gotosocial/vendor/github.com/dsoprea/go-exif/v2/utility.go

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package exif
import (
"fmt"
"math"
"reflect"
"strconv"
"strings"
"time"
"github.com/dsoprea/go-logging"
"github.com/dsoprea/go-exif/v2/common"
"github.com/dsoprea/go-exif/v2/undefined"
)
var (
utilityLogger = log.NewLogger("exif.utility")
)
var (
timeType = reflect.TypeOf(time.Time{})
)
// ParseExifFullTimestamp parses dates like "2018:11:30 13:01:49" into a UTC
// `time.Time` struct.
func ParseExifFullTimestamp(fullTimestampPhrase string) (timestamp time.Time, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
parts := strings.Split(fullTimestampPhrase, " ")
datestampValue, timestampValue := parts[0], parts[1]
// Normalize the separators.
datestampValue = strings.ReplaceAll(datestampValue, "-", ":")
timestampValue = strings.ReplaceAll(timestampValue, "-", ":")
dateParts := strings.Split(datestampValue, ":")
year, err := strconv.ParseUint(dateParts[0], 10, 16)
if err != nil {
log.Panicf("could not parse year")
}
month, err := strconv.ParseUint(dateParts[1], 10, 8)
if err != nil {
log.Panicf("could not parse month")
}
day, err := strconv.ParseUint(dateParts[2], 10, 8)
if err != nil {
log.Panicf("could not parse day")
}
timeParts := strings.Split(timestampValue, ":")
hour, err := strconv.ParseUint(timeParts[0], 10, 8)
if err != nil {
log.Panicf("could not parse hour")
}
minute, err := strconv.ParseUint(timeParts[1], 10, 8)
if err != nil {
log.Panicf("could not parse minute")
}
second, err := strconv.ParseUint(timeParts[2], 10, 8)
if err != nil {
log.Panicf("could not parse second")
}
timestamp = time.Date(int(year), time.Month(month), int(day), int(hour), int(minute), int(second), 0, time.UTC)
return timestamp, nil
}
// ExifFullTimestampString produces a string like "2018:11:30 13:01:49" from a
// `time.Time` struct. It will attempt to convert to UTC first.
func ExifFullTimestampString(t time.Time) (fullTimestampPhrase string) {
return exifcommon.ExifFullTimestampString(t)
}
// ExifTag is one simple representation of a tag in a flat list of all of them.
type ExifTag struct {
// IfdPath is the fully-qualified IFD path (even though it is not named as
// such).
IfdPath string `json:"ifd_path"`
// TagId is the tag-ID.
TagId uint16 `json:"id"`
// TagName is the tag-name. This is never empty.
TagName string `json:"name"`
// UnitCount is the recorded number of units constution of the value.
UnitCount uint32 `json:"unit_count"`
// TagTypeId is the type-ID.
TagTypeId exifcommon.TagTypePrimitive `json:"type_id"`
// TagTypeName is the type name.
TagTypeName string `json:"type_name"`
// Value is the decoded value.
Value interface{} `json:"value"`
// ValueBytes is the raw, encoded value.
ValueBytes []byte `json:"value_bytes"`
// Formatted is the human representation of the first value (tag values are
// always an array).
FormattedFirst string `json:"formatted_first"`
// Formatted is the human representation of the complete value.
Formatted string `json:"formatted"`
// ChildIfdPath is the name of the child IFD this tag represents (if it
// represents any). Otherwise, this is empty.
ChildIfdPath string `json:"child_ifd_path"`
}
// String returns a string representation.
func (et ExifTag) String() string {
return fmt.Sprintf(
"ExifTag<"+
"IFD-PATH=[%s] "+
"TAG-ID=(0x%02x) "+
"TAG-NAME=[%s] "+
"TAG-TYPE=[%s] "+
"VALUE=[%v] "+
"VALUE-BYTES=(%d) "+
"CHILD-IFD-PATH=[%s]",
et.IfdPath, et.TagId, et.TagName, et.TagTypeName, et.FormattedFirst,
len(et.ValueBytes), et.ChildIfdPath)
}
// GetFlatExifData returns a simple, flat representation of all tags.
func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
eh, err := ParseExifHeader(exifData)
log.PanicIf(err)
im := NewIfdMappingWithStandard()
ti := NewTagIndex()
ie := NewIfdEnumerate(im, ti, exifData, eh.ByteOrder)
exifTags = make([]ExifTag, 0)
visitor := func(fqIfdPath string, ifdIndex int, ite *IfdTagEntry) (err error) {
// This encodes down to base64. Since this an example tool and we do not
// expect to ever decode the output, we are not worried about
// specifically base64-encoding it in order to have a measure of
// control.
valueBytes, err := ite.GetRawBytes()
if err != nil {
if err == exifundefined.ErrUnparseableValue {
return nil
}
log.Panic(err)
}
value, err := ite.Value()
if err != nil {
if err == exifcommon.ErrUnhandledUndefinedTypedTag {
value = exifundefined.UnparseableUnknownTagValuePlaceholder
} else {
log.Panic(err)
}
}
et := ExifTag{
IfdPath: fqIfdPath,
TagId: ite.TagId(),
TagName: ite.TagName(),
UnitCount: ite.UnitCount(),
TagTypeId: ite.TagType(),
TagTypeName: ite.TagType().String(),
Value: value,
ValueBytes: valueBytes,
ChildIfdPath: ite.ChildIfdPath(),
}
et.Formatted, err = ite.Format()
log.PanicIf(err)
et.FormattedFirst, err = ite.FormatFirst()
log.PanicIf(err)
exifTags = append(exifTags, et)
return nil
}
_, err = ie.Scan(exifcommon.IfdStandardIfdIdentity, eh.FirstIfdOffset, visitor)
log.PanicIf(err)
return exifTags, nil
}
// GpsDegreesEquals returns true if the two `GpsDegrees` are identical.
func GpsDegreesEquals(gi1, gi2 GpsDegrees) bool {
if gi2.Orientation != gi1.Orientation {
return false
}
degreesRightBound := math.Nextafter(gi1.Degrees, gi1.Degrees+1)
minutesRightBound := math.Nextafter(gi1.Minutes, gi1.Minutes+1)
secondsRightBound := math.Nextafter(gi1.Seconds, gi1.Seconds+1)
if gi2.Degrees < gi1.Degrees || gi2.Degrees >= degreesRightBound {
return false
} else if gi2.Minutes < gi1.Minutes || gi2.Minutes >= minutesRightBound {
return false
} else if gi2.Seconds < gi1.Seconds || gi2.Seconds >= secondsRightBound {
return false
}
return true
}
// IsTime returns true if the value is a `time.Time`.
func IsTime(v interface{}) bool {
return reflect.TypeOf(v) == timeType
}