one.util.streamex.PairSpliterator Maven / Gradle / Ivy
/*
* Copyright 2015, 2016 Tagir Valeev
*
* 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 one.util.streamex;
import java.util.Spliterator;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.DoubleBinaryOperator;
import java.util.function.DoubleConsumer;
import java.util.function.DoubleUnaryOperator;
import java.util.function.Function;
import java.util.function.IntBinaryOperator;
import java.util.function.IntConsumer;
import java.util.function.IntUnaryOperator;
import java.util.function.LongBinaryOperator;
import java.util.function.LongConsumer;
import java.util.function.LongUnaryOperator;
import static one.util.streamex.StreamExInternals.*;
/**
* @author Tagir Valeev
*/
/* package */abstract class PairSpliterator, R, SS extends PairSpliterator>
extends CloneableSpliterator {
static final int MODE_PAIRS = 0;
static final int MODE_MAP_FIRST = 1;
static final int MODE_MAP_LAST = 2;
static final int MODE_MAP_FIRST_OR_ELSE = 3;
static final int MODE_MAP_LAST_OR_ELSE = 4;
static final Sink EMPTY = new Sink<>(null);
// Common lock for all the derived spliterators
final Object lock = new Object();
final int mode;
S source;
@SuppressWarnings("unchecked")
Sink left = (Sink) EMPTY;
@SuppressWarnings("unchecked")
Sink right = (Sink) EMPTY;
static final class Sink {
Sink other;
private T payload = none();
private final Object lock;
Sink(Object lock) {
this.lock = lock;
}
boolean push(T payload, BiConsumer fn, boolean isLeft) {
if (lock == null)
return false;
T otherPayload;
synchronized (lock) {
Sink that = other;
if (that == null)
return false;
otherPayload = that.payload;
if (otherPayload == NONE) {
this.payload = payload;
return false;
}
other = null;
that.clear();
}
if (isLeft)
fn.accept(payload, otherPayload);
else
fn.accept(otherPayload, payload);
return true;
}
boolean connect(Sink right, BiConsumer fn) {
if (lock == null)
return false;
T a, b;
synchronized (lock) {
Sink leftLeft = this.other;
Sink rightRight = right.other;
if (leftLeft == null || rightRight == null) {
if (rightRight != null)
rightRight.clear();
if (leftLeft != null)
leftLeft.clear();
return false;
}
rightRight.other = leftLeft;
leftLeft.other = rightRight;
if (leftLeft.payload == NONE || rightRight.payload == NONE)
return false;
a = leftLeft.payload;
b = rightRight.payload;
leftLeft.clear();
rightRight.clear();
}
fn.accept(a, b);
return true;
}
void clear() {
other = null;
payload = none();
}
}
PairSpliterator(S source, int mode, T headTail) {
this.source = source;
this.mode = mode;
if(mode != MODE_PAIRS) {
Sink sink = new Sink<>(this.lock);
Sink other = new Sink<>(this.lock);
sink.other = other;
other.other = sink;
other.push(headTail, null, true);
if(mode == MODE_MAP_FIRST || mode == MODE_MAP_FIRST_OR_ELSE)
this.left = sink;
else
this.right = sink;
}
}
@Override
public long estimateSize() {
long size = source.estimateSize();
if (size == Long.MAX_VALUE || size == 0)
return size;
return size - 1;
}
@Override
public int characteristics() {
return source.characteristics()
& ((left == EMPTY && right == EMPTY ? SIZED : 0) | CONCURRENT | IMMUTABLE | ORDERED);
}
@SuppressWarnings("unchecked")
@Override
public SS trySplit() {
S prefixSource = (S) source.trySplit();
if (prefixSource == null)
return null;
SS clone = doClone();
Sink left = new Sink<>(lock);
Sink right = new Sink<>(lock);
clone.source = prefixSource;
clone.right = right.other = left;
this.left = left.other = right;
return clone;
}
void finish(BiConsumer fn, T cur) {
Sink r = right, l = left;
right = left = null;
if (l != null) {
l.connect(r, fn);
} else if (r != null) {
r.push(cur, fn, true);
}
}
static class PSOfRef extends PairSpliterator, R, PSOfRef> implements
Consumer, TailSpliterator {
private static final Object HEAD_TAIL = new Object();
private final BiFunction mapper;
private T cur;
PSOfRef(BiFunction mapper, Spliterator source) {
super(source, MODE_PAIRS, null);
this.mapper = mapper;
}
// Must be called only if T == R
@SuppressWarnings("unchecked")
PSOfRef(Function mapper, Spliterator source, boolean first) {
super(source, first ? MODE_MAP_FIRST : MODE_MAP_LAST, (T)HEAD_TAIL);
BiFunction m = first ?
((a, b) -> a == HEAD_TAIL ? mapper.apply(b) : (T)b) :
((a, b) -> b == HEAD_TAIL ? mapper.apply(a) : (T)a);
this.mapper = (BiFunction) m;
}
@SuppressWarnings("unchecked")
PSOfRef(Function boundMapper, Function elseMapper, Spliterator source, boolean first) {
super(source, first ? MODE_MAP_FIRST_OR_ELSE : MODE_MAP_LAST_OR_ELSE, (T)HEAD_TAIL);
this.mapper = first ?
((a, b) -> a == HEAD_TAIL ? boundMapper.apply(b) : elseMapper.apply(b)) :
((a, b) -> b == HEAD_TAIL ? boundMapper.apply(a) : elseMapper.apply(a));
}
@Override
public void accept(T t) {
cur = t;
}
private BiConsumer fn(Consumer action) {
return (a, b) -> action.accept(mapper.apply(a, b));
}
@Override
public boolean tryAdvance(Consumer action) {
Sink l = left, r = right;
if (l != null) {
left = null;
if (!source.tryAdvance(this)) {
right = null;
return l.connect(r, fn(action));
}
if (l.push(cur, fn(action), false))
return true;
}
T prev = cur;
if (!source.tryAdvance(this)) {
right = null;
return r != null && r.push(prev, fn(action), true);
}
action.accept(mapper.apply(prev, cur));
return true;
}
@Override
public void forEachRemaining(Consumer action) {
BiConsumer fn = fn(action);
source.forEachRemaining(next -> {
if (left != null) {
left.push(cur = next, fn, false);
left = null;
} else {
action.accept(mapper.apply(cur, cur = next));
}
});
finish(fn, cur);
}
@Override
public Spliterator tryAdvanceOrTail(Consumer action) {
if (mode != MODE_MAP_FIRST || right != EMPTY) {
return tryAdvance(action) ? this : null;
}
if (left != null) {
Sink l = left;
left = null;
source = TailSpliterator.tryAdvanceWithTail(source, this);
if (source == null) {
right = null;
return null;
}
if (l.push(cur, fn(action), false))
return this;
}
@SuppressWarnings("unchecked")
Spliterator s = (Spliterator)source;
source = null;
return s;
}
@Override
public Spliterator forEachOrTail(Consumer action) {
if(mode != MODE_MAP_FIRST || right != EMPTY) {
forEachRemaining(action);
return null;
}
while (true) {
Spliterator tail = tryAdvanceOrTail(action);
if (tail != this)
return tail;
}
}
}
static final class PSOfInt extends PairSpliterator implements
Spliterator.OfInt, IntConsumer {
private final IntBinaryOperator mapper;
private final IntUnaryOperator unaryMapper;
private int cur;
PSOfInt(IntBinaryOperator mapper, IntUnaryOperator unaryMapper, Spliterator.OfInt source, int mode) {
super(source, mode, null);
this.mapper = mapper;
this.unaryMapper = unaryMapper;
}
@Override
public void accept(int t) {
cur = t;
}
private BiConsumer fn(IntConsumer action) {
switch(mode) {
case MODE_MAP_FIRST:
return (a, b) -> action.accept(a == null ? unaryMapper.applyAsInt(b) : b);
case MODE_MAP_LAST:
return (a, b) -> action.accept(b == null ? unaryMapper.applyAsInt(a) : a);
default:
return (a, b) -> action.accept(mapper.applyAsInt(a, b));
}
}
@Override
public boolean tryAdvance(IntConsumer action) {
Sink l = left, r = right;
if (l != null) {
left = null;
if (!source.tryAdvance(this)) {
right = null;
return l.connect(r, fn(action));
}
if (l.push(cur, fn(action), false))
return true;
}
int prev = cur;
if (!source.tryAdvance(this)) {
right = null;
return r != null && r.push(prev, fn(action), true);
}
action.accept(mapper.applyAsInt(prev, cur));
return true;
}
@Override
public void forEachRemaining(IntConsumer action) {
BiConsumer fn = fn(action);
source.forEachRemaining((int next) -> {
if (left != null) {
left.push(cur = next, fn, false);
left = null;
} else {
action.accept(mapper.applyAsInt(cur, cur = next));
}
});
finish(fn, cur);
}
}
static final class PSOfLong extends PairSpliterator implements
Spliterator.OfLong, LongConsumer {
private final LongBinaryOperator mapper;
private final LongUnaryOperator unaryMapper;
private long cur;
PSOfLong(LongBinaryOperator mapper, LongUnaryOperator unaryMapper, Spliterator.OfLong source, int mode) {
super(source, mode, null);
this.mapper = mapper;
this.unaryMapper = unaryMapper;
}
@Override
public void accept(long t) {
cur = t;
}
private BiConsumer fn(LongConsumer action) {
switch(mode) {
case MODE_MAP_FIRST:
return (a, b) -> action.accept(a == null ? unaryMapper.applyAsLong(b) : b);
case MODE_MAP_LAST:
return (a, b) -> action.accept(b == null ? unaryMapper.applyAsLong(a) : a);
default:
return (a, b) -> action.accept(mapper.applyAsLong(a, b));
}
}
@Override
public boolean tryAdvance(LongConsumer action) {
Sink l = left, r = right;
if (l != null) {
left = null;
if (!source.tryAdvance(this)) {
right = null;
return l.connect(r, fn(action));
}
if (l.push(cur, fn(action), false))
return true;
}
long prev = cur;
if (!source.tryAdvance(this)) {
right = null;
return r != null && r.push(prev, fn(action), true);
}
action.accept(mapper.applyAsLong(prev, cur));
return true;
}
@Override
public void forEachRemaining(LongConsumer action) {
BiConsumer fn = fn(action);
source.forEachRemaining((long next) -> {
if (left != null) {
left.push(cur = next, fn, false);
left = null;
} else {
action.accept(mapper.applyAsLong(cur, cur = next));
}
});
finish(fn, cur);
}
}
static final class PSOfDouble extends PairSpliterator implements
Spliterator.OfDouble, DoubleConsumer {
private final DoubleBinaryOperator mapper;
private final DoubleUnaryOperator unaryMapper;
private double cur;
PSOfDouble(DoubleBinaryOperator mapper, DoubleUnaryOperator unaryMapper, Spliterator.OfDouble source, int mode) {
super(source, mode, null);
this.mapper = mapper;
this.unaryMapper = unaryMapper;
}
@Override
public void accept(double t) {
cur = t;
}
private BiConsumer fn(DoubleConsumer action) {
switch(mode) {
case MODE_MAP_FIRST:
return (a, b) -> action.accept(a == null ? unaryMapper.applyAsDouble(b) : b);
case MODE_MAP_LAST:
return (a, b) -> action.accept(b == null ? unaryMapper.applyAsDouble(a) : a);
default:
return (a, b) -> action.accept(mapper.applyAsDouble(a, b));
}
}
@Override
public boolean tryAdvance(DoubleConsumer action) {
Sink l = left, r = right;
if (l != null) {
left = null;
if (!source.tryAdvance(this)) {
right = null;
return l.connect(r, fn(action));
}
if (l.push(cur, fn(action), false))
return true;
}
double prev = cur;
if (!source.tryAdvance(this)) {
right = null;
return r != null && r.push(prev, fn(action), true);
}
action.accept(mapper.applyAsDouble(prev, cur));
return true;
}
@Override
public void forEachRemaining(DoubleConsumer action) {
BiConsumer fn = fn(action);
source.forEachRemaining((double next) -> {
if (left != null) {
left.push(cur = next, fn, false);
left = null;
} else {
action.accept(mapper.applyAsDouble(cur, cur = next));
}
});
finish(fn, cur);
}
}
}
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