From 81da4cd39d67db53ea95c6ddb5855e050a3f4391 Mon Sep 17 00:00:00 2001
From: Bernard Blackham <dagobah@ucc.asn.au>
Date: Fri, 6 May 2005 11:41:34 +0000
Subject: [PATCH] Remove vending machine bootup time. Generate permutation in a
 smarter fashion.

---
 sql-edition/servers/Idler.py | 55 +++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 23 deletions(-)

diff --git a/sql-edition/servers/Idler.py b/sql-edition/servers/Idler.py
index e56f8d7..d11fe90 100755
--- a/sql-edition/servers/Idler.py
+++ b/sql-edition/servers/Idler.py
@@ -93,28 +93,37 @@ class TrainIdler(Idler):
 class OrderMaker:
 	def __init__(self, n=8):
 		self.n = n
-		self.a = []
-		self.u = []
-		self.s = []
-		for x in range(0,n):
-			self.u.append(False)
-		self.go()
-
-	def go(self):
-		from copy import deepcopy
-		if len(self.s) == self.n:
-			self.a.append(deepcopy(self.s))
-		else:
-			for x in range(0,self.n):
-				if self.u[x]: continue
-				self.s.append(x)
-				self.u[x] = True
-				self.go()
-				self.u[x] = False
-				self.s.pop()
-
-	def order(self):
-		return self.a
+		self.make_factorials(n)
+	
+	def make_factorials(self, n):
+		self.factorial = []
+		a = 1
+		for i in range(1,n+1):
+			self.factorial.append(a)
+			a *= i
+
+	def order(self, index):
+		used = []
+		for i in range(0,self.n):
+			used.append(i)
+		i = self.n-1
+		j = 0
+		res = []
+		while i >= 0:
+			a = index/self.factorial[i]
+			index %= self.factorial[i]
+			res.append(a+1)
+			i -= 1
+			j += 1
+		for i in range(0,self.n):
+			tmp = used[res[i]-1]
+			for j in range(res[i],self.n):
+				used[j-1] = used[j]
+			res[i] = tmp
+		return res
+
+	def __getitem__(self, i):
+		return self.order(i)
 
 class GrayIdler(Idler):
 	def __init__(self, v, one=None, zero=None, reorder=0):
@@ -128,7 +137,7 @@ class GrayIdler(Idler):
 		self.reorder = reorder
 		global orderings
 		if not orderings:
-			orderings = OrderMaker().order()
+			orderings = OrderMaker()
 
 	def next(self):
 		output = self.do_next_state()
-- 
2.20.1