Restored missing pieces of some of my patches w...

Restored missing pieces of some of my patches which were accidentally
reverted in r17680. This one includes StringBuilder cleanups and
tail-recursive drop in Iterator.

3 files changed, 14 insertions, 24 deletions

diff --git a/src/library/scala/collection/Iterator.scala b/src/library/scala/collection/Iterator.scala
index 9e8cb67a65..427cd77558 100644
--- a/src/library/scala/collection/Iterator.scala
+++ b/src/library/scala/collection/Iterator.scala
@@ -12,6 +12,7 @@
 package scala.collection
 
 import mutable.{Buffer, ArrayBuffer, ListBuffer}
+import annotation.tailrec
 // import immutable.{List, Nil, ::, Stream}
 
 /** The <code>Iterator</code> object provides various functions for
@@ -298,8 +299,14 @@ trait Iterator[+A] { self =>
    *  @param n the number of elements to drop
    *  @return  the new iterator
    */
-  def drop(n: Int): Iterator[A] =
-    if (n > 0 && hasNext) { next(); drop(n - 1) } else this
+  def drop(n: Int): Iterator[A] = {
+    @tailrec
+    def loop(left: Int): Iterator[A] =
+      if (left > 0 && hasNext) { next; loop(left - 1) }
+      else this
+
+    loop(n)
+  }
 
   /** Advances this iterator past the first `from` elements using `drop`,
    *  and then takes `until - from` elements, using `take`.
diff --git a/src/library/scala/collection/generic/IterableTemplate.scala b/src/library/scala/collection/generic/IterableTemplate.scala
index 3477634821..01cbbcf25b 100644
--- a/src/library/scala/collection/generic/IterableTemplate.scala
+++ b/src/library/scala/collection/generic/IterableTemplate.scala
@@ -151,7 +151,7 @@ trait IterableTemplate[+A, +This <: IterableTemplate[A, This] with Iterable[A]]
    *
    *  @note will not terminate for infinite-sized iterables.
    *  @param that  the other iterable
-   *  @return true, iff both iterables contain the same elements.
+   *  @return true, iff both iterables contain the same elements in the same order.
    *  @note  Might return different results for different runs, unless this iterable is ordered
    */
   def sameElements[B >: A](that: Iterable[B]): Boolean = {
diff --git a/src/library/scala/collection/mutable/StringBuilder.scala b/src/library/scala/collection/mutable/StringBuilder.scala
index db0b633b2d..d1aaa1234d 100644
--- a/src/library/scala/collection/mutable/StringBuilder.scala
+++ b/src/library/scala/collection/mutable/StringBuilder.scala
@@ -804,8 +804,8 @@ final class StringBuilder(initCapacity: Int, private val initValue: String)
       val temp2 = array(n - j)
       if (!hasSurrogate)
         hasSurrogate =
-          (temp >= StringBuilder.MIN_SURROGATE && temp <= StringBuilder.MAX_SURROGATE) ||
-       	  (temp2 >= StringBuilder.MIN_SURROGATE && temp2 <= StringBuilder.MAX_SURROGATE)
+          (temp >= Character.MIN_HIGH_SURROGATE && temp <= Character.MAX_LOW_SURROGATE) ||
+       	  (temp2 >= Character.MIN_HIGH_SURROGATE && temp2 <= Character.MAX_LOW_SURROGATE)
       array(j) = temp2
       array(n - j) = temp
       j -= 1
@@ -815,9 +815,9 @@ final class StringBuilder(initCapacity: Int, private val initValue: String)
       var i = 0
       while (i < count - 1) {
         val c2 = array(i)
-	if (StringBuilder.isLowSurrogate(c2)) {
+	if (Character.isLowSurrogate(c2)) {
           val c1 = array(i + 1)
-          if (StringBuilder.isHighSurrogate(c1)) {
+          if (Character.isHighSurrogate(c1)) {
             array(i) = c1; i += 1
             array(i) = c2
           }
@@ -847,23 +847,6 @@ object StringBuilder {
 
   type Array[T] = scala.Array[T] // !!!
 
-  private val MIN_HIGH_SURROGATE = '\uD800'
-  private val MAX_HIGH_SURROGATE = '\uDBFF'
-
-  private val MIN_LOW_SURROGATE = '\uDC00'
-  private val MAX_LOW_SURROGATE = '\uDFFF'
-
-  // constants <code>java.langCharacter.MIN-/MAX_SURROGATE</code> exist since 1.5
-  private val MIN_SURROGATE = MIN_HIGH_SURROGATE
-  private val MAX_SURROGATE = MAX_LOW_SURROGATE
-
-  // methods <code>java.langCharacter.isLow-/isHighSurrogate</code> exist since 1.5
-  private def isLowSurrogate(ch: Char): Boolean =
-    MIN_LOW_SURROGATE <= ch && ch <= MAX_LOW_SURROGATE
-
-  private def isHighSurrogate(ch: Char): Boolean =
-    MIN_HIGH_SURROGATE <= ch && ch <= MAX_HIGH_SURROGATE
-
   // method <code>java.util.Arrays.copyOf</code> exists since 1.6
   private def copyOf(src: Array[Char], newLength: Int): Array[Char] = {
     val dest = new Array[Char](newLength)