Make 1+ and 1- handle bignums

* src/data.c (Fadd1, Fsub1): Handle bignums.
* test/src/data-tests.el (data-tests-1+, data-tests-1-): New tests.

2 files changed, 52 insertions, 4 deletions

diff --git a/src/data.c b/src/data.c
index 18b572de977..d7175683c89 100644
--- a/src/data.c
+++ b/src/data.c
@@ -3239,12 +3239,32 @@ DEFUN ("1+", Fadd1, Sadd1, 1, 1, 0,
 Markers are converted to integers.  */)
   (register Lisp_Object number)
 {
-  CHECK_FIXNUM_OR_FLOAT_COERCE_MARKER (number);
+  CHECK_NUMBER_COERCE_MARKER (number);
 
   if (FLOATP (number))
     return (make_float (1.0 + XFLOAT_DATA (number)));
 
-  XSETINT (number, XINT (number) + 1);
+  if (BIGNUMP (number))
+    {
+      mpz_t num;
+      mpz_init (num);
+      mpz_add_ui (num, XBIGNUM (number)->value, 1);
+      number = make_number (num);
+      mpz_clear (num);
+    }
+  else
+    {
+      eassume (FIXNUMP (number));
+      if (XINT (number) < MOST_POSITIVE_FIXNUM)
+        XSETINT (number, XINT (number) + 1);
+      else
+        {
+          mpz_t num;
+          mpz_init_set_si (num, XINT (number) + 1);
+          number = make_number (num);
+          mpz_clear (num);
+        }
+    }
   return number;
 }
 
@@ -3253,12 +3273,32 @@ DEFUN ("1-", Fsub1, Ssub1, 1, 1, 0,
 Markers are converted to integers.  */)
   (register Lisp_Object number)
 {
-  CHECK_FIXNUM_OR_FLOAT_COERCE_MARKER (number);
+  CHECK_NUMBER_COERCE_MARKER (number);
 
   if (FLOATP (number))
     return (make_float (-1.0 + XFLOAT_DATA (number)));
 
-  XSETINT (number, XINT (number) - 1);
+  if (BIGNUMP (number))
+    {
+      mpz_t num;
+      mpz_init (num);
+      mpz_sub_ui (num, XBIGNUM (number)->value, 1);
+      number = make_number (num);
+      mpz_clear (num);
+    }
+  else
+    {
+      eassume (FIXNUMP (number));
+      if (XINT (number) > MOST_POSITIVE_FIXNUM)
+        XSETINT (number, XINT (number) - 1);
+      else
+        {
+          mpz_t num;
+          mpz_init_set_si (num, XINT (number) - 1);
+          number = make_number (num);
+          mpz_clear (num);
+        }
+    }
   return number;
 }
 
diff --git a/test/src/data-tests.el b/test/src/data-tests.el
index 1143028a126..dd6ce196f96 100644
--- a/test/src/data-tests.el
+++ b/test/src/data-tests.el
@@ -579,4 +579,12 @@ comparing the subr with a much slower lisp implementation."
          (v (read s)))
     (should (equal (number-to-string v) s))))
 
+(ert-deftest data-tests-1+ ()
+  (should (> (1+ most-positive-fixnum) most-positive-fixnum))
+  (should (fixnump (1+ (1- most-negative-fixnum)))))
+
+(ert-deftest data-tests-1- ()
+  (should (< (1- most-negative-fixnum) most-negative-fixnum))
+  (should (fixnump (1- (1+ most-positive-fixnum)))))
+
 ;;; data-tests.el ends here