[luci/import] Revise CircleReader

This will revise CircleReader to provide direct file data access.

ONE-DCO-1.0-Signed-off-by: SaeHie Park <[email protected]>

compiler/luci/import/include/luci/Import/CircleReader.h

@@ -115,11 +115,19 @@ class CircleReader
 
 public:
   bool parse(const circle::Model *model);
+  bool parse(const circle::Model *model, const uint8_t *data, const size_t size);
   bool select_subgraph(uint32_t subgraph);
 
+public:
+  // to access raw file data for Buffer outside of flatbuffer range
+  const uint8_t *file_data(uint64_t offset) const;
+  size_t file_size(void) const { return _file_size; }
+
 private:
   const circle::Model *_model{nullptr};
   const circle::SubGraph *_current_subgraph{nullptr};
+  const uint8_t *_file_data{nullptr};
+  size_t _file_size{0};
 };
 
 } // namespace luci

compiler/luci/import/src/CircleReader.cpp

@@ -331,6 +331,21 @@ bool CircleReader::parse(const circle::Model *model)
   return true;
 }
 
+bool CircleReader::parse(const circle::Model *model, const uint8_t *data, const size_t size)
+{
+  assert(model != nullptr);
+  assert(data != nullptr);
+  assert(size > 0);
+
+  // for direct pointer access
+  _model = model;
+
+  _file_data = data;
+  _file_size = size;
+
+  return true;
+}
+
 bool CircleReader::select_subgraph(uint32_t sgindex)
 {
   if (num_subgraph() <= sgindex)
@@ -349,6 +364,15 @@ bool CircleReader::select_subgraph(uint32_t sgindex)
   return true;
 }
 
+// NOTE need caution not to access beyond _file_data + _file_size.
+// current method doesn't have this guard.
+const uint8_t *CircleReader::file_data(uint64_t offset) const
+{
+  assert(_file_data);
+  assert(offset < _file_size);
+  return (_file_data == nullptr) ? nullptr : _file_data + offset;
+}
+
 template <typename T>
 VectorWrapper<T>::VectorWrapper(const flatbuffers::Vector<T> *ptr) : _vector(ptr)
 {