blob: 1dcdc7364e5e2b34b218c7256d17cfdbe80deecc [file] [log] [blame]
/*! \file exif-entry.h
* \brief Handling EXIF entries
* Copyright (c) 2001 Lutz Mueller <>
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA.
#ifndef __EXIF_ENTRY_H__
#define __EXIF_ENTRY_H__
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/*! Data found in one EXIF tag.
* The #exif_entry_get_value function can provide access to the
* formatted contents, or the struct members can be used directly to
* access the raw contents.
typedef struct _ExifEntry ExifEntry;
typedef struct _ExifEntryPrivate ExifEntryPrivate;
#include <libexif/exif-content.h>
#include <libexif/exif-format.h>
#include <libexif/exif-mem.h>
/*! Data found in one EXIF tag */
struct _ExifEntry {
/*! EXIF tag for this entry */
ExifTag tag;
/*! Type of data in this entry */
ExifFormat format;
/*! Number of elements in the array, if this is an array entry.
* Contains 1 for non-array data types. */
unsigned long components;
/*! Pointer to the raw EXIF data for this entry. It is allocated
* by #exif_entry_initialize and is NULL beforehand. Data contained
* here may be manipulated using the functions in exif-utils.h */
unsigned char *data;
/*! Number of bytes in the buffer at \c data. This must be no less
* than exif_format_get_size(format)*components */
unsigned int size;
/*! #ExifContent containing this entry.
* \see exif_entry_get_ifd */
ExifContent *parent;
/*! Internal data to be used by libexif itself */
ExifEntryPrivate *priv;
/* Lifecycle */
/*! Reserve memory for and initialize a new #ExifEntry.
* No memory is allocated for the \c data element of the returned #ExifEntry.
* \return new allocated #ExifEntry, or NULL on error
* \see exif_entry_new_mem, exif_entry_unref
ExifEntry *exif_entry_new (void);
/*! Reserve memory for and initialize new #ExifEntry using the specified
* memory allocator.
* No memory is allocated for the \c data element of the returned #ExifEntry.
* \return new allocated #ExifEntry, or NULL on error
* \see exif_entry_new, exif_entry_unref
ExifEntry *exif_entry_new_mem (ExifMem *);
/*! Increase reference counter for #ExifEntry.
* \param[in] entry #ExifEntry
* \see exif_entry_unref
void exif_entry_ref (ExifEntry *entry);
/*! Decrease reference counter for #ExifEntry.
* When the reference count drops to zero, free the entry.
* \param[in] entry #ExifEntry
void exif_entry_unref (ExifEntry *entry);
/*! Actually free the #ExifEntry.
* \deprecated Should not be called directly. Use #exif_entry_ref and
* #exif_entry_unref instead.
* \param[in] entry EXIF entry
void exif_entry_free (ExifEntry *entry);
/*! Initialize an empty #ExifEntry with default data in the correct format
* for the given tag. If the entry is already initialized, this function
* does nothing.
* This call allocates memory for the \c data element of the given #ExifEntry.
* That memory is freed at the same time as the #ExifEntry.
* \param[out] e entry to initialize
* \param[in] tag tag number to initialize as
void exif_entry_initialize (ExifEntry *e, ExifTag tag);
/*! Fix the type or format of the given EXIF entry to bring it into spec.
* If the data for this EXIF tag is in of the wrong type or is in an invalid
* format according to the EXIF specification, then it is converted to make it
* valid. This may involve, for example, converting an EXIF_FORMAT_LONG into a
* EXIF_FORMAT_SHORT. If the tag is unknown, its value is untouched.
* \note Unfortunately, some conversions are to a type with a more restricted
* range, which could have the side effect that the converted data becomes
* invalid. This is unlikely as the range of each tag in the standard is
* designed to encompass all likely data.
* \param[in,out] entry EXIF entry
void exif_entry_fix (ExifEntry *entry);
/* For your convenience */
/*! Return a localized textual representation of the value of the EXIF entry.
* This is meant for display to the user. The format of each tag is subject
* to change between locales and in newer versions of libexif. Users who
* require the tag data in an unambiguous form should access the data members
* of the #ExifEntry structure directly.
* \warning The character set of the returned string may be in
* the encoding of the current locale or the native encoding
* of the camera.
* \bug The EXIF_TAG_XP_* tags are currently always returned in UTF-8,
* regardless of locale, and code points above U+FFFF are not
* supported.
* \param[in] entry EXIF entry
* \param[out] val buffer in which to store value
* \param[in] maxlen length of the buffer val
* \return val pointer
const char *exif_entry_get_value (ExifEntry *entry, char *val,
unsigned int maxlen);
/*! Dump text representation of #ExifEntry to stdout.
* This is intended for diagnostic purposes only.
* \param[in] entry EXIF tag data
* \param[in] indent how many levels deep to indent the data
void exif_entry_dump (ExifEntry *entry, unsigned int indent);
/*! Return the IFD number of the given #ExifEntry
* \param[in] e an #ExifEntry*
* \return #ExifIfd, or #EXIF_IFD_COUNT on error
#define exif_entry_get_ifd(e) ((e)?exif_content_get_ifd((e)->parent):EXIF_IFD_COUNT)
#ifdef __cplusplus
#endif /* __cplusplus */
#endif /* __EXIF_ENTRY_H__ */