C++静态类成员变量和成员函数

静态类的功能：
一次构造，共享一个内存空间，且在多个其他类调用不用重复构造

头文件 calculateBufferSize.h

#ifndef CALCULATE_BUFFER_SIZE
#define CALCULATE_BUFFER_SIZE
#include <mutex>
#include <memory>
#include <iostream>
#include <glm/glm.hpp>


class CalculateBufferSize {
    public:
        typedef std::shared_ptr<CalculateBufferSize> Ptr;
        CalculateBufferSize(){
            image_number   = 20;
            image_width    = 1920;
            image_height   = 1080;

            // 计算空间大小bytes,申请内存空间
            image_size     = image_width * image_height * 3ULL; // 单张彩色图大小
            mask_size      = image_width * image_height * 1ULL; // 单张mask图大小
            mask_dt_size       = image_width * image_height * sizeof(float); // 单张mask图大小
            all_images_size    = image_size * image_number;
            all_masks_size     = mask_size * image_number;
            all_masks_dt_size  = mask_dt_size * image_number;
            buffer_size        = all_images_size + all_masks_size + all_masks_dt_size * 2;

            real_KRt44_size        = sizeof(glm::mat4);
            all_real_KRt44_size    = real_KRt44_size * image_number;
            real_Rt44_size         = sizeof(glm::mat4);
            all_real_Rt44_size     = real_Rt44_size * image_number;
            mp_real_K44_size       = sizeof(glm::mat4);
            all_mp_real_K44_size   = mp_real_K44_size * image_number;
            buffer_real_P_size     = all_real_KRt44_size + all_real_Rt44_size + all_mp_real_K44_size;

        };
        ~CalculateBufferSize(){};

        CalculateBufferSize(CalculateBufferSize &) = delete;        // 禁用拷贝构造
        CalculateBufferSize& operator=(const CalculateBufferSize &) = delete;   // 禁用赋值

        static Ptr GetInstance() {
            if(m_CalculateBufferSize == nullptr) {
                std::lock_guard<std::mutex> lk(m_mutex);
                if(m_CalculateBufferSize == nullptr) {
                        m_CalculateBufferSize = std::shared_ptr<CalculateBufferSize>(new CalculateBufferSize());
                }
            }
            std::cout << "CalculateBufferSize类: 引用计数: " << m_CalculateBufferSize.use_count() << std::endl;
            return m_CalculateBufferSize;
        }
        uint64_t image_number;
        uint64_t image_width;
        uint64_t image_height;

        // 计算空间大小bytes,申请内存空间
        uint64_t image_size ; // 单张彩色图大小
        uint64_t mask_size; // 单张mask图大小
        uint64_t mask_dt_size; // 单张mask图大小
        uint64_t all_images_size;
        uint64_t all_masks_size ;
        uint64_t all_masks_dt_size ;
        uint64_t buffer_size   ;

        uint64_t real_KRt44_size  ;
        uint64_t all_real_KRt44_size   ;
        uint64_t real_Rt44_size      ;
        uint64_t all_real_Rt44_size   ;
        uint64_t mp_real_K44_size;
        uint64_t all_mp_real_K44_size;
        uint64_t buffer_real_P_size   ;
private:
    static Ptr m_CalculateBufferSize;
    static std::mutex m_mutex;

};
CalculateBufferSize::Ptr  CalculateBufferSize::m_CalculateBufferSize = nullptr;
std::mutex CalculateBufferSize::m_mutex;

#endif

测试 main.cpp

#include <iostream>
#include "calculateBufferSize.h"

using namespace std;
void testFun(void){
    auto test = CalculateBufferSize::GetInstance();
    std::cout<<"test :buffer_size:"<<test->buffer_size<<std::endl;
    std::cout<<"test :image_number:"<<test->image_number<<std::endl;
    std::cout << "test :CalculateBufferSize内存引用计数: " << test.use_count() << std::endl;
    return;
}

int main(){
    std::cout<<"begin"<<std::endl;
    CalculateBufferSize::Ptr test = CalculateBufferSize::GetInstance();
    std::cout<<"buffer_size:"<<test->buffer_size<<std::endl;
    std::cout<<"image_number:"<<test->image_number<<std::endl;
    cout << "CalculateBufferSize的内存引用计数: " << test.use_count() << endl;
    testFun();
    cout << "CalculateBufferSize的内存引用计数: " << test.use_count() << endl;

    return 0;
}

/*
CalculateBufferSize类: 引用计数: 1
buffer_size:497664000
image_number:20
CalculateBufferSize的内存引用计数: 2
CalculateBufferSize类: 引用计数: 2
test :buffer_size:497664000
test :image_number:20
test :CalculateBufferSize内存引用计数: 3
CalculateBufferSize的内存引用计数: 2

*/

cmake

cmake_minimum_required (VERSION 2.8)
project (template)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/modules/")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
# find the required packages
find_package(GLM REQUIRED)
message(STATUS "GLM included at ${GLM_INCLUDE_DIR}")
include_directories(${CMAKE_SOURCE_DIR}/include)
set (CMAKE_CXX_LINK_EXECUTABLE "${CMAKE_CXX_LINK_EXECUTABLE} -ldl")
add_executable(testStatic testStatic.cpp)