[GR-59866] Add Range#overlap?

PullRequest: truffleruby/4451

CHANGELOG.md

@@ -49,6 +49,7 @@ Compatibility:
 * `Kernel#lambda` with now raises `ArgumentError` when given a non-lambda, non-literal block (#3681, @Th3-M4jor).
 * Add `rb_data_define()` to define Data (#3681, @andrykonchin).
 * Add `Refinement#target` (#3681, @andrykonchin).
+* Add `Range#overlap?` (#3681, @andrykonchin).
 
 Performance:
 

spec/ruby/core/range/overlap_spec.rb

@@ -0,0 +1,89 @@
+require_relative '../../spec_helper'
+
+ruby_version_is '3.3' do
+  describe "Range#overlap?" do
+    it "returns true if other Range overlaps self" do
+      (0..2).overlap?(1..3).should == true
+      (1..3).overlap?(0..2).should == true
+      (0..2).overlap?(0..2).should == true
+      (0..3).overlap?(1..2).should == true
+      (1..2).overlap?(0..3).should == true
+
+      ('a'..'c').overlap?('b'..'d').should == true
+    end
+
+    it "returns false if other Range does not overlap self" do
+      (0..2).overlap?(3..4).should == false
+      (0..2).overlap?(-4..-1).should == false
+
+      ('a'..'c').overlap?('d'..'f').should == false
+    end
+
+    it "raises TypeError when called with non-Range argument" do
+      -> {
+        (0..2).overlap?(1)
+      }.should raise_error(TypeError, "wrong argument type Integer (expected Range)")
+    end
+
+    it "returns true when beginningless and endless Ranges overlap" do
+      (0..2).overlap?(..3).should == true
+      (0..2).overlap?(..1).should == true
+      (0..2).overlap?(..0).should == true
+
+      (..3).overlap?(0..2).should == true
+      (..1).overlap?(0..2).should == true
+      (..0).overlap?(0..2).should == true
+
+      (0..2).overlap?(-1..).should == true
+      (0..2).overlap?(1..).should == true
+      (0..2).overlap?(2..).should == true
+
+      (-1..).overlap?(0..2).should == true
+      (1..).overlap?(0..2).should == true
+      (2..).overlap?(0..2).should == true
+
+      (0..).overlap?(2..).should == true
+      (..0).overlap?(..2).should == true
+    end
+
+    it "returns false when beginningless and endless Ranges do not overlap" do
+      (0..2).overlap?(..-1).should == false
+      (0..2).overlap?(3..).should == false
+
+      (..-1).overlap?(0..2).should == false
+      (3..).overlap?(0..2).should == false
+    end
+
+    it "returns false when Ranges are not compatible" do
+      (0..2).overlap?('a'..'d').should == false
+    end
+
+    it "return false when self is empty" do
+      (2..0).overlap?(1..3).should == false
+      (2...2).overlap?(1..3).should == false
+      (1...1).overlap?(1...1).should == false
+      (2..0).overlap?(2..0).should == false
+
+      ('c'..'a').overlap?('b'..'d').should == false
+      ('a'...'a').overlap?('b'..'d').should == false
+      ('b'...'b').overlap?('b'...'b').should == false
+      ('c'...'a').overlap?('c'...'a').should == false
+    end
+
+    it "return false when other Range is empty" do
+      (1..3).overlap?(2..0).should == false
+      (1..3).overlap?(2...2).should == false
+
+      ('b'..'d').overlap?('c'..'a').should == false
+      ('b'..'d').overlap?('c'...'c').should == false
+    end
+
+    it "takes into account exclusive end" do
+      (0...2).overlap?(2..4).should == false
+      (2..4).overlap?(0...2).should == false
+
+      ('a'...'c').overlap?('c'..'e').should == false
+      ('c'..'e').overlap?('a'...'c').should == false
+    end
+  end
+end

src/main/ruby/truffleruby/core/range.rb

@@ -442,6 +442,20 @@ def minmax(&block)
     end
   end
 
+  def overlap?(other)
+    Truffle::Type.rb_check_type(other, Range)
+
+    # ranges don't overlap
+    return false if Truffle::RangeOperations.greater_than?(self.begin, other.end, other.exclude_end?)
+    return false if Truffle::RangeOperations.greater_than?(other.begin, self.end, self.exclude_end?)
+
+    # empty range doesn't overlap any other range
+    return false if Truffle::RangeOperations.greater_than?(self.begin, self.end, self.exclude_end?)
+    return false if Truffle::RangeOperations.greater_than?(other.begin, other.end, other.exclude_end?)
+
+    true
+  end
+
   def %(n)
     Truffle::RangeOperations.step_no_block(self, n)
   end

src/main/ruby/truffleruby/core/truffle/range_operations.rb

@@ -138,5 +138,18 @@ def self.cover?(range, value)
 
       true
     end
+
+    # MRI: empty_region_p
+    def self.greater_than?(from, to, to_exclusive)
+      return false if Primitive.nil?(from)
+      return false if Primitive.nil?(to)
+
+      cmp = from <=> to
+
+      return true if Primitive.nil?(cmp)
+      return true if cmp == 0 && to_exclusive
+
+      cmp > 0 # that's from > to
+    end
   end
 end