C++ Mathematical Expression Library (ExprTk) https://www.partow.net/programming/exprtk/index.html

exprtk_simple_example_20.cpp

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+/*
+ **************************************************************
+ *         C++ Mathematical Expression Toolkit Library        *
+ *                                                            *
+ * Simple Example 20                                          *
+ * 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 <cstdio>
+#include <stdexcept>
+#include <map>
+#include <string>
+
+#include "exprtk.hpp"
+
+
+struct vector_access_rtc : public exprtk::vector_access_runtime_check
+{
+   typedef std::map<void*, std::string> map_t;
+   map_t vector_map;
+
+   bool handle_runtime_violation(violation_context& context)
+   {
+      const map_t::iterator itr     = vector_map.find(static_cast<void*>(context.base_ptr));
+      const std::string vector_name = (itr != vector_map.end()) ?
+                                      itr->second : "Unknown"   ;
+
+      printf("Runtime vector access violation\n"
+             "Vector: %s base: %p end: %p access: %p typesize: %d\n",
+             vector_name.c_str(),
+             context.base_ptr   ,
+             context.end_ptr    ,
+             context.access_ptr ,
+             static_cast<unsigned int>(context.type_size));
+
+      throw std::runtime_error
+         ("Runtime vector access violation. Vector: " + vector_name);
+
+      return false;
+   }
+};
+
+template <typename T>
+void vector_overflow_example()
+{
+   typedef exprtk::symbol_table<T> symbol_table_t;
+   typedef exprtk::expression<T>   expression_t;
+   typedef exprtk::parser<T>       parser_t;
+
+   const std::string expression_str =
+      " for (var i := 0; i < max(v0[],v1[]); i += 1) "
+      " {                                            "
+      "    v0[i] := (2 * v0[i]) + (v1[i] / 3);       "
+      " }                                            ";
+
+   T v0[5 ] = { 0, 1, 2, 3, 4 };
+   T v1[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+
+   vector_access_rtc vec_rtc;
+
+   vec_rtc.vector_map[v0] = "v0";
+   vec_rtc.vector_map[v1] = "v1";
+
+   symbol_table_t symbol_table;
+   expression_t   expression;
+   parser_t       parser;
+
+   symbol_table.add_vector("v0", v0);
+   symbol_table.add_vector("v1", v1);
+
+   expression.register_symbol_table(symbol_table);
+
+   parser.register_vector_access_runtime_check(vec_rtc);
+
+   if (!parser.compile(expression_str, expression))
+   {
+      printf("Error: %s\tExpression: %s\n",
+             parser.error().c_str(),
+             expression_str.c_str());
+
+      return;
+   }
+
+   try
+   {
+      expression.value();
+   }
+   catch(std::runtime_error& exception)
+   {
+      printf("Exception: %s\n",exception.what());
+   }
+}
+
+int main()
+{
+   vector_overflow_example<double>();
+   return 0;
+}