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-rw-r--r--vendor/github.com/dustin/go-humanize/si.go123
1 files changed, 123 insertions, 0 deletions
diff --git a/vendor/github.com/dustin/go-humanize/si.go b/vendor/github.com/dustin/go-humanize/si.go
new file mode 100644
index 00000000..ae659e0e
--- /dev/null
+++ b/vendor/github.com/dustin/go-humanize/si.go
@@ -0,0 +1,123 @@
+package humanize
+
+import (
+ "errors"
+ "math"
+ "regexp"
+ "strconv"
+)
+
+var siPrefixTable = map[float64]string{
+ -24: "y", // yocto
+ -21: "z", // zepto
+ -18: "a", // atto
+ -15: "f", // femto
+ -12: "p", // pico
+ -9: "n", // nano
+ -6: "µ", // micro
+ -3: "m", // milli
+ 0: "",
+ 3: "k", // kilo
+ 6: "M", // mega
+ 9: "G", // giga
+ 12: "T", // tera
+ 15: "P", // peta
+ 18: "E", // exa
+ 21: "Z", // zetta
+ 24: "Y", // yotta
+}
+
+var revSIPrefixTable = revfmap(siPrefixTable)
+
+// revfmap reverses the map and precomputes the power multiplier
+func revfmap(in map[float64]string) map[string]float64 {
+ rv := map[string]float64{}
+ for k, v := range in {
+ rv[v] = math.Pow(10, k)
+ }
+ return rv
+}
+
+var riParseRegex *regexp.Regexp
+
+func init() {
+ ri := `^([\-0-9.]+)\s?([`
+ for _, v := range siPrefixTable {
+ ri += v
+ }
+ ri += `]?)(.*)`
+
+ riParseRegex = regexp.MustCompile(ri)
+}
+
+// ComputeSI finds the most appropriate SI prefix for the given number
+// and returns the prefix along with the value adjusted to be within
+// that prefix.
+//
+// See also: SI, ParseSI.
+//
+// e.g. ComputeSI(2.2345e-12) -> (2.2345, "p")
+func ComputeSI(input float64) (float64, string) {
+ if input == 0 {
+ return 0, ""
+ }
+ mag := math.Abs(input)
+ exponent := math.Floor(logn(mag, 10))
+ exponent = math.Floor(exponent/3) * 3
+
+ value := mag / math.Pow(10, exponent)
+
+ // Handle special case where value is exactly 1000.0
+ // Should return 1 M instead of 1000 k
+ if value == 1000.0 {
+ exponent += 3
+ value = mag / math.Pow(10, exponent)
+ }
+
+ value = math.Copysign(value, input)
+
+ prefix := siPrefixTable[exponent]
+ return value, prefix
+}
+
+// SI returns a string with default formatting.
+//
+// SI uses Ftoa to format float value, removing trailing zeros.
+//
+// See also: ComputeSI, ParseSI.
+//
+// e.g. SI(1000000, "B") -> 1 MB
+// e.g. SI(2.2345e-12, "F") -> 2.2345 pF
+func SI(input float64, unit string) string {
+ value, prefix := ComputeSI(input)
+ return Ftoa(value) + " " + prefix + unit
+}
+
+// SIWithDigits works like SI but limits the resulting string to the
+// given number of decimal places.
+//
+// e.g. SIWithDigits(1000000, 0, "B") -> 1 MB
+// e.g. SIWithDigits(2.2345e-12, 2, "F") -> 2.23 pF
+func SIWithDigits(input float64, decimals int, unit string) string {
+ value, prefix := ComputeSI(input)
+ return FtoaWithDigits(value, decimals) + " " + prefix + unit
+}
+
+var errInvalid = errors.New("invalid input")
+
+// ParseSI parses an SI string back into the number and unit.
+//
+// See also: SI, ComputeSI.
+//
+// e.g. ParseSI("2.2345 pF") -> (2.2345e-12, "F", nil)
+func ParseSI(input string) (float64, string, error) {
+ found := riParseRegex.FindStringSubmatch(input)
+ if len(found) != 4 {
+ return 0, "", errInvalid
+ }
+ mag := revSIPrefixTable[found[2]]
+ unit := found[3]
+
+ base, err := strconv.ParseFloat(found[1], 64)
+ return base * mag, unit, err
+}