content: package org.apache.lucene.analysis.hunspell;
  
  /**
   * 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.
   */
  
  import org.apache.lucene.analysis.CharArrayMap;
  import org.apache.lucene.util.Version;
  
  import java.io.*;
  import java.nio.charset.Charset;
  import java.nio.charset.CharsetDecoder;
  import java.text.ParseException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Locale;
  
  public class HunspellDictionary {
  
    static final HunspellWord NOFLAGS = new HunspellWord();
    
    private static final String PREFIX_KEY = "PFX";
    private static final String SUFFIX_KEY = "SFX";
    private static final String FLAG_KEY = "FLAG";
  
    private static final String NUM_FLAG_TYPE = "num";
    private static final String UTF8_FLAG_TYPE = "UTF-8";
    private static final String LONG_FLAG_TYPE = "long";
    
    private static final String PREFIX_CONDITION_REGEX_PATTERN = "%s.*";
    private static final String SUFFIX_CONDITION_REGEX_PATTERN = ".*%s";
  
    private static final boolean IGNORE_CASE_DEFAULT = false;
  
    private CharArrayMap<List<HunspellWord>> words;
    private CharArrayMap<List<HunspellAffix>> prefixes;
    private CharArrayMap<List<HunspellAffix>> suffixes;
  
    private FlagParsingStrategy flagParsingStrategy = new SimpleFlagParsingStrategy(); // Default flag parsing strategy
    private boolean ignoreCase = IGNORE_CASE_DEFAULT;
  
    private final Version version;
  
    /**
     * Creates a new HunspellDictionary containing the information read from the provided InputStreams to hunspell affix
     * and dictionary files
     *
     * @param affix InputStream for reading the hunspell affix file
     * @param dictionary InputStream for reading the hunspell dictionary file
     * @param version Lucene Version
     * @throws IOException Can be thrown while reading from the InputStreams
     * @throws ParseException Can be thrown if the content of the files does not meet expected formats
     */
    public HunspellDictionary(InputStream affix, InputStream dictionary, Version version) throws IOException, ParseException {
      this(affix, Arrays.asList(dictionary), version, IGNORE_CASE_DEFAULT);
    }
  
    /**
     * Creates a new HunspellDictionary containing the information read from the provided InputStreams to hunspell affix
     * and dictionary files
     *
     * @param affix InputStream for reading the hunspell affix file
     * @param dictionary InputStream for reading the hunspell dictionary file
     * @param version Lucene Version
     * @param ignoreCase If true, dictionary matching will be case insensitive
     * @throws IOException Can be thrown while reading from the InputStreams
     * @throws ParseException Can be thrown if the content of the files does not meet expected formats
     */
    public HunspellDictionary(InputStream affix, InputStream dictionary, Version version, boolean ignoreCase) throws IOException, ParseException {
      this(affix, Arrays.asList(dictionary), version, ignoreCase);
    }
  
    /**
     * Creates a new HunspellDictionary containing the information read from the provided InputStreams to hunspell affix
     * and dictionary files
     *
     * @param affix InputStream for reading the hunspell affix file
     * @param dictionaries InputStreams for reading the hunspell dictionary file
     * @param version Lucene Version
     * @param ignoreCase If true, dictionary matching will be case insensitive
     * @throws IOException Can be thrown while reading from the InputStreams
     * @throws ParseException Can be thrown if the content of the files does not meet expected formats
     */
    public HunspellDictionary(InputStream affix, List<InputStream> dictionaries, Version version, boolean ignoreCase) throws IOException, ParseException {
      this.version = version;
      this.ignoreCase = ignoreCase;
      String encoding = getDictionaryEncoding(affix);
      CharsetDecoder decoder = getJavaEncoding(encoding);
      readAffixFile(affix, decoder);
      words = new CharArrayMap<List<HunspellWord>>(version, 65535 /* guess */, this.ignoreCase);
      for (InputStream dictionary : dictionaries) {
        readDictionaryFile(dictionary, decoder);
      }
    }
  
    /**
     * Looks up HunspellWords that match the String created from the given char array, offset and length
     *
     * @param word Char array to generate the String from
     * @param offset Offset in the char array that the String starts at
     * @param length Length from the offset that the String is
     * @return List of HunspellWords that match the generated String, or {@code null} if none are found
     */
    public List<HunspellWord> lookupWord(char word[], int offset, int length) {
      return words.get(word, offset, length);
    }
  
    /**
     * Looks up HunspellAffix prefixes that have an append that matches the String created from the given char array, offset and length
     *
     * @param word Char array to generate the String from
     * @param offset Offset in the char array that the String starts at
     * @param length Length from the offset that the String is
     * @return List of HunspellAffix prefixes with an append that matches the String, or {@code null} if none are found
     */
    public List<HunspellAffix> lookupPrefix(char word[], int offset, int length) {
      return prefixes.get(word, offset, length);
    }
  
    /**
     * Looks up HunspellAffix suffixes that have an append that matches the String created from the given char array, offset and length
     *
     * @param word Char array to generate the String from
     * @param offset Offset in the char array that the String starts at
     * @param length Length from the offset that the String is
     * @return List of HunspellAffix suffixes with an append that matches the String, or {@code null} if none are found
     */
    public List<HunspellAffix> lookupSuffix(char word[], int offset, int length) {
      return suffixes.get(word, offset, length);
    }
  
    /**
     * Reads the affix file through the provided InputStream, building up the prefix and suffix maps
     *
     * @param affixStream InputStream to read the content of the affix file from
     * @param decoder CharsetDecoder to decode the content of the file
     * @throws IOException Can be thrown while reading from the InputStream
     */
    private void readAffixFile(InputStream affixStream, CharsetDecoder decoder) throws IOException {
      prefixes = new CharArrayMap<List<HunspellAffix>>(version, 8, ignoreCase);
      suffixes = new CharArrayMap<List<HunspellAffix>>(version, 8, ignoreCase);
      
      BufferedReader reader = new BufferedReader(new InputStreamReader(affixStream, decoder));
      String line = null;
      while ((line = reader.readLine()) != null) {
        if (line.startsWith(PREFIX_KEY)) {
          parseAffix(prefixes, line, reader, PREFIX_CONDITION_REGEX_PATTERN);
        } else if (line.startsWith(SUFFIX_KEY)) {
          parseAffix(suffixes, line, reader, SUFFIX_CONDITION_REGEX_PATTERN);
        } else if (line.startsWith(FLAG_KEY)) {
          // Assume that the FLAG line comes before any prefix or suffixes
          // Store the strategy so it can be used when parsing the dic file
          flagParsingStrategy = getFlagParsingStrategy(line);
        }
      }
      reader.close();
    }
  
    /**
     * Parses a specific affix rule putting the result into the provided affix map
     * 
     * @param affixes Map where the result of the parsing will be put
     * @param header Header line of the affix rule
     * @param reader BufferedReader to read the content of the rule from
     * @param conditionPattern {@link String#format(String, Object...)} pattern to be used to generate the condition regex
     *                         pattern
     * @throws IOException Can be thrown while reading the rule
     */
    private void parseAffix(CharArrayMap<List<HunspellAffix>> affixes,
                            String header,
                            BufferedReader reader,
                            String conditionPattern) throws IOException {
      String args[] = header.split("\\s+");
  
      boolean crossProduct = args[2].equals("Y");
      
      int numLines = Integer.parseInt(args[3]);
      for (int i = 0; i < numLines; i++) {
        String line = reader.readLine();
        String ruleArgs[] = line.split("\\s+");
  
        HunspellAffix affix = new HunspellAffix();
        
        affix.setFlag(flagParsingStrategy.parseFlag(ruleArgs[1]));
        affix.setStrip(ruleArgs[2].equals("0") ? "" : ruleArgs[2]);
  
        String affixArg = ruleArgs[3];
        
        int flagSep = affixArg.lastIndexOf('/');
        if (flagSep != -1) {
          char appendFlags[] = flagParsingStrategy.parseFlags(affixArg.substring(flagSep + 1));
          Arrays.sort(appendFlags);
          affix.setAppendFlags(appendFlags);
          affix.setAppend(affixArg.substring(0, flagSep));
        } else {
          affix.setAppend(affixArg);
        }
  
        String condition = ruleArgs[4];
        affix.setCondition(condition, String.format(conditionPattern, condition));
        affix.setCrossProduct(crossProduct);
        
        List<HunspellAffix> list = affixes.get(affix.getAppend());
        if (list == null) {
          list = new ArrayList<HunspellAffix>();
          affixes.put(affix.getAppend(), list);
        }
        
        list.add(affix);
      }
    }
  
    /**
     * Parses the encoding specificed in the affix file readable through the provided InputStream
     *
     * @param affix InputStream for reading the affix file
     * @return Encoding specified in the affix file
     * @throws IOException Can be thrown while reading from the InputStream
     * @throws ParseException Thrown if the first non-empty non-comment line read from the file does not adhere to the format {@code SET <encoding>}
     */
    private String getDictionaryEncoding(InputStream affix) throws IOException, ParseException {
      final StringBuilder encoding = new StringBuilder();
      for (;;) {
        encoding.setLength(0);
        int ch;
        while ((ch = affix.read()) >= 0) {
          if (ch == '\n') {
            break;
          }
          if (ch != '\r') {
            encoding.append((char)ch);
          }
        }
        if (
            encoding.length() == 0 || encoding.charAt(0) == '#' ||
            // this test only at the end as ineffective but would allow lines only containing spaces:
            encoding.toString().trim().length() == 0
        ) {
          if (ch < 0) {
            throw new ParseException("Unexpected end of affix file.", 0);
          }
          continue;
        }
        if ("SET ".equals(encoding.substring(0, 4))) {
          // cleanup the encoding string, too (whitespace)
          return encoding.substring(4).trim();
        }
        throw new ParseException("The first non-comment line in the affix file must "+
            "be a 'SET charset', was: '" + encoding +"'", 0);
      }
    }
  
    /**
     * Retrieves the CharsetDecoder for the given encoding.  Note, This isn't perfect as I think ISCII-DEVANAGARI and
     * MICROSOFT-CP1251 etc are allowed...
     *
     * @param encoding Encoding to retrieve the CharsetDecoder for
     * @return CharSetDecoder for the given encoding
     */
    private CharsetDecoder getJavaEncoding(String encoding) {
      Charset charset = Charset.forName(encoding);
      return charset.newDecoder();
    }
  
    /**
     * Determines the appropriate {@link FlagParsingStrategy} based on the FLAG definiton line taken from the affix file
     *
     * @param flagLine Line containing the flag information
     * @return FlagParsingStrategy that handles parsing flags in the way specified in the FLAG definiton
     */
    private FlagParsingStrategy getFlagParsingStrategy(String flagLine) {
      String flagType = flagLine.substring(5);
  
      if (NUM_FLAG_TYPE.equals(flagType)) {
        return new NumFlagParsingStrategy();
      } else if (UTF8_FLAG_TYPE.equals(flagType)) {
        return new SimpleFlagParsingStrategy();
      } else if (LONG_FLAG_TYPE.equals(flagType)) {
        return new DoubleASCIIFlagParsingStrategy();
      }
  
      throw new IllegalArgumentException("Unknown flag type: " + flagType);
    }
  
    /**
     * Reads the dictionary file through the provided InputStream, building up the words map
     *
     * @param dictionary InputStream to read the dictionary file through
     * @param decoder CharsetDecoder used to decode the contents of the file
     * @throws IOException Can be thrown while reading from the file
     */
    private void readDictionaryFile(InputStream dictionary, CharsetDecoder decoder) throws IOException {
      BufferedReader reader = new BufferedReader(new InputStreamReader(dictionary, decoder));
      // TODO: don't create millions of strings.
      String line = reader.readLine(); // first line is number of entries
      int numEntries = Integer.parseInt(line);
      
      // TODO: the flags themselves can be double-chars (long) or also numeric
      // either way the trick is to encode them as char... but they must be parsed differently
      while ((line = reader.readLine()) != null) {
        String entry;
        HunspellWord wordForm;
        
        int flagSep = line.lastIndexOf('/');
        if (flagSep == -1) {
          wordForm = NOFLAGS;
          entry = line;
        } else {
          // note, there can be comments (morph description) after a flag.
          // we should really look for any whitespace
          int end = line.indexOf('\t', flagSep);
          if (end == -1)
            end = line.length();
          
          
          wordForm = new HunspellWord(flagParsingStrategy.parseFlags(line.substring(flagSep + 1, end)));
          Arrays.sort(wordForm.getFlags());
          entry = line.substring(0, flagSep);
          if(ignoreCase) {
            entry = entry.toLowerCase(Locale.ENGLISH);
          }
        }
        
        List<HunspellWord> entries = words.get(entry);
        if (entries == null) {
          entries = new ArrayList<HunspellWord>();
          words.put(entry, entries);
        }
        entries.add(wordForm);
      }
    }
  
    public Version getVersion() {
      return version;
    }
  
    /**
     * Abstraction of the process of parsing flags taken from the affix and dic files
     */
    private static abstract class FlagParsingStrategy {
  
      /**
       * Parses the given String into a single flag
       *
       * @param rawFlag String to parse into a flag
       * @return Parsed flag
       */
      char parseFlag(String rawFlag) {
        return parseFlags(rawFlag)[0];
      }
  
      /**
       * Parses the given String into multiple flags
       *
       * @param rawFlags String to parse into flags
       * @return Parsed flags
       */
      abstract char[] parseFlags(String rawFlags);
    }
  
    /**
     * Simple implementation of {@link FlagParsingStrategy} that treats the chars in each String as a individual flags.
     * Can be used with both the ASCII and UTF-8 flag types.
     */
    private static class SimpleFlagParsingStrategy extends FlagParsingStrategy {
      /**
       * {@inheritDoc}
       */
      public char[] parseFlags(String rawFlags) {
        return rawFlags.toCharArray();
      }
    }
  
    /**
     * Implementation of {@link FlagParsingStrategy} that assumes each flag is encoded in its numerical form.  In the case
     * of multiple flags, each number is separated by a comma.
     */
    private static class NumFlagParsingStrategy extends FlagParsingStrategy {
      /**
       * {@inheritDoc}
       */
      public char[] parseFlags(String rawFlags) {
        String[] rawFlagParts = rawFlags.trim().split(",");
        char[] flags = new char[rawFlagParts.length];
  
        for (int i = 0; i < rawFlagParts.length; i++) {
          // note, removing the trailing X/leading I for nepali... what is the rule here?! 
          flags[i] = (char) Integer.parseInt(rawFlagParts[i].replaceAll("[^0-9]", ""));
        }
  
        return flags;
      }
    }
  
    /**
     * Implementation of {@link FlagParsingStrategy} that assumes each flag is encoded as two ASCII characters whose codes
     * must be combined into a single character.
     *
     * TODO (rmuir) test
     */
    private static class DoubleASCIIFlagParsingStrategy extends FlagParsingStrategy {
  
      /**
       * {@inheritDoc}
       */
      public char[] parseFlags(String rawFlags) {
        if (rawFlags.length() == 0) {
          return new char[0];
        }
  
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < rawFlags.length(); i+=2) {
          char cookedFlag = (char) ((int) rawFlags.charAt(i) + (int) rawFlags.charAt(i + 1));
          builder.append(cookedFlag);
        }
        
        char flags[] = new char[builder.length()];
        builder.getChars(0, builder.length(), flags, 0);
        return flags;
      }
    }
  
    public boolean isIgnoreCase() {
      return ignoreCase;
    }
  }
  