Add rb_arithmetic_sequence_beg_len_step function

Author: andrykonchin

optional/capi/ext/range_spec.c

@@ -38,11 +38,49 @@ VALUE range_spec_rb_range_beg_len(VALUE self, VALUE range, VALUE begpv, VALUE le
   return ary;
 }
 
+VALUE range_spec_rb_arithmetic_sequence_extract(VALUE self, VALUE object) {
+  VALUE ary = rb_ary_new();
+  rb_arithmetic_sequence_components_t components;
+
+  int status = rb_arithmetic_sequence_extract(object, &components);
+
+  if (!status) {
+      rb_ary_store(ary, 0, LONG2FIX(status));
+      return ary;
+  }
+
+  rb_ary_store(ary, 0, LONG2FIX(status));
+  rb_ary_store(ary, 1, components.begin);
+  rb_ary_store(ary, 2, components.end);
+  rb_ary_store(ary, 3, components.step);
+  rb_ary_store(ary, 4, components.exclude_end ? Qtrue : Qfalse);
+  return ary;
+}
+
+VALUE range_spec_rb_arithmetic_sequence_beg_len_step(VALUE self, VALUE aseq, VALUE lenv, VALUE errv) {
+  long begp, lenp, stepp;
+
+  long len = FIX2LONG(lenv);
+  int err = FIX2INT(errv);
+
+  VALUE success = rb_arithmetic_sequence_beg_len_step(aseq, &begp, &lenp, &stepp, len, err);
+
+  VALUE ary = rb_ary_new();
+  rb_ary_store(ary, 0, success);
+  rb_ary_store(ary, 1, LONG2FIX(begp));
+  rb_ary_store(ary, 2, LONG2FIX(lenp));
+  rb_ary_store(ary, 3, LONG2FIX(stepp));
+
+  return ary;
+}
+
 void Init_range_spec(void) {
   VALUE cls = rb_define_class("CApiRangeSpecs", rb_cObject);
   rb_define_method(cls, "rb_range_new", range_spec_rb_range_new, -1);
   rb_define_method(cls, "rb_range_values", range_spec_rb_range_values, 1);
   rb_define_method(cls, "rb_range_beg_len", range_spec_rb_range_beg_len, 5);
+  rb_define_method(cls, "rb_arithmetic_sequence_extract", range_spec_rb_arithmetic_sequence_extract, 1);
+  rb_define_method(cls, "rb_arithmetic_sequence_beg_len_step", range_spec_rb_arithmetic_sequence_beg_len_step, 3);
 }
 
 #ifdef __cplusplus

optional/capi/range_spec.rb

@@ -92,4 +92,140 @@ def range_like.exclude_end?
       result.should be_nil
     end
   end
+
+  describe "rb_arithmetic_sequence_extract" do
+    it "returns begin, end, step, exclude end of an instance of an Enumerator::ArithmeticSequence" do
+      enum = (10..20).step(5)
+      enum.should.kind_of?(Enumerator::ArithmeticSequence)
+
+      @s.rb_arithmetic_sequence_extract(enum).should == [1, 10, 20, 5, false]
+    end
+
+    it "returns begin, end, step, exclude end of an instance of a Range" do
+      range = (10..20)
+      @s.rb_arithmetic_sequence_extract(range).should == [1, 10, 20, 1, false]
+    end
+
+    it "returns begin, end, step, exclude end of a non-Range object with Range properties" do
+      object = Object.new
+      def object.begin
+        10
+      end
+      def object.end
+        20
+      end
+      def object.exclude_end?
+        false
+      end
+
+      @s.rb_arithmetic_sequence_extract(object).should == [1, 10, 20, 1, false]
+    end
+
+    it "returns failed status if given object is not Enumerator::ArithmeticSequence or Range or Range-like object" do
+      object = Object.new
+      @s.rb_arithmetic_sequence_extract(object).should == [0]
+    end
+  end
+
+  describe "rb_arithmetic_sequence_beg_len_step" do
+    it "returns correct begin, length, step and result" do
+      as = (2..5).step(5)
+      error_code = 0
+
+      success, beg, len, step = @s.rb_arithmetic_sequence_beg_len_step(as, 6, error_code)
+      success.should be_true
+
+      beg.should == 2
+      len.should == 4
+      step.should == 5
+    end
+
+    it "takes into account excluded end boundary" do
+      as = (2...5).step(1)
+      error_code = 0
+
+      success, _, len, _ = @s.rb_arithmetic_sequence_beg_len_step(as, 6, error_code)
+      success.should be_true
+      len.should == 3
+    end
+
+    it "adds length to negative begin boundary" do
+      as = (-2..5).step(1)
+      error_code = 0
+
+      success, beg, len, _ = @s.rb_arithmetic_sequence_beg_len_step(as, 6, error_code)
+      success.should be_true
+
+      beg.should == 4
+      len.should == 2
+    end
+
+    it "adds length to negative end boundary" do
+      as = (2..-1).step(1)
+      error_code = 0
+
+      success, beg, len, _ = @s.rb_arithmetic_sequence_beg_len_step(as, 6, error_code)
+      success.should be_true
+
+      beg.should == 2
+      len.should == 4
+    end
+
+    it "truncates arithmetic sequence length if end boundary greater than specified length value" do
+      as = (2..10).step(1)
+      error_code = 0
+
+      success, _, len, _ = @s.rb_arithmetic_sequence_beg_len_step(as, 6, error_code)
+      success.should be_true
+      len.should == 4
+    end
+
+    it "returns inverted begin and end boundaries when step is negative" do
+      as = (2..5).step(-2)
+      error_code = 0
+
+      success, beg, len, step = @s.rb_arithmetic_sequence_beg_len_step(as, 6, error_code)
+      success.should be_true
+
+      beg.should == 5
+      len.should == 0
+      step.should == -2
+    end
+
+    it "returns nil when not in range and error code = 0" do
+      as = (2..5).step(1)
+      error_code = 0
+
+      success, = @s.rb_arithmetic_sequence_beg_len_step(as, 1, error_code)
+      success.should be_nil
+    end
+
+    it "returns nil when not in range, negative boundaries and error code = 0" do
+      as = (-5..-1).step(1)
+      error_code = 0
+
+      success, = @s.rb_arithmetic_sequence_beg_len_step(as, 1, 0)
+      success.should be_nil
+    end
+
+    it "returns begin, length and step and doesn't raise a RangeError when not in range and error code = 1" do
+      as = (2..5).step(1)
+      error_code = 1
+
+      success, beg, len, step = @s.rb_arithmetic_sequence_beg_len_step(as, 1, error_code)
+      success.should be_true
+
+      beg.should == 2
+      len.should == 4
+      step.should == 1
+    end
+
+    it "returns nil and doesn't raise a RangeError when not in range, negative boundaries and error code = 1" do
+      as = (-5..-1).step(1)
+      error_code = 1
+
+      success, = @s.rb_arithmetic_sequence_beg_len_step(as, 1, error_code)
+      success.should be_nil
+    end
+  end
 end