Added support for the comms::option::def::DisplayOffset option.

include/comms/field/IntValue.h

@@ -48,6 +48,7 @@ namespace field
 ///     @li @ref comms::option::def::AvailableLengthLimit
 ///     @li @ref comms::option::def::DefaultValueInitialiser or @ref comms::option::def::DefaultNumValue.
 ///     @li comms::option::def::EmptySerialization
+///     @li @ref comms::option::def::DisplayOffset
 ///     @li @ref comms::option::def::FailOnInvalid
 ///     @li @ref comms::option::def::FieldType
 ///     @li @ref comms::option::def::FixedBitLength
@@ -183,7 +184,14 @@ class IntValue : public details::AdaptBasicFieldT<basic::IntValue<TFieldBase, T>
     static constexpr bool hasFixedValue()
     {
         return ParsedOptions::HasFixedValue;
-    }         
+    }      
+
+    /// @brief Compile time inquiry of whether @ref comms::option::def::DisplayOffset option
+    ///     has been used.
+    static constexpr bool hasDisplayOffset()
+    {
+        return ParsedOptions::HasDisplayOffset;
+    }                
 
     /// @brief Scales value according to ratio specified in provided
     ///     @ref comms::option::def::ScalingRatio option.
@@ -258,6 +266,23 @@ class IntValue : public details::AdaptBasicFieldT<basic::IntValue<TFieldBase, T>
         BaseImpl::setValue(std::forward<U>(val));
     }        
 
+    /// @brief Get display value
+    /// @details Retrieving value by taking into account the display offset provided by the @ref comms::option::def::DisplayOffset option
+    ///     if such was used.
+    ValueType getDisplayValue() const
+    {
+        return static_cast<ValueType>(getValue() + BaseImpl::displayOffset());
+    }
+
+    /// @brief Set display value
+    /// @details Updating inner value by taking into account the display offset provided by the @ref comms::option::def::DisplayOffset option
+    ///     if such was used.
+    template <typename U>
+    void setDisplayValue(U&& val)
+    {
+        setValue(val - BaseImpl::displayOffset());
+    }
+
     /// @brief Get maximal numeric value the field can hold.
     static constexpr ValueType maxValue()
     {

include/comms/field/adapter/DisplayOffset.h

@@ -0,0 +1,44 @@
+//
+// Copyright 2019 - 2024 (C). Alex Robenko. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+#include <cstdint>
+#include <type_traits>
+
+namespace comms
+{
+
+namespace field
+{
+
+namespace adapter
+{
+
+
+template <std::intmax_t TOffset, typename TBase>
+class DisplayOffset : public TBase
+{
+    using BaseImpl = TBase;
+public:
+    using DisplayOffsetType = typename TBase::DisplayOffsetType;
+
+    static constexpr DisplayOffsetType displayOffset()
+    {
+        return static_cast<DisplayOffsetType>(TOffset);
+    }    
+};
+
+}  // namespace adapter
+
+}  // namespace field
+
+}  // namespace comms
+
+
+
+

include/comms/field/basic/IntValue.h

@@ -33,6 +33,7 @@ class IntValue : public TFieldBase
     using SerialisedType = ValueType;
     using ScalingRatio = std::ratio<1, 1>;
     using CommsTag = comms::field::tag::Int;
+    using DisplayOffsetType = typename std::make_signed<ValueType>::type;
 
     IntValue() = default;
 
@@ -130,6 +131,11 @@ class IntValue : public TFieldBase
         BaseImpl::writeData(toSerialised(value_), iter);
     }
 
+    static constexpr DisplayOffsetType displayOffset()
+    {
+        return static_cast<DisplayOffsetType>(0);
+    }
+
 private:
     ValueType value_ = static_cast<ValueType>(0);
 };

include/comms/field/details/AdaptBasicField.h

@@ -139,8 +139,11 @@ class AdaptBasicField
     using SerOffsetAdapted = 
         typename ParsedOptions::template AdaptSerOffset<VersionStorageAdapted>;
 
+    using DisplayOffsetAdapted = 
+        typename ParsedOptions::template AdaptDisplayOffset<SerOffsetAdapted>;
+
     using VersionsRangeAdapted = 
-        typename ParsedOptions::template AdaptVersionsRange<SerOffsetAdapted>;
+        typename ParsedOptions::template AdaptVersionsRange<DisplayOffsetAdapted>;
 
     using FixedLengthLimitAdapted = 
         typename ParsedOptions::template AdaptFixedLengthLimit<VersionsRangeAdapted>;

include/comms/field/details/OptionsParser.h

@@ -75,6 +75,7 @@ class OptionsParser<>
     static constexpr bool HasVariantCustomResetOnDestruct = false;
     static constexpr bool HasVersionDependentMembersForced = false;
     static constexpr bool HasFixedValue = false;
+    static constexpr bool HasDisplayOffset = false;
 
     using UnitsType = void;
     using ScalingRatio = std::ratio<1, 1>;
@@ -194,6 +195,9 @@ class OptionsParser<>
 
     template <typename TField>
     using AdaptFixedValue = TField;
+
+    template <typename TField>
+    using AdaptDisplayOffset = TField;    
 };
 
 template <typename... TOptions>
@@ -808,6 +812,18 @@ class OptionsParser<
     using AdaptFixedValue = comms::field::adapter::FixedValue<TField>;       
 };
 
+template <std::intmax_t TOffset, typename... TOptions>
+class OptionsParser<
+    comms::option::def::DisplayOffset<TOffset>,
+    TOptions...> : public OptionsParser<TOptions...>
+{
+public:
+    static constexpr bool HasDisplayOffset = true;
+    static constexpr std::intmax_t DisplayOffset = TOffset;
+
+    template <typename TField>
+    using AdaptDisplayOffset = comms::field::adapter::DisplayOffset<TOffset, TField>;       
+};
 
 template <typename... TOptions>
 class OptionsParser<

include/comms/field/details/adapters.h

@@ -13,6 +13,7 @@
 #include "comms/field/adapter/CustomRefreshWrap.h"
 #include "comms/field/adapter/CustomWriteWrap.h"
 #include "comms/field/adapter/DefaultValueInitialiser.h"
+#include "comms/field/adapter/DisplayOffset.h"
 #include "comms/field/adapter/EmptySerialization.h"
 #include "comms/field/adapter/ExistsBetweenVersions.h"
 #include "comms/field/adapter/FailOnInvalid.h"

include/comms/options.h

@@ -1243,6 +1243,12 @@ struct HasVersionDependentMembers {};
 /// @brief Remove an ability to update field's value by the client code
 struct FixedValue {};
 
+/// @brief Option used to specify display offset for the @ref comms::field::IntValue field.
+/// @tparam TOffset Display offset.
+/// @headerfile comms/options.h
+template <std::intmax_t TOffset>
+struct DisplayOffset {};
+
 } // namespace def
 
 namespace app

test/Fields2.th

@@ -62,6 +62,7 @@ public:
     void test34();
     void test35();
     void test36();
+    void test37();
 
 private:
     template <typename TField>
@@ -2220,6 +2221,23 @@ void FieldsTestSuite2::test36()
     TS_ASSERT_EQUALS(static_cast<std::size_t>(std::distance(&Buf[0], readIter)), BufSize)
 }
 
+void FieldsTestSuite2::test37()
+{
+    using Field = 
+        comms::field::IntValue<
+            comms::Field<BigEndianOpt>,
+            std::uint16_t,
+            comms::option::def::DisplayOffset<2>
+        >;
+
+    Field field;
+
+    TS_ASSERT_EQUALS(field.getDisplayValue(), 2U);
+    field.setDisplayValue(10U);
+    TS_ASSERT_EQUALS(field.getDisplayValue(), 10U);
+    TS_ASSERT_EQUALS(field.getValue(), 8U);
+}
+
 template <typename TField>
 void FieldsTestSuite2::writeField(
     const TField& field,