unit DzURL;

{ By Alexander Dzyubenko
     alexander@dzsoft.com
     http://www.dzsoft.com }

interface

uses SysUtils;

function UrlEncode(const DecodedStr: String; Pluses: Boolean): String;
// Encodes standard string into URL data format.
// Example: http://www.dzsoft.com -> http%3A%2F%2Fwww.dzsoft.com%2F
// Pluses parameter specifies whether spaces will be 
// encoded as '+' or as '%20'

function UrlDecode(const EncodedStr: String): String;
// Decodes URL data into a readable string.
// Example: http%3A%2F%2Fwww.dzsoft.com%2F -> http://www.dzsoft.com

function HexToInt(HexStr: String): Int64;
// Taken from http://www.delphi3000.com/article.asp?id=1412

implementation

function UrlEncode(const DecodedStr: String; Pluses: Boolean): String;
var
  I: Integer;
begin
  Result := '';
  if Length(DecodedStr) > 0 then
    for I := 1 to Length(DecodedStr) do
    begin
      if not (DecodedStr[I] in ['0'..'9', 'a'..'z',
                                       'A'..'Z', ' ']) then
        Result := Result + '%' + IntToHex(Ord(DecodedStr[I]), 2)
      else if not (DecodedStr[I] = ' ') then
        Result := Result + DecodedStr[I]
      else
        begin
          if not Pluses then
            Result := Result + '%20'
          else
            Result := Result + '+';
        end;
    end;
end;

function UrlDecode(const EncodedStr: String): String;
var
  I: Integer;
begin
  Result := '';
  if Length(EncodedStr) > 0 then
  begin
    I := 1;
    while I <= Length(EncodedStr) do
    begin
      if EncodedStr[I] = '%' then
        begin
          Result := Result + Chr(HexToInt(EncodedStr[I+1]
                                       + EncodedStr[I+2]));
          I := Succ(Succ(I));
        end
      else if EncodedStr[I] = '+' then
        Result := Result + ' '
      else
        Result := Result + EncodedStr[I];

      I := Succ(I);
    end;
  end;
end;

function HexToInt(HexStr: String): Int64;
var RetVar : Int64;
    i : byte;
begin
  HexStr := UpperCase(HexStr);
  if HexStr[length(HexStr)] = 'H' then
     Delete(HexStr,length(HexStr),1);
  RetVar := 0;

  for i := 1 to length(HexStr) do begin
      RetVar := RetVar shl 4;
      if HexStr[i] in ['0'..'9'] then
         RetVar := RetVar + (byte(HexStr[i]) - 48)
      else
         if HexStr[i] in ['A'..'F'] then
            RetVar := RetVar + (byte(HexStr[i]) - 55)
         else begin
            Retvar := 0;
            break;
         end;
  end;

  Result := RetVar;
end;

end.