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/* ************************************************************** * C++ Mathematical Expression Toolkit Library * * * * ExprTk Compilation Timeout Check * * Author: Arash Partow (1999-2024) * * URL: https://www.partow.net/programming/exprtk/index.html * * * * Copyright notice: * * Free use of the Mathematical Expression Toolkit Library is * * permitted under the guidelines and in accordance with the * * most current version of the MIT License. * * https://www.opensource.org/licenses/MIT * * SPDX-License-Identifier: MIT * * * ************************************************************** */ #include #include #include #include "exprtk.hpp" struct compilation_timeout_check final : public exprtk::compilation_check { static constexpr std::size_t max_iters_per_check = 10000; bool continue_compilation(compilation_context& context) override { if (++iterations_ >= max_iters_per_check) { if (std::chrono::steady_clock::now() >= timeout_tp_) { context.error_message = "Compilation has timed-out"; return false; } iterations_ = 0; } return true; } using time_point_t = std::chrono::time_point; void set_timeout_time(const time_point_t& timeout_tp) { timeout_tp_ = timeout_tp; } std::size_t iterations_ = max_iters_per_check; time_point_t timeout_tp_; }; template void compilation_timeout_check_example() { typedef exprtk::symbol_table symbol_table_t; typedef exprtk::expression expression_t; typedef exprtk::parser parser_t; const std::string base_expression_string = "x := " "((1 /1) * sin( 2 * pi * f * t) + (1 /3) * sin( 6 * pi * f * t)+" " (1 /5) * sin(10 * pi * f * t) + (1 /7) * sin(14 * pi * f * t)+" " (1 /9) * sin(18 * pi * f * t) + (1/11) * sin(22 * pi * f * t)+" " (1/13) * sin(26 * pi * f * t) + (1/15) * sin(30 * pi * f * t)+" " (1/17) * sin(34 * pi * f * t) + (1/19) * sin(38 * pi * f * t)+" " (1/21) * sin(42 * pi * f * t) + (1/23) * sin(46 * pi * f * t)+" " (1/25) * sin(50 * pi * f * t) + (1/27) * sin(54 * pi * f * t));"; std::string large_expression_string = "var x := 0;"; for (std::size_t i = 0; i < 60000; ++i) { large_expression_string += base_expression_string; } static const T pi = T(3.141592653589793238462643383279502); const T f = pi / T(10); const T a = T(10); T t = T(0); symbol_table_t symbol_table; symbol_table.add_variable("t",t); symbol_table.add_constant("f",f); symbol_table.add_constant("a",a); symbol_table.add_constants(); expression_t expression; expression.register_symbol_table(symbol_table); compilation_timeout_check compilation_timeout_chck; parser_t parser; parser.register_compilation_timeout_check(compilation_timeout_chck); const auto max_duration = std::chrono::seconds(8); const auto timeout_tp = std::chrono::steady_clock::now() + max_duration; compilation_timeout_chck.set_timeout_time(timeout_tp); if (!parser.compile(large_expression_string, expression)) { printf("Error: %s\t\n", parser.error().c_str()); return; } } int main() { compilation_timeout_check_example(); return 0; }