goext/timeext/parser.go

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2022-12-07 23:15:16 +01:00
package timeext
import (
"errors"
"fmt"
"strconv"
"strings"
"time"
)
var durationShortStringMap = map[string]time.Duration{
"ns": time.Nanosecond,
"nanosecond": time.Nanosecond,
"nanoseconds": time.Nanosecond,
"us": time.Microsecond,
"microsecond": time.Microsecond,
"microseconds": time.Microsecond,
"ms": time.Millisecond,
"millisecond": time.Millisecond,
"milliseconds": time.Millisecond,
"s": time.Second,
"sec": time.Second,
"second": time.Second,
"seconds": time.Second,
"m": time.Minute,
"min": time.Minute,
"minute": time.Minute,
"minutes": time.Minute,
"h": time.Hour,
"hour": time.Hour,
"hours": time.Hour,
"d": 24 * time.Hour,
"day": 24 * time.Hour,
"days": 24 * time.Hour,
"w": 7 * 24 * time.Hour,
"wk": 7 * 24 * time.Hour,
"week": 7 * 24 * time.Hour,
"weeks": 7 * 24 * time.Hour,
}
// ParseDurationShortString parses a duration in string format to a time.Duration
// Examples for allowed formats:
// - '10m'
// - '10min'
// - '1minute'
// - '10minutes'
// - '10.5minutes'
// - '50s'
// - '50sec'
// - '1second'
// - '50seconds'
// - '100ms'
// - '100millisseconds'
// - '1h'
// - '1hour'
// - '2hours'
// - '1d'
// - '1day'
// - '10days'
// - '1d10m'
// - '1d10m200sec'
// - '1d:10m'
// - '1d 10m'
// - '1d,10m'
func ParseDurationShortString(s string) (time.Duration, error) {
s = strings.ToLower(s)
segments := make([]string, 0)
collector := ""
prevWasNum := true
for _, chr := range s {
if chr >= '0' && chr <= '9' || chr == '.' {
if prevWasNum {
collector += string(chr)
} else {
segments = append(segments, collector)
prevWasNum = true
collector = string(chr)
}
} else if chr == ' ' || chr == ':' || chr == ',' {
continue
} else if chr >= 'a' && chr <= 'z' {
prevWasNum = false
collector += string(chr)
} else {
return 0, errors.New("unexpected character: " + string(chr))
}
}
if !prevWasNum {
segments = append(segments, collector)
}
result := time.Duration(0)
for _, seg := range segments {
segDur, err := parseDurationShortStringSegment(seg)
if err != nil {
return 0, err
}
result += segDur
}
return result, nil
}
func parseDurationShortStringSegment(segment string) (time.Duration, error) {
num := ""
unit := ""
part0 := true
for _, chr := range segment {
if part0 {
if chr >= 'a' && chr <= 'z' {
part0 = false
unit += string(chr)
} else if chr >= '0' && chr <= '9' || chr == '.' {
num += string(chr)
} else {
return 0, errors.New(fmt.Sprintf("Unexpected character '%s' in segment [%s]", string(chr), segment))
}
} else {
if chr >= 'a' && chr <= 'z' {
unit += string(chr)
} else if chr >= '0' && chr <= '9' || chr == '.' {
return 0, errors.New(fmt.Sprintf("Unexpected number '%s' in segment [%s]", string(chr), segment))
} else {
return 0, errors.New(fmt.Sprintf("Unexpected character '%s' in segment [%s]", string(chr), segment))
}
}
}
fpnum, err := strconv.ParseFloat(num, 64)
if err != nil {
return 0, errors.New(fmt.Sprintf("Failed to parse floating-point number '%s' in segment [%s]", num, segment))
}
if mult, ok := durationShortStringMap[unit]; ok {
return time.Duration(int64(fpnum * float64(mult))), nil
} else {
return 0, errors.New(fmt.Sprintf("Unknown unit '%s' in segment [%s]", unit, segment))
}
}