PERL打印收到的Socket消息

利用Perl的Select(),sysread()和syswrite()收到的消息将以二进制的形式存储到$buffer中，因此如果直接打印$buffer的内容将得到乱码。要将二进制内容转换为十六进制数串，则必须使用unpack()函数，即：

my $hexstr=unpack("H*",$buffer);

而此时如果打印$hexstr将得到一系列的十六进制数串（数串的长度是接收到的字节数的两倍），仍然难以阅读。因此，有必要将十六进制数串每两个数字进行拆分并加前缀“0x”以便阅读。此时需要借助正则表达式进行模式匹配，方法为:

my @msg=($hexstr =~ m/../g);

其中.用以匹配一个字符。

示例代码如下：

##################################################################
#               DumpMsg
#
# Dump received message in hex mode.
#
# Format: DumpMsg($type, $msglen, $msg);
#
# input:        $type= 'MSC' | 'BSC'
#               $msglen= msg length
#               $msg= received msg
#
# output:       Print received msg to stderr and log in hex type
##################################################################
sub DumpMsg {
    my $type=$_[0];
    my $msglen=$_[1];
    CoolMisc::coolprint("Received message from $type: $msglen bytes/n" );
    LogPrint("Received message from $type: $msglen bytes/n");
    # change the received message from bin to hex string.
    # my @msg=split(/../,unpack("H*", $_[2]),$msglen);
    my $tmp = unpack("H*", $_[2]);
    my @msg = ( $tmp =~ m/../g );
    # print the message to stdout and log file.
    for(my $i=0;$i<$msglen;$i++) {
        print "0x$msg[$i] ";
        syswrite($ROUTELOG,"0x$msg[$i] ");
        if ($i%8 ==7) {
            print "/n";
            syswrite($ROUTELOG,"/n");
        }
    }
    print "/n";
    syswrite($ROUTELOG,"/n");
}

参考文献：

1. Perl Doc-Data::Numbershttp://perl.active-venture.com/pod/perlfaq4-datanumber.html

2. Perl函数pack/unpack:http://hi.baidu.com/xemoaya/blog/item/7ea20008f8d23ed563d98660.html

3.How can I split a string into chunks of two characters each in Perl?