exif-content.c

Go to the documentation of this file.

/* exif-content.c
 *
 * Copyright (c) 2001 Lutz Mueller <lutz@users.sourceforge.net>
 *
 * 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
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * 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.
 *
 * SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
#include <config.h>
 
#include <libexif/exif-content.h>
#include <libexif/exif-system.h>
 
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
 
/* unused constant
 * static const unsigned char ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
 */
 
struct _ExifContentPrivate
{
        unsigned int ref_count;
 
        ExifMem *mem;
        ExifLog *log;
};
 
ExifContent *
exif_content_new (void)
{
        ExifMem *mem = exif_mem_new_default ();
        ExifContent *content = exif_content_new_mem (mem);
 
        exif_mem_unref (mem);
 
        return content;
}
 
ExifContent *
exif_content_new_mem (ExifMem *mem)
{
        ExifContent *content;
 
        if (!mem) return NULL;
 
        content = exif_mem_alloc (mem, (ExifLong) sizeof (ExifContent));
        if (!content)
                return NULL;
        content->priv = exif_mem_alloc (mem,
                                (ExifLong) sizeof (ExifContentPrivate));
        if (!content->priv) {
                exif_mem_free (mem, content);
                return NULL;
        }
 
        content->priv->ref_count = 1;
 
        content->priv->mem = mem;
        exif_mem_ref (mem);
 
        return content;
}
 
void
exif_content_ref (ExifContent *content)
{
        if (!content)
                return;
 
        content->priv->ref_count++;
}
 
void
exif_content_unref (ExifContent *content)
{
        if (!content)
                return;
 
        content->priv->ref_count--;
        if (!content->priv->ref_count)
                exif_content_free (content);
}
 
void
exif_content_free (ExifContent *content)
{
        ExifMem *mem = (content && content->priv) ? content->priv->mem : NULL;
        unsigned int i;
 
        if (!content) return;
 
        for (i = 0; i < content->count; i++)
                exif_entry_unref (content->entries[i]);
        exif_mem_free (mem, content->entries);
 
        if (content->priv) {
                exif_log_unref (content->priv->log);
        }
 
        exif_mem_free (mem, content->priv);
        exif_mem_free (mem, content);
        exif_mem_unref (mem);
}
 
void
exif_content_dump (ExifContent *content, unsigned int indent)
{
        char buf[1024];
        unsigned int i, l;
 
        if (!content)
                return;
 
        l = MIN(sizeof(buf)-1, 2*indent);
        memset(buf, ' ', l);
        buf[l] = '\0';
 
        printf ("%sDumping exif content (%u entries)...\n", buf,
                content->count);
        for (i = 0; i < content->count; i++)
                exif_entry_dump (content->entries[i], indent + 1);
}
 
void
exif_content_add_entry (ExifContent *c, ExifEntry *entry)
{
        ExifEntry **entries;
        if (!c || !c->priv || !entry || entry->parent) return;
 
        /* One tag can only be added once to an IFD. */
        if (exif_content_get_entry (c, entry->tag)) {
                exif_log (c->priv->log, EXIF_LOG_CODE_DEBUG, "ExifContent",
                        "An attempt has been made to add "
                        "the tag '%s' twice to an IFD. This is against "
                        "specification.", exif_tag_get_name (entry->tag));
                return;
        }
 
        entries = exif_mem_realloc (c->priv->mem,
                c->entries, sizeof (ExifEntry*) * (c->count + 1));
        if (!entries) return;
        entry->parent = c;
        entries[c->count++] = entry;
        c->entries = entries;
        exif_entry_ref (entry);
}
 
void
exif_content_remove_entry (ExifContent *c, ExifEntry *e)
{
        unsigned int i;
        ExifEntry **t, *temp;
 
        if (!c || !c->priv || !e || (e->parent != c)) return;
 
        /* Search the entry */
        for (i = 0; i < c->count; i++)
                        if (c->entries[i] == e)
                                        break;
 
        if (i == c->count)
                        return;
 
        /* Remove the entry */
        temp = c->entries[c->count-1];
        if (c->count > 1) {
                t = exif_mem_realloc (c->priv->mem, c->entries,
                                        sizeof(ExifEntry*) * (c->count - 1));
                if (!t) {
                        return;
                }
                c->entries = t;
                c->count--;
                if (i != c->count) { /* we deallocated the last slot already */ 
                        memmove (&t[i], &t[i + 1], sizeof (ExifEntry*) * (c->count - i - 1));
                        t[c->count-1] = temp;
                } 
        } else {
                exif_mem_free (c->priv->mem, c->entries);
                c->entries = NULL;
                c->count = 0;
        }
        e->parent = NULL;
        exif_entry_unref (e);
}
 
ExifEntry *
exif_content_get_entry (ExifContent *content, ExifTag tag)
{
        unsigned int i;
 
        if (!content)
                return (NULL);
 
        for (i = 0; i < content->count; i++)
                if (content->entries[i]->tag == tag)
                        return (content->entries[i]);
        return (NULL);
}
 
void
exif_content_foreach_entry (ExifContent *content,
                            ExifContentForeachEntryFunc func, void *data)
{
        unsigned int i;
 
        if (!content || !func)
                return;
 
        for (i = 0; i < content->count; i++)
                func (content->entries[i], data);
}
 
void
exif_content_log (ExifContent *content, ExifLog *log)
{
        if (!content || !content->priv || !log || content->priv->log == log)
                return;
 
        if (content->priv->log) exif_log_unref (content->priv->log);
        content->priv->log = log;
        exif_log_ref (log);
}
 
ExifIfd
exif_content_get_ifd (ExifContent *c)
{
        if (!c || !c->parent) return EXIF_IFD_COUNT;
 
        return 
                ((c)->parent->ifd[EXIF_IFD_EXIF] == (c)) ? EXIF_IFD_EXIF :
                ((c)->parent->ifd[EXIF_IFD_0] == (c)) ? EXIF_IFD_0 :
                ((c)->parent->ifd[EXIF_IFD_1] == (c)) ? EXIF_IFD_1 :
                ((c)->parent->ifd[EXIF_IFD_GPS] == (c)) ? EXIF_IFD_GPS :
                ((c)->parent->ifd[EXIF_IFD_INTEROPERABILITY] == (c)) ? EXIF_IFD_INTEROPERABILITY :
                EXIF_IFD_COUNT;
}
 
static void
fix_func (ExifEntry *e, void *UNUSED(data))
{
        exif_entry_fix (e);
}
 
static void
remove_not_recorded (ExifEntry *e, void *UNUSED(data))
{
        ExifIfd ifd = exif_entry_get_ifd(e) ;
        ExifContent *c = e->parent;
        ExifDataType dt = exif_data_get_data_type (c->parent);
        ExifTag t = e->tag;
 
        if (exif_tag_get_support_level_in_ifd (t, ifd, dt) ==
                         EXIF_SUPPORT_LEVEL_NOT_RECORDED) {
                exif_log (c->priv->log, EXIF_LOG_CODE_DEBUG, "exif-content",
                                "Tag 0x%04x is not recorded in IFD '%s' and has therefore been "
                                "removed.", t, exif_ifd_get_name (ifd));
                exif_content_remove_entry (c, e);
        }
 
}
 
void
exif_content_fix (ExifContent *c)
{
        ExifIfd ifd = exif_content_get_ifd (c);
        ExifDataType dt;
        ExifEntry *e;
        unsigned int i, num;
 
        if (!c)
                return;
 
        dt = exif_data_get_data_type (c->parent);
 
        /*
         * First of all, fix all existing entries.
         */
        exif_content_foreach_entry (c, fix_func, NULL);
 
        /*
         * Go through each tag and if it's not recorded, remove it. If one
         * is removed, exif_content_foreach_entry() will skip the next entry,
         * so if this happens do the loop again from the beginning to ensure
         * they're all checked. This could be avoided if we stop relying on
         * exif_content_foreach_entry but loop intelligently here.
         */
        do {
                num = c->count;
                exif_content_foreach_entry (c, remove_not_recorded, NULL);
        } while (num != c->count);
 
        /*
         * Then check for non-existing mandatory tags and create them if needed
         */
        num = exif_tag_table_count();
        for (i = 0; i < num; ++i) {
                const ExifTag t = exif_tag_table_get_tag (i);
                if (exif_tag_get_support_level_in_ifd (t, ifd, dt) ==
                        EXIF_SUPPORT_LEVEL_MANDATORY) {
                        if (exif_content_get_entry (c, t))
                                /* This tag already exists */
                                continue;
                        exif_log (c->priv->log, EXIF_LOG_CODE_DEBUG, "exif-content",
                                        "Tag '%s' is mandatory in IFD '%s' and has therefore been added.",
                                        exif_tag_get_name_in_ifd (t, ifd), exif_ifd_get_name (ifd));
                        e = exif_entry_new ();
                        exif_content_add_entry (c, e);
                        exif_entry_initialize (e, t);
                        exif_entry_unref (e);
                }
        }
}