Add GetVectorData()

It's necessary to get data pointer from a vector sometimes.
This function will guarantee that the data pointer is nullptr
if the vector is empty.

Change-Id: I156308bcb193fe404452d3cd3b24b3f80c3c3727

diff --git a/vp9/simple_encode.cc b/vp9/simple_encode.cc
index 25d0251..d5e6fb5 100644 (file)
--- a/vp9/simple_encode.cc
+++ b/vp9/simple_encode.cc
@@ -789,6 +789,14 @@ void SimpleEncode::SetExternalGroupOfPicture(
   external_arf_indexes_ = external_arf_indexes;
 }
 
+template <typename T>
+T *GetVectorData(const std::vector<T> &v) {
+  if (v.empty()) {
+    return nullptr;
+  }
+  return const_cast<T *>(v.data());
+}
+
 void SimpleEncode::StartEncode() {
   assert(impl_ptr_->first_pass_stats.size() > 0);
   vpx_rational_t frame_rate =
@@ -797,7 +805,7 @@ void SimpleEncode::StartEncode() {
       vp9_get_encoder_config(frame_width_, frame_height_, frame_rate,
                              target_bitrate_, VPX_RC_LAST_PASS);
   vpx_fixed_buf_t stats;
-  stats.buf = impl_ptr_->first_pass_stats.data();
+  stats.buf = GetVectorData(impl_ptr_->first_pass_stats);
   stats.sz = sizeof(impl_ptr_->first_pass_stats[0]) *
              impl_ptr_->first_pass_stats.size();
 
@@ -808,7 +816,7 @@ void SimpleEncode::StartEncode() {
                 frame_height_, 1);
   frame_coding_index_ = 0;
   encode_command_set_external_arf_indexes(&impl_ptr_->cpi->encode_command,
-                                          external_arf_indexes_.data());
+                                          GetVectorData(external_arf_indexes_));
   UpdateGroupOfPicture(impl_ptr_->cpi, frame_coding_index_, ref_frame_info_,
                        &group_of_picture_);
   rewind(in_file_);
@@ -952,7 +960,8 @@ int SimpleEncode::GetCodingFrameNum() const {
                              target_bitrate_, VPX_RC_LAST_PASS);
   FRAME_INFO frame_info = vp9_get_frame_info(&oxcf);
   FIRST_PASS_INFO first_pass_info;
-  fps_init_first_pass_info(&first_pass_info, impl_ptr_->first_pass_stats.data(),
+  fps_init_first_pass_info(&first_pass_info,
+                           GetVectorData(impl_ptr_->first_pass_stats),
                            num_frames_);
   return vp9_get_coding_frame_num(external_arf_indexes_.data(), &oxcf,
                                   &frame_info, &first_pass_info,