88 lines
3.3 KiB
C
88 lines
3.3 KiB
C
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/*! \file exif.h exif/exif.h
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* \brief Dummy header file for documentation purposes
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* \date 2007
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* \author Hans Ulrich Niedermann, et. al.
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*
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* \mainpage The libexif library
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*
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* \section general_notes General Notes
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*
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* This documentation is work in progress, as is the code itself.
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*
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* \section using_libexif Using libexif
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*
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* \#include <libexif/exif-data.h>
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*
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* libexif provides a libexif.pc file for use with pkgconfig on the
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* libexif installation. If you are using libtool to build your
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* package, you can also make use of libexif-uninstalled.pc.
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*
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* An application using libexif would typically first create an #ExifLoader to
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* load EXIF data into memory. From there, it would extract that data as
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* an #ExifData to start manipulating it. Each IFD is represented by its own
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* #ExifContent within that #ExifData, which contains all the tag data in
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* #ExifEntry form. If the MakerNote data is required, an #ExifMnoteData
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* can be extracted from the #ExifData and manipulated with the MakerNote
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* functions.
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*
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* libexif is written in C using an object-based style that defines
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* sets of functions that operate on each data structure.
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*
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* \section data_structures Primary Data Structures
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*
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* #ExifLoader
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* State maintained by the loader interface while importing EXIF data
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* from an external file or memory
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*
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* #ExifData
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* The entirety of EXIF data found in an image
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*
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* #ExifContent
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* All EXIF tags in a single IFD
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*
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* #ExifEntry
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* Data found in a single EXIF tag
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*
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* #ExifMnoteData
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* All data found in the MakerNote tag
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*
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* #ExifLog
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* State maintained by the logging interface
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*
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* \section string_conventions String Conventions
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*
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* Strings are 8 bit characters ("char*"). When libexif is compiled with
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* NLS, character set and encoding are as set in the current locale,
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* except for strings that come directly from the data in EXIF
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* tags which are generally returned in raw form. Most EXIF strings are
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* defined to be plain 7-bit ASCII so this raw form should be acceptable in
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* any UNIX locale, but some software ignores the specification and
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* writes 8-bit characters. It is up to the application to detect this
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* and deal with it intelligently.
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*
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* \section memory_management Memory Management Patterns
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*
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* For pointers to data objects, libexif uses reference counting. The
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* pattern is to use the foo_new() function to create a data object,
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* foo_ref() to increase the reference counter, and foo_unref() to
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* decrease the reference counter and possibly free(3)ing the memory.
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*
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* Libexif by default relies on the calloc(3), realloc(3), and free(3)
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* functions, but the libexif user can tell libexif to use their
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* special memory management functions at runtime.
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*
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* \section thread_safety Thread Safety
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*
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* libexif is thread safe when the underlying C library is also thread safe.
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* Some C libraries may require defining a special macro (like _REENTRANT)
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* to ensure this, or may require linking to a special thread-safe version of
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* the library.
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*
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* The programmer must ensure that each object allocated by libexif is only
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* used in a single thread at once. For example, an ExifData* allocated
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* in one thread can't be used in a second thread if there is any chance
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* that the first thread could use it at the same time. Multiple threads
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* can use libexif without issues if they never share handles.
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*
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*/
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