fix ConcatenatedStream for real and add testcase

2012-10-09  Paolo Bonzini  <bonzini@gnu.org>
            Holger Freyther  <holger@freyther.de>

	* kernel/StreamOps.st: Fix previous changeset.
	* tests/streams.st: New.
	* tests/streams.ok: New.

ChangeLog

@@ -1,3 +1,10 @@
+2012-10-09  Paolo Bonzini  <bonzini@gnu.org>
+            Holger Freyther  <holger@freyther.de>
+
+	* kernel/StreamOps.st: Fix previous changeset.
+	* tests/streams.st: New.
+	* tests/streams.ok: New.
+
 2012-10-08  Paolo Bonzini  <bonzini@gnu.org>
 
 	* kernel/StreamOps.st: Ensure "last" is up to date when a

kernel/StreamOps.st

@@ -81,9 +81,10 @@ Stream subclass: ConcatenatedStream [
         "This is somewhat performance-sensitive, so avoid testing for an
          empty collection."
 	[(s := streams at: 1) atEnd] whileTrue: 
-		[lastStart := startPos.
-		startPos := startPos + curPos.
-		curPos := 0.
+		[curPos > 0 ifTrue: [
+                    lastStart := startPos.
+                    startPos := startPos + curPos.
+                    curPos := 0].
                 streams size = 1 ifTrue: [last := streams first. ^nil].
 		last := streams removeFirst].
 	^s

tests/streams.ok

@@ -0,0 +1,14 @@
+
+Execution begins...
+$1
+$2
+$3
+'123'
+$4
+$5
+'456'
+$6
+true
+'456'
+nil
+returned value is nil

tests/streams.st

@@ -0,0 +1,55 @@
+
+"======================================================================
+|
+|   Regression tests for Streams
+|
+|
+ ======================================================================"
+
+
+"======================================================================
+|
+| Copyright (C) 2012 Free Software Foundation.
+| Written by Holger Hans Peter Freyther.
+|
+| This file is part of GNU Smalltalk.
+|
+| GNU Smalltalk is free software; you can redistribute it and/or modify it
+| under the terms of the GNU General Public License as published by the Free
+| Software Foundation; either version 2, or (at your option) any later version.
+| 
+| GNU Smalltalk is distributed in the hope that it will be useful, but WITHOUT
+| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+| FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+| details.
+| 
+| You should have received a copy of the GNU General Public License along with
+| GNU Smalltalk; see the file COPYING.  If not, write to the Free Software
+| Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  
+|
+ ======================================================================"
+
+Eval [
+    | concat streamA streamB |
+    streamA := '123' readStream.
+    streamB := '456' readStream.
+    concat := streamA, streamB.
+
+    "Should print 123"
+    concat next printNl.
+    concat next printNl.
+    concat next printNl.
+    (concat copyFrom: 0 to: 2) printNl.
+
+    "Should print 45"
+    concat next printNl.
+    concat next printNl.
+    (concat copyFrom: 3 to: 5) printNl.
+
+    "Should print 6"
+    concat next printNl.
+    concat atEnd printNl.
+    (concat copyFrom: 3 to: 5) printNl.
+
+    concat stream printNl.
+]

tests/testsuite.at

@@ -52,6 +52,7 @@ AT_DIFF_TEST([getopt.st])
 AT_DIFF_TEST([quit.st])
 AT_DIFF_TEST([pools.st])
 AT_DIFF_TEST([shape.st])
+AT_DIFF_TEST([streams.st])
 
 AT_BANNER([Other simple tests.])
 AT_DIFF_TEST([ackermann.st])