usrp: Added fe_connection type and unit test

- Wraps a sampling mode and IF frequency
- Built-in parser to deduce swap,invert,mode bits from string connection

2 files changed, 68 insertions, 0 deletions

diff --git a/host/lib/usrp/CMakeLists.txt b/host/lib/usrp/CMakeLists.txt
index 71e40395e..dde4f02c3 100644
--- a/host/lib/usrp/CMakeLists.txt
+++ b/host/lib/usrp/CMakeLists.txt
@@ -29,6 +29,7 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_CURRENT_SOURCE_DIR}/mboard_eeprom.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/multi_usrp.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/subdev_spec.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/fe_connection.cpp
 )
 
 IF(ENABLE_C_API)
diff --git a/host/lib/usrp/fe_connection.cpp b/host/lib/usrp/fe_connection.cpp
new file mode 100644
index 000000000..071f5ecf2
--- /dev/null
+++ b/host/lib/usrp/fe_connection.cpp
@@ -0,0 +1,67 @@
+//
+// Copyright 2016 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <uhd/usrp/fe_connection.hpp>
+#include <uhd/exception.hpp>
+#include <boost/regex.hpp>
+#include <uhd/utils/math.hpp>
+
+using namespace uhd::usrp;
+
+fe_connection_t::fe_connection_t(
+    sampling_t sampling_mode, bool iq_swapped,
+    bool i_inverted, bool q_inverted, double if_freq
+) : _sampling_mode(sampling_mode), _iq_swapped(iq_swapped),
+    _i_inverted(i_inverted), _q_inverted(q_inverted), _if_freq(if_freq)
+{
+}
+
+fe_connection_t::fe_connection_t(const std::string& conn_str, double if_freq) {
+    static const boost::regex conn_regex("([IQ])(b?)(([IQ])(b?))?");
+    boost::cmatch matches;
+    if (boost::regex_match(conn_str.c_str(), matches, conn_regex)) {
+        if (matches[3].length() == 0) {
+            //Connection in {I, Q, Ib, Qb}
+            _sampling_mode = REAL;
+            _iq_swapped = (matches[1].str() == "Q");
+            _i_inverted = (matches[2].length() != 0);
+            _q_inverted = false;    //IQ is swapped after inversion
+        } else {
+            //Connection in {I(b?)Q(b?), Q(b?)I(b?), I(b?)I(b?), Q(b?)Q(b?)}
+            _sampling_mode = (matches[1].str() == matches[4].str()) ? HETERODYNE : QUADRATURE;
+            _iq_swapped = (matches[1].str() == "Q");
+            size_t i_idx = _iq_swapped ? 5 : 2, q_idx = _iq_swapped ? 2 : 5;
+            _i_inverted = (matches[i_idx].length() != 0);
+            _q_inverted = (matches[q_idx].length() != 0);
+
+            if (_sampling_mode == HETERODYNE and _i_inverted != _q_inverted) {
+                throw uhd::value_error("Invalid connection string: " + conn_str);
+            }
+        }
+        _if_freq = if_freq;
+    } else {
+        throw uhd::value_error("Invalid connection string: " + conn_str);
+    }
+}
+
+bool uhd::usrp::operator==(const fe_connection_t &lhs, const fe_connection_t &rhs){
+    return ((lhs.get_sampling_mode() == rhs.get_sampling_mode()) and
+            (lhs.is_iq_swapped() == rhs.is_iq_swapped()) and
+            (lhs.is_i_inverted() == rhs.is_i_inverted()) and
+            (lhs.is_q_inverted() == rhs.is_q_inverted()) and
+            uhd::math::frequencies_are_equal(lhs.get_if_freq(), rhs.get_if_freq()));
+}