2012-10-06 Thomas König <tkoenig@gcc.gnu.org>

	PR libfortran/54736
	Backport from trunk
	* runtime/environ.c (search_unit):  Correct logic
	for binary search.
	(mark_single):  Fix index errors.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_7-branch@192408 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index cfddafe..60f0fa9 100644 (file)
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,11 @@
+2012-10-06  Thomas König  <tkoenig@gcc.gnu.org>
+
+       PR libfortran/54736
+       Backport from trunk
+       * runtime/environ.c (search_unit):  Correct logic
+       for binary search.
+       (mark_single):  Fix index errors.
+
 2012-09-20  Release Manager
 
        * GCC 4.7.2 released.

diff --git a/libgfortran/runtime/environ.c b/libgfortran/runtime/environ.c
index 6bd8886..a7bda45 100644 (file)
--- a/libgfortran/runtime/environ.c
+++ b/libgfortran/runtime/environ.c
@@ -446,21 +446,35 @@ search_unit (int unit, int *ip)
 {
   int low, high, mid;
 
-  low = -1;
-  high = n_elist;
-  while (high - low > 1)
+  if (n_elist == 0)
+    {
+      *ip = 0;
+      return 0;
+    }
+
+  low = 0;
+  high = n_elist - 1;
+
+  do 
     {
       mid = (low + high) / 2;
-      if (unit <= elist[mid].unit)
-       high = mid;
+      if (unit == elist[mid].unit)
+       {
+         *ip = mid;
+         return 1;
+       }
+      else if (unit > elist[mid].unit)
+       low = mid + 1;
       else
-       low = mid;
-    }
-  *ip = high;
-  if (elist[high].unit == unit)
-    return 1;
+       high = mid - 1;
+    } while (low <= high);
+
+  if (unit > elist[mid].unit)
+    *ip = mid + 1;
   else
-    return 0;
+    *ip = mid;
+
+  return 0;
 }
 
 /* This matches a keyword.  If it is found, return the token supplied,
@@ -575,13 +589,13 @@ mark_single (int unit)
     }
   if (search_unit (unit, &i))
     {
-      elist[unit].conv = endian;
+      elist[i].conv = endian;
     }
   else
     {
-      for (j=n_elist; j>=i; j--)
+      for (j=n_elist-1; j>=i; j--)
        elist[j+1] = elist[j];
-    
+
       n_elist += 1;
       elist[i].unit = unit;
       elist[i].conv = endian;