// string_token.hpp
// Copyright (c) 2005-2012 Ben Hanson (http://www.benhanson.net/)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file licence_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef LEXERTL_STRING_TOKEN_HPP
#define LEXERTL_STRING_TOKEN_HPP

#include "char_traits.hpp"
#include <ios> // Needed by GCC 4.4
#include <iostream>
#include <string>
#include <utility>
#include <vector>

namespace lexertl
{
template<typename ch_type>
struct basic_string_token
{
    typedef ch_type char_type;
    typedef basic_char_traits<char_type> char_traits;
    typedef typename char_traits::index_type index_type;
    typedef std::pair<index_type, index_type> range;
    typedef std::vector<range> range_vector;
    typedef std::basic_string<char_type> string;
    typedef basic_string_token<char_type> string_token;

    range_vector _ranges;

    basic_string_token () :
        _ranges ()
    {
    }

    basic_string_token (char_type ch_) :
        _ranges ()
    {
        insert (range (ch_, ch_));
    }

    basic_string_token (char_type first_, char_type second_) :
        _ranges ()
    {
        insert (range (first_, second_));
    }

    void clear ()
    {
        _ranges.clear ();
    }

    bool empty () const
    {
        return _ranges.empty ();
    }

    bool any () const
    {
        return _ranges.size () == 1 && _ranges.front ().first == 0 &&
            _ranges.front ().second == char_traits::max_val ();
    }

    bool operator < (const basic_string_token &rhs_) const
    {
        return _ranges < rhs_._ranges;
    }

    bool operator == (const basic_string_token &rhs_) const
    {
        return _ranges == rhs_._ranges;
    }

    bool negatable () const
    {
        std::size_t size_ = 0;
        typename range_vector::const_iterator iter_ = _ranges.begin ();
        typename range_vector::const_iterator end_ = _ranges.end ();

        for (; iter_ != end_; ++iter_)
        {
            size_ += static_cast<std::size_t>(iter_->second) + 1 -
                static_cast<std::size_t>(iter_->first);
        }

        return size_ > static_cast<std::size_t>(char_traits::max_val ()) / 2;
    }

    void swap (basic_string_token &rhs_)
    {
        _ranges.swap (rhs_._ranges);
    }

    void insert (const basic_string_token &rhs_)
    {
        typename range_vector::const_iterator iter_ = rhs_._ranges.begin ();
        typename range_vector::const_iterator end_ = rhs_._ranges.end ();

        for (; iter_ != end_; ++iter_)
        {
            insert (*iter_);
        }
    }

    // Deliberately pass by value - may modify
    typename range_vector::iterator insert (range rhs_)
    {
        bool insert_ = true;
        typename range_vector::iterator iter_ = _ranges.begin ();
        typename range_vector::const_iterator end_ = _ranges.end ();

        while (iter_ != end_)
        {
            // follows current item
            if (rhs_.first > iter_->second)
            {
                if (rhs_.first == iter_->second + 1)
                {
                    // Auto normalise
                    rhs_.first = iter_->first;
                }
                else
                {
                    // No intersection, consider next
                    ++iter_;
                    continue;
                }
            }
            // Precedes current item
            else if (rhs_.second < iter_->first)
            {
                if (rhs_.second == iter_->first - 1)
                {
                    // Auto normalise
                    rhs_.second = iter_->second;
                }
                else
                {
                    // insert here
                    break;
                }
            }
            else
            {
                // overlap (under)
                if (rhs_.first < iter_->first)
                {
                    if (rhs_.second < iter_->second)
                    {
                        rhs_.second = iter_->second;
                    }
                }
                // overlap (over)
                else if (rhs_.second > iter_->second)
                {
                    if (rhs_.first > iter_->first)
                    {
                        rhs_.first = iter_->first;
                    }
                }
                // subset
                else
                {
                    insert_ = false;
                    iter_ = _ranges.end ();
                    break;
                }
            }

            // Code minimisation: this always applies unless we have already
            // exited the loop, or "continue" executed.
            iter_ = _ranges.erase (iter_);
            end_ = _ranges.end ();
        }

        if (insert_)
        {
            iter_ = _ranges.insert(iter_, rhs_);
        }

        return iter_;
    }

    void negate ()
    {
        index_type next_ = 0;
        const index_type max_ = char_traits::max_val ();
        string_token temp_;
        typename range_vector::iterator iter_ = _ranges.begin ();
        typename range_vector::const_iterator end_ = _ranges.end ();
        bool finished_ = false;

        for (; iter_ != end_; ++iter_)
        {
            if (next_ < iter_->first)
            {
                temp_.insert (range (next_, iter_->first - 1));
            }

            if (iter_->second < max_)
            {
                next_ = iter_->second + 1;
            }
            else
            {
                finished_ = true;
                break;
            }
        }

        if (!finished_)
        {
            temp_.insert (range (next_, max_));
        }

        swap (temp_);
    }

    void intersect (basic_string_token &rhs_, basic_string_token &overlap_)
    {
        typename range_vector::iterator lhs_iter_ = _ranges.begin ();
        typename range_vector::const_iterator lhs_end_ = _ranges.end ();
        typename range_vector::iterator rhs_iter_ = rhs_._ranges.begin ();
        typename range_vector::const_iterator rhs_end_ = rhs_._ranges.end ();

        while (lhs_iter_ != lhs_end_ && rhs_iter_ != rhs_end_)
        {
            if (rhs_iter_->first > lhs_iter_->second)
            {
                ++lhs_iter_;
            }
            else if (rhs_iter_->second < lhs_iter_->first)
            {
                ++rhs_iter_;
            }
            else
            {
                range range_;

                if (rhs_iter_->first > lhs_iter_->first)
                {
                    range_.first = rhs_iter_->first;
                }
                else
                {
                    range_.first = lhs_iter_->first;
                }

                if (rhs_iter_->second < lhs_iter_->second)
                {
                    range_.second = rhs_iter_->second;
                }
                else
                {
                    range_.second = lhs_iter_->second;
                }

                adjust (range_, *this, lhs_iter_, lhs_end_);
                adjust (range_, rhs_, rhs_iter_, rhs_end_);
                overlap_.insert (range_);
            }
        }
    }

    void remove (basic_string_token &rhs_)
    {
        typename range_vector::iterator lhs_iter_ = _ranges.begin ();
        typename range_vector::const_iterator lhs_end_ = _ranges.end ();
        typename range_vector::iterator rhs_iter_ = rhs_._ranges.begin ();
        typename range_vector::const_iterator rhs_end_ = rhs_._ranges.end ();

        while (lhs_iter_ != lhs_end_ && rhs_iter_ != rhs_end_)
        {
            if (rhs_iter_->first > lhs_iter_->second)
            {
                ++lhs_iter_;
            }
            else if (rhs_iter_->second < lhs_iter_->first)
            {
                ++rhs_iter_;
            }
            else
            {
                range range_;

                if (rhs_iter_->first > lhs_iter_->first)
                {
                    range_.first = rhs_iter_->first;
                }
                else
                {
                    range_.first = lhs_iter_->first;
                }

                if (rhs_iter_->second < lhs_iter_->second)
                {
                    range_.second = rhs_iter_->second;
                }
                else
                {
                    range_.second = lhs_iter_->second;
                }

                adjust (range_, *this, lhs_iter_, lhs_end_);
            }
        }
    }

    static string escape_char (const typename char_traits::index_type ch_)
    {
        string out_;

        switch (ch_)
        {
            case '\0':
                out_ += '\\';
                out_ += '0';
                break;
            case '\a':
                out_ += '\\';
                out_ += 'a';
                break;
            case '\b':
                out_ += '\\';
                out_ += 'b';
                break;
            case 27:
                out_ += '\\';
                out_ += 'x';
                out_ += '1';
                out_ += 'b';
                break;
            case '\f':
                out_ += '\\';
                out_ += 'f';
                break;
            case '\n':
                out_ += '\\';
                out_ += 'n';
                break;
            case '\r':
                out_ += '\\';
                out_ += 'r';
                break;
            case '\t':
                out_ += '\\';
                out_ += 't';
                break;
            case '\v':
                out_ += '\\';
                out_ += 'v';
                break;
            case '\\':
                out_ += '\\';
                out_ += '\\';
                break;
            case '"':
                out_ += '\\';
                out_ += '"';
                break;
            case '\'':
                out_ += '\\';
                out_ += '\'';
                break;
            default:
            {
                if (ch_ < 32 || ch_ > 126)
                {
                    std::basic_stringstream<char_type> ss_;

                    out_ += '\\';
                    out_ += 'x';
                    ss_ << std::hex <<
                        static_cast<std::size_t> (ch_);
                    out_ += ss_.str ();
                }
                else
                {
                    out_ += ch_;
                }

                break;
            }
        }

        return out_;
    }

private:
    void adjust (const range &range_, basic_string_token &token_,
        typename range_vector::iterator &iter_,
        typename range_vector::const_iterator &end_)
    {
        if (range_.first > iter_->first)
        {
            const index_type second_ = iter_->second;

            iter_->second = range_.first - 1;

            if (range_.second < second_)
            {
                range new_range_ (range_.second + 1, second_);

                iter_ = token_.insert (new_range_);
                end_ = token_._ranges.end ();
            }
        }
        else if (range_.second < iter_->second)
        {
            iter_->first = range_.second + 1;
        }
        else
        {
            iter_ = token_._ranges.erase (iter_);
            end_ = token_._ranges.end ();
        }
    }
};
}

#endif