CODEWITHSUNDEEP
phphexbyte
Enid
Enid

Reputation: 23

How to convert Hex to binary in PHP?

I'm trying to send 0x01 HEX as Byte using the socket_write($socket, XXXX , 1); function.

There is part of documentation:

"...If yes, server will reply to module 0x01, if not – replay 0x00. Server must send answer – 1 Byte in HEX format."

Upvotes: 2

Views: 15117

Answers (1)

mario
mario

Reputation: 145482

There are multiple alternatives:

  • When using the pack() function, the string argument to the H* format specifier should not include the 0x prefix.

    pack("H*", "01")

  • To convert a single hex-number into a byte you can also use chr().

    chr(0x01)

    Here PHP first interprets the hex-literal 0x01 into a plain integer 1, while chr() converts it into a string. The reversal (for socket reading) is ord().

  • The most prevalent alternative is using just using C-string escapes:

    "\x01"

    Or in octal notation:

    "\001"

  • hex2bin("01") works just like pack("H*") here. And there's bin2hex for the opposite direction.

Upvotes: 12

Related Questions