utils: cast: Add from_str() typecast

This is the inverse to std::to_string(), and we can overload it with
UHD-internal types.

4 files changed, 68 insertions, 1 deletions

diff --git a/host/include/uhd/utils/cast.hpp b/host/include/uhd/utils/cast.hpp
index d6d86d119..fd591dae7 100644
--- a/host/include/uhd/utils/cast.hpp
+++ b/host/include/uhd/utils/cast.hpp
@@ -1,6 +1,7 @@
 //
 // Copyright 2014-2015 Ettus Research LLC
 // Copyright 2018 Ettus Research, a National Instruments Company
+// Copyright 2019 Ettus Research, a National Instruments Brand
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
@@ -9,6 +10,7 @@
 #define INCLUDED_UHD_UTILS_CAST_HPP
 
 #include <uhd/config.hpp>
+#include <uhd/exception.hpp>
 #include <sstream>
 #include <string>
 
@@ -18,7 +20,8 @@ namespace uhd { namespace cast {
 // Example:
 //     uint16_t x = hexstr_cast<uint16_t>("0xDEADBEEF");
 // Uses stringstream.
-template <typename T> UHD_INLINE T hexstr_cast(const std::string& in)
+template <typename T>
+inline T hexstr_cast(const std::string& in)
 {
     T x;
     std::stringstream ss;
@@ -27,6 +30,22 @@ template <typename T> UHD_INLINE T hexstr_cast(const std::string& in)
     return x;
 }
 
+//! Generic cast-from-string function
+template <typename data_t>
+data_t from_str(const std::string&)
+{
+    throw uhd::runtime_error("Cannot convert from string!");
+}
+
+template <>
+UHD_API double from_str(const std::string& val);
+
+template <>
+UHD_API int from_str(const std::string& val);
+
+template <>
+UHD_API std::string from_str(const std::string& val);
+
 }} // namespace uhd::cast
 
 #endif /* INCLUDED_UHD_UTILS_CAST_HPP */
diff --git a/host/lib/utils/CMakeLists.txt b/host/lib/utils/CMakeLists.txt
index b4dd72c94..74b292fbb 100644
--- a/host/lib/utils/CMakeLists.txt
+++ b/host/lib/utils/CMakeLists.txt
@@ -219,6 +219,7 @@ set_source_files_properties(
 # Append sources
 ########################################################################
 LIBUHD_APPEND_SOURCES(
+    ${CMAKE_CURRENT_SOURCE_DIR}/cast.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/csv.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/config_parser.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/compat_check.cpp
diff --git a/host/lib/utils/cast.cpp b/host/lib/utils/cast.cpp
new file mode 100644
index 000000000..635d844ee
--- /dev/null
+++ b/host/lib/utils/cast.cpp
@@ -0,0 +1,39 @@
+//
+// Copyright 2019 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#include <uhd/utils/cast.hpp>
+
+using namespace uhd;
+
+template <>
+double cast::from_str(const std::string& val)
+{
+    try {
+        return std::stod(val);
+    } catch (std::invalid_argument&) {
+        throw uhd::runtime_error(std::string("Cannot convert `") + val + "' to double!");
+    } catch (std::out_of_range&) {
+        throw uhd::runtime_error(std::string("Cannot convert `") + val + "' to double!");
+    }
+}
+
+template <>
+int cast::from_str(const std::string& val)
+{
+    try {
+        return std::stoi(val);
+    } catch (std::invalid_argument&) {
+        throw uhd::runtime_error(std::string("Cannot convert `") + val + "' to int!");
+    } catch (std::out_of_range&) {
+        throw uhd::runtime_error(std::string("Cannot convert `") + val + "' to int!");
+    }
+}
+
+template <>
+std::string cast::from_str(const std::string& val)
+{
+    return val;
+}
diff --git a/host/tests/cast_test.cpp b/host/tests/cast_test.cpp
index 296574b48..9f7941a1d 100644
--- a/host/tests/cast_test.cpp
+++ b/host/tests/cast_test.cpp
@@ -20,3 +20,11 @@ BOOST_AUTO_TEST_CASE(test_mac_addr)
               << "?" << std::endl;
     BOOST_CHECK_EQUAL(x, correct_result);
 }
+
+BOOST_AUTO_TEST_CASE(test_from_str)
+{
+    using namespace uhd::cast;
+    BOOST_CHECK_EQUAL(5.0, from_str<double>("5.0"));
+    BOOST_CHECK_EQUAL(23, from_str<int>("23"));
+    BOOST_CHECK_EQUAL("foo", from_str<std::string>("foo"));
+}