/***********************************************************************************************************************
*
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.api.common.typeutils.base;
import java.io.IOException;
import eu.stratosphere.core.memory.DataInputView;
import eu.stratosphere.core.memory.MemorySegment;
import eu.stratosphere.types.StringValue;
public final class StringComparator extends BasicTypeComparator<String> {
private static final long serialVersionUID = 1L;
private static final int HIGH_BIT = 0x1 << 7;
private static final int HIGH_BIT2 = 0x1 << 13;
private static final int HIGH_BIT2_MASK = 0x3 << 6;
public StringComparator(boolean ascending) {
super(ascending);
}
@Override
public int compare(DataInputView firstSource, DataInputView secondSource) throws IOException {
String s1 = StringValue.readString(firstSource);
String s2 = StringValue.readString(secondSource);
int comp = s1.compareTo(s2);
return ascendingComparison ? comp : -comp;
}
@Override
public boolean supportsNormalizedKey() {
return true;
}
@Override
public boolean supportsSerializationWithKeyNormalization() {
return false;
}
@Override
public int getNormalizeKeyLen() {
return Integer.MAX_VALUE;
}
@Override
public boolean isNormalizedKeyPrefixOnly(int keyBytes) {
return true;
}
@Override
public void putNormalizedKey(String record, MemorySegment target, int offset, int len) {;
final int limit = offset + len;
final int end = record.length();
int pos = 0;
while (pos < end && offset < limit) {
char c = record.charAt(pos++);
if (c < HIGH_BIT) {
target.put(offset++, (byte) c);
}
else if (c < HIGH_BIT2) {
target.put(offset++, (byte) ((c >>> 7) | HIGH_BIT));
if (offset < limit) {
target.put(offset++, (byte) c);
}
}
else {
target.put(offset++, (byte) ((c >>> 10) | HIGH_BIT2_MASK));
if (offset < limit) {
target.put(offset++, (byte) (c >>> 2));
}
if (offset < limit) {
target.put(offset++, (byte) c);
}
}
}
while (offset < limit) {
target.put(offset++, (byte) 0);
}
}
@Override
public StringComparator duplicate() {
return new StringComparator(ascendingComparison);
}
}