any.h

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/*
 *  OGF/Graphite: Geometry and Graphics Programming Library + Utilities
 *  Copyright (C) 2000 Bruno Levy
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  If you modify this software, you should include a notice giving the
 *  name of the person performing the modification, the date of modification,
 *  and the reason for such modification.
 *
 *  Contact: Bruno Levy
 *
 *     levy@loria.fr
 *
 *     ISA Project
 *     LORIA, INRIA Lorraine, 
 *     Campus Scientifique, BP 239
 *     54506 VANDOEUVRE LES NANCY CEDEX 
 *     FRANCE
 *
 *  Note that the GNU General Public License does not permit incorporating
 *  the Software into proprietary programs. 
 */
 
#ifndef H_OGF_BASIC_TYPES_ANY_H
#define H_OGF_BASIC_TYPES_ANY_H
 
#include <OGF/gom/common/common.h>
#include <OGF/gom/services/life_cycle.h>
#include <typeinfo>
 
#ifdef GEO_COMPILER_CLANG
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
#endif
 
 
namespace OGF {
 
    class MetaType;
 
    class GOM_API Any {
      private:
 
        enum { BUFFER_SIZE = 40 };      
 
      public:
 
        Any() : value_(nullptr), in_buffer_(false), meta_type_(nullptr) {
        }
 
        ~Any() {
            destroy();
        }
 
        bool is_null() const {
            return value_ == nullptr;
        }
 
        void reset() {
            destroy();
        }
        
        Any(const Any& rhs) :
            value_(nullptr), in_buffer_(false), meta_type_(nullptr) {
            copy(rhs);
        }
 
        Any& operator=(const Any& rhs) {
            if(&rhs != this) {
                destroy();
                copy(rhs);
            }
            return *this;
        }
        
        std::string as_string() const {
            std::string result;     
            if(value_ != nullptr) {
                convert_to_string(meta_type_, result, value_);
            }
            return result;
        }
 
        MetaType* meta_type() const {
            return meta_type_;
        }
 
        LifeCycle* life_cycle() const;
 
        template <class T> void set_value(const T& value) {
            MetaType* new_type = resolve_meta_type<T>();
            if(new_type == meta_type_) {
                life_cycle()->assign(value_, Memory::pointer(&value));
                return;
            }
            destroy();
            meta_type_ = new_type;
 
#if defined(GEO_COMPILER_GCC)       
// GCC does not see that we use placement new in the buffer
// only if object size is smaller than BUFFER_SIZE and
// generates a warning.     
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wplacement-new"
#elif defined(GEO_COMPILER_MSVC)
// MSVC barks on test with constant condition.      
#pragma warning(push)
#pragma warning(disable:4127)       
#endif      
            
            if(sizeof(T) <= BUFFER_SIZE) {
                in_buffer_ = true;
                value_ = buffer_;
                new(value_)T(value);
            } else {
                in_buffer_ = false;
                value_ = Memory::pointer(new T(value));
            }
 
#if defined(GEO_COMPILER_GCC)
#pragma GCC diagnostic pop
#elif defined(GEO_COMPILER_MSVC)
#pragma warning(pop)
#endif      
            
        }
 
        void set_value(const char* value) {
            set_value<std::string>(std::string(value));
        }
        
        template <class T> bool get_value(T& value) const {
            if(value_ == nullptr) {
                return false;
            }
            // Test if the stored value is of type T
            if(meta_type_ == resolve_meta_type<T>()) {
                value = value_as<T>();
                return true;
            }
            // If the stored value is a string, convert it to T
            if(meta_type_ == resolve_meta_type<std::string>()) {
                const std::string& string_value = value_as<std::string>();
                convert_from_string(
                    resolve_meta_type<T>(),
                    string_value, (Memory::pointer)(&value)
                );
                return true;
            }
            return false;
        }
 
        bool get_value(std::string& value) const {
            value = as_string();
            return true;
        }
 
        bool get_value(index_t& value) const {
            if(get_value<index_t>(value)) {
                return true;
            }
            {
                signed_index_t tmp;
                if(get_value<signed_index_t>(tmp)) {
                    value = index_t(tmp);
                    return true;
                }
            }
            {
                float tmp;
                if(get_value<float>(tmp)) {
                    value = index_t(tmp);
                    return true;
                }
                
            }
            {
                double tmp;
                if(get_value<double>(tmp)) {
                    value = index_t(tmp);
                    return true;
                }
                
            }
            return false;
        }
 
        bool get_value(signed_index_t& value) const {
            if(get_value<signed_index_t>(value)) {
                return true;
            }
            {
                index_t tmp;
                if(get_value<index_t>(tmp)) {
                    value = signed_index_t(tmp);
                    return true;
                }
            }
            {
                float tmp;
                if(get_value<float>(tmp)) {
                    value = signed_index_t(tmp);
                    return true;
                }
                
            }
            {
                double tmp;
                if(get_value<double>(tmp)) {
                    value = signed_index_t(tmp);
                    return true;
                }
                
            }
            return false;
        }
 
        bool get_value(float& value) const {
            if(get_value<float>(value)) {
                return true;
            }
            {
                double tmp;
                if(get_value<double>(tmp)) {
                    value = float(tmp);
                    return true;
                }
            }
            {
                index_t tmp;
                if(get_value<index_t>(tmp)) {
                    value = float(tmp);
                    return true;
                }
            }
            {
                signed_index_t tmp;
                if(get_value<signed_index_t>(tmp)) {
                    value = float(tmp);
                    return true;
                }
            }
            return false;
        }
 
        bool get_value(double& value) const {
            if(get_value<double>(value)) {
                return true;
            }
            {
                float tmp;
                if(get_value<float>(tmp)) {
                    value = double(tmp);
                    return true;
                }
            }
            {
                index_t tmp;
                if(get_value<index_t>(tmp)) {
                    value = double(tmp);
                    return true;
                }
            }
            {
                signed_index_t tmp;
                if(get_value<signed_index_t>(tmp)) {
                    value = double(tmp);
                    return true;
                }
            }
            return false;
        }
 
        template <class T> bool get_value(T*& value) const {
            value = nullptr;
            if(is_null()) {
                return true;
            }
 
            if(!is_pointer_type(meta_type())) {
                Logger::warn("GOM")
                    << "Invalid Any to pointer conversion: not pointer type "
                    << std::endl;
                Logger::warn("GOM")
                    << "type = "
                    << meta_type_name(meta_type())
                    << std::endl;
                Logger::warn("GOM")
                    << "value = "
                    << as_string()
                    << std::endl;
                return false;
            }
 
            /*
            // TODO: check pointer types ? (but I do not want to include
            // <meta.h> I think, to be checked).
            if(!pointer_can_be_casted_to(meta_type(), ogf_meta<T>::type())) {
                Logger::warn("GOM")
                    << "Invalid Any to pointer conversion: invalid cast"
                    << std::endl;
                return false;
            }
            */
            
            value = (T*)(value_as<Memory::pointer>());
            return true;
        }
 
        void create(MetaType* meta_type) {
            destroy();
            meta_type_ = meta_type;
            if(life_cycle()->object_size() <= BUFFER_SIZE) {
                in_buffer_ = true;
                value_ = buffer_;
                life_cycle()->construct(value_);
            } else {
                in_buffer_ = false;
                value_ = life_cycle()->new_object();
            }
        }
 
        void copy_from(Memory::pointer addr, MetaType* meta_type) {
            if(value_ != nullptr && this->meta_type() == meta_type) {
                life_cycle()->assign(value_, addr);
                return;
            }
            if(value_ != nullptr) {
                destroy();
            }
            meta_type_ = meta_type;
            if(life_cycle()->object_size() <= BUFFER_SIZE) {
                in_buffer_ = true;
                value_ = buffer_;
                life_cycle()->copy_construct(value_, addr);
            } else {
                in_buffer_ = false;
                value_ = life_cycle()->new_object(addr);
            }
        }
 
        bool copy_to(Memory::pointer addr, MetaType* meta_type) const {
            if(value_ == nullptr) {
                return false;
            }
            if(meta_type == this->meta_type()) {
                life_cycle()->assign(addr, value_);
                return true;
            }
            // If meta types do not match, try conversions.
            return copy_convert_to(addr, meta_type);
        }
        
        static void convert_to_string(
            MetaType* meta_type,
            std::string& string, Memory::pointer value
        );
 
        static void convert_from_string(
            MetaType* meta_type,
            const std::string& string, Memory::pointer value
        );
 
        static bool is_pointer_type(const MetaType* mtype);
 
        static MetaType* pointed_type(const MetaType* mtype);
 
        static bool pointer_can_be_casted_to(
            const MetaType* derived_pointer_type,           
            const MetaType* base_pointer_type
        );
 
        static MetaType* resolve_meta_type_by_typeid_name(
            const std::string& typeid_name
        );
 
        template <class T> static MetaType* resolve_meta_type() {
            static MetaType* mtype =
                resolve_meta_type_by_typeid_name(typeid(T).name());
            return mtype;
        }
 
      protected:
 
        bool copy_convert_to(Memory::pointer addr, MetaType* meta_type) const;
        
        template <class T> const T& value_as() const {
            return *(T*)(value_);
        }
 
        void destroy() {
            if(value_ == nullptr) {
                return;
            }
            if(in_buffer_) {
                life_cycle()->destroy(value_);
                in_buffer_ = false;
            } else {
                life_cycle()->delete_object(value_);            
            }
            value_ = nullptr;
            meta_type_ = nullptr;
        }
 
        void copy(const Any& rhs) {
            geo_debug_assert(&rhs != this);
            if(rhs.is_null()) {
                destroy();
                return;
            }
            meta_type_ = rhs.meta_type();
            if(life_cycle()->object_size() <= BUFFER_SIZE) {
                in_buffer_ = true;
                value_ = buffer_;
                life_cycle()->copy_construct(value_, rhs.value_);
            } else {
                in_buffer_ = false;
                value_ = life_cycle()->new_object(rhs.value_);
            }
        }
 
        static std::string meta_type_name(const MetaType* mt);
        
      private:
        Memory::pointer value_;
        Memory::byte buffer_[BUFFER_SIZE];
        bool in_buffer_;
        MetaType* meta_type_;
    };
    
}
 
#ifdef GEO_COMPILER_CLANG
#pragma GCC diagnostic pop
#endif
 
#endif