Reimplement sort method to reduce array copying.

mrbgems/mruby-enum-ext/mrblib/enum.rb

@@ -201,7 +201,7 @@ module Enumerable
       ary.push([block.call(e), i])
     }
     if ary.size > 1
-      __sort_sub__(ary, ::Array.new(ary.size), 0, 0, ary.size - 1) do |a,b|
+      __sort_sub__(ary, 0, ary.size - 1) do |a,b|
         a <=> b
       end
     end

mrblib/array.rb

@@ -1,3 +1,4 @@
+# coding: utf-8
 ##
 # Array
 #
@@ -192,10 +193,46 @@ class Array
   # ISO 15.2.12.3
   include Enumerable
 
+  ##
+  # Quick sort
+  # a     : the array to sort
+  # left  : the beginning of sort region
+  # right : the end of sort region
+  def __sort_sub__(a, left, right, &block)
+    if left < right
+      i = left
+      j = right
+      pivot = a[i + (j - i) / 2]
+      while true
+        while ((block)? block.call(a[i], pivot): (a[i] <=> pivot)) < 0
+          i += 1
+        end
+        while ((block)? block.call(pivot, a[j]): (pivot <=> a[j])) < 0
+          j -= 1
+        end
+        break if (i >= j)
+        tmp = a[i]; a[i] = a[j]; a[j] = tmp;
+        i += 1
+        j -= 1
+      end
+      __sort_sub__(a, left, i-1, &block)
+      __sort_sub__(a, j+1, right, &block)
+    end
+  end
+  #  private :__sort_sub__
+
   ##
   # Sort all elements and replace +self+ with these
   # elements.
   def sort!(&block)
-    self.replace(self.sort(&block))
+    size = self.size
+    if size > 1
+      __sort_sub__(self, 0, size - 1, &block)
+    end
+    self
+  end
+
+  def sort(&block)
+    self.dup.sort!(&block)
   end
 end

mrblib/enum.rb

@@ -315,45 +315,6 @@ module Enumerable
   # ISO 15.3.2.2.18
   alias select find_all
 
-  ##
-  # TODO
-  # Does this OK? Please test it.
-  def __sort_sub__(sorted, work, src_ary, head, tail, &block)
-    if head == tail
-      sorted[head] = work[head] if src_ary == 1
-      return
-    end
-
-    # on current step, which is a src ary?
-    if src_ary == 0
-      src, dst = sorted, work
-    else
-      src, dst = work, sorted
-    end
-
-    key = src[head]    # key value for dividing values
-    i, j = head, tail  # position to store on the dst ary
-
-    (head + 1).upto(tail){|idx|
-      if ((block)? block.call(src[idx], key): (src[idx] <=> key)) > 0
-        # larger than key
-        dst[j] = src[idx]
-        j -= 1
-      else
-        dst[i] = src[idx]
-        i += 1
-      end
-    }
-
-    sorted[i] = key
-
-    # sort each sub-array
-    src_ary = (src_ary + 1) % 2  # exchange a src ary
-    __sort_sub__(sorted, work, src_ary, head, i - 1, &block) if i > head
-    __sort_sub__(sorted, work, src_ary, i + 1, tail, &block) if i < tail
-  end
-#  private :__sort_sub__
-
   ##
   # Return a sorted array of all elements
   # which are yield by +each+. If no block
@@ -364,12 +325,7 @@ module Enumerable
   #
   # ISO 15.3.2.2.19
   def sort(&block)
-    ary = []
-    self.each{|*val| ary.push(val.__svalue)}
-    if ary.size > 1
-      __sort_sub__(ary, ::Array.new(ary.size), 0, 0, ary.size - 1, &block)
-    end
-    ary
+    self.map{|*val| val.__svalue}.sort
   end
 
   ##