/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.index;
import org.h2.api.ErrorCode;
import org.h2.command.query.AllColumnsForPlan;
import org.h2.engine.SessionLocal;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.IndexColumn;
import org.h2.table.RangeTable;
import org.h2.table.TableFilter;
import org.h2.value.Value;
import org.h2.value.ValueBigint;
/**
* An index for the SYSTEM_RANGE table.
* This index can only scan through all rows, search is not supported.
*/
public class RangeIndex extends VirtualTableIndex {
private final RangeTable rangeTable;
public RangeIndex(RangeTable table, IndexColumn[] columns) {
super(table, "RANGE_INDEX", columns);
this.rangeTable = table;
}
@Override
public Cursor find(SessionLocal session, SearchRow first, SearchRow last) {
long min = rangeTable.getMin(session);
long max = rangeTable.getMax(session);
long step = rangeTable.getStep(session);
if (step == 0L) {
throw DbException.get(ErrorCode.STEP_SIZE_MUST_NOT_BE_ZERO);
}
if (first != null) {
try {
long v = first.getValue(0).getLong();
if (step > 0) {
if (v > min) {
min += (v - min + step - 1) / step * step;
}
} else if (v > max) {
max = v;
}
} catch (DbException e) {
// error when converting the value - ignore
}
}
if (last != null) {
try {
long v = last.getValue(0).getLong();
if (step > 0) {
if (v < max) {
max = v;
}
} else if (v < min) {
min -= (min - v - step - 1) / step * step;
}
} catch (DbException e) {
// error when converting the value - ignore
}
}
return new RangeCursor(min, max, step);
}
@Override
public double getCost(SessionLocal session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
AllColumnsForPlan allColumnsSet) {
return 1d;
}
@Override
public String getCreateSQL() {
return null;
}
@Override
public boolean canGetFirstOrLast() {
return true;
}
@Override
public Cursor findFirstOrLast(SessionLocal session, boolean first) {
long min = rangeTable.getMin(session);
long max = rangeTable.getMax(session);
long step = rangeTable.getStep(session);
if (step == 0L) {
throw DbException.get(ErrorCode.STEP_SIZE_MUST_NOT_BE_ZERO);
}
return new SingleRowCursor((step > 0 ? min <= max : min >= max)
? Row.get(new Value[]{ ValueBigint.get(first ^ min >= max ? min : max) }, 1) : null);
}
@Override
public String getPlanSQL() {
return "range index";
}
}