content: /*
   * 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.external.input.record.reader.stream;
  
  import java.io.IOException;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.asterix.external.api.AsterixInputStream;
  import org.apache.asterix.external.util.ExternalDataConstants;
  import org.apache.hyracks.api.context.IHyracksTaskContext;
  
  public class EmptyLineSeparatedRecordReader extends StreamRecordReader {
  
      private static final List<String> recordReaderFormats =
              Collections.unmodifiableList(Arrays.asList(ExternalDataConstants.FORMAT_LINE_SEPARATED));
      private static final String REQUIRED_CONFIGS = "";
      protected Map<String, String> config;
  
      private boolean prevCharCR;
      private boolean prevCharLF;
      private int newlineLength;
      private int readLength;
  
      @Override
      public boolean hasNext() throws IOException {
          if (done) {
              return false;
          }
          if (!skipWhiteSpace()) {
              done = true;
              close();
              return false;
          }
          newlineLength = 0;
          prevCharCR = false;
          prevCharLF = false;
          record.reset();
          readLength = 0;
          do {
              int startPosn = bufferPosn; //starting from where we left off the last time
              if (bufferPosn >= bufferLength) {
                  startPosn = bufferPosn = 0;
                  bufferLength = reader.read(inputBuffer);
                  if (bufferLength <= 0) {
                      if (readLength > 0) {
                          record.endRecord();
                          return true;
                      }
                      close();
                      return false; //EOF
                  }
              }
              for (; bufferPosn < bufferLength; ++bufferPosn) { //search for two consecutive newlines
                  if (inputBuffer[bufferPosn] == ExternalDataConstants.LF) {
                      if (prevCharLF) {
                          // \n\n
                          ++bufferPosn; // at next invocation proceed from following byte
                          newlineLength = 2;
                          break;
                      } else if (prevCharCR) {
                          newlineLength += 1;
                      }
                      prevCharLF = true;
                  } else {
                      prevCharLF = false;
                  }
                  if (inputBuffer[bufferPosn] == ExternalDataConstants.CR) { //CR + notLF, we are at notLF
                      if (prevCharCR) {
                          // \cr\cr
                          newlineLength = 2;
                          break;
                      }
                      prevCharCR = true;
                  } else {
                      prevCharCR = false;
                  }
                  if (!(prevCharCR || prevCharLF)) {
                      newlineLength = 0;
                  }
              }
              readLength = bufferPosn - startPosn;
              if (readLength > 0) {
                  record.append(inputBuffer, startPosn, readLength);
              }
          } while (newlineLength < 2);
          record.endRecord();
          return true;
      }
  
      @Override
      public List<String> getRecordReaderFormats() {
          return recordReaderFormats;
      }
  
      @Override
      public String getRequiredConfigs() {
          return REQUIRED_CONFIGS;
      }
  
      private boolean skipWhiteSpace() throws IOException {
          // start by skipping white spaces
          while (true) {
              if (bufferPosn < bufferLength) {
                  if (!Character.isWhitespace(inputBuffer[bufferPosn])) {
                      return true;
                  }
                  bufferPosn++;
              } else {
                  // fill buffer
                  bufferPosn = 0;
                  bufferLength = reader.read(inputBuffer);
                  if (bufferLength < 0) {
                      return false;
                  }
              }
          }
      }
  
      @Override
      public void configure(IHyracksTaskContext ctx, AsterixInputStream inputStream, Map<String, String> config) {
          super.configure(inputStream, config);
          this.config = config;
      }
  }
  