parser_tests: Move cue validation to test_util.

And tidy it up a bit.

Change-Id: I68e7f16ad2aa922fdb064802e8986a6955364c32

testing/test_util.cc

@@ -15,6 +15,10 @@
 #include <string>
 
 #include "common/libwebm_util.h"
+#include "common/webmids.h"
+
+#include "mkvparser/mkvparser.h"
+#include "mkvparser/mkvreader.h"
 
 namespace test {
 
@@ -55,4 +59,91 @@ bool CompareFiles(const std::string& file1, const std::string& file2) {
   return std::feof(f1.get()) && std::feof(f2.get());
 }
 
+bool HasCuePoints(const mkvparser::Segment* segment,
+                  std::int64_t* cues_offset) {
+  if (!segment || !cues_offset) {
+    return false;
+  }
+  using mkvparser::SeekHead;
+  const SeekHead* const seek_head = segment->GetSeekHead();
+  if (!seek_head) {
+    return false;
+  }
+
+  std::int64_t offset = 0;
+  for (int i = 0; i < seek_head->GetCount(); ++i) {
+    const SeekHead::Entry* const entry = seek_head->GetEntry(i);
+    // TODO(tomfinegan): Cues ID is really 0x1C53BB6B, aka kMkvCues, but
+    // mkvparser reads IDs as EBML unsigned ints in some cases, yielding magic
+    // numbers like the following. Investigate fixing this behavior.
+    if (entry->id == 0xC53BB6B) {  // Cues ID as stored in Entry class.
+      offset = entry->pos;
+    }
+  }
+
+  if (offset == -1) {
+    // No Cues found.
+    return false;
+  }
+  *cues_offset = offset;
+  return true;
+}
+
+bool ValidateCues(mkvparser::Segment* segment, mkvparser::IMkvReader* reader) {
+  if (!segment) {
+    return false;
+  }
+
+  std::int64_t cues_offset = 0;
+  if (!HasCuePoints(segment, &cues_offset)) {
+    // No cues to validate, everything is OK.
+    return true;
+  }
+
+  // Parse Cues.
+  long long cues_pos = 0;  // NOLINT
+  long cues_len = 0;  // NOLINT
+  if (segment->ParseCues(cues_offset, cues_pos, cues_len)) {
+    return false;
+  }
+
+  // Get a pointer to the video track if it exists. Otherwise, we assume
+  // that Cues are based on the first track (which is true for all our test
+  // files).
+  const mkvparser::Tracks* const tracks = segment->GetTracks();
+  const mkvparser::Track* cues_track = tracks->GetTrackByIndex(0);
+  for (int i = 1; i < static_cast<int>(tracks->GetTracksCount()); ++i) {
+    const mkvparser::Track* const track = tracks->GetTrackByIndex(i);
+    if (track->GetType() == mkvparser::Track::kVideo) {
+      cues_track = track;
+      break;
+    }
+  }
+
+  // Iterate through Cues and verify if they are pointing to the correct
+  // Cluster position.
+  const mkvparser::Cues* const cues = segment->GetCues();
+  const mkvparser::CuePoint* cue_point = NULL;
+  while (cues->LoadCuePoint()) {
+    if (!cue_point) {
+      cue_point = cues->GetFirst();
+    } else {
+      cue_point = cues->GetNext(cue_point);
+    }
+    const mkvparser::CuePoint::TrackPosition* const track_position =
+        cue_point->Find(cues_track);
+    const long long cluster_pos = track_position->m_pos +  // NOLINT
+                                  segment->m_start;
+
+    // If a cluster does not begin at |cluster_pos|, then the file is
+    // incorrect.
+    long length;  // NOLINT
+    const std::int64_t id = mkvparser::ReadID(reader, cluster_pos, length);
+    if (id != libwebm::kMkvCluster) {
+      return false;
+    }
+  }
+  return true;
+}
+
 }  // namespace test