【发布时间】：2010-12-23 15:11:50
【问题描述】：
经过一番搜索，我发现了这个 youtube 风格的 url 生成器，它带有加密功能，可以隐藏原始 id……但是我希望能提高效率，因为它会被大量使用。到目前为止，我已经改进了 20%...谁能帮我改进更多。
这是原文：
function alphaID($in, $to_num = false, $pad_up = false, $passKey = null)
{
$index = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
if ($passKey !== null) {
// Although this function's purpose is to just make the
// ID short - and not so much secure,
// with this patch by Simon Franz (http://blog.snaky.org/)
// you can optionally supply a password to make it harder
// to calculate the corresponding numeric ID
for ($n = 0; $n<strlen($index); $n++) {
$i[] = substr( $index,$n ,1);
}
$passhash = hash('sha256',$passKey);
$passhash = (strlen($passhash) < strlen($index))
? hash('sha512',$passKey)
: $passhash;
for ($n=0; $n < strlen($index); $n++) {
$p[] = substr($passhash, $n ,1);
}
array_multisort($p, SORT_DESC, $i);
$index = implode($i);
}
$base = strlen($index);
if ($to_num) {
// Digital number <<-- alphabet letter code
$in = strrev($in);
$out = 0;
$len = strlen($in) - 1;
for ($t = 0; $t <= $len; $t++) {
$bcpow = bcpow($base, $len - $t);
$out = $out + strpos($index, substr($in, $t, 1)) * $bcpow;
}
if (is_numeric($pad_up)) {
$pad_up--;
if ($pad_up > 0) {
$out -= pow($base, $pad_up);
}
}
} else {
// Digital number -->> alphabet letter code
if (is_numeric($pad_up)) {
$pad_up--;
if ($pad_up > 0) {
$in += pow($base, $pad_up);
}
}
$out = "";
for ($t = floor(log10($in) / log10($base)); $t >= 0; $t--) {
$a = floor($in / bcpow($base, $t));
$out = $out . substr($index, $a, 1);
$in = $in - ($a * bcpow($base, $t));
}
$out = strrev($out); // reverse
}
return $out;
}
这是我目前修改的代码：
function alphaID($in, $to_num = false, $pad_up = false, $passKey = null)
{
$index = 'abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
$i = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z');
if ($passKey !== null) {
// Although this function's purpose is to just make the
// ID short - and not so much secure,
// with this patch by Simon Franz (http://blog.snaky.org/)
// you can optionally supply a password to make it harder
// to calculate the corresponding numeric ID
$len = strlen($index);
$passhash = hash('sha256',$passKey);
$passhash = (strlen($passhash) < $len)
? hash('sha512',$passKey)
: $passhash;
for ($n=0; $n < $len; $n++) {
$p[] = substr($passhash, $n ,1);
}
array_multisort($p, SORT_DESC, $i);
$index = implode($i);
}
$base = strlen($index);
if ($to_num) {
// Digital number <<-- alphabet letter code
$in = strrev($in);
$out = 0;
$len = strlen($in) - 1;
for ($t = 0; $t <= $len; $t++) {
$bcpow = bcpow($base, $len - $t);
$out = $out + strpos($index, substr($in, $t, 1)) * $bcpow;
}
if (is_numeric($pad_up)) {
$pad_up--;
if ($pad_up > 0) {
$out -= pow($base, $pad_up);
}
}
} else {
// Digital number -->> alphabet letter code
if (is_numeric($pad_up)) {
$pad_up--;
if ($pad_up > 0) {
$in += pow($base, $pad_up);
}
}
$out = "";
for ($t = floor(log10($in) / log10($base)); $t >= 0; $t--) {
$a = floor($in / bcpow($base, $t));
$out = $out . substr($index, $a, 1);
$in = $in - ($a * bcpow($base, $t));
}
$out = strrev($out); // reverse
}
return $out;
}
你看不出有什么大的区别，只是我从 for 循环中删除了 strlen 并将其存储在一个变量中，并为索引预先计算了数组（有点笨拙......但是数组生成是组成大部分计算）。
应得的信用：这是原始作者信息： * @作者凯文·范·佐内维尔德 * @作者西蒙弗兰兹 * @copyright 2008 Kevin van Zonneveld (kevin dot vanzonneveld dot net) * @license www dot opensource dot org/licenses/bsd-license dot php 新 BSD 许可证 * @version SVN：发布：$Id：alphaID.inc.php 344 2009-06-10 17:43:59Z kevin $ * @link kevin dot vanzonneveld dot net
我不能发布网址，因为我的声誉很低：S
【问题讨论】：
-
您是否尝试过分析此代码（使用例如 XDebug）来查找瓶颈？我还没有发现任何直接影响性能的因素。
标签： php performance