Add ParseHeaders() to library.

Signed-off-by: Thomas Hochstein <thh@thh.name>

lib/NewsStats.pm

@@ -2,7 +2,7 @@
 #
 # Library functions for the NewsStats package.
 #
-# Copyright (c) 2010-2013 Thomas Hochstein <thh@thh.name>
+# Copyright (c) 2010-2013, 2025 Thomas Hochstein <thh@thh.name>
 #
 # This module can be redistributed and/or modified under the same terms under
 # which Perl itself is published.
@@ -34,6 +34,7 @@ require Exporter;
   ListNewsgroups
   ParseHierarchies
   ReadGroupList
+  ParseHeaders
   OutputData
   FormatOutput
   SQLHierarchies
@@ -254,6 +255,42 @@ sub ReadGroupList {
   return \%ValidGroups;
 };
 
+################################################################################
+sub ParseHeaders {
+################################################################################
+### return a hash of all headers (ignoring duplicate headers)
+### parsed from raw headers
+### -> taken and modified from pgpverify
+### -> Written April 1996, <tale@isc.org> (David C Lawrence)
+### -> Currently maintained by Russ Allbery <eagle@eyrie.org>
+### IN : $RawHeaders : raw headers as found in posting
+### OUT: %Headers    : hash containing header contents,
+###                    keyed by lower-case header name
+  my (%Header, $Label, $Value);
+  foreach (@_) {
+    s/\r?\n$//;
+
+    last if /^$/;
+
+    if (/^(\S+):[ \t](.+)/) {
+      ($Label, $Value) = ($1, $2);
+      # discard all duplicate headers
+      next if $Header{lc($Label)};
+      $Header{lc($Label)} = $Value;
+    } elsif (/^\s/) {
+      # continuation lines
+      if ($Label) {
+        $Header{lc($Label)} .= "\n$_";
+      } else {
+        warn (sprintf("Non-header line: %s\n",$_));
+      }
+    } else {
+      warn (sprintf("Non-header line: %s\n",$_));
+    }
+  }
+  return %Header;
+};
+
 ################################################################################
 
 #####----------------------------- TimePeriods ----------------------------#####