windows 编码转换

#include <Windows.h>
#include "utility.h"


// wchar_t* 转 char*
int wch2chr(const wchar_t *wBuf, char* &mb_buf)
{
    int nlength= wcslen(wBuf);

    int nbytes = WideCharToMultiByte( 0, 0, wBuf, nlength, NULL, 0, NULL, NULL );

    if( nbytes > 2 * nlength ) nbytes = 2 * nlength;

    mb_buf = new char[nbytes + 1];

    WideCharToMultiByte( 0, 0 , wBuf, nlength, mb_buf, nbytes, NULL, NULL );

    mb_buf[nbytes] = 0;

    return nbytes;
}

// wchar_t* 转 char*
void wch2chr_s(const wchar_t *wBuf, std::string& cstr)
{
    char* mb_buf = NULL;
    int len = wch2chr(wBuf, mb_buf);

    cstr = std::string(mb_buf);
    delete[] mb_buf;
}

// char* 转 wchar_t*
int chr2wch(const char* buffer, wchar_t* &wBuf)
{
    size_t len = strlen(buffer);

    size_t wlen = MultiByteToWideChar(CP_ACP, 0, (const char*)buffer, int(len), NULL, 0);

    wBuf = new wchar_t[wlen + 1];

    MultiByteToWideChar(CP_ACP, 0, (const char*)buffer, int(len), wBuf, int(wlen));
    wBuf[wlen] = 0;

    return (int)wlen;
}

// wchar_t* 转char*
void chr2wch_s(const char* buffer, std::wstring& wcstr)
{
    wchar_t *wbuf = NULL;
    int len = chr2wch(buffer, wbuf);

    wcstr = std::wstring(wbuf);
    delete[] wbuf;
}

//* gbk 转 utf-8
int chr2utf(const char* buf, char* &mb_buf)
{
    WCHAR* wbuf;
    int wlen = chr2wch(buf, wbuf);
    int mb_buf_size = ::WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, NULL, 0, NULL, NULL);
    mb_buf = new char[mb_buf_size + 1];
    int mb_len = ::WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, mb_buf, mb_buf_size, NULL, NULL);
    mb_buf[mb_len] = 0;
    delete[] wbuf;
    return mb_len;
}

// gbk 转 utf-8
void chr2utf_s(const char* buf, std::string& cstr)
{
    char* mb_buf = NULL;
    int len = chr2utf(buf, mb_buf);

    cstr = std::string(mb_buf);
    delete[] mb_buf;
}

// utf-8 转 wchar_t*
int utf2wch(const char* buffer, wchar_t* &wBuf)
{
    size_t len = strlen(buffer);

    size_t wlen = MultiByteToWideChar(CP_UTF8, 0, (const char*)buffer, int(len), NULL, 0);

    wBuf = new wchar_t[wlen + 1];

    MultiByteToWideChar(CP_UTF8, 0, (const char*)buffer, int(len), wBuf, int(wlen));
    wBuf[wlen] = 0;

    return (int)wlen;
}

// utf-8 转  wchar_t*
void utf2wch_s(const char* buffer, std::wstring& wcstr)
{
    wchar_t* wbuf = NULL;
    int len = utf2wch(buffer, wbuf);

    wcstr = std::wstring(wbuf);
    delete[] wbuf;
}

// utf-8 转 gbk
int utf2chr(const char* buf, char* &mb_buf)
{
    WCHAR* wbuf;
    int wlen = utf2wch(buf, wbuf);
    int mb_buf_size = ::WideCharToMultiByte(CP_ACP, 0, wbuf, wlen, NULL, 0, NULL, NULL);
    mb_buf = new char[mb_buf_size + 1];
    int mb_len = ::WideCharToMultiByte(CP_ACP, 0, wbuf, wlen, mb_buf, mb_buf_size, NULL, NULL);
    mb_buf[mb_len] = 0;
    delete[] wbuf;
    return mb_len;
}

// utf8 转 gbk
void utf2chr_s(const char* buf, std::string& cstr)
{
    char* mb_buf = NULL;
    int len = utf2chr(buf, mb_buf);

    cstr = std::string(mb_buf);
    delete[] mb_buf;
}