1 files changed, 47 insertions, 0 deletions
diff --git a/src/base/data_range_tracking_destination.cc b/src/base/data_range_tracking_destination.cc
new file mode 100644
index 0000000..98e5b06
--- /dev/null
+++ b/src/base/data_range_tracking_destination.cc
@@ -0,0 +1,47 @@
+#include "image_io/base/data_range_tracking_destination.h"
+
+namespace photos_editing_formats {
+namespace image_io {
+
+void DataRangeTrackingDestination::StartTransfer() {
+  tracked_data_range_ = DataRange();
+  bytes_transferred_ = 0;
+  has_disjoint_transfer_ranges_ = false;
+  if (destination_ != nullptr) {
+    destination_->StartTransfer();
+  }
+}
+
+DataDestination::TransferStatus DataRangeTrackingDestination::Transfer(
+    const DataRange& transfer_range, const DataSegment& data_segment) {
+  DataDestination::TransferStatus transfer_status =
+      destination_ ? destination_->Transfer(transfer_range, data_segment)
+                   : DataDestination::kTransferOk;
+  if (transfer_status != kTransferError) {
+    bytes_transferred_ += transfer_range.GetLength();
+  }
+  if (has_disjoint_transfer_ranges_) {
+    return transfer_status;
+  }
+  if (!tracked_data_range_.IsValid()) {
+    tracked_data_range_ = transfer_range;
+    return transfer_status;
+  }
+  if (tracked_data_range_.GetEnd() == transfer_range.GetBegin()) {
+    tracked_data_range_ =
+        DataRange(tracked_data_range_.GetBegin(), transfer_range.GetEnd());
+    return transfer_status;
+  } else {
+    has_disjoint_transfer_ranges_ = true;
+    return transfer_status;
+  }
+}
+
+void DataRangeTrackingDestination::FinishTransfer() {
+  if (destination_ != nullptr) {
+    destination_->FinishTransfer();
+  }
+}
+
+}  // namespace image_io
+}  // namespace photos_editing_formats