Recently, as part of school course on optimization, I have identified a potential optimization or feature for PHP. After looking through the array.c file(located in etc/standard in the PHP source code), I noticed that both the in_array and array_search are using the linear search C function php_search_array. The potential issue I see is that even though the linear search algorithm does not drastically effect performance when searching a relatively small array, it may slow performance down when iterating through a very large array(couple of million indexes).
To back this fact up I preformed some benchmarks using a PHP script that measures the time it takes to preform a linear search and binary search. The benchmark was in favor of the binary search as it found its target many times quicker compared to the linear search. After researching more about different PHP search functions, I was not able to find one that uses a binary search algorithm. Based on these factors I believe that a binary search implementation into PHP will prove useful in certain situations and would like to implement that feature. At the moment I am debating between adding a separate binary search based function into array.c or modifying the current array_search_array function to utilize a binary search algorithm. Since the requirement for a binary search is that the array being searched is sorted, I thought is would be a good idea to have a Boolean parameter in the binary search function to specify if the input array should be sorted or not. something among the lines of "function binary_search(string target, array arrayToSearch, bool sort)". Doing this, the function can preform a sort if required to, thus not needing to sort a array that is already sorted. Before I can begin the implementation and create a pull request, I would like to know the PHP's community feedback on my potential contribution and if this is a wise feature to change or implement.
