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POphp - help improve the efficiency of this youtube style url generator
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copied!<p>After some searching I found this youtube style url generator with encryption to hide the original id... however I am hoping to improve the efficiency as it will be used a lot. So far I have improved it by 20%... can anyone help me improve it more.</p> <p>This is the original:</p> <pre><code>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 $out; } </code></pre> <p>Here is my modified code so far:</p> <pre><code>function alphaID($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; } </code></pre> <p>As you can see no major difference, only I removed the strlen from the for loops and stored it in a variable and precalculated the array for the index (a bit clumsy... but the array generation is what was making up the bulk of the computation).</p> <p>Credit where its due: here is the original authors info: * @author Kevin van Zonneveld * @author Simon Franz * @copyright 2008 Kevin van Zonneveld (kevin dot vanzonneveld dot net) * @license www dot opensource dot org/licenses/bsd-license dot php New BSD Licence * @version SVN: Release: $Id: alphaID.inc.php 344 2009-06-10 17:43:59Z kevin $ * @link kevin dot vanzonneveld dot net</p> <p>I can't post the url's as I have to low reputation :S</p>

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