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/*
 * Scala (https://www.scala-lang.org)
 *
 * Copyright EPFL and Lightbend, Inc.
 *
 * Licensed under Apache License 2.0
 * (http://www.apache.org/licenses/LICENSE-2.0).
 *
 * See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.
 */

package scala.collection.mutable

import scala.collection.{IterableFactoryDefaults, IterableOnce}
import scala.collection.immutable.WrappedString

import scala.Predef.{ // unimport char-related implicit conversions to avoid triggering them accidentally
  genericArrayOps => _,
  charArrayOps => _,
  genericWrapArray => _,
  wrapCharArray => _,
  wrapString => _,
 //_
}

/** A builder for mutable sequence of characters.  This class provides an API
  * mostly compatible with `java.lang.StringBuilder`, except where there are
  * conflicts with the Scala collections API (such as the `reverse` method.)
  *
  * $multipleResults
  *
  * @define Coll `mutable.IndexedSeq`
  * @define coll string builder
  * @see [[http://docs.scala-lang.org/overviews/collections/concrete-mutable-collection-classes.html#stringbuilders "Scala's Collection Library overview"]]
  * section on `StringBuilders` for more information.
  */
@SerialVersionUID(3L)
final class StringBuilder(val underlying: java.lang.StringBuilder) extends AbstractSeq[Char]
  with ReusableBuilder[Char, String]
  with IndexedSeq[Char]
  with IndexedSeqOps[Char, IndexedSeq, StringBuilder]
  with IterableFactoryDefaults[Char, IndexedSeq]
  with java.lang.CharSequence
  with Serializable {

  def this() = this(new java.lang.StringBuilder)

  /** Constructs a string builder with no characters in it and an
    *  initial capacity specified by the `capacity` argument.
    *
    *  @param  capacity  the initial capacity.
    *  @throws java.lang.NegativeArraySizeException  if capacity < 0.
    */
  def this(capacity: Int) = this(new java.lang.StringBuilder(capacity))

  /** Constructs a string builder with initial characters
    *  equal to characters of `str`.
    */
  def this(str: String) = this(new java.lang.StringBuilder(str))

  /** Constructs a string builder initialized with string value `initValue`
    *  and with additional character capacity `initCapacity`.
    */
  def this(initCapacity: Int, initValue: String) =
    this(new java.lang.StringBuilder(initValue.length + initCapacity) append initValue)

  // Methods required to make this an IndexedSeq:
  def apply(i: Int): Char = underlying.charAt(i)

  override protected def fromSpecific(coll: scala.collection.IterableOnce[Char]): StringBuilder =
    new StringBuilder() appendAll coll

  override protected def newSpecificBuilder: Builder[Char, StringBuilder] =
    new GrowableBuilder(new StringBuilder())

  override def empty: StringBuilder = new StringBuilder()

  @inline def length: Int = underlying.length

  def length_=(n: Int): Unit = underlying.setLength(n)

  override def knownSize: Int = super[IndexedSeqOps].knownSize

  def addOne(x: Char): this.type = { underlying.append(x); this }

  def clear(): Unit = underlying.setLength(0)

  /** Overloaded version of `addAll` that takes a string */
  def addAll(s: String): this.type = { underlying.append(s); this }

  /** Alias for `addAll` */
  def ++= (s: String): this.type = addAll(s)

  def result() = underlying.toString

  override def toString: String = result()

  override def toArray[B >: Char](implicit ct: scala.reflect.ClassTag[B]) =
    ct.runtimeClass match {
      case java.lang.Character.TYPE => toCharArray.asInstanceOf[Array[B]]
      case _ => super.toArray
    }

  /** Returns the contents of this StringBuilder as an `Array[Char]`.
   *
   *  @return  An array with the characters from this builder.
   */
  def toCharArray: Array[Char] = {
    val len = underlying.length
    val arr = new Array[Char](len)
    underlying.getChars(0, len, arr, 0)
    arr
  }

  // append* methods delegate to the underlying java.lang.StringBuilder:

  def appendAll(xs: String): StringBuilder = {
    underlying append xs
    this
  }

  /** Appends the string representation of the given argument,
    *  which is converted to a String with `String.valueOf`.
    *
    *  @param  x   an `Any` object.
    *  @return     this StringBuilder.
    */
  def append(x: Any): StringBuilder = {
    underlying append String.valueOf(x)
    this
  }

  /** Appends the given String to this sequence.
    *
    *  @param  s   a String.
    *  @return     this StringBuilder.
    */
  def append(s: String): StringBuilder = {
    underlying append s
    this
  }

  /** Appends the given CharSequence to this sequence.
    *
    *  @param  cs   a CharSequence.
    *  @return     this StringBuilder.
    */
  def append(cs: java.lang.CharSequence): StringBuilder = {
    underlying.append(cs match {
      // Both cases call into append(), but java SB
      // looks up type at runtime and has fast path for SB.
      case s: StringBuilder => s.underlying
      case _                => cs
    })
    this
  }

  /** Appends the specified string builder to this sequence.
    *
    *  @param s
    *  @return
    */
  def append(s: StringBuilder): StringBuilder = {
    underlying append s.underlying
    this
  }

  /** Appends all the Chars in the given IterableOnce[Char] to this sequence.
    *
    *  @param  xs  the characters to be appended.
    *  @return     this StringBuilder.
    */
  def appendAll(xs: IterableOnce[Char]): StringBuilder = {
    xs match {
      case x: WrappedString => underlying append x.unwrap
      case x: ArraySeq.ofChar => underlying append x.array
      case x: StringBuilder => underlying append x.underlying
      case _ =>
        val ks = xs.knownSize
        if (ks != 0) {
          val b = underlying
          if (ks > 0) b.ensureCapacity(b.length + ks)
          val it = xs.iterator
          while (it.hasNext) { b append it.next() }
        }
    }
    this
  }

  /** Appends all the Chars in the given Array[Char] to this sequence.
    *
    *  @param  xs  the characters to be appended.
    *  @return     a reference to this object.
    */
  def appendAll(xs: Array[Char]): StringBuilder = {
    underlying append xs
    this
  }

  /** Appends a portion of the given Array[Char] to this sequence.
    *
    *  @param  xs      the Array containing Chars to be appended.
    *  @param  offset  the index of the first Char to append.
    *  @param  len     the numbers of Chars to append.
    *  @return         this StringBuilder.
    */
  def appendAll(xs: Array[Char], offset: Int, len: Int): StringBuilder = {
    underlying.append(xs, offset, len)
    this
  }

  /** Append the String representation of the given primitive type
    *  to this sequence.  The argument is converted to a String with
    *  String.valueOf.
    *
    *  @param   x  a primitive value
    *  @return     This StringBuilder.
    */
  def append(x: Boolean): StringBuilder = { underlying append x ; this }
  def append(x: Byte): StringBuilder = append(x.toInt)
  def append(x: Short): StringBuilder = append(x.toInt)
  def append(x: Int): StringBuilder = { underlying append x ; this }
  def append(x: Long): StringBuilder = { underlying append x ; this }
  def append(x: Float): StringBuilder = { underlying append x ; this }
  def append(x: Double): StringBuilder = { underlying append x ; this }
  def append(x: Char): StringBuilder = { underlying append x ; this }

  /** Remove a subsequence of Chars from this sequence, starting at the
    *  given start index (inclusive) and extending to the end index (exclusive)
    *  or to the end of the String, whichever comes first.
    *
    *  @param  start  The beginning index, inclusive.
    *  @param  end    The ending index, exclusive.
    *  @return        This StringBuilder.
    *  @throws StringIndexOutOfBoundsException   if start < 0 || start > end
    */
  def delete(start: Int, end: Int): StringBuilder = {
    underlying.delete(start, end)
    this
  }

  /** Replaces a subsequence of Chars with the given String.  The semantics
    *  are as in delete, with the String argument then inserted at index 'start'.
    *
    *  @param  start  The beginning index, inclusive.
    *  @param  end    The ending index, exclusive.
    *  @param  str    The String to be inserted at the start index.
    *  @return        This StringBuilder.
    *  @throws StringIndexOutOfBoundsException if start < 0, start > length, or start > end
    */
  def replace(start: Int, end: Int, str: String): StringBuilder = {
    underlying.replace(start, end, str)
    this
  }

  /** Inserts a subarray of the given Array[Char] at the given index
    *  of this sequence.
    *
    * @param  index   index at which to insert the subarray.
    * @param  str     the Array from which Chars will be taken.
    * @param  offset  the index of the first Char to insert.
    * @param  len     the number of Chars from 'str' to insert.
    * @return         This StringBuilder.
    *
    * @throws StringIndexOutOfBoundsException  if index < 0, index > length,
    *         offset < 0, len < 0, or (offset + len) > str.length.
    */
  def insertAll(index: Int, str: Array[Char], offset: Int, len: Int): StringBuilder = {
    underlying.insert(index, str, offset, len)
    this
  }

  /** Inserts the String representation (via String.valueOf) of the given
    *  argument into this sequence at the given index.
    *
    *  @param  index   the index at which to insert.
    *  @param  x       a value.
    *  @return         this StringBuilder.
    *  @throws StringIndexOutOfBoundsException  if the index is out of bounds.
    */
  def insert(index: Int, x: Any): StringBuilder = insert(index, String.valueOf(x))

  /** Inserts the String into this character sequence.
    *
    *  @param  index the index at which to insert.
    *  @param  x     a String.
    *  @return       this StringBuilder.
    *  @throws StringIndexOutOfBoundsException  if the index is out of bounds.
    */
  def insert(index: Int, x: String): StringBuilder = {
    underlying.insert(index, x)
    this
  }

  /** Inserts the given Seq[Char] into this sequence at the given index.
    *
    *  @param  index the index at which to insert.
    *  @param  xs    the Seq[Char].
    *  @return       this StringBuilder.
    *  @throws StringIndexOutOfBoundsException  if the index is out of bounds.
    */
  def insertAll(index: Int, xs: IterableOnce[Char]): StringBuilder =
    insertAll(index, (ArrayBuilder.make[Char] ++= xs).result())

  /** Inserts the given Array[Char] into this sequence at the given index.
    *
    *  @param  index the index at which to insert.
    *  @param  xs    the Array[Char].
    *  @return       this StringBuilder.
    *  @throws StringIndexOutOfBoundsException  if the index is out of bounds.
    */
  def insertAll(index: Int, xs: Array[Char]): StringBuilder = {
    underlying.insert(index, xs)
    this
  }

  /** Calls String.valueOf on the given primitive value, and inserts the
    *  String at the given index.
    *
    *  @param  index the offset position.
    *  @param  x     a primitive value.
    *  @return       this StringBuilder.
    */
  def insert(index: Int, x: Boolean): StringBuilder = insert(index, String.valueOf(x))
  def insert(index: Int, x: Byte): StringBuilder    = insert(index, x.toInt)
  def insert(index: Int, x: Short): StringBuilder   = insert(index, x.toInt)
  def insert(index: Int, x: Int): StringBuilder     = insert(index, String.valueOf(x))
  def insert(index: Int, x: Long): StringBuilder    = insert(index, String.valueOf(x))
  def insert(index: Int, x: Float): StringBuilder   = insert(index, String.valueOf(x))
  def insert(index: Int, x: Double): StringBuilder  = insert(index, String.valueOf(x))
  def insert(index: Int, x: Char): StringBuilder    = insert(index, String.valueOf(x))

  /** Sets the length of the character sequence.  If the current sequence
    *  is shorter than the given length, it is padded with nulls; if it is
    *  longer, it is truncated.
    *
    *  @param  len  the new length
    *  @throws IndexOutOfBoundsException if the argument is negative.
    */
  def setLength(len: Int): Unit = underlying.setLength(len)

  def update(idx: Int, elem: Char): Unit = underlying.setCharAt(idx, elem)


  /** Like reverse, but destructively updates the target StringBuilder.
   *
   *  @return   the reversed StringBuilder (same as the target StringBuilder)
   */
  @deprecated("Use reverseInPlace instead", "2.13.0")
  final def reverseContents(): this.type = reverseInPlace()

  /** Like reverse, but destructively updates the target StringBuilder.
   *
   *  @return   the reversed StringBuilder (same as the target StringBuilder)
   */
  def reverseInPlace(): this.type = {
    underlying.reverse()
    this
  }


  /** Returns the current capacity, which is the size of the underlying array.
   *  A new array will be allocated if the current capacity is exceeded.
   *
   *  @return  the capacity
   */
  def capacity: Int = underlying.capacity

  /** Ensure that the capacity is at least the given argument.
   *  If the argument is greater than the current capacity, new
   *  storage will be allocated with size equal to the given
   *  argument or to `(2 * capacity + 2)`, whichever is larger.
   *
   *  @param newCapacity    the minimum desired capacity.
   */
  def ensureCapacity(newCapacity: Int): Unit = { underlying.ensureCapacity(newCapacity) }

  /** Returns the Char at the specified index, counting from 0 as in Arrays.
   *
   *  @param  index   the index to look up
   *  @return         the Char at the given index.
   *  @throws IndexOutOfBoundsException  if the index is out of bounds.
   */
  def charAt(index: Int): Char = underlying.charAt(index)

  /** Removes the Char at the specified index.  The sequence is
   *  shortened by one.
   *
   *  @param  index  The index to remove.
   *  @return        This StringBuilder.
   *  @throws IndexOutOfBoundsException  if the index is out of bounds.
   */
  def deleteCharAt(index: Int): this.type = {
    underlying.deleteCharAt(index)
    this
  }

  /** Update the sequence at the given index to hold the specified Char.
   *
   *  @param  index   the index to modify.
   *  @param  ch      the new Char.
   *  @throws IndexOutOfBoundsException  if the index is out of bounds.
   */
  def setCharAt(index: Int, ch: Char): this.type = {
    underlying.setCharAt(index, ch)
    this
  }

  /** Returns a new String made up of a subsequence of this sequence,
   *  beginning at the given index and extending to the end of the sequence.
   *
   *  target.substring(start)  is equivalent to  target.drop(start)
   *
   *  @param  start  The starting index, inclusive.
   *  @return        The new String.
   *  @throws IndexOutOfBoundsException  if the index is out of bounds.
   */
  def substring(start: Int): String = underlying.substring(start, length)

  /** Returns a new String made up of a subsequence of this sequence,
   *  beginning at the start index (inclusive) and extending to the
   *  end index (exclusive).
   *
   *  target.substring(start, end)  is equivalent to  target.slice(start, end).mkString
   *
   *  @param  start  The beginning index, inclusive.
   *  @param  end    The ending index, exclusive.
   *  @return The new String.
   *  @throws StringIndexOutOfBoundsException If either index is out of bounds,
   *          or if start > end.
   */
  def substring(start: Int, end: Int): String = underlying.substring(start, end)

  /** For implementing CharSequence.
   */
  def subSequence(start: Int, end: Int): java.lang.CharSequence =
    underlying.substring(start, end)

  /** Finds the index of the first occurrence of the specified substring.
   *
   *  @param    str       the target string to search for
   *  @return             the first applicable index where target occurs, or -1 if not found.
   */
  def indexOf(str: String): Int = underlying.indexOf(str)

  /** Finds the index of the first occurrence of the specified substring.
   *
   *  @param    str       the target string to search for
   *  @param    fromIndex the smallest index in the source string to consider
   *  @return             the first applicable index where target occurs, or -1 if not found.
   */
  def indexOf(str: String, fromIndex: Int): Int = underlying.indexOf(str, fromIndex)

  /** Finds the index of the last occurrence of the specified substring.
   *
   *  @param    str       the target string to search for
   *  @return             the last applicable index where target occurs, or -1 if not found.
   */
  def lastIndexOf(str: String): Int = underlying.lastIndexOf(str)

  /** Finds the index of the last occurrence of the specified substring.
   *
   *  @param    str       the target string to search for
   *  @param    fromIndex the smallest index in the source string to consider
   *  @return             the last applicable index where target occurs, or -1 if not found.
   */
  def lastIndexOf(str: String, fromIndex: Int): Int = underlying.lastIndexOf(str, fromIndex)

  /** Tests whether this builder is empty.
   *
   *  This method is required for JDK15+ compatibility
   *
   *  @return  `true` if this builder contains nothing, `false` otherwise.
   */
  override def isEmpty: Boolean = underlying.length() == 0
}

object StringBuilder {
  @deprecated("Use `new StringBuilder()` instead of `StringBuilder.newBuilder`", "2.13.0")
  def newBuilder = new StringBuilder
}




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