diff --git a/src/gzip/ftgzip.c b/src/gzip/ftgzip.c
index 91b343b..94b9ede 100644
--- a/src/gzip/ftgzip.c
+++ b/src/gzip/ftgzip.c
@@ -731,7 +731,7 @@
 
     /* check for `input' delayed to `inflate' */
 
-    if ( !memory || ! output_len || !output )
+    if ( !memory || !output_len || !output )
       return FT_THROW( Invalid_Argument );
 
     /* this function is modeled after zlib's `uncompress' function */
diff --git a/src/psaux/pshints.c b/src/psaux/pshints.c
index 816c3cc..6b2bd7e 100644
--- a/src/psaux/pshints.c
+++ b/src/psaux/pshints.c
@@ -331,7 +331,7 @@
   cf2_hintmap_map( CF2_HintMap  hintmap,
                    CF2_Fixed    csCoord )
   {
-    if ( hintmap->count == 0 || ! hintmap->hinted )
+    if ( hintmap->count == 0 || !hintmap->hinted )
     {
       /* there are no hints; use uniform scale and zero offset */
       return FT_MulFix( csCoord, hintmap->scale );
diff --git a/src/type1/t1gload.c b/src/type1/t1gload.c
index 75062ee..11870b1 100644
--- a/src/type1/t1gload.c
+++ b/src/type1/t1gload.c
@@ -545,7 +545,7 @@
 
 
           /* First of all, scale the points, if we are not hinting */
-          if ( !hinting || ! decoder.builder.hints_funcs )
+          if ( !hinting || !decoder.builder.hints_funcs )
             for ( n = cur->n_points; n > 0; n--, vec++ )
             {
               vec->x = FT_MulFix( vec->x, x_scale );