[v1s2222]

Замени везде String -> AnsiString, Char - AnsiChar, PChar - PAnsiChar.

Код:

function UrlEncode(Str: ansistring): ansistring;

  function CharToHex(Ch: ansiChar): Integer;
  asm
    and eax, 0FFh
    mov ah, al
    shr al, 4
    and ah, 00fh
    cmp al, 00ah
    jl @@10
    sub al, 00ah
    add al, 041h
    jmp @@20
@@10:
    add al, 030h
@@20:
    cmp ah, 00ah
    jl @@30
    sub ah, 00ah
    add ah, 041h
    jmp @@40
@@30:
    add ah, 030h
@@40:
    shl eax, 8
    mov al, '%'
  end;

var
  i, Len: Integer;
  Ch: ansiChar;
  N: Integer;
  P: PansiChar;
begin
  Result := '';
  Len := Length(Str);
  P := PansiChar(@N);
  for i := 1 to Len do
  begin
    Ch := Str[i];
    if Ch in ['0'..'9', 'A'..'Z', 'a'..'z', '_'] then
      Result := Result + Ch
    else
    begin
      if Ch = ' ' then
        Result := Result + '+'
      else
      begin
        N := CharToHex(Ch);
        Result := Result + P;
      end;
    end;
  end;
end;

 function UrlDecode(Str: Ansistring): Ansistring;

  function HexToChar(W: word): AnsiChar;
  asm
   cmp ah, 030h
   jl @@error
   cmp ah, 039h
   jg @@10
   sub ah, 30h
   jmp @@30
@@10:
   cmp ah, 041h
   jl @@error
   cmp ah, 046h
   jg @@20
   sub ah, 041h
   add ah, 00Ah
   jmp @@30
@@20:
   cmp ah, 061h
   jl @@error
   cmp al, 066h
   jg @@error
   sub ah, 061h
   add ah, 00Ah
@@30:
   cmp al, 030h
   jl @@error
   cmp al, 039h
   jg @@40
   sub al, 030h
   jmp @@60
@@40:
   cmp al, 041h
   jl @@error
   cmp al, 046h
   jg @@50
   sub al, 041h
   add al, 00Ah
   jmp @@60
@@50:
   cmp al, 061h
   jl @@error
   cmp al, 066h
   jg @@error
   sub al, 061h
   add al, 00Ah
@@60:
   shl al, 4
   or al, ah
   ret
@@error:
   xor al, al
  end;

  function GetCh(P: PAnsiChar; var Ch: AnsiChar): AnsiChar;
  begin
    Ch := P^;
    Result := Ch;
  end;

var
  P: PAnsiChar;
  Ch: AnsiChar;
begin
  Result := '';
  P := @Str[1];
  while GetCh(P, Ch) <> #0 do
  begin
    case Ch of
      '+': Result := Result + ' ';
      '%':
        begin
          Inc(P);
          Result := Result + HexToChar(PWord(P)^);
          Inc(P);
        end;
    else
      Result := Result + Ch;
    end;
    Inc(P);
  end;
end;

  Edit1.Text:= UrlEncode(Edit1.Text);
  Edit2.Text:=URLDecode(edit1.Text);