code

/*
* c++17 std::any
*/#include <cstdint>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <thread>
#include <chrono>namespace lxz {// T不为指针时
template<typename T>
struct Data {Data(): data_(nullptr), cnt_(1){ }Data(const T data) {data_ = new T(data);}~Data(){if (data_) {delete data_;data_ = nullptr;}}T& Get(void) {return *data_;}T* data_;uint32_t cnt_;
};
// T为char*时
template<>
struct Data<char*> {Data(): data_(nullptr), cnt_(1){ }Data(const char* data) {cnt_ = strlen(data);data_ = (char*)(malloc(cnt_));(void)memcpy(data_, data, cnt_);}~Data(){if (data_) {free(data_);data_ = nullptr;}}char* Get(void) const {return data_;}char* data_;uint32_t cnt_;
};
// T为int*时
template<>
struct Data<int*> {Data(): data_(nullptr), cnt_(1){ }Data(const int* data) {cnt_ = strlen((const char*)data) / 4;data_ = (int*)malloc(cnt_ * 4);(void)memcpy(data_, data, cnt_ * 4);}~Data(){if (data_) {free(data_);data_ = nullptr;}}int* Get(void) const {return data_;}int* data_;uint32_t cnt_;
};class any
{
public:any() :data_(nullptr){}~any() {if (data_) {delete data_;data_ = nullptr;}}template<typename T>any& operator=(const T data) {if (data_) {delete data_;}data_ = new Data<T>(data);return *this;}void* Get(void) const {return data_;}
private:void* data_;
};template<typename T>
T& any_cast(any& obj)
{return ((Data<T>*)(obj.Get()))->Get();
}}void lxz_any_test(void) {lxz::any x;char c = 'c';int val = 100;const char* str = "hello world!";while (1) {x = c;std::cout << lxz::any_cast<char>(x) << std::endl;x = val;std::cout << lxz::any_cast<int>(x) << std::endl;x = str;std::cout << lxz::any_cast<const char*>(x) << std::endl;std::this_thread::sleep_for(std::chrono::milliseconds(100));}}

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