09-03-2010, 11:11 PM
Protocol Description Unit -PDU
PDU Encode/Decode ترميز سريع وفك الترميز الصيغ PDUكود :
procedure Bin2Hex(Buffer, Text: PChar; BufSize: Integer); assembler;
const
Convert: array[0..15] of Char = '0123456789ABCDEF';
p: array[1..7] of Byte = ($1, $3, $7, $F, $1F, $3F, $7F);
var
i, Count: Integer;
c, Tmp, r: Byte;
begin
r:= Byte(Buffer[0]);
Count:= 1;
for i := 0 to BufSize - 1 do
if Count < 8 then
begin
c:= r;
if i < (BufSize - 1) then
begin
Tmp:= Byte(Buffer[I + 1]);
r:= Tmp shr Count;
c:= c or ((Tmp and p[Count]) shl (8 - Count));
Inc(Count);
end;
Text[0] := Convert[c shr 4];
Text[1] := Convert[c and $F];
Inc(Text, 2);
end
else
begin
Count:= 1;
if i < BufSize then
r:= Byte(Buffer[i + 1]);
end;
end;
function Hex2Bin(Text, Buffer: PChar; BufSize: Integer): Integer; assembler;
const
Convert: array['0'..'f'] of SmallInt =
( 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,10,11,12,13,14,15);
p: array[1..7] of Byte = ($7F, $3F, $1F, $F, $7, $3, $1);
var
i, Count: Integer;
Tmp, c, r: Byte;
begin
I := BufSize;
Count:= 1;
while i > 0 do
begin
if not (Text[0] in ['0'..'f']) or not (Text[1] in ['0'..'f']) then Break;
c:= (Convert[Text[0]] shl 4) + Convert[Text[1]];
tmp:= c shr (8 - Count);
c:= c and p[Count];
if Count > 1 then
c:= (c shl (Count - 1)) or r;
r:= Tmp;
Buffer[0] := Char(c);
if Count = 7 then
begin
Inc(Buffer);
Buffer[0] := Char(r);
Count:= 1;
end
else
Inc(Count);
Inc(Buffer);
Inc(Text, 2);
Dec(i);
end;
Result := BufSize - i;
end;
function EncodePDU7bits(const Source: String): String;
var Leng: Integer;
begin
Leng:= Length(Source);
Leng:= (Leng * 2)- ((Leng div 8) * 2);
SetLength(Result, Leng);
Bin2Hex(PChar(Source), PChar(Result), Length(Source));
end;
function DecodePDU7bits(const CodedStr: String): String;
var Leng: Integer;
begin
Leng:= Length(CodedStr) div 2;
SetLength(Result, Leng+ (Leng div 7));
Hex2Bin(PChar(CodedStr), PChar(Result), Leng);
end;كود :
procedure TForm1.Button1Click(Sender: TObject);
begin
Memo3.Text:= EncodePDU7bits(Memo1.Text);
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Memo2.Text:= DecodePDU7bits(Memo3.Text);
end;