// Delphi Encoder Class for Code128 and UCC/EAN128
// Copyright 2005 by MW6 Technologies Inc. All rights reserved.
//
// This code may not be modified or distributed unless you purchase
// the license from MW6.

unit Encoder;

interface

uses
   SysUtils;

type
   TEncoder = class
   private
        I: Integer;
        StrLen: Integer;
        Sum: Integer;
        CurrSet: Integer;
        CurrChar: Integer;
        NextChar: Integer;
        EncodedMessage: AnsiString;
        Weight: Integer;
        Buf: array[0..255] of Char;
        
        procedure GeneralEncode();

   public
        constructor Create; overload;

        function Code128Auto(var Src: string): string;
        function Code128A(var Src: string): string;
        function Code128B(var Src: string): string;
        function Code128C(var Src: string): string;
        function UCCEAN128(var Src: string): string;
   end;

implementation

constructor TEncoder.Create;
begin
  inherited;
end;

procedure TEncoder.GeneralEncode();
var
  tmp: Integer;
  CurrDone: boolean;
begin
  I := 1;
  while (I <= StrLen) do
  begin
       CurrChar := Ord(Buf[I - 1]);
       CurrDone := false;
       if ((I + 1) <= StrLen) then
       begin
            NextChar := Ord(Buf[I]);
            If (CurrChar >= Ord('0')) And (CurrChar <= Ord('9')) And
               (NextChar >= Ord('0')) And (NextChar <= Ord('9')) Then
            begin
                tmp := (CurrChar - Ord('0')) * 10 + (NextChar - Ord('0'));

                // 2 digits
                if (CurrSet <> 3) Then
                begin
                    // the previous set is not Set C
                    EncodedMessage := ENcodedMessage + Chr(99 + 98);
                    Sum := Sum + Weight * 99;
                    Weight := Weight + 1;
                    CurrSet := 3;
                end;

                If (tmp = 0) then
                    EncodedMessage := EncodedMessage + Chr(192)
                else if (tmp > 0) And (tmp < 95) Then
                    EncodedMessage := EncodedMessage + Chr(tmp + 32)
                else
                    EncodedMessage :=  EncodedMessage + Chr(tmp + 98);

                Sum := Sum + Weight * tmp;
                I := I + 2;

                CurrDone := True;
            end;
        end;

        If (Not CurrDone) Then
        begin
            if (CurrChar >= 0) And (CurrChar <= 31) Then
            begin
                // choose Set A
                if (CurrSet <> 1) Then
                begin
                    // the previous set is not Set A
                    EncodedMessage := EncodedMessage + Chr(101 + 98);
                    Sum := Sum + Weight * 101;
                    Weight := Weight + 1;
                    CurrSet := 1;
                end;

                if (CurrChar = 31) Then
                begin
                    EncodedMessage := EncodedMessage + Chr(193);
                    Sum := Sum + Weight * 95;
                end
                else
                begin
                    EncodedMessage := EncodedMessage + Chr(CurrChar + 96);
                    Sum := Sum + Weight * (CurrChar + 64);
                end;
            end
            else
            begin
                // choose Set B
                if (CurrSet <> 2) Then
                begin
                   // the previous set is not Set B
                   EncodedMessage := EncodedMessage + Chr(100 + 98);
                   Sum := Sum + Weight * 100;
                   Weight := Weight + 1;
                   CurrSet := 2;
                end;

                if (CurrChar = 32) Then
                   EncodedMessage := EncodedMessage + Chr(192)
                else if (CurrChar = 127) Then
                begin
                   EncodedMessage := EncodedMessage + Chr(193);
                   Sum := Sum + Weight * 95;
                end
                else if (CurrChar < 127) And (CurrChar > 32) Then
                begin
                   EncodedMessage := EncodedMessage + Chr(CurrChar);
                   Sum := Sum + Weight * (CurrChar - 32);
                end;
            end;

            I := I + 1;
        end;

        Weight := Weight + 1;
  end;

  // add CheckDigit
  Sum := Sum Mod 103;
  If (Sum = 0) Then
     EncodedMessage := EncodedMessage + Chr(192)
  else if (Sum <= 94) Then
     EncodedMessage := EncodedMessage + Chr(Sum + 32)
  else
     EncodedMessage := EncodedMessage + Chr(Sum + 98);

  // add stop character (204)
  EncodedMessage := EncodedMessage + Chr(204);
end;

function TEncoder.Code128Auto(var Src: string): string;
begin
    StrLen := Length(Src);
    Sum := 104;

    // 2 indicates Set B
    CurrSet := 2;

    // start character with value 202 for Set B
    EncodedMessage := ''  + Chr(202);

    StrPCopy(Buf, Src);
    CurrChar := Ord(Buf[0]);
    If (CurrChar <= 31) ANd (CurrChar >= 0) then
    begin
        // switch to Set A
        // 1 indicates Set A
        CurrSet := 1;

        // start character with value 201 for Set A
        EncodedMessage := '' + Chr(201);
        Sum := 103;
    end;

    Weight := 1;
    GeneralEncode();

    Result := EncodedMessage;
end;

function TEncoder.UCCEAN128(var Src: string): string;
begin
    StrLen := Length(Src);
    Sum := 105;

    // 3 indicates Set C
    CurrSet := 3;

    // start character (203) + FNC1 (200)
    EncodedMessage := '' + Chr(203) + Chr(200);
    Sum := Sum + 102;
    Weight := 2;

    StrPCopy(Buf, Src);
    GeneralEncode();

    Result := EncodedMessage;
end;

function TEncoder.Code128A(var Src: string): string;
var
    m: Integer;
begin
    StrLen := Length(Src);
    Sum := 103;

    // start character (201) for Set A
    EncodedMessage := '' + Chr(201);

    Weight := 1;
    StrPCopy(Buf, Src);
    For m := 1 To StrLen do
    begin
        CurrChar := Ord(Buf[m - 1]);
        If (CurrChar = 32) Then
            EncodedMessage := EncodedMessage + Chr(192)
        else If (CurrChar = 31) Then
        begin
            EncodedMessage := EncodedMessage + Chr(193);
            Sum := Sum + Weight * 95;
        end
        else if (CurrChar <= 95) And (CurrChar > 32) Then
        begin
            EncodedMessage := EncodedMessage + Chr(CurrChar);
            Sum := Sum + Weight * (CurrChar - 32);
        end
        else if (CurrChar >= 0) And (CurrChar <= 31) Then
        begin
            EncodedMessage := EncodedMessage + Chr(CurrChar + 96);
            Sum := Sum + Weight * (CurrChar + 64);
        end
        else
        begin
            Result := Code128Auto(Src);
            Exit;
        end;
        Weight := Weight + 1;
    end;

    // add CheckDigit
    Sum := Sum Mod 103;
    If (Sum = 0) Then
       EncodedMessage := EncodedMessage + Chr(192)
    else if (Sum <= 94) Then
       EncodedMessage := EncodedMessage + Chr(Sum + 32)
    else
       EncodedMessage := EncodedMessage + Chr(Sum + 98);

    // add stop character (204)
    EncodedMessage := EncodedMessage + Chr(204);

    Result := EncodedMessage;
end;

function TEncoder.Code128B(var Src: string): string;
var
    m: Integer;
begin
    StrLen := Length(Src);
    Sum := 104;

    // start character (202) for Set B
    EncodedMessage := '' + Chr(202);

    Weight := 1;
    StrPCopy(Buf, Src);
    For m := 1 To StrLen do
    begin
        CurrChar := Ord(Buf[m - 1]);
        if (CurrChar = 32) Then
            EncodedMessage := EncodedMessage + Chr(192)
        else if (CurrChar = 127) Then
        begin
            EncodedMessage := EncodedMessage + Chr(193);
            Sum := Sum + Weight * 95;
        end
        else if (CurrChar < 127) And (CurrChar > 32) Then
        begin
            EncodedMessage := EncodedMessage + Chr(CurrChar);
            Sum := Sum + Weight * (CurrChar - 32);
        end
        else
        begin
            Result := Code128Auto(Src);
            Exit;
        end;

        Weight := Weight + 1;
    end;

     // add CheckDigit
    Sum := Sum Mod 103;
    If (Sum = 0) Then
       EncodedMessage := EncodedMessage + Chr(192)
    else if (Sum <= 94) Then
       EncodedMessage := EncodedMessage + Chr(Sum + 32)
    else
       EncodedMessage := EncodedMessage + Chr(Sum + 98);

    // add stop character (204)
    EncodedMessage := EncodedMessage + Chr(204);

    Result := EncodedMessage;
end;

function TEncoder.Code128C(var Src: string): string;
var
    tmp: Integer;
begin
    StrLen := Length(Src);
    Sum := 105;

    // start character (203) for Set C
    EncodedMessage := '' + Chr(203);

    Weight := 1;
    I := 1;
    StrPCopy(Buf, Src);
    While (I <= StrLen) do
    begin
        CurrChar := Ord(Buf[I - 1]);
        if ((I + 1) <= StrLen) then
        begin
            NextChar := Ord(Buf[I]);

            If (CurrChar >= Ord('0')) And (CurrChar <= Ord('9')) And
               (NextChar >= Ord('0')) And (NextChar <= Ord('9')) then
            begin
                // 2 digits
                tmp := (CurrChar - Ord('0')) * 10 + (NextChar - Ord('0'));

                If (tmp = 0) Then
                    EncodedMessage := EncodedMessage + Chr(192)
                else if (tmp > 0) And (tmp < 95) Then
                    EncodedMessage := EncodedMessage + Chr(tmp + 32)
                else
                    EncodedMessage := EncodedMessage + Chr(tmp + 98);

                Sum := Sum + Weight * tmp;
                I := I + 2;
            end
            else
            begin
                Result := Code128Auto(Src);
                Exit;
            end;
        end
        else
        begin
            EncodedMessage := EncodedMessage +  Chr(198);
            Sum := Sum + Weight * 100;
            Weight := Weight + 1;

            if (CurrChar = 32) then
                EncodedMessage := EncodedMessage + Chr(192)
            else if (CurrChar = 127) then
            begin
                EncodedMessage := EncodedMessage + Chr(193);
                Sum := Sum + Weight * 95;
            end
            else if (CurrChar < 127) And (CurrChar > 32) then
            begin
                EncodedMessage := EncodedMessage +  Chr(CurrChar);
                Sum := Sum + Weight * (CurrChar - 32);
            end
            else
            begin
                Result := Code128Auto(Src);
                Exit;
            end;

            I := I + 1;
        end;

        Weight := Weight + 1;
    end;

     // add CheckDigit
    Sum := Sum Mod 103;
    If (Sum = 0) Then
       EncodedMessage := EncodedMessage + Chr(192)
    else if (Sum <= 94) Then
       EncodedMessage := EncodedMessage + Chr(Sum + 32)
    else
       EncodedMessage := EncodedMessage + Chr(Sum + 98);

    // add stop character (204)
    EncodedMessage := EncodedMessage + Chr(204);

    Result := EncodedMessage;
end;

end.