asterixdb/asterix-runtime/src/main/java/org/apache/asterix/runtime/evaluators/functions/StringToCodePointDescriptor.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.asterix.runtime.evaluators.functions;

import java.io.DataOutput;
import java.io.IOException;

import org.apache.asterix.builders.OrderedListBuilder;
import org.apache.asterix.common.annotations.MissingNullInOutFunction;
import org.apache.asterix.formats.nontagged.SerializerDeserializerProvider;
import org.apache.asterix.om.base.AInt64;
import org.apache.asterix.om.base.AMutableInt64;
import org.apache.asterix.om.exceptions.ExceptionUtil;
import org.apache.asterix.om.functions.BuiltinFunctions;
import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
import org.apache.asterix.om.types.AOrderedListType;
import org.apache.asterix.om.types.ATypeTag;
import org.apache.asterix.om.types.BuiltinType;
import org.apache.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
import org.apache.hyracks.algebricks.runtime.base.IEvaluatorContext;
import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
import org.apache.hyracks.api.dataflow.value.ISerializerDeserializer;
import org.apache.hyracks.api.exceptions.HyracksDataException;
import org.apache.hyracks.data.std.api.IPointable;
import org.apache.hyracks.data.std.primitive.VoidPointable;
import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
import org.apache.hyracks.util.string.UTF8StringUtil;

@MissingNullInOutFunction
public class StringToCodePointDescriptor extends AbstractScalarFunctionDynamicDescriptor {

    private static final long serialVersionUID = 1L;

    public static final IFunctionDescriptorFactory FACTORY = StringToCodePointDescriptor::new;

    @Override
    public IScalarEvaluatorFactory createEvaluatorFactory(final IScalarEvaluatorFactory[] args) {
        return new IScalarEvaluatorFactory() {
            private static final long serialVersionUID = 1L;

            @Override
            public IScalarEvaluator createScalarEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
                return new IScalarEvaluator() {
                    protected final ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
                    protected final DataOutput out = resultStorage.getDataOutput();
                    protected final IPointable argPtr = new VoidPointable();
                    protected final IScalarEvaluator stringEval = args[0].createScalarEvaluator(ctx);
                    protected final AOrderedListType intListType = new AOrderedListType(BuiltinType.AINT64, null);

                    private OrderedListBuilder listBuilder = new OrderedListBuilder();
                    private ArrayBackedValueStorage inputVal = new ArrayBackedValueStorage();

                    @SuppressWarnings("unchecked")
                    private final ISerializerDeserializer<AInt64> int64Serde =
                            SerializerDeserializerProvider.INSTANCE.getSerializerDeserializer(BuiltinType.AINT64);
                    private final AMutableInt64 aInt64 = new AMutableInt64(0);

                    @Override
                    public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
                        try {
                            resultStorage.reset();
                            stringEval.evaluate(tuple, argPtr);

                            if (PointableHelper.checkAndSetMissingOrNull(result, argPtr)) {
                                return;
                            }

                            byte[] serString = argPtr.getByteArray();
                            int offset = argPtr.getStartOffset();

                            if (serString[offset] != ATypeTag.SERIALIZED_STRING_TYPE_TAG) {
                                PointableHelper.setNull(result);
                                ExceptionUtil.warnTypeMismatch(ctx, sourceLoc, getIdentifier(), serString[offset], 0,
                                        ATypeTag.STRING);
                                return;
                            }
                            int len = UTF8StringUtil.getUTFLength(serString, offset + 1);

                            int start = offset + 1 + UTF8StringUtil.getNumBytesToStoreLength(len);
                            int pos = 0;
                            listBuilder.reset(intListType);
                            while (pos < len) {
                                int codePoint = UTF8StringUtil.codePointAt(serString, start + pos);
                                pos += UTF8StringUtil.codePointSize(serString, start + pos);

                                inputVal.reset();
                                aInt64.setValue(codePoint);
                                int64Serde.serialize(aInt64, inputVal.getDataOutput());
                                listBuilder.addItem(inputVal);
                            }
                            listBuilder.write(out, true);
                            result.set(resultStorage);
                        } catch (IOException e1) {
                            throw HyracksDataException.create(e1);
                        }
                    }
                };
            }
        };
    }

    @Override
    public FunctionIdentifier getIdentifier() {
        return BuiltinFunctions.STRING_TO_CODEPOINT;
    }
}