Revert "Use make_shared<>."
[dcpomatic.git] / src / lib / player.cc
index ca833208cee034b6113f904ed997f73e43aaa882..30313d39dd23bb57445cf43ff8a45f7b9c2d8b00 100644 (file)
@@ -1,34 +1,27 @@
 /*
-    Copyright (C) 2013-2015 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2013-2016 Carl Hetherington <cth@carlh.net>
 
-    This program is free software; you can redistribute it and/or modify
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.
 
-    This program is distributed in the hope that it will be useful,
+    DCP-o-matic is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
 
 */
 
 #include "player.h"
 #include "film.h"
-#include "ffmpeg_decoder.h"
 #include "audio_buffers.h"
-#include "ffmpeg_content.h"
-#include "image_decoder.h"
-#include "image_content.h"
-#include "sndfile_decoder.h"
-#include "sndfile_content.h"
-#include "subtitle_content.h"
-#include "text_subtitle_decoder.h"
-#include "text_subtitle_content.h"
+#include "content_audio.h"
 #include "dcp_content.h"
 #include "job.h"
 #include "image.h"
 #include "content_video.h"
 #include "player_video.h"
 #include "frame_rate_change.h"
-#include "dcp_content.h"
-#include "dcp_decoder.h"
-#include "dcp_subtitle_content.h"
-#include "dcp_subtitle_decoder.h"
 #include "audio_processor.h"
 #include "playlist.h"
 #include "referenced_reel_asset.h"
+#include "decoder_factory.h"
+#include "decoder.h"
+#include "video_decoder.h"
+#include "audio_decoder.h"
+#include "subtitle_content.h"
+#include "subtitle_decoder.h"
+#include "ffmpeg_content.h"
+#include "audio_content.h"
+#include "content_subtitle.h"
+#include "dcp_decoder.h"
+#include "image_decoder.h"
 #include <dcp/reel.h>
 #include <dcp/reel_sound_asset.h>
 #include <dcp/reel_subtitle_asset.h>
@@ -76,6 +76,24 @@ using boost::dynamic_pointer_cast;
 using boost::optional;
 using boost::scoped_ptr;
 
+static bool
+has_video (Content* c)
+{
+       return static_cast<bool>(c->video);
+}
+
+static bool
+has_audio (Content* c)
+{
+       return static_cast<bool>(c->audio);
+}
+
+static bool
+has_subtitle (Content* c)
+{
+       return static_cast<bool>(c->subtitle);
+}
+
 Player::Player (shared_ptr<const Film> film, shared_ptr<const Playlist> playlist)
        : _film (film)
        , _playlist (playlist)
@@ -97,7 +115,6 @@ Player::Player (shared_ptr<const Film> film, shared_ptr<const Playlist> playlist
 void
 Player::setup_pieces ()
 {
-       list<shared_ptr<Piece> > old_pieces = _pieces;
        _pieces.clear ();
 
        BOOST_FOREACH (shared_ptr<Content> i, _playlist->content ()) {
@@ -106,98 +123,23 @@ Player::setup_pieces ()
                        continue;
                }
 
-               shared_ptr<Decoder> decoder;
-               optional<FrameRateChange> frc;
-
-               /* FFmpeg */
-               shared_ptr<const FFmpegContent> fc = dynamic_pointer_cast<const FFmpegContent> (i);
-               if (fc) {
-                       decoder.reset (new FFmpegDecoder (fc, _film->log(), _fast));
-                       frc = FrameRateChange (fc->video->video_frame_rate(), _film->video_frame_rate());
-               }
-
-               shared_ptr<const DCPContent> dc = dynamic_pointer_cast<const DCPContent> (i);
-               if (dc) {
-                       decoder.reset (new DCPDecoder (dc, _film->log(), _fast));
-                       frc = FrameRateChange (dc->video->video_frame_rate(), _film->video_frame_rate());
-               }
-
-               /* ImageContent */
-               shared_ptr<const ImageContent> ic = dynamic_pointer_cast<const ImageContent> (i);
-               if (ic) {
-                       /* See if we can re-use an old ImageDecoder */
-                       for (list<shared_ptr<Piece> >::const_iterator j = old_pieces.begin(); j != old_pieces.end(); ++j) {
-                               shared_ptr<ImageDecoder> imd = dynamic_pointer_cast<ImageDecoder> ((*j)->decoder);
-                               if (imd && imd->content() == ic) {
-                                       decoder = imd;
-                               }
-                       }
-
-                       if (!decoder) {
-                               decoder.reset (new ImageDecoder (ic, _film->log()));
-                       }
-
-                       frc = FrameRateChange (ic->video->video_frame_rate(), _film->video_frame_rate());
-               }
-
-               /* SndfileContent */
-               shared_ptr<const SndfileContent> sc = dynamic_pointer_cast<const SndfileContent> (i);
-               if (sc) {
-                       decoder.reset (new SndfileDecoder (sc, _fast));
-
-                       /* Work out a FrameRateChange for the best overlap video for this content */
-                       DCPTime best_overlap_t;
-                       shared_ptr<Content> best_overlap;
-                       BOOST_FOREACH (shared_ptr<Content> j, _playlist->content ()) {
-                               if (!j->video) {
-                                       continue;
-                               }
-
-                               DCPTime const overlap = min (j->end(), i->end()) - max (j->position(), i->position());
-                               if (overlap > best_overlap_t) {
-                                       best_overlap = j;
-                                       best_overlap_t = overlap;
-                               }
-                       }
-
-                       if (best_overlap) {
-                               frc = FrameRateChange (best_overlap->video->video_frame_rate(), _film->video_frame_rate ());
-                       } else {
-                               /* No video overlap; e.g. if the DCP is just audio */
-                               frc = FrameRateChange (_film->video_frame_rate(), _film->video_frame_rate ());
-                       }
-               }
-
-               /* It's questionable whether subtitle content should have a video frame rate; perhaps
-                  it should be assumed that any subtitle content has been prepared at the same rate
-                  as simultaneous video content (like we do with audio).
-               */
+               shared_ptr<Decoder> decoder = decoder_factory (i, _film->log(), _fast);
+               FrameRateChange frc (i->active_video_frame_rate(), _film->video_frame_rate());
 
-               /* TextSubtitleContent */
-               shared_ptr<const TextSubtitleContent> rc = dynamic_pointer_cast<const TextSubtitleContent> (i);
-               if (rc) {
-                       decoder.reset (new TextSubtitleDecoder (rc));
-                       frc = FrameRateChange (rc->subtitle_video_frame_rate(), _film->video_frame_rate());
-               }
-
-               /* DCPSubtitleContent */
-               shared_ptr<const DCPSubtitleContent> dsc = dynamic_pointer_cast<const DCPSubtitleContent> (i);
-               if (dsc) {
-                       decoder.reset (new DCPSubtitleDecoder (dsc));
-                       frc = FrameRateChange (dsc->subtitle_video_frame_rate(), _film->video_frame_rate());
+               if (!decoder) {
+                       /* Not something that we can decode; e.g. Atmos content */
+                       continue;
                }
 
-               shared_ptr<VideoDecoder> vd = dynamic_pointer_cast<VideoDecoder> (decoder);
-               if (vd && _ignore_video) {
-                       vd->set_ignore_video ();
+               if (decoder->video && _ignore_video) {
+                       decoder->video->set_ignore ();
                }
 
-               shared_ptr<AudioDecoder> ad = dynamic_pointer_cast<AudioDecoder> (decoder);
-               if (ad && _ignore_audio) {
-                       ad->set_ignore_audio ();
+               if (decoder->audio && _ignore_audio) {
+                       decoder->audio->set_ignore ();
                }
 
-               _pieces.push_back (shared_ptr<Piece> (new Piece (i, decoder, frc.get ())));
+               _pieces.push_back (shared_ptr<Piece> (new Piece (i, decoder, frc)));
        }
 
        _have_valid_pieces = true;
@@ -217,11 +159,11 @@ Player::playlist_content_changed (weak_ptr<Content> w, int property, bool freque
                property == ContentProperty::TRIM_START ||
                property == ContentProperty::TRIM_END ||
                property == ContentProperty::PATH ||
-               property == VideoContentProperty::VIDEO_FRAME_TYPE ||
+               property == VideoContentProperty::FRAME_TYPE ||
                property == DCPContentProperty::CAN_BE_PLAYED ||
-               property == TextSubtitleContentProperty::TEXT_SUBTITLE_COLOUR ||
-               property == TextSubtitleContentProperty::TEXT_SUBTITLE_OUTLINE ||
-               property == TextSubtitleContentProperty::TEXT_SUBTITLE_OUTLINE_COLOUR ||
+               property == SubtitleContentProperty::COLOUR ||
+               property == SubtitleContentProperty::OUTLINE ||
+               property == SubtitleContentProperty::OUTLINE_COLOUR ||
                property == FFmpegContentProperty::SUBTITLE_STREAM
                ) {
 
@@ -229,17 +171,17 @@ Player::playlist_content_changed (weak_ptr<Content> w, int property, bool freque
                Changed (frequent);
 
        } else if (
-               property == SubtitleContentProperty::USE_SUBTITLES ||
-               property == SubtitleContentProperty::SUBTITLE_X_OFFSET ||
-               property == SubtitleContentProperty::SUBTITLE_Y_OFFSET ||
-               property == SubtitleContentProperty::SUBTITLE_X_SCALE ||
-               property == SubtitleContentProperty::SUBTITLE_Y_SCALE ||
+               property == ContentProperty::VIDEO_FRAME_RATE ||
+               property == SubtitleContentProperty::USE ||
+               property == SubtitleContentProperty::X_OFFSET ||
+               property == SubtitleContentProperty::Y_OFFSET ||
+               property == SubtitleContentProperty::X_SCALE ||
+               property == SubtitleContentProperty::Y_SCALE ||
                property == SubtitleContentProperty::FONTS ||
-               property == VideoContentProperty::VIDEO_CROP ||
-               property == VideoContentProperty::VIDEO_SCALE ||
-               property == VideoContentProperty::VIDEO_FRAME_RATE ||
-               property == VideoContentProperty::VIDEO_FADE_IN ||
-               property == VideoContentProperty::VIDEO_FADE_OUT ||
+               property == VideoContentProperty::CROP ||
+               property == VideoContentProperty::SCALE ||
+               property == VideoContentProperty::FADE_IN ||
+               property == VideoContentProperty::FADE_OUT ||
                property == VideoContentProperty::COLOUR_CONVERSION
                ) {
 
@@ -383,9 +325,10 @@ Player::get_video (DCPTime time, bool accurate)
 
        /* Find pieces containing video which is happening now */
 
-       list<shared_ptr<Piece> > ov = overlaps<VideoContent> (
+       list<shared_ptr<Piece> > ov = overlaps (
                time,
-               time + DCPTime::from_frames (1, _film->video_frame_rate ())
+               time + DCPTime::from_frames (1, _film->video_frame_rate ()),
+               &has_video
                );
 
        list<shared_ptr<PlayerVideo> > pvf;
@@ -396,12 +339,12 @@ Player::get_video (DCPTime time, bool accurate)
        } else {
                /* Some video content at this time */
                shared_ptr<Piece> last = *(ov.rbegin ());
-               VideoFrameType const last_type = last->content->video->video_frame_type ();
+               VideoFrameType const last_type = last->content->video->frame_type ();
 
                /* Get video from appropriate piece(s) */
                BOOST_FOREACH (shared_ptr<Piece> piece, ov) {
 
-                       shared_ptr<VideoDecoder> decoder = dynamic_pointer_cast<VideoDecoder> (piece->decoder);
+                       shared_ptr<VideoDecoder> decoder = piece->decoder->video;
                        DCPOMATIC_ASSERT (decoder);
 
                        shared_ptr<DCPContent> dcp_content = dynamic_pointer_cast<DCPContent> (piece->content);
@@ -413,12 +356,12 @@ Player::get_video (DCPTime time, bool accurate)
                                /* always use the last video */
                                piece == last ||
                                /* with a corresponding L/R eye if appropriate */
-                               (last_type == VIDEO_FRAME_TYPE_3D_LEFT && piece->content->video->video_frame_type() == VIDEO_FRAME_TYPE_3D_RIGHT) ||
-                               (last_type == VIDEO_FRAME_TYPE_3D_RIGHT && piece->content->video->video_frame_type() == VIDEO_FRAME_TYPE_3D_LEFT);
+                               (last_type == VIDEO_FRAME_TYPE_3D_LEFT && piece->content->video->frame_type() == VIDEO_FRAME_TYPE_3D_RIGHT) ||
+                               (last_type == VIDEO_FRAME_TYPE_3D_RIGHT && piece->content->video->frame_type() == VIDEO_FRAME_TYPE_3D_LEFT);
 
                        if (use) {
                                /* We want to use this piece */
-                               list<ContentVideo> content_video = decoder->get_video (dcp_to_content_video (piece, time), accurate);
+                               list<ContentVideo> content_video = decoder->get (dcp_to_content_video (piece, time), accurate);
                                if (content_video.empty ()) {
                                        pvf.push_back (black_player_video_frame (time));
                                } else {
@@ -431,12 +374,12 @@ Player::get_video (DCPTime time, bool accurate)
                                                        shared_ptr<PlayerVideo> (
                                                                new PlayerVideo (
                                                                        i->image,
-                                                                       content_video_to_dcp (piece, i->frame),
+                                                                       time,
                                                                        piece->content->video->crop (),
-                                                                       piece->content->video->fade (i->frame),
+                                                                       piece->content->video->fade (i->frame.index()),
                                                                        image_size,
                                                                        _video_container_size,
-                                                                       i->eyes,
+                                                                       i->frame.eyes(),
                                                                        i->part,
                                                                        piece->content->video->colour_conversion ()
                                                                        )
@@ -446,7 +389,7 @@ Player::get_video (DCPTime time, bool accurate)
                                }
                        } else {
                                /* Discard unused video */
-                               decoder->get_video (dcp_to_content_video (piece, time), accurate);
+                               decoder->get (dcp_to_content_video (piece, time), accurate);
                        }
                }
        }
@@ -473,16 +416,15 @@ Player::get_audio (DCPTime time, DCPTime length, bool accurate)
        shared_ptr<AudioBuffers> audio (new AudioBuffers (_film->audio_channels(), length_frames));
        audio->make_silent ();
 
-       list<shared_ptr<Piece> > ov = overlaps<AudioContent> (time, time + length);
+       list<shared_ptr<Piece> > ov = overlaps (time, time + length, has_audio);
        if (ov.empty ()) {
                return audio;
        }
 
        bool all_referenced = true;
        BOOST_FOREACH (shared_ptr<Piece> i, ov) {
-               shared_ptr<AudioContent> audio_content = dynamic_pointer_cast<AudioContent> (i->content);
                shared_ptr<DCPContent> dcp_content = dynamic_pointer_cast<DCPContent> (i->content);
-               if (audio_content && (!dcp_content || !dcp_content->reference_audio ())) {
+               if (i->content->audio && (!dcp_content || !dcp_content->reference_audio ())) {
                        /* There is audio content which is not from a DCP or not set to be referenced */
                        all_referenced = false;
                }
@@ -494,13 +436,12 @@ Player::get_audio (DCPTime time, DCPTime length, bool accurate)
 
        BOOST_FOREACH (shared_ptr<Piece> i, ov) {
 
-               shared_ptr<AudioContent> content = dynamic_pointer_cast<AudioContent> (i->content);
-               DCPOMATIC_ASSERT (content);
-               shared_ptr<AudioDecoder> decoder = dynamic_pointer_cast<AudioDecoder> (i->decoder);
+               DCPOMATIC_ASSERT (i->content->audio);
+               shared_ptr<AudioDecoder> decoder = i->decoder->audio;
                DCPOMATIC_ASSERT (decoder);
 
                /* The time that we should request from the content */
-               DCPTime request = time - DCPTime::from_seconds (content->audio_delay() / 1000.0);
+               DCPTime request = time - DCPTime::from_seconds (i->content->audio->delay() / 1000.0);
                Frame request_frames = length_frames;
                DCPTime offset;
                if (request < DCPTime ()) {
@@ -517,7 +458,7 @@ Player::get_audio (DCPTime time, DCPTime length, bool accurate)
 
                Frame const content_frame = dcp_to_resampled_audio (i, request);
 
-               BOOST_FOREACH (AudioStreamPtr j, content->audio_streams ()) {
+               BOOST_FOREACH (AudioStreamPtr j, i->content->audio->streams ()) {
 
                        if (j->channels() == 0) {
                                /* Some content (e.g. DCPs) can have streams with no channels */
@@ -525,12 +466,12 @@ Player::get_audio (DCPTime time, DCPTime length, bool accurate)
                        }
 
                        /* Audio from this piece's decoder stream (which might be more or less than what we asked for) */
-                       ContentAudio all = decoder->get_audio (j, content_frame, request_frames, accurate);
+                       ContentAudio all = decoder->get (j, content_frame, request_frames, accurate);
 
                        /* Gain */
-                       if (content->audio_gain() != 0) {
+                       if (i->content->audio->gain() != 0) {
                                shared_ptr<AudioBuffers> gain (new AudioBuffers (all.audio));
-                               gain->apply_gain (content->audio_gain ());
+                               gain->apply_gain (i->content->audio->gain ());
                                all.audio = gain;
                        }
 
@@ -572,7 +513,6 @@ Player::get_audio (DCPTime time, DCPTime length, bool accurate)
 Frame
 Player::dcp_to_content_video (shared_ptr<const Piece> piece, DCPTime t) const
 {
-       shared_ptr<const VideoContent> vc = dynamic_pointer_cast<const VideoContent> (piece->content);
        DCPTime s = t - piece->content->position ();
        s = min (piece->content->length_after_trim(), s);
        s = max (DCPTime(), s + DCPTime (piece->content->trim_start(), piece->frc));
@@ -590,7 +530,6 @@ Player::dcp_to_content_video (shared_ptr<const Piece> piece, DCPTime t) const
 DCPTime
 Player::content_video_to_dcp (shared_ptr<const Piece> piece, Frame f) const
 {
-       shared_ptr<const VideoContent> vc = dynamic_pointer_cast<const VideoContent> (piece->content);
        /* See comment in dcp_to_content_video */
        DCPTime const d = DCPTime::from_frames (f * piece->frc.factor(), piece->frc.dcp) - DCPTime (piece->content->trim_start (), piece->frc);
        return max (DCPTime (), d + piece->content->position ());
@@ -626,12 +565,12 @@ Player::content_subtitle_to_dcp (shared_ptr<const Piece> piece, ContentTime t) c
 PlayerSubtitles
 Player::get_subtitles (DCPTime time, DCPTime length, bool starting, bool burnt, bool accurate)
 {
-       list<shared_ptr<Piece> > subs = overlaps<SubtitleContent> (time, time + length);
+       list<shared_ptr<Piece> > subs = overlaps (time, time + length, has_subtitle);
 
        PlayerSubtitles ps (time, length);
 
        for (list<shared_ptr<Piece> >::const_iterator j = subs.begin(); j != subs.end(); ++j) {
-               if (!(*j)->content->subtitle->use_subtitles () || (!_always_burn_subtitles && (burnt != (*j)->content->subtitle->burn_subtitles ()))) {
+               if (!(*j)->content->subtitle->use () || (!_always_burn_subtitles && (burnt != (*j)->content->subtitle->burn ()))) {
                        continue;
                }
 
@@ -640,36 +579,36 @@ Player::get_subtitles (DCPTime time, DCPTime length, bool starting, bool burnt,
                        continue;
                }
 
-               shared_ptr<SubtitleDecoder> subtitle_decoder = dynamic_pointer_cast<SubtitleDecoder> ((*j)->decoder);
+               shared_ptr<SubtitleDecoder> subtitle_decoder = (*j)->decoder->subtitle;
                ContentTime const from = dcp_to_content_subtitle (*j, time);
                /* XXX: this video_frame_rate() should be the rate that the subtitle content has been prepared for */
                ContentTime const to = from + ContentTime::from_frames (1, _film->video_frame_rate ());
 
-               list<ContentImageSubtitle> image = subtitle_decoder->get_image_subtitles (ContentTimePeriod (from, to), starting, accurate);
+               list<ContentImageSubtitle> image = subtitle_decoder->get_image (ContentTimePeriod (from, to), starting, accurate);
                for (list<ContentImageSubtitle>::iterator i = image.begin(); i != image.end(); ++i) {
 
                        /* Apply content's subtitle offsets */
-                       i->sub.rectangle.x += (*j)->content->subtitle->subtitle_x_offset ();
-                       i->sub.rectangle.y += (*j)->content->subtitle->subtitle_y_offset ();
+                       i->sub.rectangle.x += (*j)->content->subtitle->x_offset ();
+                       i->sub.rectangle.y += (*j)->content->subtitle->y_offset ();
 
                        /* Apply content's subtitle scale */
-                       i->sub.rectangle.width *= (*j)->content->subtitle->subtitle_x_scale ();
-                       i->sub.rectangle.height *= (*j)->content->subtitle->subtitle_y_scale ();
+                       i->sub.rectangle.width *= (*j)->content->subtitle->x_scale ();
+                       i->sub.rectangle.height *= (*j)->content->subtitle->y_scale ();
 
                        /* Apply a corrective translation to keep the subtitle centred after that scale */
-                       i->sub.rectangle.x -= i->sub.rectangle.width * ((*j)->content->subtitle->subtitle_x_scale() - 1);
-                       i->sub.rectangle.y -= i->sub.rectangle.height * ((*j)->content->subtitle->subtitle_y_scale() - 1);
+                       i->sub.rectangle.x -= i->sub.rectangle.width * ((*j)->content->subtitle->x_scale() - 1);
+                       i->sub.rectangle.y -= i->sub.rectangle.height * ((*j)->content->subtitle->y_scale() - 1);
 
                        ps.image.push_back (i->sub);
                }
 
-               list<ContentTextSubtitle> text = subtitle_decoder->get_text_subtitles (ContentTimePeriod (from, to), starting, accurate);
+               list<ContentTextSubtitle> text = subtitle_decoder->get_text (ContentTimePeriod (from, to), starting, accurate);
                BOOST_FOREACH (ContentTextSubtitle& ts, text) {
                        BOOST_FOREACH (dcp::SubtitleString s, ts.subs) {
-                               s.set_h_position (s.h_position() + (*j)->content->subtitle->subtitle_x_offset ());
-                               s.set_v_position (s.v_position() + (*j)->content->subtitle->subtitle_y_offset ());
-                               float const xs = (*j)->content->subtitle->subtitle_x_scale();
-                               float const ys = (*j)->content->subtitle->subtitle_y_scale();
+                               s.set_h_position (s.h_position() + (*j)->content->subtitle->x_offset ());
+                               s.set_v_position (s.v_position() + (*j)->content->subtitle->y_offset ());
+                               float const xs = (*j)->content->subtitle->x_scale();
+                               float const ys = (*j)->content->subtitle->y_scale();
                                float size = s.size();
 
                                /* Adjust size to express the common part of the scaling;
@@ -704,12 +643,11 @@ Player::get_subtitle_fonts ()
 
        list<shared_ptr<Font> > fonts;
        BOOST_FOREACH (shared_ptr<Piece>& p, _pieces) {
-               shared_ptr<SubtitleContent> sc = dynamic_pointer_cast<SubtitleContent> (p->content);
-               if (sc) {
+               if (p->content->subtitle) {
                        /* XXX: things may go wrong if there are duplicate font IDs
                           with different font files.
                        */
-                       list<shared_ptr<Font> > f = sc->fonts ();
+                       list<shared_ptr<Font> > f = p->content->subtitle->fonts ();
                        copy (f.begin(), f.end(), back_inserter (fonts));
                }
        }
@@ -811,3 +749,20 @@ Player::get_reel_assets ()
 
        return a;
 }
+
+list<shared_ptr<Piece> >
+Player::overlaps (DCPTime from, DCPTime to, boost::function<bool (Content *)> valid)
+{
+       if (!_have_valid_pieces) {
+               setup_pieces ();
+       }
+
+       list<shared_ptr<Piece> > overlaps;
+       BOOST_FOREACH (shared_ptr<Piece> i, _pieces) {
+               if (valid (i->content.get ()) && i->content->position() < to && i->content->end() > from) {
+                       overlaps.push_back (i);
+               }
+       }
+
+       return overlaps;
+}