const (
// ExifAddressableAreaStart is the absolute offset in the file that all
// offsets are relative to.
ExifAddressableAreaStart = uint32(0x0)
// ExifDefaultFirstIfdOffset is essentially the number of bytes in addition
// to `ExifAddressableAreaStart` that you have to move in order to escape
// the rest of the header and get to the earliest point where we can put
// stuff (which has to be the first IFD). This is the size of the header
// sequence containing the two-character byte-order, two-character fixed-
// bytes, and the four bytes describing the first-IFD offset.
ExifDefaultFirstIfdOffset = uint32(2 + 2 + 4)
)
const (
// ThumbnailFqIfdPath is the fully-qualified IFD path that the thumbnail
// must be found in.
ThumbnailFqIfdPath = "IFD1"
// ThumbnailOffsetTagId returns the tag-ID of the thumbnail offset.
ThumbnailOffsetTagId = 0x0201
// ThumbnailSizeTagId returns the tag-ID of the thumbnail size.
ThumbnailSizeTagId = 0x0202
)
const (
// TagGpsVersionId is the ID of the GPS version tag.
TagGpsVersionId = 0x0000
// TagLatitudeId is the ID of the GPS latitude tag.
TagLatitudeId = 0x0002
// TagLatitudeRefId is the ID of the GPS latitude orientation tag.
TagLatitudeRefId = 0x0001
// TagLongitudeId is the ID of the GPS longitude tag.
TagLongitudeId = 0x0004
// TagLongitudeRefId is the ID of the GPS longitude-orientation tag.
TagLongitudeRefId = 0x0003
// TagTimestampId is the ID of the GPS time tag.
TagTimestampId = 0x0007
// TagDatestampId is the ID of the GPS date tag.
TagDatestampId = 0x001d
// TagAltitudeId is the ID of the GPS altitude tag.
TagAltitudeId = 0x0006
// TagAltitudeRefId is the ID of the GPS altitude-orientation tag.
TagAltitudeRefId = 0x0005
)
const (
// ExifSignatureLength is the number of bytes in the EXIF signature (which
// customarily includes the first IFD offset).
ExifSignatureLength = 8
)
const (
// Tag-ID + Tag-Type + Unit-Count + Value/Offset.
IfdTagEntrySize = uint32(2 + 2 + 4 + 4)
)
var (
// ErrTagNotFound indicates that the tag was not found.
ErrTagNotFound = errors.New("tag not found")
// ErrTagNotKnown indicates that the tag is not registered with us as a
// known tag.
ErrTagNotKnown = errors.New("tag is not known")
)
var (
ExifBigEndianSignature = [4]byte{'M', 'M', 0x00, 0x2a}
ExifLittleEndianSignature = [4]byte{'I', 'I', 0x2a, 0x00}
)
var (
ErrNoExif = errors.New("no exif data")
ErrExifHeaderError = errors.New("exif header error")
)
var (
ErrTagEntryNotFound = errors.New("tag entry not found")
ErrChildIbNotFound = errors.New("child IB not found")
)
var (
// ErrNoThumbnail means that no thumbnail was found.
ErrNoThumbnail = errors.New("no thumbnail")
// ErrNoGpsTags means that no GPS info was found.
ErrNoGpsTags = errors.New("no gps tags")
// ErrTagTypeNotValid means that the tag-type is not valid.
ErrTagTypeNotValid = errors.New("tag type invalid")
// ErrOffsetInvalid means that the file offset is not valid.
ErrOffsetInvalid = errors.New("file offset invalid")
)
var (
// ErrGpsCoordinatesNotValid means that some part of the geographic data was
// unparseable.
ErrGpsCoordinatesNotValid = errors.New("GPS coordinates not valid")
)
var (
// ValidGpsVersions is the list of recognized EXIF GPS versions/signatures.
ValidGpsVersions = [][4]byte{
{2, 0, 0, 0},
{2, 2, 0, 0},
{2, 3, 0, 0},
}
)
func BuildExifHeader(byteOrder binary.ByteOrder, firstIfdOffset uint32) (headerBytes []byte, err error)
BuildExifHeader constructs the bytes that go at the front of the stream.
▹ Example
func Collect(ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, exifData []byte) (eh ExifHeader, index IfdIndex, err error)
Collect recursively builds a static structure of all IFDs and tags.
func GetFlatExifData(exifData []byte, so *ScanOptions) (exifTags []ExifTag, med *MiscellaneousExifData, err error)
GetFlatExifData returns a simple, flat representation of all tags.
func GetFlatExifDataUniversalSearch(exifData []byte, so *ScanOptions, doUniversalSearch bool) (exifTags []ExifTag, med *MiscellaneousExifData, err error)
GetFlatExifDataUniversalSearch returns a simple, flat representation of all tags.
func GetFlatExifDataUniversalSearchWithReadSeeker(rs io.ReadSeeker, so *ScanOptions, doUniversalSearch bool) (exifTags []ExifTag, med *MiscellaneousExifData, err error)
GetFlatExifDataUniversalSearchWithReadSeeker returns a simple, flat representation of all tags given a ReadSeeker.
func GpsDegreesEquals(gi1, gi2 GpsDegrees) bool
GpsDegreesEquals returns true if the two `GpsDegrees` are identical.
func LoadStandardTags(ti *TagIndex) (err error)
LoadStandardTags registers the tags that all devices/applications should support.
func SearchAndExtractExif(data []byte) (rawExif []byte, err error)
SearchAndExtractExif searches for an EXIF blob in the byte-slice.
func SearchAndExtractExifN(data []byte, n int) (rawExif []byte, err error)
SearchAndExtractExifN searches for an EXIF blob in the byte-slice, but skips the given number of EXIF blocks first. This is a forensics tool that helps identify multiple EXIF blocks in a file.
func SearchAndExtractExifWithReader(r io.Reader) (rawExif []byte, err error)
SearchAndExtractExifWithReader searches for an EXIF blob using an `io.Reader`. We can't know how much long the EXIF data is without parsing it, so this will likely grab up a lot of the image-data, too.
func SearchFileAndExtractExif(filepath string) (rawExif []byte, err error)
SearchFileAndExtractExif returns a slice from the beginning of the EXIF data to the end of the file (it's not practical to try and calculate where the data actually ends).
type BuilderTag struct {
// contains filtered or unexported fields
}
func NewBuilderTag(ifdPath string, tagId uint16, typeId exifcommon.TagTypePrimitive, value *IfdBuilderTagValue, byteOrder binary.ByteOrder) *BuilderTag
func NewChildIfdBuilderTag(ifdPath string, tagId uint16, value *IfdBuilderTagValue) *BuilderTag
func NewStandardBuilderTag(ifdPath string, it *IndexedTag, byteOrder binary.ByteOrder, value interface{}) *BuilderTag
NewStandardBuilderTag constructs a `BuilderTag` instance. The type is looked up. `ii` is the type of IFD that owns this tag.
func (bt *BuilderTag) SetValue(byteOrder binary.ByteOrder, value interface{}) (err error)
▹ Example
func (bt *BuilderTag) String() string
func (bt *BuilderTag) Value() (value *IfdBuilderTagValue)
type ByteWriter struct {
// contains filtered or unexported fields
}
func NewByteWriter(b *bytes.Buffer, byteOrder binary.ByteOrder) (bw *ByteWriter)
func (bw ByteWriter) WriteFourBytes(value []byte) (err error)
func (bw ByteWriter) WriteUint16(value uint16) (err error)
func (bw ByteWriter) WriteUint32(value uint32) (err error)
type ExifBlobSeeker interface {
GetReadSeeker(initialOffset int64) (rs io.ReadSeeker, err error)
}
type ExifHeader struct {
ByteOrder binary.ByteOrder
FirstIfdOffset uint32
}
func ParseExifHeader(data []byte) (eh ExifHeader, err error)
ParseExifHeader parses the bytes at the very top of the header.
This will panic with ErrNoExif on any data errors so that we can double as an EXIF-detection routine.
func Visit(rootIfdIdentity *exifcommon.IfdIdentity, ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, exifData []byte, visitor TagVisitorFn, so *ScanOptions) (eh ExifHeader, furthestOffset uint32, err error)
Visit recursively invokes a callback for every tag.
func (eh ExifHeader) String() string
ExifReadSeeker knows how to retrieve data from the EXIF blob relative to the beginning of the blob (so, absolute position (0) is the first byte of the EXIF data).
type ExifReadSeeker struct {
// contains filtered or unexported fields
}
func NewExifReadSeeker(rs io.ReadSeeker) *ExifReadSeeker
func NewExifReadSeekerWithBytes(exifData []byte) *ExifReadSeeker
func (edbs *ExifReadSeeker) GetReadSeeker(initialOffset int64) (rs io.ReadSeeker, err error)
Fork creates a new ReadSeeker instead that wraps a BouncebackReader to maintain its own position in the stream.
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"`
}
func (et ExifTag) String() string
String returns a string representation.
GpsDegrees is a high-level struct representing geographic data.
type GpsDegrees struct {
// Orientation describes the N/E/S/W direction that this position is
// relative to.
Orientation byte
// Degrees is a simple float representing the underlying rational degrees
// amount.
Degrees float64
// Minutes is a simple float representing the underlying rational minutes
// amount.
Minutes float64
// Seconds is a simple float representing the underlying ration seconds
// amount.
Seconds float64
}
func NewGpsDegreesFromRationals(refValue string, rawCoordinate []exifcommon.Rational) (gd GpsDegrees, err error)
NewGpsDegreesFromRationals returns a GpsDegrees struct given the EXIF-encoded information. The refValue is the N/E/S/W direction that this position is relative to.
func (d GpsDegrees) Decimal() float64
Decimal calculates and returns the simplified float representation of the component degrees.
func (d GpsDegrees) Raw() []exifcommon.Rational
Raw returns a Rational struct that can be used to *write* coordinates. In practice, the denominator are typically (1) in the original EXIF data, and, that being the case, this will best preserve precision.
func (d GpsDegrees) String() string
String provides returns a descriptive string.
GpsInfo encapsulates all of the geographic information in one place.
type GpsInfo struct {
Latitude, Longitude GpsDegrees
Altitude int
Timestamp time.Time
}
func (gi *GpsInfo) S2CellId() s2.CellID
S2CellId returns the cell-ID of the geographic location on the earth.
func (gi *GpsInfo) String() string
String returns a descriptive string.
Ifd represents a single, parsed IFD.
type Ifd struct {
// contains filtered or unexported fields
}
func FindIfdFromRootIfd(rootIfd *Ifd, ifdPath string) (ifd *Ifd, err error)
FindIfdFromRootIfd returns the given `Ifd` given the root-IFD and path of the desired IFD.
func (ifd *Ifd) ByteOrder() binary.ByteOrder
Offset returns the offset of the IFD in the stream.
func (ifd *Ifd) ChildIfdIndex() map[string]*Ifd
ChildWithIfdPath returns a map of all child IFDs of this IFD.
func (ifd *Ifd) ChildWithIfdPath(iiChild *exifcommon.IfdIdentity) (childIfd *Ifd, err error)
ChildWithIfdPath returns an `Ifd` struct for the given child of the current IFD.
func (ifd *Ifd) Children() []*Ifd
Children returns a flat list of all child IFDs of this IFD.
func (ifd *Ifd) DumpTags() []*IfdTagEntry
DumpTags prints the IFD hierarchy.
func (ifd *Ifd) DumpTree() []string
DumpTree returns a list of strings describing the IFD hierarchy.
func (ifd *Ifd) Entries() []*IfdTagEntry
Entries returns a flat list of all tags for this IFD.
func (ifd *Ifd) EntriesByTagId() map[uint16][]*IfdTagEntry
EntriesByTagId returns a map of all tags for this IFD.
func (ifd *Ifd) EnumerateTagsRecursively(visitor ParsedTagVisitor) (err error)
EnumerateTagsRecursively calls the given visitor function for every tag and IFD in the current IFD, recursively.
▹ Example
func (ifd *Ifd) FindTagWithId(tagId uint16) (results []*IfdTagEntry, err error)
FindTagWithId returns a list of tags (usually just zero or one) that match the given tag ID. This is efficient.
func (ifd *Ifd) FindTagWithName(tagName string) (results []*IfdTagEntry, err error)
FindTagWithName returns a list of tags (usually just zero or one) that match the given tag name. This is not efficient (though the labor is trivial).
▹ Example
func (ifd *Ifd) GpsInfo() (gi *GpsInfo, err error)
GpsInfo parses and consolidates the GPS info. This can only be called on the GPS IFD.
▹ Example
func (ifd *Ifd) IfdIdentity() *exifcommon.IfdIdentity
IfdIdentity returns IFD identity that this struct represents.
func (ifd *Ifd) NextIfd() *Ifd
NextIfd returns the Ifd struct for the next IFD in the chain.
func (ifd *Ifd) Offset() uint32
Offset returns the offset of the IFD in the stream.
func (ifd *Ifd) ParentTagIndex() int
ParentTagIndex returns the position of this IFD's tag in its parent IFD (*if* there is a parent).
func (ifd *Ifd) PrintIfdTree()
PrintIfdTree prints the IFD hierarchy.
func (ifd *Ifd) PrintTagTree(populateValues bool)
PrintTagTree prints the IFD hierarchy.
func (ifd *Ifd) String() string
String returns a description string.
func (ifd *Ifd) Thumbnail() (data []byte, err error)
Thumbnail returns the raw thumbnail bytes. This is typically directly readable by any standard image viewer.
▹ Example
type IfdBuilder struct {
// contains filtered or unexported fields
}
func GetOrCreateIbFromRootIb(rootIb *IfdBuilder, fqIfdPath string) (ib *IfdBuilder, err error)
GetOrCreateIbFromRootIb returns an IB representing the requested IFD, even if an IB doesn't already exist for it. This function may call itself recursively.
func NewIfdBuilder(ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, ii *exifcommon.IfdIdentity, byteOrder binary.ByteOrder) (ib *IfdBuilder)
func NewIfdBuilderFromExistingChain(rootIfd *Ifd) (firstIb *IfdBuilder)
NewIfdBuilderFromExistingChain creates a chain of IB instances from an IFD chain generated from real data.
func NewIfdBuilderWithExistingIfd(ifd *Ifd) (ib *IfdBuilder)
NewIfdBuilderWithExistingIfd creates a new IB using the same header type information as the given IFD.
func (ib *IfdBuilder) Add(bt *BuilderTag) (err error)
func (ib *IfdBuilder) AddChildIb(childIb *IfdBuilder) (err error)
AddChildIb adds a tag that branches to a new IFD.
func (ib *IfdBuilder) AddStandard(tagId uint16, value interface{}) (err error)
AddStandard quickly and easily composes and adds the tag using the information already known about a tag. Only works with standard tags.
func (ib *IfdBuilder) AddStandardWithName(tagName string, value interface{}) (err error)
AddStandardWithName quickly and easily composes and adds the tag using the information already known about a tag (using the name). Only works with standard tags.
func (ib *IfdBuilder) AddTagsFromExisting(ifd *Ifd, includeTagIds []uint16, excludeTagIds []uint16) (err error)
AddTagsFromExisting does a verbatim copy of the entries in `ifd` to this builder. It excludes child IFDs. These must be added explicitly via `AddChildIb()`.
func (ib *IfdBuilder) ChildWithTagId(childIfdTagId uint16) (childIb *IfdBuilder, err error)
func (ib *IfdBuilder) DeleteAll(tagId uint16) (n int, err error)
func (ib *IfdBuilder) DeleteFirst(tagId uint16) (err error)
func (ib *IfdBuilder) DeleteN(tagId uint16, n int) (err error)
func (ib *IfdBuilder) DumpToStrings() (lines []string)
func (ib *IfdBuilder) Find(tagId uint16) (position int, err error)
func (ib *IfdBuilder) FindN(tagId uint16, maxFound int) (found []int, err error)
func (ib *IfdBuilder) FindTag(tagId uint16) (bt *BuilderTag, err error)
func (ib *IfdBuilder) FindTagWithName(tagName string) (bt *BuilderTag, err error)
func (ib *IfdBuilder) IfdIdentity() *exifcommon.IfdIdentity
func (ib *IfdBuilder) NewBuilderTagFromBuilder(childIb *IfdBuilder) (bt *BuilderTag)
func (ib *IfdBuilder) NextIb() (nextIb *IfdBuilder, err error)
func (ib *IfdBuilder) PrintIfdTree()
func (ib *IfdBuilder) PrintTagTree()
func (ib *IfdBuilder) Replace(tagId uint16, bt *BuilderTag) (err error)
func (ib *IfdBuilder) ReplaceAt(position int, bt *BuilderTag) (err error)
func (ib *IfdBuilder) Set(bt *BuilderTag) (err error)
Set will add a new entry or update an existing entry.
func (ib *IfdBuilder) SetNextIb(nextIb *IfdBuilder) (err error)
func (ib *IfdBuilder) SetStandard(tagId uint16, value interface{}) (err error)
SetStandard quickly and easily composes and adds or replaces the tag using the information already known about a tag. Only works with standard tags.
func (ib *IfdBuilder) SetStandardWithName(tagName string, value interface{}) (err error)
SetStandardWithName quickly and easily composes and adds or replaces the tag using the information already known about a tag (using the name). Only works with standard tags.
▹ Example
▹ Example (Timestamp)
▹ Example (UpdateGps)
func (ib *IfdBuilder) SetThumbnail(data []byte) (err error)
SetThumbnail sets thumbnail data.
NOTES:
func (ib *IfdBuilder) String() string
func (ib *IfdBuilder) Tags() (tags []*BuilderTag)
func (ib *IfdBuilder) Thumbnail() []byte
type IfdBuilderTagValue struct {
// contains filtered or unexported fields
}
func NewIfdBuilderTagValueFromBytes(valueBytes []byte) *IfdBuilderTagValue
func NewIfdBuilderTagValueFromIfdBuilder(ib *IfdBuilder) *IfdBuilderTagValue
func (ibtv IfdBuilderTagValue) Bytes() []byte
func (ibtv IfdBuilderTagValue) Ib() *IfdBuilder
func (ibtv IfdBuilderTagValue) IsBytes() bool
IsBytes returns true if the bytes are populated. This is always the case when we're loaded from a tag in an existing IFD.
func (ibtv IfdBuilderTagValue) IsIb() bool
func (ibtv IfdBuilderTagValue) String() string
IfdByteEncoder converts an IB to raw bytes (for writing) while also figuring out all of the allocations and indirection that is required for extended data.
type IfdByteEncoder struct {
// contains filtered or unexported fields
}
func NewIfdByteEncoder() (ibe *IfdByteEncoder)
func (ibe *IfdByteEncoder) EncodeToExif(ib *IfdBuilder) (data []byte, err error)
EncodeToExif calls EncodeToExifPayload and then packages the result into a complete EXIF block.
▹ Example
func (ibe *IfdByteEncoder) EncodeToExifPayload(ib *IfdBuilder) (data []byte, err error)
EncodeToExifPayload is the base encoding step that transcribes the entire IB structure to its on-disk layout.
func (ibe *IfdByteEncoder) Journal() [][3]string
func (ibe *IfdByteEncoder) PrintJournal()
PrintJournal prints a hierarchical representation of the steps taken during encoding.
func (ibe *IfdByteEncoder) TableSize(entryCount int) uint32
IfdEnumerate is the main enumeration type. It knows how to parse the IFD containers in the EXIF blob.
type IfdEnumerate struct {
// contains filtered or unexported fields
}
func NewIfdEnumerate(ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, ebs ExifBlobSeeker, byteOrder binary.ByteOrder) *IfdEnumerate
NewIfdEnumerate returns a new instance of IfdEnumerate.
func (ie *IfdEnumerate) Collect(rootIfdOffset uint32) (index IfdIndex, err error)
Collect enumerates the different EXIF blocks (called IFDs) and builds out an index struct for referencing all of the parsed data.
func (ie *IfdEnumerate) FurthestOffset() uint32
FurthestOffset returns the furthest offset visited in the EXIF blob. This *does not* account for the locations of any undefined tags since we always evaluate the furthest offset, whether or not the user wants to know it.
We are not willing to incur the cost of actually parsing those tags just to know their length when there are still undefined tags that are out there that we still won't have any idea how to parse, thus making this an approximation regardless of how clever we get.
func (ie *IfdEnumerate) Scan(iiRoot *exifcommon.IfdIdentity, ifdOffset uint32, visitor TagVisitorFn, so *ScanOptions) (med *MiscellaneousExifData, err error)
Scan enumerates the different EXIF blocks (called IFDs). `rootIfdName` will be "IFD" in the TIFF standard.
IfdIndex collects a bunch of IFD and tag information stored in several different ways in order to provide convenient lookups.
type IfdIndex struct {
RootIfd *Ifd
Ifds []*Ifd
Tree map[int]*Ifd
Lookup map[string]*Ifd
}
IfdTagEntry refers to a tag in the loaded EXIF block.
type IfdTagEntry struct {
// contains filtered or unexported fields
}
func (ite *IfdTagEntry) ChildFqIfdPath() string
ChildFqIfdPath returns the complete path of the child IFD along with the numeric suffixes differentiating sibling occurrences of the same type. "0" indices are omitted.
func (ite *IfdTagEntry) ChildIfdName() string
ChildIfdName returns the name of the child IFD
func (ite *IfdTagEntry) ChildIfdPath() string
ChildIfdPath returns the path of the child IFD.
func (ite *IfdTagEntry) Format() (phrase string, err error)
Format returns the tag's value as a string.
func (ite *IfdTagEntry) FormatFirst() (phrase string, err error)
FormatFirst returns the same as Format() but only the first item.
func (ite *IfdTagEntry) GetRawBytes() (rawBytes []byte, err error)
GetRawBytes renders a specific list of bytes from the value in this tag.
func (ite *IfdTagEntry) IfdIdentity() *exifcommon.IfdIdentity
IfdIdentity returns the IfdIdentity associated with this tag.
func (ite *IfdTagEntry) IfdPath() string
IfdPath returns the fully-qualified path of the IFD that owns this tag.
func (ite *IfdTagEntry) IsThumbnailOffset() bool
IsThumbnailOffset returns true if the tag has the IFD and tag-ID of a thumbnail offset.
func (ite *IfdTagEntry) IsThumbnailSize() bool
IsThumbnailSize returns true if the tag has the IFD and tag-ID of a thumbnail size.
func (ite *IfdTagEntry) SetChildIfd(ii *exifcommon.IfdIdentity)
SetChildIfd sets child-IFD information (if we represent a child IFD).
func (ite *IfdTagEntry) String() string
String returns a stringified representation of the struct.
func (ite *IfdTagEntry) TagId() uint16
TagId returns the ID of the tag that we represent. The combination of (IfdPath(), TagId()) is unique.
func (ite *IfdTagEntry) TagName() string
TagName returns the name of the tag. This is determined else and set after the parse (since it's not actually stored in the stream). If it's empty, it is because it is an unknown tag (nonstandard or otherwise unavailable in the tag-index).
func (ite *IfdTagEntry) TagType() exifcommon.TagTypePrimitive
TagType is the type of value for this tag.
func (ite *IfdTagEntry) UnitCount() uint32
UnitCount returns the unit-count of the tag's value.
func (ite *IfdTagEntry) Value() (value interface{}, err error)
Value returns the specific, parsed, typed value from the tag.
IndexedTag describes one index lookup result.
type IndexedTag struct {
// Id is the tag-ID.
Id uint16
// Name is the tag name.
Name string
// IfdPath is the proper IFD path of this tag. This is not fully-qualified.
IfdPath string
// SupportedTypes is an unsorted list of allowed tag-types.
SupportedTypes []exifcommon.TagTypePrimitive
}
func (it *IndexedTag) DoesSupportType(tagType exifcommon.TagTypePrimitive) bool
DoesSupportType returns true if this tag can be found/decoded with this type.
func (it *IndexedTag) GetEncodingType(value interface{}) exifcommon.TagTypePrimitive
GetEncodingType returns the largest type that this tag's value can occupy.
func (it *IndexedTag) Is(ifdPath string, id uint16) bool
Is returns true if this tag matched the given tag ID.
func (it *IndexedTag) IsName(ifdPath, name string) bool
IsName returns true if this tag matches the given tag name.
func (it *IndexedTag) String() string
String returns a descriptive string.
MiscellaneousExifData is reports additional data collected during the parse.
type MiscellaneousExifData struct {
// contains filtered or unexported fields
}
func (med *MiscellaneousExifData) UnknownTags() map[exifcommon.BasicTag]exifcommon.BasicTag
UnknownTags returns the unknown tags encountered during the scan.
ParsedTagVisitor is a callback used if wanting to visit through all tags and child IFDs from the current IFD and going down.
type ParsedTagVisitor func(*Ifd, *IfdTagEntry) error
QueuedIfd is one IFD that has been identified but yet to be processed.
type QueuedIfd struct {
IfdIdentity *exifcommon.IfdIdentity
Offset uint32
Parent *Ifd
// ParentTagIndex is our tag position in the parent IFD, if we had a parent
// (if `ParentIfd` is not nil and we weren't an IFD referenced as a sibling
// instead of as a child).
ParentTagIndex int
}
ScanOptions tweaks parser behavior/choices.
type ScanOptions struct {
}
TagIndex is a tag-lookup facility.
type TagIndex struct {
// contains filtered or unexported fields
}
func NewTagIndex() *TagIndex
NewTagIndex returns a new TagIndex struct.
func (ti *TagIndex) Add(it *IndexedTag) (err error)
Add registers a new tag to be recognized during the parse.
func (ti *TagIndex) FindFirst(id uint16, typeId exifcommon.TagTypePrimitive, ifdIdentities []*exifcommon.IfdIdentity) (it *IndexedTag, err error)
FindFirst looks for the given tag-ID in each of the given IFDs in the given order. If `fqIfdPaths` is `nil` then use a default search order. This defies the standard, which requires each tag to exist in certain IFDs. This is a contingency to make recommendations for malformed data.
Things *can* end badly here, in that the same tag-ID in different IFDs might describe different data and different ata-types, and our decode might then produce binary and non-printable data.
func (ti *TagIndex) Get(ii *exifcommon.IfdIdentity, id uint16) (it *IndexedTag, err error)
Get returns information about the non-IFD tag given a tag ID. `ifdPath` must not be fully-qualified.
func (ti *TagIndex) GetWithName(ii *exifcommon.IfdIdentity, name string) (it *IndexedTag, err error)
GetWithName returns information about the non-IFD tag given a tag name.
func (ti *TagIndex) SetUniversalSearch(flag bool)
SetUniversalSearch enables a fallback to matching tags under *any* IFD.
func (ti *TagIndex) UniversalSearch() bool
UniversalSearch enables a fallback to matching tags under *any* IFD.
TagVisitorFn is called for each tag when enumerating through the EXIF.
type TagVisitorFn func(ite *IfdTagEntry) (err error)
| Name | Synopsis |
|---|---|
| .. | |
| command | |
| exif-read-tool | This tool dumps EXIF information from images. |
| common | |
| undefined | |