phpseclib\Crypt\RC2::_setupInlineCrypt PHP Method

    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];
    }