// Punycode Konvertierung
//
// Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA)
// http://www.rfc-editor.org/rfc/rfc3492.txt
//
// Delphi-Unit von Daniel Mitte (2005)
// Original-Code von http://www.activevb.de
//
// Beispiel:
// pc := TPunyClass.Create;
// e := pc.Encode('müller'); // Verschlüsselt 'müller' zu 'mller-kva'
// d := pc.Decode(e); // Entschlüsselt 'mller-kva' zu 'müller'
// pc.Free;
unit puny;
interface
const
BASE: Longint = 36;
TMIN: Longint = 1;
TMAX: Longint = 26;
SKEW: Longint = 38;
DAMP: Longint = 700;
INITIAL_BIAS: Longint = 72;
INITIAL_N: Longint = 128;
Delimiter: WideString = '
-';
MAX_INT: Longint = $7FFFFFFF;
//= MAXINT
type TPunyClass =
class
private
function GetMinCodePoint(
const n: Longint;
const data: WideString): Longint;
function IsBasic(c: WideString;
const n: Longint): Boolean;
function Adapt(
const delta, numpoints: Longint;
const firsttime: Boolean): Longint;
function Digit2Codepoint(
const d: Longint): Longint;
function Codepoint2Digit(
const c: Longint): Longint;
function UInt(i: Longint): Longint;
function Asc(s: WideString): Longint;
function AscW(s: WideString): Longint;
function PosRev(sub, text: WideString): Longint;
public
function Encode(input: WideString): WideString;
function Decode(input: WideString): WideString;
end;
implementation
function TPunyClass.Encode(input: WideString): WideString;
var
n, delta, bias, b, l, h, q, m, k, t: Longint;
text, output, c: WideString;
first: Boolean;
begin
text := input;
output := '
';
try
n := INITIAL_N;
bias := INITIAL_BIAS;
b := 0;
for l := 1
to Length(text)
do
begin
//c := Copy(text, l, 1);
c := text[l];
if IsBasic(c, INITIAL_N)
then
begin
output := output + c;
b := b + 1;
end;
end;
if Length(output) < Length(text)
then
if Length(output) > 0
then output := output + Delimiter;
h := b;
delta := 0;
while h < Length(text)
do
begin
m := GetMinCodePoint(n, text);
delta := delta + UInt(m - n) * (h + 1);
n := m;
for l := 1
to Length(text)
do
begin
c := text[l];
if IsBasic(c, n)
then delta := delta + 1
else if UInt(AscW(c)) = n
then
begin
q := delta;
k := BASE;
while k <= MAX_INT
do
begin
if k <= (bias + TMIN)
then t := TMIN
else if k >= (bias + TMAX)
then t := TMAX
else t := k - bias;
if q < t
then break;
output := output + Chr(Digit2Codepoint(t + ((q - t)
Mod (BASE - t))));
q := (q - t)
div (BASE - t);
k := k + BASE;
end;
output := output + Chr(Digit2Codepoint(q));
first := h = b;
bias := Adapt(delta, h + 1, first);
delta := 0;
h := h + 1;
end;
end;
delta := delta + 1;
n := n + 1;
end;
except
output := input;
end;
Result := output;
end;
function TPunyClass.Decode(input: WideString): WideString;
var
n, i, bias, l, ps, oldi, w, k, t: Longint;
digit: Byte;
text, output, c: WideString;
first: Boolean;
begin
text := input;
output := '
';
try
n := INITIAL_N;
bias := INITIAL_BIAS;
i := 0;
ps := PosRev(Delimiter, text);
if ps > 0
then
begin
for l := 1
to (ps - 1)
do
begin
c := text[l];
if IsBasic(c, INITIAL_N)
then output := output + c
else
begin
Result := '
';
Exit;
end;
end;
end;
ps := ps + 1;
while ps <= Length(text)
do
begin
oldi := i;
w := 1;
k := BASE;
while ((k <= MAX_INT)
and (ps <= Length(text)))
do
begin
c := text[ps];
ps := ps + 1;
digit := Codepoint2Digit(Asc(c));
if ((digit >= BASE)
or (digit > ((MAX_INT - i) / w)))
then
begin
Result := '
';
Exit;
end;
i := i + digit * w;
if k <= bias
then t := TMIN
else if k >= (bias + TMAX)
then t := TMAX
else t := k - bias;
if digit < t
then break;
if w > (maxint / (base - t))
then
begin
Result := '
';
Exit;
end;
w := w * (BASE - t);
k := k + BASE;
end;
first := oldi = 0;
bias := Adapt(i - oldi, Length(output) + 1, first);
if (i / (Length(output) + 1)) > (MAX_INT - n)
then
begin
Result := '
';
Exit;
end;
n := n + i
div (Length(output) + 1);
i := i
mod (Length(output) + 1);
if IsBasic(WideChar(n), INITIAL_N)
then
begin
Result := '
';
Exit;
end;
output := Copy(output, 1, i) + WideChar(n) + Copy(output, i + 1, Length(output) - (i + 1) + 1);
i := i + 1;
end;
except
output := input;
end;
Result := output;
end;
function TPunyClass.GetMinCodePoint(
const n: Longint;
const data: WideString): Longint;
var
t, a, res: Longint;
begin
res := MAX_INT;
for t := 1
to Length(data)
do
begin
a := UInt(AscW(Copy(data, t, 1)));
if ((a >= n)
and (a < res))
then res := a;
end;
Result := res;
end;
function TPunyClass.IsBasic(c: WideString;
const n: Longint): Boolean;
begin
Result := UInt(AscW(c)) < n;
end;
function TPunyClass.Adapt(
const delta, numpoints: Longint;
const firsttime: Boolean): Longint;
var
k, dt: Longint;
begin
dt := delta;
if firsttime
then dt := dt
div DAMP
else dt := dt
div 2;
dt := dt + (dt
div numpoints);
k := 0;
while dt > (((BASE - TMIN) * TMAX)
div 2)
do
begin
dt := dt
div (BASE - TMIN);
k := k + BASE;
end;
Result := k + (((BASE - TMIN + 1) * dt)
div (dt + SKEW));
end;
function TPunyClass.Digit2Codepoint(
const d: Longint): Longint;
begin
Result := 0;
if d < 26
then Result := d + 97
else if d < 36
then Result := d - 26 + 48;
end;
function TPunyClass.Codepoint2Digit(
const c: Longint): Longint;
begin
Result := BASE;
if (c - 48) < 10
then Result := c - 22
else if (c - 65) < 26
then Result := c - 65
else if (c - 97) < 26
then Result := c - 97;
end;
function TPunyClass.UInt(i: Longint): Longint;
begin
Result := i;
if i < 0
then Result := 65536 + i;
end;
function TPunyClass.Asc(s: WideString): Longint;
var
c: WideChar;
begin
Result := 0;
if Length(s) > 0
then
begin
c := s[1];
Result := Word(c);
end;
end;
function TPunyClass.AscW(s: WideString): Longint;
var
c: WideChar;
begin
Result := 0;
if s <> '
'
then
begin
c := s[1];
Result := Longint(c);
end;
end;
function TPunyClass.PosRev(sub, text: WideString): Longint;
var
p: Longint;
s: WideString;
begin
Result := 0;
s := '
';
for p := 1
to Length(text)
do s := s + Copy(text, Length(text) - p + 1, 1);
p := Pos(sub, s);
if p > 0
then Result := Length(s) - p + 1;
end;
end.