Import code from previous AssetBuilder version

thirdparty/libtommath/bn_mp_grow.c

@@ -0,0 +1,54 @@
+#include "tommath_private.h"
+#ifdef BN_MP_GROW_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
+ */
+
+/* grow as required */
+int mp_grow(mp_int *a, int size)
+{
+   int     i;
+   mp_digit *tmp;
+
+   /* if the alloc size is smaller alloc more ram */
+   if (a->alloc < size) {
+      /* ensure there are always at least MP_PREC digits extra on top */
+      size += (MP_PREC * 2) - (size % MP_PREC);
+
+      /* reallocate the array a->dp
+       *
+       * We store the return in a temporary variable
+       * in case the operation failed we don't want
+       * to overwrite the dp member of a.
+       */
+      tmp = OPT_CAST(mp_digit) XREALLOC(a->dp, sizeof(mp_digit) * (size_t)size);
+      if (tmp == NULL) {
+         /* reallocation failed but "a" is still valid [can be freed] */
+         return MP_MEM;
+      }
+
+      /* reallocation succeeded so set a->dp */
+      a->dp = tmp;
+
+      /* zero excess digits */
+      i        = a->alloc;
+      a->alloc = size;
+      for (; i < a->alloc; i++) {
+         a->dp[i] = 0;
+      }
+   }
+   return MP_OKAY;
+}
+#endif
+
+/* ref:         HEAD -> master, tag: v1.1.0 */
+/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
+/* commit time: 2019-01-28 20:32:32 +0100 */