Tiaon Lab

On PHP’s MD5() documentation page, tszming at gmail dot com states by calling MD5() with raw_output option turned on and call bin2hex() function to convert it to hexadecimal is 3 times faster than using just MD5() function.

This sounds stupidly impossible, surely by calling one pre-built function should be faster than calling two pre-built functions with same functionality. But tszming is right, calling MD5 along is slower than calling bin2hex(md5()).

This is my test.

First test will create 1000 randomly generated string (ASCII 0 to 250). The test array of strings will be passed to the two functions to measure the time it takes to complete the operation.

Result:

Test Methods:

SimpleMD5 - Convert string to MD5 hash string using MD5 without raw_output option

	foreach ($test_array as $str) {
		$tmp[] = md5($str);
	}

BinMD5 - Convert string to MD5 hash string using tszming’s method, using raw_output option and use bin2hex() to convert them to hexadecimal.

	foreach ($test_array as $str) {
		$tmp[] = bin2hex(md5($str, true));
	}

Full Source Code:

Show Code | Download md5test.txt

Note: Test enviroment is PHP5 + Windows

While searching for “php benchmark”, I found PHP Benchmark test page. The first benchmark the page showed was foreach(), while(list()=each()) and loop using array_keys(). The test result was stated as “strange”. Loop using array_keys() function out performed the other loop techniques by 2 to 9 folds. Of cause, the test was done in a PHP4 enviroment. Since PHP5 was introduced, there has been a lot of performance increases, the test is out dated.

Eagerly wanting to know how this will perform in PHP5, I have written a set of similar tests to be tested on my PHP5+Windows machine. The result is as expected: completely different, loop using array_keys() is no longer the best performed loop in PHP5.

The test array is made randomly generated 8 characters long string keys and 64 characters long string values.

Test results:

Source code:

Loop 1: foreach() loop without fetching array key

Show Code

Loop 2: while(list()=each()) loop without fetching array key

Show Code

Loop 3: foreach() loop fetching array key

Show Code

Loop 4: while(list()=each()) loop fetching array key

Show Code

Loop 5: loop using array_keys()

Show Code

Full Source:

Show Code | Download looptest.txt

The mathmatically way
Explaination: We all know an even number is multiple of twos, and odd numbers are not. is_float is a PHP function test if $number divided by 2 is a whole number or not.

Show Code

Using bitwise operator
Explaination: In PHP & or AND is a bitwise operator. When used it performs bitwise operation between two numbers. In the following example, the operator will test if the last bit of $number is 1. Thus successfully tests if $number is even or odd.

Show Code

Conclusion:: Use bitwise operator to test an number is odd or even is much faster than using the division method. More detailed instruction can be found here.