Serializer improvements:

* Add getSlice()
* Make getVLDataLength public

src/ripple/protocol/Serializer.h

@@ -353,6 +353,15 @@ public:
     void
     getFieldID (int& type, int& name);
 
+    // Returns the size of the VL if the
+    // next object is a VL. Advances the iterator
+    // to the beginning of the VL.
+    int
+    getVLDataLength ();
+
+    Slice
+    getSlice (std::size_t bytes);
+
     // VFALCO DEPRECATED Returns a copy
     Blob
     getRaw (int size);
@@ -364,9 +373,6 @@ public:
     Buffer
     getVLBuffer();
 
-private:
-    int getVLDataLength ();
-
     template<class T>
     T getRawHelper (int size);
 };

src/ripple/protocol/impl/Serializer.cpp

@@ -575,6 +575,19 @@ int SerialIter::getVLDataLength ()
     return datLen;
 }
 
+Slice
+SerialIter::getSlice (std::size_t bytes)
+{
+    if (bytes > remain_)
+        throw std::runtime_error(
+            "invalid SerialIter getSlice");
+    Slice s(p_, bytes);
+    p_ += bytes;
+    used_ += bytes;
+    remain_ -= bytes;
+    return s;
+}
+
 // VFALCO DEPRECATED Returns a copy
 Blob
 SerialIter::getVL()