UTF16toUTF8

UTF16toUTF8.cpp

static int UTF16len(unsigned short   *utf16)  
{  
    unsigned short * start = utf16;  
    while(*utf16++) ;  
    return (int)(utf16 - start - 1);  
}  

size_t __UTF16toUTF8(const unsigned short utf16char, char* utf8str) {
    if (utf16char < 0x80) {
		utf8str[0] = (utf16char >> 0 & 0x7F) | 0x00;
		return 1;
	} else if (utf16char < 0x0800) {
		utf8str[0] = (utf16char >> 6 & 0x1F) | 0xC0;
		utf8str[1] = (utf16char >> 0 & 0x3F) | 0x80;
		return 2;
	} else if (utf16char < 0x010000) {
		utf8str[0] = (utf16char >> 12 & 0x0F) | 0xE0;
		utf8str[1] = (utf16char >> 6 & 0x3F) | 0x80;
		utf8str[2] = (utf16char >> 0 & 0x3F) | 0x80;
		return 3;
	} else if (utf16char < 0x110000) {
		utf8str[0] = (utf16char >> 18 & 0x07) | 0xF0;
		utf8str[1] = (utf16char >> 12 & 0x3F) | 0x80;
		utf8str[2] = (utf16char >> 6 & 0x3F) | 0x80;
		utf8str[3] = (utf16char >> 0 & 0x3F) | 0x80;
		return 4;
	}
	return 0;
}

static void UTF16toUTF8(const short *src, char *dst){
    int len = UTF16len(src);
    unsigned short *end = src + len;  
    while (src < end){
		dst += __UTF16toUTF8(*src,dst);
		src++;
	}
	*dst = 0;
}