Core: Provide comparison functions for QTypeRevision

The unspecified segment is between 0 and 1. This is because
QTypeRevision::zero(), as the default revisision needs to be smaller
than any other. At the same time we want explicitly specified non-zero
revisions to be larger than unspecified ones. Breaking this down on a
per segment level gives us the order shown here.

Change-Id: I1cca12f1180eb6f77563fb5b22c3400e118dc5e9
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 36 insertions, 0 deletions

diff --git a/src/corelib/tools/qversionnumber.h b/src/corelib/tools/qversionnumber.h
index 16058bd04a..03a27548b8 100644
--- a/src/corelib/tools/qversionnumber.h
+++ b/src/corelib/tools/qversionnumber.h
@@ -416,6 +416,42 @@ inline constexpr bool operator!=(QTypeRevision lhs, QTypeRevision rhs)
     return lhs.toEncodedVersion<quint16>() != rhs.toEncodedVersion<quint16>();
 }
 
+inline constexpr bool operator<(QTypeRevision lhs, QTypeRevision rhs)
+{
+    return (!lhs.hasMajorVersion() && rhs.hasMajorVersion())
+            // non-0 major > unspecified major > major 0
+            ? rhs.majorVersion() != 0
+            : ((lhs.hasMajorVersion() && !rhs.hasMajorVersion())
+               // major 0 < unspecified major < non-0 major
+               ? lhs.majorVersion() == 0
+               : (lhs.majorVersion() != rhs.majorVersion()
+                  // both majors specified and non-0
+                  ? lhs.majorVersion() < rhs.majorVersion()
+                  : ((!lhs.hasMinorVersion() && rhs.hasMinorVersion())
+                     // non-0 minor > unspecified minor > minor 0
+                     ? rhs.minorVersion() != 0
+                     : ((lhs.hasMinorVersion() && !rhs.hasMinorVersion())
+                        // minor 0 < unspecified minor < non-0 minor
+                        ? lhs.minorVersion() == 0
+                        // both minors specified and non-0
+                        : lhs.minorVersion() < rhs.minorVersion()))));
+}
+
+inline constexpr bool operator>(QTypeRevision lhs, QTypeRevision rhs)
+{
+    return lhs != rhs && !(lhs < rhs);
+}
+
+inline constexpr bool operator<=(QTypeRevision lhs, QTypeRevision rhs)
+{
+    return lhs == rhs || lhs < rhs;
+}
+
+inline constexpr bool operator>=(QTypeRevision lhs, QTypeRevision rhs)
+{
+    return lhs == rhs || !(lhs < rhs);
+}
+
 Q_STATIC_ASSERT(sizeof(QTypeRevision) == 2);
 Q_DECLARE_TYPEINFO(QTypeRevision, Q_MOVABLE_TYPE);