hashfile: avoid being fine with informative-grade hashes only

src/hash.h

@@ -53,6 +53,10 @@ public:
 
 	typedef std::map<std::string, factoryof<hash_proc>*> suite_t;
 	static suite_t& suite();
+
+	virtual bool cryptographically_significant() {
+		return true;
+	}
 };
 
 #endif

src/hashfile.cpp

@@ -62,6 +62,10 @@ public:
 		}
 		return r;
 	}
+
+	bool cryptographically_significant() {
+		return false;
+	}
 };
 
 /*
@@ -164,7 +168,8 @@ int hashfile::verify (istream&in)
 			continue;
 		}
 		if (i->second == hm[i->first]->finish()) {
-			++ok;
+			//avoid doing a positive decision on informative-grade-only hashes
+			if (hm[i->first]->cryptographically_significant()) ++ok;
 			err ("hash verification: ;-) "
 			     << i->first << " is GOOD");
 		} else {