font_cache.cpp

/* This file is part of the "ST" project.
 * You may use, distribute or modify this code under the terms
 * of the GNU General Public License version 2.
 * See LICENCE.txt in the root directory of the project.
 *
 * Author: Maxim Atanasov
 * E-mail: maxim.atanasov@protonmail.com
 */
 
#include "font_cache.hpp"
 
static uint32_t entries = 0;
static cache_list cache;
static cache_hash hash;
static uint32_t cache_size = 0;
 
void ST::renderer_sdl::font_cache::move_to_front(std::list<key_pair> &list, std::list<key_pair>::iterator element) {
    if (element != list.begin()) {
        list.splice(list.begin(), list, element, std::next(element));
    }
}
 
void ST::renderer_sdl::font_cache::set_max(uint32_t max) {
    cache_size = max;
}
 
SDL_Texture *ST::renderer_sdl::font_cache::get_cached_string(const std::string &str, uint16_t font) {
    font_cache_tuple temp = std::make_tuple(str, font);
    if (hash.find(temp) != hash.end()) {
        move_to_front(cache, hash[temp]);
        return hash.at(temp)->second;;
    }
    return nullptr;
}
 
void ST::renderer_sdl::font_cache::cache_string(const std::string &str, SDL_Texture *texture, uint16_t font) {
    font_cache_tuple temp = std::make_tuple(str, font);
    cache.push_front(std::make_pair(temp, texture));
    hash[temp] = cache.begin();
    entries++;
    if (entries > cache_size) {
        hash.erase(cache.back().first);
        SDL_DestroyTexture(cache.back().second);
        cache.pop_back();
        entries--;
    }
}
 
void ST::renderer_sdl::font_cache::close() {
    for (auto &i: cache) {
        SDL_DestroyTexture(i.second);
    }
}
 
void ST::renderer_sdl::font_cache::clear() {
    cache.clear();
    hash.clear();
}