Provide TfLiteOpaqueContextAddTensors, an API to add additional ten…

…sors to a supplied context.

This functionality is used by existing delegates, e.g.: https://github.com/tensorflow/tensorflow/blob/master/tensorflow/lite/delegates/nnapi/nnapi_delegate.cc that aren't using the opaque delegate API.

PiperOrigin-RevId: 553726768

tensorflow/lite/core/c/c_api_opaque.cc

@@ -456,6 +456,17 @@ TfLiteStatus TfLiteOpaqueContextGetNodeInitDataMmapInfo(
                                            custom_initial_data_size);
 }
 
+TfLiteStatus TfLiteOpaqueContextAddTensors(TfLiteOpaqueContext* context,
+                                           int tensors_to_add,
+                                           int* first_new_tensor_index) {
+  if (tensors_to_add <= 0) {
+    return kTfLiteError;
+  }
+  auto* tflite_context = Convert(context);
+  return tflite_context->AddTensors(tflite_context, tensors_to_add,
+                                    first_new_tensor_index);
+}
+
 void TfLiteOpaqueContextReportError(struct TfLiteOpaqueContext* opaque_context,
                                     const char* format, ...) {
   va_list vlist;

tensorflow/lite/core/c/c_api_opaque.h

@@ -500,6 +500,17 @@ TfLiteStatus TfLiteOpaqueContextGetNodeInitDataMmapInfo(
     int64_t* custom_initial_data_offset_in_file,
     int64_t* custom_initial_data_size);
 
+// Add 'tensors_to_add' tensors, preserving pre-existing Tensor entries.  If
+// non-null, the value pointed to by 'first_new_tensor_index' will be set to
+// the index of the first new tensor.  Returns 'kTfLiteOk' when the tensors have
+// been added successfully.  Returns 'kTfLiteError' in case of failure. Suppling
+// a value equal to or smaller than 0 for 'tensors_to_add' will result in
+// 'kTfLiteError' being returned.
+TFL_CAPI_EXPORT
+TfLiteStatus TfLiteOpaqueContextAddTensors(TfLiteOpaqueContext* context,
+                                           int tensors_to_add,
+                                           int* first_new_tensor_index);
+
 /// Reports an error message formed by using the provided 'format' string in
 /// combination with the data provided via the unnamed arguments following
 /// the 'format' parameter ('...').  The intended usage and behavior is the same

tensorflow/lite/core/c/c_api_test.cc

@@ -1538,6 +1538,33 @@ TEST(CApiSimple, OpaqueApiAccessors) {
           EXPECT_STREQ(kSubgraphName,
                        TfLiteOpaqueContextGetName(opaque_context));
           EXPECT_EQ(4, TfLiteOpaqueContextGetNumTensors(opaque_context));
+
+          int first_new_tensor_index = -1;
+          EXPECT_EQ(kTfLiteOk, TfLiteOpaqueContextAddTensors(
+                                   opaque_context, 1, &first_new_tensor_index));
+          EXPECT_EQ(5, TfLiteOpaqueContextGetNumTensors(opaque_context));
+          EXPECT_EQ(4, first_new_tensor_index);
+          TfLiteOpaqueTensor* new_tensor = TfLiteOpaqueContextGetOpaqueTensor(
+              opaque_context, first_new_tensor_index);
+          EXPECT_NE(new_tensor, nullptr);
+
+          EXPECT_EQ(kTfLiteOk, TfLiteOpaqueContextAddTensors(
+                                   opaque_context, 2, &first_new_tensor_index));
+          EXPECT_EQ(7, TfLiteOpaqueContextGetNumTensors(opaque_context));
+          EXPECT_EQ(5, first_new_tensor_index);
+          new_tensor = TfLiteOpaqueContextGetOpaqueTensor(
+              opaque_context, first_new_tensor_index);
+          EXPECT_NE(new_tensor, nullptr);
+          new_tensor = TfLiteOpaqueContextGetOpaqueTensor(
+              opaque_context, first_new_tensor_index + 1);
+          EXPECT_NE(new_tensor, nullptr);
+
+          EXPECT_EQ(kTfLiteError,
+                    TfLiteOpaqueContextAddTensors(opaque_context, 0,
+                                                  &first_new_tensor_index));
+          EXPECT_EQ(kTfLiteError,
+                    TfLiteOpaqueContextAddTensors(opaque_context, -1,
+                                                  &first_new_tensor_index));
           EXPECT_EQ(-1,
                     TfLiteOpaqueTensorNumDims(
                         TfLiteOpaqueContextGetOpaqueTensor(opaque_context, 3)));