perl 邮件解析及数据库操作
#!/usr/bin/perl# file: readmail01.pl
# Figure 7.4: An readmail program
#-------------------------------------Sub decode_mimewords---------------------------------
sub decode_mimewords {
my $encstr = shift;#省略@_,完整shift @_; #此处@_是所有传入参数组成的list
my %params = @_;#hash
my @tokens;#list
$@ = ''; # error-return
# Collapse boundaries between adjacent encoded words:
$encstr =~ s{(\?\=)[\r\n \t]*(\=\?)}{$1$2}gs;#把$encstr 替换s///第一个（）为$1第二个为$2
pos($encstr) = 0;#返回最后一次模式匹配的位置
### print STDOUT "ENC = [", $encstr, "]\n";
# Decode:
my ($charset, $encoding, $enc, $dec);
while (1) {
last if (pos($encstr) >= length($encstr));#Perl提供了last、next和redo这几个语句来控制代码块内的执行流程。last语句退出代码块； next语句终止当前指令然后开始下一循环；而redo语句则重新开始循环代码块却并不重新计算条件语句
my $pos = pos($encstr); # save it
# Case 1: are we looking at "=?..?..?="?
if ($encstr =~ m{\G # from where we left off..
=\?([^?]*) # "=?" + charset +
\?() #"?" + encoding +
\?([^?]+) #"?" + data maybe with spcs +
\?= #"?="
}xgi) {
($charset, $encoding, $enc) = ($1, lc($2), $3);
$dec = (($encoding eq 'q') ? _decode_Q($enc) : decode_base64($enc));
push @tokens, [$dec, $charset];#在数组末尾增加一个或多个元素。等价于slice (@array, @array, 0, elements);
next;
}
# Case 2: are we looking at a bad "=?..." prefix?
# We need this to detect problems for case 3, which stops at "=?":
pos($encstr) = $pos; # reset the pointer.
if ($encstr =~ m{\G=\?}xg) {
$@ .= qq|unterminated "=?..?..?=" in "$encstr" (pos $pos)\n|;
push @tokens, ['=?'];
next;
}
# Case 3: are we looking at ordinary text?
pos($encstr) = $pos; # reset the pointer.
if ($encstr =~ m{\G # from where we left off...
([\x00-\xFF]*? # shortest possible string,
\n*) # followed by 0 or more NLs,
(?=(\Z|=\?)) # terminated by "=?" or EOS
}xg) {
length($1) or die "MIME::Words: internal logic err: empty token\n";
push @tokens, [$1];
next;
}
# Case 4: bug!
die "MIME::Words: unexpected case:\n($encstr) pos $pos\n\t".
"Please alert developer.\n";
}
return (wantarray ? @tokens : join('',map {$_->} @tokens));
}
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