ASCII to HEX (math)

These work on byte array to strings, also look at the Ord and Chr functions in Delphi.

BytesToHexStr does this [0,1,1,0] of byte would be converted to string := '30313130'; HexStrToBytes goes the other way.

unit Hexstr;

interface

uses String16, SysUtils;

Type

PByte = ^BYTE;

procedure BytesToHexStr(var hHexStr: String; pbyteArray: PByte; InputLength: WORD);

procedure HexStrToBytes(hHexStr: String; pbyteArray: Pointer);

procedure HexBytesToChar(var Response: String; hexbytes: PChar; InputLength: WORD);

implementation

procedure BytesToHexStr(var hHexStr: String; pbyteArray: PByte; InputLength: WORD);

Const

HexChars : Array[0..15] of Char = '0123456789ABCDEF';

var

i, j: WORD;

begin

SetLength(hHexStr, (InputLength * 2));

FillChar(hHexStr, sizeof(hHexStr), #0);

j := 1;

for i := 1 to InputLength do begin

hHexStr[j] := Char(HexChars[pbyteArray^ shr 4]); inc(j);

hHexStr[j] := Char(HexChars[pbyteArray^ and 15]); inc(j);

inc(pbyteArray);

end;

procedure HexBytesToChar(var Response: String; hexbytes: PChar; InputLength: WORD);

var

i: WORD;

c: byte;

begin

SetLength(Response, InputLength);

FillChar(Response, SizeOf(Response), #0);

for i := 0 to (InputLength - 1) do begin

c := BYTE(hexbytes[i]) And BYTE($f);

if c > 9 then

Inc(c, $37)

else

Inc(c, $30);

Response[i + 1] := char(c);

end;{for}

end;

procedure HexStrToBytes(hHexStr: String; pbyteArray: Pointer);

{pbyteArray must point to enough memory to hold the output}

var

i, j: WORD;

tempPtr: PChar;

twoDigits : String[2];

begin

tempPtr := pbyteArray;

j := 1;

for i := 1 to (Length(hHexStr) DIV 2) do begin

twoDigits := Copy(hHexStr, j, 2); Inc(j, 2);

PByte(tempPtr)^ := StrToInt('$' + twoDigits); Inc(tempPtr);

end;{for}

end;

end.

UNIT String16.

interface

{$IFNDEF Win32}

procedure SetLength(var S: string; Len: Integer);

procedure SetString(var Dst: string; Src: PChar; Len: Integer);

{$ENDIF}

implementation

{$IFNDEF Win32}

procedure SetLength(var S: string; Len: Integer);

begin

if Len > 255 then

S[0] := Chr(255)

else

S[0] := Chr(Len)

end;

procedure SetString(var Dst: string; Src: PChar; Len: Integer);

begin

if Len > 255 then

Move(Src^, Dst[1], 255)

else

Move(Src^, Dst[1], Len);

SetLength(Dst, Len);

end;

{$ENDIF}

end.