bugfix: rounding error in stralloc_reverse_blocks

1 files changed, 3 insertions, 2 deletions

diff --git a/src/libstddjb/stralloc_reverse_blocks.c b/src/libstddjb/stralloc_reverse_blocks.c
index 86b7fc4..731d635 100644
--- a/src/libstddjb/stralloc_reverse_blocks.c
+++ b/src/libstddjb/stralloc_reverse_blocks.c
@@ -10,8 +10,9 @@ void stralloc_reverse_blocks (stralloc *sa, size_t size)
   char tmp[size] ;
   for (; i < n ; i++)
   {
+    size_t k = sa->len - (i + 1) * size ;
     memcpy(tmp, sa->s + i * size, size) ;
-    memcpy(sa->s + i * size, sa->s + (2*n - 1 - i) * size, size) ;
-    memcpy(sa->s + (2*n - 1 - i) * size, tmp, size) ;
+    memcpy(sa->s + i * size, sa->s + k, size) ;
+    memcpy(sa->s + k, tmp, size) ;
   }
 }