wstring <=> string convert utils

wstring2string.cpp

#include<cassert>
#include<cstdio>
#include<string>
#include<map>
using namespace std;

std::wstring string2wstring(const std::string& s)
{
    int len;
    int slength = (int)s.length() + 1;
    len = MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, 0, 0);
    wchar_t* buf = new wchar_t[len];
    MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, buf, len);
    std::wstring r(buf);
    delete[] buf;
    return r;
}

std::string wstring2string(const std::wstring& s)
{
    int len;
    int slength = (int)s.length() + 1;
    len = WideCharToMultiByte(CP_ACP, 0, s.c_str(), slength, 0, 0, NULL, NULL);
    char* buf = new char[len];
    WideCharToMultiByte(CP_ACP, 0, s.c_str(), slength, buf, len, NULL, NULL);
    std::string r(buf);
    delete[] buf;
    return r;
}