_php example of implementation method of PHP processing binary data

PHP processing binary data requires a pack () and unpack ().

Pack () is used to convert data into binary data, using the following methods:

Pack ("LL", 0,1);

Pack ("C", a);

Unpack () can parse binary data into a relational array that accepts 2 parameters, using the following method:

$arr = Unpack ("Chead", $binstream); Read 1th byte

$arr = Unpack ("Chead/c3string/c4number", $binstream); Read 8 bytes, with a slash to separate

The first parameter table for the pack () and unpack () functions is as follows

A:null-Filled byte string

A: space-filled byte string

H: Hexadecimal number, low four-bit byte first

H: Hexadecimal number, high four-bit byte first

C: Signed characters

C: Unsigned characters

S: signed short integer (always 16 bits, machine byte order)

S: unsigned short integer (always 16 bits, machine byte order)

N: unsigned short integer (always 16-bit, large-tailed byte-order)

V: unsigned short integer (always 16-bit, small-tailed byte-order)

I: Signed int (machine-related size and byte-order)

I: Unsigned int (machine-related size and byte-order)

L: Signed Long Integer (always 32 bits, machine byte order)

L: unsigned long int (always 32 bits, machine byte order)

N: unsigned long integer (always 32-bit, large-tailed byte order)

V: unsigned long integer (always 32-bit, small-tailed byte-order)

F: Floating-point numbers (machine-relative size and representation)

D: Double precision (machine-relative size and representation)

X: Empty bytes

X: Backwards One byte

@: Fill absolute position with null

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