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tdegraphics/kfile-plugins/jpeg/exif.cpp

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//--------------------------------------------------------------------------
// Program to pull the information out of various types of EFIF digital
// camera files and show it in a reasonably consistent way
//
// This module parses the very complicated exif structures.
//
// Matthias Wandel, Dec 1999 - August 2000
//--------------------------------------------------------------------------
#include "exif.h"
#include <tqwmatrix.h>
#include <kglobal.h>
static unsigned char * LastExifRefd;
static int ExifSettingsLength;
static double FocalplaneXRes;
static double FocalplaneUnits;
static int MotorolaOrder = 0;
static int SectionsRead;
//static int HaveAll;
//--------------------------------------------------------------------------
// Table of Jpeg encoding process names
#define M_SOF0 0xC0 // Start Of Frame N
#define M_SOF1 0xC1 // N indicates which compression process
#define M_SOF2 0xC2 // Only SOF0-SOF2 are now in common use
#define M_SOF3 0xC3
#define M_SOF5 0xC5 // NB: codes C4 and CC are NOT SOF markers
#define M_SOF6 0xC6
#define M_SOF7 0xC7
#define M_SOF9 0xC9
#define M_SOF10 0xCA
#define M_SOF11 0xCB
#define M_SOF13 0xCD
#define M_SOF14 0xCE
#define M_SOF15 0xCF
#define M_SOI 0xD8 // Start Of Image (beginning of datastream)
#define M_EOI 0xD9 // End Of Image (end of datastream)
#define M_SOS 0xDA // Start Of Scan (begins compressed data)
#define M_JFIF 0xE0 // Jfif marker
#define M_EXIF 0xE1 // Exif marker
#define M_COM 0xFE // COMment
TagTable_t ProcessTable[] = {
{ M_SOF0, "Baseline"},
{ M_SOF1, "Extended sequential"},
{ M_SOF2, "Progressive"},
{ M_SOF3, "Lossless"},
{ M_SOF5, "Differential sequential"},
{ M_SOF6, "Differential progressive"},
{ M_SOF7, "Differential lossless"},
{ M_SOF9, "Extended sequential, arithmetic coding"},
{ M_SOF10, "Progressive, arithmetic coding"},
{ M_SOF11, "Lossless, arithmetic coding"},
{ M_SOF13, "Differential sequential, arithmetic coding"},
{ M_SOF14, "Differential progressive, arithmetic coding"},
{ M_SOF15, "Differential lossless, arithmetic coding"},
{ 0, "Unknown"}
};
//--------------------------------------------------------------------------
// Describes format descriptor
static int BytesPerFormat[] = {0,1,1,2,4,8,1,1,2,4,8,4,8};
#define NUM_FORMATS 12
#define FMT_BYTE 1
#define FMT_STRING 2
#define FMT_USHORT 3
#define FMT_ULONG 4
#define FMT_URATIONAL 5
#define FMT_SBYTE 6
#define FMT_UNDEFINED 7
#define FMT_SSHORT 8
#define FMT_SLONG 9
#define FMT_SRATIONAL 10
#define FMT_SINGLE 11
#define FMT_DOUBLE 12
//--------------------------------------------------------------------------
// Describes tag values
#define TAG_EXIF_OFFSET 0x8769
#define TAG_INTEROP_OFFSET 0xa005
#define TAG_MAKE 0x010F
#define TAG_MODEL 0x0110
#define TAG_ORIENTATION 0x0112
#define TAG_EXPOSURETIME 0x829A
#define TAG_FNUMBER 0x829D
#define TAG_SHUTTERSPEED 0x9201
#define TAG_APERTURE 0x9202
#define TAG_MAXAPERTURE 0x9205
#define TAG_FOCALLENGTH 0x920A
#define TAG_DATETIME_ORIGINAL 0x9003
#define TAG_USERCOMMENT 0x9286
#define TAG_SUBJECT_DISTANCE 0x9206
#define TAG_FLASH 0x9209
#define TAG_FOCALPLANEXRES 0xa20E
#define TAG_FOCALPLANEUNITS 0xa210
#define TAG_EXIF_IMAGEWIDTH 0xA002
#define TAG_EXIF_IMAGELENGTH 0xA003
// the following is added 05-jan-2001 vcs
#define TAG_EXPOSURE_BIAS 0x9204
#define TAG_WHITEBALANCE 0x9208
#define TAG_METERING_MODE 0x9207
#define TAG_EXPOSURE_PROGRAM 0x8822
#define TAG_ISO_EQUIVALENT 0x8827
#define TAG_COMPRESSION_LEVEL 0x9102
#define TAG_THUMBNAIL_OFFSET 0x0201
#define TAG_THUMBNAIL_LENGTH 0x0202
/*static TagTable_t TagTable[] = {
{ 0x100, "ImageWidth"},
{ 0x101, "ImageLength"},
{ 0x102, "BitsPerSample"},
{ 0x103, "Compression"},
{ 0x106, "PhotometricInterpretation"},
{ 0x10A, "FillOrder"},
{ 0x10D, "DocumentName"},
{ 0x10E, "ImageDescription"},
{ 0x10F, "Make"},
{ 0x110, "Model"},
{ 0x111, "StripOffsets"},
{ 0x112, "Orientation"},
{ 0x115, "SamplesPerPixel"},
{ 0x116, "RowsPerStrip"},
{ 0x117, "StripByteCounts"},
{ 0x11A, "XResolution"},
{ 0x11B, "YResolution"},
{ 0x11C, "PlanarConfiguration"},
{ 0x128, "ResolutionUnit"},
{ 0x12D, "TransferFunction"},
{ 0x131, "Software"},
{ 0x132, "DateTime"},
{ 0x13B, "Artist"},
{ 0x13E, "WhitePoint"},
{ 0x13F, "PrimaryChromaticities"},
{ 0x156, "TransferRange"},
{ 0x200, "JPEGProc"},
{ 0x201, "ThumbnailOffset"},
{ 0x202, "ThumbnailLength"},
{ 0x211, "YCbCrCoefficients"},
{ 0x212, "YCbCrSubSampling"},
{ 0x213, "YCbCrPositioning"},
{ 0x214, "ReferenceBlackWhite"},
{ 0x828D, "CFARepeatPatternDim"},
{ 0x828E, "CFAPattern"},
{ 0x828F, "BatteryLevel"},
{ 0x8298, "Copyright"},
{ 0x829A, "ExposureTime"},
{ 0x829D, "FNumber"},
{ 0x83BB, "IPTC/NAA"},
{ 0x8769, "ExifOffset"},
{ 0x8773, "InterColorProfile"},
{ 0x8822, "ExposureProgram"},
{ 0x8824, "SpectralSensitivity"},
{ 0x8825, "GPSInfo"},
{ 0x8827, "ISOSpeedRatings"},
{ 0x8828, "OECF"},
{ 0x9000, "ExifVersion"},
{ 0x9003, "DateTimeOriginal"},
{ 0x9004, "DateTimeDigitized"},
{ 0x9101, "ComponentsConfiguration"},
{ 0x9102, "CompressedBitsPerPixel"},
{ 0x9201, "ShutterSpeedValue"},
{ 0x9202, "ApertureValue"},
{ 0x9203, "BrightnessValue"},
{ 0x9204, "ExposureBiasValue"},
{ 0x9205, "MaxApertureValue"},
{ 0x9206, "SubjectDistance"},
{ 0x9207, "MeteringMode"},
{ 0x9208, "LightSource"},
{ 0x9209, "Flash"},
{ 0x920A, "FocalLength"},
{ 0x927C, "MakerNote"},
{ 0x9286, "UserComment"},
{ 0x9290, "SubSecTime"},
{ 0x9291, "SubSecTimeOriginal"},
{ 0x9292, "SubSecTimeDigitized"},
{ 0xA000, "FlashPixVersion"},
{ 0xA001, "ColorSpace"},
{ 0xA002, "ExifImageWidth"},
{ 0xA003, "ExifImageLength"},
{ 0xA005, "InteroperabilityOffset"},
{ 0xA20B, "FlashEnergy"}, // 0x920B in TIFF/EP
{ 0xA20C, "SpatialFrequencyResponse"}, // 0x920C - -
{ 0xA20E, "FocalPlaneXResolution"}, // 0x920E - -
{ 0xA20F, "FocalPlaneYResolution"}, // 0x920F - -
{ 0xA210, "FocalPlaneResolutionUnit"}, // 0x9210 - -
{ 0xA214, "SubjectLocation"}, // 0x9214 - -
{ 0xA215, "ExposureIndex"}, // 0x9215 - -
{ 0xA217, "SensingMethod"}, // 0x9217 - -
{ 0xA300, "FileSource"},
{ 0xA301, "SceneType"},
{ 0, NULL}
} ;
*/
//--------------------------------------------------------------------------
// Parse the marker stream until SOS or EOI is seen;
//--------------------------------------------------------------------------
int ExifData::ReadJpegSections (TQFile & infile, ReadMode_t ReadMode)
{
int a;
a = infile.getch();
if (a != 0xff || infile.getch() != M_SOI) {
SectionsRead = 0;
return false;
}
for(SectionsRead = 0; SectionsRead < MAX_SECTIONS-1; ){
int marker = 0;
int got;
unsigned int ll,lh;
unsigned int itemlen;
uchar * Data;
for (a=0;a<7;a++){
marker = infile.getch();
if (marker != 0xff) break;
if (a >= 6){
kdDebug(7034) << "too many padding bytes\n";
return false;
}
}
if (marker == 0xff){
// 0xff is legal padding, but if we get that many, something's wrong.
throw FatalError("too many padding bytes!");
}
Sections[SectionsRead].Type = marker;
// Read the length of the section.
lh = (uchar) infile.getch();
ll = (uchar) infile.getch();
itemlen = (lh << 8) | ll;
if (itemlen < 2) {
throw FatalError("invalid marker");
}
Sections[SectionsRead].Size = itemlen;
Data = (uchar *)malloc(itemlen+1); // Add 1 to allow sticking a 0 at the end.
Sections[SectionsRead].Data = Data;
// Store first two pre-read bytes.
Data[0] = (uchar)lh;
Data[1] = (uchar)ll;
got = infile.readBlock((char*)Data+2, itemlen-2); // Read the whole section.
if (( unsigned ) got != itemlen-2){
throw FatalError("reading from file");
}
SectionsRead++;
switch(marker){
case M_SOS: // stop before hitting compressed data
// If reading entire image is requested, read the rest of the data.
if (ReadMode & READ_IMAGE){
unsigned long size;
size = kMax( 0ul, (unsigned long)(infile.size()-infile.at()) );
Data = (uchar *)malloc(size);
if (Data == NULL){
throw FatalError("could not allocate data for entire image");
}
got = infile.readBlock((char*)Data, size);
if (( unsigned ) got != size){
throw FatalError("could not read the rest of the image");
}
Sections[SectionsRead].Data = Data;
Sections[SectionsRead].Size = size;
Sections[SectionsRead].Type = PSEUDO_IMAGE_MARKER;
SectionsRead ++;
//HaveAll = 1;
}
return true;
case M_EOI: // in case it's a tables-only JPEG stream
kdDebug(7034) << "No image in jpeg!\n";
return false;
case M_COM: // Comment section
// pieczy 2002-02-12
// now the User comment goes to UserComment
// so we can store a Comment section also in READ_EXIF mode
process_COM(Data, itemlen);
break;
case M_JFIF:
// Regular jpegs always have this tag, exif images have the exif
// marker instead, althogh ACDsee will write images with both markers.
// this program will re-create this marker on absence of exif marker.
// hence no need to keep the copy from the file.
free(Sections[--SectionsRead].Data);
break;
case M_EXIF:
// Seen files from some 'U-lead' software with Vivitar scanner
// that uses marker 31 for non exif stuff. Thus make sure
// it says 'Exif' in the section before treating it as exif.
if ((ReadMode & READ_EXIF) && memcmp(Data+2, "Exif", 4) == 0){
process_EXIF((uchar *)Data, itemlen); // FIXME: This call
// requires Data to be array of at least 8 bytes. Code
// above only checks for itemlen < 2.
}else{
// Discard this section.
free(Sections[--SectionsRead].Data);
}
break;
case M_SOF0:
case M_SOF1:
case M_SOF2:
case M_SOF3:
case M_SOF5:
case M_SOF6:
case M_SOF7:
case M_SOF9:
case M_SOF10:
case M_SOF11:
case M_SOF13:
case M_SOF14:
case M_SOF15:
process_SOFn(Data, marker); //FIXME: This call requires Data to
// be array of at least 8 bytes. Code above only checks for
// itemlen < 2.
break;
default:
break;
}
}
return true;
}
//--------------------------------------------------------------------------
// Discard read data.
//--------------------------------------------------------------------------
void ExifData::DiscardData(void)
{
for (int a=0; a < SectionsRead; a++)
free(Sections[a].Data);
SectionsRead = 0;
}
//--------------------------------------------------------------------------
// Convert a 16 bit unsigned value from file's native byte order
//--------------------------------------------------------------------------
int ExifData::Get16u(void * Short)
{
if (MotorolaOrder){
return (((uchar *)Short)[0] << 8) | ((uchar *)Short)[1];
}else{
return (((uchar *)Short)[1] << 8) | ((uchar *)Short)[0];
}
}
//--------------------------------------------------------------------------
// Convert a 32 bit signed value from file's native byte order
//--------------------------------------------------------------------------
int ExifData::Get32s(void * Long)
{
if (MotorolaOrder){
return ((( char *)Long)[0] << 24) | (((uchar *)Long)[1] << 16)
| (((uchar *)Long)[2] << 8 ) | (((uchar *)Long)[3] << 0 );
}else{
return ((( char *)Long)[3] << 24) | (((uchar *)Long)[2] << 16)
| (((uchar *)Long)[1] << 8 ) | (((uchar *)Long)[0] << 0 );
}
}
//--------------------------------------------------------------------------
// Convert a 32 bit unsigned value from file's native byte order
//--------------------------------------------------------------------------
unsigned ExifData::Get32u(void * Long)
{
return (unsigned)Get32s(Long) & 0xffffffff;
}
//--------------------------------------------------------------------------
// Evaluate number, be it int, rational, or float from directory.
//--------------------------------------------------------------------------
double ExifData::ConvertAnyFormat(void * ValuePtr, int Format)
{
double Value;
Value = 0;
switch(Format){
case FMT_SBYTE: Value = *(signed char *)ValuePtr; break;
case FMT_BYTE: Value = *(uchar *)ValuePtr; break;
case FMT_USHORT: Value = Get16u(ValuePtr); break;
case FMT_ULONG: Value = Get32u(ValuePtr); break;
case FMT_URATIONAL:
case FMT_SRATIONAL:
{
int Num,Den;
Num = Get32s(ValuePtr);
Den = Get32s(4+(char *)ValuePtr);
if (Den == 0){
Value = 0;
}else{
Value = (double)Num/Den;
}
break;
}
case FMT_SSHORT: Value = (signed short)Get16u(ValuePtr); break;
case FMT_SLONG: Value = Get32s(ValuePtr); break;
// Not sure if this is correct (never seen float used in Exif format)
case FMT_SINGLE: Value = (double)*(float *)ValuePtr; break;
case FMT_DOUBLE: Value = *(double *)ValuePtr; break;
}
return Value;
}
//--------------------------------------------------------------------------
// Process one of the nested EXIF directories.
//--------------------------------------------------------------------------
void ExifData::ProcessExifDir(unsigned char * DirStart, unsigned char * OffsetBase, unsigned ExifLength, unsigned NestingLevel)
{
int de;
int a;
int NumDirEntries;
unsigned ThumbnailOffset = 0;
unsigned ThumbnailSize = 0;
if ( NestingLevel > 4)
throw FatalError("Maximum directory nesting exceeded (corrupt exif header)");
NumDirEntries = Get16u(DirStart);
#define DIR_ENTRY_ADDR(Start, Entry) (Start+2+12*(Entry))
{
unsigned char * DirEnd;
DirEnd = DIR_ENTRY_ADDR(DirStart, NumDirEntries);
if (DirEnd+4 > (OffsetBase+ExifLength)){
if (DirEnd+2 == OffsetBase+ExifLength || DirEnd == OffsetBase+ExifLength){
// Version 1.3 of jhead would truncate a bit too much.
// This also caught later on as well.
}else{
// Note: Files that had thumbnails trimmed with jhead 1.3 or earlier
// might trigger this.
throw FatalError("Illegally sized directory");
}
}
if (DirEnd < LastExifRefd) LastExifRefd = DirEnd;
}
for (de=0;de<NumDirEntries;de++){
int Tag, Format, Components;
unsigned char * ValuePtr;
unsigned ByteCount;
char * DirEntry;
DirEntry = (char *)DIR_ENTRY_ADDR(DirStart, de);
Tag = Get16u(DirEntry);
Format = Get16u(DirEntry+2);
Components = Get32u(DirEntry+4);
if ((Format-1) >= NUM_FORMATS) {
// (-1) catches illegal zero case as unsigned underflows to positive large.
throw FatalError("Illegal format code in EXIF dir");
}
if ((unsigned)Components > 0x10000) {
throw FatalError("Illegal number of components for tag");
continue;
}
ByteCount = Components * BytesPerFormat[Format];
if (ByteCount > 4){
unsigned OffsetVal;
OffsetVal = Get32u(DirEntry+8);
// If its bigger than 4 bytes, the dir entry contains an offset.
if (OffsetVal+ByteCount > ExifLength){
// Bogus pointer offset and / or bytecount value
//printf("Offset %d bytes %d ExifLen %d\n",OffsetVal, ByteCount, ExifLength);
throw FatalError("Illegal pointer offset value in EXIF");
}
ValuePtr = OffsetBase+OffsetVal;
}else{
// 4 bytes or less and value is in the dir entry itself
ValuePtr = (unsigned char *)DirEntry+8;
}
if (LastExifRefd < ValuePtr+ByteCount){
// Keep track of last byte in the exif header that was actually referenced.
// That way, we know where the discardable thumbnail data begins.
LastExifRefd = ValuePtr+ByteCount;
}
// Extract useful components of tag
switch(Tag){
case TAG_MAKE:
ExifData::CameraMake = TQString::fromLatin1((const char*)ValuePtr, 31);
break;
case TAG_MODEL:
ExifData::CameraModel = TQString::fromLatin1((const char*)ValuePtr, 39);
break;
case TAG_ORIENTATION:
Orientation = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_DATETIME_ORIGINAL:
DateTime = TQString::fromLatin1((const char*)ValuePtr, 19);
break;
case TAG_USERCOMMENT:
// Olympus has this padded with trailing spaces. Remove these first.
for (a=ByteCount;;){
a--;
if ((ValuePtr)[a] == ' '){
(ValuePtr)[a] = '\0';
}else{
break;
}
if (a == 0) break;
}
// Copy the comment
if (memcmp(ValuePtr, "ASCII",5) == 0){
for (a=5;a<10;a++){
int c;
c = (ValuePtr)[a];
if (c != '\0' && c != ' '){
UserComment = TQString::fromLatin1((const char*)(a+ValuePtr), 199);
break;
}
}
}else{
UserComment = TQString::fromLatin1((const char*)ValuePtr, 199);
}
break;
case TAG_FNUMBER:
// Simplest way of expressing aperture, so I trust it the most.
// (overwrite previously computd value if there is one)
ExifData::ApertureFNumber = (float)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_APERTURE:
case TAG_MAXAPERTURE:
// More relevant info always comes earlier, so only use this field if we don't
// have appropriate aperture information yet.
if (ExifData::ApertureFNumber == 0){
ExifData::ApertureFNumber
= (float)exp(ConvertAnyFormat(ValuePtr, Format)*log(2.0)*0.5);
}
break;
case TAG_FOCALLENGTH:
// Nice digital cameras actually save the focal length as a function
// of how far they are zoomed in.
ExifData::FocalLength = (float)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_SUBJECT_DISTANCE:
// Inidcates the distacne the autofocus camera is focused to.
// Tends to be less accurate as distance increases.
ExifData::Distance = (float)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_EXPOSURETIME:
// Simplest way of expressing exposure time, so I trust it most.
// (overwrite previously computd value if there is one)
ExifData::ExposureTime = (float)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_SHUTTERSPEED:
// More complicated way of expressing exposure time, so only use
// this value if we don't already have it from somewhere else.
if (ExifData::ExposureTime == 0){
ExifData::ExposureTime
= (float)(1/exp(ConvertAnyFormat(ValuePtr, Format)*log(2.0)));
}
break;
case TAG_FLASH:
ExifData::FlashUsed = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_EXIF_IMAGELENGTH:
ExifImageLength = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_EXIF_IMAGEWIDTH:
ExifImageWidth = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_FOCALPLANEXRES:
FocalplaneXRes = ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_FOCALPLANEUNITS:
switch((int)ConvertAnyFormat(ValuePtr, Format)){
case 1: FocalplaneUnits = 25.4; break; // inch
case 2:
// According to the information I was using, 2 means meters.
// But looking at the Cannon powershot's files, inches is the only
// sensible value.
FocalplaneUnits = 25.4;
break;
case 3: FocalplaneUnits = 10; break; // centimeter
case 4: FocalplaneUnits = 1; break; // milimeter
case 5: FocalplaneUnits = .001; break; // micrometer
}
break;
// Remaining cases contributed by: Volker C. Schoech (schoech@gmx.de)
case TAG_EXPOSURE_BIAS:
ExifData::ExposureBias = (float)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_WHITEBALANCE:
ExifData::Whitebalance = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_METERING_MODE:
ExifData::MeteringMode = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_EXPOSURE_PROGRAM:
ExifData::ExposureProgram = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_ISO_EQUIVALENT:
ExifData::ISOequivalent = (int)ConvertAnyFormat(ValuePtr, Format);
if ( ExifData::ISOequivalent < 50 ) ExifData::ISOequivalent *= 200;
break;
case TAG_COMPRESSION_LEVEL:
ExifData::CompressionLevel = (int)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_THUMBNAIL_OFFSET:
ThumbnailOffset = (unsigned)ConvertAnyFormat(ValuePtr, Format);
break;
case TAG_THUMBNAIL_LENGTH:
ThumbnailSize = (unsigned)ConvertAnyFormat(ValuePtr, Format);
break;
}
if (Tag == TAG_EXIF_OFFSET || Tag == TAG_INTEROP_OFFSET){
unsigned char * SubdirStart;
SubdirStart = OffsetBase + Get32u(ValuePtr);
if (SubdirStart <= OffsetBase || SubdirStart >= OffsetBase+ExifLength){
throw FatalError("Illegal subdirectory link");
}
ProcessExifDir(SubdirStart, OffsetBase, ExifLength, NestingLevel+1);
continue;
}
}
{
// In addition to linking to subdirectories via exif tags,
// there's also a potential link to another directory at the end of each
// directory. this has got to be the result of a comitee!
unsigned char * SubdirStart;
unsigned Offset;
if (DIR_ENTRY_ADDR(DirStart, NumDirEntries) + 4 <= OffsetBase+ExifLength){
Offset = Get32u(DIR_ENTRY_ADDR(DirStart, NumDirEntries));
// There is at least one jpeg from an HP camera having an Offset of almost MAXUINT.
// Adding OffsetBase to it produces an overflow, so compare with ExifLength here.
// See http://bugs.kde.org/show_bug.cgi?id=54542
if (Offset && Offset < ExifLength){
SubdirStart = OffsetBase + Offset;
if (SubdirStart > OffsetBase+ExifLength){
if (SubdirStart < OffsetBase+ExifLength+20){
// Jhead 1.3 or earlier would crop the whole directory!
// As Jhead produces this form of format incorrectness,
// I'll just let it pass silently
kdDebug(7034) << "Thumbnail removed with Jhead 1.3 or earlier\n";
}else{
throw FatalError("Illegal subdirectory link 2");
}
}else{
if (SubdirStart <= OffsetBase+ExifLength){
ProcessExifDir(SubdirStart, OffsetBase, ExifLength, NestingLevel+1);
}
}
}
}else{
// The exif header ends before the last next directory pointer.
}
}
if (ThumbnailSize && ThumbnailOffset){
if (ThumbnailSize + ThumbnailOffset < ExifLength){
// The thumbnail pointer appears to be valid. Store it.
Thumbnail.loadFromData(OffsetBase + ThumbnailOffset, ThumbnailSize, "JPEG");
}
}
}
//--------------------------------------------------------------------------
// Process a COM marker. We want to leave the bytes unchanged. The
// progam that displays this text may decide to remove blanks, convert
// newlines, or otherwise modify the text. In particular we want to be
// safe for passing utf-8 text.
//--------------------------------------------------------------------------
void ExifData::process_COM (const uchar * Data, int length)
{
Comment = TQString::fromUtf8((char *)Data+2, (length-2));
}
//--------------------------------------------------------------------------
// Process a SOFn marker. This is useful for the image dimensions
//--------------------------------------------------------------------------
void ExifData::process_SOFn (const uchar * Data, int marker)
{
int data_precision, num_components;
data_precision = Data[2];
ExifData::Height = Get16m(Data+3);
ExifData::Width = Get16m(Data+5);
num_components = Data[7];
if (num_components == 3){
ExifData::IsColor = 1;
}else{
ExifData::IsColor = 0;
}
ExifData::Process = marker;
}
//--------------------------------------------------------------------------
// Get 16 bits motorola order (always) for jpeg header stuff.
//--------------------------------------------------------------------------
int ExifData::Get16m(const void * Short)
{
return (((uchar *)Short)[0] << 8) | ((uchar *)Short)[1];
}
//--------------------------------------------------------------------------
// Process a EXIF marker
// Describes all the drivel that most digital cameras include...
//--------------------------------------------------------------------------
void ExifData::process_EXIF(unsigned char * CharBuf, unsigned int length)
{
ExifData::FlashUsed = 0; // If it s from a digicam, and it used flash, it says so.
FocalplaneXRes = 0;
FocalplaneUnits = 0;
ExifImageWidth = 0;
ExifImageLength = 0;
{ // Check the EXIF header component
static const uchar ExifHeader[] = "Exif\0\0";
if (memcmp(CharBuf+2, ExifHeader,6)){
throw FatalError("Incorrect Exif header");
}
}
if (memcmp(CharBuf+8,"II",2) == 0){
// printf("Exif section in Intel order\n");
MotorolaOrder = 0;
}else{
if (memcmp(CharBuf+8,"MM",2) == 0){
// printf("Exif section in Motorola order\n");
MotorolaOrder = 1;
}else{
throw FatalError("Invalid Exif alignment marker.");
}
}
// Check the next two values for correctness.
if (Get16u(CharBuf+10) != 0x2a){
throw FatalError("Invalid Exif start (1)");
}
long IFDoffset = Get32u(CharBuf+12);
LastExifRefd = CharBuf;
// First directory starts 16 bytes in. Offsets start at 8 bytes in.
ProcessExifDir(&CharBuf[8+IFDoffset], CharBuf+8, length-6, 0);
// This is how far the interesting (non thumbnail) part of the exif went.
ExifSettingsLength = LastExifRefd - CharBuf;
// Compute the CCD width, in milimeters.
if (FocalplaneXRes != 0){
kdDebug(7034) << "ExifImageWidth " << ExifImageWidth << " FocalplaneUnits " << FocalplaneUnits << " FocalplaneXRes " << FocalplaneXRes << endl;
ExifData::CCDWidth = (float)(ExifImageWidth * FocalplaneUnits / FocalplaneXRes);
}
}
//--------------------------------------------------------------------------
// Convert exif time to Unix time structure
//--------------------------------------------------------------------------
int ExifData::Exif2tm(struct tm * timeptr, char * ExifTime)
{
int a;
timeptr->tm_wday = -1;
// Check for format: YYYY:MM:DD HH:MM:SS format.
a = sscanf(ExifTime, "%d:%d:%d %d:%d:%d",
&timeptr->tm_year, &timeptr->tm_mon, &timeptr->tm_mday,
&timeptr->tm_hour, &timeptr->tm_min, &timeptr->tm_sec);
if (a == 6){
timeptr->tm_isdst = -1;
timeptr->tm_mon -= 1; // Adjust for unix zero-based months
timeptr->tm_year -= 1900; // Adjust for year starting at 1900
return true; // worked.
}
return false; // Wasn't in Exif date format.
}
//--------------------------------------------------------------------------
// Contructor for initialising
//--------------------------------------------------------------------------
ExifData::ExifData()
{
ExifData::Whitebalance = -1;
ExifData::MeteringMode = -1;
ExifData::FlashUsed = 0;
Orientation = 0;
Height = 0;
Width = 0;
IsColor = 0;
Process = 0;
FocalLength = 0;
ExposureTime = 0;
ApertureFNumber = 0;
Distance = 0;
CCDWidth = 0;
ExposureBias = 0;
ExposureProgram = 0;
ISOequivalent = 0;
CompressionLevel = 0;
}
//--------------------------------------------------------------------------
// process a EXIF jpeg file
//--------------------------------------------------------------------------
bool ExifData::scan(const TQString & path)
{
int ret;
TQFile f(path);
if ( !f.open(IO_ReadOnly) )
return false;
try {
// Scan the JPEG headers.
ret = ReadJpegSections(f, READ_EXIF);
}
catch (FatalError& e) {
e.debug_print();
f.close();
return false;
}
if (ret == false){
kdDebug(7034) << "Not JPEG file!\n";
DiscardData();
f.close();
return false;
}
f.close();
DiscardData();
//now make the strings clean,
// for exmaple my Casio is a "QV-4000 "
CameraMake = CameraMake.stripWhiteSpace();
CameraModel = CameraModel.stripWhiteSpace();
UserComment = UserComment.stripWhiteSpace();
Comment = Comment.stripWhiteSpace();
return true;
}
//--------------------------------------------------------------------------
// Does the embedded thumbnail match the jpeg image?
//--------------------------------------------------------------------------
#ifndef JPEG_TOL
#define JPEG_TOL 0.02
#endif
bool ExifData::isThumbnailSane() {
if (Thumbnail.isNull()) return false;
// check whether thumbnail dimensions match the image
// not foolproof, but catches some altered images (jpegtran -rotate)
if (ExifImageLength != 0 && ExifImageLength != Height) return false;
if (ExifImageWidth != 0 && ExifImageWidth != Width) return false;
if (Thumbnail.width() == 0 || Thumbnail.height() == 0) return false;
if (Height == 0 || Width == 0) return false;
double d = (double)Height/Width*Thumbnail.width()/Thumbnail.height();
return (1-JPEG_TOL < d) && (d < 1+JPEG_TOL);
}
//--------------------------------------------------------------------------
// return a thumbnail that respects the orientation flag
// only if it seems sane
//--------------------------------------------------------------------------
TQImage ExifData::getThumbnail() {
if (!isThumbnailSane()) return NULL;
if (!Orientation || Orientation == 1) return Thumbnail;
// now fix orientation
TQWMatrix M;
TQWMatrix flip= TQWMatrix(-1,0,0,1,0,0);
switch (Orientation) { // notice intentional fallthroughs
case 2: M = flip; break;
case 4: M = flip;
case 3: M.rotate(180); break;
case 5: M = flip;
case 6: M.rotate(90); break;
case 7: M = flip;
case 8: M.rotate(270); break;
default: break; // should never happen
}
return Thumbnail.xForm(M);
}
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