Question

我编写了一段代码，该代码在内部使用C ++ STL（std :: vector）存储一些信息，然后通过类似于C的函数提供该信息，稍后将在Windows DLL中将其导出。我想知道这种方式是否正确和稳定。如果在该领域有一定经验的人可以向我确认没问题或向我指出问题，将不胜感激。这只是一个示例示例，所有错误处理功能将在以后添加。

#include <iostream>
#include <string>
#include <vector>

typedef struct _c_vector_wrapper_config
{
    size_t currentPosition = -1;
    // for std::string
    std::vector<std::string> *vPointer = nullptr;
    std::vector<std::string>::iterator vIterator;

    // for C null terminated string 
    // we support 2 type of vectors to have ability to work with C like strings from other than C++
    // languages 
    // Also we allocate memory for this string using C runtime malloc and at the end we can easily free 
    // this memory to avoid memory leaks.

    // Why we use also std::vector<std::string> ? Because STL string operation is more simple and safe
    // and we need C like strings only to export them from DLL
    std::vector<char*> *vPointerChar = nullptr;
    std::vector<char*>::iterator vIteratorChar;

} c_vector_wrapper_config;



c_vector_wrapper_config *vector_wrapper_config = new c_vector_wrapper_config();

// c_vector_wrapper_config *vector_wrapper_config = new c_vector_wrapper_config();



void create_vector();
void delete_vector();
void add_value(std::string value);
char* get_value();


int main(void)
{

    create_vector();

    add_value("test1");
    add_value("test2");
    add_value("test3");

    std::cout << get_value() << std::endl;
    std::cout << get_value() << std::endl;

    delete_vector();

    return 0;
}

void create_vector()
{
    if (vector_wrapper_config->vPointer == nullptr)
    {
        vector_wrapper_config->vPointer = new std::vector<std::string>();
        vector_wrapper_config->vPointerChar = new std::vector<char*>();
    }

}

void add_value(std::string value)
{
    vector_wrapper_config->vPointer->push_back(value);

    std::size_t str_length = value.size();
    char *c_string = static_cast<char*>(malloc(str_length +1));
    value.copy(c_string, str_length, 0);
    c_string[str_length] = '\0';

    vector_wrapper_config->vPointerChar->push_back(c_string);
}

char* get_value()
{
    vector_wrapper_config->currentPosition++;
    char* current_value =  (*vector_wrapper_config->vPointerChar)[vector_wrapper_config->currentPosition];

    return current_value;
}

void delete_vector()
{
    delete vector_wrapper_config->vPointer;

    // free memory allocated previously for C like strings
    for (std::vector<char*>::iterator it = vector_wrapper_config->vPointerChar->begin(); it != vector_wrapper_config->vPointerChar->end(); ++it)
    {
        free(*it);
    }
}

导出STL std :: vector功能槽DLL

0 个答案: