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Extract template function adjustSiblingSizes(), allowing instances to be shared

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between B+-trees using the same KeyT.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120170 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-11-26 06:54:17 +00:00
parent fd46797d0d
commit bf77baf19c
1 changed files with 86 additions and 75 deletions
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161
include/llvm/ADT/IntervalMap.h
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@ -294,6 +294,91 @@ public:
}
};
/// adjustSiblingSizes - Move elements between sibling nodes.
/// @param Node Array of pointers to sibling nodes.
/// @param Nodes Number of nodes.
/// @param CurSize Array of current node sizes, will be overwritten.
/// @param NewSize Array of desired node sizes.
template <typename NodeT>
void adjustSiblingSizes(NodeT *Node[], unsigned Nodes,
unsigned CurSize[], const unsigned NewSize[]) {
// Move elements right.
for (int n = Nodes - 1; n; --n) {
if (CurSize[n] == NewSize[n]) {
--Nodes;
continue;
}
for (int m = n - 1; m != -1; --m) {
int d = Node[n]->adjustFromLeftSib(CurSize[n], *Node[m], CurSize[m],
NewSize[n] - CurSize[n]);
CurSize[m] -= d;
CurSize[n] += d;
// Keep going if the current node was exhausted.
if (CurSize[n] >= NewSize[n])
break;
}
}
if (Nodes == 0)
return;
// Move elements left.
for (unsigned n = 0; n != Nodes - 1; ++n) {
if (CurSize[n] == NewSize[n])
continue;
for (unsigned m = n + 1; m != Nodes; ++m) {
int d = Node[m]->adjustFromLeftSib(CurSize[m], *Node[n], CurSize[n],
CurSize[n] - NewSize[n]);
CurSize[m] += d;
CurSize[n] -= d;
// Keep going if the current node was exhausted.
if (CurSize[n] >= NewSize[n])
break;
}
}
#ifndef NDEBUG
for (unsigned n = 0; n != Nodes; n++)
assert(CurSize[n] == NewSize[n] && "Insufficient element shuffle");
#endif
}
/// distribute - Compute a new distribution of node elements after an overflow
/// or underflow. Reserve space for a new element at Position, and compute the
/// node that will hold Position after redistributing node elements.
///
/// It is required that
///
/// Elements == sum(CurSize), and
/// Elements + Grow <= Nodes * Capacity.
///
/// NewSize[] will be filled in such that:
///
/// sum(NewSize) == Elements, and
/// NewSize[i] <= Capacity.
///
/// The returned index is the node where Position will go, so:
///
/// sum(NewSize[0..idx-1]) <= Position
/// sum(NewSize[0..idx]) >= Position
///
/// The last equality, sum(NewSize[0..idx]) == Position, can only happen when
/// Grow is set and NewSize[idx] == Capacity-1. The index points to the node
/// before the one holding the Position'th element where there is room for an
/// insertion.
///
/// @param Nodes The number of nodes.
/// @param Elements Total elements in all nodes.
/// @param Capacity The capacity of each node.
/// @param CurSize Array[Nodes] of current node sizes, or NULL.
/// @param NewSize Array[Nodes] to receive the new node sizes.
/// @param Position Insert position.
/// @param Grow Reserve space for a new element at Position.
/// @return (node, offset) for Position.
IdxPair distribute(unsigned Nodes, unsigned Elements, unsigned Capacity,
const unsigned *CurSize, unsigned NewSize[],
unsigned Position, bool Grow);
//===----------------------------------------------------------------------===//
//--- NodeSizer ---//
@ -1417,46 +1502,6 @@ const_iterator::treeFind(KeyT x) {
//--- iterator ----//
//===----------------------------------------------------------------------===//
namespace IntervalMapImpl {
/// distribute - Compute a new distribution of node elements after an overflow
/// or underflow. Reserve space for a new element at Position, and compute the
/// node that will hold Position after redistributing node elements.
///
/// It is required that
///
/// Elements == sum(CurSize), and
/// Elements + Grow <= Nodes * Capacity.
///
/// NewSize[] will be filled in such that:
///
/// sum(NewSize) == Elements, and
/// NewSize[i] <= Capacity.
///
/// The returned index is the node where Position will go, so:
///
/// sum(NewSize[0..idx-1]) <= Position
/// sum(NewSize[0..idx]) >= Position
///
/// The last equality, sum(NewSize[0..idx]) == Position, can only happen when
/// Grow is set and NewSize[idx] == Capacity-1. The index points to the node
/// before the one holding the Position'th element where there is room for an
/// insertion.
///
/// @param Nodes The number of nodes.
/// @param Elements Total elements in all nodes.
/// @param Capacity The capacity of each node.
/// @param CurSize Array[Nodes] of current node sizes, or NULL.
/// @param NewSize Array[Nodes] to receive the new node sizes.
/// @param Position Insert position.
/// @param Grow Reserve space for a new element at Position.
/// @return (node, offset) for Position.
IdxPair distribute(unsigned Nodes, unsigned Elements, unsigned Capacity,
const unsigned *CurSize, unsigned NewSize[],
unsigned Position, bool Grow);
}
template <typename KeyT, typename ValT, unsigned N, typename Traits>
class IntervalMap<KeyT, ValT, N, Traits>::iterator : public const_iterator {
friend class IntervalMap;
@ -1646,46 +1691,12 @@ iterator::overflow(unsigned Level) {
unsigned NewSize[4];
IdxPair NewOffset = distribute(Nodes, Elements, NodeT::Capacity,
CurSize, NewSize, Offset, true);
adjustSiblingSizes(Node, Nodes, CurSize, NewSize);
// Move current location to the leftmost node.
if (LeftSib)
P.moveLeft(Level);
// Move elements right.
for (int n = Nodes - 1; n; --n) {
if (CurSize[n] == NewSize[n])
continue;
for (int m = n - 1; m != -1; --m) {
int d = Node[n]->adjustFromLeftSib(CurSize[n], *Node[m], CurSize[m],
NewSize[n] - CurSize[n]);
CurSize[m] -= d;
CurSize[n] += d;
// Keep going if the current node was exhausted.
if (CurSize[n] >= NewSize[n])
break;
}
}
// Move elements left.
for (unsigned n = 0; n != Nodes - 1; ++n) {
if (CurSize[n] == NewSize[n])
continue;
for (unsigned m = n + 1; m != Nodes; ++m) {
int d = Node[m]->adjustFromLeftSib(CurSize[m], *Node[n], CurSize[n],
CurSize[n] - NewSize[n]);
CurSize[m] += d;
CurSize[n] -= d;
// Keep going if the current node was exhausted.
if (CurSize[n] >= NewSize[n])
break;
}
}
#ifndef NDEBUG
for (unsigned n = 0; n != Nodes; n++)
assert(CurSize[n] == NewSize[n] && "Insufficient element shuffle");
#endif
// Elements have been rearranged, now update node sizes and stops.
bool SplitRoot = false;
unsigned Pos = 0;