FlatGroup.h

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#pragma once

#include <iterator>

#include <OnixS/FIXEngine/Compiler.h>
#include <OnixS/FIXEngine/FIX/FlatMessage.h>

namespace OnixS {
namespace FIX {
ONIXS_FIXENGINE_API_DECL(class, FlatMessage);
ONIXS_FIXENGINE_API_DECL(class, FlatGroup);

/// A single instance of the FIX Repeating Group. Provides an access
/// to the fields of a particular repeating group instance.
class ONIXS_FIXENGINE_API FlatGroupInstance
{
public:

    /// Looks for a field using the given tag number.
    /// @return A valid reference in case of success, otherwise - an invalid one.
    FlatFieldRef find(Tag) const;

    /// Provides an access to a field value by the given temporary reference.
    StringRef operator[](const FlatFieldRef &) const;

    /// Returns the reference to a repeating group - if exists.
    ///
    /// @param numberOfInstancesRef A reference of
    /// the field that defines the number of instances
    /// in this repeating group (the NoXXX field).
    ///
    /// @throw std::exception if the given field does not contain the number of instances.
    FlatGroup getGroup(const FlatFieldRef & numberOfInstancesRef) const;

private:

    friend class MessageOperator;

    FlatGroupInstance(const FlatMessage *, const StringRef &, const FlatGroupInstance * parent);
    FlatGroupInstance(const FlatMessage *, const FlatGroupInstance *, const FlatGroupInstance * parent);

    const FlatMessage * container_;
    Tag parentLeadingTag_;
    FlatField leadingField_;
};

/// Encapsulates operations over the FIX Repeating Group.
///
/// The repeating group represents an array of repeating group instances,
/// This class exposes corresponding services to manipulate the array
/// of repeating group instances. Similar to the OnixS::FIX::FlatGroupInstance
/// it behaves like a pointer/reference to the underlying data. It's
/// a light-weight object which just wraps the internal data.
///
/// The group remains valid until corresponding group fields are updated.
class ONIXS_FIXENGINE_API FlatGroup
{
public:

    /// Returns the number of instances in the repeating group.
    size_t size() const { return groupSize_; }

    /// Returns the StringRef value of the repeating group field.
    StringRef groupFieldValue() const { return StringRef(groupFieldValue_, groupFieldValueSize_); }

    /// The constant iterator to iterate over all group instances in the repeating group.
    class ONIXS_FIXENGINE_API ConstIterator
    {
    public:

        typedef std::forward_iterator_tag iterator_category;
        typedef FlatGroupInstance value_type;
        typedef std::ptrdiff_t difference_type;
        typedef FlatGroupInstance * pointer;
        typedef FlatGroupInstance & reference;

        /// Initializes an iterator by a first group instance from which you need to iterate.
        ConstIterator(const FlatGroup *, size_t);

        const FlatGroupInstance & operator*() const {
            return currentGroupInstance_;
        }

        const FlatGroupInstance * operator->() const {
            return &currentGroupInstance_;
        }

        bool operator == (const ConstIterator &) const;
        bool operator != (const ConstIterator &) const;

        ConstIterator & operator ++();

    private:
        /// The FlatMessage instance to iterate.
        const FlatGroup * container_;

        /// The current group instance index.
        size_t currentGroupInstanceIndex_;

        /// The current group instance.
        FlatGroupInstance currentGroupInstance_;
    };

    /// Returns the iterator to the first group instance in the group.
    ConstIterator begin() const;

    /// Returns the iterator to the group instance after the last one in the group.
    ConstIterator end() const;

private:

    friend class MessageOperator;

    FlatGroup(const FlatMessage *, FlatFieldRef, const FlatGroupInstance *);

    const FlatMessage * container_;

    const FlatGroupInstance * parent_;

    const char * groupFieldValue_;

    size_t groupFieldValueSize_;

    size_t groupSize_;
};

}
}