FieldValueRef.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 OnixS Software
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* 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.
*
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* the terms of the Agreement is a violation of copyright law.
*/

#pragma once

#include <OnixS/FIXEngine/FIX/StringRef.h>
#include <OnixS/FIXEngine/FIX/Timestamp.h>

namespace OnixS {
namespace FIX {
ONIXS_FIXENGINE_API_DECL(class, Message);
ONIXS_FIXENGINE_API_DECL(class, Group);

/// Implements a concept of a read-only
/// reference to a FIX field value.
class
    ONIXS_FIXENGINE_API
    FieldValueRef
{
public:
    /// The uninitialized value.
    FieldValueRef();

    /// The shallow copy from another one.
    FieldValueRef(const FieldValueRef & other);

    /// Indicated whether the instance
    /// refers to a valid value.
    bool valid() const;

    /// Return the string presentation
    /// of the value being referenced.
    operator std::string() const;

    /// Compares with another instance for equality.
    bool operator == (const FieldValueRef &) const;

    /// Compares with another instance for inequality.
    bool operator != (const FieldValueRef &) const;

    /// Compares the string presentation for
    /// equality with given text reference.
    bool operator == (const StringRef &) const;

    /// Compares the string presentation for
    /// equality with the given text reference.
    bool operator != (const StringRef &) const;

    /// Converts the field value into the whole number.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toNumber(Int32 &) const;

    /// Converts the field value into the whole number.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toNumber(UInt32 &) const;

    /// Converts the field value into the whole number.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toNumber(Int64 &) const;

    /// Converts the field value into the whole number.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toNumber(UInt64 &) const;

    /// Converts the field value into the floating point value.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toNumber(Double &) const;

    /// Converts the field value into the floating point value.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toNumber(Decimal &) const;

    /// Converts the field value into the timestamp of the requested format.
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool
    toTimestamp(
        Timestamp &,
        TimestampFormat::Enum =
            TimestampFormat::YYYYMMDDHHMMSSNsec) const;


    /// Converts the field value into the timespan
    ///
    /// @return false if the conversion fails.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool
    toTimeSpan(
        TimeSpan&, TimeSpanFormat::Enum = TimeSpanFormat::HHMMSSMsec) const;

    /// If the value represents a text, returns a reference to it.
    ///
    /// @return false if the conversion fails (for example,
    /// the stored value is the whole number assigned to a field
    /// using the OnixS::FIX::FieldSet::setV member), otherwise - true.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toStringRef(StringRef &) const;

    /// If the value represents a text, returns a reference to it.
    ///
    /// @return An empty StringRef if the conversion fails (for example,
    /// the stored value is the whole number assigned to a field
    /// using the OnixS::FIX::FieldSet::setV member), otherwise - valid StringRef.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    StringRef toStringRef() const;

    /// If the value represent a one-char text,
    /// copies it into the given variable.
    ///
    /// @return false if the conversion fails (for example,
    /// the stored value is the whole number assigned to a field
    /// using the OnixS::FIX::FieldSet::setV member).
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toChar(char &) const;

    /// If a repeating group is associated with
    /// the field, allows to get an instance of it.
    ///
    /// @return false if no group is associated with the field.
    ///
    /// @warning Due to performance considerations
    /// doesn't check whether an instance refers to a valid
    /// value. Use the OnixS::FIX::FieldValueRef::operator bool()
    /// member to check an instance for a validness.
    bool toGroup(Group &) const;

    /// Appends a copy of a text presentation to the std::string.
    void toString(std::string &) const;

    /// Return the string presentation of the field value.
    std::string toString() const;

    /// Updates an instance to refer to another field value.
    /// @warning Does NOT perform a deep copy of field values.
    /// Just updates a reference to point to the value of other field.
    FieldValueRef & operator = (const FieldValueRef &);

    /// Swaps two references.
    void swap(FieldValueRef & other);

private:
    friend class MessageOperator;

    const void * impl_;

    const Message * container_;

    FieldValueRef(
        const Message *,
        const void *);
};

inline StringRef FieldValueRef::toStringRef() const
{
    StringRef result;

    if(toStringRef(result))
        return result;
    else
        return StringRef();
}

inline
FieldValueRef::
operator std::string() const
{
    std::string str;

    toString(str);

    return str;
}

inline
std::string
FieldValueRef::toString() const
{
    std::string str;

    toString(str);

    return str;
}

// More comparison operators.

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

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

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

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

// More comparison operators.

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

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

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

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