# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1489155652 -3600
# Node ID a0c610ee056232776060d12e6f69f15ab5166e97
# Parent  e1c5d2360c5ce9fc16d09f0fb57a03e1a8c05489
Make xrange iteration more efficient by only testing an updated counter when
obtaining each new value instead of testing if the value is within the range.

diff -r e1c5d2360c5c -r a0c610ee0562 lib/__builtins__/span.py
--- a/lib/__builtins__/span.py	Thu Mar 09 23:19:43 2017 +0100
+++ b/lib/__builtins__/span.py	Fri Mar 10 15:20:52 2017 +0100
@@ -90,7 +90,7 @@
         "Initialise the iterator with the given 'obj'."
 
         self.start = obj.start
-        self.end = obj.end
+        self.count = obj.__len__()
         self.step = obj.step
         self.current = obj.start
 
@@ -98,11 +98,12 @@
 
         "Return the next item or raise a StopIteration exception."
 
-        if self.step < 0 and self.current <= self.end or self.step > 0 and self.current >= self.end:
+        if not self.count:
             raise StopIteration
 
         current = self.current
         self.current += self.step
+        self.count -= 1
         return current
 
 def range(start_or_end, end=None, step=1):