function _setupInlineCrypt()
{
$lambda_functions =& self::_getLambdaFunctions();
// The first 10 generated $lambda_functions will use the $keys hardcoded as integers
// for the mixing rounds, for better inline crypt performance [~20% faster].
// But for memory reason we have to limit those ultra-optimized $lambda_functions to an amount of 10.
// (Currently, for Crypt_RC2, one generated $lambda_function cost on php5.5@32bit ~60kb unfreeable mem and ~100kb on php5.5@64bit)
$gen_hi_opt_code = (bool) (count($lambda_functions) < 10);
// Generation of a unique hash for our generated code
$code_hash = "Crypt_RC2, {$this->mode}";
if ($gen_hi_opt_code) {
$code_hash = str_pad($code_hash, 32) . $this->_hashInlineCryptFunction($this->key);
}
// Is there a re-usable $lambda_functions in there?
// If not, we have to create it.
if (!isset($lambda_functions[$code_hash])) {
// Init code for both, encrypt and decrypt.
$init_crypt = '$keys = $self->keys;';
switch (true) {
case $gen_hi_opt_code:
$keys = $this->keys;
default:
$keys = array();
foreach ($this->keys as $k => $v) {
$keys[$k] = '$keys[' . $k . ']';
}
}
// $in is the current 8 bytes block which has to be en/decrypt
$encrypt_block = $decrypt_block = '
$in = unpack("v4", $in);
$r0 = $in[1];
$r1 = $in[2];
$r2 = $in[3];
$r3 = $in[4];
';
// Create code for encryption.
$limit = 20;
$actions = array($limit => 44, 44 => 64);
$j = 0;
for (;;) {
// Mixing round.
$encrypt_block .= '
$r0 = (($r0 + ' . $keys[$j++] . ' +
((($r1 ^ $r2) & $r3) ^ $r1)) & 0xFFFF) << 1;
$r0 |= $r0 >> 16;
$r1 = (($r1 + ' . $keys[$j++] . ' +
((($r2 ^ $r3) & $r0) ^ $r2)) & 0xFFFF) << 2;
$r1 |= $r1 >> 16;
$r2 = (($r2 + ' . $keys[$j++] . ' +
((($r3 ^ $r0) & $r1) ^ $r3)) & 0xFFFF) << 3;
$r2 |= $r2 >> 16;
$r3 = (($r3 + ' . $keys[$j++] . ' +
((($r0 ^ $r1) & $r2) ^ $r0)) & 0xFFFF) << 5;
$r3 |= $r3 >> 16;';
if ($j === $limit) {
if ($limit === 64) {
break;
}
// Mashing round.
$encrypt_block .= '
$r0 += $keys[$r3 & 0x3F];
$r1 += $keys[$r0 & 0x3F];
$r2 += $keys[$r1 & 0x3F];
$r3 += $keys[$r2 & 0x3F];';
$limit = $actions[$limit];
}
}
$encrypt_block .= '$in = pack("v4", $r0, $r1, $r2, $r3);';
// Create code for decryption.
$limit = 44;
$actions = array($limit => 20, 20 => 0);
$j = 64;
for (;;) {
// R-mixing round.
$decrypt_block .= '
$r3 = ($r3 | ($r3 << 16)) >> 5;
$r3 = ($r3 - ' . $keys[--$j] . ' -
((($r0 ^ $r1) & $r2) ^ $r0)) & 0xFFFF;
$r2 = ($r2 | ($r2 << 16)) >> 3;
$r2 = ($r2 - ' . $keys[--$j] . ' -
((($r3 ^ $r0) & $r1) ^ $r3)) & 0xFFFF;
$r1 = ($r1 | ($r1 << 16)) >> 2;
$r1 = ($r1 - ' . $keys[--$j] . ' -
((($r2 ^ $r3) & $r0) ^ $r2)) & 0xFFFF;
$r0 = ($r0 | ($r0 << 16)) >> 1;
$r0 = ($r0 - ' . $keys[--$j] . ' -
((($r1 ^ $r2) & $r3) ^ $r1)) & 0xFFFF;';
if ($j === $limit) {
if ($limit === 0) {
break;
}
// R-mashing round.
$decrypt_block .= '
$r3 = ($r3 - $keys[$r2 & 0x3F]) & 0xFFFF;
$r2 = ($r2 - $keys[$r1 & 0x3F]) & 0xFFFF;
$r1 = ($r1 - $keys[$r0 & 0x3F]) & 0xFFFF;
$r0 = ($r0 - $keys[$r3 & 0x3F]) & 0xFFFF;';
$limit = $actions[$limit];
}
}
$decrypt_block .= '$in = pack("v4", $r0, $r1, $r2, $r3);';
// Creates the inline-crypt function
$lambda_functions[$code_hash] = $this->_createInlineCryptFunction(array('init_crypt' => $init_crypt, 'encrypt_block' => $encrypt_block, 'decrypt_block' => $decrypt_block));
}
// Set the inline-crypt function as callback in: $this->inline_crypt
$this->inline_crypt = $lambda_functions[$code_hash];
}