/*-------------------------------------------------------------

tiio_jpg_exif.h

Based on source code of a public domain software "Exif Jpeg header manipulation

tool (jhead)" by Matthias Wandel.

For now it is used only for obtaining resolution values.

http://www.sentex.net/~mwandel/jhead/

-------------------------------------------------------------*/

#pragma once

#ifndef TIIO_JPG_EXIF_H

#define TIIO_JPG_EXIF_H

#include <stdlib.h></stdlib.h>

// undefining ReadAllTags will load only resolution information

#define ReadAllTags

#undef ReadAllTags

#define MAX_COMMENT_SIZE 16000

#define MAX_DATE_COPIES 10

#ifdef _WIN32

#define PATH_MAX _MAX_PATH

#define SLASH '\\'

#else

#ifndef PATH_MAX

#define PATH_MAX 1024

#endif

#define SLASH '/'

#endif

class JpgExifReader {

  enum FORMATS {

    FMT_BYTE = 1,

    FMT_STRING,

    FMT_USHORT,

    FMT_ULONG,

    FMT_URATIONAL,

    FMT_SBYTE,

    FMT_UNDEFINED,

    FMT_SSHORT,

    FMT_SLONG,

    FMT_SRATIONAL,

    FMT_SINGLE,

    FMT_DOUBLE

  };

  int NUM_FORMATS = FMT_DOUBLE;

  struct ExifImageInfo {

    float xResolution = 0.0;

    float yResolution = 0.0;

    int ResolutionUnit;

#ifdef ReadAllTags

    char FileName[PATH_MAX + 1];

    time_t FileDateTime;

    unsigned FileSize;

    char CameraMake[32];

    char CameraModel[40];

    char DateTime[20];

    unsigned Height, Width;

    int Orientation;

    int IsColor;

    int Process;

    int FlashUsed;

    float FocalLength;

    float ExposureTime;

    float ApertureFNumber;

    float Distance;

    float CCDWidth;

    float ExposureBias;

    float DigitalZoomRatio;

    int FocalLength35mmEquiv;  // Exif 2.2 tag - usually not present.

    int Whitebalance;

    int MeteringMode;

    int ExposureProgram;

    int ExposureMode;

    int ISOequivalent;

    int LightSource;

    int DistanceRange;

    char Comments[MAX_COMMENT_SIZE];

    int CommentWidthchars;  // If nonzero, widechar comment, indicates number of

                            // chars.

    unsigned ThumbnailOffset;    // Exif offset to thumbnail

    unsigned ThumbnailSize;      // Size of thumbnail.

    unsigned LargestExifOffset;  // Last exif data referenced (to check if

                                 // thumbnail is at end)

    char ThumbnailAtEnd;  // Exif header ends with the thumbnail

    // (we can only modify the thumbnail if its at the end)

    int ThumbnailSizeOffset;

    int DateTimeOffsets[MAX_DATE_COPIES];

    int numDateTimeTags = 0;

    int GpsInfoPresent;

    char GpsLat[31];

    char GpsLong[31];

    char GpsAlt[20];

    int QualityGuess;

#endif

  } ImageInfo;

#ifdef ReadAllTags

  unsigned char* DirWithThumbnailPtrs;

  double FocalplaneXRes;

  double FocalplaneUnits;

  int ExifImageWidth;

  // for fixing the rotation.

  void* OrientationPtr[2];

  int OrientationNumFormat[2];

  int NumOrientations = 0;

#endif

  int MotorolaOrder = 0;

  int Get16u(void* Short);

  unsigned Get32u(void* Long);

  int Get32s(void* Long);

  void PrintFormatNumber(void* ValuePtr, int Format, int ByteCount);

  double ConvertAnyFormat(void* ValuePtr, int Format);

public:

  void process_EXIF(unsigned char* ExifSection, unsigned int length);

  void ProcessExifDir(unsigned char* DirStart, unsigned char* OffsetBase,

                      unsigned ExifLength, int NestingLevel);

  // obtaining resolution info

  bool containsResolution() { return ImageInfo.xResolution != 0.0; }

  float getXResolution() { return ImageInfo.xResolution; }

  float getYResolution() { return ImageInfo.yResolution; }

  int getResolutionUnit() { return ImageInfo.ResolutionUnit; }

};

#endif