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/** \file tier_operation.cc */
// Copyright (C) 2010 Daniel Burrows
//
// 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; see the file COPYING. If not, write to
// the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
#include "tier_operation.h"
tier tier_operation::levelwise_maximum(const tier &t1, const tier &t2)
{
const int out_structural_level =
std::max<int>(t1.get_structural_level(),
t2.get_structural_level());
std::vector<int> out_user_levels;
out_user_levels.reserve(std::max<std::size_t>(t1.get_num_user_levels(),
t2.get_num_user_levels()));
tier::user_level_iterator
it1 = t1.user_levels_begin(),
it2 = t2.user_levels_begin();
const tier::user_level_iterator
end1 = t1.user_levels_end(),
end2 = t2.user_levels_end();
while(it1 != end1 && it2 != end2)
{
out_user_levels.push_back(std::max<int>(*it1, *it2));
++it1;
++it2;
}
if(it1 != end1)
out_user_levels.insert(out_user_levels.end(),
it1, end1);
else if(it2 != end2)
out_user_levels.insert(out_user_levels.end(),
it2, end2);
return tier(out_structural_level,
out_user_levels.begin(),
out_user_levels.end());
}
inline int tier_operation::safe_add_levels(int l1, int l2)
{
if(l1 < 0 && l2 < 0)
throw NegativeTierAdditionException();
// Check for overflow.
//
// If one level is nonnegative, we can only overflow if both are
// strictly positive.
if(l1 > 0 && l2 > 0 &&
l1 > (INT_MAX - l2))
throw TierTooBigException();
return l1 + l2;
}
tier tier_operation::levelwise_add(const tier &t1, const tier &t2)
{
int out_structural_level =
safe_add_levels(t1.get_structural_level(), t2.get_structural_level());
std::vector<int> out_user_levels;
tier::user_level_iterator
it1 = t1.user_levels_begin(),
it2 = t2.user_levels_begin();
const tier::user_level_iterator
end1 = t1.user_levels_end(),
end2 = t2.user_levels_end();
while(it1 != end1 && it2 != end2)
{
out_user_levels.push_back(safe_add_levels(*it1, *it2));
++it1;
++it2;
}
if(it1 != end1)
out_user_levels.insert(out_user_levels.end(),
it1, end1);
else if(it2 != end2)
out_user_levels.insert(out_user_levels.end(),
it2, end2);
return tier(out_structural_level,
out_user_levels.begin(),
out_user_levels.end());
}
tier_operation tier_operation::operator+(const tier_operation &other) const
{
return tier_operation(levelwise_maximum(increase_levels,
other.increase_levels),
levelwise_add(add_levels,
other.add_levels));
}
tier tier_operation::apply(const tier &t) const
{
// Note that we construct an unnecessary intermediate tier here;
// that could be avoided by having the levelwise routines operate on
// int vectors instead of tiers.
const tier increased = levelwise_maximum(t, increase_levels);
return levelwise_add(t, add_levels);
}
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