insert() - * and find() methods accept the key type as a @em template parameter, - * accepting and returning value_type as a normal runtime value. This is to - * permit future optimization (e.g. compile-time type hashing) without - * changing the API. - */ -template <typename VALUE> -class LLTypeInfoLookup -{ - // Use this for our underlying implementation: lookup by - // std::type_info::name() string. This is one of the rare cases in which I - // dare use const char* directly, rather than std::string, because I'm - // sure that every value returned by std::type_info::name() is static. - // HOWEVER, specify our own hash + equality functors: naively comparing - // distinct const char* values won't work. - typedef boost::unordered_map<const char*, VALUE, - const_char_star_hash, const_char_star_equal> impl_map_type; - -public: - typedef VALUE value_type; - - LLTypeInfoLookup() {} - - bool empty() const { return mMap.empty(); } - std::size_t size() const { return mMap.size(); } - - template <typename KEY> - bool insert(const value_type& value) - { - // Obtain and store the std::type_info::name() string as the key. - // Return just the bool from std::map::insert()'s return pair. - return mMap.insert(typename impl_map_type::value_type(typeid(KEY).name(), value)).second; - } - - template <typename KEY> - boost::optional<value_type> find() const - { - // Use the std::type_info::name() string as the key. - typename impl_map_type::const_iterator found = mMap.find(typeid(KEY).name()); - if (found == mMap.end()) - return boost::optional<value_type>(); - return found->second; - } - -private: - impl_map_type mMap; -}; - -#endif /* ! defined(LL_LLTYPEINFOLOOKUP_H) */ |