libc/wchar: Remove the unnecessary cast

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

libs/libc/wchar/lib_btowc.c

@@ -66,13 +66,13 @@ wint_t btowc(int c)
 
   b = (char)c;
 
-  retval = mbtowc(&pwc, (FAR const char *)&b, 1);
+  retval = mbtowc(&pwc, &b, 1);
 
   if (retval != 0 && retval != 1)
     {
       return WEOF;
     }
 
-  return (wint_t)pwc;
+  return pwc;
 }
 #endif

libs/libc/wchar/lib_mbrtowc.c

@@ -68,13 +68,6 @@ size_t mbrtowc(FAR wchar_t *pwc, FAR const char *s,
       retval = mbtowc(pwc, s, n);
     }
 
-  if (retval == -1)
-    {
-      return (size_t)(-1);
-    }
-  else
-    {
-      return (size_t)retval;
-    }
+  return retval;
 }
 #endif

libs/libc/wchar/lib_wcrtomb.c

@@ -69,13 +69,6 @@ size_t wcrtomb(FAR char *s, wchar_t wc, FAR mbstate_t *ps)
       retval = wctomb(s, wc);
     }
 
-  if (retval == -1)
-    {
-      return (size_t)(-1);
-    }
-  else
-    {
-      return (size_t)retval;
-    }
+  return retval;
 }
 #endif

libs/libc/wchar/lib_wcscmp.c

@@ -63,10 +63,10 @@ int wcscmp(FAR const wchar_t *s1, FAR const wchar_t *s2)
     {
       if (*s1++ == 0)
         {
-          return (0);
+          return 0;
         }
     }
 
-  return (*s1 - *--s2);
+  return *s1 - *--s2;
 }
 #endif

libs/libc/wchar/lib_wctob.c

@@ -57,6 +57,6 @@ int wctob(wint_t wc)
       return EOF;
     }
 
-  return wctomb(pmb, wc) == 1 ? (int)pmb[0] : EOF;
+  return wctomb(pmb, wc) == 1 ? pmb[0] : EOF;
 }
 #endif

libs/libc/wchar/lib_wmemcpy.c

@@ -55,6 +55,6 @@
 
 FAR wchar_t *wmemcpy(FAR wchar_t *d, FAR const wchar_t *s, size_t n)
 {
-  return (FAR wchar_t *)memcpy(d, s, n * sizeof(wchar_t));
+  return memcpy(d, s, n * sizeof(wchar_t));
 }
 #endif

libs/libc/wchar/lib_wmemmove.c

@@ -54,6 +54,6 @@
 
 FAR wchar_t *wmemmove(FAR wchar_t *d, FAR const wchar_t *s, size_t n)
 {
-  return (FAR wchar_t *)memmove(d, s, n * sizeof(wchar_t));
+  return memmove(d, s, n * sizeof(wchar_t));
 }
 #endif

libs/libc/wchar/lib_wmemset.c

@@ -57,7 +57,7 @@ FAR wchar_t *wmemset(FAR wchar_t *s, wchar_t c, size_t n)
   FAR wchar_t *p;
   size_t i;
 
-  p = (FAR wchar_t *)s;
+  p = s;
   for (i = 0; i < n; i++)
     {
       *p = c;