OPENNLP-1927: Expand Hunspell dictionary support

opennlp-core/opennlp-runtime/src/main/java/opennlp/tools/stemmer/hunspell/HunspellAffixTable.java

@@ -0,0 +1,84 @@
+/*
+ * 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 opennlp.tools.stemmer.hunspell;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Affix tables with entry counts and source locations for validation errors. */
+final class HunspellAffixTable {
+
+  /** Prevents construction. */
+  private HunspellAffixTable() { }
+
+  /**
+   * An entry including the directive name.
+   *
+   * @param fields The tokenized entry.
+   * @param line The one-based source line.
+   */
+  record Entry(String[] fields, int line) { }
+
+  /**
+   * Checks a table header, entry count, and field counts.
+   *
+   * @param lines The tokenized affix content.
+   * @param tag The table directive.
+   * @param minimumFields The minimum fields in an entry, including the directive.
+   * @param maximumFields The maximum fields in an entry, including the directive.
+   * @return The entries, or null if the file has no declaration for this table.
+   * @throws IOException If the header, entries, or count is invalid.
+   */
+  static List<Entry> read(String[][] lines, String tag, int minimumFields, int maximumFields)
+      throws IOException {
+    final List<Entry> entries = new ArrayList<>();
+    int count = -1;
+    for (int i = 0; i < lines.length; i++) {
+      final String[] fields = lines[i];
+      if (fields.length == 0 || !tag.equals(fields[0])) {
+        continue;
+      }
+      if (count < 0) {
+        try {
+          if (fields.length != 2) {
+            throw new NumberFormatException();
+          }
+          count = Integer.parseInt(fields[1]);
+          if (count < 0) {
+            throw new NumberFormatException();
+          }
+        } catch (NumberFormatException e) {
+          throw new IOException("invalid " + tag + " count at line " + (i + 1), e);
+        }
+      } else {
+        if (fields.length < minimumFields || fields.length > maximumFields || entries.size() == count) {
+          throw new IOException("invalid " + tag + " entry at line " + (i + 1));
+        }
+        entries.add(new Entry(fields, i + 1));
+      }
+    }
+    if (count < 0) {
+      return null;
+    }
+    if (entries.size() != count) {
+      throw new IOException(tag + " header specifies " + count + " entries but found " + entries.size());
+    }
+    return entries;
+  }
+}

opennlp-core/opennlp-runtime/src/main/java/opennlp/tools/stemmer/hunspell/HunspellCompoundRule.java

@@ -0,0 +1,157 @@
+/*
+ * 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 opennlp.tools.stemmer.hunspell;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/** A compound flag sequence with optional and repeated elements. */
+final class HunspellCompoundRule {
+
+  /** Interprets a flag according to the affix file's FLAG setting. */
+  @FunctionalInterface
+  interface FlagReader {
+    /**
+     * Interprets one flag.
+     *
+     * @param text The encoded flag.
+     * @param line The source line.
+     * @return The flag value.
+     * @throws IOException If the flag is malformed.
+     */
+    int read(String text, int line) throws IOException;
+  }
+
+  /** Maximum elements in one compound pattern. */
+  private static final int MAX_ELEMENTS = 4096;
+
+  private static final String INVALID_PATTERN = "invalid COMPOUNDRULE at line ";
+
+  private final int[] flags;
+  private final char[] repetition;
+
+  /**
+   * Initializes a parsed compound pattern.
+   *
+   * @param flags The required flag at each position.
+   * @param repetition The position's repetition operator or a space.
+   */
+  private HunspellCompoundRule(int[] flags, char[] repetition) {
+    this.flags = flags;
+    this.repetition = repetition;
+  }
+
+  /**
+   * Parses a compound rule without using a regular-expression engine.
+   *
+   * @param pattern The rule text.
+   * @param line The source line.
+   * @param reader The flag decoder.
+   * @return The parsed rule.
+   * @throws IOException If the pattern or a flag is malformed.
+   */
+  static HunspellCompoundRule parse(String pattern, int line, FlagReader reader) throws IOException {
+    final List<Integer> flags = new ArrayList<>();
+    final StringBuilder repetitions = new StringBuilder();
+    for (int at = 0; at < pattern.length();) {
+      final String flag;
+      if (pattern.charAt(at) == '(') {
+        final int end = pattern.indexOf(')', at + 1);
+        if (end <= at + 1) {
+          throw new IOException(INVALID_PATTERN + line);
+        }
+        flag = pattern.substring(at + 1, end);
+        at = end + 1;
+      } else {
+        final int point = pattern.codePointAt(at);
+        if (point == '*' || point == '?' || point == ')') {
+          throw new IOException(INVALID_PATTERN + line);
+        }
+        final int end = at + Character.charCount(point);
+        flag = pattern.substring(at, end);
+        at = end;
+      }
+      flags.add(reader.read(flag, line));
+      if (flags.size() > MAX_ELEMENTS) {
+        throw new IOException("COMPOUNDRULE exceeds " + MAX_ELEMENTS + " elements at line " + line);
+      }
+      if (at < pattern.length() && (pattern.charAt(at) == '*' || pattern.charAt(at) == '?')) {
+        repetitions.append(pattern.charAt(at++));
+      } else {
+        repetitions.append(' ');
+      }
+    }
+    if (flags.isEmpty()) {
+      throw new IOException("empty COMPOUNDRULE at line " + line);
+    }
+    final int[] values = new int[flags.size()];
+    final char[] repetition = new char[flags.size()];
+    for (int i = 0; i < values.length; i++) {
+      values[i] = flags.get(i);
+      repetition[i] = repetitions.charAt(i);
+    }
+    return new HunspellCompoundRule(values, repetition);
+  }
+
+  /**
+   * Tests a sequence of selected homonyms. Each part consumes one flag position.
+   *
+   * @param parts The flags of one selected entry per compound part.
+   * @param complete Whether the sequence must complete the rule.
+   * @return Whether the sequence is permitted by this rule.
+   */
+  boolean matches(List<int[]> parts, boolean complete) {
+    boolean[] states = new boolean[flags.length + 1];
+    states[0] = true;
+    skipOptional(states);
+    for (int[] part : parts) {
+      final boolean[] next = new boolean[states.length];
+      for (int i = 0; i < flags.length; i++) {
+        if (states[i] && HunspellDictionary.contains(part, flags[i])) {
+          next[repetition[i] == '*' ? i : i + 1] = true;
+        }
+      }
+      skipOptional(next);
+      states = next;
+    }
+    if (complete) {
+      return states[flags.length];
+    }
+    for (boolean state : states) {
+      if (state) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Advances states through optional pattern elements.
+   *
+   * @param states The active pattern positions.
+   */
+  private void skipOptional(boolean[] states) {
+    for (int i = 0; i < flags.length; i++) {
+      if (states[i] && repetition[i] != ' ') {
+        states[i + 1] = true;
+      }
+    }
+  }
+
+}