1 files changed, 17 insertions, 2 deletions
diff --git a/vespajlib/src/main/java/com/yahoo/tensor/serialization/SparseBinaryFormat.java b/vespajlib/src/main/java/com/yahoo/tensor/serialization/SparseBinaryFormat.java
index 8ab23c8d77c..6b0443c9bfe 100644
--- a/vespajlib/src/main/java/com/yahoo/tensor/serialization/SparseBinaryFormat.java
+++ b/vespajlib/src/main/java/com/yahoo/tensor/serialization/SparseBinaryFormat.java
@@ -53,8 +53,15 @@ class SparseBinaryFormat implements BinaryFormat {
     }
 
     @Override
-    public Tensor decode(TensorType type, GrowableByteBuffer buffer) {
-        consumeAndValidateDimensions(type, buffer);
+    public Tensor decode(Optional<TensorType> optionalType, GrowableByteBuffer buffer) {
+        TensorType type;
+        if (optionalType.isPresent()) {
+            type = optionalType.get();
+            consumeAndValidateDimensions(optionalType.get(), buffer);
+        }
+        else {
+            type = decodeType(buffer);
+        }
         Tensor.Builder builder = Tensor.Builder.of(type);
         decodeCells(buffer, builder, type);
         return builder.build();
@@ -75,6 +82,14 @@ class SparseBinaryFormat implements BinaryFormat {
         }
     }
 
+    private TensorType decodeType(GrowableByteBuffer buffer) {
+        int numDimensions = buffer.getInt1_4Bytes();
+        TensorType.Builder builder = new TensorType.Builder();
+        for (int i = 0; i < numDimensions; ++i)
+            builder.mapped(buffer.getUtf8String());
+        return builder.build();
+    }
+
     private void decodeCells(GrowableByteBuffer buffer, Tensor.Builder builder, TensorType type) {
         int numCells = buffer.getInt1_4Bytes();
         for (int i = 0; i < numCells; ++i) {