57 lines
1,014 B
Go
57 lines
1,014 B
Go
package main
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import (
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"fmt"
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"html/template"
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"strconv"
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)
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type ScientificNotationValue float64
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func (s *ScientificNotationValue) UnmarshalText(text []byte) error {
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f, err := strconv.ParseFloat(string(text), 64)
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if err != nil {
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return err
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}
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*s = ScientificNotationValue(f)
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return nil
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}
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// formatMbarHTML formats a millibar value using scientific notation and returns
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// a HTML fragment (for superscript support).
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func formatMbarHTML(v float32) template.HTML {
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exp := 0
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for v < 1 {
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v *= 10
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exp -= 1
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}
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for v >= 10 {
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v /= 10
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exp += 1
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}
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res := fmt.Sprintf("%.3f", v)
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res += fmt.Sprintf(" x 10<sup>%d</sup>", exp)
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res += " mbar"
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return template.HTML(res)
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}
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func formatMbar(v float32) string {
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exp := 0
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for v < 1 {
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v *= 10
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exp -= 1
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}
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for v >= 10 {
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v /= 10
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exp += 1
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}
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res := fmt.Sprintf("%.3f", v)
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res += fmt.Sprintf("e%d", exp)
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return res
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}
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func (s *ScientificNotationValue) MarshalText() ([]byte, error) {
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v := float32(*s)
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res := formatMbar(v)
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return []byte(res), nil
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}
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