add < operator to UVarint (#57)

Signed-off-by: Alexey-N-Chernyshov <[email protected]>

Author: Alexey-N-Chernyshov

include/libp2p/multi/uvarint.hpp

@@ -67,6 +67,7 @@ namespace libp2p::multi {
 
     bool operator==(const UVarint& r) const;
     bool operator!=(const UVarint& r) const;
+    bool operator<(const UVarint& r) const;
 
     /**
      * @return the number of bytes currently stored in a varint

src/multi/uvarint.cpp

@@ -76,6 +76,10 @@ namespace libp2p::multi {
     return !(*this == r);
   }
 
+  bool UVarint::operator<(const UVarint &r) const {
+    return toUInt64() < r.toUInt64();
+  }
+
   size_t UVarint::calculateSize(gsl::span<const uint8_t> varint_bytes) {
     size_t size = 0;
     size_t shift = 0;