org.apache.spark.sql.catalyst.util.StringUtils.scala Maven / Gradle / Ivy

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/*
 * 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.spark.sql.catalyst.util

import java.util.regex.Pattern

import org.apache.spark.unsafe.types.UTF8String

object StringUtils {

  // replace the _ with .{1} exactly match 1 time of any character
  // replace the % with .*, match 0 or more times with any character
  def escapeLikeRegex(v: String): String = {
    if (!v.isEmpty) {
      "(?s)" + (' ' +: v.init).zip(v).flatMap {
        case (prev, '\\') => ""
        case ('\\', c) =>
          c match {
            case '_' => "_"
            case '%' => "%"
            case _ => Pattern.quote("\\" + c)
          }
        case (prev, c) =>
          c match {
            case '_' => "."
            case '%' => ".*"
            case _ => Pattern.quote(Character.toString(c))
          }
      }.mkString
    } else {
      v
    }
  }

  private[this] val trueStrings = Set("t", "true", "y", "yes", "1").map(UTF8String.fromString)
  private[this] val falseStrings = Set("f", "false", "n", "no", "0").map(UTF8String.fromString)

  def isTrueString(s: UTF8String): Boolean = trueStrings.contains(s.toLowerCase)
  def isFalseString(s: UTF8String): Boolean = falseStrings.contains(s.toLowerCase)
}