PHP unpack () function

PHP

Syntax:
array unpack ($format, $data, $offset)
Parameters:This function takes three parameters as above and described below:
  • $format:Required. Specifies the format to use when packing data.
    • a - denotes a NUL-padded string.
    • A - denotes a string with a space.
    • h - denotes the low half of the first hexadecimal line.
    • H - denotes the first high-cool hex string.
    • with - denotes a signed character.
    • C - denotes an unsigned character.
    • s - denotes signed short (16 bit machine byte order).
    • S - denotes an unsigned short (16 bit, machine byte order).
    • n - denotes an unsigned short (16 bit, big endian byte order).
    • v - denotes unsigned short (16-bit big endian byte order).
    • i - denotes a signed integer (machine dependent byte order and size).
    • I - denotes an unsigned integer (machine dependent byte order and size).
    • l - denotes a signed long character (32 bit machine byte order).
    • L - denotes unsigned long (32-bit, machine byte order).
    • N - denotes unsigned long (32 bit, big endian byte order).
    • V - denotes unsigned long (32-bit big endian byte sequence).
    • f - stands for float (machine-dependent representation and size).
    • d - stands for double (machine-dependent representation and size).
    • x - denotes NUL bytes.
    • X - denotes one byte backup.
    • Z - denotes a NUL-padded string.
    • @ - indicates NUL padding to an absolute position.
  • $data:Required. This specifies the binary data to be decompressed.
  • offset:This parameter contains the offset that starts with unpacking.
Returned value:Returns an associative array containing unpacked elements on success, or FALSE on failure.Note.This function is available for PHP 4.0.0 and later later versions.Example 1:This program uses the C format to decompress data from a binary string. var_dump (unpack ( "C *" , "GEEKSFORGEEKS" )); ?> Exit:
array (13 ) {[1] = > int (71) [2] = > int (69) [3] = > int (69) [4] = > int (75) [5] = > int (83) [6] = > int (70) [7] = > int (79) [8] = > int (82) [9] = > int (71) [10] = > int (69) [11] = > int (69) [12] = > int (75) [13] = > int (83)}
Example 2: $binary_data = pack ( "c2n2" , 0x1634, 0x3623, 65, 66); var_dump (unpack ( "c2chars / n2int" , $binary_data )); ?> Exit:
array (4 ) {["chars1"] = > int (52) ["chars2"] = > int (35) ["int1"] = > int (65) ["int2"] = > int (66)}
Example 3: Inthis example uses the i format to decompress data from a binary string. $binary_data = pack ( "i3" , 56, 49, 54); var_dump (unpack ( "i3" , $binary_data )); ?> Exit:
array (3 ) {[1] = > int (56) [2] = > int (49) [3] = > int (54)}
Help: https://www.php.net/manual/en/function.unpack.php



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