为剩余字节添加填充到十六进制字符串

Question

I never ever worked with Hex-strings in PHP (or whatever language). Now I'm wondering how I could add padding to a hex string with 00 (in hex) up until it reaches 8 bytes.

$hex = bin2hex("MAIN");

How can I add 00 for the remaining bytes so that $hex holds 8 bytes?

Answer 1

Maybe try str_pad :

$hex = str_pad(bin2hex("MAIN"), 16, '00', STR_PAD_LEFT);

Output : "000000004d41494e"

Is that what you want ?