Widechartomultibyte and multibytetowidechar Functions

To support Unicode encoding, mutual conversion between multiple bytes and wide bytes is required. When using these two system functions, You need to specify the code page, encounter garbled characters in the actual application process, and then re-read "Windows core programming" to summarize the correct usage.
The widechartomultibyte code page is used to mark the code page related to the newly converted string.
The code page of multibytetowidechar is used to mark the code page related to a multi-byte string.
The common code pages are cp_acp and cp_utf8.
The cp_acp code page is used to convert ANSI to Unicode.
The cp_utf8 code page is used to realize the conversion between the UTF-8 and Unicode.
The following is code implementation:
1. ANSI to Unicode
Wstring ansitounicode (const string & Str)
{
Int Len = 0;
Len = Str. Length ();
Int unicodelen =: multibytetowidechar (cp_acp,
0,
Str. c_str (),
-1,
Null,
0 );
Wchar_t * punicode;
Punicode = new wchar_t [unicodelen + 1];
Memset (punicode, 0, (unicodelen + 1) * sizeof (wchar_t ));
: Multibytetowidechar (cp_acp,
0,
Str. c_str (),
-1,
(Lpwstr) punicode,
Unicodelen );
Wstring RT;
RT = (wchar_t *) punicode;
Delete punicode;
 
Return RT;
}
2. Unicode to ANSI
String unicodetoansi (const wstring & Str)
{
Char * pelementtext;
Int itextlen;
// Wide Char to multi char
Itextlen = widechartomultibyte (cp_acp,
0,
Str. c_str (),
-1,
Null,
0,
Null,
Null );
Pelementtext = new char [itextlen + 1];
Memset (void *) pelementtext, 0, sizeof (char) * (itextlen + 1 ));
: Widechartomultibyte (cp_acp,
0,
Str. c_str (),
-1,
Pelementtext,
Itextlen,
Null,
Null );
String strtext;
Strtext = pelementtext;
Delete [] pelementtext;
Return strtext;
}
3. UTF-8 to Unicode
Wstring utf8tounicode (const string & Str)
{
Int Len = 0;
Len = Str. Length ();
Int unicodelen =: multibytetowidechar (cp_utf8,
0,
Str. c_str (),
-1,
Null,
0 );
Wchar_t * punicode;
Punicode = new wchar_t [unicodelen + 1];
Memset (punicode, 0, (unicodelen + 1) * sizeof (wchar_t ));
: Multibytetowidechar (cp_utf8,
0,
Str. c_str (),
-1,
(Lpwstr) punicode,
Unicodelen );
Wstring RT;
RT = (wchar_t *) punicode;
Delete punicode;
 
Return RT;
}
4. Unicode to UTF-8
String unicodetoutf8 (const wstring & Str)
{
Char * pelementtext;
Int itextlen;
// Wide Char to multi char
Itextlen = widechartomultibyte (cp_utf8,
0,
Str. c_str (),
-1,
Null,
0,
Null,
Null );
Pelementtext = new char [itextlen + 1];
Memset (void *) pelementtext, 0, sizeof (char) * (itextlen + 1 ));
: Widechartomultibyte (cp_utf8,
0,
Str. c_str (),
-1,
Pelementtext,
Itextlen,
Null,
Null );
String strtext;
Strtext = pelementtext;
Delete [] pelementtext;
Return strtext;
}