From 2d5498200953b45e3774ae8dd2d5df574062e8d4 Mon Sep 17 00:00:00 2001
From: kevin <kevin@larke.org>
Date: Mon, 11 Oct 2021 12:22:27 -0400
Subject: [PATCH] cwTime.h,cpp : Added seconds,milli,microToSpec() and
 subtractMicros()

---
 cwTime.cpp | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 cwTime.h   |  6 +++++
 2 files changed, 70 insertions(+)

diff --git a/cwTime.cpp b/cwTime.cpp
index 81a5dcb..b18b15f 100644
--- a/cwTime.cpp
+++ b/cwTime.cpp
@@ -142,6 +142,35 @@ cw::rc_t cw::time::now( spec_t& ts )
   return rc;
 }
 
+void cw::time::subtractMicros( spec_t& ts, unsigned micros )
+{
+  
+  unsigned rem_us = micros % 1000000;  // fractional seconds in microseconds
+  unsigned rem_ns = rem_us * 1000;     // fractional seconds in nanoseconds
+
+  // if the fractional micros is greater than the fractional nano's
+  if( rem_ns > ts.tv_nsec )
+  {
+    // subtract the fractional nano's from the fractional micros
+    // (this sets the fractional nano's to 0)
+    rem_ns    -= ts.tv_nsec;
+    
+    // convert the remaining fractional micros to the fractional nano's
+    ts.tv_nsec = 1000000000 - rem_ns;
+    
+    // subtract the carry
+    ts.tv_sec -= 1;
+  }
+  else 
+  {
+    ts.tv_nsec -= rem_ns;
+  }
+
+  assert( ts.tv_sec > micros / 1000000 );
+  
+  ts.tv_sec -= micros / 1000000;
+  
+}
 
 void cw::time::advanceMs( spec_t& ts, unsigned ms )
 {
@@ -171,6 +200,29 @@ cw::rc_t cw::time::futureMs( spec_t& ts, unsigned ms )
   return rc;   
 }
 
+void cw::time::secondsToSpec(      spec_t& ts, unsigned sec )
+{
+  ts.tv_sec  = sec;
+  ts.tv_nsec = 0;  
+}
+
+void cw::time::millisecondsToSpec( spec_t& ts, unsigned ms )
+{
+  unsigned sec = ms/1000;
+  unsigned ns  = (ms - (sec*1000)) * 1000000;
+  
+  ts.tv_sec  = sec;
+  ts.tv_nsec = ns;  
+}
+
+void cw::time::microsecondsToSpec( spec_t& ts, unsigned us )
+{
+  unsigned sec = us/1000000;
+  unsigned ns  = (us - (sec*1000000)) * 1000;
+  
+  ts.tv_sec  = sec;
+  ts.tv_nsec = ns;  
+}
 
 cw::rc_t cw::time::test()
 {
@@ -185,6 +237,18 @@ cw::rc_t cw::time::test()
 
   printf("dMs:%i : GTE:%i LTE:%i\n",dMs, isGTE(t0,t1), isLTE(t0,t1) );
 
+  
+  microsecondsToSpec( t0, 2500000 );        // 2.5 seconds
+  printf("%li %li\n",t0.tv_sec,t0.tv_nsec);
+  subtractMicros( t0, 750000 );             // subtract .75 seconds
+  printf("%li %li\n",t0.tv_sec,t0.tv_nsec);
+  subtractMicros( t0, 500000 );             // subtract .5 seconds
+  printf("%li %li\n",t0.tv_sec,t0.tv_nsec);
+
+  
+
   return kOkRC;
   
 }
+
+
diff --git a/cwTime.h b/cwTime.h
index 34c485f..f9a22e6 100644
--- a/cwTime.h
+++ b/cwTime.h
@@ -53,12 +53,18 @@ namespace cw
 
     rc_t now( spec_t& ts );
 
+    void subtractMicros( spec_t& ts, unsigned us );
+    
     // Advance 'ts' by 'ms' milliseconds.
     void advanceMs( spec_t& ts, unsigned ms );
 
     // Advance the current time by 'ms' milliseconds;
     rc_t futureMs( spec_t& ts, unsigned ms );
 
+    void secondsToSpec(      spec_t& ts, unsigned sec );
+    void millisecondsToSpec( spec_t& ts, unsigned ms );
+    void microsecondsToSpec( spec_t& ts, unsigned us );
+
     rc_t test();
 
     //)