content: /************************************************************************************
   * This file is part of AndroidIDE.
   *
   *
   *
   * AndroidIDE is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * AndroidIDE is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
   *
   **************************************************************************************/
  /*******************************************************************************
   * Copyright (c) 2000, 2020 IBM Corporation and others.
   *
   * This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License 2.0
   * which accompanies this distribution, and is available at
   * https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   *
   * Contributors:
   *     IBM Corporation - initial API and implementation
   *     Luiz-Otavio Zorzella <zorzella at gmail dot com> - Improve CamelCase algorithm
   *     Gabor Kovesdan - Contribution for Bug 350000 - [content assist] Include non-prefix matches in auto-complete suggestions
   *     Stefan Xenos <sxenos@gmail.com> (Google) - Bug 501283 - Lots of hash collisions during indexing
   *******************************************************************************/
  package org.eclipse.jdt.core.compiler;
  
  import org.eclipse.jdt.internal.compiler.parser.ScannerHelper;
  
  import java.util.Arrays;
  import java.util.List;
  
  /**
   * This class is a collection of helper methods to manipulate char arrays.
   *
   * @since 2.1
   * @noinstantiate This class is not intended to be instantiated by clients.
   */
  public final class CharOperation {
  
    /** Constant for an empty char array */
    public static final char[] NO_CHAR = new char[0];
  
    /** Constant for an empty char array with two dimensions. */
    public static final char[][] NO_CHAR_CHAR = new char[0][];
  
    /**
     * Constant for an empty String array.
     *
     * @since 3.1
     */
    public static final String[] NO_STRINGS = new String[0];
  
    /**
     * Constant for all Prefix
     *
     * @since 3.14
     */
    public static final char[] ALL_PREFIX = new char[] {'*'};
  
    /**
     * Constant for comma
     *
     * @since 3.14
     */
    public static final char[] COMMA_SEPARATOR = new char[] {','};
  
    private static final int[] EMPTY_REGIONS = new int[0];
  
    /**
     * Answers a new array with appending the suffix character at the end of the array. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b' }
     *    suffix = 'c'
     *    => result = { 'a', 'b' , 'c' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = null
     *    suffix = 'c'
     *    => result = { 'c' }
     * </pre>
     * </ol>
     *
     * @param array the array that is concatenated with the suffix character
     * @param suffix the suffix character
     * @return the new array
     */
    public static final char[] append(char[] array, char suffix) {
      if (array == null) return new char[] {suffix};
      int length = array.length;
      System.arraycopy(array, 0, array = new char[length + 1], 0, length);
      array[length] = suffix;
      return array;
    }
  
    /**
     * Answers a new array with appending the sub-array at the end of the array. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b' }
     *    suffix = { 'c', 'd' }
     *    => result = { 'a', 'b' , 'c' , d' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = null
     *    suffix = { 'c' }
     *    => result = { 'c' }
     * </pre>
     * </ol>
     *
     * @param target the array that is concatenated with the suffix array.
     * @param suffix the array that will be concatenated to the target
     * @return the new array
     * @throws NullPointerException if the target array is null
     * @since 3.11
     */
    public static final char[] append(char[] target, char[] suffix) {
      if (suffix == null || suffix.length == 0) return target;
      int targetLength = target.length;
      int subLength = suffix.length;
      int newTargetLength = targetLength + subLength;
      if (newTargetLength > targetLength) {
        System.arraycopy(target, 0, target = new char[newTargetLength], 0, targetLength);
      }
      System.arraycopy(suffix, 0, target, targetLength, subLength);
      return target;
    }
  
    /**
     * Append the given sub-array to the target array starting at the given index in the target array.
     * The start of the sub-array is inclusive, the end is exclusive. Answers a new target array if it
     * needs to grow, otherwise answers the same target array. <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    target = { 'a', 'b', '0' }
     *    index = 2
     *    array = { 'c', 'd' }
     *    start = 0
     *    end = 1
     *    => result = { 'a', 'b' , 'c' }
     * </pre>
     *   <li>
     *       <pre>
     *    target = { 'a', 'b' }
     *    index = 2
     *    array = { 'c', 'd' }
     *    start = 0
     *    end = 1
     *    => result = { 'a', 'b' , 'c', '0', '0' , '0' } (new array)
     * </pre>
     *   <li>
     *       <pre>
     *    target = { 'a', 'b', 'c' }
     *    index = 1
     *    array = { 'c', 'd', 'e', 'f' }
     *    start = 1
     *    end = 4
     *    => result = { 'a', 'd' , 'e', 'f', '0', '0', '0', '0' } (new array)
     * </pre>
     * </ol>
     *
     * @param target the given target
     * @param index the given index
     * @param array the given array
     * @param start the given start index
     * @param end the given end index
     * @return the new array
     * @throws NullPointerException if the target array is null
     */
    public static final char[] append(char[] target, int index, char[] array, int start, int end) {
      int targetLength = target.length;
      int subLength = end - start;
      int newTargetLength = subLength + index;
      if (newTargetLength > targetLength) {
        System.arraycopy(target, 0, target = new char[newTargetLength * 2], 0, index);
      }
      System.arraycopy(array, start, target, index, subLength);
      return target;
    }
  
    /**
     * Answers a new array with prepending the prefix character at the start of the array. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    prefix = 'c'
     *    array = { 'a', 'b' }
     *    => result = { 'c' , 'a', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    prefix = 'c'
     *    array = null
     *    => result = { 'c' }
     * </pre>
     * </ol>
     *
     * @param array the array that is concatenated with the prefix character
     * @param prefix the prefix character
     * @return the new array
     * @since 3.14
     */
    public static final char[] prepend(char prefix, char[] array) {
      if (array == null) return new char[] {prefix};
      int length = array.length;
      System.arraycopy(array, 0, array = new char[length + 1], 1, length);
      array[0] = prefix;
      return array;
    }
  
    /**
     * Answers the concatenation of the two arrays. It answers null if the two arrays are null. If the
     * first array is null, then the second array is returned. If the second array is null, then the
     * first array is returned. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    => result = null
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { ' a' } }
     *    second = null
     *    => result = { { ' a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { { ' a' } }
     *    => result = { { ' a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { ' b' } }
     *    second = { { ' a' } }
     *    => result = { { ' b' }, { ' a' } }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the second array to concatenate
     * @return the concatenation of the two arrays, or null if the two arrays are null.
     */
    public static final char[][] arrayConcat(char[][] first, char[][] second) {
      if (first == null) return second;
      if (second == null) return first;
  
      int length1 = first.length;
      int length2 = second.length;
      char[][] result = new char[length1 + length2][];
      System.arraycopy(first, 0, result, 0, length1);
      System.arraycopy(second, 0, result, length1, length2);
      return result;
    }
  
    /**
     * Answers true if the pattern matches the given name using CamelCase rules, or false otherwise.
     * char[] CamelCase matching does NOT accept explicit wild-cards '*' and '?' and is inherently
     * case sensitive.
     *
     * <p>CamelCase denotes the convention of writing compound names without spaces, and capitalizing
     * every term. This function recognizes both upper and lower CamelCase, depending whether the
     * leading character is capitalized or not. The leading part of an upper CamelCase pattern is
     * assumed to contain a sequence of capitals which are appearing in the matching name; e.g. 'NPE'
     * will match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern uses a
     * lowercase first character. In Java, type names follow the upper CamelCase convention, whereas
     * method or field names follow the lower CamelCase convention.
     *
     * <p>The pattern may contain lowercase characters, which will be matched in a case sensitive way.
     * These characters must appear in sequence in the name. For instance, 'NPExcep' will match
     * 'NullPointerException', but not 'NullPointerExCEPTION' or 'NuPoEx' will match
     * 'NullPointerException', but not 'NoPointerException'.
     *
     * <p>Digit characters are treated in a special way. They can be used in the pattern but are not
     * always considered as leading character. For instance, both 'UTF16DSS' and 'UTFDSS' patterns
     * will match 'UTF16DocumentScannerSupport'.
     *
     * <p>Using this method allows matching names to have more parts than the specified pattern (see
     * {@link #camelCaseMatch(char[], char[], boolean)}).<br>
     * For instance, 'HM' , 'HaMa' and 'HMap' patterns will match 'HashMap', 'HatMapper' <b>and
     * also</b> 'HashMapEntry'.
     *
     * <p>Examples:
     *
     * <ol>
     *   <li>pattern = "NPE".toCharArray() name = "NullPointerException".toCharArray() result => true
     *   <li>pattern = "NPE".toCharArray() name = "NoPermissionException".toCharArray() result => true
     *   <li>pattern = "NuPoEx".toCharArray() name = "NullPointerException".toCharArray() result =>
     *       true
     *   <li>pattern = "NuPoEx".toCharArray() name = "NoPermissionException".toCharArray() result =>
     *       false
     *   <li>pattern = "npe".toCharArray() name = "NullPointerException".toCharArray() result => false
     *   <li>pattern = "IPL3".toCharArray() name = "IPerspectiveListener3".toCharArray() result =>
     *       true
     *   <li>pattern = "HM".toCharArray() name = "HashMapEntry".toCharArray() result => true
     * </ol>
     *
     * @param pattern the given pattern
     * @param name the given name
     * @return true if the pattern matches the given name, false otherwise
     * @since 3.2
     */
    public static final boolean camelCaseMatch(char[] pattern, char[] name) {
      if (pattern == null) return true; // null pattern is equivalent to '*'
      if (name == null) return false; // null name cannot match
  
      return camelCaseMatch(
          pattern, 0, pattern.length, name, 0, name.length, false /*not the same count of parts*/);
    }
  
    /**
     * Answers true if a sub-pattern matches the sub-part of the given name using CamelCase rules, or
     * false otherwise. char[] CamelCase matching does NOT accept explicit wild-cards '*' and '?' and
     * is inherently case sensitive. Can match only subset of name/pattern, considering end positions
     * as non-inclusive. The sub-pattern is defined by the patternStart and patternEnd positions.
     *
     * <p>CamelCase denotes the convention of writing compound names without spaces, and capitalizing
     * every term. This function recognizes both upper and lower CamelCase, depending whether the
     * leading character is capitalized or not. The leading part of an upper CamelCase pattern is
     * assumed to contain a sequence of capitals which are appearing in the matching name; e.g. 'NPE'
     * will match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern uses a
     * lowercase first character. In Java, type names follow the upper CamelCase convention, whereas
     * method or field names follow the lower CamelCase convention.
     *
     * <p>The pattern may contain lowercase characters, which will be matched in a case sensitive way.
     * These characters must appear in sequence in the name. For instance, 'NPExcep' will match
     * 'NullPointerException', but not 'NullPointerExCEPTION' or 'NuPoEx' will match
     * 'NullPointerException', but not 'NoPointerException'.
     *
     * <p>Digit characters are treated in a special way. They can be used in the pattern but are not
     * always considered as leading character. For instance, both 'UTF16DSS' and 'UTFDSS' patterns
     * will match 'UTF16DocumentScannerSupport'.
     *
     * <p>CamelCase can be restricted to match only the same count of parts. When this restriction is
     * specified the given pattern and the given name must have <b>exactly</b> the same number of
     * parts (i.e. the same number of uppercase characters).<br>
     * For instance, 'HM' , 'HaMa' and 'HMap' patterns will match 'HashMap' and 'HatMapper' <b>but
     * not</b> 'HashMapEntry'.
     *
     * <p>Examples:
     *
     * <ol>
     *   <li>pattern = "NPE".toCharArray() patternStart = 0 patternEnd = 3 name =
     *       "NullPointerException".toCharArray() nameStart = 0 nameEnd = 20 result => true
     *   <li>pattern = "NPE".toCharArray() patternStart = 0 patternEnd = 3 name =
     *       "NoPermissionException".toCharArray() nameStart = 0 nameEnd = 21 result => true
     *   <li>pattern = "NuPoEx".toCharArray() patternStart = 0 patternEnd = 6 name =
     *       "NullPointerException".toCharArray() nameStart = 0 nameEnd = 20 result => true
     *   <li>pattern = "NuPoEx".toCharArray() patternStart = 0 patternEnd = 6 name =
     *       "NoPermissionException".toCharArray() nameStart = 0 nameEnd = 21 result => false
     *   <li>pattern = "npe".toCharArray() patternStart = 0 patternEnd = 3 name =
     *       "NullPointerException".toCharArray() nameStart = 0 nameEnd = 20 result => false
     *   <li>pattern = "IPL3".toCharArray() patternStart = 0 patternEnd = 4 name =
     *       "IPerspectiveListener3".toCharArray() nameStart = 0 nameEnd = 21 result => true
     *   <li>pattern = "HM".toCharArray() patternStart = 0 patternEnd = 2 name =
     *       "HashMapEntry".toCharArray() nameStart = 0 nameEnd = 12 result => (samePartCount ==
     *       false)
     * </ol>
     *
     * @param pattern the given pattern
     * @param patternStart the start index of the pattern, inclusive
     * @param patternEnd the end index of the pattern, exclusive
     * @param name the given name
     * @param nameStart the start index of the name, inclusive
     * @param nameEnd the end index of the name, exclusive
     * @param samePartCount flag telling whether the pattern and the name should have the same count
     *     of parts or not.<br>
     *     &nbsp;&nbsp;For example:
     *     <ul>
     *       <li>'HM' type string pattern will match 'HashMap' and 'HtmlMapper' types, but not
     *           'HashMapEntry'
     *       <li>'HMap' type string pattern will still match previous 'HashMap' and 'HtmlMapper'
     *           types, but not 'HighMagnitude'
     *     </ul>
     *
     * @return true if a sub-pattern matches the sub-part of the given name, false otherwise
     * @since 3.4
     */
    public static final boolean camelCaseMatch(
        char[] pattern,
        int patternStart,
        int patternEnd,
        char[] name,
        int nameStart,
        int nameEnd,
        boolean samePartCount) {
  
      /* !!!!!!!!!! WARNING !!!!!!!!!!
       * The algorithm implemented in this method has been heavily used in
       * StringOperation#getCamelCaseMatchingRegions(String, int, int, String, int, int, boolean)
       * method.
       *
       * So, if any change needs to be applied in the current algorithm,
       * do NOT forget to also apply the same change in the StringOperation method!
       */
  
      if (name == null) return false; // null name cannot match
      if (pattern == null) return true; // null pattern is equivalent to '*'
      if (patternEnd < 0) patternEnd = pattern.length;
      if (nameEnd < 0) nameEnd = name.length;
  
      if (patternEnd <= patternStart) return nameEnd <= nameStart;
      if (nameEnd <= nameStart) return false;
      // check first pattern char
      if (name[nameStart] != pattern[patternStart]) {
        // first char must strictly match (upper/lower)
        return false;
      }
  
      char patternChar, nameChar;
      int iPattern = patternStart;
      int iName = nameStart;
  
      // Main loop is on pattern characters
      while (true) {
  
        iPattern++;
        iName++;
  
        if (iPattern == patternEnd) { // we have exhausted pattern...
          // it's a match if the name can have additional parts (i.e. uppercase characters) or
          // is also
          // exhausted
          if (!samePartCount || iName == nameEnd) return true;
  
          // otherwise it's a match only if the name has no more uppercase characters
          while (true) {
            if (iName == nameEnd) {
              // we have exhausted the name, so it's a match
              return true;
            }
            nameChar = name[iName];
            // test if the name character is uppercase
            if (nameChar < ScannerHelper.MAX_OBVIOUS) {
              if ((ScannerHelper.OBVIOUS_IDENT_CHAR_NATURES[nameChar] & ScannerHelper.C_UPPER_LETTER)
                  != 0) {
                return false;
              }
            } else if (!Character.isJavaIdentifierPart(nameChar) || Character.isUpperCase(nameChar)) {
              return false;
            }
            iName++;
          }
        }
  
        if (iName == nameEnd) {
          // We have exhausted the name (and not the pattern), so it's not a match
          return false;
        }
  
        // For as long as we're exactly matching, bring it on (even if it's a lower case
        // character)
        if ((patternChar = pattern[iPattern]) == name[iName]) {
          continue;
        }
  
        // If characters are not equals, then it's not a match if patternChar is lowercase
        if (patternChar < ScannerHelper.MAX_OBVIOUS) {
          if ((ScannerHelper.OBVIOUS_IDENT_CHAR_NATURES[patternChar]
                  & (ScannerHelper.C_UPPER_LETTER | ScannerHelper.C_DIGIT))
              == 0) {
            return false;
          }
        } else if (Character.isJavaIdentifierPart(patternChar)
            && !Character.isUpperCase(patternChar)
            && !Character.isDigit(patternChar)) {
          return false;
        }
  
        // patternChar is uppercase, so let's find the next uppercase in name
        while (true) {
          if (iName == nameEnd) {
            //	We have exhausted name (and not pattern), so it's not a match
            return false;
          }
  
          nameChar = name[iName];
          if (nameChar < ScannerHelper.MAX_OBVIOUS) {
            int charNature = ScannerHelper.OBVIOUS_IDENT_CHAR_NATURES[nameChar];
            if ((charNature & (ScannerHelper.C_LOWER_LETTER | ScannerHelper.C_SPECIAL)) != 0) {
              // nameChar is lowercase
              iName++;
            } else if ((charNature & ScannerHelper.C_DIGIT) != 0) {
              // nameChar is digit => break if the digit is current pattern character
              // otherwise
              // consume it
              if (patternChar == nameChar) break;
              iName++;
              // nameChar is uppercase...
            } else if (patternChar != nameChar) {
              // .. and it does not match patternChar, so it's not a match
              return false;
            } else {
              // .. and it matched patternChar. Back to the big loop
              break;
            }
          }
          // Same tests for non-obvious characters
          else if (Character.isJavaIdentifierPart(nameChar) && !Character.isUpperCase(nameChar)) {
            iName++;
          } else if (Character.isDigit(nameChar)) {
            if (patternChar == nameChar) break;
            iName++;
          } else if (patternChar != nameChar) {
            return false;
          } else {
            break;
          }
        }
        // At this point, either name has been exhausted, or it is at an uppercase letter.
        // Since pattern is also at an uppercase letter
      }
    }
  
    /**
     * Answers true if the pattern matches the given name using CamelCase rules, or false otherwise.
     * char[] CamelCase matching does NOT accept explicit wild-cards '*' and '?' and is inherently
     * case sensitive.
     *
     * <p>CamelCase denotes the convention of writing compound names without spaces, and capitalizing
     * every term. This function recognizes both upper and lower CamelCase, depending whether the
     * leading character is capitalized or not. The leading part of an upper CamelCase pattern is
     * assumed to contain a sequence of capitals which are appearing in the matching name; e.g. 'NPE'
     * will match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern uses a
     * lowercase first character. In Java, type names follow the upper CamelCase convention, whereas
     * method or field names follow the lower CamelCase convention.
     *
     * <p>The pattern may contain lowercase characters, which will be matched in a case sensitive way.
     * These characters must appear in sequence in the name. For instance, 'NPExcep' will match
     * 'NullPointerException', but not 'NullPointerExCEPTION' or 'NuPoEx' will match
     * 'NullPointerException', but not 'NoPointerException'.
     *
     * <p>Digit characters are treated in a special way. They can be used in the pattern but are not
     * always considered as leading character. For instance, both 'UTF16DSS' and 'UTFDSS' patterns
     * will match 'UTF16DocumentScannerSupport'.
     *
     * <p>CamelCase can be restricted to match only the same count of parts. When this restriction is
     * specified the given pattern and the given name must have <b>exactly</b> the same number of
     * parts (i.e. the same number of uppercase characters).<br>
     * For instance, 'HM' , 'HaMa' and 'HMap' patterns will match 'HashMap' and 'HatMapper' <b>but
     * not</b> 'HashMapEntry'.
     *
     * <p>Examples:
     *
     * <ol>
     *   <li>pattern = "NPE".toCharArray() name = "NullPointerException".toCharArray() result => true
     *   <li>pattern = "NPE".toCharArray() name = "NoPermissionException".toCharArray() result => true
     *   <li>pattern = "NuPoEx".toCharArray() name = "NullPointerException".toCharArray() result =>
     *       true
     *   <li>pattern = "NuPoEx".toCharArray() name = "NoPermissionException".toCharArray() result =>
     *       false
     *   <li>pattern = "npe".toCharArray() name = "NullPointerException".toCharArray() result => false
     *   <li>pattern = "IPL3".toCharArray() name = "IPerspectiveListener3".toCharArray() result =>
     *       true
     *   <li>pattern = "HM".toCharArray() name = "HashMapEntry".toCharArray() result => (samePartCount
     *       == false)
     * </ol>
     *
     * @param pattern the given pattern
     * @param name the given name
     * @param samePartCount flag telling whether the pattern and the name should have the same count
     *     of parts or not.<br>
     *     &nbsp;&nbsp;For example:
     *     <ul>
     *       <li>'HM' type string pattern will match 'HashMap' and 'HtmlMapper' types, but not
     *           'HashMapEntry'
     *       <li>'HMap' type string pattern will still match previous 'HashMap' and 'HtmlMapper'
     *           types, but not 'HighMagnitude'
     *     </ul>
     *
     * @return true if the pattern matches the given name, false otherwise
     * @since 3.4
     */
    public static final boolean camelCaseMatch(char[] pattern, char[] name, boolean samePartCount) {
      if (pattern == null) return true; // null pattern is equivalent to '*'
      if (name == null) return false; // null name cannot match
  
      return camelCaseMatch(pattern, 0, pattern.length, name, 0, name.length, samePartCount);
    }
  
    /**
     * Answers true if a sub-pattern matches the sub-part of the given name using CamelCase rules, or
     * false otherwise. char[] CamelCase matching does NOT accept explicit wild-cards '*' and '?' and
     * is inherently case sensitive. Can match only subset of name/pattern, considering end positions
     * as non-inclusive. The sub-pattern is defined by the patternStart and patternEnd positions.
     *
     * <p>CamelCase denotes the convention of writing compound names without spaces, and capitalizing
     * every term. This function recognizes both upper and lower CamelCase, depending whether the
     * leading character is capitalized or not. The leading part of an upper CamelCase pattern is
     * assumed to contain a sequence of capitals which are appearing in the matching name; e.g. 'NPE'
     * will match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern uses a
     * lowercase first character. In Java, type names follow the upper CamelCase convention, whereas
     * method or field names follow the lower CamelCase convention.
     *
     * <p>The pattern may contain lowercase characters, which will be matched in a case sensitive way.
     * These characters must appear in sequence in the name. For instance, 'NPExcep' will match
     * 'NullPointerException', but not 'NullPointerExCEPTION' or 'NuPoEx' will match
     * 'NullPointerException', but not 'NoPointerException'.
     *
     * <p>Digit characters are treated in a special way. They can be used in the pattern but are not
     * always considered as leading character. For instance, both 'UTF16DSS' and 'UTFDSS' patterns
     * will match 'UTF16DocumentScannerSupport'.
     *
     * <p>Digit characters are treated in a special way. They can be used in the pattern but are not
     * always considered as leading character. For instance, both 'UTF16DSS' and 'UTFDSS' patterns
     * will match 'UTF16DocumentScannerSupport'.
     *
     * <p>Using this method allows matching names to have more parts than the specified pattern (see
     * {@link #camelCaseMatch(char[], int, int, char[], int, int, boolean)}).<br>
     * For instance, 'HM' , 'HaMa' and 'HMap' patterns will match 'HashMap', 'HatMapper' <b>and
     * also</b> 'HashMapEntry'.
     *
     * <p>Examples:
     *
     * <ol>
     *   <li>pattern = "NPE".toCharArray() patternStart = 0 patternEnd = 3 name =
     *       "NullPointerException".toCharArray() nameStart = 0 nameEnd = 20 result => true
     *   <li>pattern = "NPE".toCharArray() patternStart = 0 patternEnd = 3 name =
     *       "NoPermissionException".toCharArray() nameStart = 0 nameEnd = 21 result => true
     *   <li>pattern = "NuPoEx".toCharArray() patternStart = 0 patternEnd = 6 name =
     *       "NullPointerException".toCharArray() nameStart = 0 nameEnd = 20 result => true
     *   <li>pattern = "NuPoEx".toCharArray() patternStart = 0 patternEnd = 6 name =
     *       "NoPermissionException".toCharArray() nameStart = 0 nameEnd = 21 result => false
     *   <li>pattern = "npe".toCharArray() patternStart = 0 patternEnd = 3 name =
     *       "NullPointerException".toCharArray() nameStart = 0 nameEnd = 20 result => false
     *   <li>pattern = "IPL3".toCharArray() patternStart = 0 patternEnd = 4 name =
     *       "IPerspectiveListener3".toCharArray() nameStart = 0 nameEnd = 21 result => true
     *   <li>pattern = "HM".toCharArray() patternStart = 0 patternEnd = 2 name =
     *       "HashMapEntry".toCharArray() nameStart = 0 nameEnd = 12 result => true
     * </ol>
     *
     * @param pattern the given pattern
     * @param patternStart the start index of the pattern, inclusive
     * @param patternEnd the end index of the pattern, exclusive
     * @param name the given name
     * @param nameStart the start index of the name, inclusive
     * @param nameEnd the end index of the name, exclusive
     * @return true if a sub-pattern matches the sub-part of the given name, false otherwise
     * @since 3.2
     */
    public static final boolean camelCaseMatch(
        char[] pattern, int patternStart, int patternEnd, char[] name, int nameStart, int nameEnd) {
      return camelCaseMatch(
          pattern,
          patternStart,
          patternEnd,
          name,
          nameStart,
          nameEnd,
          false /*not the same count of parts*/);
    }
  
    /**
     * Answers true if the characters of the pattern are contained in the name as a substring, in a
     * case-insensitive way.
     *
     * @param pattern the given pattern
     * @param name the given name
     * @return true if the pattern matches the given name, false otherwise
     * @since 3.12
     */
    public static final boolean substringMatch(String pattern, String name) {
      if (pattern == null || pattern.length() == 0) {
        return true;
      }
      if (name == null) {
        return false;
      }
      return checkSubstringMatch(pattern.toCharArray(), name.toCharArray());
    }
  
    /**
     * Internal substring matching method; called after the null and length checks are performed.
     *
     * @param pattern the given pattern
     * @param name the given name
     * @return true if the pattern matches the given name, false otherwise
     * @see CharOperation#substringMatch(char[], char[])
     */
    private static final boolean checkSubstringMatch(char[] pattern, char[] name) {
  
      /* XXX: to be revised/enabled
  
      	// allow non-consecutive occurrence of pattern characters
      	if (pattern.length >= 3) {
      		int pidx = 0;
  
      		for (int nidx = 0; nidx < name.length; nidx++) {
      			if (Character.toLowerCase(name[nidx]) ==
      					Character.toLowerCase(pattern[pidx]))
      				pidx++;
      			if (pidx == pattern.length)
      				return true;
      		}
  
      	// for short patterns only allow consecutive occurrence
      	} else {
      */
      // outer loop iterates on the characters of the name; trying to
      // match at any possible position
      outer:
      for (int nidx = 0; nidx < name.length - pattern.length + 1; nidx++) {
        // inner loop iterates on pattern characters
        for (int pidx = 0; pidx < pattern.length; pidx++) {
          if (Character.toLowerCase(name[nidx + pidx]) != Character.toLowerCase(pattern[pidx])) {
            // no match until parameter list; do not match parameter list
            if ((name[nidx + pidx] == '(') || (name[nidx + pidx] == ':')) return false;
            continue outer;
          }
          if (pidx == pattern.length - 1) return true;
        }
      }
      // XXX: }
  
      return false;
    }
  
    /**
     * Answers true if the characters of the pattern are contained in the name as a substring, in a
     * case-insensitive way.
     *
     * @param pattern the given pattern
     * @param name the given name
     * @return true if the pattern matches the given name, false otherwise
     * @since 3.12
     */
    public static final boolean substringMatch(char[] pattern, char[] name) {
      if (pattern == null || pattern.length == 0) {
        return true;
      }
      if (name == null) {
        return false;
      }
      return checkSubstringMatch(pattern, name);
    }
  
    /**
     * Returns the char arrays as an array of Strings
     *
     * @param charArrays the char array to convert
     * @return the char arrays as an array of Strings or null if the given char arrays is null.
     * @since 3.0
     */
    public static String[] charArrayToStringArray(char[][] charArrays) {
      if (charArrays == null) return null;
      int length = charArrays.length;
      if (length == 0) return NO_STRINGS;
      String[] strings = new String[length];
      for (int i = 0; i < length; i++) strings[i] = new String(charArrays[i]);
      return strings;
    }
  
    /**
     * Returns the char array as a String
     *
     * @param charArray the char array to convert
     * @return the char array as a String or null if the given char array is null.
     * @since 3.0
     */
    public static String charToString(char[] charArray) {
      if (charArray == null) return null;
      return new String(charArray);
    }
  
    /**
     * Converts the given list of strings to an array of equal size, containing the individual strings
     * converted to char[] each.
     *
     * @param stringList
     * @return an array of char[], representing the elements in the input list, or {@code null} if the
     *     list was {@code null}.
     * @since 3.14
     */
    public static char[][] toCharArrays(List<String> stringList) {
      if (stringList == null) return null;
      char[][] result = new char[stringList.size()][];
      for (int i = 0; i < result.length; i++) result[i] = stringList.get(i).toCharArray();
      return result;
    }
    /**
     * Answers a new array adding the second array at the end of first array. It answers null if the
     * first and second are null. If the first array is null, then a new array char[][] is created
     * with second. If the second array is null, then the first array is returned. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { 'a' }
     *    => result = { { ' a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { ' a' } }
     *    second = null
     *    => result = { { ' a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { ' a' } }
     *    second = { ' b' }
     *    => result = { { ' a' } , { ' b' } }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the array to add at the end of the first array
     * @return a new array adding the second array at the end of first array, or null if the two
     *     arrays are null.
     */
    public static final char[][] arrayConcat(char[][] first, char[] second) {
      if (second == null) return first;
      if (first == null) return new char[][] {second};
  
      int length = first.length;
      char[][] result = new char[length + 1][];
      System.arraycopy(first, 0, result, 0, length);
      result[length] = second;
      return result;
    }
    /**
     * Compares the two char arrays lexicographically.
     *
     * <p>Returns a negative integer if array1 lexicographically precedes the array2, a positive
     * integer if this array1 lexicographically follows the array2, or zero if both arrays are equal.
     *
     * @param array1 the first given array
     * @param array2 the second given array
     * @return the returned value of the comparison between array1 and array2
     * @throws NullPointerException if one of the arrays is null
     * @since 3.3
     */
    public static final int compareTo(char[] array1, char[] array2) {
      int length1 = array1.length;
      int length2 = array2.length;
      int min = Math.min(length1, length2);
      for (int i = 0; i < min; i++) {
        if (array1[i] != array2[i]) {
          return array1[i] - array2[i];
        }
      }
      return length1 - length2;
    }
    /**
     * Compares the two char arrays lexicographically between the given start and end positions.
     *
     * <p>Returns a negative integer if array1 lexicographically precedes the array2, a positive
     * integer if this array1 lexicographically follows the array2, or zero if both arrays are equal.
     *
     * <p>The comparison is done between start and end positions.
     *
     * @param array1 the first given array
     * @param array2 the second given array
     * @param start the starting position to compare (inclusive)
     * @param end the ending position to compare (exclusive)
     * @return the returned value of the comparison between array1 and array2
     * @throws NullPointerException if one of the arrays is null
     * @since 3.7.1
     */
    public static final int compareTo(char[] array1, char[] array2, int start, int end) {
      int length1 = array1.length;
      int length2 = array2.length;
      int min = Math.min(length1, length2);
      min = Math.min(min, end);
      for (int i = start; i < min; i++) {
        if (array1[i] != array2[i]) {
          return array1[i] - array2[i];
        }
      }
      return length1 - length2;
    }
    /**
     * Compares the contents of the two arrays array and prefix. Returns
     *
     * <ul>
     *   <li>zero if the array starts with the prefix contents
     *   <li>the difference between the first two characters that are not equal
     *   <li>one if array length is lower than the prefix length and that the prefix starts with the
     *       array contents.
     * </ul>
     *
     * <p>For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = null
     *    prefix = null
     *    => result = NullPointerException
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b', 'c', 'd', 'e' }
     *    prefix = { 'a', 'b', 'c'}
     *    => result = 0
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b', 'c', 'd', 'e' }
     *    prefix = { 'a', 'B', 'c'}
     *    => result = 32
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'd', 'b', 'c', 'd', 'e' }
     *    prefix = { 'a', 'b', 'c'}
     *    => result = 3
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b', 'c', 'd', 'e' }
     *    prefix = { 'd', 'b', 'c'}
     *    => result = -3
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'a', 'c', 'd', 'e' }
     *    prefix = { 'a', 'e', 'c'}
     *    => result = -4
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param prefix the given prefix
     * @return the result of the comparison (>=0 if array>prefix)
     * @throws NullPointerException if either array or prefix is null
     */
    public static final int compareWith(char[] array, char[] prefix) {
      int arrayLength = array.length;
      int prefixLength = prefix.length;
      int min = Math.min(arrayLength, prefixLength);
      int i = 0;
      while (min-- != 0) {
        char c1 = array[i];
        char c2 = prefix[i++];
        if (c1 != c2) return c1 - c2;
      }
      if (prefixLength == i) return 0;
      return -1; // array is shorter than prefix (e.g. array:'ab' < prefix:'abc').
    }
  
    /**
     * Answers the concatenation of the three arrays. It answers null if the three arrays are null. If
     * first is null, it answers the concatenation of second and third. If second is null, it answers
     * the concatenation of first and third. If third is null, it answers the concatenation of first
     * and second. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { 'a' }
     *    third = { 'b' }
     *    => result = { ' a', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = null
     *    third = { 'b' }
     *    => result = { ' a', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'b' }
     *    third = null
     *    => result = { ' a', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    third = null
     *    => result = null
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'b' }
     *    third = { 'c' }
     *    => result = { 'a', 'b', 'c' }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the second array to concatenate
     * @param third the third array to concatenate
     * @return the concatenation of the three arrays, or null if the three arrays are null.
     */
    public static final char[] concat(char[] first, char[] second, char[] third) {
      if (first == null) return concat(second, third);
      if (second == null) return concat(first, third);
      if (third == null) return concat(first, second);
  
      int length1 = first.length;
      int length2 = second.length;
      int length3 = third.length;
      char[] result = new char[length1 + length2 + length3];
      System.arraycopy(first, 0, result, 0, length1);
      System.arraycopy(second, 0, result, length1, length2);
      System.arraycopy(third, 0, result, length1 + length2, length3);
      return result;
    }
  
    /**
     * Answers the concatenation of the two arrays. It answers null if the two arrays are null. If the
     * first array is null, then the second array is returned. If the second array is null, then the
     * first array is returned. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { 'a' }
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = null
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = { ' b' }
     *    => result = { ' a' , ' b' }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the second array to concatenate
     * @return the concatenation of the two arrays, or null if the two arrays are null.
     */
    public static final char[] concat(char[] first, char[] second) {
      if (first == null) return second;
      if (second == null) return first;
  
      int length1 = first.length;
      int length2 = second.length;
      char[] result = new char[length1 + length2];
      System.arraycopy(first, 0, result, 0, length1);
      System.arraycopy(second, 0, result, length1, length2);
      return result;
    }
  
    /**
     * Answers the concatenation of the two arrays inserting the separator character between the two
     * arrays. Differs from {@link CharOperation#contains(char, char[])} in case second array is a
     * zero length array. It answers null if the two arrays are null. If the first array is null, then
     * the second array is returned. If the second array is null, then the first array is returned. if
     * the second array is zero length array, the separator is appended. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { 'a' }
     *    separator = '/'
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = null
     *    separator = '/'
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = { ' b' }
     *    separator = '/'
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = { '' }
     *    separator = '.'
     *    => result = { ' a' , '.', }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the second array to concatenate
     * @param separator the character to insert
     * @return the concatenation of the two arrays inserting the separator character between the two
     *     arrays , or null if the two arrays are null. If second array is of zero length, the
     *     separator is appended to the first array and returned.
     * @since 3.14
     */
    public static final char[] concatAll(char[] first, char[] second, char separator) {
      if (first == null) return second;
      if (second == null) return first;
  
      int length1 = first.length;
      if (length1 == 0) return second;
      int length2 = second.length;
  
      char[] result = new char[length1 + length2 + 1];
      System.arraycopy(first, 0, result, 0, length1);
      result[length1] = separator;
      if (length2 > 0) System.arraycopy(second, 0, result, length1 + 1, length2);
      return result;
    }
  
    /**
     * Answers the concatenation of the three arrays inserting the sep1 character between the first
     * two arrays and sep2 between the last two. It answers null if the three arrays are null. If the
     * first array is null or empty, then it answers the concatenation of second and third inserting
     * the sep2 character between them. If the second array is null or empty, then it answers the
     * concatenation of first and third inserting the sep1 character between them. If the third array
     * is null or empty, then it answers the concatenation of first and second inserting the sep1
     * character between them. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    sep1 = '/'
     *    second = { 'a' }
     *    sep2 = ':'
     *    third = { 'b' }
     *    => result = { ' a' , ':', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = null
     *    sep2 = ':'
     *    third = { 'b' }
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = { 'b' }
     *    sep2 = ':'
     *    third = null
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = { 'b' }
     *    sep2 = ':'
     *    third = { 'c' }
     *    => result = { ' a' , '/', 'b' , ':', 'c' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = { }
     *    sep2 = ':'
     *    third = { 'c' }
     *    => result = { ' a', ':', 'c' }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param sep1 the character to insert
     * @param second the second array to concatenate
     * @param sep2 the character to insert
     * @param third the second array to concatenate
     * @return the concatenation of the three arrays inserting the sep1 character between the two
     *     arrays and sep2 between the last two.
     * @since 3.12
     */
    public static final char[] concatNonEmpty(
        char[] first, char sep1, char[] second, char sep2, char[] third) {
      if (first == null || first.length == 0) return concatNonEmpty(second, third, sep2);
      if (second == null || second.length == 0) return concatNonEmpty(first, third, sep1);
      if (third == null || third.length == 0) return concatNonEmpty(first, second, sep1);
  
      return concat(first, sep1, second, sep2, third);
    }
  
    /**
     * Answers the concatenation of the three arrays inserting the sep1 character between the first
     * two arrays and sep2 between the last two. It answers null if the three arrays are null. If the
     * first array is null, then it answers the concatenation of second and third inserting the sep2
     * character between them. If the second array is null, then it answers the concatenation of first
     * and third inserting the sep1 character between them. If the third array is null, then it
     * answers the concatenation of first and second inserting the sep1 character between them. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    sep1 = '/'
     *    second = { 'a' }
     *    sep2 = ':'
     *    third = { 'b' }
     *    => result = { ' a' , ':', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = null
     *    sep2 = ':'
     *    third = { 'b' }
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = { 'b' }
     *    sep2 = ':'
     *    third = null
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    sep1 = '/'
     *    second = { 'b' }
     *    sep2 = ':'
     *    third = { 'c' }
     *    => result = { ' a' , '/', 'b' , ':', 'c' }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param sep1 the character to insert
     * @param second the second array to concatenate
     * @param sep2 the character to insert
     * @param third the second array to concatenate
     * @return the concatenation of the three arrays inserting the sep1 character between the two
     *     arrays and sep2 between the last two.
     */
    public static final char[] concat(
        char[] first, char sep1, char[] second, char sep2, char[] third) {
      if (first == null) return concat(second, third, sep2);
      if (second == null) return concat(first, third, sep1);
      if (third == null) return concat(first, second, sep1);
  
      int length1 = first.length;
      int length2 = second.length;
      int length3 = third.length;
      char[] result = new char[length1 + length2 + length3 + 2];
      System.arraycopy(first, 0, result, 0, length1);
      result[length1] = sep1;
      System.arraycopy(second, 0, result, length1 + 1, length2);
      result[length1 + length2 + 1] = sep2;
      System.arraycopy(third, 0, result, length1 + length2 + 2, length3);
      return result;
    }
    /**
     * Answers the concatenation of the two arrays inserting the separator character between the two
     * arrays. It answers null if the two arrays are null. If the first array is null or is empty,
     * then the second array is returned. If the second array is null or is empty, then the first
     * array is returned. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { 'a' }
     *    separator = '/'
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = null
     *    separator = '/'
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = { ' b' }
     *    separator = '/'
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = {  }
     *    separator = '/'
     *    => result = { ' a'}
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the second array to concatenate
     * @param separator the character to insert
     * @return the concatenation of the two arrays inserting the separator character between the two
     *     arrays , or null if the two arrays are null.
     * @since 3.12
     */
    public static final char[] concatNonEmpty(char[] first, char[] second, char separator) {
      if (first == null || first.length == 0) return second;
      if (second == null || second.length == 0) return first;
      return concat(first, second, separator);
    }
  
    /**
     * Answers the concatenation of the two arrays inserting the separator character between the two
     * arrays. It answers null if the two arrays are null. If the first array is null, then the second
     * array is returned. If the second array is null, then the first array is returned. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = { 'a' }
     *    separator = '/'
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = null
     *    separator = '/'
     *    => result = { ' a' }
     * </pre>
     *   <li>
     *       <pre>
     *    first = { ' a' }
     *    second = { ' b' }
     *    separator = '/'
     *    => result = { ' a' , '/', 'b' }
     * </pre>
     * </ol>
     *
     * @param first the first array to concatenate
     * @param second the second array to concatenate
     * @param separator the character to insert
     * @return the concatenation of the two arrays inserting the separator character between the two
     *     arrays , or null if the two arrays are null.
     */
    public static final char[] concat(char[] first, char[] second, char separator) {
      if (first == null) return second;
      if (second == null) return first;
  
      int length1 = first.length;
      if (length1 == 0) return second;
      int length2 = second.length;
      if (length2 == 0) return first;
  
      char[] result = new char[length1 + length2 + 1];
      System.arraycopy(first, 0, result, 0, length1);
      result[length1] = separator;
      System.arraycopy(second, 0, result, length1 + 1, length2);
      return result;
    }
  
    /**
     * Answers a new array with prepending the prefix character and appending the suffix character at
     * the end of the array. If array is null, it answers a new array containing the prefix and the
     * suffix characters. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    prefix = 'a'
     *    array = { 'b' }
     *    suffix = 'c'
     *    => result = { 'a', 'b' , 'c' }
     * </pre>
     *   <li>
     *       <pre>
     *    prefix = 'a'
     *    array = null
     *    suffix = 'c'
     *    => result = { 'a', 'c' }
     * </pre>
     * </ol>
     *
     * @param prefix the prefix character
     * @param array the array that is concatenated with the prefix and suffix characters
     * @param suffix the suffix character
     * @return the new array
     */
    public static final char[] concat(char prefix, char[] array, char suffix) {
      if (array == null) return new char[] {prefix, suffix};
  
      int length = array.length;
      char[] result = new char[length + 2];
      result[0] = prefix;
      System.arraycopy(array, 0, result, 1, length);
      result[length + 1] = suffix;
      return result;
    }
  
    /**
     * Answers the concatenation of the given array parts using the given separator between each part
     * and prepending the given name at the beginning. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    name = { 'c' }
     *    array = { { 'a' }, { 'b' } }
     *    separator = '.'
     *    => result = { 'a', '.', 'b' , '.', 'c' }
     * </pre>
     *   <li>
     *       <pre>
     *    name = null
     *    array = { { 'a' }, { 'b' } }
     *    separator = '.'
     *    => result = { 'a', '.', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    name = { ' c' }
     *    array = null
     *    separator = '.'
     *    => result = { 'c' }
     * </pre>
     * </ol>
     *
     * @param name the given name
     * @param array the given array
     * @param separator the given separator
     * @return the concatenation of the given array parts using the given separator between each part
     *     and prepending the given name at the beginning
     */
    public static final char[] concatWith(char[] name, char[][] array, char separator) {
      int nameLength = name == null ? 0 : name.length;
      if (nameLength == 0) return concatWith(array, separator);
  
      int length = array == null ? 0 : array.length;
      if (length == 0) return name;
  
      int size = nameLength;
      int index = length;
      while (--index >= 0) if (array[index].length > 0) size += array[index].length + 1;
      char[] result = new char[size];
      index = size;
      for (int i = length - 1; i >= 0; i--) {
        int subLength = array[i].length;
        if (subLength > 0) {
          index -= subLength;
          System.arraycopy(array[i], 0, result, index, subLength);
          result[--index] = separator;
        }
      }
      System.arraycopy(name, 0, result, 0, nameLength);
      return result;
    }
  
    /**
     * Answers the concatenation of the given array parts using the given separator between each part.
     * <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { { 'a' }, { 'b' } }
     *    separator = '.'
     *    => result = { 'a', '.', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = null
     *    separator = '.'
     *    => result = { }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param separator the given separator
     * @return the concatenation of the given array parts using the given separator between each part
     */
    public static final char[] concatWith(char[][] array, char separator) {
      int length = array == null ? 0 : array.length;
      if (length == 0) return CharOperation.NO_CHAR;
  
      int size = length - 1;
      int index = length;
      while (--index >= 0) {
        if (array[index].length == 0) size--;
        else size += array[index].length;
      }
      if (size <= 0) return CharOperation.NO_CHAR;
      char[] result = new char[size];
      index = length;
      while (--index >= 0) {
        length = array[index].length;
        if (length > 0) {
          System.arraycopy(array[index], 0, result, (size -= length), length);
          if (--size >= 0) result[size] = separator;
        }
      }
      return result;
    }
  
    /**
     * Answers the concatenation of the given array parts using the given separator between each part
     * and appending the given name at the end. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    name = { 'c' }
     *    array = { { 'a' }, { 'b' } }
     *    separator = '.'
     *    => result = { 'a', '.', 'b' , '.', 'c' }
     * </pre>
     *   <li>
     *       <pre>
     *    name = null
     *    array = { { 'a' }, { 'b' } }
     *    separator = '.'
     *    => result = { 'a', '.', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    name = { ' c' }
     *    array = null
     *    separator = '.'
     *    => result = { 'c' }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param name the given name
     * @param separator the given separator
     * @return the concatenation of the given array parts using the given separator between each part
     *     and appending the given name at the end
     */
    public static final char[] concatWith(char[][] array, char[] name, char separator) {
      int nameLength = name == null ? 0 : name.length;
      if (nameLength == 0) return concatWith(array, separator);
  
      int length = array == null ? 0 : array.length;
      if (length == 0) return name;
  
      int size = nameLength;
      int index = length;
      while (--index >= 0) if (array[index].length > 0) size += array[index].length + 1;
      char[] result = new char[size];
      index = 0;
      for (int i = 0; i < length; i++) {
        int subLength = array[i].length;
        if (subLength > 0) {
          System.arraycopy(array[i], 0, result, index, subLength);
          index += subLength;
          result[index++] = separator;
        }
      }
      System.arraycopy(name, 0, result, index, nameLength);
      return result;
    }
  
    /**
     * Answers the concatenation of the given array parts using the given separator between each part
     * irrespective of whether an element is a zero length array or not. <br>
     * <br>
     * For example:<br>
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { { 'a' }, {}, { 'b' } }
     *    separator = ''
     *    => result = { 'a', '/', '/', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { { 'a' }, { 'b' } }
     *    separator = '.'
     *    => result = { 'a', '.', 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = null
     *    separator = '.'
     *    => result = { }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param separator the given separator
     * @return the concatenation of the given array parts using the given separator between each part
     * @since 3.12
     */
    public static final char[] concatWithAll(char[][] array, char separator) {
      int length = array == null ? 0 : array.length;
      if (length == 0) return CharOperation.NO_CHAR;
  
      int size = length - 1;
      int index = length;
      while (--index >= 0) {
        size += array[index].length;
      }
      char[] result = new char[size];
      index = length;
      while (--index >= 0) {
        length = array[index].length;
        if (length > 0) {
          System.arraycopy(array[index], 0, result, (size -= length), length);
        }
        if (--size >= 0) result[size] = separator;
      }
      return result;
    }
  
    /**
     * Answers true if the array contains an occurrence of character, false otherwise. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    character = 'c'
     *    array = { { ' a' }, { ' b' } }
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    character = 'a'
     *    array = { { ' a' }, { ' b' } }
     *    result => true
     * </pre>
     * </ol>
     *
     * @param character the character to search
     * @param array the array in which the search is done
     * @return true if the array contains an occurrence of character, false otherwise.
     * @throws NullPointerException if array is null.
     */
    public static final boolean contains(char character, char[][] array) {
      for (int i = array.length; --i >= 0; ) {
        char[] subarray = array[i];
        for (int j = subarray.length; --j >= 0; ) if (subarray[j] == character) return true;
      }
      return false;
    }
  
    /**
     * Answers true if the array contains an occurrence of character, false otherwise. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    character = 'c'
     *    array = { ' b'  }
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    character = 'a'
     *    array = { ' a' , ' b' }
     *    result => true
     * </pre>
     * </ol>
     *
     * @param character the character to search
     * @param array the array in which the search is done
     * @return true if the array contains an occurrence of character, false otherwise.
     * @throws NullPointerException if array is null.
     */
    public static final boolean contains(char character, char[] array) {
      for (int i = array.length; --i >= 0; ) if (array[i] == character) return true;
      return false;
    }
  
    /**
     * Answers true if the array contains an occurrence of one of the characters, false otherwise.
     * <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    characters = { 'c', 'd' }
     *    array = { 'a', ' b'  }
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    characters = { 'c', 'd' }
     *    array = { 'a', ' b', 'c'  }
     *    result => true
     * </pre>
     * </ol>
     *
     * @param characters the characters to search
     * @param array the array in which the search is done
     * @return true if the array contains an occurrence of one of the characters, false otherwise.
     * @throws NullPointerException if array is null.
     * @since 3.1
     */
    public static final boolean contains(char[] characters, char[] array) {
      for (int i = array.length; --i >= 0; )
        for (int j = characters.length; --j >= 0; ) if (array[i] == characters[j]) return true;
      return false;
    }
  
    /**
     * Does the given array contain a char sequence that is equal to the give sequence?
     *
     * @param array
     * @param sequence
     * @return true if sequence is equal to an element in array
     * @since 3.14
     */
    public static boolean containsEqual(char[][] array, char[] sequence) {
      for (int i = 0; i < array.length; i++) {
        if (equals(array[i], sequence)) return true;
      }
      return false;
    }
  
    /**
     * Answers true if the two arrays are identical character by character, otherwise false. The
     * equality is case sensitive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { }
     *    second = null
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'a' }
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'A' }
     *    result => false
     * </pre>
     * </ol>
     *
     * @param first the first array
     * @param second the second array
     * @return true if the two arrays are identical character by character, otherwise false
     */
    public static final boolean equals(char[] first, char[] second) {
      return Arrays.equals(first, second);
    }
  
    /**
     * Answers a deep copy of the toCopy array.
     *
     * @param toCopy the array to copy
     * @return a deep copy of the toCopy array.
     */
    public static final char[][] deepCopy(char[][] toCopy) {
      int toCopyLength = toCopy.length;
      char[][] result = new char[toCopyLength][];
      for (int i = 0; i < toCopyLength; i++) {
        char[] toElement = toCopy[i];
        int toElementLength = toElement.length;
        char[] resultElement = new char[toElementLength];
        System.arraycopy(toElement, 0, resultElement, 0, toElementLength);
        result[i] = resultElement;
      }
      return result;
    }
  
    /**
     * Return true if array ends with the sequence of characters contained in toBeFound, otherwise
     * false. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b', 'c', 'd' }
     *    toBeFound = { 'b', 'c' }
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b', 'c' }
     *    toBeFound = { 'b', 'c' }
     *    result => true
     * </pre>
     * </ol>
     *
     * @param array the array to check
     * @param toBeFound the array to find
     * @return true if array ends with the sequence of characters contained in toBeFound, otherwise
     *     false.
     * @throws NullPointerException if array is null or toBeFound is null
     */
    public static final boolean endsWith(char[] array, char[] toBeFound) {
      int i = toBeFound.length;
      int j = array.length - i;
  
      if (j < 0) return false;
      while (--i >= 0) if (toBeFound[i] != array[i + j]) return false;
      return true;
    }
  
    /**
     * If isCaseSensite is true, answers true if the two arrays are identical character by character,
     * otherwise false. If it is false, answers true if the two arrays are identical character by
     * character without checking the case, otherwise false. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    isCaseSensitive = true
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { } }
     *    second = null
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { 'A' } }
     *    second = { { 'a' } }
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { 'A' } }
     *    second = { { 'a' } }
     *    isCaseSensitive = false
     *    result => true
     * </pre>
     * </ol>
     *
     * @param first the first array
     * @param second the second array
     * @param isCaseSensitive check whether or not the equality should be case sensitive
     * @return true if the two arrays are identical character by character according to the value of
     *     isCaseSensitive, otherwise false
     */
    public static final boolean equals(char[][] first, char[][] second, boolean isCaseSensitive) {
  
      if (isCaseSensitive) {
        return equals(first, second);
      }
      if (first == second) return true;
      if (first == null || second == null) return false;
      if (first.length != second.length) return false;
  
      for (int i = first.length; --i >= 0; ) if (!equals(first[i], second[i], false)) return false;
      return true;
    }
  
    /**
     * Answers true if the two arrays are identical character by character, otherwise false. The
     * equality is case sensitive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { } }
     *    second = null
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { 'a' } }
     *    second = { { 'a' } }
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { { 'A' } }
     *    second = { { 'a' } }
     *    result => false
     * </pre>
     * </ol>
     *
     * @param first the first array
     * @param second the second array
     * @return true if the two arrays are identical character by character, otherwise false
     */
    public static final boolean equals(char[][] first, char[][] second) {
      if (first == second) return true;
      if (first == null || second == null) return false;
      if (first.length != second.length) return false;
  
      for (int i = first.length; --i >= 0; ) if (!equals(first[i], second[i])) return false;
      return true;
    }
  
    /**
     * If isCaseSensite is true, answers true if the two arrays are identical character by character,
     * otherwise false. If it is false, answers true if the two arrays are identical character by
     * character without checking the case, otherwise false. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    isCaseSensitive = true
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { }
     *    second = null
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'A' }
     *    second = { 'a' }
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'A' }
     *    second = { 'a' }
     *    isCaseSensitive = false
     *    result => true
     * </pre>
     * </ol>
     *
     * @param first the first array
     * @param second the second array
     * @param isCaseSensitive check whether or not the equality should be case sensitive
     * @return true if the two arrays are identical character by character according to the value of
     *     isCaseSensitive, otherwise false
     */
    public static final boolean equals(char[] first, char[] second, boolean isCaseSensitive) {
  
      if (isCaseSensitive) {
        return equals(first, second);
      }
      if (first == second) return true;
      if (first == null || second == null) return false;
      if (first.length != second.length) return false;
  
      for (int i = first.length; --i >= 0; )
        if (ScannerHelper.toLowerCase(first[i]) != ScannerHelper.toLowerCase(second[i])) return false;
      return true;
    }
  
    /**
     * Answers true if the first array is identical character by character to a portion of the second
     * array delimited from position secondStart (inclusive) to secondEnd(exclusive), otherwise false.
     * The equality is case sensitive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    secondStart = 0
     *    secondEnd = 0
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { }
     *    second = null
     *    secondStart = 0
     *    secondEnd = 0
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'a' }
     *    secondStart = 0
     *    secondEnd = 1
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'A' }
     *    secondStart = 0
     *    secondEnd = 1
     *    result => false
     * </pre>
     * </ol>
     *
     * @param first the first array
     * @param second the second array
     * @param secondStart inclusive start position in the second array to compare
     * @param secondEnd exclusive end position in the second array to compare
     * @return true if the first array is identical character by character to fragment of second array
     *     ranging from secondStart to secondEnd-1, otherwise false
     * @since 3.0
     */
    public static final boolean equals(char[] first, char[] second, int secondStart, int secondEnd) {
      return equals(first, second, secondStart, secondEnd, true);
    }
  
    /**
     * Answers true if the first array is identical character by character to a portion of the second
     * array delimited from position secondStart (inclusive) to secondEnd(exclusive), otherwise false.
     * The equality could be either case sensitive or case insensitive according to the value of the
     * <code>isCaseSensitive</code> parameter.
     *
     * <p>For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    first = null
     *    second = null
     *    secondStart = 0
     *    secondEnd = 0
     *    isCaseSensitive = false
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { }
     *    second = null
     *    secondStart = 0
     *    secondEnd = 0
     *    isCaseSensitive = false
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'a' }
     *    secondStart = 0
     *    secondEnd = 1
     *    isCaseSensitive = true
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'A' }
     *    secondStart = 0
     *    secondEnd = 1
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    first = { 'a' }
     *    second = { 'A' }
     *    secondStart = 0
     *    secondEnd = 1
     *    isCaseSensitive = false
     *    result => true
     * </pre>
     * </ol>
     *
     * @param first the first array
     * @param second the second array
     * @param secondStart inclusive start position in the second array to compare
     * @param secondEnd exclusive end position in the second array to compare
     * @param isCaseSensitive check whether or not the equality should be case sensitive
     * @return true if the first array is identical character by character to fragment of second array
     *     ranging from secondStart to secondEnd-1, otherwise false
     * @since 3.2
     */
    public static final boolean equals(
        char[] first, char[] second, int secondStart, int secondEnd, boolean isCaseSensitive) {
      if (first == second) return true;
      if (first == null || second == null) return false;
      if (first.length != secondEnd - secondStart) return false;
      if (isCaseSensitive) {
        for (int i = first.length; --i >= 0; ) if (first[i] != second[i + secondStart]) return false;
      } else {
        for (int i = first.length; --i >= 0; )
          if (ScannerHelper.toLowerCase(first[i])
              != ScannerHelper.toLowerCase(second[i + secondStart])) return false;
      }
      return true;
    }
  
    /**
     * If isCaseSensite is true, the equality is case sensitive, otherwise it is case insensitive.
     *
     * <p>Answers true if the name contains the fragment at the starting index startIndex, otherwise
     * false. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    fragment = { 'b', 'c' , 'd' }
     *    name = { 'a', 'b', 'c' , 'd' }
     *    startIndex = 1
     *    isCaseSensitive = true
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    fragment = { 'b', 'c' , 'd' }
     *    name = { 'a', 'b', 'C' , 'd' }
     *    startIndex = 1
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    fragment = { 'b', 'c' , 'd' }
     *    name = { 'a', 'b', 'C' , 'd' }
     *    startIndex = 0
     *    isCaseSensitive = false
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    fragment = { 'b', 'c' , 'd' }
     *    name = { 'a', 'b'}
     *    startIndex = 0
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     * </ol>
     *
     * @param fragment the fragment to check
     * @param name the array to check
     * @param startIndex the starting index
     * @param isCaseSensitive check whether or not the equality should be case sensitive
     * @return true if the name contains the fragment at the starting index startIndex according to
     *     the value of isCaseSensitive, otherwise false.
     * @throws NullPointerException if fragment or name is null.
     */
    public static final boolean fragmentEquals(
        char[] fragment, char[] name, int startIndex, boolean isCaseSensitive) {
  
      int max = fragment.length;
      if (name.length < max + startIndex) return false;
      if (isCaseSensitive) {
        for (int i = max; --i >= 0; ) {
          // assumes the prefix is not larger than the name
          if (fragment[i] != name[i + startIndex]) {
            return false;
          }
        }
        return true;
      }
      for (int i = max; --i >= 0; ) {
        // assumes the prefix is not larger than the name
        if (ScannerHelper.toLowerCase(fragment[i])
            != ScannerHelper.toLowerCase(name[i + startIndex])) {
          return false;
        }
      }
      return true;
    }
  
    /**
     * Answers a hashcode for the array
     *
     * @param array the array for which a hashcode is required
     * @return the hashcode
     */
    public static final int hashCode(char[] array) {
      int hash = Arrays.hashCode(array);
      return hash & 0x7FFFFFFF;
    }
  
    /**
     * Answers true if c is a whitespace according to the JLS (&#92;u0009, &#92;u000a, &#92;u000c,
     * &#92;u000d, &#92;u0020), otherwise false. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    c = ' '
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    c = '&#92;u3000'
     *    result => false
     * </pre>
     * </ol>
     *
     * @param c the character to check
     * @return true if c is a whitespace according to the JLS, otherwise false.
     */
    public static boolean isWhitespace(char c) {
      return c < ScannerHelper.MAX_OBVIOUS
          && ((ScannerHelper.OBVIOUS_IDENT_CHAR_NATURES[c] & ScannerHelper.C_JLS_SPACE) != 0);
    }
  
    /**
     * Answers the first index in the array for which the corresponding character is equal to
     * toBeFound. Answers -1 if no occurrence of this character is found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'e'
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the character to search
     * @param array the array to be searched
     * @return the first index in the array for which the corresponding character is equal to
     *     toBeFound, -1 otherwise
     * @throws NullPointerException if array is null
     */
    public static final int indexOf(char toBeFound, char[] array) {
      return indexOf(toBeFound, array, 0);
    }
  
    /**
     * Answers the first index in the array for which the corresponding character is equal to
     * toBeFound starting the search at index start. Answers -1 if no occurrence of this character is
     * found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    start = 2
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    start = 3
     *    result => -1
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'e'
     *    array = { ' a', 'b', 'c', 'd' }
     *    start = 1
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the character to search
     * @param array the array to be searched
     * @param start the starting index
     * @return the first index in the array for which the corresponding character is equal to
     *     toBeFound, -1 otherwise
     * @throws NullPointerException if array is null
     * @throws ArrayIndexOutOfBoundsException if start is lower than 0
     */
    public static final int indexOf(char toBeFound, char[] array, int start) {
      for (int i = start; i < array.length; i++) if (toBeFound == array[i]) return i;
      return -1;
    }
  
    /**
     * Answers the first index in the array for which the toBeFound array is a matching subarray
     * following the case rule. Answers -1 if no match is found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = { 'c' }
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = { 'e' }
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the subarray to search
     * @param array the array to be searched
     * @param isCaseSensitive flag to know if the matching should be case sensitive
     * @return the first index in the array for which the toBeFound array is a matching subarray
     *     following the case rule, -1 otherwise
     * @throws NullPointerException if array is null or toBeFound is null
     * @since 3.2
     */
    public static final int indexOf(char[] toBeFound, char[] array, boolean isCaseSensitive) {
      return indexOf(toBeFound, array, isCaseSensitive, 0);
    }
  
    /**
     * Answers the first index in the array for which the toBeFound array is a matching subarray
     * following the case rule starting at the index start. Answers -1 if no match is found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = { 'c' }
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = { 'e' }
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the subarray to search
     * @param array the array to be searched
     * @param isCaseSensitive flag to know if the matching should be case sensitive
     * @param start the starting index
     * @return the first index in the array for which the toBeFound array is a matching subarray
     *     following the case rule starting at the index start, -1 otherwise
     * @throws NullPointerException if array is null or toBeFound is null
     * @since 3.2
     */
    public static final int indexOf(
        final char[] toBeFound, final char[] array, final boolean isCaseSensitive, final int start) {
      return indexOf(toBeFound, array, isCaseSensitive, start, array.length);
    }
  
    /**
     * Answers the first index in the array for which the toBeFound array is a matching subarray
     * following the case rule starting at the index start. Answers -1 if no match is found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = { 'c' }
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = { 'e' }
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the subarray to search
     * @param array the array to be searched
     * @param isCaseSensitive flag to know if the matching should be case sensitive
     * @param start the starting index (inclusive)
     * @param end the end index (exclusive)
     * @return the first index in the array for which the toBeFound array is a matching subarray
     *     following the case rule starting at the index start, -1 otherwise
     * @throws NullPointerException if array is null or toBeFound is null
     * @since 3.2
     */
    public static final int indexOf(
        final char[] toBeFound,
        final char[] array,
        final boolean isCaseSensitive,
        final int start,
        final int end) {
      final int arrayLength = end;
      final int toBeFoundLength = toBeFound.length;
      if (toBeFoundLength > arrayLength || start < 0) return -1;
      if (toBeFoundLength == 0) return 0;
      if (toBeFoundLength == arrayLength) {
        if (isCaseSensitive) {
          for (int i = start; i < arrayLength; i++) {
            if (array[i] != toBeFound[i]) return -1;
          }
          return 0;
        } else {
          for (int i = start; i < arrayLength; i++) {
            if (ScannerHelper.toLowerCase(array[i]) != ScannerHelper.toLowerCase(toBeFound[i]))
              return -1;
          }
          return 0;
        }
      }
      if (isCaseSensitive) {
        arrayLoop:
        for (int i = start, max = arrayLength - toBeFoundLength + 1; i < max; i++) {
          if (array[i] == toBeFound[0]) {
            for (int j = 1; j < toBeFoundLength; j++) {
              if (array[i + j] != toBeFound[j]) continue arrayLoop;
            }
            return i;
          }
        }
      } else {
        arrayLoop:
        for (int i = start, max = arrayLength - toBeFoundLength + 1; i < max; i++) {
          if (ScannerHelper.toLowerCase(array[i]) == ScannerHelper.toLowerCase(toBeFound[0])) {
            for (int j = 1; j < toBeFoundLength; j++) {
              if (ScannerHelper.toLowerCase(array[i + j]) != ScannerHelper.toLowerCase(toBeFound[j]))
                continue arrayLoop;
            }
            return i;
          }
        }
      }
      return -1;
    }
  
    /**
     * Answers the first index in the array for which the corresponding character is equal to
     * toBeFound starting the search at index start and before the ending index. Answers -1 if no
     * occurrence of this character is found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    start = 2
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    start = 3
     *    result => -1
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'e'
     *    array = { ' a', 'b', 'c', 'd' }
     *    start = 1
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the character to search
     * @param array the array to be searched
     * @param start the starting index (inclusive)
     * @param end the ending index (exclusive)
     * @return the first index in the array for which the corresponding character is equal to
     *     toBeFound, -1 otherwise
     * @throws NullPointerException if array is null
     * @throws ArrayIndexOutOfBoundsException if start is lower than 0 or ending greater than array
     *     length
     * @since 3.2
     */
    public static final int indexOf(char toBeFound, char[] array, int start, int end) {
      for (int i = start; i < end; i++) if (toBeFound == array[i]) return i;
      return -1;
    }
  
    /**
     * Answers the last index in the array for which the corresponding character is equal to toBeFound
     * stopping at the index startIndex. Answers -1 if no occurrence of this character is found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    startIndex = 2
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd', 'e' }
     *    startIndex = 3
     *    result => -1
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'e'
     *    array = { ' a', 'b', 'c', 'd' }
     *    startIndex = 0
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the character to search
     * @param array the array to be searched
     * @param startIndex the stopping index
     * @return the last index in the array for which the corresponding character is equal to toBeFound
     *     stopping at the index startIndex, -1 otherwise
     * @throws NullPointerException if array is null
     * @throws ArrayIndexOutOfBoundsException if startIndex is lower than 0
     */
    public static final int lastIndexOf(char toBeFound, char[] array, int startIndex) {
      for (int i = array.length; --i >= startIndex; ) if (toBeFound == array[i]) return i;
      return -1;
    }
  
    /**
     * Answers the last index in the array for which the corresponding character is equal to toBeFound
     * starting from endIndex to startIndex. Answers -1 if no occurrence of this character is found.
     * <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' }
     *    startIndex = 2
     *    endIndex = 2
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd', 'e' }
     *    startIndex = 3
     *    endIndex = 4
     *    result => -1
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'e'
     *    array = { ' a', 'b', 'c', 'd' }
     *    startIndex = 0
     *    endIndex = 3
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the character to search
     * @param array the array to be searched
     * @param startIndex the stopping index
     * @param endIndex the starting index
     * @return the last index in the array for which the corresponding character is equal to toBeFound
     *     starting from endIndex to startIndex, -1 otherwise
     * @throws NullPointerException if array is null
     * @throws ArrayIndexOutOfBoundsException if endIndex is greater or equals to array length or
     *     starting is lower than 0
     */
    public static final int lastIndexOf(char toBeFound, char[] array, int startIndex, int endIndex) {
      for (int i = endIndex; --i >= startIndex; ) if (toBeFound == array[i]) return i;
      return -1;
    }
  
    /**
     * Answers the last portion of a name given a separator. <br>
     * <br>
     * For example,
     *
     * <pre>
     * 	lastSegment("java.lang.Object".toCharArray(),'.') --> Object
     * </pre>
     *
     * @param array the array
     * @param separator the given separator
     * @return the last portion of a name given a separator
     * @throws NullPointerException if array is null
     */
    public static final char[] lastSegment(char[] array, char separator) {
      int pos = lastIndexOf(separator, array);
      if (pos < 0) return array;
      return subarray(array, pos + 1, array.length);
    }
  
    /**
     * Answers the last index in the array for which the corresponding character is equal to toBeFound
     * starting from the end of the array. Answers -1 if no occurrence of this character is found.
     * <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { ' a', 'b', 'c', 'd' , 'c', 'e' }
     *    result => 4
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'e'
     *    array = { ' a', 'b', 'c', 'd' }
     *    result => -1
     * </pre>
     * </ol>
     *
     * @param toBeFound the character to search
     * @param array the array to be searched
     * @return the last index in the array for which the corresponding character is equal to toBeFound
     *     starting from the end of the array, -1 otherwise
     * @throws NullPointerException if array is null
     */
    public static final int lastIndexOf(char toBeFound, char[] array) {
      for (int i = array.length; --i >= 0; ) if (toBeFound == array[i]) return i;
      return -1;
    }
  
    /**
     * Answers a new array which is a copy of the given array starting at the given start and ending
     * at the given end. The given start is inclusive and the given end is exclusive. Answers null if
     * start is greater than end, if start is lower than 0 or if end is greater than the length of the
     * given array. If end equals -1, it is converted to the array length. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b' }
     *    start = 0
     *    end = 1
     *    result => { 'a' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'b' }
     *    start = 0
     *    end = -1
     *    result => { 'a' , 'b' }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param start the given starting index
     * @param end the given ending index
     * @return a new array which is a copy of the given array starting at the given start and ending
     *     at the given end
     * @throws NullPointerException if the given array is null
     */
    public static final char[] subarray(char[] array, int start, int end) {
      if (end == -1) end = array.length;
      if (start > end) return null;
      if (start < 0) return null;
      if (end > array.length) return null;
  
      char[] result = new char[end - start];
      System.arraycopy(array, start, result, 0, end - start);
      return result;
    }
  
    /**
     * Answers true if the pattern matches the given name, false otherwise. This char[] pattern
     * matching accepts wild-cards '*' and '?'.
     *
     * <p>When not case sensitive, the pattern is assumed to already be lowercased, the name will be
     * lowercased character per character as comparing.<br>
     * If name is null, the answer is false.<br>
     * If pattern is null, the answer is true if name is not null. For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    pattern = { '?', 'b', '*' }
     *    name = { 'a', 'b', 'c' , 'd' }
     *    isCaseSensitive = true
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    pattern = { '?', 'b', '?' }
     *    name = { 'a', 'b', 'c' , 'd' }
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     *   <li>
     *       <pre>
     *    pattern = { 'b', '*' }
     *    name = { 'a', 'b', 'c' , 'd' }
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     * </ol>
     *
     * @param pattern the given pattern
     * @param name the given name
     * @param isCaseSensitive flag to know whether or not the matching should be case sensitive
     * @return true if the pattern matches the given name, false otherwise
     */
    public static final boolean match(char[] pattern, char[] name, boolean isCaseSensitive) {
  
      if (name == null) return false; // null name cannot match
      if (pattern == null) return true; // null pattern is equivalent to '*'
  
      return match(pattern, 0, pattern.length, name, 0, name.length, isCaseSensitive);
    }
  
    /**
     * Answers true if a sub-pattern matches the subpart of the given name, false otherwise. char[]
     * pattern matching, accepting wild-cards '*' and '?'. Can match only subset of name/pattern. end
     * positions are non-inclusive. The subpattern is defined by the patternStart and pattternEnd
     * positions. When not case sensitive, the pattern is assumed to already be lowercased, the name
     * will be lowercased character per character as comparing. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    pattern = { '?', 'b', '*' }
     *    patternStart = 1
     *    patternEnd = 3
     *    name = { 'a', 'b', 'c' , 'd' }
     *    nameStart = 1
     *    nameEnd = 4
     *    isCaseSensitive = true
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    pattern = { '?', 'b', '*' }
     *    patternStart = 1
     *    patternEnd = 2
     *    name = { 'a', 'b', 'c' , 'd' }
     *    nameStart = 1
     *    nameEnd = 4
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     * </ol>
     *
     * @param pattern the given pattern
     * @param patternStart the given pattern start
     * @param patternEnd the given pattern end
     * @param name the given name
     * @param nameStart the given name start
     * @param nameEnd the given name end
     * @param isCaseSensitive flag to know if the matching should be case sensitive
     * @return true if a sub-pattern matches the subpart of the given name, false otherwise
     */
    public static final boolean match(
        char[] pattern,
        int patternStart,
        int patternEnd,
        char[] name,
        int nameStart,
        int nameEnd,
        boolean isCaseSensitive) {
  
      if (name == null) return false; // null name cannot match
      if (pattern == null) return true; // null pattern is equivalent to '*'
      int iPattern = patternStart;
      int iName = nameStart;
  
      if (patternEnd < 0) patternEnd = pattern.length;
      if (nameEnd < 0) nameEnd = name.length;
  
      /* check first segment */
      char patternChar = 0;
      while (true) {
        if (iPattern == patternEnd) {
          if (iName == nameEnd) return true; // the chars match
          return false; // pattern has ended but not the name, no match
        }
        if ((patternChar = pattern[iPattern]) == '*') {
          break;
        }
        if (iName == nameEnd) {
          return false; // name has ended but not the pattern
        }
        if (patternChar != (isCaseSensitive ? name[iName] : ScannerHelper.toLowerCase(name[iName]))
            && patternChar != '?') {
          return false;
        }
        iName++;
        iPattern++;
      }
      /* check sequence of star+segment */
      int segmentStart;
      if (patternChar == '*') {
        segmentStart = ++iPattern; // skip star
      } else {
        segmentStart = 0; // force iName check
      }
      int prefixStart = iName;
      checkSegment:
      while (iName < nameEnd) {
        if (iPattern == patternEnd) {
          iPattern = segmentStart; // mismatch - restart current segment
          iName = ++prefixStart;
          continue checkSegment;
        }
        /* segment is ending */
        if ((patternChar = pattern[iPattern]) == '*') {
          segmentStart = ++iPattern; // skip start
          if (segmentStart == patternEnd) {
            return true;
          }
          prefixStart = iName;
          continue checkSegment;
        }
        /* check current name character */
        if ((isCaseSensitive ? name[iName] : ScannerHelper.toLowerCase(name[iName])) != patternChar
            && patternChar != '?') {
          iPattern = segmentStart; // mismatch - restart current segment
          iName = ++prefixStart;
          continue checkSegment;
        }
        iName++;
        iPattern++;
      }
  
      return (segmentStart == patternEnd)
          || (iName == nameEnd && iPattern == patternEnd)
          || (iPattern == patternEnd - 1 && pattern[iPattern] == '*');
    }
  
    /**
     * Answers true if the pattern matches the filepath using the pathSepatator, false otherwise.
     *
     * <p>Path char[] pattern matching, accepting wild-cards '**', '*' and '?' (using Ant directory
     * tasks conventions, also see
     * "http://jakarta.apache.org/ant/manual/dirtasks.html#defaultexcludes"). Path pattern matching is
     * enhancing regular pattern matching in supporting extra rule where '**' represent any folder
     * combination. Special rule: - foo\ is equivalent to foo\** When not case sensitive, the pattern
     * is assumed to already be lowercased, the name will be lowercased character per character as
     * comparing.
     *
     * @param pattern the given pattern
     * @param filepath the given path
     * @param isCaseSensitive to find out whether or not the matching should be case sensitive
     * @param pathSeparator the given path separator
     * @return true if the pattern matches the filepath using the pathSepatator, false otherwise
     */
    public static final boolean pathMatch(
        char[] pattern, char[] filepath, boolean isCaseSensitive, char pathSeparator) {
  
      if (filepath == null) return false; // null name cannot match
      if (pattern == null) return true; // null pattern is equivalent to '*'
  
      // offsets inside pattern
      int pSegmentStart = pattern[0] == pathSeparator ? 1 : 0;
      int pLength = pattern.length;
      int pSegmentEnd = CharOperation.indexOf(pathSeparator, pattern, pSegmentStart + 1);
      if (pSegmentEnd < 0) pSegmentEnd = pLength;
  
      // special case: pattern foo\ is equivalent to foo\**
      boolean freeTrailingDoubleStar = pattern[pLength - 1] == pathSeparator;
  
      // offsets inside filepath
      int fSegmentStart, fLength = filepath.length;
      if (filepath[0] != pathSeparator) {
        fSegmentStart = 0;
      } else {
        fSegmentStart = 1;
      }
      if (fSegmentStart != pSegmentStart) {
        return false; // both must start with a separator or none.
      }
      int fSegmentEnd = CharOperation.indexOf(pathSeparator, filepath, fSegmentStart + 1);
      if (fSegmentEnd < 0) fSegmentEnd = fLength;
  
      // first segments
      while (pSegmentStart < pLength
          && !(pSegmentEnd == pLength && freeTrailingDoubleStar
              || (pSegmentEnd == pSegmentStart + 2
                  && pattern[pSegmentStart] == '*'
                  && pattern[pSegmentStart + 1] == '*'))) {
  
        if (fSegmentStart >= fLength) return false;
        if (!CharOperation.match(
            pattern,
            pSegmentStart,
            pSegmentEnd,
            filepath,
            fSegmentStart,
            fSegmentEnd,
            isCaseSensitive)) {
          return false;
        }
  
        // jump to next segment
        pSegmentEnd = CharOperation.indexOf(pathSeparator, pattern, pSegmentStart = pSegmentEnd + 1);
        // skip separator
        if (pSegmentEnd < 0) pSegmentEnd = pLength;
  
        fSegmentEnd = CharOperation.indexOf(pathSeparator, filepath, fSegmentStart = fSegmentEnd + 1);
        // skip separator
        if (fSegmentEnd < 0) fSegmentEnd = fLength;
      }
  
      /* check sequence of doubleStar+segment */
      int pSegmentRestart;
      if ((pSegmentStart >= pLength && freeTrailingDoubleStar)
          || (pSegmentEnd == pSegmentStart + 2
              && pattern[pSegmentStart] == '*'
              && pattern[pSegmentStart + 1] == '*')) {
        pSegmentEnd = CharOperation.indexOf(pathSeparator, pattern, pSegmentStart = pSegmentEnd + 1);
        // skip separator
        if (pSegmentEnd < 0) pSegmentEnd = pLength;
        pSegmentRestart = pSegmentStart;
      } else {
        if (pSegmentStart >= pLength)
          return fSegmentStart >= fLength; // true if filepath is done too.
        pSegmentRestart = 0; // force fSegmentStart check
      }
      int fSegmentRestart = fSegmentStart;
      checkSegment:
      while (fSegmentStart < fLength) {
  
        if (pSegmentStart >= pLength) {
          if (freeTrailingDoubleStar) return true;
          // mismatch - restart current path segment
          pSegmentEnd =
              CharOperation.indexOf(pathSeparator, pattern, pSegmentStart = pSegmentRestart);
          if (pSegmentEnd < 0) pSegmentEnd = pLength;
  
          fSegmentRestart = CharOperation.indexOf(pathSeparator, filepath, fSegmentRestart + 1);
          // skip separator
          if (fSegmentRestart < 0) {
            fSegmentRestart = fLength;
          } else {
            fSegmentRestart++;
          }
          fSegmentEnd =
              CharOperation.indexOf(pathSeparator, filepath, fSegmentStart = fSegmentRestart);
          if (fSegmentEnd < 0) fSegmentEnd = fLength;
          continue checkSegment;
        }
  
        /* path segment is ending */
        if (pSegmentEnd == pSegmentStart + 2
            && pattern[pSegmentStart] == '*'
            && pattern[pSegmentStart + 1] == '*') {
          pSegmentEnd =
              CharOperation.indexOf(pathSeparator, pattern, pSegmentStart = pSegmentEnd + 1);
          // skip separator
          if (pSegmentEnd < 0) pSegmentEnd = pLength;
          pSegmentRestart = pSegmentStart;
          fSegmentRestart = fSegmentStart;
          if (pSegmentStart >= pLength) return true;
          continue checkSegment;
        }
        /* chech current path segment */
        if (!CharOperation.match(
            pattern,
            pSegmentStart,
            pSegmentEnd,
            filepath,
            fSegmentStart,
            fSegmentEnd,
            isCaseSensitive)) {
          // mismatch - restart current path segment
          pSegmentEnd =
              CharOperation.indexOf(pathSeparator, pattern, pSegmentStart = pSegmentRestart);
          if (pSegmentEnd < 0) pSegmentEnd = pLength;
  
          fSegmentRestart = CharOperation.indexOf(pathSeparator, filepath, fSegmentRestart + 1);
          // skip separator
          if (fSegmentRestart < 0) {
            fSegmentRestart = fLength;
          } else {
            fSegmentRestart++;
          }
          fSegmentEnd =
              CharOperation.indexOf(pathSeparator, filepath, fSegmentStart = fSegmentRestart);
          if (fSegmentEnd < 0) fSegmentEnd = fLength;
          continue checkSegment;
        }
        // jump to next segment
        pSegmentEnd = CharOperation.indexOf(pathSeparator, pattern, pSegmentStart = pSegmentEnd + 1);
        // skip separator
        if (pSegmentEnd < 0) pSegmentEnd = pLength;
  
        fSegmentEnd = CharOperation.indexOf(pathSeparator, filepath, fSegmentStart = fSegmentEnd + 1);
        // skip separator
        if (fSegmentEnd < 0) fSegmentEnd = fLength;
      }
  
      return (pSegmentRestart >= pSegmentEnd)
          || (fSegmentStart >= fLength && pSegmentStart >= pLength)
          || (pSegmentStart == pLength - 2
              && pattern[pSegmentStart] == '*'
              && pattern[pSegmentStart + 1] == '*')
          || (pSegmentStart == pLength && freeTrailingDoubleStar);
    }
  
    /**
     * Answers the number of occurrences of the given character in the given array, 0 if any. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'b'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => 3
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => 0
     * </pre>
     * </ol>
     *
     * @param toBeFound the given character
     * @param array the given array
     * @return the number of occurrences of the given character in the given array, 0 if any
     * @throws NullPointerException if array is null
     */
    public static final int occurencesOf(char toBeFound, char[] array) {
      int count = 0;
      for (int i = 0; i < array.length; i++) if (toBeFound == array[i]) count++;
      return count;
    }
  
    /**
     * Answers the number of occurrences of the given character in the given array starting at the
     * given index, 0 if any. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    toBeFound = 'b'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    start = 2
     *    result => 2
     * </pre>
     *   <li>
     *       <pre>
     *    toBeFound = 'c'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    start = 0
     *    result => 0
     * </pre>
     * </ol>
     *
     * @param toBeFound the given character
     * @param array the given array
     * @param start the given index
     * @return the number of occurrences of the given character in the given array, 0 if any
     * @throws NullPointerException if array is null
     * @throws ArrayIndexOutOfBoundsException if start is lower than 0
     */
    public static final int occurencesOf(char toBeFound, char[] array, int start) {
      int count = 0;
      for (int i = start; i < array.length; i++) if (toBeFound == array[i]) count++;
      return count;
    }
  
    /**
     * Return the int value represented by the designated subpart of array. The calculation of the
     * result for single-digit positive integers is optimized in time.
     *
     * @param array the array within which the int value is to be parsed
     * @param start first character of the int value in array
     * @param length length of the int value in array
     * @return the int value of a subpart of array
     * @throws NumberFormatException if the designated subpart of array does not parse to an int
     * @since 3.4
     */
    public static final int parseInt(char[] array, int start, int length)
        throws NumberFormatException {
      if (length == 1) {
        int result = array[start] - '0';
        if (result < 0 || result > 9) {
          throw new NumberFormatException("invalid digit"); // $NON-NLS-1$
        }
        return result;
      } else {
        return Integer.parseInt(new String(array, start, length));
      }
    }
  
    /**
     * Answers true if the given name starts with the given prefix, false otherwise. The comparison is
     * case sensitive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    prefix = { 'a' , 'b' }
     *    name = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    prefix = { 'a' , 'c' }
     *    name = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => false
     * </pre>
     * </ol>
     *
     * @param prefix the given prefix
     * @param name the given name
     * @return true if the given name starts with the given prefix, false otherwise
     * @throws NullPointerException if the given name is null or if the given prefix is null
     */
    public static final boolean prefixEquals(char[] prefix, char[] name) {
  
      int max = prefix.length;
      if (name.length < max) {
        return false;
      }
      for (int i = max; --i >= 0; ) {
        // assumes the prefix is not larger than the name
        if (prefix[i] != name[i]) {
          return false;
        }
      }
      return true;
    }
  
    /**
     * Answers true if the given name starts with the given prefix, false otherwise. isCaseSensitive
     * is used to find out whether or not the comparison should be case sensitive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    prefix = { 'a' , 'B' }
     *    name = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    isCaseSensitive = false
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    prefix = { 'a' , 'B' }
     *    name = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     * </ol>
     *
     * @param prefix the given prefix
     * @param name the given name
     * @param isCaseSensitive to find out whether or not the comparison should be case sensitive
     * @return true if the given name starts with the given prefix, false otherwise
     * @throws NullPointerException if the given name is null or if the given prefix is null
     */
    public static final boolean prefixEquals(char[] prefix, char[] name, boolean isCaseSensitive) {
      return prefixEquals(prefix, name, isCaseSensitive, 0);
    }
  
    /**
     * Answers true if the given name, starting from the given index, starts with the given prefix,
     * false otherwise. isCaseSensitive is used to find out whether or not the comparison should be
     * case sensitive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    prefix = { 'a' , 'B' }
     *    name = { 'c', 'd', 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    startIndex = 2
     *    isCaseSensitive = false
     *    result => true
     * </pre>
     *   <li>
     *       <pre>
     *    prefix = { 'a' , 'B' }
     *    name = { 'c', 'd', 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    startIndex = 2
     *    isCaseSensitive = true
     *    result => false
     * </pre>
     * </ol>
     *
     * @param prefix the given prefix
     * @param name the given name
     * @param isCaseSensitive to find out whether or not the comparison should be case sensitive
     * @param startIndex index from which the prefix should be searched in the name
     * @return true if the given name starts with the given prefix, false otherwise
     * @throws NullPointerException if the given name is null or if the given prefix is null
     * @since 3.7
     */
    public static final boolean prefixEquals(
        char[] prefix, char[] name, boolean isCaseSensitive, int startIndex) {
  
      int max = prefix.length;
      if (name.length - startIndex < max) return false;
      if (isCaseSensitive) {
        for (int i = max; --i >= 0; ) {
          // assumes the prefix is not larger than the name
          if (prefix[i] != name[startIndex + i]) {
            return false;
          }
        }
        return true;
      }
  
      for (int i = max; --i >= 0; ) {
        // assumes the prefix is not larger than the name
        if (ScannerHelper.toLowerCase(prefix[i]) != ScannerHelper.toLowerCase(name[startIndex + i])) {
          return false;
        }
      }
      return true;
    }
  
    /**
     * Answers a new array removing a given character. Answers the given array if there is no
     * occurrence of the character to remove. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'c', 'b', 'a' }
     *    toBeRemoved = 'b'
     *    return { 'a' , 'c', 'a' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeRemoved = 'c'
     *    return array
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param toBeRemoved the character to be removed
     * @return a new array removing given character
     * @since 3.2
     */
    public static final char[] remove(char[] array, char toBeRemoved) {
  
      if (array == null) return null;
      int length = array.length;
      if (length == 0) return array;
      char[] result = null;
      int count = 0;
      for (int i = 0; i < length; i++) {
        char c = array[i];
        if (c == toBeRemoved) {
          if (result == null) {
            result = new char[length];
            System.arraycopy(array, 0, result, 0, i);
            count = i;
          }
        } else if (result != null) {
          result[count++] = c;
        }
      }
      if (result == null) return array;
      System.arraycopy(result, 0, result = new char[count], 0, count);
      return result;
    }
  
    /**
     * Replace all occurrence of the character to be replaced with the replacement character in the
     * given array. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeReplaced = 'b'
     *    replacementChar = 'a'
     *    result => No returned value, but array is now equals to { 'a' , 'a', 'a', 'a', 'a', 'a' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeReplaced = 'c'
     *    replacementChar = 'a'
     *    result => No returned value, but array is now equals to { 'a' , 'b', 'b', 'a', 'b', 'a' }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param toBeReplaced the character to be replaced
     * @param replacementChar the replacement character
     * @throws NullPointerException if the given array is null
     */
    public static final void replace(char[] array, char toBeReplaced, char replacementChar) {
      if (toBeReplaced != replacementChar) {
        for (int i = 0, max = array.length; i < max; i++) {
          if (array[i] == toBeReplaced) array[i] = replacementChar;
        }
      }
    }
  
    /**
     * Replace all occurrences of characters to be replaced with the replacement character in the
     * given array. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'c', 'a', 'b', 'c', 'a' }
     *    toBeReplaced = { 'b', 'c' }
     *    replacementChar = 'a'
     *    result => No returned value, but array is now equals to { 'a' , 'a', 'a', 'a', 'a', 'a', 'a', 'a' }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param toBeReplaced characters to be replaced
     * @param replacementChar the replacement character
     * @throws NullPointerException if arrays are null.
     * @since 3.1
     */
    public static final void replace(char[] array, char[] toBeReplaced, char replacementChar) {
      replace(array, toBeReplaced, replacementChar, 0, array.length);
    }
  
    /**
     * Replace all occurrences of characters to be replaced with the replacement character in the
     * given array from the start position (inclusive) to the end position (exclusive). <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'c', 'a', 'b', 'c', 'a' }
     *    toBeReplaced = { 'b', 'c' }
     *    replacementChar = 'a'
     *    start = 4
     *    end = 8
     *    result => No returned value, but array is now equals to { 'a' , 'b', 'b', 'c', 'a', 'a', 'a', 'a' }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param toBeReplaced characters to be replaced
     * @param replacementChar the replacement character
     * @param start the given start position (inclusive)
     * @param end the given end position (exclusive)
     * @throws NullPointerException if arrays are null.
     * @since 3.2
     */
    public static final void replace(
        char[] array, char[] toBeReplaced, char replacementChar, int start, int end) {
      for (int i = end; --i >= start; )
        for (int j = toBeReplaced.length; --j >= 0; )
          if (array[i] == toBeReplaced[j]) array[i] = replacementChar;
    }
  
    /**
     * Answers a new array of characters with substitutions. No side-effect is operated on the
     * original array, in case no substitution happened, then the result is the same as the original
     * one. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeReplaced = { 'b' }
     *    replacementChar = { 'a', 'a' }
     *    result => { 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeReplaced = { 'c' }
     *    replacementChar = { 'a' }
     *    result => { 'a' , 'b', 'b', 'a', 'b', 'a' }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param toBeReplaced characters to be replaced
     * @param replacementChars the replacement characters
     * @return a new array of characters with substitutions or the given array if none
     * @throws NullPointerException if the given array is null
     */
    public static final char[] replace(char[] array, char[] toBeReplaced, char[] replacementChars) {
  
      int max = array.length;
      int replacedLength = toBeReplaced.length;
      int replacementLength = replacementChars.length;
  
      int[] starts = new int[5];
      int occurrenceCount = 0;
  
      if (!equals(toBeReplaced, replacementChars)) {
  
        next:
        for (int i = 0; i < max; ) {
          int index = indexOf(toBeReplaced, array, true, i);
          if (index == -1) {
            i++;
            continue next;
          }
          if (occurrenceCount == starts.length) {
            System.arraycopy(starts, 0, starts = new int[occurrenceCount * 2], 0, occurrenceCount);
          }
          starts[occurrenceCount++] = index;
          i = index + replacedLength;
        }
      }
      if (occurrenceCount == 0) return array;
      char[] result = new char[max + occurrenceCount * (replacementLength - replacedLength)];
      int inStart = 0, outStart = 0;
      for (int i = 0; i < occurrenceCount; i++) {
        int offset = starts[i] - inStart;
        System.arraycopy(array, inStart, result, outStart, offset);
        inStart += offset;
        outStart += offset;
        System.arraycopy(replacementChars, 0, result, outStart, replacementLength);
        inStart += replacedLength;
        outStart += replacementLength;
      }
      System.arraycopy(array, inStart, result, outStart, max - inStart);
      return result;
    }
  
    /**
     * Replace all occurrence of the character to be replaced with the replacement character in a copy
     * of the given array. Returns the given array if no occurrences of the character to be replaced
     * are found. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeReplaced = 'b'
     *    replacementChar = 'a'
     *    result => A new array that is equals to { 'a' , 'a', 'a', 'a', 'a', 'a' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    toBeReplaced = 'c'
     *    replacementChar = 'a'
     *    result => The original array that remains unchanged.
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param toBeReplaced the character to be replaced
     * @param replacementChar the replacement character
     * @throws NullPointerException if the given array is null
     * @since 3.1
     */
    public static final char[] replaceOnCopy(char[] array, char toBeReplaced, char replacementChar) {
  
      char[] result = null;
      for (int i = 0, length = array.length; i < length; i++) {
        char c = array[i];
        if (c == toBeReplaced) {
          if (result == null) {
            result = new char[length];
            System.arraycopy(array, 0, result, 0, i);
          }
          result[i] = replacementChar;
        } else if (result != null) {
          result[i] = c;
        }
      }
      if (result == null) return array;
      return result;
    }
  
    /**
     * Return a new array which is the split of the given array using the given divider and trimming
     * each subarray to remove whitespaces equals to ' '. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    divider = 'b'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => { { 'a' }, {  }, { 'a' }, { 'a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    divider = 'c'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => { { 'a', 'b', 'b', 'a', 'b', 'a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    divider = 'b'
     *    array = { 'a' , ' ', 'b', 'b', 'a', 'b', 'a' }
     *    result => { { 'a' }, {  }, { 'a' }, { 'a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    divider = 'c'
     *    array = { ' ', ' ', 'a' , 'b', 'b', 'a', 'b', 'a', ' ' }
     *    result => { { 'a', 'b', 'b', 'a', 'b', 'a' } }
     * </pre>
     * </ol>
     *
     * @param divider the given divider
     * @param array the given array
     * @return a new array which is the split of the given array using the given divider and trimming
     *     each subarray to remove whitespaces equals to ' '
     */
    public static final char[][] splitAndTrimOn(char divider, char[] array) {
      int length = array == null ? 0 : array.length;
      if (length == 0) return NO_CHAR_CHAR;
  
      int wordCount = 1;
      for (int i = 0; i < length; i++) if (array[i] == divider) wordCount++;
      char[][] split = new char[wordCount][];
      int last = 0, currentWord = 0;
      for (int i = 0; i < length; i++) {
        if (array[i] == divider) {
          int start = last, end = i - 1;
          while (start < i && array[start] == ' ') start++;
          while (end > start && array[end] == ' ') end--;
          split[currentWord] = new char[end - start + 1];
          System.arraycopy(array, start, split[currentWord++], 0, end - start + 1);
          last = i + 1;
        }
      }
      int start = last, end = length - 1;
      while (start < length && array[start] == ' ') start++;
      while (end > start && array[end] == ' ') end--;
      split[currentWord] = new char[end - start + 1];
      System.arraycopy(array, start, split[currentWord++], 0, end - start + 1);
      return split;
    }
  
    /**
     * Return a new array which is the split of the given array using the given divider. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    divider = 'b'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => { { 'a' }, {  }, { 'a' }, { 'a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    divider = 'c'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    result => { { 'a', 'b', 'b', 'a', 'b', 'a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    divider = 'c'
     *    array = { ' ', ' ', 'a' , 'b', 'b', 'a', 'b', 'a', ' ' }
     *    result => { { ' ', 'a', 'b', 'b', 'a', 'b', 'a', ' ' } }
     * </pre>
     * </ol>
     *
     * @param divider the given divider
     * @param array the given array
     * @return a new array which is the split of the given array using the given divider
     */
    public static final char[][] splitOn(char divider, char[] array) {
      int length = array == null ? 0 : array.length;
      if (length == 0) return NO_CHAR_CHAR;
  
      int wordCount = 1;
      for (int i = 0; i < length; i++) if (array[i] == divider) wordCount++;
      char[][] split = new char[wordCount][];
      int last = 0, currentWord = 0;
      for (int i = 0; i < length; i++) {
        if (array[i] == divider) {
          split[currentWord] = new char[i - last];
          System.arraycopy(array, last, split[currentWord++], 0, i - last);
          last = i + 1;
        }
      }
      split[currentWord] = new char[length - last];
      System.arraycopy(array, last, split[currentWord], 0, length - last);
      return split;
    }
  
    /**
     * Return a new array which is the split of the given array using the given divider ignoring the
     * text between (possibly nested) openEncl and closingEncl. If there are no openEncl in the code
     * this is identical to {@link CharOperation#splitOn(char, char[], int, int)}. The given end is
     * exclusive and the given start is inclusive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    divider = ','
     *    array = { 'A' , '<', 'B', ',', 'C', '>', ',', 'D' }
     *    start = 0
     *    end = 8
     *    result => { {  'A' , '<', 'B', ',', 'C', '>'}, { 'D' }}
     * </pre>
     * </ol>
     *
     * @param divider the given divider
     * @param openEncl the opening enclosure
     * @param closeEncl the closing enclosure
     * @param array the given array
     * @param start the given starting index
     * @param end the given ending index
     * @return a new array which is the split of the given array using the given divider
     * @throws ArrayIndexOutOfBoundsException if start is lower than 0 or end is greater than the
     *     array length
     * @since 3.12
     */
    public static final char[][] splitOnWithEnclosures(
        char divider, char openEncl, char closeEncl, char[] array, int start, int end) {
      int length = array == null ? 0 : array.length;
      if (length == 0 || start > end) return NO_CHAR_CHAR;
  
      int wordCount = 1;
      int enclCount = 0;
      for (int i = start; i < end; i++) {
        if (array[i] == openEncl) enclCount++;
        else if (array[i] == divider) wordCount++;
      }
      if (enclCount == 0) return CharOperation.splitOn(divider, array, start, end);
  
      int nesting = 0;
      if (openEncl == divider || closeEncl == divider) {
        // divider should be distinct
        return CharOperation.NO_CHAR_CHAR;
      }
  
      int[][] splitOffsets = new int[wordCount][2]; // maximum
      int last = start, currentWord = 0, prevOffset = start;
      for (int i = start; i < end; i++) {
        if (array[i] == openEncl) {
          ++nesting;
          continue;
        }
        if (array[i] == closeEncl) {
          if (nesting > 0) --nesting;
          continue;
        }
        if (array[i] == divider && nesting == 0) {
          splitOffsets[currentWord][0] = prevOffset;
          last = splitOffsets[currentWord++][1] = i;
          prevOffset = last + 1;
        }
      }
      if (last < end - 1) {
        splitOffsets[currentWord][0] = prevOffset;
        splitOffsets[currentWord++][1] = end;
      }
      char[][] split = new char[currentWord][];
      for (int i = 0; i < currentWord; ++i) {
        int sStart = splitOffsets[i][0];
        int sEnd = splitOffsets[i][1];
        int size = sEnd - sStart;
        split[i] = new char[size];
        System.arraycopy(array, sStart, split[i], 0, size);
      }
      return split;
    }
  
    /**
     * Return a new array which is the split of the given array using the given divider. The given end
     * is exclusive and the given start is inclusive. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    divider = 'b'
     *    array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
     *    start = 2
     *    end = 5
     *    result => { {  }, { 'a' }, {  } }
     * </pre>
     * </ol>
     *
     * @param divider the given divider
     * @param array the given array
     * @param start the given starting index
     * @param end the given ending index
     * @return a new array which is the split of the given array using the given divider
     * @throws ArrayIndexOutOfBoundsException if start is lower than 0 or end is greater than the
     *     array length
     */
    public static final char[][] splitOn(char divider, char[] array, int start, int end) {
      int length = array == null ? 0 : array.length;
      if (length == 0 || start > end) return NO_CHAR_CHAR;
  
      int wordCount = 1;
      for (int i = start; i < end; i++) if (array[i] == divider) wordCount++;
      char[][] split = new char[wordCount][];
      int last = start, currentWord = 0;
      for (int i = start; i < end; i++) {
        if (array[i] == divider) {
          split[currentWord] = new char[i - last];
          System.arraycopy(array, last, split[currentWord++], 0, i - last);
          last = i + 1;
        }
      }
      split[currentWord] = new char[end - last];
      System.arraycopy(array, last, split[currentWord], 0, end - last);
      return split;
    }
  
    /**
     * Answers a new array which is a copy of the given array starting at the given start and ending
     * at the given end. The given start is inclusive and the given end is exclusive. Answers null if
     * start is greater than end, if start is lower than 0 or if end is greater than the length of the
     * given array. If end equals -1, it is converted to the array length. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { { 'a' } , { 'b' } }
     *    start = 0
     *    end = 1
     *    result => { { 'a' } }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { { 'a' } , { 'b' } }
     *    start = 0
     *    end = -1
     *    result => { { 'a' }, { 'b' } }
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @param start the given starting index
     * @param end the given ending index
     * @return a new array which is a copy of the given array starting at the given start and ending
     *     at the given end
     * @throws NullPointerException if the given array is null
     */
    public static final char[][] subarray(char[][] array, int start, int end) {
      if (end == -1) end = array.length;
      if (start > end) return null;
      if (start < 0) return null;
      if (end > array.length) return null;
  
      char[][] result = new char[end - start][];
      System.arraycopy(array, start, result, 0, end - start);
      return result;
    }
  
    /**
     * Answers the result of a char[] conversion to lowercase. Answers null if the given chars array
     * is null. <br>
     * NOTE: If no conversion was necessary, then answers back the argument one. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    chars = { 'a' , 'b' }
     *    result => { 'a' , 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'A', 'b' }
     *    result => { 'a' , 'b' }
     * </pre>
     * </ol>
     *
     * @param chars the chars to convert
     * @return the result of a char[] conversion to lowercase
     */
    public static final char[] toLowerCase(char[] chars) {
      if (chars == null) return null;
      int length = chars.length;
      char[] lowerChars = null;
      for (int i = 0; i < length; i++) {
        char c = chars[i];
        char lc = ScannerHelper.toLowerCase(c);
        if ((c != lc) || (lowerChars != null)) {
          if (lowerChars == null) {
            System.arraycopy(chars, 0, lowerChars = new char[length], 0, i);
          }
          lowerChars[i] = lc;
        }
      }
      return lowerChars == null ? chars : lowerChars;
    }
  
    /**
     * Answers the result of a char[] conversion to uppercase. Answers null if the given chars array
     * is null. <br>
     * NOTE: If no conversion was necessary, then answers back the argument one. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    chars = { 'A' , 'B' }
     *    result => { 'A' , 'B' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'a', 'B' }
     *    result => { 'A' , 'B' }
     * </pre>
     * </ol>
     *
     * @param chars the chars to convert
     * @return the result of a char[] conversion to uppercase
     * @since 3.5
     */
    public static final char[] toUpperCase(char[] chars) {
      if (chars == null) return null;
      int length = chars.length;
      char[] upperChars = null;
      for (int i = 0; i < length; i++) {
        char c = chars[i];
        char lc = ScannerHelper.toUpperCase(c);
        if ((c != lc) || (upperChars != null)) {
          if (upperChars == null) {
            System.arraycopy(chars, 0, upperChars = new char[length], 0, i);
          }
          upperChars[i] = lc;
        }
      }
      return upperChars == null ? chars : upperChars;
    }
  
    /**
     * Answers a new array removing leading and trailing spaces (' '). Answers the given array if
     * there is no space characters to remove. <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    chars = { ' ', 'a' , 'b', ' ',  ' ' }
     *    result => { 'a' , 'b' }
     * </pre>
     *   <li>
     *       <pre>
     *    array = { 'A', 'b' }
     *    result => { 'A' , 'b' }
     * </pre>
     * </ol>
     *
     * @param chars the given array
     * @return a new array removing leading and trailing spaces (' ')
     */
    public static final char[] trim(char[] chars) {
  
      if (chars == null) return null;
  
      int start = 0, length = chars.length, end = length - 1;
      while (start < length && chars[start] == ' ') {
        start++;
      }
      while (end > start && chars[end] == ' ') {
        end--;
      }
      if (start != 0 || end != length - 1) {
        return subarray(chars, start, end + 1);
      }
      return chars;
    }
  
    /**
     * Answers a string which is the concatenation of the given array using the '.' as a separator.
     * <br>
     * <br>
     * For example:
     *
     * <ol>
     *   <li>
     *       <pre>
     *    array = { { 'a' } , { 'b' } }
     *    result => "a.b"
     * </pre>
     *   <li>
     *       <pre>
     *    array = { { ' ',  'a' } , { 'b' } }
     *    result => " a.b"
     * </pre>
     * </ol>
     *
     * @param array the given array
     * @return a string which is the concatenation of the given array using the '.' as a separator
     */
    public static final String toString(char[][] array) {
      char[] result = concatWith(array, '.');
      return new String(result);
    }
  
    /**
     * Answers an array of strings from the given array of char array.
     *
     * @param array the given array
     * @return an array of strings
     * @since 3.0
     */
    public static final String[] toStrings(char[][] array) {
      if (array == null) return NO_STRINGS;
      int length = array.length;
      if (length == 0) return NO_STRINGS;
      String[] result = new String[length];
      for (int i = 0; i < length; i++) result[i] = new String(array[i]);
      return result;
    }
  }
  