/* encoding */	
        //// ...
        if (check & (ENCODE_PERLQQ|ENCODE_HTMLCREF|ENCODE_XMLCREF)){
            SV* subchar = 
            (fallback_cb != &PL_sv_undef)
		? do_fallback_cb(aTHX_ ch, fallback_cb)
		: newSVpvf(check & ENCODE_PERLQQ ? "\\x{%04"UVxf"}" :
                 check & ENCODE_HTMLCREF ? "&#%" UVuf ";" :
                 "&#x%" UVxf ";", (UV)ch);
	    SvUTF8_off(subchar); /* make sure no decoded string gets in */
            sdone += slen + clen;
            ddone += dlen + SvCUR(subchar);
            sv_catsv(dst, subchar);
            SvREFCNT_dec(subchar);
        } else {
            /* fallback char */
            sdone += slen + clen;
            ddone += dlen + enc->replen;
            sv_catpvn(dst, (char*)enc->rep, enc->replen);
        }

##</code><code>##

        /* decoding */
        //// ...
        if (check &
            (ENCODE_PERLQQ|ENCODE_HTMLCREF|ENCODE_XMLCREF)){
            SV* subchar = 
            (fallback_cb != &PL_sv_undef)
		? do_fallback_cb(aTHX_ (UV)s[slen], fallback_cb) 
		: newSVpvf("\\x%02" UVXf, (UV)s[slen]);
            sdone += slen + 1;
            ddone += dlen + SvCUR(subchar);
            sv_catsv(dst, subchar);
            SvREFCNT_dec(subchar);
        } else {
            sdone += slen + 1;
            ddone += dlen + strlen(FBCHAR_UTF8);
            sv_catpv(dst, FBCHAR_UTF8);
        }

##</code><code>##

    malformed:
        //// ...
        if (check & (ENCODE_PERLQQ|ENCODE_HTMLCREF|ENCODE_XMLCREF)){
	    SV* subchar =
		(fallback_cb != &PL_sv_undef)
		? do_fallback_cb(aTHX_ uv, fallback_cb)
		: newSVpvf(check & ENCODE_PERLQQ 
			   ? (ulen == 1 ? "\\x%02" UVXf : "\\x{%04" UVXf "}")
			   :  check & ENCODE_HTMLCREF ? "&#%" UVuf ";" 
			   : "&#x%" UVxf ";", uv);
	    if (encode){
		SvUTF8_off(subchar); /* make sure no decoded string gets in */
	    }
            sv_catsv(dst, subchar);
            SvREFCNT_dec(subchar);
        } else {
            sv_catpv(dst, FBCHAR_UTF8);
        }