From dcf713d9942496a8109d1ec31f2b36e469d5c129 Mon Sep 17 00:00:00 2001
From: Bart Trojanowski <bart@jukie.net>
Date: Tue, 4 Dec 2007 19:57:02 -0500
Subject: [PATCH] history class

---
 core/history.lua | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 core/history.lua

diff --git a/core/history.lua b/core/history.lua
new file mode 100644
index 0000000..e4d404d
--- /dev/null
+++ b/core/history.lua
@@ -0,0 +1,81 @@
+
+local os = require("os")
+local io = require("io")
+local string = require("string")
+--       local posix = require("posix")
+--       local table = require("table")
+--       local math = require("math")
+--       local type = type
+--       local error = error
+local print = print
+--       local pcall = pcall
+--       local pairs = pairs
+--       local package = package
+--       local require = require
+local tostring = tostring
+--       local tonumber = tonumber
+local setmetatable = setmetatable
+
+module("history")
+
+
+history = {}
+function new (size)
+        local o = {}
+
+        setmetatable (o,history)
+        history.__index = history
+
+        o.data = {}
+        o.data[size] = nil
+        o.size = size
+        o.count = 0
+        o.last = 0
+
+        return o
+end
+
+function history:add (entry)
+        if self.count < self.size then
+                self.count = self.count + 1
+                self.last = self.count
+                self.data[self.last] = entry
+        else
+                self.last = 1 + (self.last % self.size)
+                self.data[self.last] = entry
+        end
+end
+
+function history:oldest ()
+        if self.count then
+                local i = 1 + ((self.last + self.size - self.count) % self.size)
+                return self.data[i]
+        end
+        return nil
+end
+
+function history:newest ()
+        if self.count then
+                return self.data[self.last]
+        end
+        return nil
+end
+
+function history:walk_reverse ()
+        local s = self
+        local count = s.count
+        local index = s.last
+
+        return function ()
+                local ret = nil
+                if count > 0 then
+                        local i = 1 + (s.size + index - 1) % s.size
+                        ret = s.data[i]
+                        count = count - 1
+                        index = index - 1
+                end
+                return ret
+        end
+end
+
+
-- 
2.11.4.GIT