How can strlen () be implemented without using php internal functions?

How can strlen () be implemented without using php internal functions? How can strlen () be implemented without using php internal functions?

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How can strlen () be implemented without using php internal functions?

function mystrlen($str){   $i = 0;   while(1)if(!isset($str[$i++]))return $i-1;}

The efficiency is not high, so it can be improved. For example, the greatest coordinate can be found using isset in the binary method.

This is a little more efficient.

function mystrlen($str){   $i = -1;   while(1) if(!isset($str[++$i])) return $i;}

Function mystrlen ($ str) {$ size = 1024; // value range of 1024 for each test: $ count = 0; // number of times that the test meets the length $ length = $ size * $ count-1; // currently, you can determine the length of the string while (isset ($ str [$ length + $ size]) {// test, 2047, 3071,4095 ...... $ Count = $ count + 1; $ length = $ length + $ size;} $ low = 0; // Binary Search bottom boundary $ high = $ size-1; // The second part searches for the upper boundary while ($ low <= $ high) {$ mid = floor ($ low + $ high)/2 ); if (isset ($ str [$ length + $ mid]) &! Isset ($ str [$ length + $ mid + 1]) {return $ length + $ mid + 1;} if (! Isset ($ str [$ length + $ mid]) {$ high = $ mid-1;} if (isset ($ str [$ length + $ mid]) {$ low = $ mid + 1 ;}}}

// The method in the other answers above, a 2 m string needs to be cyclically 2 million times.
// This is not the best solution, but it also reduces the 2 m string loop to more than 2000 times.
// PHP saves the string with a length when saving it. You don't have to worry about it. You can use native functions to retrieve it easily. Why.