From 204d63929dab32961364fc876d347611ff79db77 Mon Sep 17 00:00:00 2001
From: Bill Somerville <bill@classdesign.com>
Date: Tue, 29 Sep 2020 12:32:47 +0100
Subject: [PATCH] Repair a regression with odd/2nd period FT4 decode timestamps

Generalized slow mode decode timestamp generation to a common routine.
---
 widgets/mainwindow.cpp | 31 ++++++++-----------------------
 widgets/mainwindow.h   |  1 -
 2 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 682fb9ad1..7262f2e12 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -3019,34 +3019,19 @@ void MainWindow::decode()                                       //decode()
   if( m_diskData ) {
     dec_data.params.lapcqonly=false;
   }
-  m_msec0=QDateTime::currentMSecsSinceEpoch();
   if(!m_dataAvailable or m_TRperiod==0.0) return;
   ui->DecodeButton->setChecked (true);
-  if(!dec_data.params.nagain && m_diskData && (m_TRperiod >= 60.0)) {
+  if(!dec_data.params.nagain && m_diskData && m_TRperiod >= 60.) {
     dec_data.params.nutc=dec_data.params.nutc/100;
   }
   if(dec_data.params.nagain==0 && dec_data.params.newdat==1 && (!m_diskData)) {
-    qint64 nperiods=now.toMSecsSinceEpoch()/(1000.0*m_TRperiod);
-    m_dateTimeSeqStart=QDateTime::fromMSecsSinceEpoch(qint64(1000.0*nperiods*m_TRperiod)).toUTC();
-    qint64 ms = QDateTime::currentMSecsSinceEpoch() % 86400000;
-    int imin=ms/60000;
-    int ihr=imin/60;
-    imin=imin % 60;
-    if(m_TRperiod>=60) imin=imin - (imin % (int(m_TRperiod)/60));
-    dec_data.params.nutc=100*ihr + imin;
-    if(m_TRperiod < 60) {
-      qint64 ms=1000.0*(2.0-m_TRperiod);
-      if(m_mode=="FST4") ms=1000.0*(6.0-m_TRperiod);
-      //Adjust for FT8 early decode:
-      if(m_mode=="FT8" and m_ihsym==m_earlyDecode and !m_diskData) ms+=(m_hsymStop-m_earlyDecode)*288;
-      if(m_mode=="FT8" and m_ihsym==m_earlyDecode2 and !m_diskData) ms+=(m_hsymStop-m_earlyDecode2)*288;
-      QDateTime t=QDateTime::currentDateTimeUtc().addMSecs(ms);
-      ihr=t.toString("hh").toInt();
-      imin=t.toString("mm").toInt();
-      int isec=t.toString("ss").toInt();
-      isec=isec - fmod(double(isec),m_TRperiod);
-      dec_data.params.nutc=10000*ihr + 100*imin + isec;
-    }
+    auto t_start = qt_truncate_date_time_to (QDateTime::currentDateTimeUtc (), m_TRperiod * 1.e3);
+    auto t = t_start.time ();
+    dec_data.params.nutc = t.hour () * 100 + t.minute ();
+    if (m_TRperiod < 60.)
+      {
+        dec_data.params.nutc = dec_data.params.nutc * 100 + t.second ();
+      }
   }
 
   if(m_nPick==1 and !m_diskData) {
diff --git a/widgets/mainwindow.h b/widgets/mainwindow.h
index 071ffd90d..8c19c8302 100644
--- a/widgets/mainwindow.h
+++ b/widgets/mainwindow.h
@@ -401,7 +401,6 @@ private:
   qint64  m_msErase;
   qint64  m_secBandChanged;
   qint64  m_freqMoon;
-  qint64  m_msec0;
   qint64  m_fullFoxCallTime;
 
   Frequency m_freqNominal;