uhd: reworked time_spec_t to be more flexible: arithmetic, comparison operators...

Replaced nsecs with fractional seconds in units of seconds.
Replaced nsecs and secs members with public function members.
time_spec_t has a more diverse set of constructors and methods.
It can handle the cases where frac secs are greater than 1 second.

3 files changed, 44 insertions, 26 deletions

diff --git a/host/lib/transport/gen_vrt.py b/host/lib/transport/gen_vrt.py
index d1e553c41..8e0fce9ff 100755
--- a/host/lib/transport/gen_vrt.py
+++ b/host/lib/transport/gen_vrt.py
@@ -97,7 +97,7 @@ void vrt::pack_$(suffix)(
         #end if
         ########## Integer Time ##########
         #if $pred & $tsi_p
-            header_buff[$num_header_words] = $(XE_MACRO)(metadata.time_spec.secs);
+            header_buff[$num_header_words] = $(XE_MACRO)(boost::uint32_t(metadata.time_spec.get_full_secs()));
             #set $num_header_words += 1
             #set $flags |= (0x3 << 22);
         #end if
@@ -105,7 +105,7 @@ void vrt::pack_$(suffix)(
         #if $pred & $tsf_p
             header_buff[$num_header_words] = 0;
             #set $num_header_words += 1
-            header_buff[$num_header_words] = $(XE_MACRO)(metadata.time_spec.get_ticks(tick_rate));
+            header_buff[$num_header_words] = $(XE_MACRO)(boost::uint32_t(metadata.time_spec.get_tick_count(tick_rate)));
             #set $num_header_words += 1
             #set $flags |= (0x1 << 20);
         #end if
@@ -147,6 +147,7 @@ void vrt::unpack_$(suffix)(
 ){
     //clear the metadata
     metadata = rx_metadata_t();
+    boost::uint32_t secs = 0, ticks = 0;
 
     //extract vrt header
     boost::uint32_t vrt_hdr_word = $(XE_MACRO)(header_buff[0]);
@@ -185,18 +186,19 @@ void vrt::unpack_$(suffix)(
         ########## Integer Time ##########
         #if $pred & $tsi_p
             #set $has_time_spec = True
-            metadata.time_spec.secs = $(XE_MACRO)(header_buff[$num_header_words]);
+            secs = $(XE_MACRO)(header_buff[$num_header_words]);
             #set $num_header_words += 1
         #end if
         ########## Fractional Time ##########
         #if $pred & $tsf_p
             #set $has_time_spec = True
             #set $num_header_words += 1
-            metadata.time_spec.set_ticks($(XE_MACRO)(header_buff[$num_header_words]), tick_rate);
+            ticks = $(XE_MACRO)(header_buff[$num_header_words]);
             #set $num_header_words += 1
         #end if
         #if $has_time_spec
             metadata.has_time_spec = true;
+            metadata.time_spec = time_spec_t(secs, ticks, tick_rate);
         #end if
         ########## Trailer ##########
         #if $pred & $tlr_p
diff --git a/host/lib/types.cpp b/host/lib/types.cpp
index 78a3d22ce..6a9fcf5b5 100644
--- a/host/lib/types.cpp
+++ b/host/lib/types.cpp
@@ -120,47 +120,63 @@ tx_metadata_t::tx_metadata_t(void):
 /***********************************************************************
  * time spec
  **********************************************************************/
-static inline void time_spec_normalize(time_spec_t &time_spec){
-    time_spec.secs += boost::uint32_t(std::ceil(time_spec.nsecs/1e9));
-    time_spec.nsecs = std::fmod(time_spec.nsecs, 1e9);
+time_spec_t::time_spec_t(double secs):
+    _full_secs(0),
+    _frac_secs(secs)
+{
+    /* NOP */
 }
 
-time_spec_t::time_spec_t(boost::uint32_t secs, double nsecs):
-    secs(secs),
-    nsecs(nsecs)
+time_spec_t::time_spec_t(time_t full_secs, double frac_secs):
+    _full_secs(full_secs),
+    _frac_secs(frac_secs)
 {
     /* NOP */
 }
 
-time_spec_t::time_spec_t(boost::uint32_t secs, boost::uint32_t ticks, double tick_rate):
-    secs(secs),
-    nsecs(double(ticks)*1e9/tick_rate)
+time_spec_t::time_spec_t(time_t full_secs, size_t tick_count, double tick_rate):
+    _full_secs(full_secs),
+    _frac_secs(double(tick_count)/tick_rate)
 {
     /* NOP */
 }
 
-boost::uint32_t time_spec_t::get_ticks(double tick_rate) const{
-    return boost::math::iround(nsecs*tick_rate*1e-9);
+size_t time_spec_t::get_tick_count(double tick_rate) const{
+    return boost::math::iround(this->get_frac_secs()*tick_rate);
+}
+
+double time_spec_t::get_real_secs(void) const{
+    return this->_full_secs + this->_frac_secs;
 }
 
-void time_spec_t::set_ticks(boost::uint32_t ticks, double tick_rate){
-    nsecs = double(ticks)*1e9/tick_rate;
+time_t time_spec_t::get_full_secs(void) const{
+    return this->_full_secs + time_t(std::floor(this->_frac_secs));
+}
+
+double time_spec_t::get_frac_secs(void) const{
+    return std::fmod(this->_frac_secs, 1.0);
 }
 
 time_spec_t &time_spec_t::operator+=(const time_spec_t &rhs){
-    this->secs += rhs.secs;
-    this->nsecs += rhs.nsecs;
+    this->_full_secs += rhs.get_full_secs();
+    this->_frac_secs += rhs.get_frac_secs();
     return *this;
 }
 
 time_spec_t &time_spec_t::operator-=(const time_spec_t &rhs){
-    this->secs -= rhs.secs;
-    this->nsecs -= rhs.nsecs;
+    this->_full_secs -= rhs.get_full_secs();
+    this->_frac_secs -= rhs.get_frac_secs();
     return *this;
 }
 
 bool uhd::operator==(const time_spec_t &lhs, const time_spec_t &rhs){
-    return lhs.secs == rhs.secs and lhs.nsecs == rhs.nsecs;
+    return lhs.get_full_secs() == rhs.get_full_secs() and lhs.get_frac_secs() == rhs.get_frac_secs();
+}
+
+bool uhd::operator<(const time_spec_t &lhs, const time_spec_t &rhs){
+    if (lhs.get_full_secs() < rhs.get_full_secs()) return true;
+    if (lhs.get_full_secs() > rhs.get_full_secs()) return false;
+    return lhs.get_frac_secs() < rhs.get_frac_secs();
 }
 
 /***********************************************************************
diff --git a/host/lib/usrp/usrp2/mboard_impl.cpp b/host/lib/usrp/usrp2/mboard_impl.cpp
index 78fc5dc23..1a0f9916b 100644
--- a/host/lib/usrp/usrp2/mboard_impl.cpp
+++ b/host/lib/usrp/usrp2/mboard_impl.cpp
@@ -84,14 +84,14 @@ void usrp2_impl::update_clock_config(void){
 
 void usrp2_impl::set_time_spec(const time_spec_t &time_spec, bool now){
     //set the ticks
-    _iface->poke32(U2_REG_TIME64_TICKS, time_spec.get_ticks(get_master_clock_freq()));
+    _iface->poke32(U2_REG_TIME64_TICKS, time_spec.get_tick_count(get_master_clock_freq()));
 
     //set the flags register
     boost::uint32_t imm_flags = (now)? U2_FLAG_TIME64_LATCH_NOW : U2_FLAG_TIME64_LATCH_NEXT_PPS;
     _iface->poke32(U2_REG_TIME64_IMM, imm_flags);
 
     //set the seconds (latches in all 3 registers)
-    _iface->poke32(U2_REG_TIME64_SECS, time_spec.secs);
+    _iface->poke32(U2_REG_TIME64_SECS, time_spec.get_full_secs());
 }
 
 void usrp2_impl::issue_ddc_stream_cmd(const stream_cmd_t &stream_cmd){
@@ -118,8 +118,8 @@ void usrp2_impl::issue_ddc_stream_cmd(const stream_cmd_t &stream_cmd){
         (inst_chain)? 1 : 0,
         (inst_reload)? 1 : 0
     ));
-    _iface->poke32(U2_REG_RX_CTRL_TIME_SECS,  stream_cmd.time_spec.secs);
-    _iface->poke32(U2_REG_RX_CTRL_TIME_TICKS, stream_cmd.time_spec.get_ticks(get_master_clock_freq()));
+    _iface->poke32(U2_REG_RX_CTRL_TIME_SECS,  stream_cmd.time_spec.get_full_secs());
+    _iface->poke32(U2_REG_RX_CTRL_TIME_TICKS, stream_cmd.time_spec.get_tick_count(get_master_clock_freq()));
 }
 
 /***********************************************************************