Return AVERROR_EOF from the avio_read method when appropriate.

3 files changed, 19 insertions, 6 deletions

diff --git a/src/lib/ffmpeg.cc b/src/lib/ffmpeg.cc
index 6c8509b6c..8220962d6 100644
--- a/src/lib/ffmpeg.cc
+++ b/src/lib/ffmpeg.cc
@@ -273,7 +273,11 @@ FFmpeg::subtitle_codec_context () const
 int
 FFmpeg::avio_read (uint8_t* buffer, int const amount)
 {
-	return _file_group.read (buffer, amount);
+	auto result = _file_group.read(buffer, amount);
+	if (result.eof && result.bytes_read == 0) {
+		return AVERROR_EOF;
+	}
+	return result.bytes_read;
 }
 
 
diff --git a/src/lib/file_group.cc b/src/lib/file_group.cc
index 71faacc4c..f4d50028e 100644
--- a/src/lib/file_group.cc
+++ b/src/lib/file_group.cc
@@ -134,9 +134,8 @@ FileGroup::seek (int64_t pos, int whence) const
 /** Try to read some data from the current position into a buffer.
  *  @param buffer Buffer to write data into.
  *  @param amount Number of bytes to read.
- *  @return Number of bytes read.
  */
-int
+FileGroup::Result
 FileGroup::read (uint8_t* buffer, int amount) const
 {
 	DCPOMATIC_ASSERT (_current_file);
@@ -173,13 +172,13 @@ FileGroup::read (uint8_t* buffer, int amount) const
 		if (eof) {
 			/* See if there is another file to use */
 			if ((_current_path + 1) >= _paths.size()) {
-				break;
+				return { read, true };
 			}
 			ensure_open_path (_current_path + 1);
 		}
 	}
 
-	return read;
+	return { read, false };
 }
 
 
diff --git a/src/lib/file_group.h b/src/lib/file_group.h
index 693bf89ba..aac72c228 100644
--- a/src/lib/file_group.h
+++ b/src/lib/file_group.h
@@ -49,8 +49,18 @@ public:
 
 	void set_paths (std::vector<boost::filesystem::path> const &);
 
+	struct Result {
+		Result(int bytes_read_, bool eof_)
+			: bytes_read(bytes_read_)
+			, eof(eof_)
+		{}
+
+		int bytes_read = 0;
+		bool eof = false;
+	};
+
 	int64_t seek (int64_t, int) const;
-	int read (uint8_t*, int) const;
+	Result read (uint8_t*, int) const;
 	int64_t length () const;
 
 private: