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run code in 150+ php & hhvm versions
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<?php /** strrev function implementation taken from ext/standard/string.c PHP-5-5 branch http://lxr.php.net/xref/PHP_5_5/ext/standard/string.c#3165 // {{{ proto string strrev(string str) // Reverse a string PHP_FUNCTION(strrev) { char *str; char *e, *n, *p; int str_len; if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) == FAILURE) { return; } n = emalloc(str_len+1); p = n; e = str + str_len; while (--e>=str) { *p++ = *e; } *p = '\0'; RETVAL_STRINGL(n, str_len, 0); } // }}} */ // PHP Implementation function userland_strrev($string) { if (!is_string($string)) { return false; } $new_string = ""; $len = strlen($string); while (--$len > -1) { $new_string .= $string[$len]; } return $new_string; } $string = "Hello PHP!"; $c = 1000; $results = array(); $tests = array('strrev', 'userland_strrev'); foreach ($tests as $test) { for ($i = 0; $i < $c; $i++) { $t = microtime(true); $test($string); $results[$test][] = microtime(true) - $t; } $avg = array_sum($results[$test]) / count($results[$test]); printf("Average cost for function $test: %.6f ms\n", $avg); }
Output for 5.5.26, 5.5.28 - 5.5.30, 5.5.32, 5.5.34, 5.6.8 - 5.6.10, 5.6.13, 5.6.16, 5.6.18 - 5.6.19, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
Average cost for function strrev: 0.000000 ms Average cost for function userland_strrev: 0.000001 ms
Output for 5.2.0 - 5.2.9, 5.3.0, 5.3.4, 5.3.6, 5.3.10 - 5.3.13, 5.3.16, 5.3.18 - 5.3.25, 5.3.29, 5.4.3, 5.4.5, 5.4.9 - 5.4.12, 5.4.16, 5.4.19, 5.4.21 - 5.4.29, 5.4.31 - 5.4.32, 5.4.35, 5.4.39 - 5.4.40, 5.4.42, 5.5.24 - 5.5.25, 5.5.27, 5.5.31, 5.5.33, 5.5.35, 5.6.11 - 5.6.12, 5.6.14 - 5.6.15, 5.6.17, 5.6.20 - 5.6.28
Average cost for function strrev: 0.000000 ms Average cost for function userland_strrev: 0.000002 ms
Output for 5.4.45
Average cost for function strrev: 0.000000 ms Average cost for function userland_strrev: 0.000006 ms
Output for 5.4.44
Average cost for function strrev: 0.000000 ms Average cost for function userland_strrev: 0.000005 ms
Output for 5.1.0 - 5.1.6, 5.2.12 - 5.2.13, 5.3.5, 5.3.17, 5.4.30, 5.4.38, 5.4.43
Average cost for function strrev: 0.000000 ms Average cost for function userland_strrev: 0.000003 ms
Output for 5.3.7, 5.3.15, 5.3.27 - 5.3.28, 5.4.0 - 5.4.2, 5.4.4, 5.4.6 - 5.4.8, 5.4.13 - 5.4.15, 5.4.17 - 5.4.18, 5.4.20, 5.4.37, 5.4.41
Average cost for function strrev: 0.000001 ms Average cost for function userland_strrev: 0.000003 ms
Output for 5.0.3, 5.2.17, 5.3.2, 5.3.8, 5.3.14, 5.4.34, 5.4.36
Average cost for function strrev: 0.000001 ms Average cost for function userland_strrev: 0.000004 ms
Output for 5.3.1, 5.3.3, 5.3.9, 5.3.26
Average cost for function strrev: 0.000001 ms Average cost for function userland_strrev: 0.000002 ms
Output for 4.3.1 - 4.3.2, 4.3.4 - 4.3.8, 4.4.0 - 4.4.1, 4.4.4 - 4.4.6, 5.2.10, 5.2.16
Average cost for function strrev: 0.000001 ms Average cost for function userland_strrev: 0.000006 ms
Output for 4.3.10, 4.4.2, 4.4.7 - 5.0.2, 5.0.4 - 5.0.5, 5.2.11, 5.2.15
Average cost for function strrev: 0.000001 ms Average cost for function userland_strrev: 0.000005 ms
Output for 4.3.9, 5.2.14
Average cost for function strrev: 0.000001 ms Average cost for function userland_strrev: 0.000007 ms
Output for 4.3.0, 4.3.11, 4.4.3
Average cost for function strrev: 0.000002 ms Average cost for function userland_strrev: 0.000007 ms
Output for 4.3.3
Average cost for function strrev: 0.000003 ms Average cost for function userland_strrev: 0.000006 ms