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Need Help Converting C Code to Delphi

Posted on 2004-10-18
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Last Modified: 2010-04-05
Below is some C code I'm trying to get working in Delphi but it uses some C stuff I'm not completely clear about in the Delphi world.

Someone please help me convert this to the Delphi equivalent. I'm not concerned with the COM PORT stuff shown; a text box showing the final values is fine for my needs (I'm just looking for a working example):

//CALC CHECKSUM FOR RCVD ASCII STRING, RETURN CHECKSUM VAL 0 = GOOD
//EXAMPLE:
// as00 = 06as0066 (VALID)

// 06 = PKT LEN
// as = PKT CMD
// 00 = PKT VAL
// 66 = CHECKSUM

INT8U itAscRecBuf[82];      
INT8U AscHexToBin(INT8U, INT8U *);
INT8U AsciiToHex( INT8U);      

INT8U CalcCheckSum(void)
{
      INT8U i,length, cc;

      length = AscHexToBin(2, &itAscRecBuf[0]);      //PKT LEN=POS1 & POS2
      cc = AscHexToBin(2, &itAscRecBuf[length]);
      for (i=0;i<length ;i++ )
      {
            cc += itAscRecBuf[i];
      }
      return(cc);      //GOOD CHECKSUM = 0
}

INT8U AscHexToBin(INT8U Width, INT8U * DataPtr)
{
      INT8U aVal;

      aVal = AsciiToHex(*DataPtr);
      DataPtr++;
      if (Width == 2)
      {
            aVal = aVal << 4;
            aVal += AsciiToHex(*DataPtr);
      }
      return(aVal);
}

INT8U AsciiToHex( INT8U Value )
{
      switch ( Value )
      {
            case 'A':
                  return( 10 );
            case 'B':
                  return( 11 );
            case 'C':
                  return( 12 );
            case 'D':
                  return( 13 );
            case 'E':
                  return( 14 );
            case 'F':
                  return( 15 );
            default:
                  return( Value - 0x30 );
      }
}

// SEND CHECKSUM + CR/LF
// (QUICK USAGE EXAMPLE USING COM PORT)

INT8U NibToAsc(INT8U);

void SendChecksum(INT8U CC)
{
      CC = (CC ^ 0xFF) + 1;
      Comm2_Put_Ch(NibToAsc(CC >> 4));
      Comm2_Put_Ch(NibToAsc(CC & 0x0F));
      Comm2_Put_Ch(0x0D);
      Comm2_Put_Ch(0x0A);
}

INT8U NibToAsc(INT8U Nib)
{
      if (Nib < 0x0A)
            return( (INT8U)(Nib + 0x30));
      else if (Nib <= 0x0F)
            return(Nib + 0x37);
      return(0x20);
}      
0
Comment
Question by:MediaStorm
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4 Comments
 
LVL 6

Accepted Solution

by:
vadim_ti earned 500 total points
ID: 12341668
unit Unit1;

interface

implementation


//CALC CHECKSUM FOR RCVD ASCII STRING, RETURN CHECKSUM VAL 0 = GOOD
//EXAMPLE:
// as00 = 06as0066 (VALID)

// 06 = PKT LEN
// as = PKT CMD
// 00 = PKT VAL
// 66 = CHECKSUM




// SEND CHECKSUM + CR/LF
// (QUICK USAGE EXAMPLE USING COM PORT)
var
itAscRecBuf: array [0..100] of Byte;

procedure Comm2_Put_Ch(ch:Byte);
begin
end;

function AsciiToHex(Value: Byte ):Byte;
begin
  if chr(value) in ['A'..'F'] then
    result := value - ord('A') + 10
  else
    result := value - $30;
end;

function AscHexToBin(Width:Byte; Ptr: Pointer):Byte;
var
     aVal, ch: Byte;
     DataPtr: PChar;
begin

     DataPtr := ptr;
     ch := ord(DataPtr^);
     aVal := AsciiToHex(ch);
     Inc(DataPtr);
     if (Width = 2) then begin
          aVal := aVal shl 4;
          ch := ord(DataPtr^);
          Inc(aVal , AsciiToHex(ch));
     end;
     result := aVal;
end;


function CalcCheckSum: Byte;
var
     i,length, cc: Byte;
begin

     length := AscHexToBin(2, @itAscRecBuf[0]);     //PKT LEN=POS1 & POS2
     cc := AscHexToBin(2, @itAscRecBuf[length]);
     for i:=0 to length-1 do
          INC(cc, itAscRecBuf[i]);
     result := cc;     //GOOD CHECKSUM = 0
end;

function NibToAsc(Nib:Byte):Byte ;
begin
     if Nib < $A then
       result := Nib + $30
     else if Nib <= $F  then
       result := Nib + $37
     else
       result := $20
end;

procedure SendChecksum(CC:Byte);
begin
     CC := (CC xor $FF) + 1;
     Comm2_Put_Ch(NibToAsc(CC shr 4));
     Comm2_Put_Ch(NibToAsc(CC and $F));
     Comm2_Put_Ch($D);
     Comm2_Put_Ch($A);
end;

end.
0
 
LVL 1

Author Comment

by:MediaStorm
ID: 12342183
That's really, really close. What I need to do is be able to send a string to the SendChecksum procedure and return the formatted string including the length, data and checksum.

IE - I would pass it: SendChecksum('as00') and the result would be '06as0066'.

Length = data + lengthVal

The checksum would be calc'd from '06as00' in this case and the result would be '66' conccat'd result = '06as0066'

Does that make sense? I'm happy to bump up the points for the great help and fast response time you've provided as well.
0
 
LVL 6

Expert Comment

by:vadim_ti
ID: 12342614
i do not know about  sense
i only converted you your functions

0
 
LVL 1

Author Comment

by:MediaStorm
ID: 12343850
Not a problem.. I'll figure it out. Thanks for the help.
0

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