Compare size before data when ordering cache bucket entries

This has the effect of significantly reducing actual string
comparisons, and should improve the performance of FindGrp
a bit, although it's hardly measureable (callgrind says it
uses 10% instructions less now).

1 files changed, 11 insertions, 0 deletions

diff --git a/apt-pkg/contrib/string_view.h b/apt-pkg/contrib/string_view.h
index f158ef8d6..c504edd27 100644
--- a/apt-pkg/contrib/string_view.h
+++ b/apt-pkg/contrib/string_view.h
@@ -112,6 +112,17 @@ public:
     constexpr size_t length() const { return size_; }
 };
 
+/**
+ * \brief Faster comparison for string views (compare size before data)
+ *
+ * Still stable, but faster than the normal ordering. */
+static inline int StringViewCompareFast(StringView a, StringView b) {
+    if (a.size() != b.size())
+        return a.size() - b.size();
+
+    return memcmp(a.data(), b.data(), a.size());
+}
+
 
 }