track primordial goo frontends

contrib/frontends/cpp/nntpchan-daemon/src/message.cpp

@@ -0,0 +1,29 @@
+#include "message.hpp"
+
+namespace nntpchan
+{
+  bool IsValidMessageID(const MessageID & msgid)
+  {
+    auto itr = msgid.begin();
+    auto end = msgid.end();
+    --end;
+    if (*itr != '<') return false;
+    if (*end != '>') return false;
+    bool atfound = false;
+    while(itr != end) {
+      auto c = *itr;
+      ++itr;
+      if(atfound && c == '@') return false;
+      if(c == '@') {
+        atfound = true;
+        continue;
+      }
+      if (c == '$' || c == '_' || c == '-') continue;
+      if (c > '0' && c < '9') continue;
+      if (c > 'A' && c < 'Z') continue;
+      if (c > 'a' && c < 'z') continue;
+      return false;
+    }
+    return true;
+  }
+}