Add String.byteslice with range arguments

Author: marcandre

lib/backports/3.3.0/string.rb

@@ -0,0 +1,3 @@
+require 'backports/tools/require_relative_dir'
+
+Backports.require_relative_dir

lib/backports/3.3.0/string/bytesplice.rb

@@ -0,0 +1,33 @@
+unless ("".bytesplice(0..0, "", 0..0) rescue false)
+  require 'backports/tools/alias_method_chain'
+
+  # Original API
+  #  *    bytesplice(index, length, str) -> string
+  #  *    bytesplice(range, str)         -> string
+
+  # Newly supported API:
+  #  *    bytesplice(index, length, str, str_index, str_length) -> string
+  #  *    bytesplice(range, str, str_range) -> string
+
+  class String
+    def bytesplice_with_range_replacement_support(*args)
+      case args.size
+      when 5
+        index, length, str, str_index, str_length = *args
+
+        str = str.byteslice(str_index, str_length) || (raise IndexError, "oops") # if str_index < -str.length
+        bytesplice_without_range_replacement_support(index, length, str)
+      when 3
+        if args[2].is_a?(Range)
+          str = args[1].byteslice(args[2]) || (raise RangeError, "oops")
+          bytesplice_without_range_replacement_support(args[0], str)
+        else
+          bytesplice_without_range_replacement_support(*args)
+        end
+      else
+        bytesplice_without_range_replacement_support(*args)
+      end
+    end
+    Backports.alias_method_chain self, :bytesplice, :range_replacement_support
+  end
+end

test/bytesplice_test.rb

@@ -0,0 +1,97 @@
+require './test/test_helper'
+require 'backports/3.3.0/string/bytesplice'
+
+class BytespliceTest < Test::Unit::TestCase
+  def test_bytesplice
+    assert_bytesplice_raise(IndexError, S("hello"), -6, 0, "bye")
+    assert_bytesplice_result("byehello", S("hello"), -5, 0, "bye")
+    assert_bytesplice_result("byehello", S("hello"), 0, 0, "bye")
+    assert_bytesplice_result("byeello", S("hello"), 0, 1, "bye")
+    assert_bytesplice_result("bye", S("hello"), 0, 5, "bye")
+    assert_bytesplice_result("bye", S("hello"), 0, 6, "bye")
+
+    assert_bytesplice_raise(IndexError, S("hello"), -5, 0, "bye", -4, 0)
+    assert_bytesplice_result("byehello", S("hello"), 0, 0, "bye", 0, 3)
+    assert_bytesplice_result("yehello", S("hello"), 0, 0, "bye", 1, 3)
+    assert_bytesplice_result("yehello", S("hello"), 0, 0, "bye", 1, 2)
+    assert_bytesplice_result("ehello", S("hello"), 0, 0, "bye", 2, 1)
+    assert_bytesplice_result("hello", S("hello"), 0, 0, "bye", 3, 0)
+    assert_bytesplice_result("hello", s = S("hello"), 0, 5, s, 0, 5)
+    assert_bytesplice_result("elloo", s = S("hello"), 0, 4, s, 1, 4)
+    assert_bytesplice_result("llolo", s = S("hello"), 0, 3, s, 2, 3)
+    assert_bytesplice_result("lollo", s = S("hello"), 0, 2, s, 3, 2)
+    assert_bytesplice_result("oello", s = S("hello"), 0, 1, s, 4, 1)
+    assert_bytesplice_result("hhell", s = S("hello"), 1, 4, s, 0, 4)
+    assert_bytesplice_result("hehel", s = S("hello"), 2, 3, s, 0, 3)
+    assert_bytesplice_result("helhe", s = S("hello"), 3, 2, s, 0, 2)
+    assert_bytesplice_result("hellh", s = S("hello"), 4, 1, s, 0, 1)
+
+    assert_bytesplice_raise(RangeError, S("hello"), -6...-6, "bye")
+    assert_bytesplice_result("byehello", S("hello"), -5...-5, "bye")
+    assert_bytesplice_result("byehello", S("hello"), 0...0, "bye")
+    assert_bytesplice_result("byeello", S("hello"), 0..0, "bye")
+    assert_bytesplice_result("byeello", S("hello"), 0...1, "bye")
+    assert_bytesplice_result("byello", S("hello"), 0..1, "bye")
+    assert_bytesplice_result("bye", S("hello"), 0..-1, "bye")
+    assert_bytesplice_result("bye", S("hello"), 0...5, "bye")
+    assert_bytesplice_result("bye", S("hello"), 0...6, "bye")
+    assert_bytesplice_result("llolo", s = S("hello"), 0..2, s, 2..4)
+
+    assert_bytesplice_raise(RangeError, S("hello"), -5...-5, "bye", -6...-6)
+    assert_bytesplice_result("byehello", S("hello"), -5...-5, "bye", 0..-1)
+    assert_bytesplice_result("byehello", S("hello"), 0...0, "bye", 0..-1)
+    assert_bytesplice_result("bhello", S("hello"), 0...0, "bye", 0..0)
+    assert_bytesplice_result("byhello", S("hello"), 0...0, "bye", 0..1)
+    assert_bytesplice_result("byehello", S("hello"), 0...0, "bye", 0..2)
+    assert_bytesplice_result("yehello", S("hello"), 0...0, "bye", 1..2)
+
+    assert_bytesplice_raise(TypeError, S("hello"), 0, "bye")
+
+    assert_bytesplice_raise(IndexError, S("こんにちは"), -16, 0, "bye")
+    assert_bytesplice_result("byeこんにちは", S("こんにちは"), -15, 0, "bye")
+    assert_bytesplice_result("byeこんにちは", S("こんにちは"), 0, 0, "bye")
+    assert_bytesplice_raise(IndexError, S("こんにちは"), 1, 0, "bye")
+    assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 1, "bye")
+    assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 2, "bye")
+    assert_bytesplice_result("byeんにちは", S("こんにちは"), 0, 3, "bye")
+    assert_bytesplice_result("こんにちはbye", S("こんにちは"), 15, 0, "bye")
+
+    assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 0, "さようなら", -16, 0)
+    assert_bytesplice_result("こんにちはさようなら", S("こんにちは"), 15, 0, "さようなら", 0, 15)
+    assert_bytesplice_result("さようなら", S("こんにちは"), 0, 15, "さようなら", 0, 15)
+    assert_bytesplice_result("さんにちは", S("こんにちは"), 0, 3, "さようなら", 0, 3)
+    assert_bytesplice_result("さようちは", S("こんにちは"), 0, 9, "さようなら", 0, 9)
+    assert_bytesplice_result("ようなちは", S("こんにちは"), 0, 9, "さようなら", 3, 9)
+    assert_bytesplice_result("ようちは", S("こんにちは"), 0, 9, "さようなら", 3, 6)
+    assert_bytesplice_result("ようならちは", S("こんにちは"), 0, 9, "さようなら", 3, 12)
+    assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 15, "さようなら", -16, 0)
+    # assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 15, "さようなら", 1, 0)
+    # assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 15, "さようなら", 2, 0)
+    # assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 15, "さようなら", 0, 1)
+    # assert_bytesplice_raise(IndexError, S("こんにちは"), 0, 15, "さようなら", 0, 2)
+    assert_bytesplice_result("にちはちは", s = S("こんにちは"), 0, 9, s, 6, 9)
+
+    assert_bytesplice_result("", S(""), 0, 0, "")
+    assert_bytesplice_result("xxx", S(""), 0, 0, "xxx")
+
+    assert_bytesplice_raise(ArgumentError, S("hello"), 0, 5, "bye", 0)
+    assert_bytesplice_raise(ArgumentError, S("hello"), 0, 5, "bye", 0..-1)
+    assert_bytesplice_raise(ArgumentError, S("hello"), 0..-1, "bye", 0, 3)
+  end
+
+  private
+
+  def assert_bytesplice_result(expected, s, *args)
+    assert_equal(expected, s.send(:bytesplice, *args))
+    assert_equal(expected, s)
+  end
+
+  def assert_bytesplice_raise(e, s, *args)
+    assert_raise(e) { s.send(:bytesplice, *args) }
+  end
+
+  def S(*args, **kw)
+    String.new(*args, **kw)
+  end
+
+end