// ==========================================================
// Metadata functions implementation
// Exif metadata model
//
// Design and implementation by
// - Herv� Drolon (drolon@infonie.fr)
// - Mihail Naydenov (mnaydenov@users.sourceforge.net)
//
// Based on the following implementations:
// - metadata-extractor : http://www.drewnoakes.com/code/exif/
// - jhead : http://www.sentex.net/~mwandel/jhead/
// - ImageMagick : http://www.imagemagick.org/
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================
#ifdef _MSC_VER
#pragma warning (disable : 4786) // identifier was truncated to 'number' characters
#endif
#include "FreeImage.h"
#include "Utilities.h"
#include "FreeImageTag.h"
// ==========================================================
// Exif JPEG routines
// ==========================================================
#define EXIF_NUM_FORMATS 12
#define TAG_EXIF_OFFSET 0x8769 // Exif IFD Pointer
#define TAG_GPS_OFFSET 0x8825 // GPS Info IFD Pointer
#define TAG_INTEROP_OFFSET 0xA005 // Interoperability IFD Pointer
#define TAG_MAKER_NOTE 0x927C // Maker note
// CANON cameras have some funny bespoke fields that need further processing...
#define TAG_CANON_CAMERA_STATE_0x01 0x0001 // tags under tag 0x001 (CameraSettings)
#define TAG_CANON_CAMERA_STATE_0x02 0x0002 // tags under tag 0x002 (FocalLength)
#define TAG_CANON_CAMERA_STATE_0x04 0x0004 // tags under tag 0x004 (ShotInfo)
#define TAG_CANON_CAMERA_STATE_0x12 0x0012 // tags under tag 0x012 (AFInfo)
#define TAG_CANON_CAMERA_STATE_0xA0 0x00A0 // tags under tag 0x0A0 (ProcessingInfo)
#define TAG_CANON_CAMERA_STATE_0xE0 0x00E0 // tags under tag 0x0E0 (SensorInfo)
// =====================================================================
// Reimplementation of strnicmp (it is not supported on some systems)
// =====================================================================
/**
Compare characters of two strings without regard to case.
@param s1 Null-terminated string to compare.
@param s2 Null-terminated string to compare.
@param len Number of characters to compare
@return Returns 0 if s1 substring identical to s2 substring
*/
static int
FreeImage_strnicmp(const char *s1, const char *s2, size_t len) {
unsigned char c1, c2;
if(!s1 || !s2) return -1;
c1 = 0; c2 = 0;
if(len) {
do {
c1 = *s1; c2 = *s2;
s1++; s2++;
if (!c1)
break;
if (!c2)
break;
if (c1 == c2)
continue;
c1 = (BYTE)tolower(c1);
c2 = (BYTE)tolower(c2);
if (c1 != c2)
break;
} while (--len);
}
return (int)c1 - (int)c2;
}
// ----------------------------------------------------------
// Little Endian / Big Endian io routines
// ----------------------------------------------------------
static short
ReadInt16(BOOL msb_order, const void *buffer) {
short value;
if(msb_order) {
value = (short)((((BYTE*) buffer)[0] << 8) | ((BYTE*) buffer)[1]);
return value;
}
value = (short)((((BYTE*) buffer)[1] << 8) | ((BYTE*) buffer)[0]);
return value;
}
static LONG
ReadInt32(BOOL msb_order, const void *buffer) {
LONG value;
if(msb_order) {
value = (LONG)((((BYTE*) buffer)[0] << 24) | (((BYTE*) buffer)[1] << 16) | (((BYTE*) buffer)[2] << 8) | (((BYTE*) buffer)[3]));
return value;
}
value = (LONG)((((BYTE*) buffer)[3] << 24) | (((BYTE*) buffer)[2] << 16) | (((BYTE*) buffer)[1] << 8 ) | (((BYTE*) buffer)[0]));
return value;
}
static unsigned short
ReadUint16(BOOL msb_order, const void *buffer) {
unsigned short value;
if(msb_order) {
value = (unsigned short) ((((BYTE*) buffer)[0] << 8) | ((BYTE*) buffer)[1]);
return value;
}
value = (unsigned short) ((((BYTE*) buffer)[1] << 8) | ((BYTE*) buffer)[0]);
return value;
}
static DWORD
ReadUint32(BOOL msb_order, const void *buffer) {
return ((DWORD) ReadInt32(msb_order, buffer) & 0xFFFFFFFF);
}
// ----------------------------------------------------------
// Exif JPEG markers routines
// ----------------------------------------------------------
/**
Process a IFD offset
Returns the offset and the metadata model for this tag
*/
static void
processIFDOffset(FITAG *tag, char *pval, BOOL msb_order, DWORD *subdirOffset, TagLib::MDMODEL *md_model) {
// get the IFD offset
*subdirOffset = (DWORD) ReadUint32(msb_order, pval);
// select a tag info table
switch(FreeImage_GetTagID(tag)) {
case TAG_EXIF_OFFSET:
*md_model = TagLib::EXIF_EXIF;
break;
case TAG_GPS_OFFSET:
*md_model = TagLib::EXIF_GPS;
break;
case TAG_INTEROP_OFFSET:
*md_model = TagLib::EXIF_INTEROP;
break;
}
}
/**
Process a maker note IFD offset
Returns the offset and the metadata model for this tag
*/
static void
processMakerNote(FIBITMAP *dib, char *pval, BOOL msb_order, DWORD *subdirOffset, TagLib::MDMODEL *md_model) {
FITAG *tagMake = NULL;
*subdirOffset = 0;
*md_model = TagLib::UNKNOWN;
// Determine the camera model and makernote format
// WARNING: note that Maker may be NULL sometimes so check its value before using it
// (NULL pointer checking is done by FreeImage_strnicmp)
FreeImage_GetMetadata(FIMD_EXIF_MAIN, dib, "Make", &tagMake);
const char *Maker = (char*)FreeImage_GetTagValue(tagMake);
if((memcmp("OLYMP\x00\x01", pval, 7) == 0) || (memcmp("OLYMP\x00\x02", pval, 7) == 0) || (memcmp("EPSON", pval, 5) == 0) || (memcmp("AGFA", pval, 4) == 0)) {
// Olympus Type 1 Makernote
// Epson and Agfa use Olympus maker note standard,
// see: http://www.ozhiker.com/electronics/pjmt/jpeg_info/
*md_model = TagLib::EXIF_MAKERNOTE_OLYMPUSTYPE1;
*subdirOffset = 8;
}
else if(memcmp("OLYMPUS\x00\x49\x49\x03\x00", pval, 12) == 0) {
// Olympus Type 2 Makernote
// !!! NOT YET SUPPORTED !!!
*subdirOffset = 0;
*md_model = TagLib::UNKNOWN;
}
else if(memcmp("Nikon", pval, 5) == 0) {
/* There are two scenarios here:
* Type 1:
* :0000: 4E 69 6B 6F 6E 00 01 00-05 00 02 00 02 00 06 00 Nikon...........
* :0010: 00 00 EC 02 00 00 03 00-03 00 01 00 00 00 06 00 ................
* Type 3:
* :0000: 4E 69 6B 6F 6E 00 02 00-00 00 4D 4D 00 2A 00 00 Nikon....MM.*...
* :0010: 00 08 00 1E 00 01 00 07-00 00 00 04 30 32 30 30 ............0200
*/
if (pval[6] == 1) {
// Nikon type 1 Makernote
*md_model = TagLib::EXIF_MAKERNOTE_NIKONTYPE1;
*subdirOffset = 8;
} else if (pval[6] == 2) {
// Nikon type 3 Makernote
*md_model = TagLib::EXIF_MAKERNOTE_NIKONTYPE3;
*subdirOffset = 18;
} else {
// Unsupported makernote data ignored
*subdirOffset = 0;
*md_model = TagLib::UNKNOWN;
}
} else if(Maker && (FreeImage_strnicmp("NIKON", Maker, 5) == 0)) {
// Nikon type 2 Makernote
*md_model = TagLib::EXIF_MAKERNOTE_NIKONTYPE2;
*subdirOffset = 0;
} else if(Maker && (FreeImage_strnicmp("Canon", Maker, 5) == 0)) {
// Canon Makernote
*md_model = TagLib::EXIF_MAKERNOTE_CANON;
*subdirOffset = 0;
} else if(Maker && (FreeImage_strnicmp("Casio", Maker, 5) == 0)) {
// Casio Makernote
if(memcmp("QVC\x00\x00\x00", pval, 6) == 0) {
// Casio Type 2 Makernote
*md_model = TagLib::EXIF_MAKERNOTE_CASIOTYPE2;
*subdirOffset = 6;
} else {
// Casio Type 1 Makernote
*md_model = TagLib::EXIF_MAKERNOTE_CASIOTYPE1;
*subdirOffset = 0;
}
} else if ((memcmp("FUJIFILM", pval, 8) == 0) || (Maker && (FreeImage_strnicmp("Fujifilm", Maker, 8) == 0))) {
// Fujifile Makernote
// Fujifilm's Makernote always use Intel order altough the Exif section maybe in Intel order or in Motorola order.
// If msb_order == TRUE, the Makernote won't be read:
// the value of ifdStart will be 0x0c000000 instead of 0x0000000c and the MakerNote section will be discarded later
// in jpeg_read_exif_dir because the IFD is too high
*md_model = TagLib::EXIF_MAKERNOTE_FUJIFILM;
DWORD ifdStart = (DWORD) ReadUint32(msb_order, pval + 8);
*subdirOffset = ifdStart;
}
else if(memcmp("KYOCERA\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x00\x00\x00", pval, 22) == 0) {
*md_model = TagLib::EXIF_MAKERNOTE_KYOCERA;
*subdirOffset = 22;
}
else if(Maker && (FreeImage_strnicmp("Minolta", Maker, 7) == 0)) {
// Minolta maker note
*md_model = TagLib::EXIF_MAKERNOTE_MINOLTA;
*subdirOffset = 0;
}
else if(memcmp("Panasonic\x00\x00\x00", pval, 12) == 0) {
// Panasonic maker note
*md_model = TagLib::EXIF_MAKERNOTE_PANASONIC;
*subdirOffset = 12;
}
else if(Maker && (FreeImage_strnicmp("LEICA", Maker, 5) == 0)) {
// Leica maker note
if(memcmp("LEICA\x00\x00\x00", pval, 8) == 0) {
// not yet supported makernote data ignored
*subdirOffset = 0;
*md_model = TagLib::UNKNOWN;
}
}
else if(Maker && ((FreeImage_strnicmp("Pentax", Maker, 6) == 0) || (FreeImage_strnicmp("Asahi", Maker, 5) == 0))) {
// Pentax maker note
if(memcmp("AOC\x00", pval, 4) == 0) {
// Type 2 Pentax Makernote
*md_model = TagLib::EXIF_MAKERNOTE_PENTAX;
*subdirOffset = 6;
} else {
// Type 1 Pentax Makernote
*md_model = TagLib::EXIF_MAKERNOTE_ASAHI;
*subdirOffset = 0;
}
}
else if((memcmp("SONY CAM\x20\x00\x00\x00", pval, 12) == 0) || (memcmp("SONY DSC\x20\x00\x00\x00", pval, 12) == 0)) {
*md_model = TagLib::EXIF_MAKERNOTE_SONY;
*subdirOffset = 12;
}
else if((memcmp("SIGMA\x00\x00\x00", pval, 8) == 0) || (memcmp("FOVEON\x00\x00", pval, 8) == 0)) {
FITAG *tagModel = NULL;
FreeImage_GetMetadata(FIMD_EXIF_MAIN, dib, "Model", &tagModel);
const char *Model = (char*)FreeImage_GetTagValue(tagModel);
if(Model && (memcmp("SIGMA SD1\x00", Model, 10) == 0)) {
// Sigma SD1 maker note
*subdirOffset = 10;
*md_model = TagLib::EXIF_MAKERNOTE_SIGMA_SD1;
} else {
// Sigma / Foveon makernote
*subdirOffset = 10;
*md_model = TagLib::EXIF_MAKERNOTE_SIGMA_FOVEON;
}
}
}
/**
Process a Canon maker note tag.
A single Canon tag may contain many other tags within.
*/
static BOOL
processCanonMakerNoteTag(FIBITMAP *dib, FITAG *tag) {
char defaultKey[16];
DWORD startIndex = 0;
TagLib& s = TagLib::instance();
WORD tag_id = FreeImage_GetTagID(tag);
int subTagTypeBase = 0;
switch(tag_id) {
case TAG_CANON_CAMERA_STATE_0x01:
subTagTypeBase = 0xC100;
startIndex = 1;
break;
case TAG_CANON_CAMERA_STATE_0x02:
subTagTypeBase = 0xC200;
startIndex = 0;
break;
case TAG_CANON_CAMERA_STATE_0x04:
subTagTypeBase = 0xC400;
startIndex = 1;
break;
case TAG_CANON_CAMERA_STATE_0x12:
subTagTypeBase = 0x1200;
startIndex = 0;
break;
case TAG_CANON_CAMERA_STATE_0xA0:
subTagTypeBase = 0xCA00;
startIndex = 1;
break;
case TAG_CANON_CAMERA_STATE_0xE0:
subTagTypeBase = 0xCE00;
startIndex = 1;
break;
default:
{
// process as a normal tag
// get the tag key and description
const char *key = s.getTagFieldName(TagLib::EXIF_MAKERNOTE_CANON, tag_id, defaultKey);
FreeImage_SetTagKey(tag, key);
const char *description = s.getTagDescription(TagLib::EXIF_MAKERNOTE_CANON, tag_id);
FreeImage_SetTagDescription(tag, description);
// store the tag
if(key) {
FreeImage_SetMetadata(FIMD_EXIF_MAKERNOTE, dib, key, tag);
}
return TRUE;
}
break;
}
WORD *pvalue = (WORD*)FreeImage_GetTagValue(tag);
// create a tag
FITAG *canonTag = FreeImage_CreateTag();
if(!canonTag) return FALSE;
// we intentionally skip the first array member (if needed)
for (DWORD i = startIndex; i < FreeImage_GetTagCount(tag); i++) {
tag_id = (WORD)(subTagTypeBase + i);
FreeImage_SetTagID(canonTag, tag_id);
FreeImage_SetTagType(canonTag, FIDT_SHORT);
FreeImage_SetTagCount(canonTag, 1);
FreeImage_SetTagLength(canonTag, 2);
FreeImage_SetTagValue(canonTag, &pvalue[i]);
// get the tag key and description
const char *key = s.getTagFieldName(TagLib::EXIF_MAKERNOTE_CANON, tag_id, defaultKey);
FreeImage_SetTagKey(canonTag, key);
const char *description = s.getTagDescription(TagLib::EXIF_MAKERNOTE_CANON, tag_id);
FreeImage_SetTagDescription(canonTag, description);
// store the tag
if(key) {
FreeImage_SetMetadata(FIMD_EXIF_MAKERNOTE, dib, key, canonTag);
}
}
// delete the tag
FreeImage_DeleteTag(canonTag);
return TRUE;
}
/**
Process a standard Exif tag
*/
static void
processExifTag(FIBITMAP *dib, FITAG *tag, char *pval, BOOL msb_order, TagLib::MDMODEL md_model) {
char defaultKey[16];
int n;
DWORD i;
// allocate a buffer to store the tag value
BYTE *exif_value = (BYTE*)malloc(FreeImage_GetTagLength(tag) * sizeof(BYTE));
if(NULL == exif_value) {
// out of memory ...
return;
}
memset(exif_value, 0, FreeImage_GetTagLength(tag) * sizeof(BYTE));
// get the tag value
switch(FreeImage_GetTagType(tag)) {
case FIDT_SHORT:
{
WORD *value = (WORD*)&exif_value[0];
for(i = 0; i < FreeImage_GetTagCount(tag); i++) {
value[i] = ReadUint16(msb_order, pval + i * sizeof(WORD));
}
FreeImage_SetTagValue(tag, value);
break;
}
case FIDT_SSHORT:
{
short *value = (short*)&exif_value[0];
for(i = 0; i < FreeImage_GetTagCount(tag); i++) {
value[i] = ReadInt16(msb_order, pval + i * sizeof(short));
}
FreeImage_SetTagValue(tag, value);
break;
}
case FIDT_LONG:
{
DWORD *value = (DWORD*)&exif_value[0];
for(i = 0; i < FreeImage_GetTagCount(tag); i++) {
value[i] = ReadUint32(msb_order, pval + i * sizeof(DWORD));
}
FreeImage_SetTagValue(tag, value);
break;
}
case FIDT_SLONG:
{
LONG *value = (LONG*)&exif_value[0];
for(i = 0; i < FreeImage_GetTagCount(tag); i++) {
value[i] = ReadInt32(msb_order, pval + i * sizeof(LONG));
}
FreeImage_SetTagValue(tag, value);
break;
}
case FIDT_RATIONAL:
{
n = sizeof(DWORD);
DWORD *value = (DWORD*)&exif_value[0];
for(i = 0; i < 2 * FreeImage_GetTagCount(tag); i++) {
// read a sequence of (numerator, denominator)
value[i] = ReadUint32(msb_order, n*i + (char*)pval);
}
FreeImage_SetTagValue(tag, value);
break;
}
case FIDT_SRATIONAL:
{
n = sizeof(LONG);
LONG *value = (LONG*)&exif_value[0];
for(i = 0; i < 2 * FreeImage_GetTagCount(tag); i++) {
// read a sequence of (numerator, denominator)
value[i] = ReadInt32(msb_order, n*i + (char*)pval);
}
FreeImage_SetTagValue(tag, value);
break;
}
case FIDT_BYTE:
case FIDT_ASCII:
case FIDT_SBYTE:
case FIDT_UNDEFINED:
case FIDT_FLOAT:
case FIDT_DOUBLE:
default:
FreeImage_SetTagValue(tag, pval);
break;
}
if(md_model == TagLib::EXIF_MAKERNOTE_CANON) {
// A single Canon tag can have multiple values within
processCanonMakerNoteTag(dib, tag);
}
else {
TagLib& s = TagLib::instance();
WORD tag_id = FreeImage_GetTagID(tag);
// get the tag key and description
const char *key = s.getTagFieldName(md_model, tag_id, defaultKey);
FreeImage_SetTagKey(tag, key);
const char *description = s.getTagDescription(md_model, tag_id);
FreeImage_SetTagDescription(tag, description);
// store the tag
if(key) {
FreeImage_SetMetadata(s.getFreeImageModel(md_model), dib, key, tag);
}
}
// free the temporary buffer
free(exif_value);
}
/**
Process Exif directory
@param dib Input FIBITMAP
@param tiffp Pointer to the TIFF header
@param offset 0th IFD offset
@param length Length of the datafile
@param msb_order Endianess order of the datafile
@return
*/
static BOOL
jpeg_read_exif_dir(FIBITMAP *dib, const BYTE *tiffp, unsigned long offset, unsigned int length, BOOL msb_order) {
WORD de, nde;
std::stack<WORD> destack; // directory entries stack
std::stack<const BYTE*> ifdstack; // IFD stack
std::stack<TagLib::MDMODEL> modelstack; // metadata model stack
// Keep a list of already visited IFD to avoid stack overflows
// when recursive/cyclic directory structures exist.
// This kind of recursive Exif file was encountered with Kodak images coming from
// KODAK PROFESSIONAL DCS Photo Desk JPEG Export v3.2 W
std::map<DWORD, int> visitedIFD;
/*
"An Image File Directory (IFD) consists of a 2-byte count of the number of directory
entries (i.e. the number of fields), followed by a sequence of 12-byte field
entries, followed by a 4-byte offset of the next IFD (or 0 if none)."
The "next IFD" (1st IFD) is the thumbnail.
*/
#define DIR_ENTRY_ADDR(_start, _entry) (_start + 2 + (12 * _entry))
// set the metadata model to Exif
TagLib::MDMODEL md_model = TagLib::EXIF_MAIN;
// set the pointer to the first IFD (0th IFD) and follow it were it leads.
const BYTE *ifd0th = (BYTE*)tiffp + offset;
const BYTE *ifdp = ifd0th;
de = 0;
do {
// if there is anything on the stack then pop it off
if(!destack.empty()) {
ifdp = ifdstack.top(); ifdstack.pop();
de = destack.top(); destack.pop();
md_model = modelstack.top(); modelstack.pop();
}
// remember that we've visited this directory and entry so that we don't visit it again later
DWORD visited = (DWORD)( (((size_t)ifdp & 0xFFFF) << 16) | (size_t)de );
if(visitedIFD.find(visited) != visitedIFD.end()) {
continue;
} else {
visitedIFD[visited] = 1; // processed
}
// determine how many entries there are in the current IFD
nde = ReadUint16(msb_order, ifdp);
for(; de < nde; de++) {
char *pde = NULL; // pointer to the directory entry
char *pval = NULL; // pointer to the tag value
// create a tag
FITAG *tag = FreeImage_CreateTag();
if(!tag) return FALSE;
// point to the directory entry
pde = (char*) DIR_ENTRY_ADDR(ifdp, de);
// get the tag ID
FreeImage_SetTagID(tag, ReadUint16(msb_order, pde));
// get the tag type
WORD tag_type = (WORD)ReadUint16(msb_order, pde + 2);
if((tag_type - 1) >= EXIF_NUM_FORMATS) {
// a problem occured : delete the tag (not free'd after)
FreeImage_DeleteTag(tag);
// break out of the for loop
break;
}
FreeImage_SetTagType(tag, (FREE_IMAGE_MDTYPE)tag_type);
// get number of components
FreeImage_SetTagCount(tag, ReadUint32(msb_order, pde + 4));
// check that tag length (size of the tag value in bytes) will fit in a DWORD
unsigned tag_data_width = FreeImage_TagDataWidth(FreeImage_GetTagType(tag));
if (tag_data_width != 0 && FreeImage_GetTagCount(tag) > ~(DWORD)0 / tag_data_width) {
FreeImage_DeleteTag(tag);
// jump to next entry
continue;
}
FreeImage_SetTagLength(tag, FreeImage_GetTagCount(tag) * tag_data_width);
if(FreeImage_GetTagLength(tag) <= 4) {
// 4 bytes or less and value is in the dir entry itself
pval = pde + 8;
} else {
// if its bigger than 4 bytes, the directory entry contains an offset
// first check if offset exceeds buffer, at this stage FreeImage_GetTagLength may return invalid data
DWORD offset_value = ReadUint32(msb_order, pde + 8);
if(offset_value > length) {
// a problem occured : delete the tag (not free'd after)
FreeImage_DeleteTag(tag);
// jump to next entry
continue;
}
// now check that length does not exceed the buffer size
if(FreeImage_GetTagLength(tag) > length - offset_value){
// a problem occured : delete the tag (not free'd after)
FreeImage_DeleteTag(tag);
// jump to next entry
continue;
}
pval = (char*)(tiffp + offset_value);
}
// check for a IFD offset
BOOL isIFDOffset = FALSE;
switch(FreeImage_GetTagID(tag)) {
case TAG_EXIF_OFFSET:
case TAG_GPS_OFFSET:
case TAG_INTEROP_OFFSET:
case TAG_MAKER_NOTE:
isIFDOffset = TRUE;
break;
}
if(isIFDOffset) {
DWORD sub_offset = 0;
TagLib::MDMODEL next_mdmodel = md_model;
const BYTE *next_ifd = ifdp;
// get offset and metadata model
if (FreeImage_GetTagID(tag) == TAG_MAKER_NOTE) {
processMakerNote(dib, pval, msb_order, &sub_offset, &next_mdmodel);
next_ifd = (BYTE*)pval + sub_offset;
} else {
processIFDOffset(tag, pval, msb_order, &sub_offset, &next_mdmodel);
next_ifd = (BYTE*)tiffp + sub_offset;
}
if((sub_offset < (DWORD) length) && (next_mdmodel != TagLib::UNKNOWN)) {
// push our current directory state onto the stack
ifdstack.push(ifdp);
// bump to the next entry
de++;
destack.push(de);
// push our current metadata model
modelstack.push(md_model);
// push new state onto of stack to cause a jump
ifdstack.push(next_ifd);
destack.push(0);
// select a new metadata model
modelstack.push(next_mdmodel);
// delete the tag as it won't be stored nor deleted in the for() loop
FreeImage_DeleteTag(tag);
break; // break out of the for loop
}
else {
// unsupported camera model, canon maker tag or something unknown
// process as a standard tag
processExifTag(dib, tag, pval, msb_order, md_model);
}
} else {
// process as a standard tag
processExifTag(dib, tag, pval, msb_order, md_model);
}
// delete the tag
FreeImage_DeleteTag(tag);
} // for(nde)
// additional thumbnail data is skipped
} while (!destack.empty());
//
// --- handle thumbnail data ---
//
const WORD entriesCount0th = ReadUint16(msb_order, ifd0th);
DWORD next_offset = ReadUint32(msb_order, DIR_ENTRY_ADDR(ifd0th, entriesCount0th));
if((next_offset == 0) || (next_offset >= length)) {
return TRUE; //< no thumbnail
}
const BYTE* const ifd1st = (BYTE*)tiffp + next_offset;
const WORD entriesCount1st = ReadUint16(msb_order, ifd1st);
unsigned thCompression = 0;
unsigned thOffset = 0;
unsigned thSize = 0;
for(int e = 0; e < entriesCount1st; e++) {
// point to the directory entry
const BYTE* base = DIR_ENTRY_ADDR(ifd1st, e);
// check for buffer overflow
const size_t remaining = (size_t)base + 12 - (size_t)tiffp;
if(remaining >= length) {
// bad IFD1 directory, ignore it
return FALSE;
}
// get the tag ID
WORD tag = ReadUint16(msb_order, base);
// get the tag type
WORD type = ReadUint16(msb_order, base + sizeof(WORD));
// get number of components
DWORD count = ReadUint32(msb_order, base + sizeof(WORD) + sizeof(WORD));
// get the tag value
DWORD offset = ReadUint32(msb_order, base + sizeof(WORD) + sizeof(WORD) + sizeof(DWORD));
switch(tag) {
case TAG_COMPRESSION:
// Tiff Compression Tag (should be COMPRESSION_OJPEG (6), but is not always respected)
thCompression = offset;
break;
case TAG_JPEG_INTERCHANGE_FORMAT:
// Tiff JPEGInterchangeFormat Tag
thOffset = offset;
break;
case TAG_JPEG_INTERCHANGE_FORMAT_LENGTH:
// Tiff JPEGInterchangeFormatLength Tag
thSize = offset;
break;
// ### X and Y Resolution ignored, orientation ignored
case TAG_X_RESOLUTION: // XResolution
case TAG_Y_RESOLUTION: // YResolution
case TAG_RESOLUTION_UNIT: // ResolutionUnit
case TAG_ORIENTATION: // Orientation
break;
default:
break;
}
}
if(/*thCompression != 6 ||*/ thOffset == 0 || thSize == 0) {
return TRUE;
}
if(thOffset + thSize > length) {
return TRUE;
}
// load the thumbnail
const BYTE *thLocation = tiffp + thOffset;
FIMEMORY* hmem = FreeImage_OpenMemory(const_cast<BYTE*>(thLocation), thSize);
FIBITMAP* thumbnail = FreeImage_LoadFromMemory(FIF_JPEG, hmem);
FreeImage_CloseMemory(hmem);
// store the thumbnail
FreeImage_SetThumbnail(dib, thumbnail);
// then delete it
FreeImage_Unload(thumbnail);
return TRUE;
}
/**
Read and decode JPEG_APP1 marker (Exif profile)
@param dib Input FIBITMAP
@param dataptr Pointer to the APP1 marker
@param datalen APP1 marker length
@return Returns TRUE if successful, FALSE otherwise
*/
BOOL
jpeg_read_exif_profile(FIBITMAP *dib, const BYTE *dataptr, unsigned int datalen) {
// marker identifying string for Exif = "Exif\0\0"
BYTE exif_signature[6] = { 0x45, 0x78, 0x69, 0x66, 0x00, 0x00 };
BYTE lsb_first[4] = { 0x49, 0x49, 0x2A, 0x00 }; // Intel order
BYTE msb_first[4] = { 0x4D, 0x4D, 0x00, 0x2A }; // Motorola order
unsigned int length = datalen;
BYTE *profile = (BYTE*)dataptr;
// verify the identifying string
if(memcmp(exif_signature, profile, sizeof(exif_signature)) == 0) {
// Exif profile - TIFF header with 2 IFDs. 0th - the image attributes, 1st - may be used for thumbnail
profile += sizeof(exif_signature);
length -= sizeof(exif_signature);
// read the TIFF header (8 bytes)
// check the endianess order
BOOL bMotorolaOrder = TRUE;
if(memcmp(profile, lsb_first, sizeof(lsb_first)) == 0) {
// Exif section in Intel order
bMotorolaOrder = FALSE;
} else {
if(memcmp(profile, msb_first, sizeof(msb_first)) == 0) {
// Exif section in Motorola order
bMotorolaOrder = TRUE;
} else {
// Invalid Exif alignment marker
return FALSE;
}
}
// this is the offset to the first IFD (Image File Directory)
unsigned long first_offset = ReadUint32(bMotorolaOrder, profile + 4);
if (first_offset > length) {
// bad Exif data
return FALSE;
}
/*
Note: as FreeImage 3.14.0, this test is no longer needed for images with similar suspicious offset
=> tested with Pentax Optio 230, FujiFilm SP-2500 and Canon EOS 300D
if (first_offset < 8 || first_offset > 16) {
// This is usually set to 8
// but PENTAX Optio 230 has it set differently, and uses it as offset.
FreeImage_OutputMessageProc(FIF_JPEG, "Exif: Suspicious offset of first IFD value");
return FALSE;
}
*/
// process Exif directories
return jpeg_read_exif_dir(dib, profile, first_offset, length, bMotorolaOrder);
}
return FALSE;
}