Implement stop place level comparison of IFOPT identifiers

Will be needed for Location comparison and Location merging.

autotests/ifopttest.cpp

@@ -44,6 +44,20 @@ private Q_SLOTS:
         QFETCH(bool, valid);
         QCOMPARE(IfoptUtil::isValid(ifopt), valid);
     }
+
+    void testStopPlace()
+    {
+        QCOMPARE(IfoptUtil::stopPlace(s("de:08115:4512:5:B")), s("de:08115:4512"));
+        QCOMPARE(IfoptUtil::stopPlace(s("de:08115:4512:5")), s("de:08115:4512"));
+        QCOMPARE(IfoptUtil::stopPlace(s("de:08115:4512")), s("de:08115:4512"));
+    }
+
+    void testIsSameStopPlace()
+    {
+        QVERIFY(IfoptUtil::isSameStopPlace(s("de:08115:4512:5:B"), s("de:08115:4512")));
+        QVERIFY(IfoptUtil::isSameStopPlace(s("de:08115:4512:5:B"), s("de:08115:4512:2:1")));
+        QVERIFY(!IfoptUtil::isSameStopPlace(s("de:08115:4512:5:B"), s("de:08115:4513:2:1")));
+    }
 };
 
 QTEST_APPLESS_MAIN(IfoptTest)

src/lib/ifopt/ifoptutil.cpp

@@ -30,3 +30,17 @@ bool IfoptUtil::isValid(QStringView ifopt)
 
     return elementCount >= 3 && elementCount <= 5 && ifopt[0].isLetter() && ifopt[1].isLetter() && ifopt[2] == QLatin1Char(':');
 }
+
+QStringView IfoptUtil::stopPlace(QStringView ifopt)
+{
+    qsizetype pos = 0;
+    for (int i = 0; i < 3; i++) {
+        pos = ifopt.indexOf(QLatin1Char(':'), pos) + 1;
+    }
+    return ifopt.left(pos - 1);
+}
+
+bool IfoptUtil::isSameStopPlace(QStringView lhs, QStringView rhs)
+{
+    return stopPlace(lhs) == stopPlace(rhs);
+}

src/lib/ifopt/ifoptutil.h

@@ -21,6 +21,12 @@ namespace IfoptUtil
 /** Check if @p ifopt is a valid IFOPT identifier. */
 bool isValid(QStringView ifopt);
 
+/** Returns the stop place identifier for the given (valid!) IFOPT identifier @p ifopt. */
+QStringView stopPlace(QStringView ifopt);
+
+/** Checks whether two valid IFOPT ids refer to the same stop place. */
+bool isSameStopPlace(QStringView lhs, QStringView rhs);
+
 }
 
 }