Conversion of UTF-8 char * to CString

Question

How do I convert a string in UTF-8 char* to CString?

Serge Dundich · Accepted Answer · 2011-04-15T07:40:32.463

bool Utf8ToCString( CString& cstr, const char* utf8Str )
{
    size_t utf8StrLen = strlen(utf8Str);

    if( utf8StrLen == 0 )
    {
        cstr.Empty();
        return true;
    }

    LPTSTR* ptr = cstr.GetBuffer(utf8StrLen+1);

#ifdef UNICODE
    // CString is UNICODE string so we decode
    int newLen = MultiByteToWideChar(
                     CP_UTF8,  0,
                     utf8Str, utf8StrLen,  ptr, utf8StrLen+1
                     );
    if( !newLen )
    {
        cstr.ReleaseBuffer(0);
        return false;
    }
#else
    WCHAR* buf = (WCHAR*)malloc(utf8StrLen);

    if( buf == NULL )
    {
        cstr.ReleaseBuffer(0);
        return false;
    }

    int newLen = MultiByteToWideChar(
                     CP_UTF8,  0,
                     utf8Str, utf8StrLen,  buf, utf8StrLen
                     );
    if( !newLen )
    {
        free(buf);
        cstr.ReleaseBuffer(0);
        return false;
    }

    assert( newLen < utf8StrLen );
    newLen = WideCharToMultiByte(
                     CP_ACP,  0,
                     buf, newLen,  ptr, utf8StrLen
                     );
    if( !newLen )
    {
        free(buf);
        cstr.ReleaseBuffer(0);
        return false;
    }

    free(buf);
#endif

    cstr.ReleaseBuffer(newLen);
    return true;
}

Though this function is valid for both UNICODE and non-UNICODE configurations IMHO using UNICODE configuration in Win32 programs is much more productive (in general and in this function).

this is not a solution. The solution is to figure out the target single-byte code page and to convert UTF-8 string to single-byte string of that CP. — Jurlie, Apr 15 '11 at 07:13
@Jurlie: read the comment before memcpy. Though may be I'll post implementation now. — Serge Dundich, Apr 15 '11 at 07:16
Edited the post to include UTF8 to current 8-bit code page conversion. — Serge Dundich, Apr 15 '11 at 07:28

score 4 · Answer 2 · answered Apr 15 '11 at 06:45

4

Call MultiByteToWideChar with a code page of CP_UTF8, then use CString as normal.

answered Apr 15 '11 at 06:45

ildjarn

62,044
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I want it to be converted to char* not wchar_t *.. Is there any method? – Greenhorn Apr 15 '11 at 06:49
1

@Athreya : Why on earth would you want that? That conversion is bound to be lossy -- if the string was Unicode to begin with, what makes you think it contains exclusively ANSI characters? – ildjarn Apr 15 '11 at 06:53
I need to parse and execute the statement using OCI library which only accepts char* as input – Greenhorn Apr 15 '11 at 06:54
3

@Athreya : Isn't `char*` what you already have? In any case, I'm not aware of any "MultiByteToMultiByte" sort of function, so I think you'll have to round-trip it -- call `MultiByteToWideChar` with `CP_UTF8` then `WideCharToMultiByte` with whatever code page you want the resulting `char*` in. – ildjarn Apr 15 '11 at 06:56

score 0 · Answer 3 · answered Apr 15 '11 at 07:03

0

If your string contains only ASCII-characters with codes 0 to 127 you may threat your UTF-8 string as ASCII string and initialise CString with it:

CString my_cstr((char*)my_string);

Otherwise (if your UTF-8 string contains some other characters) you have no easy way to get char* string from it.

answered Apr 15 '11 at 07:03

Jurlie

1,014
10
27

I've got other characters in the UTF-8 string – Greenhorn Apr 15 '11 at 07:04
@Athreya what is codepage you want to convert your string to? Or what is the language at least? Are you sure your UTF-8 string could be represented as single-byte string at all? – Jurlie Apr 15 '11 at 07:15
@Athreya : Jurlie means *losslessly* represented as a single-byte string. And your first comment on this answer indicates that this isn't the case. – ildjarn Apr 15 '11 at 07:23
I meant the language of string to convert, not a programming language :-D – Jurlie Apr 15 '11 at 07:24
@Julie the string is Japanese – Greenhorn Apr 15 '11 at 07:35

Conversion of UTF-8 char * to CString

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