1 files changed, 70 insertions, 0 deletions
diff --git a/src/bignum.h b/src/bignum.h
new file mode 100644
index 00000000000..a368333d77e
--- /dev/null
+++ b/src/bignum.h
@@ -0,0 +1,70 @@
+/* Big numbers for Emacs.
+
+Copyright 2018 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Include this header only if access to bignum internals is needed.  */
+
+#ifndef BIGNUM_H
+#define BIGNUM_H
+
+#ifdef HAVE_GMP
+# include <gmp.h>
+#else
+# include "mini-gmp.h"
+#endif
+
+#include "lisp.h"
+
+/* Number of data bits in a limb.  */
+#ifndef GMP_NUMB_BITS
+enum { GMP_NUMB_BITS = TYPE_WIDTH (mp_limb_t) };
+#endif
+
+struct Lisp_Bignum
+{
+  union vectorlike_header header;
+  mpz_t value;
+};
+
+extern Lisp_Object make_integer (mpz_t const) ARG_NONNULL ((1));
+extern void mpz_set_intmax_slow (mpz_t, intmax_t) ARG_NONNULL ((1));
+
+INLINE_HEADER_BEGIN
+
+INLINE struct Lisp_Bignum *
+XBIGNUM (Lisp_Object a)
+{
+  eassert (BIGNUMP (a));
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Bignum);
+}
+
+INLINE void ARG_NONNULL ((1))
+mpz_set_intmax (mpz_t result, intmax_t v)
+{
+  /* mpz_set_si works in terms of long, but Emacs may use a wider
+     integer type, and so sometimes will have to construct the mpz_t
+     by hand.  */
+  if (LONG_MIN <= v && v <= LONG_MAX)
+    mpz_set_si (result, v);
+  else
+    mpz_set_intmax_slow (result, v);
+}
+
+INLINE_HEADER_END
+
+#endif /* BIGNUM_H */