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|
package iso8601
// ValidFlags is a bitset type used to configure the behavior of the Valid
// function.
type ValidFlags int
const (
// Strict is a validation flag used to represent a string iso8601 validation
// (this is the default).
Strict ValidFlags = 0
// AllowSpaceSeparator allows the presence of a space instead of a 'T' as
// separator between the date and time.
AllowSpaceSeparator ValidFlags = 1 << iota
// AllowMissingTime allows the value to contain only a date.
AllowMissingTime
// AllowMissingSubsecond allows the value to contain only a date and time.
AllowMissingSubsecond
// AllowMissingTimezone allows the value to be missing the timezone
// information.
AllowMissingTimezone
// AllowNumericTimezone allows the value to represent timezones in their
// numeric form.
AllowNumericTimezone
// Flexible is a combination of all validation flag that allow for
// non-strict checking of the input value.
Flexible = AllowSpaceSeparator | AllowMissingTime | AllowMissingSubsecond | AllowMissingTimezone | AllowNumericTimezone
)
// Valid check value to verify whether or not it is a valid iso8601 time
// representation.
func Valid(value string, flags ValidFlags) bool {
var ok bool
// year
if value, ok = readDigits(value, 4, 4); !ok {
return false
}
if value, ok = readByte(value, '-'); !ok {
return false
}
// month
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
if value, ok = readByte(value, '-'); !ok {
return false
}
// day
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
if len(value) == 0 && (flags&AllowMissingTime) != 0 {
return true // date only
}
// separator
if value, ok = readByte(value, 'T'); !ok {
if (flags & AllowSpaceSeparator) == 0 {
return false
}
if value, ok = readByte(value, ' '); !ok {
return false
}
}
// hour
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
if value, ok = readByte(value, ':'); !ok {
return false
}
// minute
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
if value, ok = readByte(value, ':'); !ok {
return false
}
// second
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
// microsecond
if value, ok = readByte(value, '.'); !ok {
if (flags & AllowMissingSubsecond) == 0 {
return false
}
} else {
if value, ok = readDigits(value, 1, 9); !ok {
return false
}
}
if len(value) == 0 && (flags&AllowMissingTimezone) != 0 {
return true // date and time
}
// timezone
if value, ok = readByte(value, 'Z'); ok {
return len(value) == 0
}
if (flags & AllowSpaceSeparator) != 0 {
value, _ = readByte(value, ' ')
}
if value, ok = readByte(value, '+'); !ok {
if value, ok = readByte(value, '-'); !ok {
return false
}
}
// timezone hour
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
if value, ok = readByte(value, ':'); !ok {
if (flags & AllowNumericTimezone) == 0 {
return false
}
}
// timezone minute
if value, ok = readDigits(value, 2, 2); !ok {
return false
}
return len(value) == 0
}
func readDigits(value string, min, max int) (string, bool) {
if len(value) < min {
return value, false
}
i := 0
for i < max && i < len(value) && isDigit(value[i]) {
i++
}
if i < max && i < min {
return value, false
}
return value[i:], true
}
func readByte(value string, c byte) (string, bool) {
if len(value) == 0 {
return value, false
}
if value[0] != c {
return value, false
}
return value[1:], true
}
func isDigit(c byte) bool {
return '0' <= c && c <= '9'
}
|
