【C/C++】字符串编码转换【Windows版】

StrConv.h

#pragma once
#include <string>
       
#ifdef _UNICODE

#ifndef tchar
#define tchar wchar_t
#endif
#ifndef tstring
#define tstring std::wstring
#endif

#else

#ifndef tchar
#define tchar char
#endif
#ifndef tstring
#define tstring std::string
#endif

#endif    // _UNICODE

//////////////////////////////////////////////////////////////////////////
// ANSI <-> UTF8 <-> UTF16
//////////////////////////////////////////////////////////////////////////
std::wstring AnsiToUtf16(const std::string& str);
std::string Utf16toUtf8(const std::wstring& str);
std::string AnsiToUtf8(const std::string& str);

std::string TStrToUtf8(const tstring& str);

std::wstring Utf8ToUtf16(const std::string& str);
std::string Utf16ToAnsi(const std::wstring& str);
std::string Utf8ToAnsi(const std::string& str);

tstring Utf8ToTStr(const std::string& str);

#ifdef _UNICODE
#define TStrToAnsi(str) Utf16ToAnsi(str)
#define TStrToUtf16(str) (str)

#define AnsiToTStr(str) AnsiToUtf16(str)
#define Utf16ToTStr(str) (str)
#else
#define TStrToAnsi(str) (str)
#define TStrToUtf16(str) AnsiToUtf16(str)

#define AnsiToTStr(str) (str)
#define Utf16ToTStr(str) Utf16ToAnsi(str)
#endif

StrConv.cpp

#include "StrConv.h"
#include <windows.h>

std::wstring AnsiToUtf16(const std::string& str)
{
    std::wstring res;
    int bufferSize = MultiByteToWideChar(CP_ACP, 0, str.c_str(), (int)str.size() + 1, NULL, 0);
    if (bufferSize)
    {
        wchar_t* buffer = new wchar_t[bufferSize];
        if (MultiByteToWideChar(CP_ACP, 0, str.c_str(), (int)str.size() + 1, buffer, bufferSize))
            res = buffer;
        delete[] buffer;
        buffer = NULL;
    }

    return res;
}

std::string Utf16toUtf8(const std::wstring& str)
{
    std::string res;
    int bufferSize = WideCharToMultiByte(CP_UTF8, 0, str.c_str(), (int)str.size() + 1, NULL, 0, NULL, NULL);
    if (bufferSize)
    {
        char* buffer = new char[bufferSize];
        if (WideCharToMultiByte(CP_UTF8, 0, str.c_str(), (int)str.size() + 1, buffer, bufferSize, NULL, NULL))
            res = buffer;
        delete[] buffer;
        buffer = NULL;
    }

    return res;
}

std::string AnsiToUtf8(const std::string& str)
{
    return Utf16toUtf8(AnsiToUtf16(str));
}

std::string TStrToUtf8(const tstring& str)
{
#ifdef _UNICODE
    return Utf16toUtf8(str);
#else
    return AnsiToUtf8(str);
#endif
}

std::wstring Utf8ToUtf16(const std::string& str)
{
    std::wstring res;
    int bufferSize = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), (int)str.size() + 1, NULL, 0);
    if (bufferSize)
    {
        wchar_t* buffer = new wchar_t[bufferSize];
        if (MultiByteToWideChar(CP_UTF8, 0, str.c_str(), (int)str.size() + 1, buffer, bufferSize))
            res = buffer;
        delete[] buffer;
        buffer = NULL;
    }

    return res;
}

std::string Utf16ToAnsi(const std::wstring& str)
{
    std::string res;
    int bufferSize = WideCharToMultiByte(CP_ACP, 0, str.c_str(), (int)str.size() + 1, NULL, 0, NULL, NULL);
    if (bufferSize)
    {
        char* buffer = new char[bufferSize];
        if (WideCharToMultiByte(CP_ACP, 0, str.c_str(), (int)str.size() + 1, buffer, bufferSize, NULL, NULL))
            res = buffer;
        delete[] buffer;
        buffer = NULL;
    }

    return res;
}

std::string Utf8ToAnsi(const std::string& str)
{
    return Utf16ToAnsi(Utf8ToUtf16(str));
}

tstring Utf8ToTStr(const std::string& str)
{
#ifdef _UNICODE
    return Utf8ToUtf16(str);
#else
    return Utf8ToAnsi(str);
#endif
}