utils: cast: Add from_str() typecast

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

1 files changed, 20 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 */