chan_mapping.h

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/*
 * Copyright (C) 2009-2011 David Robillard <d@drobilla.net>
 * Copyright (C) 2016 Robin Gareus <robin@gareus.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#pragma once
 
#include <map>
#include <cassert>
#include <ostream>
#include <utility>
 
#include "pbd/stack_allocator.h"
#include "pbd/xml++.h"
 
#include "ardour/data_type.h"
#include "ardour/chan_count.h"
 
namespace ARDOUR {
 
class LIBARDOUR_API ChanMapping {
public:
        ChanMapping() {}
        ChanMapping(ARDOUR::ChanCount identity);
        ChanMapping(const ChanMapping&);
        ChanMapping(const XMLNode& node);
 
        ChanMapping operator=(const ChanMapping&);
 
        uint32_t get(DataType t, uint32_t from, bool* valid) const;
 
        uint32_t get_src(DataType type, uint32_t to, bool* valid) const;
 
        uint32_t get (DataType type, uint32_t from) const { return get (type, from, NULL); }
 
        void     set (DataType type, uint32_t from, uint32_t to);
 
        void     offset_from (DataType t, int32_t delta);
        void     offset_to (DataType t, int32_t delta);
 
        void     unset(DataType type, uint32_t from);
 
        bool     is_identity (ARDOUR::ChanCount offset = ARDOUR::ChanCount()) const;
 
        bool     is_monotonic () const;
 
        uint32_t n_total () const;
 
        ChanCount count () const;
 
        XMLNode* state(const std::string& name) const;
 
        bool     is_subset (const ChanMapping& superset) const;
 
#if defined(_MSC_VER) /* && (_MSC_VER < 1900)
                           * Regarding the note (below) it was initially
                           * thought that this got fixed in VS2015 - but
                           * in fact it's still faulty (JE - Feb 2021).
                           * 2024-09-03 update: Faulty compile up to
                           * VS2022 17.4. From there it compiles but does
                           * not link with the exception of the arm64
                           * platform. This quirk is actually a bug that
                           * Microsoft seems to have failed to
                           * acknowledge as such for years judging from
                           * web search results about MSVC's std::map,
                                           * and have not even fixed correctly when they
                                           * tried.
                           */
        /* Use the older (heap based) mapping for early versions of MSVC.
         * In fact it might be safer to use this for all MSVC builds. It
         * was thought that this was related to issues with
         * boost::aligned_storage, but actually it seems to be that there
         * are bugs in the std::map implementation of MSVC that are being
         * triggered, messing with the copy constructor of
         * PBD::StackAllocator.
         */
        typedef std::map<uint32_t, uint32_t>    TypeMapping;
        typedef std::map<DataType, TypeMapping> Mappings;
#else
        typedef std::map<uint32_t, uint32_t, std::less<uint32_t>, PBD::StackAllocator<std::pair<const uint32_t, uint32_t>, 16> > TypeMapping;
        typedef std::map<DataType, TypeMapping, std::less<DataType>, PBD::StackAllocator<std::pair<const DataType, TypeMapping>, 2> > Mappings;
#endif
 
        Mappings        mappings()       { return _mappings; }
        const Mappings& mappings() const { return _mappings; }
 
        bool operator==(const ChanMapping& other) const {
                return (_mappings == other._mappings);
        }
 
        bool operator!=(const ChanMapping& other) const {
                return ! (*this == other);
        }
 
private:
        Mappings _mappings;
};
 
} // namespace ARDOUR
 
std::ostream& operator<<(std::ostream& o, const ARDOUR::ChanMapping& m);