Add == and != operators for multipart_t

Closes #512

tests/multipart.cpp

@@ -75,6 +75,21 @@ TEST_CASE("multipart legacy test", "[multipart]")
     assert(ok);
     assert(copy.equal(&multipart));
 
+    // Test equality operators
+    assert(copy == multipart);
+    assert(multipart == copy);
+
+    multipart.pop();
+
+    assert(copy != multipart);
+    assert(multipart != copy);
+
+    multipart_t emptyMessage1 {};
+    multipart_t emptyMessage2 {};
+
+    assert(emptyMessage1 == emptyMessage2);
+    assert(emptyMessage2 == emptyMessage1);
+
     multipart.clear();
     assert(multipart.empty());
 

zmq_addon.hpp

@@ -612,16 +612,26 @@ class multipart_t
     }
 
     // Check if equal to other multipart
-    bool equal(const multipart_t *other) const
+    bool equal(const multipart_t *other) const ZMQ_NOTHROW
     {
-        if (size() != other->size())
+        return *this == *other;
+    }
+
+    bool operator==(const multipart_t &other) const ZMQ_NOTHROW
+    {
+        if (size() != other.size())
             return false;
         for (size_t i = 0; i < size(); i++)
-            if (*peek(i) != *other->peek(i))
+            if (at(i) != other.at(i))
                 return false;
         return true;
     }
 
+    bool operator!=(const multipart_t &other) const ZMQ_NOTHROW
+    {
+        return !(*this == other);
+    }
+
 #ifdef ZMQ_CPP11
 
     // Return single part message_t encoded from this multipart_t.