socket 通信心得以及几个自己开发写的可复用函数 perl
在socket通信编程时，我们会往往假设TCP报文传输的排列是很紧密的，收完一个接着就是下一个，但是事实不是这样的。可能一般是紧密的，但是有个别情况出现，所以就出现了经典的接收信息的写法：以报头标量的总长度为条件，判断剩下的待接收内容的长度。下面是一个我自己定义的接收子函数：目的是从sock内接收$leng个长度的字符，返回读出的字符串变量：#### This function is made for returning one string that have being recieved accoding the length from the socket
sub recieve{
&log("Entering the recieve function");
my ($sock,$total);
($sock,$total) = @_;
my $ret;
my $len;
my $leng = $total;
&log($leng);
my $Str = "";
my $sum = 0;
while($total > 0){
my $buf = undef;
recv($$sock,$buf,$total,0);
$len = length($buf);
$total -= $len;
if($len > 0){
$Str = join( "", $Str, $buf);
$sum += $len;
}
&log($Str);
&log($sum);
}
if($leng == $sum){
$ret = $Str;
}else{
$ret = -1;
}
return $ret;
}
下面是一个自定义的函数目的是把一个数字转换成固定长度的字符串
#### This function is made for converting one $num to be a string whose length is $len
sub convert{
my($num,$len);
($num,$len)=@_;
my $str;
if(length($num) < $len ){
$str = join( "", $num, (" " x ($len - length($num))));
}
return $str;
}
下面的自定义函数目的是：把入参的各个字符串 转化成分别之前带有一个10位长度标志字符串变量的长度的字符串的拼接字符串
sub spell{
my $Str = "";
my $sum = 0;
foreach (@_){
my $len = length($_);
my $lenStr = &convert($len,10);
$Str = join("", $Str,$lenStr);
$sum += 10;
$Str = join("",$Str,$_);
$sum += $len;
}
my $sumStr = &convert($sum,20);
my $res = join("",$sumStr,$Str);
return $res;
}
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