--- a/libtommath/bn_mp_shrink.c	Tue May 26 23:27:26 2020 +0800
+++ b/libtommath/bn_mp_shrink.c	Tue May 26 17:36:47 2020 +0200
@@ -1,38 +1,22 @@
 #include "tommath_private.h"
 #ifdef BN_MP_SHRINK_C
-/* LibTomMath, multiple-precision integer library -- Tom St Denis
- *
- * LibTomMath is a library that provides multiple-precision
- * integer arithmetic as well as number theoretic functionality.
- *
- * The library was designed directly after the MPI library by
- * Michael Fromberger but has been written from scratch with
- * additional optimizations in place.
- *
- * SPDX-License-Identifier: Unlicense
- */
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
 
 /* shrink a bignum */
-int mp_shrink(mp_int *a)
+mp_err mp_shrink(mp_int *a)
 {
    mp_digit *tmp;
-   int used = 1;
-
-   if (a->used > 0) {
-      used = a->used;
-   }
-
-   if (a->alloc != used) {
-      if ((tmp = OPT_CAST(mp_digit) XREALLOC(a->dp, sizeof(mp_digit) * (size_t)used)) == NULL) {
+   int alloc = MP_MAX(MP_MIN_PREC, a->used);
+   if (a->alloc != alloc) {
+      if ((tmp = (mp_digit *) MP_REALLOC(a->dp,
+                                         (size_t)a->alloc * sizeof(mp_digit),
+                                         (size_t)alloc * sizeof(mp_digit))) == NULL) {
          return MP_MEM;
       }
       a->dp    = tmp;
-      a->alloc = used;
+      a->alloc = alloc;
    }
    return MP_OKAY;
 }
 #endif
-
-/* ref:         HEAD -> master, tag: v1.1.0 */
-/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
-/* commit time: 2019-01-28 20:32:32 +0100 */