From b2f3f4ee29ba8510d3cad8025d9ce2c2014b1b7f Mon Sep 17 00:00:00 2001
From: Tom Tromey <tom@tromey.com>
Date: Sat, 7 Jul 2018 14:53:23 -0600
Subject: [PATCH] Provide new functions to create bignums

* src/alloc.c (make_bignum_str, make_number): New functions.
* src/lisp.h (make_bignum_str, make_number): Declare.
---
 src/alloc.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 src/lisp.h  |  3 +++
 2 files changed, 48 insertions(+)

diff --git a/src/alloc.c b/src/alloc.c
index 8ebf3e05d69..b775948fd96 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3779,6 +3779,51 @@ build_marker (struct buffer *buf, ptrdiff_t charpos, ptrdiff_t bytepos)
   return obj;
 }
 
+
+
+Lisp_Object
+make_bignum_str (const char *num, int base)
+{
+  Lisp_Object obj;
+  struct Lisp_Bignum *b;
+  int check;
+
+  obj = allocate_misc (Lisp_Misc_Bignum);
+  b = XBIGNUM (obj);
+  mpz_init (b->value);
+  check = mpz_set_str (b->value, num, base);
+  eassert (check == 0);
+  return obj;
+}
+
+/* Given an mpz_t, make a number.  This may return a bignum or a
+   fixnum depending on VALUE.  */
+
+Lisp_Object
+make_number (mpz_t value)
+{
+  Lisp_Object obj;
+  struct Lisp_Bignum *b;
+
+  if (mpz_fits_slong_p (value))
+    {
+      long l = mpz_get_si (value);
+      if (!FIXNUM_OVERFLOW_P (l))
+	{
+	  XSETINT (obj, l);
+	  return obj;
+	}
+    }
+
+  obj = allocate_misc (Lisp_Misc_Bignum);
+  b = XBIGNUM (obj);
+  /* We could mpz_init + mpz_swap here, to avoid a copy, but the
+     resulting API seemed possibly confusing.  */
+  mpz_init_set (b->value, value);
+
+  return obj;
+}
+
 
 /* Return a newly created vector or string with specified arguments as
    elements.  If all the arguments are characters that can fit
diff --git a/src/lisp.h b/src/lisp.h
index 37e43b0c5a1..6a3db24949a 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3643,6 +3643,9 @@ extern Lisp_Object list5 (Lisp_Object, Lisp_Object, Lisp_Object, Lisp_Object,
 enum constype {CONSTYPE_HEAP, CONSTYPE_PURE};
 extern Lisp_Object listn (enum constype, ptrdiff_t, Lisp_Object, ...);
 
+extern Lisp_Object make_bignum_str (const char *num, int base);
+extern Lisp_Object make_number (mpz_t value);
+
 /* Build a frequently used 2/3/4-integer lists.  */
 
 INLINE Lisp_Object
-- 
2.39.2