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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.trino.operator.window;
import io.trino.operator.PagesIndex;
import io.trino.sql.tree.FrameBound;
import io.trino.sql.tree.WindowFrame;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static io.trino.sql.tree.FrameBound.Type.FOLLOWING;
import static io.trino.sql.tree.FrameBound.Type.PRECEDING;
import static io.trino.sql.tree.FrameBound.Type.UNBOUNDED_FOLLOWING;
import static io.trino.sql.tree.FrameBound.Type.UNBOUNDED_PRECEDING;
import static java.lang.Math.toIntExact;
public class RowsFraming
implements Framing
{
private final FrameInfo frameInfo;
private final PagesIndex pagesIndex;
private final int partitionStart;
private final int partitionEnd;
public RowsFraming(FrameInfo frameInfo, int partitionStart, int partitionEnd, PagesIndex pagesIndex)
{
checkArgument(frameInfo.getType() == WindowFrame.Type.ROWS, "Frame must be of type ROWS, actual: %s", frameInfo.getType());
this.frameInfo = frameInfo;
this.pagesIndex = pagesIndex;
this.partitionStart = partitionStart;
this.partitionEnd = partitionEnd;
}
@Override
public Range getRange(int currentPosition, int currentGroup, int peerGroupStart, int peerGroupEnd)
{
int rowPosition = currentPosition - partitionStart;
int endPosition = partitionEnd - partitionStart - 1;
// handle empty frame
if (emptyFrame(frameInfo, rowPosition, endPosition)) {
return new Range(-1, -1);
}
int frameStart;
int frameEnd;
// frame start
if (frameInfo.getStartType() == UNBOUNDED_PRECEDING) {
frameStart = 0;
}
else if (frameInfo.getStartType() == PRECEDING) {
frameStart = preceding(rowPosition, getValue(frameInfo.getStartChannel(), currentPosition));
}
else if (frameInfo.getStartType() == FOLLOWING) {
frameStart = following(rowPosition, endPosition, getValue(frameInfo.getStartChannel(), currentPosition));
}
else {
frameStart = rowPosition;
}
// frame end
if (frameInfo.getEndType() == UNBOUNDED_FOLLOWING) {
frameEnd = endPosition;
}
else if (frameInfo.getEndType() == PRECEDING) {
frameEnd = preceding(rowPosition, getValue(frameInfo.getEndChannel(), currentPosition));
}
else if (frameInfo.getEndType() == FOLLOWING) {
frameEnd = following(rowPosition, endPosition, getValue(frameInfo.getEndChannel(), currentPosition));
}
else {
frameEnd = rowPosition;
}
return new Range(frameStart, frameEnd);
}
private boolean emptyFrame(FrameInfo frameInfo, int rowPosition, int endPosition)
{
FrameBound.Type startType = frameInfo.getStartType();
FrameBound.Type endType = frameInfo.getEndType();
int positions = endPosition - rowPosition;
if ((startType == UNBOUNDED_PRECEDING) && (endType == PRECEDING)) {
return getValue(frameInfo.getEndChannel(), 0) > rowPosition;
}
if ((startType == FOLLOWING) && (endType == UNBOUNDED_FOLLOWING)) {
return getValue(frameInfo.getStartChannel(), 0) > positions;
}
if (startType != endType) {
return false;
}
FrameBound.Type type = frameInfo.getStartType();
if ((type != PRECEDING) && (type != FOLLOWING)) {
return false;
}
long start = getValue(frameInfo.getStartChannel(), 0);
long end = getValue(frameInfo.getEndChannel(), 0);
if (type == PRECEDING) {
return (start < end) || ((start > rowPosition) && (end > rowPosition));
}
return (start > end) || (start > positions);
}
private static int preceding(int rowPosition, long value)
{
if (value > rowPosition) {
return 0;
}
return toIntExact(rowPosition - value);
}
private static int following(int rowPosition, int endPosition, long value)
{
if (value > (endPosition - rowPosition)) {
return endPosition;
}
return toIntExact(rowPosition + value);
}
private long getValue(int channel, int currentPosition)
{
checkState(!pagesIndex.isNull(channel, currentPosition), "Window frame offset must not be null");
long value = pagesIndex.getLong(channel, currentPosition);
checkState(value >= 0, "Window frame offset must not be negative");
return value;
}
}
