Can anyone see where the following routine is going wrong, it is part of
an encryption utility I am putting together where I need to convert an
array of bytes into a string representation, I'm using 2 character hex
strings which keeps it readable and suits the mechanism I am using.
I have this routine I found on the net (www.xploiter.com) which looked
like it would work but it keeps raising access violations:
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;
end;
The FillChar statement causes problems but even after removing that I
still hit AVs when I later try to FreeMem() the original ByteArray I
pass into the function, which makes me think the hHexStr is corrupting
memory somehow.
I therefore scrapped this approach and created the following which is
using format to hopefully speed up the string concatenation, but I
wonder if this is a much slower approach?
procedure ByteToHex(pByteArray: PBYTE; var HexStr: string; BufLength:
Integer);
var
i: integer;
begin
HexStr := '';
for i := 0 to BufLength do
begin
HexStr := format('%s%.2x', [HexStr, pByteArray^]);
inc(pByteArray);
end;
end;
It could be that neither method is that good. Initially this will only
be dealing with small chunks of data anyway but overtime there is a
possibility it will be usurped to work with larger traffic.
Michael Darling
Solutions Analyst/Developer
ROOM Solutions Ltd
mailto:[EMAIL PROTECTED]
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