Grand test fixup (#138)

* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig

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

@@ -0,0 +1,233 @@
+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
+}