1 /*! \file exif-entry.h 2 * \brief Handling EXIF entries 3 */ 4 /* 5 * Copyright (c) 2001 Lutz Mueller <lutz (at) users.sourceforge.net> 6 * 7 * This library is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2 of the License, or (at your option) any later version. 11 * 12 * This library is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with this library; if not, write to the 19 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 20 * Boston, MA 02110-1301 USA. 21 */ 22 23 #ifndef __EXIF_ENTRY_H__ 24 #define __EXIF_ENTRY_H__ 25 26 #ifdef __cplusplus 27 extern "C" { 28 #endif /* __cplusplus */ 29 30 /*! Data found in one EXIF tag. 31 * The #exif_entry_get_value function can provide access to the 32 * formatted contents, or the struct members can be used directly to 33 * access the raw contents. 34 */ 35 typedef struct _ExifEntry ExifEntry; 36 typedef struct _ExifEntryPrivate ExifEntryPrivate; 37 38 #include <libexif/exif-content.h> 39 #include <libexif/exif-format.h> 40 #include <libexif/exif-mem.h> 41 42 /*! Data found in one EXIF tag */ 43 struct _ExifEntry { 44 /*! EXIF tag for this entry */ 45 ExifTag tag; 46 47 /*! Type of data in this entry */ 48 ExifFormat format; 49 50 /*! Number of elements in the array, if this is an array entry. 51 * Contains 1 for non-array data types. */ 52 unsigned long components; 53 54 /*! Pointer to the raw EXIF data for this entry. It is allocated 55 * by #exif_entry_initialize and is NULL beforehand. Data contained 56 * here may be manipulated using the functions in exif-utils.h */ 57 unsigned char *data; 58 59 /*! Number of bytes in the buffer at \c data. This must be no less 60 * than exif_format_get_size(format)*components */ 61 unsigned int size; 62 63 /*! #ExifContent containing this entry. 64 * \see exif_entry_get_ifd */ 65 ExifContent *parent; 66 67 /*! Internal data to be used by libexif itself */ 68 ExifEntryPrivate *priv; 69 }; 70 71 /* Lifecycle */ 72 73 /*! Reserve memory for and initialize a new #ExifEntry. 74 * No memory is allocated for the \c data element of the returned #ExifEntry. 75 * 76 * \return new allocated #ExifEntry, or NULL on error 77 * 78 * \see exif_entry_new_mem, exif_entry_unref 79 */ 80 ExifEntry *exif_entry_new (void); 81 82 /*! Reserve memory for and initialize new #ExifEntry using the specified 83 * memory allocator. 84 * No memory is allocated for the \c data element of the returned #ExifEntry. 85 * 86 * \return new allocated #ExifEntry, or NULL on error 87 * 88 * \see exif_entry_new, exif_entry_unref 89 */ 90 ExifEntry *exif_entry_new_mem (ExifMem *); 91 92 /*! Increase reference counter for #ExifEntry. 93 * 94 * \param[in] entry #ExifEntry 95 * 96 * \see exif_entry_unref 97 */ 98 void exif_entry_ref (ExifEntry *entry); 99 100 /*! Decrease reference counter for #ExifEntry. 101 * When the reference count drops to zero, free the entry. 102 * 103 * \param[in] entry #ExifEntry 104 */ 105 void exif_entry_unref (ExifEntry *entry); 106 107 /*! Actually free the #ExifEntry. 108 * 109 * \deprecated Should not be called directly. Use #exif_entry_ref and 110 * #exif_entry_unref instead. 111 * 112 * \param[in] entry EXIF entry 113 */ 114 void exif_entry_free (ExifEntry *entry); 115 116 /*! Initialize an empty #ExifEntry with default data in the correct format 117 * for the given tag. If the entry is already initialized, this function 118 * does nothing. 119 * This call allocates memory for the \c data element of the given #ExifEntry. 120 * That memory is freed at the same time as the #ExifEntry. 121 * 122 * \param[out] e entry to initialize 123 * \param[in] tag tag number to initialize as 124 */ 125 void exif_entry_initialize (ExifEntry *e, ExifTag tag); 126 127 /*! Fix the type or format of the given EXIF entry to bring it into spec. 128 * If the data for this EXIF tag is in of the wrong type or is in an invalid 129 * format according to the EXIF specification, then it is converted to make it 130 * valid. This may involve, for example, converting an EXIF_FORMAT_LONG into a 131 * EXIF_FORMAT_SHORT. If the tag is unknown, its value is untouched. 132 * 133 * \note Unfortunately, some conversions are to a type with a more restricted 134 * range, which could have the side effect that the converted data becomes 135 * invalid. This is unlikely as the range of each tag in the standard is 136 * designed to encompass all likely data. 137 * 138 * \param[in,out] entry EXIF entry 139 */ 140 void exif_entry_fix (ExifEntry *entry); 141 142 143 /* For your convenience */ 144 145 /*! Return a localized textual representation of the value of the EXIF entry. 146 * This is meant for display to the user. The format of each tag is subject 147 * to change between locales and in newer versions of libexif. Users who 148 * require the tag data in an unambiguous form should access the data members 149 * of the #ExifEntry structure directly. 150 * 151 * \warning The character set of the returned string may be in 152 * the encoding of the current locale or the native encoding 153 * of the camera. 154 * \bug The EXIF_TAG_XP_* tags are currently always returned in UTF-8, 155 * regardless of locale, and code points above U+FFFF are not 156 * supported. 157 * 158 * \param[in] entry EXIF entry 159 * \param[out] val buffer in which to store value 160 * \param[in] maxlen length of the buffer val 161 * \return val pointer 162 */ 163 const char *exif_entry_get_value (ExifEntry *entry, char *val, 164 unsigned int maxlen); 165 166 /*! Dump text representation of #ExifEntry to stdout. 167 * This is intended for diagnostic purposes only. 168 * 169 * \param[in] entry EXIF tag data 170 * \param[in] indent how many levels deep to indent the data 171 */ 172 void exif_entry_dump (ExifEntry *entry, unsigned int indent); 173 174 /*! Return the IFD number of the given #ExifEntry 175 * 176 * \param[in] e an #ExifEntry* 177 * \return #ExifIfd, or #EXIF_IFD_COUNT on error 178 */ 179 #define exif_entry_get_ifd(e) ((e)?exif_content_get_ifd((e)->parent):EXIF_IFD_COUNT) 180 181 #ifdef __cplusplus 182 } 183 #endif /* __cplusplus */ 184 185 #endif /* __EXIF_ENTRY_H__ */ 186
