exif class added (taken from opie-eye_slave and more c++ like reworked)

it is used in oimageview while loading jpegs checking BEFORE loading if the
image should be scaled loaded.
ToDo: documentation of the interface, remove it from opie-eye_slave (it should
use of course the library version)

1 files changed, 1195 insertions, 0 deletions

diff --git a/libopie2/opiemm/opieexif.cpp b/libopie2/opiemm/opieexif.cpp
new file mode 100644
index 0000000..0860ea8
--- a/dev/null
+++ b/libopie2/opiemm/opieexif.cpp
@@ -0,0 +1,1195 @@
+#include "opieexif.h"
+
+/* OPIE */
+#include <opie2/odebug.h>
+#include <qpe/timestring.h>
+/* QT */
+#include <qobject.h>
+#include <qimage.h>
+
+/**
+    exif.h
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <time.h>
+
+#include <qstring.h>
+#include <qfile.h>
+#include <qimage.h>
+
+//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
+
+
+//--------------------------------------------------------------------------
+// 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
+
+
+
+namespace Opie {
+
+namespace MM {
+
+class FatalError {
+    const char* ex;
+public:
+    FatalError(const char* s) { ex = s; }
+    void debug_print() const { owarn << "exception: " << ex << "" << oendl;  }
+};
+
+ExifData::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"}
+};
+
+//--------------------------------------------------------------------------
+// Parse the marker stream until SOS or EOI is seen;
+//--------------------------------------------------------------------------
+int ExifData::ReadJpegSections (QFile & 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){
+
+                owarn << "too many padding bytes" << oendl;
+                return false;
+
+            }
+        }
+
+        if (marker == 0xff){
+            // 0xff is legal padding, but if we get that many, something's wrong.
+            return false;
+        }
+
+        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) {
+            return false;;
+        }
+
+        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){
+            return false;
+        }
+        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 = QMAX( 0ul, infile.size()-infile.at() );
+                    Data = (uchar *)malloc(size);
+                    if (Data == NULL){
+                        return false;
+                    }
+
+                    got = infile.readBlock((char*)Data,  size);
+                    if (( unsigned ) got != size){
+                        return false;
+                    }
+
+                    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
+                owarn << "No image in jpeg!" << oendl;
+                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);
+                }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);
+            default:
+                break;
+                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)
+{
+    int de;
+    int a;
+    int NumDirEntries;
+    unsigned ThumbnailOffset = 0;
+    unsigned ThumbnailSize = 0;
+
+    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.
+                return;
+            }
+        }
+        if (DirEnd < LastExifRefd) LastExifRefd = DirEnd;
+    }
+
+    for (de=0;de<NumDirEntries;de++){
+        int Tag, Format, Components;
+        unsigned char * ValuePtr;
+        int 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.
+            return;
+        }
+
+        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);
+
+                return;
+            }
+            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 = QString((char*)ValuePtr);
+                break;
+
+            case TAG_MODEL:
+                ExifData::CameraModel = QString((char*)ValuePtr);
+        break;
+
+            case TAG_ORIENTATION:
+                Orientation = (int)ConvertAnyFormat(ValuePtr, Format);
+                break;
+
+            case TAG_DATETIME_ORIGINAL:
+        DateTime = QString((char*)ValuePtr);
+                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 != ' '){
+                            //strncpy(ImageInfo.Comments, (const char*)(a+ValuePtr), 199);
+                            UserComment.sprintf("%s", (const char*)(a+ValuePtr));
+                            break;
+                        }
+                    }
+                }else{
+                    //strncpy(ImageInfo.Comments, (const char*)ValuePtr, 199);
+                    UserComment.sprintf("%s", (const char*)ValuePtr);
+                }
+                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)*0.5);
+                }
+                break;
+
+            case TAG_FOCALLENGTH:
+                // Nice digital cameras actually save the focal length as a function
+                // of how farthey 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)));
+                }
+                break;
+
+            case TAG_FLASH:
+                if (ConvertAnyFormat(ValuePtr, Format)){
+                    ExifData::FlashUsed = 1;
+                }
+                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){
+                return;
+            }
+            ProcessExifDir(SubdirStart, OffsetBase, ExifLength);
+            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
+                        owarn << "Thumbnail removed with Jhead 1.3 or earlier" << oendl;
+                    }else{
+                        return;
+                    }
+                }else{
+                    if (SubdirStart <= OffsetBase+ExifLength){
+                        ProcessExifDir(SubdirStart, OffsetBase, ExifLength);
+                    }
+                }
+            }
+        }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)
+{
+    QChar ch;
+    int a;
+
+    for (a=2;a<length;a++){
+        ch = Data[a];
+        if (ch == '\000') continue;                     // Remove nulls
+        Comment.append(ch);
+    }
+}
+
+
+//--------------------------------------------------------------------------
+// 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)){
+            return;
+        }
+    }
+
+    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{
+            return;
+        }
+    }
+
+    // Check the next two values for correctness.
+    if (Get16u(CharBuf+10) != 0x2a
+      || Get32u(CharBuf+12) != 0x08){
+        return;
+    }
+
+    LastExifRefd = CharBuf;
+
+    // First directory starts 16 bytes in.  Offsets start at 8 bytes in.
+    ProcessExifDir(CharBuf+16, CharBuf+8, length-6);
+
+    // 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){
+        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 = -1;
+    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;
+    MotorolaOrder = 0;
+}
+
+ExifData::~ExifData()
+{
+}
+
+//--------------------------------------------------------------------------
+// process a EXIF jpeg file
+//--------------------------------------------------------------------------
+bool ExifData::scan(const QString & path)
+{
+    int ret;
+
+    QFile f(path);
+    f.open(IO_ReadOnly);
+
+    // Scan the JPEG headers.
+    ret = ReadJpegSections(f, READ_EXIF);
+
+    if (ret == false){
+        owarn << "Not JPEG file!" << oendl;
+        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);
+}
+
+
+
+static QImage flip_image( const QImage& img );
+static QImage rotate_90( const QImage& img );
+static QImage rotate_180( const QImage& );
+static QImage rotate_270( const QImage& );
+
+//--------------------------------------------------------------------------
+// return a thumbnail that respects the orientation flag
+// only if it seems sane
+//--------------------------------------------------------------------------
+QImage ExifData::getThumbnail() {
+  if (!isThumbnailSane()) return NULL;
+  if (!Orientation || Orientation == 1) return Thumbnail;
+
+  // now fix orientation
+
+  QImage dest = Thumbnail;
+  switch (Orientation) {  // notice intentional fallthroughs
+    case 2: dest = flip_image( dest ); break;
+    case 4: dest = flip_image( dest );
+    case 3: dest =rotate_180( dest ); break;
+    case 5: dest = flip_image( dest );
+    case 6: dest = rotate_90( dest ); break;
+    case 7: dest = flip_image( dest );
+    case 8: dest = rotate_270( dest ); break;
+    default: break; // should never happen
+  }
+  return dest;
+}
+
+
+/*
+ *
+ */
+static QImage flip_image( const QImage& img ) {
+    return img.mirror( TRUE, FALSE );
+}
+
+
+static QImage dest;
+static int x, y;
+static unsigned int  *srcData, *destData; // we're not threaded anyway
+static unsigned char *srcData8, *destData8; // 8 bit is char
+static unsigned int *srcTable,  *destTable; // destination table
+
+
+static QImage rotate_90_8( const QImage &img ) {
+    dest.create(img.height(), img.width(), img.depth());
+    dest.setNumColors(img.numColors());
+    srcTable = (unsigned int *)img.colorTable();
+    destTable = (unsigned int *)dest.colorTable();
+    for ( x=0; x < img.numColors(); ++x )
+        destTable[x] = srcTable[x];
+    for ( y=0; y < img.height(); ++y ){
+        srcData8 = (unsigned char *)img.scanLine(y);
+        for ( x=0; x < img.width(); ++x ){
+            destData8 = (unsigned char *)dest.scanLine(x);
+            destData8[img.height()-y-1] = srcData8[x];
+        }
+    }
+    return dest;
+}
+
+static QImage rotate_90_all(  const QImage& img ) {
+    dest.create(img.height(), img.width(), img.depth());
+    for ( y=0; y < img.height(); ++y )    {
+        srcData = (unsigned int *)img.scanLine(y);
+        for ( x=0; x < img.width(); ++x ) {
+            destData = (unsigned int *)dest.scanLine(x);
+            destData[img.height()-y-1] = srcData[x];
+        }
+    }
+
+    return dest;
+}
+
+
+static QImage  rotate_90( const QImage & img ) {
+    if ( img.depth() > 8)
+        return rotate_90_all( img );
+    else
+        return rotate_90_8( img );
+}
+
+static QImage rotate_180_all( const QImage& img ) {
+    dest.create(img.width(), img.height(), img.depth());
+    for ( y=0; y < img.height(); ++y ){
+        srcData = (unsigned int *)img.scanLine(y);
+        destData = (unsigned int *)dest.scanLine(img.height()-y-1);
+        for ( x=0; x < img.width(); ++x )
+            destData[img.width()-x-1] = srcData[x];
+    }
+    return dest;
+}
+
+static QImage rotate_180_8( const QImage& img ) {
+    dest.create(img.width(), img.height(), img.depth());
+    dest.setNumColors(img.numColors());
+    srcTable = (unsigned int *)img.colorTable();
+    destTable = (unsigned int *)dest.colorTable();
+    for ( x=0; x < img.numColors(); ++x )
+        destTable[x] = srcTable[x];
+    for ( y=0; y < img.height(); ++y ){
+        srcData8 = (unsigned char *)img.scanLine(y);
+        destData8 = (unsigned char *)dest.scanLine(img.height()-y-1);
+        for ( x=0; x < img.width(); ++x )
+            destData8[img.width()-x-1] = srcData8[x];
+    }
+    return dest;
+}
+
+static QImage rotate_180( const QImage& img ) {
+    if ( img.depth() > 8 )
+        return rotate_180_all( img );
+    else
+        return rotate_180_8( img );
+}
+
+
+static QImage rotate_270_8( const QImage& img ) {
+    dest.create(img.height(), img.width(), img.depth());
+    dest.setNumColors(img.numColors());
+    srcTable = (unsigned int *)img.colorTable();
+    destTable = (unsigned int *)dest.colorTable();
+    for ( x=0; x < img.numColors(); ++x )
+        destTable[x] = srcTable[x];
+    for ( y=0; y < img.height(); ++y ){
+        srcData8 = (unsigned char *)img.scanLine(y);
+        for ( x=0; x < img.width(); ++x ){
+            destData8 = (unsigned char *)dest.scanLine(img.width()-x-1);
+            destData8[y] = srcData8[x];
+        }
+    }
+
+    return dest;
+}
+
+static QImage rotate_270_all( const QImage& img ) {
+    dest.create(img.height(), img.width(), img.depth());
+    for ( y=0; y < img.height(); ++y ){
+        srcData = (unsigned int *)img.scanLine(y);
+        for ( x=0; x < img.width(); ++x ){
+            destData = (unsigned int *)dest.scanLine(img.width()-x-1);
+            destData[y] = srcData[x];
+        }
+    }
+    return dest;
+}
+
+static QImage rotate_270( const QImage& img ) {
+    if (  img.depth() > 8 )
+        return rotate_270_all( img );
+    else
+        return rotate_270_8( img );
+}
+
+
+static QString color_mode_to_string( bool b ) {
+    return b ? QObject::tr( "Colormode: Color\n" ) : QObject::tr( "Colormode: Black and white\n" );
+}
+
+static QString compression_to_string( int level ) {
+    QString str;
+    switch( level ) {
+    case 1:
+        str = QObject::tr( "Basic" );
+        break;
+    case 2:
+        str = QObject::tr( "Normal" );
+        break;
+    case 4:
+        str = QObject::tr( "Fine" );
+        break;
+    default:
+        str = QObject::tr( "Unknown" );
+
+    }
+    return QObject::tr("Quality: %1\n").arg(str);
+}
+
+
+static QDateTime parseDateTime( const QString& string )
+{
+    QDateTime dt;
+    if ( string.length() != 19 )
+        return dt;
+
+    QString year    = string.left( 4 );
+    QString month   = string.mid( 5, 2 );
+    QString day     = string.mid( 8, 2 );
+    QString hour    = string.mid( 11, 2 );
+    QString minute  = string.mid( 14, 2 );
+    QString seconds = string.mid( 18, 2 );
+
+    bool ok;
+    bool allOk = true;
+    int y  = year.toInt( &ok );
+    allOk &= ok;
+
+    int mo = month.toInt( &ok );
+    allOk &= ok;
+
+    int d  = day.toInt( &ok );
+    allOk &= ok;
+
+    int h  = hour.toInt( &ok );
+    allOk &= ok;
+
+    int mi = minute.toInt( &ok );
+    allOk &= ok;
+
+    int s  = seconds.toInt( &ok );
+    allOk &= ok;
+
+    if ( allOk ) {
+        dt.setDate( QDate( y, mo, d ) );
+        dt.setTime( QTime( h, mi, s ) );
+    }
+
+    return dt;
+}
+
+static QString white_balance_string( int i ) {
+    QString balance;
+    switch ( i ) {
+    case 0:
+        balance = QObject::tr( "Unknown" );
+        break;
+    case 1:
+        balance = QObject::tr( "Daylight" );
+        break;
+    case 2:
+        balance = QObject::tr( "Fluorescent" );
+        break;
+    case 3:
+        balance = QObject::tr( "Tungsten" );
+        break;
+    case 17:
+        balance = QObject::tr( "Standard light A" );
+        break;
+    case 18:
+        balance = QObject::tr( "Standard light B" );
+        break;
+    case 19:
+        balance = QObject::tr( "Standard light C" );
+        break;
+    case 20:
+        balance = QObject::tr( "D55" );
+        break;
+    case 21:
+        balance = QObject::tr( "D65" );
+        break;
+    case 22:
+        balance = QObject::tr( "D75" );
+        break;
+    case 255:
+        balance = QObject::tr( "Other" );
+        break;
+    default:
+        balance = QObject::tr( "Unknown" );
+    }
+    return QObject::tr( "White Balance: %1\n" ).arg( balance );
+
+}
+
+
+static QString metering_mode( int i) {
+    QString meter;
+    switch( i ) {
+    case 0:
+        meter = QObject::tr( "Unknown" );
+        break;
+    case 1:
+        meter = QObject::tr( "Average" );
+        break;
+    case 2:
+        meter = QObject::tr( "Center weighted average" );
+        break;
+    case 3:
+        meter = QObject::tr( "Spot" );
+        break;
+    case 4:
+        meter = QObject::tr( "MultiSpot" );
+        break;
+    case 5:
+        meter = QObject::tr( "Pattern" );
+        break;
+    case 6:
+        meter = QObject::tr( "Partial" );
+        break;
+    case 255:
+        meter = QObject::tr( "Other" );
+        break;
+    default:
+        meter = QObject::tr( "Unknown" );
+    }
+
+    return QObject::tr( "Metering Mode: %1\n" ).arg( meter );
+}
+
+
+static QString exposure_program( int i ) {
+    QString exp;
+    switch( i ) {
+    case 0:
+        exp = QObject::tr( "Not defined" );
+        break;
+    case 1:
+        exp = QObject::tr( "Manual" );
+        break;
+    case 2:
+        exp = QObject::tr( "Normal progam" );
+        break;
+    case 3:
+        exp = QObject::tr( "Aperture priority" );
+        break;
+    case 4:
+        exp = QObject::tr( "Shutter priority" );
+        break;
+    case 5:
+        exp = QObject::tr( "Creative progam\n(biased toward fast shutter speed" );
+        break;
+    case 6:
+        exp = QObject::tr( "Action progam\n(biased toward fast shutter speed)" );
+        break;
+    case 7:
+        exp = QObject::tr( "Portrait mode\n(for closeup photos with the background out of focus)" );
+        break;
+    case 8:
+        exp = QObject::tr( "Landscape mode\n(for landscape photos with the background in focus)" );
+        break;
+    default:
+        exp = QObject::tr( "Unknown" );
+    }
+
+    return QObject::tr( "Exposure Program: %1\n" ).arg( exp );
+}
+
+} // namespace MM
+} // namespace OPIE