PHP 5.6.3 此版本加入"q", "Q", "J",低于此版本均不能使用
#5.6.3 The "q", "Q", "J" and "P" codes were added to enable working with 64-bit numbers.
#5.5.0 The "Z" code was added with equivalent functionality to "a" for Perl compatibility.
参数列表
Code Description
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)
q signed long long (always 64 bit, machine byte order)
Q unsigned long long (always 64 bit, machine byte order)
J unsigned long long (always 64 bit, big endian byte order)
P unsigned long long (always 64 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
Z NUL-padded string (new in PHP 5.5)
@ NUL-fill to absolute position
关于Pack:
string pack ( string $format [, mixed $args [, mixed $... ]] )
下面的第一部分把数字值包装成字节:
$out = pack("CCCC", 65, 66, 67, 68); # $out 等于"ABCD"
$out = pack("C4", 65, 66, 67, 68); # 一样的东西
下面的对 Unicode 的循环字母做同样的事情:
$foo = pack("U4", 0x24b6, 0x24b7, 0x24b8, 0x24b9);
下面的做类似的事情,增加了一些空:
$out = pack("CCxxCC", 65, 66, 67, 68); # $out 等于 "AB\0\0CD"
打包你的短整数并不意味着你就可移植了:
$out = pack("s2", 1, 2);
# 在小头在前的机器上是 "\1\0\2\0"
# 在大头在前的机器上是 "\0\1\0\2"
在二进制和十六进制包装上,count 指的是位或者半字节的数量,而不是生成的字节数量:
$out = pack("B32", "...");
$out = pack("H8", "5065726c"); # 都生成“Perl”
a 域里的长度只应用于一个字串:
$out = pack("a4", "abcd", "x", "y", "z"); # "abcd"
要绕开这个限制,使用多倍声明:
$out = pack("aaaa", "abcd", "x", "y", "z"); # "axyz"
$out = pack("a" x 4, "abcd", "x", "y", "z"); # "axyz"
a 格式做空填充:
$out = pack("a14", "abcdefg"); # " abcdefg\0\0\0\0\0\0"
关于unpack:
array unpack ( string $format, string $data )
$data = "010000020007";
unpack("Sint1/Cchar1/Sint2/Cchar2",$data);
# array('int1'=>1, 'char1'=>'0','int2'=>2,'char2'=>7);
举例 协议格式如下:
包头(2bytes)+加密(1byte)+命令码(2bytes)+帧内容
1.包头的内容是记录帧内容的长度;
2.加密:0表示不加密,1表示加密;
3.命令码为服务端命令识别符号;
使用pack/unpack 举例程序代码为 :
$lastact = pack('SCSa32a32',0x0040, 0x00, 0x0006, $username, $passwd );
unpack('Sint1/Cchar1/Sint2/Cchar2/',$lastmessage);
感谢分享 参考资料
http://my.oschina.net/goal/blog/195749
http://www.03sec.com/3061.shtml
http://blog.sina.com.cn/s/blog_3eba8f1c0100nq9r.html
http://bbs.phpchina.com/thread-104492-1-1.html
http://www.neatstudio.com/show-2327-1.shtml