100 lines
2.3 KiB
C++
100 lines
2.3 KiB
C++
/* Boost.Flyweight example of use of key-value flyweights.
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*
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* Copyright 2006-2008 Joaquin M Lopez Munoz.
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* See http://www.boost.org/libs/flyweight for library home page.
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*/
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#include <boost/array.hpp>
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#include <boost/flyweight.hpp>
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#include <boost/flyweight/key_value.hpp>
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#include <cstdlib>
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#include <iostream>
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#include <string>
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#include <vector>
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using namespace boost::flyweights;
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/* A class simulating a texture resource loaded from file */
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class texture
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{
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public:
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texture(const std::string& filename):filename(filename)
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{
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std::cout<<"loaded "<<filename<<" file"<<std::endl;
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}
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texture(const texture& x):filename(x.filename)
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{
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std::cout<<"texture["<<filename<<"] copied"<<std::endl;
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}
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~texture()
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{
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std::cout<<"unloaded "<<filename<<std::endl;
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}
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const std::string& get_filename()const{return filename;}
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// rest of the interface
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private:
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std::string filename;
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};
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/* key extractor of filename strings from textures */
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struct texture_filename_extractor
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{
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const std::string& operator()(const texture& x)const
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{
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return x.get_filename();
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}
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};
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/* texture flyweight */
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typedef flyweight<
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key_value<std::string,texture,texture_filename_extractor>
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> texture_flyweight;
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int main()
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{
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/* texture filenames */
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const char* texture_filenames[]={
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"grass.texture","sand.texture","water.texture","wood.texture",
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"granite.texture","cotton.texture","concrete.texture","carpet.texture"
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};
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const int num_texture_filenames=
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sizeof(texture_filenames)/sizeof(texture_filenames[0]);
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/* create a massive vector of textures */
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std::cout<<"creating flyweights...\n"<<std::endl;
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std::vector<texture_flyweight> textures;
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for(int i=0;i<50000;++i){
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textures.push_back(
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texture_flyweight(texture_filenames[std::rand()%num_texture_filenames]));
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}
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/* Just for the sake of making use of the key extractor,
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* assign some flyweights with texture objects rather than strings.
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*/
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for(int j=0;j<50000;++j){
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textures.push_back(
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texture_flyweight(
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textures[std::rand()%textures.size()].get()));
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}
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std::cout<<"\n"<<textures.size()<<" flyweights created\n"<<std::endl;
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return 0;
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}
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