-Data - added a new duplicate method that will copy a data object but…

… continue to use it's memory if source

 data is Shared or Borrowed.  Allows copying a data object with shared data without making a copy of the actual data.

rutil/Data.cxx

@@ -663,6 +663,32 @@ Data::takeBuf(Data& other)
    return *this;
 }
 
+Data&
+Data::duplicate(const Data& other)
+{
+   if (&other == this)
+      return *this;
+
+   if (mShareEnum == Data::Take)
+      delete[] mBuf;
+
+   if (other.mBuf == other.mPreBuffer)
+   {
+      // plus one picks up the terminating safety NULL
+      memcpy(mPreBuffer, other.mPreBuffer, other.mSize + 1);
+      mBuf = mPreBuffer;
+   }
+   else
+   {
+      mBuf = other.mBuf;
+   }
+   mSize = other.mSize;
+   mCapacity = other.mCapacity;
+   mShareEnum = other.mShareEnum;
+
+   return *this;
+}
+
 Data&
 Data::copy(const char *buf, size_type length)
 {

rutil/Data.hxx

@@ -347,7 +347,15 @@ class Data
 
       /**
         Functional equivalent of: *this = Data(buf, length)
-        but avoid the intermediate allocation and free. Also,
+        and Data& copy(const char *buf, size_type length)
+        but avoids an actual copy of the data if {other} is Shared
+        or Borrowed.  Will have the same storage mode as {other}.
+      **/
+      Data& duplicate(const Data& other);
+
+      /**
+        Functional equivalent of: *this = Data(buf, length)
+        but avoids the intermediate allocation and free. Also,
         will never decrease capacity. Safe to call even if {buf}
         is part of {this}.