mirror of
https://github.com/boostorg/safe_numerics.git
synced 2026-02-03 09:22:19 +00:00
bce3a5536e
passes all tests adds documentation of library internals implements trap_exception for compile time guarantee for program correctness still needs update to support the above for operations in addition to + and -
44 lines
1.4 KiB
C++
44 lines
1.4 KiB
C++
#include <cassert>
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#include <exception>
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#include <iostream>
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#include <cstdint>
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#include "../include/safe_integer.hpp"
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int main(int argc, const char * argv[]){
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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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// problem: arithmetic operations can yield incorrect results.
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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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// but assert fails to detect it since C++ implicitly
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// converts variables to int before evaluating he expression!
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// assert(z == x + y);
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std::cout << static_cast<int>(z) << " != " << x + y << std::endl;
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std::cout << "error NOT detected!" << std::endl;
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}
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catch(std::exception){
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std::cout << "error detected!" << std::endl;
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}
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// solution: replace std::int8_t with safe<std::int8_t>
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std::cout << "Using safe numerics" << std::endl;
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try{
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using namespace boost::numeric;
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safe<std::int8_t> x = 127;
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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 and invalid result an exception is thrown
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z = x + y;
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}
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catch(std::exception & e){
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// which can catch here
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std::cout << e.what() << std::endl;
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}
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return 0;
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}
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