flm01/openwrt/package/flukso/src/data.lua

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--
-- data.lua: property and methods for manipulating incoming measurements
-- Copyright (c) 2009 jokamajo.org
--
-- This program is free software; you can redistribute it and/or
-- modify it under the terms of the GNU General Public License
-- as published by the Free Software Foundation; either version 2
-- of the License, or (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
--
-- $Id$
--
local os, math, table =
os, math, table
local getfenv, setmetatable, pairs =
getfenv, setmetatable, pairs
module (...)
local modenv = getfenv() -- module environment
function new()
return setmetatable({}, {__index = modenv})
end
function add(M, meter, timestamp, value)
if not M[meter] then M[meter] = {} end
M[meter][timestamp] = value
end
function clear(M)
for meter in pairs(M) do
M[meter] = nil
end
end
function filter(M, span, offset)
for meter, T in pairs(M) do
local H = {} -- helper table, an indexed array containing all the measurement's timestamps
for timestamp in pairs(T) do H[#H+1] = timestamp end
table.sort(H) -- sort in ascending order, oldest timestamps will be treated first
local i = 2
while not (H[i+1] == nil or H[i] > os.time()-offset) do
if math.floor(H[i-1]/span) == math.floor(H[i]/span) and math.floor(H[i]/span) == math.floor(H[i+1]/span) then
T[H[i]] = nil
table.remove(H, i)
else
i = i+1
end
end
end
end