label-table.h

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#ifndef TOC_LABEL_TABLE_H_INCLUDED
#define TOC_LABEL_TABLE_H_INCLUDED
/**********************************************************************/
/*
 * Copyright (c) 2014-2015, Jetro AS
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONRIBUTORS ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the EVE platform.
 */

/**
 * \file
 * @brief A part of TOC table compile-time generator
 *
 * @author DT, Jetro AS
 */ /******************************************************************/

#include "packed-sizeof.h"

/* Table entry; contains string just for the selected ID */
template <class Id>
struct CLabelTableEntry;

template <>
struct CLabelTableEntry<IntToType<-1> >
{};

/* Helper type, merges two types in one */
template <class T, class U>
struct MergeLabelTables
  : public T
  , public U
{};

/* Deduct return type for makeLabelTable */
template<class T>
struct label_table_t
{
  typedef typename std::conditional<
    /* Check for empty string. */
    (sizeof(CLabelTableEntry<T>) != 1),
    /* Include the entry if the duplicate is not found */
    MergeLabelTables<decltype(makeLabelTable(IntToType<T::value - 1>())), CLabelTableEntry<T> >,
    /* Skip the entry if the duplicate is found */
    decltype(makeLabelTable(IntToType<T::value - 1>()))
  >::type type;
};

/* Stop recursion */
template<>
struct label_table_t<IntToType<-1> >
{
  typedef CLabelTableEntry<IntToType<-1> > type;
};

/* Recursively make the table. */
template <class T>
constexpr typename label_table_t<T>::type makeLabelTable(T)
{
  return MergeLabelTables<
    decltype(makeLabelTable(IntToType<T::value - 1>())),
    CLabelTableEntry<T>
  >();
}

/* Stop recursion */
template <>
constexpr CLabelTableEntry<IntToType<-1> > makeLabelTable(IntToType<-1> t)
{
  return CLabelTableEntry<IntToType<-1> >();
}

#define TOC_DECLARE_LABEL(id, label)                          \
template <>                                                   \
struct CLabelTableEntry<IntToType<id> >                       \
{                                                             \
  const char content[sizeof(label)] = label;                  \
  static constexpr int raw_offset =                           \
    packed_sizeof(makeLabelTable(IntToType<id - 1>()));       \
  static constexpr int offset = (sizeof(content) == 1) ?      \
    -1 : raw_offset == 1 ? 0 : raw_offset;                    \
}

template<class Length>
struct CLabelPool
{
  const typename label_table_t<Length>::type impl = makeLabelTable(Length());
};

#endif