How PHP handles binary data

How does PHP handle binary data? Today I will bring you an implementation method for processing binary data in PHP. Share it with everyone and give it as a reference. I hope to be helpful.

PHP needs to use pack() and unpack() to process binary data.

pack() is used to convert data into binary data. The usage method is as follows:

pack("LL", 0 ,1);

pack(“C”, a);

unpack() can parse binary data into a relational array. It accepts 2 parameters and is used as follows:

$arr ​​= unpack(“Chead”, $binstream); //Read the first byte

$arr ​​= unpack(“Chead/C3string/C4number”, $binstream); // Read 8 bytes, which can be separated by slashes

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

■a: NULL-filled byte string

■A: Space-filled byte string

■h: Hexadecimal number, low nibble first

■ H: Hexadecimal number, high nibble first

■c: Signed character

■C: Unsigned character

■s: Signed short (always 16 bits, machine byte order)

■S: Unsigned short (always 16 bits, machine byte order)

#■n: Unsigned short (always 16 bits, big-endian)

■v: Unsigned short (always 16 bit, little endian)

■I: signed integer (machine dependent size and endianness)

■I: unsigned integer (machine dependent Relevant size and endianness)

■l: signed long (always 32 bits, machine endianness)

■L: unsigned long Integer type (always 32 bits, machine byte order)

■N: Unsigned long integer type (always 32 bits, big endian byte order)

■V: Unsigned long (always 32 bits, little endian)

■f: Floating point (machine dependent size and representation)

■d: Double (machine dependent size and representation)

■x: Null byte

■X: Go back one byte

■@: Fill absolute positions with NULL

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