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//===- lib/Support/IntervalMap.cpp - A sorted interval map ----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the few non-templated functions in IntervalMap.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/IntervalMap.h"
#include <cassert>
namespace llvm {
namespace IntervalMapImpl {
void Path::replaceRoot(void *Root, unsigned Size, IdxPair Offsets) {
assert(!path.empty() && "Can't replace missing root");
path.front() = Entry(Root, Size, Offsets.first);
path.insert(path.begin() + 1, Entry(subtree(0), Offsets.second));
}
NodeRef Path::getLeftSibling(unsigned Level) const {
// The root has no siblings.
if (Level == 0)
return NodeRef();
// Go up the tree until we can go left.
unsigned l = Level - 1;
while (l && path[l].offset == 0)
--l;
// We can't go left.
if (path[l].offset == 0)
return NodeRef();
// NR is the subtree containing our left sibling.
NodeRef NR = path[l].subtree(path[l].offset - 1);
// Keep right all the way down.
for (++l; l != Level; ++l)
NR = NR.subtree(NR.size() - 1);
return NR;
}
void Path::moveLeft(unsigned Level) {
assert(Level != 0 && "Cannot move the root node");
// Go up the tree until we can go left.
unsigned l = 0;
if (valid()) {
l = Level - 1;
while (path[l].offset == 0) {
assert(l != 0 && "Cannot move beyond begin()");
--l;
}
} else if (height() < Level)
// end() may have created a height=0 path.
path.resize(Level + 1, Entry(nullptr, 0, 0));
// NR is the subtree containing our left sibling.
--path[l].offset;
NodeRef NR = subtree(l);
// Get the rightmost node in the subtree.
for (++l; l != Level; ++l) {
path[l] = Entry(NR, NR.size() - 1);
NR = NR.subtree(NR.size() - 1);
}
path[l] = Entry(NR, NR.size() - 1);
}
NodeRef Path::getRightSibling(unsigned Level) const {
// The root has no siblings.
if (Level == 0)
return NodeRef();
// Go up the tree until we can go right.
unsigned l = Level - 1;
while (l && atLastEntry(l))
--l;
// We can't go right.
if (atLastEntry(l))
return NodeRef();
// NR is the subtree containing our right sibling.
NodeRef NR = path[l].subtree(path[l].offset + 1);
// Keep left all the way down.
for (++l; l != Level; ++l)
NR = NR.subtree(0);
return NR;
}
void Path::moveRight(unsigned Level) {
assert(Level != 0 && "Cannot move the root node");
// Go up the tree until we can go right.
unsigned l = Level - 1;
while (l && atLastEntry(l))
--l;
// NR is the subtree containing our right sibling. If we hit end(), we have
// offset(0) == node(0).size().
if (++path[l].offset == path[l].size)
return;
NodeRef NR = subtree(l);
for (++l; l != Level; ++l) {
path[l] = Entry(NR, 0);
NR = NR.subtree(0);
}
path[l] = Entry(NR, 0);
}
IdxPair distribute(unsigned Nodes, unsigned Elements, unsigned Capacity,
const unsigned *CurSize, unsigned NewSize[],
unsigned Position, bool Grow) {
assert(Elements + Grow <= Nodes * Capacity && "Not enough room for elements");
assert(Position <= Elements && "Invalid position");
if (!Nodes)
return IdxPair();
// Trivial algorithm: left-leaning even distribution.
const unsigned PerNode = (Elements + Grow) / Nodes;
const unsigned Extra = (Elements + Grow) % Nodes;
IdxPair PosPair = IdxPair(Nodes, 0);
unsigned Sum = 0;
for (unsigned n = 0; n != Nodes; ++n) {
Sum += NewSize[n] = PerNode + (n < Extra);
if (PosPair.first == Nodes && Sum > Position)
PosPair = IdxPair(n, Position - (Sum - NewSize[n]));
}
assert(Sum == Elements + Grow && "Bad distribution sum");
// Subtract the Grow element that was added.
if (Grow) {
assert(PosPair.first < Nodes && "Bad algebra");
assert(NewSize[PosPair.first] && "Too few elements to need Grow");
--NewSize[PosPair.first];
}
#ifndef NDEBUG
Sum = 0;
for (unsigned n = 0; n != Nodes; ++n) {
assert(NewSize[n] <= Capacity && "Overallocated node");
Sum += NewSize[n];
}
assert(Sum == Elements && "Bad distribution sum");
#endif
return PosPair;
}
} // namespace IntervalMapImpl
} // namespace llvm
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