exif-data.h File Reference

Defines the ExifData type and the associated functions. More...

#include <libexif/exif-byte-order.h>
#include <libexif/exif-data-type.h>
#include <libexif/exif-ifd.h>
#include <libexif/exif-log.h>
#include <libexif/exif-tag.h>
#include <libexif/exif-content.h>
#include <libexif/exif-mnote-data.h>
#include <libexif/exif-mem.h>

Go to the source code of this file.

Data Structures
struct	_ExifData
	Represents the entire EXIF data found in an image. More...

Macros
#define	exif_data_get_entry(d, t)
	Return an ExifEntry for the given tag if found in any IFD. More...

Typedefs
typedef struct _ExifData	ExifData
	Represents the entire EXIF data found in an image.
typedef struct _ExifDataPrivate	ExifDataPrivate
typedef void(*	ExifDataForeachContentFunc) (ExifContent *, void *user_data)

Enumerations
enum	ExifDataOption { EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS = 1 << 0, EXIF_DATA_OPTION_FOLLOW_SPECIFICATION = 1 << 1, EXIF_DATA_OPTION_DONT_CHANGE_MAKER_NOTE = 1 << 2 }
	Options to configure the behaviour of ExifData. More...

Functions
ExifData *	exif_data_new (void)
	Allocate a new ExifData. More...
ExifData *	exif_data_new_mem (ExifMem *)
	Allocate a new ExifData using the given memory allocator. More...
ExifData *	exif_data_new_from_file (const char *path)
	Allocate a new ExifData and load EXIF data from a JPEG file. More...
ExifData *	exif_data_new_from_data (const unsigned char *data, unsigned int size)
	Allocate a new ExifData and load EXIF data from a memory buffer. More...
void	exif_data_load_data (ExifData *data, const unsigned char *d, unsigned int size)
	Load the ExifData structure from the raw JPEG or EXIF data in the given memory buffer. More...
void	exif_data_save_data (ExifData *data, unsigned char **d, unsigned int *ds)
	Store raw EXIF data representing the ExifData structure into a memory buffer. More...
void	exif_data_ref (ExifData *data)
void	exif_data_unref (ExifData *data)
void	exif_data_free (ExifData *data)
ExifByteOrder	exif_data_get_byte_order (ExifData *data)
	Return the byte order in use by this EXIF structure. More...
void	exif_data_set_byte_order (ExifData *data, ExifByteOrder order)
	Set the byte order to use for this EXIF data. More...
ExifMnoteData *	exif_data_get_mnote_data (ExifData *d)
	Return the MakerNote data out of the EXIF data. More...
void	exif_data_fix (ExifData *d)
	Fix the EXIF data to bring it into specification. More...
void	exif_data_foreach_content (ExifData *data, ExifDataForeachContentFunc func, void *user_data)
	Execute a function on each IFD in turn. More...
const char *	exif_data_option_get_name (ExifDataOption o)
	Return a short textual description of the given ExifDataOption. More...
const char *	exif_data_option_get_description (ExifDataOption o)
	Return a verbose textual description of the given ExifDataOption. More...
void	exif_data_set_option (ExifData *d, ExifDataOption o)
	Set the given option on the given ExifData. More...
void	exif_data_unset_option (ExifData *d, ExifDataOption o)
	Clear the given option on the given ExifData. More...
void	exif_data_set_data_type (ExifData *d, ExifDataType dt)
	Set the data type for the given ExifData. More...
ExifDataType	exif_data_get_data_type (ExifData *d)
	Return the data type for the given ExifData. More...
void	exif_data_dump (ExifData *data)
	Dump all EXIF data to stdout. More...
void	exif_data_log (ExifData *data, ExifLog *log)
	Set the log message object for all IFDs. More...

Detailed Description

Defines the ExifData type and the associated functions.

Macro Definition Documentation

exif_data_get_entry

#define exif_data_get_entry	(		d,
			t
	)

Value:

        (exif_content_get_entry(d->ifd[EXIF_IFD_0],t) ?                 \
         exif_content_get_entry(d->ifd[EXIF_IFD_0],t) :                 \
         exif_content_get_entry(d->ifd[EXIF_IFD_1],t) ?                 \
         exif_content_get_entry(d->ifd[EXIF_IFD_1],t) :                 \
         exif_content_get_entry(d->ifd[EXIF_IFD_EXIF],t) ?              \
         exif_content_get_entry(d->ifd[EXIF_IFD_EXIF],t) :              \
         exif_content_get_entry(d->ifd[EXIF_IFD_GPS],t) ?               \
         exif_content_get_entry(d->ifd[EXIF_IFD_GPS],t) :               \
         exif_content_get_entry(d->ifd[EXIF_IFD_INTEROPERABILITY],t) ?  \
         exif_content_get_entry(d->ifd[EXIF_IFD_INTEROPERABILITY],t) : NULL)

Return an ExifEntry for the given tag if found in any IFD.

Each IFD is searched in turn and the first containing a tag with this number is returned.

Parameters

[in]	d	ExifData
[in]	t	ExifTag

Returns

ExifEntry* if found, else NULL if not found

Enumeration Type Documentation

ExifDataOption

enum ExifDataOption

Options to configure the behaviour of ExifData.

Enumerator
EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS	Act as though unknown tags are not present.
EXIF_DATA_OPTION_FOLLOW_SPECIFICATION	Fix the EXIF tags to follow the spec.
EXIF_DATA_OPTION_DONT_CHANGE_MAKER_NOTE	Leave the MakerNote alone, which could cause it to be corrupted.

Function Documentation

exif_data_dump()

void exif_data_dump

(

ExifData *

data

)

Dump all EXIF data to stdout.

This is intended for diagnostic purposes only.

Parameters

[in]

data

EXIF data

References _ExifData::data, exif_content_dump(), _ExifData::ifd, and _ExifData::size.

exif_data_fix()

void exif_data_fix

(

ExifData *

d

)

Fix the EXIF data to bring it into specification.

Call exif_content_fix on each IFD to fix existing entries, create any new entries that are mandatory but do not yet exist, and remove any entries that are not allowed.

Parameters

[in,out]

d

EXIF data

References exif_data_foreach_content().

exif_data_foreach_content()

void exif_data_foreach_content	(	ExifData *	data,
		ExifDataForeachContentFunc	func,
		void *	user_data
	)

Execute a function on each IFD in turn.

Parameters

[in]	data	EXIF data over which to iterate
[in]	func	function to call for each entry
[in]	user_data	data to pass into func on each call

Referenced by exif_data_fix(), and exif_data_set_byte_order().

exif_data_get_byte_order()

ExifByteOrder exif_data_get_byte_order

(

ExifData *

data

)

Return the byte order in use by this EXIF structure.

Parameters

[in]

data

EXIF data

Returns

byte order

Referenced by exif_entry_get_value(), and exif_entry_initialize().

exif_data_get_data_type()

ExifDataType exif_data_get_data_type

(

ExifData *

d

)

Return the data type for the given ExifData.

Parameters

[in]

d

EXIF data

Returns

data type, or #EXIF_DATA_TYPE_UNKNOWN on error

Referenced by exif_content_fix().

exif_data_get_mnote_data()

ExifMnoteData* exif_data_get_mnote_data

(

ExifData *

d

)

Return the MakerNote data out of the EXIF data.

Only certain MakerNote formats that are recognized by libexif are supported. The pointer references a member of the ExifData structure and must NOT be freed by the caller.

Parameters

[in]

d

EXIF data

Returns

MakerNote data, or NULL if not found or not supported

exif_data_load_data()

void exif_data_load_data	(	ExifData *	data,
		const unsigned char *	d,
		unsigned int	size
	)

Load the ExifData structure from the raw JPEG or EXIF data in the given memory buffer.

If the EXIF data contains a recognized MakerNote, it is loaded and stored as well for later retrieval by exif_data_get_mnote_data. If the EXIF_DATA_OPTION_FOLLOW_SPECIFICATION option has been set on this ExifData, then the tags are automatically fixed after loading (by calling exif_data_fix).

Parameters

[in,out]	data	EXIF data
[in]	d	pointer to raw JPEG or EXIF data
[in]	size	number of bytes of data at d

Referenced by exif_data_new_from_data(), and exif_loader_get_data().

exif_data_log()

void exif_data_log	(	ExifData *	data,
		ExifLog *	log
	)

Set the log message object for all IFDs.

Parameters

[in]	data	EXIF data
[in]	log	ExifLog

Referenced by exif_loader_get_data().

exif_data_new()

ExifData* exif_data_new

(

void

)

Allocate a new ExifData.

The ExifData contains an empty ExifContent for each IFD and the default set of options, which has EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS and EXIF_DATA_OPTION_FOLLOW_SPECIFICATION set.

Returns

allocated ExifData, or NULL on error

References exif_data_new_mem(), exif_mem_new_default(), and exif_mem_unref().

Referenced by exif_data_new_from_data().

exif_data_new_from_data()

ExifData* exif_data_new_from_data	(	const unsigned char *	data,
		unsigned int	size
	)

Allocate a new ExifData and load EXIF data from a memory buffer.

Parameters

[in]	data	pointer to raw JPEG or EXIF data
[in]	size	number of bytes of data at data

Returns

allocated ExifData, or NULL on error

References exif_data_load_data(), and exif_data_new().

exif_data_new_from_file()

ExifData* exif_data_new_from_file

(

const char *

path

)

Allocate a new ExifData and load EXIF data from a JPEG file.

Uses an ExifLoader internally to do the loading.

Parameters

[in]

path

filename including path

Returns

allocated ExifData, or NULL on error

References exif_loader_get_data(), exif_loader_new(), exif_loader_unref(), and exif_loader_write_file().

exif_data_new_mem()

ExifData* exif_data_new_mem

(

ExifMem *

)

Allocate a new ExifData using the given memory allocator.

The ExifData contains an empty ExifContent for each IFD and the default set of options, which has EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS and EXIF_DATA_OPTION_FOLLOW_SPECIFICATION set.

Returns

allocated ExifData, or NULL on error

Referenced by exif_data_new(), and exif_loader_get_data().

exif_data_option_get_description()

const char* exif_data_option_get_description

(

ExifDataOption

o

)

Return a verbose textual description of the given ExifDataOption.

Parameters

[in]

o

option

Returns

verbose localized textual description of the option

exif_data_option_get_name()

const char* exif_data_option_get_name

(

ExifDataOption

o

)

Return a short textual description of the given ExifDataOption.

Parameters

[in]

o

option

Returns

localized textual description of the option

exif_data_save_data()

void exif_data_save_data	(	ExifData *	data,
		unsigned char **	d,
		unsigned int *	ds
	)

Store raw EXIF data representing the ExifData structure into a memory buffer.

The buffer is allocated by this function and must subsequently be freed by the caller using the matching free function as used by the ExifMem in use by this ExifData.

Parameters

[in]	data	EXIF data
[out]	d	pointer to buffer pointer containing raw EXIF data on return
[out]	ds	pointer to variable to hold the number of bytes of data at d, or set to 0 on error

References EXIF_BYTE_ORDER_INTEL, exif_set_long(), and exif_set_short().

exif_data_set_byte_order()

void exif_data_set_byte_order	(	ExifData *	data,
		ExifByteOrder	order
	)

Set the byte order to use for this EXIF data.

If any tags already exist (including MakerNote tags) they are are converted to the specified byte order.

Parameters

[in,out]	data	EXIF data
[in]	order	byte order

References exif_data_foreach_content().

exif_data_set_data_type()

void exif_data_set_data_type	(	ExifData *	d,
		ExifDataType	dt
	)

Set the data type for the given ExifData.

Parameters

[in]	d	EXIF data
[in]	dt	data type

exif_data_set_option()

void exif_data_set_option	(	ExifData *	d,
		ExifDataOption	o
	)

Set the given option on the given ExifData.

Parameters

[in]	d	EXIF data
[in]	o	option

exif_data_unset_option()

void exif_data_unset_option	(	ExifData *	d,
		ExifDataOption	o
	)

Clear the given option on the given ExifData.

Parameters

[in]	d	EXIF data
[in]	o	option