Re-enable PCAP reading in neteq_rtpplay

webrtc/modules/audio_coding/neteq/tools/rtp_file_source.cc

Index: webrtc/modules/audio_coding/neteq/tools/rtp_file_source.cc
diff --git a/webrtc/modules/audio_coding/neteq/tools/rtp_file_source.cc b/webrtc/modules/audio_coding/neteq/tools/rtp_file_source.cc
index 9681ad17ea827ed2477754b169c0d061ae0b8cc9..e3a829bd243a7e4d5f1e203ad5587e2c96cd424b 100644
--- a/webrtc/modules/audio_coding/neteq/tools/rtp_file_source.cc
+++ b/webrtc/modules/audio_coding/neteq/tools/rtp_file_source.cc
@@ -32,6 +32,18 @@ RtpFileSource* RtpFileSource::Create(const std::string& file_name) {
   return source;
 }
 
+bool RtpFileSource::ValidRtpDump(const std::string& file_name) {
+  rtc::scoped_ptr<RtpFileReader> temp_file(
+      RtpFileReader::Create(RtpFileReader::kRtpDump, file_name));
+  return !!temp_file;

[ivoc, 2015/11/02 15:27:09]

I have a hard time understanding the !!, is there some alternative that might be
easier to understand for mere mortals like myself? :-)

[hlundin-webrtc, 2015/11/02 15:41:21]

I blame kwiberg for recruiting me to the dark side. I'll let him be the arbiter.

[kwiberg-webrtc, 2015/11/02 19:24:59]

!x is true if x is false, false if x is true. So !!x is false if x is false,
true if x is true. Basically, it's a shorter way to write static_cast<bool>(x).

If you feel that it's too short, note that any even number of exclamation marks
will do.

[hlundin-webrtc, 2015/11/03 06:44:41]

Thanks for providing that invaluable truth table.

I feel that !!temp_file is more attractable than static_cast<bool>(temp_file).

+}
+
+bool RtpFileSource::ValidPcap(const std::string& file_name) {
+  rtc::scoped_ptr<RtpFileReader> temp_file(
+      RtpFileReader::Create(RtpFileReader::kPcap, file_name));
+  return !!temp_file;
+}
+
 RtpFileSource::~RtpFileSource() {
 }