EXIF library (libexif) API: libexif/exif-content.h File Reference

EXIF library (libexif) API 0.6.25

Data Structures | Macros | Typedefs | Functions
exif-content.h File Reference

Handling EXIF IFDs. More...

`#include <libexif/exif-tag.h>`
`#include <libexif/exif-entry.h>`
`#include <libexif/exif-data.h>`
`#include <libexif/exif-log.h>`
`#include <libexif/exif-mem.h>`

Go to the source code of this file.

## Data Structures
struct | _ExifContent

## Macros
#define | exif_content_get_value(c, t, v, m)
| Return a textual representation of the EXIF data for a tag.

## Typedefs
typedef struct _ExifContent | ExifContent
| Holds all EXIF tags in a single IFD.
typedef struct _ExifContentPrivate | ExifContentPrivate
typedef void(* | ExifContentForeachEntryFunc) (ExifEntry *, void *user_data)

## Functions
ExifContent * | exif_content_new (void)
| Reserve memory for and initialize a new ExifContent.
ExifContent * | exif_content_new_mem (ExifMem *)
| Reserve memory for and initialize new ExifContent using the specified memory allocator.
void | exif_content_ref (ExifContent *content)
| Increase reference counter for ExifContent.
void | exif_content_unref (ExifContent *content)
| Decrease reference counter for ExifContent.
void | exif_content_free (ExifContent *content)
| Actually free the ExifContent.
void | exif_content_add_entry (ExifContent *c, ExifEntry *entry)
| Add an EXIF tag to an IFD.
void | exif_content_remove_entry (ExifContent *c, ExifEntry *e)
| Remove an EXIF tag from an IFD.
ExifEntry * | exif_content_get_entry (ExifContent *content, ExifTag tag)
| Return the ExifEntry in this IFD corresponding to the given tag.
void | exif_content_fix (ExifContent *c)
| Fix the IFD to bring it into specification.
void | exif_content_foreach_entry (ExifContent *content, ExifContentForeachEntryFunc func, void *user_data)
| Executes function on each EXIF tag in this IFD in turn.
ExifIfd | exif_content_get_ifd (ExifContent *c)
| Return the IFD number in which the given ExifContent is found.
void | exif_content_dump (ExifContent *content, unsigned int indent)
| Dump contents of the IFD to stdout.
void | exif_content_log (ExifContent *content, ExifLog *log)
| Set the log message object for this IFD.

## Detailed Description

Handling EXIF IFDs.

## Macro Definition Documentation

## ◆ exif_content_get_value

#define exif_content_get_value | ( |  | c,
|  |  | t,
|  |  | v,
|  |  | m )

Value:
(exif_content_get_entry (c,t) ? \
exif_entry_get_value (exif_content_get_entry (c,t),v,m) : NULL)
exif_content_get_entry
ExifEntry * exif_content_get_entry(ExifContent *content, ExifTag tag)
Return the ExifEntry in this IFD corresponding to the given tag.
Definition exif-content.c:204

Return a textual representation of the EXIF data for a tag.

Parameters

  [in] | c | ExifContent* for an IFD
  [in] | t | ExifTag to return
  [out] | v | char* buffer in which to store value
  [in] | m | unsigned int length of the buffer v

Returns
  the v pointer, or NULL on error

## Function Documentation

## ◆ exif_content_add_entry()

void exif_content_add_entry | ( | ExifContent * | c,
|  | ExifEntry * | entry )

Add an EXIF tag to an IFD.

If this tag already exists in the IFD, this function does nothing.

Precondition
  The "tag" member of the entry must be set on entry.

Parameters

  [out] | c | IFD
  [in] | entry | EXIF entry to add

References _ExifEntry::parent, and _ExifEntry::tag.

## ◆ exif_content_dump()

void exif_content_dump | ( | ExifContent * | content,
|  | unsigned int | indent )

Dump contents of the IFD to stdout.

This is intended for diagnostic purposes only.

Parameters

  [in] | content | IFD data
  [in] | indent | how many levels deep to indent the data

## ◆ exif_content_fix()

void exif_content_fix | ( | ExifContent * | c | ) |

Fix the IFD to bring it into specification.

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

Parameters

  [in,out] | c | EXIF content for an IFD

References EXIF_SUPPORT_LEVEL_MANDATORY, and _ExifContent::parent.

## ◆ exif_content_foreach_entry()

void exif_content_foreach_entry | ( | ExifContent * | content,
|  | ExifContentForeachEntryFunc | func,
|  | void * | user_data )

Executes function on each EXIF tag in this IFD in turn.

The tags will not necessarily be visited in numerical order.

Parameters

  [in,out] | content | IFD over which to iterate
  [in] | func | function to call for each entry
  [in] | user_data | data to pass into func on each call

## ◆ exif_content_free()

void exif_content_free | ( | ExifContent * | content | ) |

Actually free the ExifContent.

Deprecated
  Should not be called directly. Use exif_content_ref and exif_content_unref instead.

Parameters

  [in] | content | ExifContent

## ◆ exif_content_get_entry()

ExifEntry * exif_content_get_entry | ( | ExifContent * | content,
|  | ExifTag | tag )

Return the ExifEntry in this IFD corresponding to the given tag.

This is a pointer into a member of the ExifContent array and must NOT be freed or unrefed by the caller.

Parameters

  [in] | content | EXIF content for an IFD
  [in] | tag | EXIF tag to return

Returns
  ExifEntry of the tag, or NULL on error

References _ExifEntry::tag.

## ◆ exif_content_get_ifd()

ExifIfd exif_content_get_ifd | ( | ExifContent * | c | ) |

Return the IFD number in which the given ExifContent is found.

Parameters

  [in] | c | an ExifContent*

Returns
  IFD number, or EXIF_IFD_COUNT on error

References _ExifContent::parent.

## ◆ exif_content_log()

void exif_content_log | ( | ExifContent * | content,
|  | ExifLog * | log )

Set the log message object for this IFD.

Parameters

  [in] | content | IFD
  [in] | log | ExifLog*

## ◆ exif_content_new()

ExifContent * exif_content_new | ( | void |  | ) |

Reserve memory for and initialize a new ExifContent.

Returns
  new allocated ExifContent, or NULL on error

See also
  exif_content_new_mem, exif_content_unref

## ◆ exif_content_new_mem()

ExifContent * exif_content_new_mem | ( | ExifMem * | mem | ) |

Reserve memory for and initialize new ExifContent using the specified memory allocator.

Returns
  new allocated ExifContent, or NULL on error

See also
  exif_content_new, exif_content_unref

## ◆ exif_content_ref()

void exif_content_ref | ( | ExifContent * | content | ) |

Increase reference counter for ExifContent.

Parameters

  [in] | content | ExifContent

See also
  exif_content_unref

## ◆ exif_content_remove_entry()

void exif_content_remove_entry | ( | ExifContent * | c,
|  | ExifEntry * | e )

Remove an EXIF tag from an IFD.

If this tag does not exist in the IFD, this function does nothing.

Parameters

  [out] | c | IFD
  [in] | e | EXIF entry to remove

References _ExifEntry::parent.

## ◆ exif_content_unref()

void exif_content_unref | ( | ExifContent * | content | ) |

Decrease reference counter for ExifContent.

When the reference count drops to zero, free the content.

Parameters

  [in] | content | ExifContent