diff --git a/option/time_unit.go b/option/time_unit.go new file mode 100644 index 00000000..5e531dad --- /dev/null +++ b/option/time_unit.go @@ -0,0 +1,226 @@ +package option + +import ( + "errors" + "time" +) + +// Copyright 2010 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +const durationDay = 24 * time.Hour + +var unitMap = map[string]uint64{ + "ns": uint64(time.Nanosecond), + "us": uint64(time.Microsecond), + "µs": uint64(time.Microsecond), // U+00B5 = micro symbol + "μs": uint64(time.Microsecond), // U+03BC = Greek letter mu + "ms": uint64(time.Millisecond), + "s": uint64(time.Second), + "m": uint64(time.Minute), + "h": uint64(time.Hour), + "d": uint64(durationDay), +} + +// ParseDuration parses a duration string. +// A duration string is a possibly signed sequence of +// decimal numbers, each with optional fraction and a unit suffix, +// such as "300ms", "-1.5h" or "2h45m". +// Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h". +func ParseDuration(s string) (Duration, error) { + // [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+ + orig := s + var d uint64 + neg := false + + // Consume [-+]? + if s != "" { + c := s[0] + if c == '-' || c == '+' { + neg = c == '-' + s = s[1:] + } + } + // Special case: if all that is left is "0", this is zero. + if s == "0" { + return 0, nil + } + if s == "" { + return 0, errors.New("time: invalid duration " + quote(orig)) + } + for s != "" { + var ( + v, f uint64 // integers before, after decimal point + scale float64 = 1 // value = v + f/scale + ) + + var err error + + // The next character must be [0-9.] + if !(s[0] == '.' || '0' <= s[0] && s[0] <= '9') { + return 0, errors.New("time: invalid duration " + quote(orig)) + } + // Consume [0-9]* + pl := len(s) + v, s, err = leadingInt(s) + if err != nil { + return 0, errors.New("time: invalid duration " + quote(orig)) + } + pre := pl != len(s) // whether we consumed anything before a period + + // Consume (\.[0-9]*)? + post := false + if s != "" && s[0] == '.' { + s = s[1:] + pl := len(s) + f, scale, s = leadingFraction(s) + post = pl != len(s) + } + if !pre && !post { + // no digits (e.g. ".s" or "-.s") + return 0, errors.New("time: invalid duration " + quote(orig)) + } + + // Consume unit. + i := 0 + for ; i < len(s); i++ { + c := s[i] + if c == '.' || '0' <= c && c <= '9' { + break + } + } + if i == 0 { + return 0, errors.New("time: missing unit in duration " + quote(orig)) + } + u := s[:i] + s = s[i:] + unit, ok := unitMap[u] + if !ok { + return 0, errors.New("time: unknown unit " + quote(u) + " in duration " + quote(orig)) + } + if v > 1<<63/unit { + // overflow + return 0, errors.New("time: invalid duration " + quote(orig)) + } + v *= unit + if f > 0 { + // float64 is needed to be nanosecond accurate for fractions of hours. + // v >= 0 && (f*unit/scale) <= 3.6e+12 (ns/h, h is the largest unit) + v += uint64(float64(f) * (float64(unit) / scale)) + if v > 1<<63 { + // overflow + return 0, errors.New("time: invalid duration " + quote(orig)) + } + } + d += v + if d > 1<<63 { + return 0, errors.New("time: invalid duration " + quote(orig)) + } + } + if neg { + return -Duration(d), nil + } + if d > 1<<63-1 { + return 0, errors.New("time: invalid duration " + quote(orig)) + } + return Duration(d), nil +} + +var errLeadingInt = errors.New("time: bad [0-9]*") // never printed + +// leadingInt consumes the leading [0-9]* from s. +func leadingInt[bytes []byte | string](s bytes) (x uint64, rem bytes, err error) { + i := 0 + for ; i < len(s); i++ { + c := s[i] + if c < '0' || c > '9' { + break + } + if x > 1<<63/10 { + // overflow + return 0, rem, errLeadingInt + } + x = x*10 + uint64(c) - '0' + if x > 1<<63 { + // overflow + return 0, rem, errLeadingInt + } + } + return x, s[i:], nil +} + +// leadingFraction consumes the leading [0-9]* from s. +// It is used only for fractions, so does not return an error on overflow, +// it just stops accumulating precision. +func leadingFraction(s string) (x uint64, scale float64, rem string) { + i := 0 + scale = 1 + overflow := false + for ; i < len(s); i++ { + c := s[i] + if c < '0' || c > '9' { + break + } + if overflow { + continue + } + if x > (1<<63-1)/10 { + // It's possible for overflow to give a positive number, so take care. + overflow = true + continue + } + y := x*10 + uint64(c) - '0' + if y > 1<<63 { + overflow = true + continue + } + x = y + scale *= 10 + } + return x, scale, s[i:] +} + +// These are borrowed from unicode/utf8 and strconv and replicate behavior in +// that package, since we can't take a dependency on either. +const ( + lowerhex = "0123456789abcdef" + runeSelf = 0x80 + runeError = '\uFFFD' +) + +func quote(s string) string { + buf := make([]byte, 1, len(s)+2) // slice will be at least len(s) + quotes + buf[0] = '"' + for i, c := range s { + if c >= runeSelf || c < ' ' { + // This means you are asking us to parse a time.Duration or + // time.Location with unprintable or non-ASCII characters in it. + // We don't expect to hit this case very often. We could try to + // reproduce strconv.Quote's behavior with full fidelity but + // given how rarely we expect to hit these edge cases, speed and + // conciseness are better. + var width int + if c == runeError { + width = 1 + if i+2 < len(s) && s[i:i+3] == string(runeError) { + width = 3 + } + } else { + width = len(string(c)) + } + for j := 0; j < width; j++ { + buf = append(buf, `\x`...) + buf = append(buf, lowerhex[s[i+j]>>4]) + buf = append(buf, lowerhex[s[i+j]&0xF]) + } + } else { + if c == '"' || c == '\\' { + buf = append(buf, '\\') + } + buf = append(buf, string(c)...) + } + } + buf = append(buf, '"') + return string(buf) +} diff --git a/option/types.go b/option/types.go index 520c3503..2f029098 100644 --- a/option/types.go +++ b/option/types.go @@ -164,7 +164,7 @@ func (d *Duration) UnmarshalJSON(bytes []byte) error { if err != nil { return err } - duration, err := time.ParseDuration(value) + duration, err := ParseDuration(value) if err != nil { return err }