/*=============================================================================
    Copyright (c) 2001-2011 Joel de Guzman

    Distributed under the Boost Software License, Version 1.0. (See accompanying
    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
==============================================================================*/
#if !defined(BOOST_SPIRIT_RANGE_RUN_MAY_16_2006_0807_PM)
#define BOOST_SPIRIT_RANGE_RUN_MAY_16_2006_0807_PM

#if defined(_MSC_VER)
#pragma once
#endif

#include <boost/spirit/home/support/char_set/range_functions.hpp>
#include <boost/assert.hpp>
#include <algorithm>

namespace boost {
namespace spirit {
namespace support {
namespace detail {
template <typename Run, typename Iterator, typename Range>
inline bool
try_merge(Run& run, Iterator iter, Range const& range)
{
    // if *iter intersects with, or is adjacent to, 'range'...
    if (can_merge(*iter, range))
    {
        // merge range and *iter
        merge(*iter, range);

        // collapse all subsequent ranges that can merge with *iter:
        Iterator i = iter+1;

        // 1. skip subsequent ranges completely included in *iter
        while (i != run.end() && i->last <= iter->last)
        {
            ++i;
        }

        // 2. collapse next range if adjacent or overlapping with *iter
        if (i != run.end() && i->first-1 <= iter->last)
        {
            iter->last = i->last;
            ++i;
        }

        // erase all ranges that were collapsed
        run.erase(iter+1, i);
        return true;
    }

    return false;
}

template <typename Char>
inline bool
range_run<Char>::test(Char val) const
{
    if (run.empty())
    {
        return false;
    }

    // search the ranges for one that potentially includes val
    typename storage_type::const_iterator iter =
        std::upper_bound(
            run.begin(), run.end(), val,
            range_compare<range_type>()
        );

    // return true if *(iter-1) includes val
    return iter != run.begin() && includes(*(--iter), val);
}

template <typename Char>
inline void
range_run<Char>::swap(range_run& other)
{
    run.swap(other.run);
}

template <typename Char>
void
range_run<Char>::set(range_type const& range)
{
    BOOST_ASSERT(is_valid(range));

    if (run.empty())
    {
        // the vector is empty, insert 'range'
        run.push_back(range);
        return;
    }

    // search the ranges for one that potentially includes 'range'
    typename storage_type::iterator iter =
        std::upper_bound(
            run.begin(), run.end(), range,
            range_compare<range_type>()
        );

    if (iter != run.begin())
    {
        // if *(iter-1) includes 'range', return early
        if (includes(*(iter-1), range))
        {
            return;
        }

        // if *(iter-1) can merge with 'range', merge them and return
        if (try_merge(run, iter-1, range))
        {
            return;
        }
    }

    // if *iter can merge with with 'range', merge them
    if (iter == run.end() || !try_merge(run, iter, range))
    {
        // no overlap, insert 'range'
        run.insert(iter, range);
    }
}

template <typename Char>
void
range_run<Char>::clear(range_type const& range)
{
    BOOST_ASSERT(is_valid(range));

    if (!run.empty())
    {
        // search the ranges for one that potentially includes 'range'
        typename storage_type::iterator iter =
            std::upper_bound(
                run.begin(), run.end(), range,
                range_compare<range_type>()
            );

        // 'range' starts with or after another range:
        if (iter != run.begin())
        {
            typename storage_type::iterator const left_iter = iter-1;

            // 'range' starts after '*left_iter':
            if (left_iter->first < range.first)
            {
                // if 'range' is completely included inside '*left_iter':
                // need to break it apart into two ranges (punch a hole),
                if (left_iter->last > range.last)
                {
                    Char save_last = left_iter->last;
                    left_iter->last = range.first-1;
                    run.insert(iter, range_type(range.last+1, save_last));
                    return;
                }

                // if 'range' contains 'left_iter->last':
                // truncate '*left_iter' (clip its right)
                else if (left_iter->last >= range.first)
                {
                    left_iter->last = range.first-1;
                }
            }

            // 'range' has the same left bound as '*left_iter': it
            // must be removed or truncated by the code below
            else
            {
                iter = left_iter;
            }
        }

        // remove or truncate subsequent ranges that overlap with 'range':
        typename storage_type::iterator i = iter;

        // 1. skip subsequent ranges completely included in 'range'
        while (i != run.end() && i->last <= range.last)
        {
            ++i;
        }

        // 2. clip left of next range if overlapping with 'range'
        if (i != run.end() && i->first <= range.last)
        {
            i->first = range.last+1;
        }

        // erase all ranges that 'range' contained
        run.erase(iter, i);
    }
}

template <typename Char>
inline void
range_run<Char>::clear()
{
    run.clear();
}
}
}
}
}

#endif
