Re: IntVal(float) Returns Different Values

You want the php-general mailing list. This list is for discussing development of the PHP language and runtime... Jasper 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; } ?>