Field.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
// This software owned by Onix Solutions Limited [OnixS] and is
// protected by copyright law and international copyright treaties.
//
// Access to and use of the software is governed by the terms of the applicable
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// agreements granting a non-assignable, non-transferable and non-exclusive license
// to use the software for it's own data processing purposes under the terms defined
// in the Agreement.
//
// Except as otherwise granted within the terms of the Agreement, copying or
// reproduction of any part of this source code or associated reference material
// to any other location for further reproduction or redistribution, and any
// amendments to this copyright notice, are expressly prohibited.
//
// Any reproduction or redistribution for sale or hiring of the Software not in
// accordance with the terms of the Agreement is a violation of copyright law.
//

#pragma once

#include <OnixS/CME/iLink3/messaging/TagBased/ValueContainer.h>
#include <OnixS/CME/iLink3/messaging/TagBased/ValueConverters.h>

ONIXS_ILINK3_MESSAGING_TAGBASED_NAMESPACE_BEGIN

/// A field in a tag-based message.
ONIXS_ILINK3_LTWT_CLASS Field
{
public:
    /// Initializes a field with no value.
    Field()
        : value_()
        , converter_(&NullConverter::self())
    {
    }

    /// Tells whether the field has
    /// an associated (non-null) value.
    ONIXS_ILINK3_EXPLICIT ONIXS_ILINK3_NODISCARD operator bool() const ONIXS_ILINK3_NOTHROW
    {
        return (converter_ != &NullConverter::self());
    }

    /// \return a string presentation.
    ONIXS_ILINK3_EXPLICIT ONIXS_ILINK3_NODISCARD operator std::string() const
    {
        return toString();
    }

    /// Compares the presentation for
    /// equality with the given text reference.
    ONIXS_ILINK3_NODISCARD bool operator == (const StrRef& r) const
    {
        ONIXS_ILINK3_CONST_OR_CONSTEXPR size_t bufSize = 512;
        Char buffer[bufSize];

        return this->toString(buffer, bufSize) == r;
    }

    /// Compares the presentation for not equality with given text reference.
    ONIXS_ILINK3_NODISCARD bool operator != (const StrRef& r) const
    {
        return !this->operator==(r);
    }

    /// Casts the stored value to the requested type.
    ///
    /// The value may be converted into the value of the
    /// requested type if a conversion is possible. Otherwise,
    /// an exception is thrown. For example, if the field value
    /// represents a reference to a string (e.g. instance of the
    /// StrRef class), then it can be successfully converted into
    /// a number if the string referred represents a number.
    ///
    /// @throw std::runtime_error if conversion is impossible.
    template
    <
        class Value
    >
    ONIXS_ILINK3_NODISCARD
    typename
    ValueConversion<Value>::Result cast() const
    {
        ValueConversion<Value> convert;

        assert(converter_);

        return convert(*converter_, value_);
    }

    /// Tries to cast the stored value into a value of the StrRef type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toStringRef(StrRef& str) const
    {
        assert(converter_);

        return converter_->convert(str, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Char type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toChar(Char& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Int8 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(Int8& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the UInt8 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(UInt8& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Int16 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(Int16& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the UInt16 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(UInt16& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Int32 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(Int32& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the UInt32 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(UInt32& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Int64 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(Int64& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the UInt64 type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(UInt64& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Decimal type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toNumber(Decimal& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a
    /// value of the Timestamp type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toTimestamp(Timestamp& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a value
    /// of the MaturityMonthYear type.
    ///
    /// \return `false` if the conversion fails.
    ONIXS_ILINK3_NODISCARD bool toMaturityMonthYear(MaturityMonthYear& value) const
    {
        assert(converter_);

        return converter_->convert(value, value_);
    }

    /// Tries to cast the stored value into a value
    /// of the given Enumeration type.
    ///
    /// \return `false` if the conversion fails.
    template<class Enumeration>
    ONIXS_ILINK3_NODISCARD bool toEnumeration(typename Enumeration::Enum& value) const
    {
        typename Enumeration::Base integral;

        assert(converter_);

        if (converter_->convert(integral,value_))
        {
            value = static_cast<typename Enumeration::Enum>(integral);

            return true;
        }

        return false;
    }

    /// Tries to cast the stored value into a value
    /// of the type representing a BitSet.
    ///
    /// \return `false` if the conversion fails.
    template <class BitSet>
    ONIXS_ILINK3_NODISCARD bool toBitSet(BitSet& value) const
    {
        typename BitSet::Bits bits;

        assert(converter_);

        if (converter_->convert(bits, value_))
        {
            value = BitSet(bits);

            return true;
        }

        return false;
    }

    /// \return the text representation.
    ONIXS_ILINK3_NODISCARD std::string toString() const
    {
        std::string str;

        toString(str);

        return str;
    }

    /// Outputs the text representation into the given string.
    void toString(std::string& str) const
    {
        assert(converter_);

        converter_->toStr(str, value_);
    }

    /// \return the text presentation of the value
    /// stored in the given container as a StrRef.
    StrRef toString(Char* buf, size_t size) const
    {
        assert(converter_);

        return converter_->toStr(buf, size, value_);
    }

protected:
    /// Initializes the field.
    explicit Field(const ValueConverter& converter) ONIXS_ILINK3_NOTHROW
        : value_()
        , converter_(&converter)
    {
    }

    /// Exposes the value storage for further value manipulations.
    const ValueContainer& value() const ONIXS_ILINK3_NOTHROW
    {
        return value_;
    }

    /// Exposes the value storage for further value manipulations.
    ValueContainer& value() ONIXS_ILINK3_NOTHROW
    {
        return value_;
    }

private:
    ValueContainer value_;
    const ValueConverter* converter_;
};

inline bool operator == (const Field& ref, const std::string& str)
{
    return ref == StrRef(str);
}

inline bool operator != (const Field& ref, const std::string& str)
{
    return ref != StrRef(str);
}

inline bool operator == (const std::string& str, const Field & ref)
{
    return ref == StrRef(str);
}

inline bool operator != (const std::string& str, const Field& ref)
{
    return ref != StrRef(str);
}

inline bool operator == (const Field& ref, const char* str)
{
    return ref == StrRef(str);
}

inline bool operator != (const Field& ref, const char* str)
{
    return ref != StrRef(str);
}

inline bool operator == (const char* str, const Field& ref)
{
    return ref == StrRef(str);
}

inline bool operator != (const char* str, const Field& ref)
{
    return ref != StrRef(str);
}

/// Serializes into the given stream.
inline std::ostream& operator<<(std::ostream& stream, const Field& field)
{
    return stream << field.toString();
}

ONIXS_ILINK3_MESSAGING_TAGBASED_NAMESPACE_END