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**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Creator.
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
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#pragma once

#include <utils/hostosinfo.h>
#include <utils/smallstringview.h>

#include <algorithm>
#include <vector>

namespace ClangBackEnd {

template <char WindowsSlash>
class AbstractFilePathView : public Utils::SmallStringView
{
public:
    constexpr AbstractFilePathView() = default;
    explicit AbstractFilePathView(const char *const string, const size_type size) noexcept
        : AbstractFilePathView{Utils::SmallStringView{string, size}}
    {
    }

    explicit AbstractFilePathView(Utils::SmallStringView filePath)
        : Utils::SmallStringView(filePath)
        , m_slashIndex(lastSlashIndex(filePath))
    {
    }

    template <typename String,
              typename = std::enable_if_t<std::is_lvalue_reference<String>::value>>
    explicit AbstractFilePathView(String &&filePath)
        : AbstractFilePathView(filePath.data(), filePath.size())
    {
    }

    template<size_type Size>
    AbstractFilePathView(const char(&string)[Size]) noexcept
        : AbstractFilePathView(string, Size - 1)
    {
        static_assert(Size >= 1, "Invalid string literal! Length is zero!");
    }

    Utils::SmallStringView toStringView() const
    {
        return *this;
    }

    std::ptrdiff_t slashIndex() const
    {
        return m_slashIndex;
    }

    Utils::SmallStringView directory() const noexcept
    {
        return mid(0, std::size_t(std::max(std::ptrdiff_t(0), m_slashIndex)));
    }

    Utils::SmallStringView name() const noexcept
    {
        return mid(std::size_t(m_slashIndex + 1),
                   std::size_t(std::ptrdiff_t(size()) - m_slashIndex - std::ptrdiff_t(1)));
    }

    static
    std::ptrdiff_t lastSlashIndex(Utils::SmallStringView filePath)
    {
        constexpr char separator = Utils::HostOsInfo::isWindowsHost() ? WindowsSlash : '/';
        auto foundReverse = std::find(filePath.rbegin(), filePath.rend(), separator);
        auto found = foundReverse.base();

        auto distance = std::distance(filePath.begin(), found);

        return distance - 1;
    }

    friend bool operator==(const AbstractFilePathView &first, const AbstractFilePathView &second)
    {
        return first.toStringView() == second.toStringView();
    }

private:
    std::ptrdiff_t m_slashIndex = -1;
};

using FilePathView = AbstractFilePathView<'/'>;
using NativeFilePathView = AbstractFilePathView<'\\'>;
using FilePathViews = std::vector<FilePathView>;
using NativeFilePathViews = std::vector<NativeFilePathView>;
}
