A safety improvement for random path generation...

A safety improvement for random path generation, and a small change to
Random for a more general interface. Review by community.

1 files changed, 16 insertions, 7 deletions

diff --git a/src/library/scala/util/Random.scala b/src/library/scala/util/Random.scala
index ffa248d638..cd9d5eed0e 100644
--- a/src/library/scala/util/Random.scala
+++ b/src/library/scala/util/Random.scala
@@ -89,14 +89,12 @@ class Random(val self: java.util.Random) {
     List.fill(length)(safeChar()).mkString
   }
 
-  /** Returns a pseudorandomly generated String drawing upon
-   *  only ASCII characters between 33 and 126.
+  /** Returns the next pseudorandom, uniformly distributed value
+   *  from the ASCII range 33-126.
    */
-  def nextASCIIString(length: Int) = {
-    val (min, max) = (33, 126)
-    def nextDigit = nextInt(max - min) + min
-
-    new String(Array.fill(length)(nextDigit.toByte), "ASCII")
+  def nextPrintableChar(): Char = {
+    val (low, high) = (33, 126)
+    (self.nextInt(high - low) + low).toChar
   }
 
   def setSeed(seed: Long) { self.setSeed(seed) }
@@ -111,6 +109,17 @@ object Random extends Random {
   import collection.mutable.ArrayBuffer
   import collection.generic.CanBuildFrom
 
+  /** Returns a Stream of pseudorandomly chosen alphanumeric characters,
+   *  equally chosen from A-Z, a-z, and 0-9.
+   *
+   *  @since 2.8
+   */
+  def alphanumeric: Stream[Char] = {
+    def isAlphaNum(c: Char) = (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9')
+
+    Stream continually nextPrintableChar filter isAlphaNum
+  }
+
   /** Returns a new collection of the same type in a randomly chosen order.
    *
    *  @param  coll    the TraversableOnce to shuffle