From 392f089a2cddea816d65fe2228bb44fe4fbad5d3 Mon Sep 17 00:00:00 2001
From: Richard Brooksby <rb@ravenbrook.com>
Date: Mon, 24 Feb 2014 23:02:42 +0000
Subject: [PATCH] Bug fix.  nonsensical case in cbsfindlargest when size is
 passed as zero.

Added RangeCopy.

Copied from Perforce
 Change: 184496
 ServerID: perforce.ravenbrook.com
---
 mps/code/cbs.c   | 11 ++++++++---
 mps/code/range.c |  8 ++++++++
 mps/code/range.h |  1 +
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/mps/code/cbs.c b/mps/code/cbs.c
index fc4ae964603..f20896b97b7 100644
--- a/mps/code/cbs.c
+++ b/mps/code/cbs.c
@@ -764,7 +764,7 @@ static void cbsFindDeleteRange(Range rangeReturn, Range oldRangeReturn,
        need to allocate a new block. */
     AVER(res == ResOK);
   } else
-    mps_lib_memcpy(oldRangeReturn, rangeReturn, sizeof(RangeStruct));
+    RangeCopy(oldRangeReturn, rangeReturn);
 }
 
 
@@ -873,8 +873,13 @@ Bool CBSFindLargest(Range rangeReturn, Range oldRangeReturn,
       AVER(CBSBlockSize(block) >= maxSize);
       RangeInit(&range, CBSBlockBase(block), CBSBlockLimit(block));
       AVER(RangeSize(&range) >= maxSize);
-      cbsFindDeleteRange(rangeReturn, oldRangeReturn, cbs, &range,
-                         size, findDelete);
+      if (size > 0)
+        cbsFindDeleteRange(rangeReturn, oldRangeReturn, cbs, &range,
+                           size, findDelete);
+      else {
+        RangeCopy(rangeReturn, &range); /* FIXME: sense? */
+        RangeCopy(oldRangeReturn, &range);
+      }
     }
   }
 
diff --git a/mps/code/range.c b/mps/code/range.c
index c12682ddd3a..eb22a9d22e6 100644
--- a/mps/code/range.c
+++ b/mps/code/range.c
@@ -43,6 +43,14 @@ void RangeFinish(Range range)
   range->base = range->limit = NULL;
 }
 
+void RangeCopy(Range toRange, Range fromRange)
+{
+  AVERT(Range, fromRange);
+  toRange->base = fromRange->base;
+  toRange->limit = fromRange->limit;
+  toRange->sig = RangeSig;
+}
+
 Res RangeDescribe(Range range, mps_lib_FILE *stream)
 {
   Res res;
diff --git a/mps/code/range.h b/mps/code/range.h
index 69bd95d31a8..ea113ab656e 100644
--- a/mps/code/range.h
+++ b/mps/code/range.h
@@ -29,6 +29,7 @@ typedef struct RangeStruct *Range;
 
 extern void RangeInit(Range range, Addr base, Addr limit);
 extern void RangeFinish(Range range);
+extern void RangeCopy(Range toRange, Range fromRange);
 extern Res RangeDescribe(Range range, mps_lib_FILE *stream);
 extern Bool RangeCheck(Range range);
 extern Bool RangeIsAligned(Range range, Align align);