[macruby-changes] [2023] MacRuby/branches/experimental

[source_changes at macosforge.org]

Revision: 2023
          http://trac.macosforge.org/projects/ruby/changeset/2023
Author:   pthomson at apple.com
Date:     2009-07-14 16:48:55 -0700 (Tue, 14 Jul 2009)
Log Message:
-----------
Implemented Fixnum#popcnt, a MacRuby extension to Fixnum that counts the number of set bits in a number.

Modified Paths:
--------------
    MacRuby/branches/experimental/numeric.c
    MacRuby/branches/experimental/spec/macruby/core/number_spec.rb

Modified: MacRuby/branches/experimental/numeric.c
===================================================================
--- MacRuby/branches/experimental/numeric.c	2009-07-14 20:14:45 UTC (rev 2022)
+++ MacRuby/branches/experimental/numeric.c	2009-07-14 23:48:55 UTC (rev 2023)
@@ -3113,6 +3113,12 @@
     return Qfalse;
 }
 
+static VALUE
+fix_popcnt(VALUE num, SEL sel)
+{
+	return INT2FIX(__builtin_popcountl(FIX2ULONG(num)));
+}
+
 /*
  *  call-seq:
  *     fix.odd? -> true or false
@@ -3339,6 +3345,7 @@
     rb_objc_define_method(rb_cFixnum, "odd?", fix_odd_p, 0);
     rb_objc_define_method(rb_cFixnum, "even?", fix_even_p, 0);
     rb_objc_define_method(rb_cFixnum, "succ", fix_succ, 0);
+	rb_objc_define_method(rb_cFixnum, "popcnt", fix_popcnt, 0);
 
     rb_cFloat  = rb_define_class("Float", rb_cNumeric);
 

Modified: MacRuby/branches/experimental/spec/macruby/core/number_spec.rb
===================================================================
--- MacRuby/branches/experimental/spec/macruby/core/number_spec.rb	2009-07-14 20:14:45 UTC (rev 2022)
+++ MacRuby/branches/experimental/spec/macruby/core/number_spec.rb	2009-07-14 23:48:55 UTC (rev 2023)
@@ -10,3 +10,13 @@
 end
 
 # TODO cover the Numeric interface on top of NSNumber
+
+describe "Fixnum#popcnt" do
+	it "counts the number of set bits in a number" do
+		5.popcnt.should == 2
+		0.popcnt.should == 0
+		1024.popcnt.should == 1
+		# popcnt can, and should, vary depending on machine word size for negative numbers.
+		-1.popcnt.should <= 64
+	end
+end
\ No newline at end of file
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