Add a constructor that can read the next frame from a dcp::File.

2 files changed, 15 insertions, 0 deletions

diff --git a/src/lib/j2k_frame_info.cc b/src/lib/j2k_frame_info.cc
index 0e83c61f0..b260166ea 100644
--- a/src/lib/j2k_frame_info.cc
+++ b/src/lib/j2k_frame_info.cc
@@ -41,9 +41,22 @@ J2KFrameInfo::J2KFrameInfo(dcp::J2KFrameInfo const& info)
 }
 
 
+J2KFrameInfo::J2KFrameInfo(dcp::File& info_file)
+{
+	read(info_file);
+}
+
+
 J2KFrameInfo::J2KFrameInfo(dcp::File& info_file, Frame frame, Eyes eyes)
 {
 	info_file.seek(position(frame, eyes), SEEK_SET);
+	read(info_file);
+}
+
+
+void
+J2KFrameInfo::read(dcp::File& info_file)
+{
 	info_file.checked_read(&offset, sizeof(offset));
 	info_file.checked_read(&size, sizeof(size));
 
diff --git a/src/lib/j2k_frame_info.h b/src/lib/j2k_frame_info.h
index da9503248..d1ffd4d7c 100644
--- a/src/lib/j2k_frame_info.h
+++ b/src/lib/j2k_frame_info.h
@@ -29,6 +29,7 @@ class J2KFrameInfo : public dcp::J2KFrameInfo
 public:
 	J2KFrameInfo(dcp::J2KFrameInfo const& info);
 	J2KFrameInfo(uint64_t offset_, uint64_t size_, std::string hash_);
+	J2KFrameInfo(dcp::File& info_file);
 	/** Seek to the required position in info_file and read the info for
 	 *  the given frame and eyes.
 	 */
@@ -45,6 +46,7 @@ public:
 
 private:
 	long position(Frame frame, Eyes eyes) const;
+	void read(dcp::File& info_file);
 
 	static constexpr auto _size_on_disk = 32 + sizeof(dcp::J2KFrameInfo::offset) + sizeof(dcp::J2KFrameInfo::size);
 };