MultiContainer.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
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// protected by copyright law and international copyright treaties.
//
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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 <cassert>

#include <vector>
#include <algorithm>

#include <OnixS/CME/MDH/String.h>
#include <OnixS/CME/MDH/FIX/Tag.h>

ONIXS_CMEMDHFIX_NAMESPACE_BEGIN

/// Represents a pair of a tag and a value.
class ONIXS_CMEMDH_LTWT TagValue
{
    Tag tag_;
    StrRef value_;

public:
    /// Alias for the value type.
    typedef StrRef Value;

    /// Initialies instance with
    /// zero tag and empty value.
    TagValue()
        : tag_(0)
        , value_()
    {
    }

    /// Initializes instance according
    /// to the given attributes.
    TagValue(Tag tag, const Value& value)
        : tag_(tag)
        , value_(value)
    {
    }

    /// Tag component of the pair.
    Tag tag() const
    {
        return tag_;
    }

    /// Updates tag component.
    void tag(Tag tag)
    {
        tag_ = tag;
    }

    /// Value component of the pair.
    const Value& value() const
    {
        return value_;
    }

    /// Updates value component.
    void value(const Value& value)
    {
        value_ = value;
    }

    /// Updates value component.
    void value(const Char* data, size_t size)
    {
        value_.reset(data, size);
    }
};

/// Serializes the given tag-value pair.
ONIXS_CMEMDH_EXPORTED
void toStr(std::string&, const TagValue&);

/// Serializes the given tag-value pair.
inline std::string toStr(const TagValue& tagValue)
{
    std::string str;

    toStr(str, tagValue);

    return str;
}

//

/// Sequence of tag-value pairs.
typedef std::vector<TagValue> TagValues;

/// Iterator over the tag-value sequence.
typedef TagValues::iterator TagValueIterator;

/// Constant iterator over the tag-value sequence.
typedef TagValues::const_iterator TagValueConstIterator;

//

/// Functor to be used in algorithms to find
/// tag-value pair in collections by tag component.
class ONIXS_CMEMDH_LTWT TagValueSelector
{
    Tag tag_;

public:
    /// Initializes functor with the given tag.
    explicit TagValueSelector(Tag tag)
        : tag_(tag)
    {
    }

    /// Checks whether tag component of the given
    /// tag-value matches value stored by the functor.
    bool operator()(const TagValue& tagValue) const
    {
        return (tagValue.tag() == tag_);
    }
};

//

/// Iterator over tag-value pairs having the same tag value.
class ONIXS_CMEMDH_LTWT TagValueSelectionIterator
{
    const TagValues* container_;
    TagValueConstIterator ref_;

public:
    /// Initializes the iterator pointing to nothing.
    TagValueSelectionIterator()
        : container_(ONIXS_CMEMDH_NULLPTR)
        , ref_()
    {
    }

    /// Initializes the instance to iterate tag-values
    /// with the given tag value for the given collection.
    TagValueSelectionIterator(const TagValues& container, Tag selection)
        : container_(&container)
        , ref_(std::find_if(container.begin(), container.end(), TagValueSelector(selection)))
    {
    }

    /// Indicates whether iterator refers
    /// to a valid tag-value instance.
    operator bool() const
    {
        return (container_ && ref_ != container_->end());
    }

    /// Returns instance of the tag-value
    /// pair referenced by the given instance.
    const TagValue& operator*() const
    {
        assert(static_cast<bool>(*this));

        return *ref_;
    }

    /// Advances the given instance to the next
    /// tag-value instance in the selection or
    /// invalidates the instance if no more tag-value
    /// pairs are available in the selection.
    TagValueSelectionIterator& operator++()
    {
        assert(static_cast<bool>(*this));

        const Tag selection = ref_->tag();

        ref_ = std::find_if(++ref_, container_->end(), TagValueSelector(selection));

        return *this;
    }
};

//

/// Sequence of tag-value pairs preserving order of
/// pairs and allowing presence of multiple tag-value
/// pairs with the same tag value.
///
/// Primarily, designed to provide lightweight service
/// to transform serialized FIX messages into structural
/// presentation for further field access and other
/// manipulations over stored data.
class ONIXS_CMEMDH_LTWT MultiContainer
{
    TagValues tagValues_;

    // Builds sequence of tag-value pairs
    // from the given FIX (tag=value) string.
    ONIXS_CMEMDH_LTWT_EXPORTED
    static void deserialize(TagValues&, const Char*, size_t);

public:
    /// Alias for tag component which
    /// serves like an entry key.
    typedef Tag Key;

    /// Alias for value type.
    typedef TagValue::Value Value;

    /// Iterator over container items.
    typedef TagValues::const_iterator Iterator;

    /// Iterator over items having the same tag value.
    typedef TagValueSelectionIterator SelectionIterator;

    /// Initializes an empty instance.
    MultiContainer() {}

    /// Finalizes the instance.
    ~MultiContainer() {}

    /// Returns iterator pointing to
    /// the first item of the container.
    Iterator begin() const
    {
        return tagValues_.begin();
    }

    /// Returns iterator pointing to
    /// the item beyond the last one.
    Iterator end() const
    {
        return tagValues_.end();
    }

    /// Returns iterator pointing to the
    /// first (of possibly multiple) item
    /// having the given key (tag) value.
    Iterator first(Key tag) const
    {
        return std::find_if(tagValues_.begin(), tagValues_.end(), TagValueSelector(tag));
    }

    /// Allows to iterate all items in the
    /// container having the given tag value.
    SelectionIterator all(Key tag) const
    {
        return SelectionIterator(tagValues_, tag);
    }

    /// Full-fill collection from the FIX
    /// (tag=value) string presentation.
    void deserialize(const Char* fixStr, size_t fixSize)
    {
        tagValues_.clear();

        deserialize(tagValues_, fixStr, fixSize);
    }
};

/// Finds a tag-value entry in the given collection
/// by the given tag and returns its value component.
inline MultiContainer::Value valueOrDefault(
    const MultiContainer& container,
    Tag tag,
    const MultiContainer::Value& defaultValue = MultiContainer::Value()
)
{
    const MultiContainer::Iterator result = container.first(tag);

    if (result != container.end())
    {
        return result->value();
    }

    return defaultValue;
}

/// Finds a tag-value entry in the given collection
/// by the given tag and returns its value component
/// transformed into a number.
///
/// Throws an exception if a value is either absent or
/// can't be transformed into a number of the given type.
template <class Number>
bool value(Number& number, const MultiContainer& container, Tag tag)
{
    const MultiContainer::Value strValue = valueOrDefault(container, tag);

    return fromStr(number, strValue.items(), strValue.size());
}

/// Finds a tag-value entry in the given collection
/// by the given tag and returns its value component
/// transformed into a number of the given type.
///
/// If value is absent, then returns the default one.
/// If value is found, but can't be transformed into a
/// number, then an exception is trown.
template <class Number>
bool valueOrDefault(Number& number, const MultiContainer& container, Tag tag, Number defaultValue = Number())
{
    const MultiContainer::Value strValue = valueOrDefault(container, tag);

    if (strValue.empty())
    {
        number = defaultValue;

        return true;
    }

    return fromStr(number, strValue.items(), strValue.size());
}

//

/// Serializes the given tag-value pair.
ONIXS_CMEMDH_EXPORTED
void toStr(std::string&, const MultiContainer&);

/// Serializes the given tag-value pair.
inline std::string toStr(const MultiContainer& container)
{
    std::string str;

    toStr(str, container);

    return str;
}

//

ONIXS_CMEMDHFIX_NAMESPACE_END