prosody
994c4a333199
util/human/units.lua

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util/human/units.lua @ 10886:994c4a333199

util.human.units: A library for formatting numbers with SI units
author Kim Alvefur <zash@zash.se>
date Fri, 04 Jan 2019 08:46:26 +0100
child 10888:42a0d9089de9
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
10886
994c4a333199 util.human.units: A library for formatting numbers with SI units
Kim Alvefur <zash@zash.se>
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1 local large = {
994c4a333199 util.human.units: A library for formatting numbers with SI units
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2 "k", 1000,
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3 "M", 1000000,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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4 "G", 1000000000,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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5 "T", 1000000000000,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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6 "P", 1000000000000000,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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7 "E", 1000000000000000000,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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8 "Z", 1000000000000000000000,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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9 "Y", 1000000000000000000000000,
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10 }
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11 local small = {
994c4a333199 util.human.units: A library for formatting numbers with SI units
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12 "m", 0.001,
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13 "μ", 0.000001,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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14 "n", 0.000000001,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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15 "p", 0.000000000001,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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16 "f", 0.000000000000001,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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17 "a", 0.000000000000000001,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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18 "z", 0.000000000000000000001,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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19 "y", 0.000000000000000000000001,
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20 }
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21
994c4a333199 util.human.units: A library for formatting numbers with SI units
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22 local binary = {
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23 "Ki", 2^10,
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24 "Mi", 2^20,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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25 "Gi", 2^30,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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26 "Ti", 2^40,
994c4a333199 util.human.units: A library for formatting numbers with SI units
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27 "Pi", 2^50,
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28 "Ei", 2^60,
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29 "Zi", 2^70,
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30 "Yi", 2^80,
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31 }
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32
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33 -- n: number, the number to format
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34 -- unit: string, the base unit
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35 -- b: optional enum 'b', thousands base
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36 local function format(n, unit, b) --> string
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37 local round = math.floor;
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38 local prefixes = large;
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39 local logbase = 1000;
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40 local fmt = "%.3g %s%s";
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41 if n == 0 then
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42 return fmt:format(n, "", unit);
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43 end
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44 if b == 'b' then
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45 prefixes = binary;
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46 logbase = 1024;
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47 elseif n < 1 then
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48 prefixes = small;
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49 round = math.ceil;
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50 end
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51 local m = math.max(0, math.min(8, round(math.abs(math.log(math.abs(n), logbase)))));
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52 local prefix, multiplier = table.unpack(prefixes, m * 2-1, m*2);
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53 return fmt:format(n / (multiplier or 1), prefix or "", unit);
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54 end
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55
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56 return {
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57 format = format;
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58 };