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// Scintilla source code edit control
/** @file Partitioning.h
** Data structure used to partition an interval. Used for holding line start/end positions.
**/
// Copyright 1998-2007 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.
#ifndef PARTITIONING_H
#define PARTITIONING_H
/// A split vector of integers with a method for adding a value to all elements
/// in a range.
/// Used by the Partitioning class.
class SplitVectorWithRangeAdd : public SplitVector<int> {
public:
SplitVectorWithRangeAdd(int growSize_) {
SetGrowSize(growSize_);
ReAllocate(growSize_);
}
~SplitVectorWithRangeAdd() {
}
void RangeAddDelta(int start, int end, int delta) {
// end is 1 past end, so end-start is number of elements to change
int i = 0;
int rangeLength = end - start;
int range1Length = rangeLength;
int part1Left = part1Length - start;
if (range1Length > part1Left)
range1Length = part1Left;
while (i < range1Length) {
body[start++] += delta;
i++;
}
start += gapLength;
while (i < rangeLength) {
body[start++] += delta;
i++;
}
}
};
/// Divide an interval into multiple partitions.
/// Useful for breaking a document down into sections such as lines.
class Partitioning {
private:
// To avoid calculating all the partition positions whenever any text is inserted
// there may be a step somewhere in the list.
int stepPartition;
int stepLength;
SplitVectorWithRangeAdd *body;
// Move step forward
void ApplyStep(int partitionUpTo) {
if (stepLength != 0) {
body->RangeAddDelta(stepPartition+1, partitionUpTo + 1, stepLength);
}
stepPartition = partitionUpTo;
if (stepPartition >= body->Length()-1) {
stepPartition = body->Length()-1;
stepLength = 0;
}
}
// Move step backward
void BackStep(int partitionDownTo) {
if (stepLength != 0) {
body->RangeAddDelta(partitionDownTo+1, stepPartition+1, -stepLength);
}
stepPartition = partitionDownTo;
}
void Allocate(int growSize) {
body = new SplitVectorWithRangeAdd(growSize);
stepPartition = 0;
stepLength = 0;
body->Insert(0, 0); // This value stays 0 for ever
body->Insert(1, 0); // This is the end of the first partition and will be the start of the second
}
public:
Partitioning(int growSize) {
Allocate(growSize);
}
~Partitioning() {
delete body;
body = 0;
}
int Partitions() const {
return body->Length()-1;
}
void InsertPartition(int partition, int pos) {
if (stepPartition < partition) {
ApplyStep(partition);
}
body->Insert(partition, pos);
stepPartition++;
}
void SetPartitionStartPosition(int partition, int pos) {
ApplyStep(partition+1);
if ((partition < 0) || (partition > body->Length())) {
return;
}
body->SetValueAt(partition, pos);
}
void InsertText(int partitionInsert, int delta) {
// Point all the partitions after the insertion point further along in the buffer
if (stepLength != 0) {
if (partitionInsert >= stepPartition) {
// Fill in up to the new insertion point
ApplyStep(partitionInsert);
stepLength += delta;
} else if (partitionInsert >= (stepPartition - body->Length() / 10)) {
// Close to step but before so move step back
BackStep(partitionInsert);
stepLength += delta;
} else {
ApplyStep(body->Length()-1);
stepPartition = partitionInsert;
stepLength = delta;
}
} else {
stepPartition = partitionInsert;
stepLength = delta;
}
}
void RemovePartition(int partition) {
if (partition > stepPartition) {
ApplyStep(partition);
stepPartition--;
} else {
stepPartition--;
}
body->Delete(partition);
}
int PositionFromPartition(int partition) const {
PLATFORM_ASSERT(partition >= 0);
PLATFORM_ASSERT(partition < body->Length());
if ((partition < 0) || (partition >= body->Length())) {
return 0;
}
int pos = body->ValueAt(partition);
if (partition > stepPartition)
pos += stepLength;
return pos;
}
int PartitionFromPosition(int pos) const {
if (body->Length() <= 1)
return 0;
if (pos >= (PositionFromPartition(body->Length()-1)))
return body->Length() - 1 - 1;
int lower = 0;
int upper = body->Length()-1;
do {
int middle = (upper + lower + 1) / 2; // Round high
int posMiddle = body->ValueAt(middle);
if (middle > stepPartition)
posMiddle += stepLength;
if (pos < posMiddle) {
upper = middle - 1;
} else {
lower = middle;
}
} while (lower < upper);
return lower;
}
void DeleteAll() {
int growSize = body->GetGrowSize();
delete body;
Allocate(growSize);
}
};
#endif
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