stl-data-impl.cpp

#include <stdio.h>
#include <string>
#include <map>
#include <vector>
#include <list>

void ds_str_i(void *p) {
    char **raw = (char**)p;
    char *s = *raw;
    size_t len = *(size_t*)(s - sizeof(size_t) * 3);
    printf("str: %s (%zd)\n", s, len);
}

size_t ds_str() {
    std::string s = "hello";
    ds_str_i(&s);
    return s.size();
}

template <typename T>
void ds_vec_i(void *p) {
    T *start = *(T**)p;
    T *finish = *(T**)((char*)p + sizeof(void*));
    T *end_storage = *(T**)((char*)p + 2 * sizeof(void*));
    printf("vec size: %ld, avaiable size: %ld\n", finish - start, end_storage - start); 
}

size_t ds_vec() {
    std::vector<int> vec;
    vec.push_back(0x11);
    vec.push_back(0x22);
    vec.push_back(0x33);
    ds_vec_i<int>(&vec);
    return vec.size();
}

size_t ds_map() {
    std::map<std::string, int> imap;
    imap["abc"] = 0xbbb;
    return imap.size();
}

#define NEXT(ptr, T) do { \
    void *n = *(char**)ptr; \
    T val = *(T*)((char**)ptr + 2); \
    printf("list item %p val: 0x%x\n", ptr, val); \
    ptr = n; \
} while (0)

template <typename T>
void ds_list_i(void *p) {
    void *ptr = *(char**)p;

    NEXT(ptr, T);
    NEXT(ptr, T);
    NEXT(ptr, T);
}

size_t ds_list() {
    std::list<int> lst;
    lst.push_back(0x11);
    lst.push_back(0x22);
    lst.push_back(0x33);
    ds_list_i<int>(&lst);
    return lst.size();
}

int main()
{
    ds_str();
    ds_map();
    ds_vec();
    ds_list();
    return 0;
}