win32: convert between wchar and utf8

win32_utf8.c

wchar_t*
fromUTF8(
    const char* src,
    size_t src_length,  /* = 0 */
    size_t* out_length  /* = NULL */
    )
{
	if(!src)
		{ return NULL; }

	if(src_length == 0) { src_length = strlen(src); }
	int length = MultiByteToWideChar(CP_UTF8, 0, src, src_length, 0, 0);
	wchar_t *output_buffer = (wchar_t*)malloc((length+1) * sizeof(wchar_t));
	if(output_buffer) {
		MultiByteToWideChar(CP_UTF8, 0, src, src_length, output_buffer, length);
		output_buffer[length] = L'\0';
	}
    if(out_length) { *out_length = length; }
	return output_buffer;
}

char*
toUTF8(
    const wchar_t* src,
    size_t src_length,  /* = 0 */
    size_t* out_length  /* = NULL */
    )
{
	if(!src)
		{ return NULL; }

	if(src_length == 0) { src_length = wcslen(src); }
	int length = WideCharToMultiByte(CP_UTF8, 0, src, src_length,
			0, 0, NULL, NULL);
	char *output_buffer = (char*)malloc((length+1) * sizeof(char));
	if(output_buffer) {
		WideCharToMultiByte(CP_UTF8, 0, src, src_length,
				output_buffer, length, NULL, NULL);
		output_buffer[length] = '\0';
	}
    if(out_length) { *out_length = length; }
	return output_buffer;
}