105 lines
2.8 KiB
Lua
105 lines
2.8 KiB
Lua
--
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-- data.lua: property and methods for manipulating incoming measurements
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-- Copyright (c) 2009 jokamajo.org
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-- 2010 flukso.net
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--
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-- This program is free software; you can redistribute it and/or
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-- modify it under the terms of the GNU General Public License
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-- as published by the Free Software Foundation; either version 2
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-- of the License, or (at your option) any later version.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program; if not, write to the Free Software
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-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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--
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-- $Id$
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--
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local os, math, table, string =
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os, math, table, string
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local getfenv, setmetatable, pairs, ipairs =
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getfenv, setmetatable, pairs, ipairs
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module (...)
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local modenv = getfenv() -- module environment
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-- private
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local function timestamps(T)
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local H = {} -- helper table, an indexed array containing all the measurement's timestamps
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for timestamp in pairs(T) do H[#H+1] = timestamp end
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table.sort(H) -- sort in ascending order, oldest timestamps will be treated first
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return H
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end
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function new()
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return setmetatable({}, {__index = modenv})
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end
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function add(M, meter, timestamp, value)
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if not M[meter] then M[meter] = {} end
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M[meter][timestamp] = value
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end
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function clear(M)
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for meter in pairs(M) do
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M[meter] = nil
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end
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end
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function filter(M, span, offset)
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for meter, T in pairs(M) do
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local H = timestamps(T)
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local i = 2
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while not (H[i+1] == nil or H[i] > os.time()-offset) do
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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
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T[H[i]] = nil
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table.remove(H, i)
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else
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i = i+1
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end
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end
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end
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end
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function truncate(M, cutoff)
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for meter, T in pairs(M) do
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local H = timestamps(T)
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for i = H[1], os.time() - cutoff do
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T[i] = nil
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end
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end
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end
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function fill(M)
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for meter, T in pairs(M) do
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local H = timestamps(T)
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for i = H[#H]-1, H[1]+1, -1 do
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if T[i] == nil or T[i] == '"nan"' then T[i] = T[i+1] end
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end
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for i = H[#H]+1, os.time() do
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T[i] = '"nan"'
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end
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end
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end
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function json_encode(M)
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local J = {}
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for meter, T in pairs(M) do
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local H = timestamps(T)
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local SB = {'['} -- use a string buffer for building up the JSON string
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for k, timestamp in ipairs(H) do
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SB[#SB+1] = '[' .. timestamp .. ',' .. T[timestamp] .. '],'
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end
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SB[#SB] = SB[#SB]:sub(1, -2) -- remove the trialing comma from the last entry
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SB[#SB+1] = ']'
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J[meter] = table.concat(SB)
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end
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return J
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end
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