MultiContainer.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
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// 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/ConflatedUDP/String.h>
#include <OnixS/CME/ConflatedUDP/FIX/Tag.h>

ONIXS_CONFLATEDUDPFIX_NAMESPACE_BEGIN

/// Represents a pair of a tag and a value. 
ONIXS_CONFLATEDUDP_LTWT_CLASS 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_CONFLATEDUDP_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 algorythms to find 
/// tag-value pair in collections by tag component. 
ONIXS_CONFLATEDUDP_LTWT_CLASS 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. 
ONIXS_CONFLATEDUDP_LTWT_CLASS 
TagValueSelectionIterator
{
    const TagValues* container_;
    TagValueConstIterator ref_;

public:
    /// Initializes the interator pointing to nothing. 
    TagValueSelectionIterator()
        : container_(NULL)
        , 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 furhter field access and other 
/// manipulations over stored data. 
ONIXS_CONFLATEDUDP_LTWT_CLASS MultiContainer
{
    TagValues tagValues_;

    // Builds sequence of tag-value pairs 
    // from the given FIX (tag=value) string. 
    ONIXS_CONFLATEDUDP_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_CONFLATEDUDP_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_CONFLATEDUDPFIX_NAMESPACE_END