[GR-18163] Fix Integer#digits to handle more bases

PullRequest: truffleruby/2335

Author: bjfish

CHANGELOG.md

@@ -39,6 +39,7 @@ Compatibility:
 * Switched to the io-console C extension from C ruby for better performance and compatibility in `irb`.
 * Coerce the message to a `String` for `BasicSocket#send` (#2209, @HoneyryderChuck).
 * Support buffer argument for `UDPSocket#recvfrom_nonblock` (#2209, @HoneyryderChuck).
+* Fixed `Integer#digits` implementation to handle more bases (#2224, #2225).
 
 Performance:
 

spec/ruby/core/integer/digits_spec.rb

@@ -29,4 +29,13 @@
   it "raises Math::DomainError when calling digits on a negative number" do
     -> { -12345.digits(7) }.should raise_error(Math::DomainError)
   end
+
+  it "returns integer values > 9 when base is above 10" do
+    1234.digits(16).should == [2, 13, 4]
+  end
+
+  it "can be used with base > 37" do
+    1234.digits(100).should == [34, 12]
+    980099.digits(100).should == [99, 0, 98]
+  end
 end

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

@@ -314,8 +314,17 @@ def pred
   def digits(base = 10)
     raise Math::DomainError, 'out of domain' if negative?
     base = Primitive.rb_to_int(base)
-
-    to_s(base).chars.map(&:to_i).reverse
+    raise ArgumentError, 'negative radix' if base < 0
+    raise ArgumentError, "invalid radix #{base}" if base < 2
+    return [0] if self == 0
+
+    result = []
+    x = self
+    while x > 0
+      result << x % base
+      x /= base
+    end
+    result
   end
 
   def self.sqrt(n)

test/mri/excludes/TestInteger.rb

@@ -1,13 +1,11 @@
 exclude :test_Integer, "needs investigation"
-exclude :test_digits_for_non_integral_base_numbers, "needs investigation"
 exclude :test_round, "needs investigation"
 exclude :test_square_root, "needs investigation"
 exclude :test_Integer_with_exception_keyword, "needs investigation"
 exclude :test_bitwise_and_with_integer_coercion, "needs investigation"
 exclude :test_bitwise_or_with_integer_coercion, "needs investigation"
 exclude :test_bitwise_xor_with_integer_coercion, "needs investigation"
 exclude :test_ceil, "needs investigation"
-exclude :test_digits, "needs investigation"
 exclude :test_floor, "needs investigation"
 exclude :test_pow, "needs investigation"
 exclude :test_truncate, "needs investigation"