exif-mnote-data-olympus.c

Go to the documentation of this file.

/* exif-mnote-data-olympus.c
 *
 * Copyright (c) 2002, 2003 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 "exif-mnote-data-olympus.h"
 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
 
#include <libexif/exif-utils.h>
#include <libexif/exif-data.h>
 
/* Uncomment this to fix a problem with Sanyo MakerNotes. It's probably best
 * not to in most cases because it seems to only affect the thumbnail tag
 * which is duplicated in IFD 1, and fixing the offset could actually cause
 * problems with other software that expects the broken form.
 */
/*#define EXIF_OVERCOME_SANYO_OFFSET_BUG */
 
#define CHECKOVERFLOW(offset,datasize,structsize) (( (offset) >= (datasize)) || ((structsize) > (datasize)) || ((offset) > (datasize) - (structsize) ))
 
static enum OlympusVersion
exif_mnote_data_olympus_identify_variant (const unsigned char *buf,
                unsigned int buf_size);
 
 
static void
exif_mnote_data_olympus_clear (ExifMnoteDataOlympus *n)
{
        ExifMnoteData *d = (ExifMnoteData *) n;
        unsigned int i;
 
        if (!n) return;
 
        if (n->entries) {
                for (i = 0; i < n->count; i++)
                        if (n->entries[i].data) {
                                exif_mem_free (d->mem, n->entries[i].data);
                                n->entries[i].data = NULL;
                        }
                exif_mem_free (d->mem, n->entries);
                n->entries = NULL;
                n->count = 0;
        }
}
 
static void
exif_mnote_data_olympus_free (ExifMnoteData *n)
{
        if (!n) return;
 
        exif_mnote_data_olympus_clear ((ExifMnoteDataOlympus *) n);
}
 
static char *
exif_mnote_data_olympus_get_value (ExifMnoteData *d, unsigned int i, char *val, unsigned int maxlen)
{
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
 
        if (!d || !val) return NULL;
        if (i >= n->count) return NULL;
/*
        exif_log (d->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                  "Querying value for tag '%s'...",
                  mnote_olympus_tag_get_name (n->entries[i].tag));
*/
        return mnote_olympus_entry_get_value (&n->entries[i], val, maxlen);
}
 
 
 
 
static void
exif_mnote_data_olympus_save (ExifMnoteData *ne,
                unsigned char **buf, unsigned int *buf_size)
{
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) ne;
        size_t i, o, s, doff, base = 0, o2 = 6 + 2;
        size_t datao = 0;
        unsigned char *t;
        size_t ts;
 
        if (!n || !buf || !buf_size) return;
 
        /*
         * Allocate enough memory for all entries and the number of entries.
         */
        *buf_size = 6 + 2 + 2 + n->count * 12;
        switch (n->version) {
        case olympusV1:
        case sanyoV1:
        case epsonV1:
                *buf = exif_mem_alloc (ne->mem, *buf_size);
                if (!*buf) {
                        EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", *buf_size);
                        return;
                }
 
                /* Write the header and the number of entries. */
                strcpy ((char *)*buf, n->version==sanyoV1?"SANYO":
                                        (n->version==epsonV1?"EPSON":"OLYMP"));
                exif_set_short (*buf + 6, n->order, (ExifShort) 1);
                datao = n->offset;
                break;
 
        case olympusV2:
                *buf_size += 8-6 + 4;
                *buf = exif_mem_alloc (ne->mem, *buf_size);
                if (!*buf) {
                        EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", *buf_size);
                        return;
                }
 
                /* Write the header and the number of entries. */
                strcpy ((char *)*buf, "OLYMPUS");
                exif_set_short (*buf + 8, n->order, (ExifShort) (
                        (n->order == EXIF_BYTE_ORDER_INTEL) ?
                        ('I' << 8) | 'I' :
                        ('M' << 8) | 'M'));
                exif_set_short (*buf + 10, n->order, (ExifShort) 3);
                o2 += 4;
                break;
 
        case nikonV1: 
                base = MNOTE_NIKON1_TAG_BASE;
 
                /* v1 has offsets based to main IFD, not makernote IFD */
                datao += n->offset + 10;
                /* subtract the size here, so the increment in the next case will not harm us */
                *buf_size -= 8 + 2;
                /* fall through */
        /* Fall through to nikonV2 handler */
        case nikonV2: 
        /* Write out V0 files in V2 format */
        case nikonV0: 
                *buf_size += 8 + 2;
                *buf_size += 4; /* Next IFD pointer */
                *buf = exif_mem_alloc (ne->mem, *buf_size);
                if (!*buf) {
                        EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", *buf_size);
                        return;
                }
 
                /* Write the header and the number of entries. */
                strcpy ((char *)*buf, "Nikon");
                (*buf)[6] = (unsigned char)n->version;
 
                if (n->version != nikonV1) {
                        exif_set_short (*buf + 10, n->order, (ExifShort) (
                                (n->order == EXIF_BYTE_ORDER_INTEL) ?
                                ('I' << 8) | 'I' :
                                ('M' << 8) | 'M'));
                        exif_set_short (*buf + 12, n->order, (ExifShort) 0x2A);
                        exif_set_long (*buf + 14, n->order, (ExifShort) 8);
                        o2 += 2 + 8;
                }
                datao -= 10;
                /* Reset next IFD pointer */
                exif_set_long (*buf + o2 + 2 + n->count * 12, n->order, 0);
                break;
 
        default:
                return;
        }
 
        exif_set_short (*buf + o2, n->order, (ExifShort) n->count);
        o2 += 2;
 
        /* Save each entry */
        for (i = 0; i < n->count; i++) {
                o = o2 + i * 12;
                exif_set_short (*buf + o + 0, n->order,
                                (ExifShort) (n->entries[i].tag - base));
                exif_set_short (*buf + o + 2, n->order,
                                (ExifShort) n->entries[i].format);
                exif_set_long  (*buf + o + 4, n->order,
                                n->entries[i].components);
                o += 8;
                s = exif_format_get_size (n->entries[i].format) *
                                                n->entries[i].components;
                if (s > 65536) {
                        /* Corrupt data: EXIF data size is limited to the
                         * maximum size of a JPEG segment (64 kb).
                         */
                        continue;
                }
                if (s > 4) {
                        doff = *buf_size;
                        ts = *buf_size + s;
                        t = exif_mem_realloc (ne->mem, *buf,
                                                 sizeof (char) * ts);
                        if (!t) {
                                EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", ts);
                                return;
                        }
                        *buf = t;
                        *buf_size = ts;
                        exif_set_long (*buf + o, n->order, datao + doff);
                } else
                        doff = o;
 
                /* Write the data. */
                if (n->entries[i].data) {
                        memcpy (*buf + doff, n->entries[i].data, s);
                } else {
                        /* Most certainly damaged input file */
                        memset (*buf + doff, 0, s);
                }
        }
}
 
static void
exif_mnote_data_olympus_load (ExifMnoteData *en,
                              const unsigned char *buf, unsigned int buf_size)
{
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) en;
        ExifShort c;
        size_t i, tcount, o, o2, datao = 6, base = 0;
 
        if (!n) return;
 
        if (!buf || !buf_size) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                          "ExifMnoteDataOlympus", "Short MakerNote");
                return;
        }
        o2 = 6 + n->offset; /* Start of interesting data */
        if (CHECKOVERFLOW(o2,buf_size,10)) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                          "ExifMnoteDataOlympus", "Short MakerNote");
                return;
        }
 
        /*
         * Olympus headers start with "OLYMP" and need to have at least
         * a size of 22 bytes (6 for 'OLYMP', 2 other bytes, 2 for the
         * number of entries, and 12 for one entry.
         *
         * Sanyo format is identical and uses identical tags except that
         * header starts with "SANYO".
         *
         * Epson format is identical and uses identical tags except that
         * header starts with "EPSON".
         *
         * Nikon headers start with "Nikon" (6 bytes including '\0'), 
         * version number (1 or 2).
         * 
         * Version 1 continues with 0, 1, 0, number_of_tags,
         * or just with number_of_tags (models D1H, D1X...).
         * 
         * Version 2 continues with an unknown byte (0 or 10),
         * two unknown bytes (0), "MM" or "II", another byte 0 and 
         * lastly 0x2A.
         */
        n->version = exif_mnote_data_olympus_identify_variant(buf+o2, buf_size-o2);
        switch (n->version) {
        case olympusV1:
        case sanyoV1:
        case epsonV1:
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                        "Parsing Olympus/Sanyo/Epson maker note v1...");
 
                /* The number of entries is at position 8. */
                if (buf[o2 + 6] == 1)
                        n->order = EXIF_BYTE_ORDER_INTEL;
                else if (buf[o2 + 6 + 1] == 1)
                        n->order = EXIF_BYTE_ORDER_MOTOROLA;
                o2 += 8;
                c = exif_get_short (buf + o2, n->order);
                if ((!(c & 0xFF)) && (c > 0x500)) {
                        if (n->order == EXIF_BYTE_ORDER_INTEL) {
                                n->order = EXIF_BYTE_ORDER_MOTOROLA;
                        } else {
                                n->order = EXIF_BYTE_ORDER_INTEL;
                        }
                }
                break;
 
        case olympusV2:
                /* Olympus S760, S770 */
                datao = o2;
                o2 += 8;
                if (CHECKOVERFLOW(o2,buf_size,4)) return;
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                        "Parsing Olympus maker note v2 (0x%02x, %02x, %02x, %02x)...",
                        buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3]);
 
                if ((buf[o2] == 'I') && (buf[o2 + 1] == 'I'))
                        n->order = EXIF_BYTE_ORDER_INTEL;
                else if ((buf[o2] == 'M') && (buf[o2 + 1] == 'M'))
                        n->order = EXIF_BYTE_ORDER_MOTOROLA;
 
                /* The number of entries is at position 8+4. */
                o2 += 4;
                break;
 
        case nikonV1:
                o2 += 6;
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                        "Parsing Nikon maker note v1 (0x%02x, %02x, %02x, "
                        "%02x)...",
                        buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3]);
 
                /* Skip version number */
                o2 += 1;
 
                /* Skip an unknown byte (00 or 0A). */
                o2 += 1;
 
                base = MNOTE_NIKON1_TAG_BASE;
                /* Fix endianness, if needed */
                c = exif_get_short (buf + o2, n->order);
                if ((!(c & 0xFF)) && (c > 0x500)) {
                        if (n->order == EXIF_BYTE_ORDER_INTEL) {
                                n->order = EXIF_BYTE_ORDER_MOTOROLA;
                        } else {
                                n->order = EXIF_BYTE_ORDER_INTEL;
                        }
                }
                break;
 
        case nikonV2:
                o2 += 6;
                if (CHECKOVERFLOW(o2,buf_size,12)) return;
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                        "Parsing Nikon maker note v2 (0x%02x, %02x, %02x, "
                        "%02x, %02x, %02x, %02x, %02x)...",
                        buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3],
                        buf[o2 + 4], buf[o2 + 5], buf[o2 + 6], buf[o2 + 7]);
 
                /* Skip version number */
                o2 += 1;
 
                /* Skip an unknown byte (00 or 0A). */
                o2 += 1;
 
                /* Skip 2 unknown bytes (00 00). */
                o2 += 2;
 
                /*
                 * Byte order. From here the data offset
                 * gets calculated.
                 */
                datao = o2;
                if (!strncmp ((char *)&buf[o2], "II", 2))
                        n->order = EXIF_BYTE_ORDER_INTEL;
                else if (!strncmp ((char *)&buf[o2], "MM", 2))
                        n->order = EXIF_BYTE_ORDER_MOTOROLA;
                else {
                        exif_log (en->log, EXIF_LOG_CODE_DEBUG,
                                "ExifMnoteDataOlympus", "Unknown "
                                "byte order '%c%c'", buf[o2],
                                buf[o2 + 1]);
                        return;
                }
                o2 += 2;
 
                /* Skip 2 unknown bytes (00 2A). */
                o2 += 2;
 
                /* Go to where the number of entries is. */
                if (CHECKOVERFLOW(o2,buf_size,exif_get_long (buf + o2, n->order))) return;
                o2 = datao + exif_get_long (buf + o2, n->order);
                break;
 
        case nikonV0:
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                        "Parsing Nikon maker note v0 (0x%02x, %02x, %02x, "
                        "%02x, %02x, %02x, %02x, %02x)...",
                        buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3], 
                        buf[o2 + 4], buf[o2 + 5], buf[o2 + 6], buf[o2 + 7]);
                /* 00 1b is # of entries in Motorola order - the rest should also be in MM order */
                n->order = EXIF_BYTE_ORDER_MOTOROLA;
                break;
 
        default:
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
                        "Unknown Olympus variant %i.", n->version);
                return;
        }
 
        /* Sanity check the offset */
        if (CHECKOVERFLOW(o2,buf_size,2)) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                          "ExifMnoteOlympus", "Short MakerNote");
                return;
        }
 
        /* Read the number of tags */
        c = exif_get_short (buf + o2, n->order);
        o2 += 2;
 
        /* Just use an arbitrary max tag limit here to avoid needing to much memory or time. There are 150 named tags currently.
         * The format allows specifying the same range of memory as often as it can, so this multiplies quickly. */
        if (c > 300) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifMnoteOlympus", "Too much tags (%d) in Olympus MakerNote", c);
                return;
        }
 
        /* Remove any old entries */
        exif_mnote_data_olympus_clear (n);
 
        /* Reserve enough space for all the possible MakerNote tags */
        n->entries = exif_mem_alloc (en->mem, sizeof (MnoteOlympusEntry) * c);
        if (!n->entries) {
                EXIF_LOG_NO_MEMORY(en->log, "ExifMnoteOlympus", sizeof (MnoteOlympusEntry) * c);
                return;
        }
 
        /* Parse all c entries, storing ones that are successfully parsed */
        tcount = 0;
        for (i = c, o = o2; i; --i, o += 12) {
                size_t s;
                memset(&n->entries[tcount], 0, sizeof(MnoteOlympusEntry));
                if (CHECKOVERFLOW(o, buf_size, 12)) {
                        exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                                  "ExifMnoteOlympus", "Short MakerNote");
                        break;
                }
 
            n->entries[tcount].tag        = exif_get_short (buf + o, n->order) + base;
            n->entries[tcount].format     = exif_get_short (buf + o + 2, n->order);
            n->entries[tcount].components = exif_get_long (buf + o + 4, n->order);
            n->entries[tcount].order      = n->order;
 
            exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteOlympus",
                      "Loading entry 0x%x ('%s')...", n->entries[tcount].tag,
                      mnote_olympus_tag_get_name (n->entries[tcount].tag));
/*          exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteOlympus",
                            "0x%x %d %ld*(%d)",
                    n->entries[tcount].tag,
                    n->entries[tcount].format,
                    n->entries[tcount].components,
                    (int)exif_format_get_size(n->entries[tcount].format)); */
 
            /* Check if we overflow the multiplication. Use buf_size as the max size for integer overflow detection,
             * we will check the buffer sizes closer later. */
            if (exif_format_get_size (n->entries[tcount].format) &&
                buf_size / exif_format_get_size (n->entries[tcount].format) < n->entries[tcount].components
            ) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifMnoteOlympus", "Tag size overflow detected (%u * %lu)", exif_format_get_size (n->entries[tcount].format), n->entries[tcount].components);
                continue;
            }
            /*
             * Size? If bigger than 4 bytes, the actual data is not
             * in the entry but somewhere else (offset).
             */
            s = exif_format_get_size (n->entries[tcount].format) *
                                         n->entries[tcount].components;
                n->entries[tcount].size = s;
                if (s) {
                        size_t dataofs = o + 8;
                        if (s > 4) {
                                /* The data in this case is merely a pointer */
                                dataofs = exif_get_long (buf + dataofs, n->order) + datao;
#ifdef EXIF_OVERCOME_SANYO_OFFSET_BUG
                                /* Some Sanyo models (e.g. VPC-C5, C40) suffer from a bug when
                                 * writing the offset for the MNOTE_OLYMPUS_TAG_THUMBNAILIMAGE
                                 * tag in its MakerNote. The offset is actually the absolute
                                 * position in the file instead of the position within the IFD.
                                 */
                            if (dataofs > (buf_size - s) && n->version == sanyoV1) {
                                        /* fix pointer */
                                        dataofs -= datao + 6;
                                        exif_log (en->log, EXIF_LOG_CODE_DEBUG,
                                                  "ExifMnoteOlympus",
                                                  "Inconsistent thumbnail tag offset; attempting to recover");
                            }
#endif
                        }
                        if (CHECKOVERFLOW(dataofs, buf_size, s)) {
                                exif_log (en->log, EXIF_LOG_CODE_DEBUG,
                                          "ExifMnoteOlympus",
                                          "Tag data past end of buffer (%u > %u)",
                                          (unsigned)(dataofs + s), buf_size);
                                continue;
                        }
 
                        n->entries[tcount].data = exif_mem_alloc (en->mem, s);
                        if (!n->entries[tcount].data) {
                                EXIF_LOG_NO_MEMORY(en->log, "ExifMnoteOlympus", s);
                                continue;
                        }
                        memcpy (n->entries[tcount].data, buf + dataofs, s);
                }
 
                /* Tag was successfully parsed */
                ++tcount;
        }
        /* Store the count of successfully parsed tags */
        n->count = tcount;
}
 
static unsigned int
exif_mnote_data_olympus_count (ExifMnoteData *n)
{
        return n ? ((ExifMnoteDataOlympus *) n)->count : 0;
}
 
static unsigned int
exif_mnote_data_olympus_get_id (ExifMnoteData *d, unsigned int n)
{
        ExifMnoteDataOlympus *note = (ExifMnoteDataOlympus *) d;
 
        if (!note) return 0;
        if (note->count <= n) return 0;
        return note->entries[n].tag;
}
 
static const char *
exif_mnote_data_olympus_get_name (ExifMnoteData *d, unsigned int i)
{
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
 
        if (!n) return NULL;
        if (i >= n->count) return NULL;
        return mnote_olympus_tag_get_name (n->entries[i].tag);
}
 
static const char *
exif_mnote_data_olympus_get_title (ExifMnoteData *d, unsigned int i)
{
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
        
        if (!n) return NULL;
        if (i >= n->count) return NULL;
        return mnote_olympus_tag_get_title (n->entries[i].tag);
}
 
static const char *
exif_mnote_data_olympus_get_description (ExifMnoteData *d, unsigned int i)
{
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
        
        if (!n) return NULL;
        if (i >= n->count) return NULL;
        return mnote_olympus_tag_get_description (n->entries[i].tag);
}
 
static void
exif_mnote_data_olympus_set_byte_order (ExifMnoteData *d, ExifByteOrder o)
{
        ExifByteOrder o_orig;
        ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
        unsigned int i;
 
        if (!n) return;
 
        o_orig = n->order;
        n->order = o;
        for (i = 0; i < n->count; i++) {
                if (n->entries[i].components && (n->entries[i].size/n->entries[i].components < exif_format_get_size (n->entries[i].format)))
                        continue;
                n->entries[i].order = o;
                exif_array_set_byte_order (n->entries[i].format, n->entries[i].data,
                                n->entries[i].components, o_orig, o);
        }
}
 
static void
exif_mnote_data_olympus_set_offset (ExifMnoteData *n, unsigned int o)
{
        if (n) ((ExifMnoteDataOlympus *) n)->offset = o;
}
 
static enum OlympusVersion
exif_mnote_data_olympus_identify_variant (const unsigned char *buf,
                unsigned int buf_size)
{
        /* Olympus, Nikon, Sanyo, Epson */
        if (buf_size >= 8) {
                /* Match the terminating NUL character, too */
                if (!memcmp (buf, "OLYMPUS", 8))
                           return olympusV2;
                else if (!memcmp (buf, "OLYMP", 6))
                           return olympusV1;
                else if (!memcmp (buf, "SANYO", 6))
                           return sanyoV1;
                else if (!memcmp (buf, "EPSON", 6))
                           return epsonV1;
                else if (!memcmp (buf, "Nikon", 6)) {
                        switch (buf[6]) {
                                case 1:  return nikonV1;
                                case 2:  return nikonV2;
                                default: return 0; /* Unrecognized Nikon variant */
                        }
                }
        }
 
        /* Another variant of Nikon */
        if ((buf_size >= 2) && (buf[0] == 0x00) && (buf[1] == 0x1b)) {
                return nikonV0;
        }
 
        return unrecognized;
}
 
int
exif_mnote_data_olympus_identify (const ExifData *ed, const ExifEntry *e)
{
        int variant = exif_mnote_data_olympus_identify_variant(e->data, e->size);
 
        if (variant == nikonV0) {
                /* This variant needs some extra checking with the Make */
                char value[5];
                ExifEntry *em = exif_data_get_entry (ed, EXIF_TAG_MAKE);
                variant = unrecognized;
 
                if (em) {
                        const char *v = exif_entry_get_value (em, value, sizeof(value));
                        if (v && (!strncmp (v, "Nikon", sizeof(value)) || 
                                          !strncmp (v, "NIKON", sizeof(value)) ))
                                /* When saved, this variant will be written out like the
                                 * alternative nikonV2 form above instead
                                 */
                                variant = nikonV0;
                }
        }
 
        return variant;
}
 
 
ExifMnoteData *
exif_mnote_data_olympus_new (ExifMem *mem)
{
        ExifMnoteData *d;
 
        if (!mem) return NULL;
        
        d = exif_mem_alloc (mem, sizeof (ExifMnoteDataOlympus));
        if (!d) return NULL;
 
        exif_mnote_data_construct (d, mem);
 
        /* Set up function pointers */
        d->methods.free            = exif_mnote_data_olympus_free;
        d->methods.set_byte_order  = exif_mnote_data_olympus_set_byte_order;
        d->methods.set_offset      = exif_mnote_data_olympus_set_offset;
        d->methods.load            = exif_mnote_data_olympus_load;
        d->methods.save            = exif_mnote_data_olympus_save;
        d->methods.count           = exif_mnote_data_olympus_count;
        d->methods.get_id          = exif_mnote_data_olympus_get_id;
        d->methods.get_name        = exif_mnote_data_olympus_get_name;
        d->methods.get_title       = exif_mnote_data_olympus_get_title;
        d->methods.get_description = exif_mnote_data_olympus_get_description;
        d->methods.get_value       = exif_mnote_data_olympus_get_value;
 
        return d;
}