PHP unpack() 函数
PHP unpack() 函数
定义和用法
unpack() 函数从二进制字符串对数据进行解包。
语法
unpack(format,data)
| 参数 | 描述 |
|---|---|
| format | 必需。规定在解包数据时所使用的格式。 |
| data | 可选。规定被解包的二进制数据。 |
format 参数的可能值：
- a – NUL-padded string
- A – SPACE-padded string
- h – Hex string, low nibble first
- H – Hex string, high nibble first
- c – signed char
- C – unsigned char
- s – signed short (always 16 bit, machine byte order)
- S – unsigned short (always 16 bit, machine byte order)
- n – unsigned short (always 16 bit, big endian byte order)
- v – unsigned short (always 16 bit, little endian byte order)
- i – signed integer (machine dependent size and byte order)
- I – unsigned integer (machine dependent size and byte order)
- l – signed long (always 32 bit, machine byte order)
- L – unsigned long (always 32 bit, machine byte order)
- N – unsigned long (always 32 bit, big endian byte order)
- V – unsigned long (always 32 bit, little endian byte order)
- f – float (machine dependent size and representation)
- d – double (machine dependent size and representation)
- x – NUL byte
- X – Back up one byte
- @ – NUL-fill to absolute position
实例
例子 1
<?php$data = "PHP";print_r(unpack("C*",$data));?>
输出：
Array([1] => 80[2] => 72[3] => 80)
例子 2
<?php$data = "PHP";print_r(unpack("C*myint",$data));?>
输出：
Array([myint1] => 80[myint2] => 72[myint3] => 80)
例子 3
<?php$bin = pack("c2n2",0x1234,0x5678,65,66);print_r(unpack("c2chars/n2int",$bin));?>
输出：
Array([chars1] => 52[chars2] => 120[int1] => 65[int2] => 66)