1 files changed, 117 insertions, 0 deletions
diff --git a/tensorflow/contrib/lite/toco/graph_transformations/resolve_constant_pack.cc b/tensorflow/contrib/lite/toco/graph_transformations/resolve_constant_pack.cc
new file mode 100644
index 0000000000..e86616574d
--- /dev/null
+++ b/tensorflow/contrib/lite/toco/graph_transformations/resolve_constant_pack.cc
@@ -0,0 +1,117 @@
+/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#include <vector>
+
+#include "tensorflow/contrib/lite/toco/graph_transformations/graph_transformations.h"
+#include "tensorflow/contrib/lite/toco/model.h"
+#include "tensorflow/contrib/lite/toco/tooling_util.h"
+#include "tensorflow/core/platform/logging.h"
+
+namespace toco {
+
+namespace {
+
+template <ArrayDataType Type>
+void Pack(Model* model, PackOperator const& op) {
+  auto& output_array = model->GetArray(op.outputs[0]);
+  CHECK(output_array.data_type == Type);
+
+  // Create a buffer for the output array
+  std::vector<DataType<Type>>& output_data =
+      output_array.GetMutableBuffer<Type>().data;
+  output_data.resize(RequiredBufferSizeForShape(output_array.shape()));
+
+  // Pack inputs into buffer
+  CHECK_EQ(op.axis, 0) << "Packing only supported along first axis";
+  int dst_offset = 0;
+  for (int i = 0; i < op.inputs.size(); i++) {
+    // Append array data to output for each input array
+    const auto& input_array = model->GetArray(op.inputs[i]);
+    int input_size = RequiredBufferSizeForShape(input_array.shape());
+    memcpy(&output_data[dst_offset], &input_array.GetBuffer<Type>().data[0],
+           input_size * ElementSize(Type));
+    dst_offset += input_size;
+  }
+  CHECK_EQ(dst_offset, output_data.size());
+}
+
+}  // namespace
+
+bool ResolveConstantPack::Run(Model* model, std::size_t op_index) {
+  auto it = model->operators.begin() + op_index;
+  const auto* base_op = it->get();
+  if (base_op->type != OperatorType::kPack) {
+    return false;
+  }
+  const auto* op = static_cast<const PackOperator*>(base_op);
+
+  CHECK_GE(op->inputs.size(), 1);
+  CHECK_EQ(op->outputs.size(), 1);
+  auto& output_array = model->GetArray(op->outputs[0]);
+  if (output_array.data_type == ArrayDataType::kNone) {
+    // Yield until the output type has been set by PropagateArrayDataTypes
+    return false;
+  }
+
+  if (!output_array.has_shape()) {
+    // Yield until the output shape has been set by PropagateFixedShapes
+    return false;
+  }
+
+  for (const auto& input : op->inputs) {
+    if (!IsConstantParameterArray(*model, input)) {
+      // Yield if any input is mutable
+      return false;
+    }
+  }
+
+  int axis = op->axis;
+  if (axis < 0) {
+    // Handle negative axis
+    axis += model->GetArray(op->inputs[0]).shape().dims().size();
+  }
+  CHECK_EQ(axis, 0) << "Packing only supported along 0th axis";
+
+  CHECK(!output_array.buffer);
+  switch (output_array.data_type) {
+    case ArrayDataType::kFloat:
+      Pack<ArrayDataType::kFloat>(model, *op);
+      break;
+    case ArrayDataType::kUint8:
+      Pack<ArrayDataType::kUint8>(model, *op);
+      break;
+    case ArrayDataType::kInt32:
+      Pack<ArrayDataType::kInt32>(model, *op);
+      break;
+    case ArrayDataType::kInt64:
+      Pack<ArrayDataType::kInt64>(model, *op);
+      break;
+    default:
+      LOG(FATAL) << "Unsupported data type given to Pack op with output \""
+                 << op->outputs[0] << "\"";
+      break;
+  }
+
+  // Erase input arrays if no longer used
+  for (const auto& input : op->inputs) {
+    toco::DeleteArrayIfUsedOnce(input, model);
+  }
+
+  // Erase the operator
+  model->operators.erase(it);
+  return true;
+}
+
+}  // namespace toco