From 80d3a625a75ba054eef58eac94dc3a8066690c36 Mon Sep 17 00:00:00 2001
From: cremet <cremet@epfl.ch>
Date: Tue, 26 Aug 2003 15:28:51 +0000
Subject: - Added "PiLib" library and associated examples.

- Fixed some files in the package "scala.concurrent".
---
 sources/examples/pilib/elasticBuffer.scala | 75 ++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 sources/examples/pilib/elasticBuffer.scala

(limited to 'sources/examples/pilib/elasticBuffer.scala')

diff --git a/sources/examples/pilib/elasticBuffer.scala b/sources/examples/pilib/elasticBuffer.scala
new file mode 100644
index 0000000000..50e61c291a
--- /dev/null
+++ b/sources/examples/pilib/elasticBuffer.scala
@@ -0,0 +1,75 @@
+object elasticBuffer {
+
+  import scala.concurrent.pilib._;
+
+  /**
+  * Recursive type for channels that carry a "String" channel and
+  * an object of the type we define.
+  */
+  class MetaChan extends Chan[Pair[Chan[String], MetaChan]];
+
+  def Buffer(put: Chan[String], get: Chan[String]): unit =  {
+
+    /**
+    * An empty buffer cell, ready to pass on (o,r) to the left.
+    */
+    def Bl(i:Chan[String], l: MetaChan,
+	   o: Chan[String], r: MetaChan): unit =
+	     choice (
+	       l(Pair(o,r)) * (System.out.println("Removed one cell.")),
+	       i * (inp => Cl(i, l, o, r, inp))
+	     );
+
+    /**
+    * A buffer cell containing a value, ready to receive (o,r) from the right.
+    */
+    def Cl(i: Chan[String], l: MetaChan,
+	  o: Chan[String], r: MetaChan, content: String): unit =
+	    choice (
+	      o(content) * (Bl(i,l,o,r)),
+	      i * (inp => Dl(i,l,o,r,content, inp)),
+	      r * ( { case Pair(newo, newr) => Cl(i,l,newo,newr,content) })
+	    );
+
+    /**
+    * Two joined buffer cells, of type Cl.
+    */
+    def Dl(i: Chan[String], l: MetaChan,
+	  o: Chan[String], r: MetaChan,
+	  content: String, inp: String): unit = {
+      val newlr = new MetaChan;
+      val newio = new Chan[String];
+      spawn < Cl(i, l, newio, newlr, inp) | Cl(newio, newlr, o, r,content) >;
+    }
+
+    // l and r channels for the leftmost and rightmost cell, respectively.
+    val unused1 = new MetaChan;
+    val unused2 = new MetaChan;
+
+    Bl(put, unused1, get, unused2);
+  }
+
+  val random = new java.util.Random();
+
+  def Producer(n: int, put: Chan[String]): unit = {
+    Thread.sleep(1 + random.nextInt(1000));
+    val msg = "object " + n;
+    put.write(msg);
+    System.out.println("Producer gave " + msg);
+    Producer(n + 1, put)
+  }
+
+  def Consumer(get: Chan[String]): unit = {
+    Thread.sleep(1 + random.nextInt(1000));
+    val msg = get.read;
+    System.out.println("Consummer took " + msg);
+    Consumer(get)
+  }
+
+  def main(args: Array[String]): unit = {
+    val put = new Chan[String];
+    val get = new Chan[String];
+    spawn < Producer(0, put) | Consumer(get) | Buffer(put, get) >
+  }
+
+}
-- 
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