Merge pull request #1304 from paulp/topic/empty-array-optimization

Topic/empty array optimization

8 files changed, 63 insertions, 0 deletions

diff --git a/src/library/scala/Boolean.scala b/src/library/scala/Boolean.scala
index 440e546f19..d7311078ab 100644
--- a/src/library/scala/Boolean.scala
+++ b/src/library/scala/Boolean.scala
@@ -135,5 +135,12 @@ object Boolean extends AnyValCompanion {
    */
   override def toString = "object scala.Boolean"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Boolean]
+   */
+  final val emptyArray = new Array[Boolean](0)
 }
 
diff --git a/src/library/scala/Byte.scala b/src/library/scala/Byte.scala
index df0d2c73b1..02ef913fc5 100644
--- a/src/library/scala/Byte.scala
+++ b/src/library/scala/Byte.scala
@@ -625,6 +625,14 @@ object Byte extends AnyValCompanion {
    */
   override def toString = "object scala.Byte"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Byte]
+   */
+  final val emptyArray = new Array[Byte](0)
+  
   /** Language mandated coercions from Byte to "wider" types.
    */
   implicit def byte2short(x: Byte): Short = x.toShort
diff --git a/src/library/scala/Char.scala b/src/library/scala/Char.scala
index 1fa0c0d9e8..5a1bf16f1d 100644
--- a/src/library/scala/Char.scala
+++ b/src/library/scala/Char.scala
@@ -625,6 +625,14 @@ object Char extends AnyValCompanion {
    */
   override def toString = "object scala.Char"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Char]
+   */
+  final val emptyArray = new Array[Char](0)
+  
   /** Language mandated coercions from Char to "wider" types.
    */
   implicit def char2int(x: Char): Int = x.toInt
diff --git a/src/library/scala/Double.scala b/src/library/scala/Double.scala
index f058d7c26b..7bebbf9418 100644
--- a/src/library/scala/Double.scala
+++ b/src/library/scala/Double.scala
@@ -400,5 +400,13 @@ object Double extends AnyValCompanion {
   /** The String representation of the scala.Double companion object.
    */
   override def toString = "object scala.Double"
+
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Double]
+   */
+  final val emptyArray = new Array[Double](0)
 }
 
diff --git a/src/library/scala/Float.scala b/src/library/scala/Float.scala
index d942acec23..79ed2ac20b 100644
--- a/src/library/scala/Float.scala
+++ b/src/library/scala/Float.scala
@@ -401,6 +401,14 @@ object Float extends AnyValCompanion {
    */
   override def toString = "object scala.Float"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Float]
+   */
+  final val emptyArray = new Array[Float](0)
+  
   /** Language mandated coercions from Float to "wider" types.
    */
   implicit def float2double(x: Float): Double = x.toDouble
diff --git a/src/library/scala/Int.scala b/src/library/scala/Int.scala
index ae36413469..fa2f9a97e7 100644
--- a/src/library/scala/Int.scala
+++ b/src/library/scala/Int.scala
@@ -625,6 +625,14 @@ object Int extends AnyValCompanion {
    */
   override def toString = "object scala.Int"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Int]
+   */
+  final val emptyArray = new Array[Int](0)
+  
   /** Language mandated coercions from Int to "wider" types.
    */
   implicit def int2long(x: Int): Long = x.toLong
diff --git a/src/library/scala/Long.scala b/src/library/scala/Long.scala
index 4ee9383c2a..94204e893c 100644
--- a/src/library/scala/Long.scala
+++ b/src/library/scala/Long.scala
@@ -625,6 +625,14 @@ object Long extends AnyValCompanion {
    */
   override def toString = "object scala.Long"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Long]
+   */
+  final val emptyArray = new Array[Long](0)
+  
   /** Language mandated coercions from Long to "wider" types.
    */
   implicit def long2float(x: Long): Float = x.toFloat
diff --git a/src/library/scala/Short.scala b/src/library/scala/Short.scala
index 35c5fe3ff0..aef8608d2e 100644
--- a/src/library/scala/Short.scala
+++ b/src/library/scala/Short.scala
@@ -625,6 +625,14 @@ object Short extends AnyValCompanion {
    */
   override def toString = "object scala.Short"
 
+
+  /** A highly reusable empty array, useful for avoiding
+   *  allocations when you need one.
+   *
+   *  @return     a constant 0-length Array[Short]
+   */
+  final val emptyArray = new Array[Short](0)
+  
   /** Language mandated coercions from Short to "wider" types.
    */
   implicit def short2int(x: Short): Int = x.toInt