位集作为函数的返回值 [英] Bitset as the return value of a function

问题描述

我想要一个接口，该接口的函数返回一个位集:

I'd like to have an interface whose function returns a bitset:

class IMyInterface
{
public:
    virtual std::bitset<100> GetBits() = 0;
};

问题是我不想强制bitset的大小.所以我认为我必须改用boost::dynamic_bitset:

The problem is that I don't want to force the size of the bitset. So I think I have to use boost::dynamic_bitset instead:

class IMyInterface
{
public:
    virtual boost::dynamic_bitset<> GetBits() = 0;
};

我听说boost::dynamic_bitset比std::bitset慢.还有其他方法可以避免使用dynamic_bitset并具有一个返回std::bitset且其大小由实现者确定的接口吗?

I have heard that boost::dynamic_bitset is slower than std::bitset though. Is there any other way to avoid using dynamic_bitset and have an interface that returns a std::bitset whose size is determined by the implementors?

推荐答案

首先，由于其静态性，std::bitset

First of all, due to its static-ness, std::bitset is not considered to be a good solution. Apart from boost:: stuff, you may use things like...

template<size_t N>
class IMyInterface {
    public:
        virtual std::bitset<N> GetBits() = 0;
};

但是那仍然太静态了，不是吗?好吧，标准指定了std::vector<bool> 的专业化，即通常实现为动态的，内存有效的std::bitset！所以...

But that would still be too static, no? Well, the standards specify that there's an specialization of std::vector<bool>, that is usually implemented as a dynamic, memory-efficient std::bitset! So...

#include <vector>

class IMyInterface {
    public:
        virtual std::vector<bool>& GetBits() = 0;
};

编辑:为提高效率而制作的IMyInterface::GetBits()返回参考.

Edit: Made IMyInterface::GetBits() return a reference for efficiency purposes.

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