String.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 
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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 
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// amendments to this copyright notice, are expressly prohibited.
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#pragma once

#include <OnixS/CboeCFE/MarketData/Pitch/Compiler.h>

#include <cstddef>
#include <cstring>
#include <string>
#include <stdexcept>

#include <algorithm>
#include <ostream>

namespace OnixS
{
    namespace CboeCFE
    {
        namespace MarketData
        {
            namespace Pitch
            {
                /// Character type alias.
                typedef char Char;

                /// Provides efficient way of accessing text-based FIX field values.
                class StrRef
                {
                public:
                    /// STL-like iterator.
                    typedef const Char* Iterator;

                    /// Initializes blank instance.
                    StrRef()
                    ONIXS_BATS_PITCH_NOTHROW
                        : items_(ONIXS_BATS_PITCH_NULLPTR)
                        , size_(0)
                    {
                    }

                    /// Full initialization.
                    StrRef(
                        const Char* chars,
                        size_t size)
                        ONIXS_BATS_PITCH_NOTHROW
                        : items_(chars)
                        , size_(size)
                    {
                    }

                    template <size_t Size>
                    explicit
                    ONIXS_BATS_PITCH_CONSTEXPR
                    StrRef(const char (&value)[Size])
                    ONIXS_BATS_PITCH_NOTHROW
                        : items_(value)
                        , size_(Size - 1)
                    {
                    }

                    /// Initializes as clone of other instance.
                    /// Data referenced by clone is not copied.
                    /// Instead both instances will refer to same
                    /// text segment.
                    StrRef(
                        const StrRef& other)
                        ONIXS_BATS_PITCH_NOTHROW
                        : items_(other.items_)
                        , size_(other.size_)
                    {
                    }

                    /// Indicates whether array of zero length.
                    bool empty() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return (0 == size_);
                    }

                    /// Read-only content.
                    const Char* items() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return items_;
                    }

                    /// Number of chars.
                    size_t size() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return size_;
                    }

                    /// STL-like begin().
                    Iterator begin() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return items_;
                    }

                    /// STL-like end().
                    Iterator end() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        return (items_ + size_);
                    }

                    /// Resets reference to nothing.
                    void reset()
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        reset(ONIXS_BATS_PITCH_NULLPTR, 0);
                    }

                    /// Updates data being referenced.
                    void
                    reset(
                        const Char* chars,
                        size_t size)
                        ONIXS_BATS_PITCH_NOTHROW
                    {
                        items_ = chars;
                        size_ = size;
                    }

                    const Char&
                    operator [](
                        size_t index) const
                    {
                        return items_[index];
                    }

                    const Char&
                    at(
                        size_t index) const
                    {
                        if (index < size_)
                            return items_[index];

                        throw std::invalid_argument("index");
                    }

                    /// Reinitializes from another instance.
                    StrRef&
                    operator =(
                        const StrRef& other)
                                ONIXS_BATS_PITCH_NOTHROW
                    {
                        items_ = other.items_;
                        size_ = other.size_;

                        return *this;
                    }

                    /// Swaps content with other instance.
                    void
                    swap(
                        StrRef& other)
                        ONIXS_BATS_PITCH_NOTHROW
                    {
                        std::swap(items_, other.items_);
                        std::swap(size_, other.size_);
                    }


                    // Get trimmed presentation of the current string
                    StrRef trim() const
                    ONIXS_BATS_PITCH_NOTHROW
                    {
                        size_t length = size();

                        while(length > 0 && isspace(operator[](length - 1)))
                            --length;

                        return StrRef(items(), length);
                    }

                private:
                    /// Items being referenced.
                    const Char* items_;

                    /// Number of chars being referenced.
                    size_t size_;
                };

                /// Constructs StrRef instance over std::string content.
                inline
                    StrRef
                    toStrRef(
                        const std::string& str)
                {
                    return StrRef(str.data(), str.size());
                }

                /// Initializes instance from zero-terminated/C-like string.
                inline
                    StrRef
                    toStrRef(
                        const Char* cStr)
                {
                    return
                        StrRef(
                            cStr,
                            cStr
                            ? strlen(cStr)
                            : 0
                        );
                }

                /// Constructs std::string instance from StrRef one. 
                inline
                    std::string
                    toStr(
                        const StrRef& ref)
                {
                    return std::string(ref.items(), ref.size());
                }

                /// Appends text referenced by StrRef to given std::string instance. 
                inline
                    void
                    toStr(
                        std::string& str,
                        const StrRef& ref)
                {
                    str.append(ref.items(), ref.size());
                }

                /// Constructs std::string from a character. 
                inline
                    std::string
                    toStr(
                        Char character)
                {
                    return std::string(1, character);
                }

                /// Appends character to given std::string instance. 
                inline
                    void
                    toStr(
                        std::string& str,
                        Char character)
                {
                    str.append(1, character);
                }

                /// Appends one string another one. 
                inline
                    void
                    toStr(
                        std::string& str,
                        const std::string& value)
                {
                    str.append(value);
                }

                /// Compares StrRef instance with another one.
                inline
                    bool
                    operator ==(
                        const StrRef& left,
                        const StrRef& right)
                {
                    return (
                        left.size() == right.size()
                        &&
                        0 == memcmp(
                            left.items(), right.items(), left.size()));
                }

                /// Compares with another instance.
                inline
                    bool
                    operator !=(
                        const StrRef& left,
                        const StrRef& right)
                {
                    return !(left == right);
                }

                /// Compares StrRef with std::string. 
                inline
                    bool
                    operator ==(
                        const StrRef& ref,
                        const std::string& str)
                {
                    return ref == toStrRef(str);
                }

                /// Compares StrRef with std::string. 
                inline
                    bool
                    operator !=(
                        const StrRef& ref,
                        const std::string& str)
                {
                    return ref != toStrRef(str);
                }

                /// Compares StrRef with std::string. 
                inline
                    bool
                    operator ==(
                        const std::string& str,
                        const StrRef& ref)
                {
                    return ref == toStrRef(str);
                }

                /// Compares StrRef with std::string. 
                inline
                    bool
                    operator !=(
                        const std::string& str,
                        const StrRef& ref)
                {
                    return ref != toStrRef(str);
                }

                /// Compares StrRef with zero-terminated/C-like string. 
                inline
                    bool
                    operator ==(
                        const StrRef& ref,
                        const Char* str)
                {
                    return ref == toStrRef(str);
                }

                /// Compares StrRef with zero-terminated/C-like string. 
                inline
                    bool
                    operator !=(
                        const StrRef& ref,
                        const Char* str)
                {
                    return ref != toStrRef(str);
                }

                /// Compares StrRef with zero-terminated/C-like string. 
                inline
                    bool
                    operator ==(
                        const Char* str,
                        const StrRef& ref)
                {
                    return ref == toStrRef(str);
                }

                /// Compares StrRef with zero-terminated/C-like string. 
                inline
                    bool
                    operator !=(
                        const Char* str,
                        const StrRef& ref)
                {
                    return ref != toStrRef(str);
                }

                /// Establishes order over string refs.
                inline
                    bool
                    operator <(
                        const StrRef& left,
                        const StrRef& right)
                {
                    ptrdiff_t
                        compareResult =
                        memcmp(
                            left.items(),
                            right.items(),
                            left.size() < right.size()
                            ? left.size()
                            : right.size());

                    if (0 == compareResult)
                    {
                        compareResult =
                            static_cast<ptrdiff_t>(
                                left.size() - right.size());
                    }

                    return (0 > compareResult);
                }

                /// Establishes order over string refs.
                inline
                    bool
                    operator >(
                        const StrRef& left,
                        const StrRef& right)
                {
                    return (right < left);
                }

                /// StrRef serialization operator.
                inline
                    std::ostream&
                    operator <<(
                        std::ostream& stream,
                        const StrRef& text)
                {
                    stream.write(text.items(), text.size());

                    return stream;
                }

            }
        }
    }
}