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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2025, Ben Burton *
* For further details contact Ben Burton (bab@debian.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. *
* *
* As an exception, when this program is distributed through (i) the *
* App Store by Apple Inc.; (ii) the Mac App Store by Apple Inc.; or *
* (iii) Google Play by Google Inc., then that store may impose any *
* digital rights management, device limits and/or redistribution *
* restrictions that are required by its terms of service. *
* *
* 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, see <https://www.gnu.org/licenses/>. *
* *
**************************************************************************/
#include <vector>
#include "surface/normalsurfaces.h"
#include "surface/surfacefilter.h"
#include "triangulation/dim3.h"
namespace regina {
namespace {
inline constexpr NormalCoords transformCoords(NormalCoords src,
NormalTransform t) {
switch (t) {
case NormalTransform::ConvertReducedToStandard:
switch (src) {
case NormalCoords::Quad: return NormalCoords::Standard;
case NormalCoords::QuadOct:
return NormalCoords::AlmostNormal;
default:
throw FailedPrecondition("Reduced-to-standard "
"conversion is only available from coordinate "
"systems NormalCoords::Quad and "
"NormalCoords::QuadOct");
}
case NormalTransform::ConvertStandardToReduced:
switch (src) {
case NormalCoords::Standard: return NormalCoords::Quad;
case NormalCoords::AlmostNormal:
return NormalCoords::QuadOct;
default:
throw FailedPrecondition("Standard-to-reduced "
"conversion is only available from coordinate "
"systems NormalCoords::Standard and "
"NormalCoords::AlmostNormal");
}
default:
return src;
}
}
inline Flags<NormalList> transformList(Flags<NormalList> src,
NormalTransform t) {
switch (t) {
case NormalTransform::ConvertReducedToStandard:
case NormalTransform::ConvertStandardToReduced:
if (src != (NormalList::EmbeddedOnly | NormalList::Vertex))
throw FailedPrecondition("Conversion between "
"standard and reduced coordinate systems requires "
"the source list to contain exactly all "
"embedded vertex surfaces");
return src;
case NormalTransform::FilterCompatible:
case NormalTransform::FilterDisjoint:
case NormalTransform::FilterIncompressible:
if (! src.has(NormalList::EmbeddedOnly))
throw FailedPrecondition("This filter requires "
"the input list to contain only embedded surfaces");
return NormalList::Custom | NormalList::EmbeddedOnly;
default:
return NormalList::Custom;
}
}
inline Flags<NormalAlg> transformAlg(Flags<NormalAlg> src,
NormalTransform t) {
switch (t) {
case NormalTransform::ConvertReducedToStandard:
return src | NormalAlg::VertexViaReduced;
default:
return NormalAlg::Custom;
}
}
}
NormalSurfaces::NormalSurfaces(const NormalSurfaces& src,
NormalTransform transform) :
NormalSurfaces(transformCoords(src.coords_, transform),
transformList(src.which_, transform),
transformAlg(src.algorithm_, transform), src.triangulation_) {
switch (transform) {
case NormalTransform::ConvertReducedToStandard:
if (src.triangulation_->isIdeal() ||
! src.triangulation_->isValid())
throw FailedPrecondition("Conversion from reduced to "
"standard coordinate systems requires a "
"valid, non-ideal triangulation");
buildStandardFromReduced(src.surfaces_);
break;
case NormalTransform::ConvertStandardToReduced:
if (src.triangulation_->isIdeal() ||
! src.triangulation_->isValid())
throw FailedPrecondition("Conversion from standard to "
"reduced coordinate systems requires a "
"valid, non-ideal triangulation");
buildReducedFromStandard(src.surfaces_);
break;
case NormalTransform::FilterCompatible:
for (const auto& a : src.surfaces_)
for (const auto& b : src.surfaces_)
if (&a != &b && a.locallyCompatible(b)) {
surfaces_.push_back(a);
break;
}
break;
case NormalTransform::FilterDisjoint:
{
std::vector<const NormalSurface*> interesting;
for (const NormalSurface& s : src.surfaces_)
if ((! s.isEmpty()) && s.isCompact() && s.isConnected())
interesting.push_back(&s);
for (const auto* a : interesting)
for (const auto* b : interesting)
if (a != b && a->disjoint(*b)) {
surfaces_.push_back(*a);
break;
}
}
break;
case NormalTransform::FilterIncompressible:
for (const NormalSurface& s : src.surfaces_) {
if (s.isVertexLinking() || s.isThinEdgeLink().first)
continue;
// If we have a one-sided surface, don't worry about taking the
// two-sided double cover. If the complement of the one-sided
// surface has a compressing disc, then the complement of the
// double cover has the same compressing disc, and this surface
// can happily be tossed away.
if (! s.cutAlong().hasSimpleCompressingDisc())
surfaces_.push_back(s);
}
break;
default:
throw FailedPrecondition(
"The transformation type was not recognised");
}
}
NormalSurfaces::NormalSurfaces(const NormalSurfaces& src,
const SurfaceFilter& filter) :
NormalSurfaces(
src.coords_,
(src.which_ &
(NormalList::EmbeddedOnly | NormalList::ImmersedSingular)) |
NormalList::Custom,
src.algorithm_ | NormalAlg::Custom,
src.triangulation_) {
for (const NormalSurface& s : src.surfaces_)
if (filter.accept(s))
surfaces_.push_back(s);
}
} // namespace regina
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