You probably want to use BC_MATH or that new-fangled thing like it if
you want to deal in INT larger than 32 bit.
Or you could buy 64-bit hardware.
On Mon, March 20, 2006 9:13 am, Bruce wrote:
> I am having trouble porting some code originally written in Borland
> Delphi
> to PHP. The Delphi code expects certain behavior on integer overflows
> that I
> can only duplicate on some PHP systems. For example:
>
> $BB = -2181087916;
> $AA = (int)$BB;
> $AA = intval($BB);
>
> On some systems, $AA will be (int)-2147483648, however, on most
> systems, $AA
> will be (int)2113879380, which is the same value truncated at 32 bits.
> It is
> this latter behavior that I need to properly port the Delphi code.
>
> Can someone suggest a way to do this that is consistent on all
> platforms?
> For reference, I am attaching the Delphi code and my PHP port.
>
> Thanks...
>
> --Bruce
>
> {quick (block) mixer routine}
> procedure MixBlock(const Matrix : T128bit; var Block; Encrypt :
> Boolean);
>
> const
> CKeyBox : array [False..True, 0..3, 0..2] of LongInt =
>
> (((0, 3, 1), (2, 1, 3), (1, 0, 2), (3, 2, 0)),
> ((3, 2, 0), (1, 0, 2), (2, 1, 3), (0, 3, 1)));
>
> var
> Blocks : array [0..1] of LongInt absolute Block;
> Work : LongInt;
> Right : LongInt;
> Left : LongInt;
>
> R : LongInt;
> AA, BB : LongInt;
> CC, DD : LongInt;
>
> begin
> Right := Blocks[0];
> Left := Blocks[1];
>
> for R := 0 to 3 do begin
> {transform the right side}
> AA := Right;
> BB := Matrix[CKeyBox[Encrypt, R, 0]];
>
> CC := Matrix[CKeyBox[Encrypt, R, 1]];
> DD := Matrix[CKeyBox[Encrypt, R, 2]];
>
> AA := AA + DD; DD := DD + AA; AA := AA xor (AA shr 7);
> BB := BB + AA; AA := AA + BB; BB := BB xor (BB shl 13);
>
> CC := CC + BB; BB := BB + CC; CC := CC xor (CC shr 17);
> DD := DD + CC; CC := CC + DD; DD := DD xor (DD shl 9);
>
> AA := AA + DD; DD := DD + AA; AA := AA xor (AA shr 3);
> BB := BB + AA; BB := BB xor (BB shl 7);
>
> CC := CC + BB;
> CC := CC xor (DD shr 15);
> DD := DD + CC;
> DD := DD xor (DD shl 11);
>
> Work := Left xor DD;
> Left := Right;
> Right := Work;
> end;
>
> Blocks[0] := Left;
>
> Blocks[1] := Right;
> end;
>
> Here is my PHP port:
>
> <?php
> function zeroFill($a, $b)
> {
> $z = hexdec(80000000);
> if ($z & $a)
> {
> $a >>= 1;
> $a &= (~ $z);
> $a |= 0x40000000;
> $a >>= ($b-1);
> }
> else
> {
> $a >>= $b;
> }
> return $a;
> }
>
> function MixBlock($AKey, &$ACode, $Encrypt)
> {
> $CKeyBox = array(array(3, 2, 0), array(1, 0, 2), array( 2, 1, 3),
> array(0 ,
> 3, 1));
>
> $Right = $ACode[0];
> $Left = $ACode[1];
>
> for ($R=0; $R<= 3; $R++)
> {
> $AA = $Right;
> if ($Encrypt)
> {
> $BB = $AKey[$CKeyBox[ $R][0]];
> $CC = $AKey[$CKeyBox[ $R][1]];
> $DD = $AKey[$CKeyBox[ $R][2]];
> }
> else
> {
> $BB = $AKey[$CKeyBox[ 3-$R][0]];
> $CC = $AKey[$CKeyBox[ 3-$R][1]];
> $DD = $AKey[$CKeyBox[ 3-$R][2]];
> }
>
> $AA = (int)$AA + (int)$DD;
> $DD = (int)$DD + (int)$AA;
> $AA = (int)$AA ^ zeroFill( $AA, 7);
> $BB = (int)$BB + (int)$AA;
> $AA = (int)$AA + (int)$BB;
>
> $BB = (int)$BB ^ ((int)$BB << 13);
> $CC = (int)$CC + (int)$BB; $BB = (int)$BB + (int)$CC;
> $CC = (int)$CC ^ zeroFill( $CC, 17);
> $DD = (int)$DD + (int)$CC; $CC = (int)$CC + (int)$DD;
> $DD = (int)$DD ^ ((int)$DD << 9);
>
> $AA = (int)$AA + (int)$DD; $DD = (int)$DD + (int)$AA;
> $AA = (int)$AA ^ zeroFill( $AA, 3);
> $BB = (int)$BB + (int)$AA;
> $BB = (int)$BB ^ (int)((int)$BB << 7);
> $CC = (int)$CC + (int)$BB;
> $CC = (int)$CC ^ zeroFill( $DD, 15);
> $DD = (int)$DD + (int)$CC;
> $DD = (int)$DD ^ (int)((int)$DD << 11);
>
> $Work = $Left ^ $DD;
> $Left = $Right;
> $Right = $Work;
> }
>
> $ACode[0] = $Left;
> $ACode[1] = $Right;
> }
> ?>
>
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