43 lines
1.3 KiB
C++
43 lines
1.3 KiB
C++
// Copyright (c) 2018 Robert Ramey
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// 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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#include <iostream>
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#include <boost/safe_numerics/safe_integer.hpp>
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int main(int, const char *[]){
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std::cout << "example 1:";
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std::cout << "undetected erroneous expression evaluation" << std::endl;
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std::cout << "Not using safe numerics" << std::endl;
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try{
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std::int8_t x = 127;
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std::int8_t y = 2;
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std::int8_t z;
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// this produces an invalid result !
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z = x + y;
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std::cout << "error NOT detected!" << std::endl;
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std::cout << (int)z << " != " << (int)x << " + " << (int)y << std::endl;
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}
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catch(const std::exception &){
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std::cout << "error detected!" << std::endl;
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}
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// solution: replace int with safe<int>
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std::cout << "Using safe numerics" << std::endl;
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try{
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using namespace boost::safe_numerics;
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safe<std::int8_t> x = INT_MAX;
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safe<std::int8_t> y = 2;
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safe<std::int8_t> z;
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// rather than producing an invalid result an exception is thrown
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z = x + y;
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}
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catch(const std::exception & e){
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// which we can catch here
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std::cout << "error detected:" << e.what() << std::endl;
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}
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return 0;
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}
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