added tohexstring() builtin

src/ruby/ycp/builtins.rb

@@ -837,8 +837,30 @@ def self.toascii
     # Converts an integer to a hexadecimal string.
     # - tohexstring(<int>)
     # - tohexstring(<int>, <int>width)
-    def self.tohexstring
-      raise "Builtin tohexstring() is not implemented yet"
+    def self.tohexstring int, width = 0
+      return nil if int.nil? || width.nil?
+
+      if int >= 0
+        sprintf("0x%0#{width}x", int)
+      else
+        # compatibility for negative numbers
+        # Ruby: -3 => '0x..fd'
+        # YCP:  -3 => '0xfffffffffffffffd' (64bit integer)
+
+        # this has '..fff' prefix
+        ret = sprintf("%018x", int)
+
+        # pad with zeroes or spaces if needed
+        if width > 16
+          ret.insert(2, "0" * (width - 16))
+        elsif width < -16
+          ret << (" " * (-width - 16))
+        end
+
+        # replace the ".." prefix by "0x"
+        ret[0..1] = "0x"
+        ret
+      end
     end
 
     # tolower() YCP built-in

tests/ruby/builtins_test.rb

@@ -152,6 +152,32 @@ def test_regexptokenize
     assert_equal nil, YCP::Builtins.regexptokenize("aaabbb", "(.*ba).*(");
   end
 
+  def test_tohexstring
+    assert_equal nil, YCP::Builtins.tohexstring(nil)
+    assert_equal nil, YCP::Builtins.tohexstring(nil, nil)
+    assert_equal "0x0", YCP::Builtins.tohexstring(0)
+    assert_equal "0xa", YCP::Builtins.tohexstring(10)
+    assert_equal "0xff", YCP::Builtins.tohexstring(255)
+    assert_equal "0x3640e", YCP::Builtins.tohexstring(222222)
+
+    assert_equal "0x1f", YCP::Builtins.tohexstring(31, 0)
+    assert_equal "0x1f", YCP::Builtins.tohexstring(31, 1)
+    assert_equal "0x001f", YCP::Builtins.tohexstring(31, 4)
+    assert_equal "0x00001f", YCP::Builtins.tohexstring(31, 6)
+
+    assert_equal "0x1f", YCP::Builtins.tohexstring(31, -1)
+    assert_equal "0x1f ", YCP::Builtins.tohexstring(31, -3)
+
+    assert_equal "0xfffffffffffffffd", YCP::Builtins.tohexstring(-3)
+    assert_equal "0xfffffffffffffffd", YCP::Builtins.tohexstring(-3, 5)
+    assert_equal "0x00fffffffffffffffd", YCP::Builtins.tohexstring(-3, 18)
+    assert_equal "0x000000fffffffffffffffd", YCP::Builtins.tohexstring(-3, 22)
+
+    assert_equal "0xfffffffffffffffd", YCP::Builtins.tohexstring(-3, -16)
+    assert_equal "0xfffffffffffffffd ", YCP::Builtins.tohexstring(-3, -17)
+    assert_equal "0xfffffffffffffffd      ", YCP::Builtins.tohexstring(-3, -22)
+  end
+
   def test_tolower
     assert_equal nil, YCP::Builtins.tolower(nil)
     assert_equal "", YCP::Builtins.tolower("")