Optimize String#each_line
MODIFY
mrblib/string.rb
mrblib/string.rb
@@ -11,7 +11,7 @@ class String
# and pass the respective line.
#
# ISO 15.2.10.5.15
- def each_line(separator = "\n", getline_args = nil)
+ def each_line(separator = "\n")
return to_enum(:each_line, separator, getline_args) unless block_given?
if separator.nil?
@@ -20,22 +20,25 @@ class String
end
raise TypeError unless separator.is_a?(String)
- start = 0
pointer = 0
+ start = 0
string = dup
+ self_len = length
+ sep_len = separator.length
+ should_yield_subclass_instances = self.class != String
if separator.empty?
matched_newlines = 0
- while pointer < string.length
+ while pointer < self_len
c = string[pointer]
if c == "\n"
matched_newlines += 1
- elsif matched_newlines > 1 && self.class == String
- yield string[start...pointer]
+ elsif matched_newlines > 1 && should_yield_subclass_instances
+ yield self.class.new(string[start, pointer - start])
matched_newlines = 0
start = pointer
elsif matched_newlines > 1
- yield self.class.new(string[start...pointer])
+ yield string[start, pointer - start]
matched_newlines = 0
start = pointer
else
@@ -45,21 +48,21 @@ class String
end
else
while (pointer = string.index(separator, start))
- pointer += separator.length
- if self.class == String
- yield string[start...pointer]
+ pointer += sep_len
+ if should_yield_subclass_instances
+ yield self.class.new(string[start, pointer - start])
else
- yield self.class.new(string[start...pointer])
+ yield string[start, pointer - start]
end
start = pointer
end
end
- return self if start == string.length
+ return self if start == self_len
- if self.class == String
- yield string[start..-1]
+ if should_yield_subclass_instances
+ yield self.class.new(string[start, self_len - start])
else
- yield self.class.new(string[start..-1])
+ yield string[start, self_len - start]
end
self
end

Optimize String#each_line