Tokenizer_exprtk.hpp

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/*
 *  This file is part of AQUAgpusph, a free CFD program based on SPH.
 *  Copyright (C) 2012  Jose Luis Cercos Pita <jl.cercos@upm.es>
 *
 *  AQUAgpusph 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  AQUAgpusph 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 AQUAgpusph.  If not, see <http://www.gnu.org/licenses/>.
 */

 
#ifndef TOKENIZER_H_INCLUDED
#define TOKENIZER_H_INCLUDED
 
#include <map>
#include <string>
#include <mutex>
#include <typeinfo>
#include <iostream>
#include "aquagpusph/ext/exprtk.hpp"
#include "aquagpusph/InputOutput/Logger.hpp"
#include "aquagpusph/AuxiliarMethods.hpp"
 
namespace Aqua {
 
typedef long double tokenizer_t;

class DECLDIR Tokenizer_exprtk
{
  public:
        Tokenizer_exprtk();

        ~Tokenizer_exprtk();

        template<typename T>
        void registerVariable(const std::string name, T value)
        {
                tokenizer_t val = narrow_cast<tokenizer_t>(value);
                const std::lock_guard<std::mutex> lock(this->mutex);
                removeVariable(name);
                vars.add_variable(name, val);
        }

        std::vector<std::string> exprVariables(const std::string eq);

        template<typename T=float>
        T solve(const std::string eq)
        {
                const std::lock_guard<std::mutex> lock(this->mutex);
                exprtk::parser<tokenizer_t> parser;
                exprtk::expression<tokenizer_t> expr;
 
                // First try straight number conversions
                T res = 0;
                size_t sz;
                try {
                        res = narrow_cast<T>((int64_t)std::stoll(eq, &sz));
                        if (sz == eq.size()) {
                                return res;
                        }
                } catch (...) {
                }
                try {
                        std::string::size_type sz;
                        res = narrow_cast<T>(std::stod(eq, &sz));
                        if (sz == eq.size()) {
                                return res;
                        }
                } catch (...) {
                }
 
                expr.register_symbol_table(vars);
                // expr.register_symbol_table(ivars);
 
                if (!parser.compile(eq, expr))
                {
                        LOG(L_ERROR, std::string("Error parsing \"") + eq + "\":\n");
                        LOG0(L_DEBUG, "\n");
                        LOG0(L_DEBUG, parser.error() + "\n");
                        LOG0(L_DEBUG, "\n");
                        throw std::runtime_error("Invalid expression");
                }
 
                tokenizer_t res_org;
                try {
                        res_org = expr.value();
                        res = narrow_cast<T>(res_org);
                } catch(std::out_of_range) {
                        LOG(L_ERROR, std::string("Error parsing \"") + eq + "\":\n");
                        LOG0(L_DEBUG, "\n");
                        LOG0(L_DEBUG, std::string("The result ") +
                             std::to_string(res_org) + " overflows the type \"" +
                             typeid(res).name() + "\"\n");
                        LOG0(L_DEBUG, "\n");
                        throw;
                }
                return res;
        }
 
  protected:
        inline void removeVariable(const std::string name)
        {
                if (vars.is_variable(name))
                        vars.remove_variable(name);
        }
 
  private:
        exprtk::symbol_table<tokenizer_t> vars;

        static std::mutex mutex;
}; // class Tokenizer
 
} // Aqua::
 
#endif // TOKENIZER_H_INCLUDED