Import code from previous AssetBuilder version

thirdparty/libtommath/bn_mp_copy.c

@@ -0,0 +1,64 @@
+#include "tommath_private.h"
+#ifdef BN_MP_COPY_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
+ */
+
+/* copy, b = a */
+int mp_copy(const mp_int *a, mp_int *b)
+{
+   int     res, n;
+
+   /* if dst == src do nothing */
+   if (a == b) {
+      return MP_OKAY;
+   }
+
+   /* grow dest */
+   if (b->alloc < a->used) {
+      if ((res = mp_grow(b, a->used)) != MP_OKAY) {
+         return res;
+      }
+   }
+
+   /* zero b and copy the parameters over */
+   {
+      mp_digit *tmpa, *tmpb;
+
+      /* pointer aliases */
+
+      /* source */
+      tmpa = a->dp;
+
+      /* destination */
+      tmpb = b->dp;
+
+      /* copy all the digits */
+      for (n = 0; n < a->used; n++) {
+         *tmpb++ = *tmpa++;
+      }
+
+      /* clear high digits */
+      for (; n < b->used; n++) {
+         *tmpb++ = 0;
+      }
+   }
+
+   /* copy used count and sign */
+   b->used = a->used;
+   b->sign = a->sign;
+   return MP_OKAY;
+}
+#endif
+
+/* ref:         HEAD -> master, tag: v1.1.0 */
+/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
+/* commit time: 2019-01-28 20:32:32 +0100 */