/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.hadoop.hbase.security.visibility;
  
  import java.util.regex.Pattern;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  
  /**
   * A simple validator that validates the labels passed
   */
  @InterfaceAudience.Private
  public class VisibilityLabelsValidator {
    private static final boolean[] validAuthChars = new boolean[256];
  
    public static final String regex = "[A-Za-z_\\-\\:\\/\\.0-9]+";
    public static final Pattern pattern = Pattern.compile(regex);
  
    static {
      for (int i = 0; i < 256; i++) {
        validAuthChars[i] = false;
      }
  
      for (int i = 'a'; i <= 'z'; i++) {
        validAuthChars[i] = true;
      }
  
      for (int i = 'A'; i <= 'Z'; i++) {
        validAuthChars[i] = true;
      }
  
      for (int i = '0'; i <= '9'; i++) {
        validAuthChars[i] = true;
      }
  
      validAuthChars['_'] = true;
      validAuthChars['-'] = true;
      validAuthChars[':'] = true;
      validAuthChars['.'] = true;
      validAuthChars['/'] = true;
    }
    
    static final boolean isValidAuthChar(byte b) {
      return validAuthChars[0xff & b];
    }
  
    public static final boolean isValidLabel(byte[] label) {
      for (int i = 0; i < label.length; i++) {
        if (!isValidAuthChar(label[i])) {
          return false;
        }
      }
      return true;
    }
  }