From: Tom Tromey <tom@tromey.com>
Date: Sat, 7 Jul 2018 20:22:44 +0000 (-0600)
Subject: Make logcount handle bignums
X-Git-Tag: emacs-27.0.90~4598^2~25
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=a770fb44288c75fa2b0471ceaf00bf741376e40f;p=emacs.git

Make logcount handle bignums

* src/data.c (Flogcount): Handle bignums.
* test/src/data-tests.el (data-tests-logcount): New test.
---

diff --git a/src/data.c b/src/data.c
index c9504694e37..2e366b5313f 100644
--- a/src/data.c
+++ b/src/data.c
@@ -3184,7 +3184,22 @@ of VALUE.  If VALUE is negative, return the number of zero bits in the
 representation.  */)
   (Lisp_Object value)
 {
-  CHECK_FIXNUM (value);
+  CHECK_INTEGER (value);
+
+  if (BIGNUMP (value))
+    {
+      if (mpz_cmp_si (XBIGNUM (value)->value, 0) >= 0)
+	return make_fixnum (mpz_popcount (XBIGNUM (value)->value));
+      mpz_t tem;
+      mpz_init (tem);
+      mpz_neg (tem, XBIGNUM (value)->value);
+      mpz_sub_ui (tem, tem, 1);
+      Lisp_Object result = make_fixnum (mpz_popcount (tem));
+      mpz_clear (tem);
+      return result;
+    }
+
+  eassume (FIXNUMP (value));
   EMACS_INT v = XINT (value) < 0 ? -1 - XINT (value) : XINT (value);
   return make_fixnum (EMACS_UINT_WIDTH <= UINT_WIDTH
 		      ? count_one_bits (v)
diff --git a/test/src/data-tests.el b/test/src/data-tests.el
index dd6ce196f96..561b7bd9ca6 100644
--- a/test/src/data-tests.el
+++ b/test/src/data-tests.el
@@ -587,4 +587,7 @@ comparing the subr with a much slower lisp implementation."
   (should (< (1- most-negative-fixnum) most-negative-fixnum))
   (should (fixnump (1- (1+ most-positive-fixnum)))))
 
+(ert-deftest data-tests-logcount ()
+  (should (= (logcount (read "#xffffffffffffffffffffffffffffffff")) 128)))
+
 ;;; data-tests.el ends here