[Emacs-diffs] trunk r116662: Further follow-up to last change in gmalloc.c.

[Ken Brown]

------------------------------------------------------------
revno: 116662
revision-id: address@hidden
parent: address@hidden
committer: Ken Brown <address@hidden>
branch nick: trunk
timestamp: Tue 2014-03-04 14:02:49 -0500
message:
  
  Further follow-up to last change in gmalloc.c.
  
  * src/gmalloc.c (aligned_alloc): Clarify the code by making `adj'
  represent the actual adjustment needed for alignment.
modified:
  src/ChangeLog                  changelog-20091113204419-o5vbwnq5f7feedwu-1438
  src/gmalloc.c                  gmalloc.c-20091113204419-o5vbwnq5f7feedwu-1085

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2014-03-04 17:35:15 +0000
+++ b/src/ChangeLog     2014-03-04 19:02:49 +0000
@@ -1,3 +1,8 @@
+2014-03-04  Ken Brown  <address@hidden>
+
+       * gmalloc.c (aligned_alloc): Clarify the code by making `adj'
+       represent the actual adjustment needed for alignment.
+
 2014-03-04  Eli Zaretskii  <address@hidden>
 
        * gmalloc.c (aligned_alloc): Don't allocate more memory than

=== modified file 'src/gmalloc.c'
--- a/src/gmalloc.c     2014-03-04 17:35:15 +0000
+++ b/src/gmalloc.c     2014-03-04 19:02:49 +0000
@@ -1597,34 +1597,34 @@
 
   /* Figure out how much we will need to pad this particular block
      to achieve the required alignment.  */
-  adj = (uintptr_t) result % alignment;
-  if (adj == 0)
-    adj = alignment;
+  adj = alignment - (uintptr_t) result % alignment;
+  if (adj == alignment)
+    adj = 0;
 
-  if (adj != 1)
+  if (adj != alignment - 1)
     {
       do
        {
          /* Reallocate the block with only as much excess as it
             needs.  */
          free (result);
-         result = malloc (size + alignment - adj);
+         result = malloc (size + adj);
          if (result == NULL)   /* Impossible unless interrupted.  */
            return NULL;
 
          lastadj = adj;
-         adj = (uintptr_t) result % alignment;
-         if (adj == 0)
-           adj = alignment;
+         adj = alignment - (uintptr_t) result % alignment;
+         if (adj == alignment)
+           adj = 0;
          /* It's conceivable we might have been so unlucky as to get
             a different block with weaker alignment.  If so, this
             block is too short to contain SIZE after alignment
             correction.  So we must try again and get another block,
             slightly larger.  */
-       } while (adj < lastadj);
+       } while (adj > lastadj);
     }
 
-  if (adj != alignment)
+  if (adj != 0)
     {
       /* Record this block in the list of aligned blocks, so that `free'
         can identify the pointer it is passed, which will be in the middle
@@ -1648,7 +1648,7 @@
       if (l != NULL)
        {
          l->exact = result;
-         result = l->aligned = (char *) result + alignment - adj;
+         result = l->aligned = (char *) result + adj;
        }
       UNLOCK_ALIGNED_BLOCKS ();
       if (l == NULL)