51 lines
1.8 KiB
Go
51 lines
1.8 KiB
Go
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package units
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// SI units.
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type SI int64
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// SI unit multiples.
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const (
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Kilo SI = 1000
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Mega = Kilo * 1000
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Giga = Mega * 1000
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Tera = Giga * 1000
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Peta = Tera * 1000
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Exa = Peta * 1000
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)
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func MakeUnitMap(suffix, shortSuffix string, scale int64) map[string]float64 {
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res := map[string]float64{
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shortSuffix: 1,
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// see below for "k" / "K"
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"M" + suffix: float64(scale * scale),
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"G" + suffix: float64(scale * scale * scale),
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"T" + suffix: float64(scale * scale * scale * scale),
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"P" + suffix: float64(scale * scale * scale * scale * scale),
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"E" + suffix: float64(scale * scale * scale * scale * scale * scale),
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}
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// Standard SI prefixes use lowercase "k" for kilo = 1000.
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// For compatibility, and to be fool-proof, we accept both "k" and "K" in metric mode.
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//
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// However, official binary prefixes are always capitalized - "KiB" -
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// and we specifically never parse "kB" as 1024B because:
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//
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// (1) people pedantic enough to use lowercase according to SI unlikely to abuse "k" to mean 1024 :-)
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//
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// (2) Use of capital K for 1024 was an informal tradition predating IEC prefixes:
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// "The binary meaning of the kilobyte for 1024 bytes typically uses the symbol KB, with an
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// uppercase letter K."
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// -- https://en.wikipedia.org/wiki/Kilobyte#Base_2_(1024_bytes)
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// "Capitalization of the letter K became the de facto standard for binary notation, although this
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// could not be extended to higher powers, and use of the lowercase k did persist.[13][14][15]"
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// -- https://en.wikipedia.org/wiki/Binary_prefix#History
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// See also the extensive https://en.wikipedia.org/wiki/Timeline_of_binary_prefixes.
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if scale == 1024 {
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res["K"+suffix] = float64(scale)
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} else {
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res["k"+suffix] = float64(scale)
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res["K"+suffix] = float64(scale)
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}
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return res
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}
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