C++类型转换(无精度降低)

#include <cassert>

/**

* Cast one size of int down to another one.

* Asserts that no precision is lost at runtime.

*/

template<typename Small, typename Large>

inline Small

downCast(const Large& large)

{

Small small = static_cast<Small>(large);

// The following comparison (rather than "large==small") allows

// this method to convert between signed and unsigned values.

assert(large-small == 0);

return small;

}

 

节选自 https://github.com/PlatformLab/NanoLog.git

中 "common.h" 文件.