[imager.git] / imexif.c

#include "imexif.h"
#include <stdlib.h>
#include <float.h>

/*
=head1 NAME

imexif.c - EXIF support for Imager

=head1 SYNOPSIS

  if (i_int_decode_exif(im, app1data, app1datasize)) {
    // exif block seen
  }

=head1 DESCRIPTION

This code provides a basic EXIF data decoder.  It is intended to be
called from the JPEG reader code when an APP1 data block is found, and
will set tags in the supplied image.

=cut
*/

typedef enum tiff_type_tag {
  tt_intel = 'I',
  tt_motorola = 'M'
} tiff_type;

typedef enum {
  ift_byte = 1,
  ift_ascii = 2,
  ift_short = 3,
  ift_long = 4,
  ift_rational = 5,
  ift_sbyte = 6,
  ift_undefined = 7,
  ift_sshort = 8,
  ift_slong = 9,
  ift_srational = 10,
  ift_float = 11,
  ift_double = 12,
  ift_last = 12 /* keep the same as the highest type code */
} ifd_entry_type;

static int type_sizes[] =
  {
    0, /* not used */
    1, /* byte */
    1, /* ascii */
    2, /* short */
    4, /* long */
    8, /* rational */
    1, /* sbyte */
    1, /* undefined */
    2, /* sshort */
    4, /* slong */
    8, /* srational */
    4, /* float */
    8, /* double */
  };

typedef struct {
  int tag;
  int type;
  int count;
  int item_size;
  int size;
  int offset;
} ifd_entry;

typedef struct {
  int tag;
  char const *name;
} tag_map;

typedef struct {
  int tag;
  char const *name;
  tag_map const *map;
  int map_count;
} tag_value_map;

#define PASTE(left, right) PASTE_(left, right)
#define PASTE_(left, right) left##right
#define QUOTE(value) #value

#define VALUE_MAP_ENTRY(name) \
  { \
    PASTE(tag_, name), \
    "exif_" QUOTE(name) "_name", \
    PASTE(name, _values), \
    ARRAY_COUNT(PASTE(name, _values)) \
  }

/* we don't process every tag */
#define tag_make 271
#define tag_model 272
#define tag_orientation 274
#define tag_x_resolution 282
#define tag_y_resolution 283
#define tag_resolution_unit 296
#define tag_copyright 33432
#define tag_software 305
#define tag_artist 315
#define tag_date_time 306
#define tag_image_description 270

#define tag_exif_ifd 34665
#define tag_gps_ifd 34853

#define resunit_none 1
#define resunit_inch 2
#define resunit_centimeter 3

/* tags from the EXIF ifd */
#define tag_exif_version 0x9000
#define tag_flashpix_version 0xA000
#define tag_color_space 0xA001
#define tag_component_configuration 0x9101
#define tag_component_bits_per_pixel 0x9102
#define tag_pixel_x_dimension 0xA002
#define tag_pixel_y_dimension 0xA003
#define tag_maker_note 0x927C
#define tag_user_comment 0x9286
#define tag_related_sound_file 0xA004
#define tag_date_time_original 0x9003
#define tag_date_time_digitized 0x9004
#define tag_sub_sec_time 0x9290
#define tag_sub_sec_time_original 0x9291
#define tag_sub_sec_time_digitized 0x9292
#define tag_image_unique_id 0xA420
#define tag_exposure_time 0x829a
#define tag_f_number 0x829D
#define tag_exposure_program 0x8822
#define tag_spectral_sensitivity 0x8824
#define tag_iso_speed_ratings 0x8827
#define tag_oecf 0x8828
#define tag_shutter_speed 0x9201
#define tag_aperture 0x9202
#define tag_brightness 0x9203
#define tag_exposure_bias 0x9204
#define tag_max_aperture 0x9205
#define tag_subject_distance 0x9206
#define tag_metering_mode 0x9207
#define tag_light_source 0x9208
#define tag_flash 0x9209
#define tag_focal_length 0x920a
#define tag_subject_area 0x9214
#define tag_flash_energy 0xA20B
#define tag_spatial_frequency_response 0xA20C
#define tag_focal_plane_x_resolution 0xA20e
#define tag_focal_plane_y_resolution 0xA20F
#define tag_focal_plane_resolution_unit 0xA210
#define tag_subject_location 0xA214
#define tag_exposure_index 0xA215
#define tag_sensing_method 0xA217
#define tag_file_source 0xA300
#define tag_scene_type 0xA301
#define tag_cfa_pattern 0xA302
#define tag_custom_rendered 0xA401
#define tag_exposure_mode 0xA402
#define tag_white_balance 0xA403
#define tag_digital_zoom_ratio 0xA404
#define tag_focal_length_in_35mm_film 0xA405
#define tag_scene_capture_type 0xA406
#define tag_gain_control 0xA407
#define tag_contrast 0xA408
#define tag_saturation 0xA409
#define tag_sharpness 0xA40A
#define tag_device_setting_description 0xA40B
#define tag_subject_distance_range 0xA40C

/* GPS tags */
#define tag_gps_version_id 0
#define tag_gps_latitude_ref 1
#define tag_gps_latitude 2
#define tag_gps_longitude_ref 3
#define tag_gps_longitude 4
#define tag_gps_altitude_ref 5
#define tag_gps_altitude 6
#define tag_gps_time_stamp 7
#define tag_gps_satellites 8
#define tag_gps_status 9
#define tag_gps_measure_mode 10
#define tag_gps_dop 11
#define tag_gps_speed_ref 12
#define tag_gps_speed 13
#define tag_gps_track_ref 14
#define tag_gps_track 15
#define tag_gps_img_direction_ref 16
#define tag_gps_img_direction 17
#define tag_gps_map_datum 18
#define tag_gps_dest_latitude_ref 19
#define tag_gps_dest_latitude 20
#define tag_gps_dest_longitude_ref 21
#define tag_gps_dest_longitude 22
#define tag_gps_dest_bearing_ref 23
#define tag_gps_dest_bearing 24
#define tag_gps_dest_distance_ref 25
#define tag_gps_dest_distance 26
#define tag_gps_processing_method 27
#define tag_gps_area_information 28
#define tag_gps_date_stamp 29
#define tag_gps_differential 30

/* don't use this on pointers */
#define ARRAY_COUNT(array) (sizeof(array)/sizeof(*array))

/* in memory tiff structure */
typedef struct {
  /* the data we use as a tiff */
  unsigned char *base;
  size_t size;

  /* intel or motorola byte order */
  tiff_type type;

  /* initial ifd offset */
  unsigned long first_ifd_offset;
  
  /* size (in entries) and data */
  int ifd_size; 
  ifd_entry *ifd;
  unsigned long next_ifd;
} imtiff;

static int tiff_init(imtiff *tiff, unsigned char *base, size_t length);
static int tiff_load_ifd(imtiff *tiff, unsigned long offset);
static void tiff_final(imtiff *tiff);
static void tiff_clear_ifd(imtiff *tiff);
#if 0 /* currently unused, but that may change */
static int tiff_get_bytes(imtiff *tiff, unsigned char *to, size_t offset, 
			  size_t count);
#endif
static int tiff_get_tag_double(imtiff *, int index, double *result);
static int tiff_get_tag_int(imtiff *, int index, int *result);
static unsigned tiff_get16(imtiff *, unsigned long offset);
static unsigned tiff_get32(imtiff *, unsigned long offset);
static int tiff_get16s(imtiff *, unsigned long offset);
static int tiff_get32s(imtiff *, unsigned long offset);
static double tiff_get_rat(imtiff *, unsigned long offset);
static double tiff_get_rats(imtiff *, unsigned long offset);
static void save_ifd0_tags(i_img *im, imtiff *tiff, unsigned long *exif_ifd_offset, unsigned long *gps_ifd_offset);
static void save_exif_ifd_tags(i_img *im, imtiff *tiff);
static void save_gps_ifd_tags(i_img *im, imtiff *tiff);
static void
copy_string_tags(i_img *im, imtiff *tiff, tag_map *map, int map_count);
static void
copy_int_tags(i_img *im, imtiff *tiff, tag_map *map, int map_count);
static void
copy_rat_tags(i_img *im, imtiff *tiff, tag_map *map, int map_count);
static void
copy_num_array_tags(i_img *im, imtiff *tiff, tag_map *map, int map_count);
static void
copy_name_tags(i_img *im, imtiff *tiff, tag_value_map *map, int map_count);
static void process_maker_note(i_img *im, imtiff *tiff, unsigned long offset, size_t size);

/*
=head1 PUBLIC FUNCTIONS

These functions are available to other parts of Imager.  They aren't
intended to be called from outside of Imager.

=over

=item i_int_decode_exit

i_int_decode_exif(im, data_base, data_size);

The data from data_base for data_size bytes will be scanned for EXIF
data.

Any data found will be used to set tags in the supplied image.

The intent is that invalid EXIF data will simply fail to set tags, and
write to the log.  In no case should this code exit when supplied
invalid data.

Returns true if an Exif header was seen.

*/

int
i_int_decode_exif(i_img *im, unsigned char *data, size_t length) {
  imtiff tiff;
  unsigned long exif_ifd_offset = 0;
  unsigned long gps_ifd_offset = 0;
  /* basic checks - must start with "Exif\0\0" */

  if (length < 6 || memcmp(data, "Exif\0\0", 6) != 0) {
    return 0;
  }

  data += 6;
  length -= 6;

  if (!tiff_init(&tiff, data, length)) {
    mm_log((2, "Exif header found, but no valid TIFF header\n"));
    return 1;
  }
  if (!tiff_load_ifd(&tiff, tiff.first_ifd_offset)) {
    mm_log((2, "Exif header found, but could not load IFD 0\n"));
    tiff_final(&tiff);
    return 1;
  }

  save_ifd0_tags(im, &tiff, &exif_ifd_offset, &gps_ifd_offset);

  if (exif_ifd_offset) {
    if (tiff_load_ifd(&tiff, exif_ifd_offset)) {
      save_exif_ifd_tags(im, &tiff);
    }
    else {
      mm_log((2, "Could not load Exif IFD\n"));
    }
  }

  if (gps_ifd_offset) {
    if (tiff_load_ifd(&tiff, gps_ifd_offset)) {
      save_gps_ifd_tags(im, &tiff);
    }
    else {
      mm_log((2, "Could not load GPS IFD\n"));
    }
  }

  tiff_final(&tiff);

  return 1;
}

/*

=back

=head1 INTERNAL FUNCTIONS

=head2 EXIF Processing 

=over

=item save_ifd0_tags

save_ifd0_tags(im, tiff, &exif_ifd_offset, &gps_ifd_offset)

Scans the currently loaded IFD for tags expected in IFD0 and sets them
in the image.

Sets *exif_ifd_offset to the offset of the EXIF IFD if found.

=cut

*/

static tag_map ifd0_string_tags[] =
  {
    { tag_make, "exif_make" },
    { tag_model, "exif_model" },
    { tag_copyright, "exif_copyright" },
    { tag_software, "exif_software" },
    { tag_artist, "exif_artist" },
    { tag_date_time, "exif_date_time" },
    { tag_image_description, "exif_image_description" },
  };

static const int ifd0_string_tag_count = ARRAY_COUNT(ifd0_string_tags);

static tag_map ifd0_int_tags[] =
  {
    { tag_orientation, "exif_orientation", },
    { tag_resolution_unit, "exif_resolution_unit" },
  };

static const int ifd0_int_tag_count = ARRAY_COUNT(ifd0_int_tags);

static tag_map ifd0_rat_tags[] =
  {
    { tag_x_resolution, "exif_x_resolution" },
    { tag_y_resolution, "exif_y_resolution" },
  };

static tag_map resolution_unit_values[] =
  {
    { 1, "none" },
    { 2, "inches" },
    { 3, "centimeters" },
  };

static tag_value_map ifd0_values[] =
  {
    VALUE_MAP_ENTRY(resolution_unit),
  };

static void
save_ifd0_tags(i_img *im, imtiff *tiff, unsigned long *exif_ifd_offset,
	       unsigned long *gps_ifd_offset) {
  int tag_index;
  int work;
  ifd_entry *entry;

  for (tag_index = 0, entry = tiff->ifd; 
       tag_index < tiff->ifd_size; ++tag_index, ++entry) {
    switch (entry->tag) {
    case tag_exif_ifd:
      if (tiff_get_tag_int(tiff, tag_index, &work))
	*exif_ifd_offset = work;
      break;

    case tag_gps_ifd:
      if (tiff_get_tag_int(tiff, tag_index, &work))
	*gps_ifd_offset = work;
      break;
    }
  }

  copy_string_tags(im, tiff, ifd0_string_tags, ifd0_string_tag_count);
  copy_int_tags(im, tiff, ifd0_int_tags, ifd0_int_tag_count);
  copy_rat_tags(im, tiff, ifd0_rat_tags, ARRAY_COUNT(ifd0_rat_tags));
  copy_name_tags(im, tiff, ifd0_values, ARRAY_COUNT(ifd0_values));
  /* copy_num_array_tags(im, tiff, ifd0_num_arrays, ARRAY_COUNT(ifd0_num_arrays)); */
}

/*
=item save_exif_ifd_tags

save_exif_ifd_tags(im, tiff)

Scans the currently loaded IFD for the tags expected in the EXIF IFD
and sets them as tags in the image.

=cut

*/

static tag_map exif_ifd_string_tags[] =
  {
    { tag_exif_version, "exif_version", },
    { tag_flashpix_version, "exif_flashpix_version", },
    { tag_related_sound_file, "exif_related_sound_file", },
    { tag_date_time_original, "exif_date_time_original", },
    { tag_date_time_digitized, "exif_date_time_digitized", },
    { tag_sub_sec_time, "exif_sub_sec_time" },
    { tag_sub_sec_time_original, "exif_sub_sec_time_original" },
    { tag_sub_sec_time_digitized, "exif_sub_sec_time_digitized" },
    { tag_image_unique_id, "exif_image_unique_id" },
    { tag_spectral_sensitivity, "exif_spectral_sensitivity" },
  };

static const int exif_ifd_string_tag_count = ARRAY_COUNT(exif_ifd_string_tags);

static tag_map exif_ifd_int_tags[] =
  {
    { tag_color_space, "exif_color_space" },
    { tag_exposure_program, "exif_exposure_program" },
    { tag_metering_mode, "exif_metering_mode" },
    { tag_light_source, "exif_light_source" },
    { tag_flash, "exif_flash" },
    { tag_focal_plane_resolution_unit, "exif_focal_plane_resolution_unit" },
    { tag_subject_location, "exif_subject_location" },
    { tag_sensing_method, "exif_sensing_method" },
    { tag_custom_rendered, "exif_custom_rendered" },
    { tag_exposure_mode, "exif_exposure_mode" },
    { tag_white_balance, "exif_white_balance" },
    { tag_focal_length_in_35mm_film, "exif_focal_length_in_35mm_film" },
    { tag_scene_capture_type, "exif_scene_capture_type" },
    { tag_contrast, "exif_contrast" },
    { tag_saturation, "exif_saturation" },
    { tag_sharpness, "exif_sharpness" },
    { tag_subject_distance_range, "exif_subject_distance_range" },
  };


static const int exif_ifd_int_tag_count = ARRAY_COUNT(exif_ifd_int_tags);

static tag_map exif_ifd_rat_tags[] =
  {
    { tag_exposure_time, "exif_exposure_time" },
    { tag_f_number, "exif_f_number" },
    { tag_shutter_speed, "exif_shutter_speed" },
    { tag_aperture, "exif_aperture" },
    { tag_brightness, "exif_brightness" },
    { tag_exposure_bias, "exif_exposure_bias" },
    { tag_max_aperture, "exif_max_aperture" },
    { tag_subject_distance, "exif_subject_distance" },
    { tag_focal_length, "exif_focal_length" },
    { tag_flash_energy, "exif_flash_energy" },
    { tag_focal_plane_x_resolution, "exif_focal_plane_x_resolution" },
    { tag_focal_plane_y_resolution, "exif_focal_plane_y_resolution" },
    { tag_exposure_index, "exif_exposure_index" },
    { tag_digital_zoom_ratio, "exif_digital_zoom_ratio" },
    { tag_gain_control, "exif_gain_control" },
  };

static const int exif_ifd_rat_tag_count = ARRAY_COUNT(exif_ifd_rat_tags);

static tag_map exposure_mode_values[] =
  {
    { 0, "Auto exposure" },
    { 1, "Manual exposure" },
    { 2, "Auto bracket" },
  };
static tag_map color_space_values[] =
  {
    { 1, "sRGB" },
    { 0xFFFF, "Uncalibrated" },
  };

static tag_map exposure_program_values[] =
  {
    { 0, "Not defined" },
    { 1, "Manual" },
    { 2, "Normal program" },
    { 3, "Aperture priority" },
    { 4, "Shutter priority" },
    { 5, "Creative program" },
    { 6, "Action program" },
    { 7, "Portrait mode" },
    { 8, "Landscape mode" },
  };

static tag_map metering_mode_values[] =
  {
    { 0, "unknown" },
    { 1, "Average" },
    { 2, "CenterWeightedAverage" },
    { 3, "Spot" },
    { 4, "MultiSpot" },
    { 5, "Pattern" },
    { 6, "Partial" },
    { 255, "other" },
  };

static tag_map light_source_values[] =
  {
    { 0, "unknown" },
    { 1, "Daylight" },
    { 2, "Fluorescent" },
    { 3, "Tungsten (incandescent light)" },
    { 4, "Flash" },
    { 9, "Fine weather" },
    { 10, "Cloudy weather" },
    { 11, "Shade" },
Commit	Line	Data
f7450478 TC	1	#include "imexif.h"
	2	#include <stdlib.h>
	3	#include <float.h>
	4
	5	/*
	6	=head1 NAME
	7
	8	imexif.c - EXIF support for Imager
	9
	10	=head1 SYNOPSIS
	11
	12	if (i_int_decode_exif(im, app1data, app1datasize)) {
	13	// exif block seen
	14	}
	15
	16	=head1 DESCRIPTION
	17
	18	This code provides a basic EXIF data decoder. It is intended to be
	19	called from the JPEG reader code when an APP1 data block is found, and
	20	will set tags in the supplied image.
	21
	22	=cut
	23	*/
	24
	25	typedef enum tiff_type_tag {
	26	tt_intel = 'I',
	27	tt_motorola = 'M'
	28	} tiff_type;
	29
	30	typedef enum {
	31	ift_byte = 1,
	32	ift_ascii = 2,
	33	ift_short = 3,
	34	ift_long = 4,
	35	ift_rational = 5,
	36	ift_sbyte = 6,
	37	ift_undefined = 7,
	38	ift_sshort = 8,
	39	ift_slong = 9,
	40	ift_srational = 10,
	41	ift_float = 11,
	42	ift_double = 12,
	43	ift_last = 12 /* keep the same as the highest type code */
	44	} ifd_entry_type;
	45
	46	static int type_sizes[] =
	47	{
	48	0, /* not used */
	49	1, /* byte */
	50	1, /* ascii */
	51	2, /* short */
	52	4, /* long */
	53	8, /* rational */
	54	1, /* sbyte */
	55	1, /* undefined */
	56	2, /* sshort */
	57	4, /* slong */
	58	8, /* srational */
	59	4, /* float */
	60	8, /* double */
	61	};
	62
	63	typedef struct {
	64	int tag;
65	int type;
66	int count;
59957854	67	int item_size;
f7450478 TC	68	int size;
	69	int offset;
	70	} ifd_entry;
	71
	72	typedef struct {
	73	int tag;
	74	char const *name;
	75	} tag_map;
	76
	77	typedef struct {
	78	int tag;
	79	char const *name;
	80	tag_map const *map;
	81	int map_count;
	82	} tag_value_map;
	83
	84	#define PASTE(left, right) PASTE_(left, right)
	85	#define PASTE_(left, right) left##right
	86	#define QUOTE(value) #value
	87
	88	#define VALUE_MAP_ENTRY(name) \
	89	{ \
	90	PASTE(tag_, name), \
	91	"exif_" QUOTE(name) "_name", \
	92	PASTE(name, _values), \
	93	ARRAY_COUNT(PASTE(name, _values)) \
	94	}
	95
	96	/* we don't process every tag */
	97	#define tag_make 271
	98	#define tag_model 272
	99	#define tag_orientation 274
	100	#define tag_x_resolution 282
	101	#define tag_y_resolution 283
	102	#define tag_resolution_unit 296
	103	#define tag_copyright 33432
	104	#define tag_software 305
	105	#define tag_artist 315
	106	#define tag_date_time 306
	107	#define tag_image_description 270
	108
	109	#define tag_exif_ifd 34665
	110	#define tag_gps_ifd 34853
	111
	112	#define resunit_none 1
	113	#define resunit_inch 2
	114	#define resunit_centimeter 3
	115
	116	/* tags from the EXIF ifd */
	117	#define tag_exif_version 0x9000
	118	#define tag_flashpix_version 0xA000
	119	#define tag_color_space 0xA001
	120	#define tag_component_configuration 0x9101
	121	#define tag_component_bits_per_pixel 0x9102
	122	#define tag_pixel_x_dimension 0xA002
	123	#define tag_pixel_y_dimension 0xA003
	124	#define tag_maker_note 0x927C
	125	#define tag_user_comment 0x9286
	126	#define tag_related_sound_file 0xA004
	127	#define tag_date_time_original 0x9003
	128	#define tag_date_time_digitized 0x9004
	129	#define tag_sub_sec_time 0x9290
	130	#define tag_sub_sec_time_original 0x9291
	131	#define tag_sub_sec_time_digitized 0x9292
132	#define tag_image_unique_id 0xA420
133	#define tag_exposure_time 0x829a
134	#define tag_f_number 0x829D
135	#define tag_exposure_program 0x8822
136	#define tag_spectral_sensitivity 0x8824
59957854	137	#define tag_iso_speed_ratings 0x8827
f7450478 TC	138	#define tag_oecf 0x8828
	139	#define tag_shutter_speed 0x9201
	140	#define tag_aperture 0x9202
	141	#define tag_brightness 0x9203
	142	#define tag_exposure_bias 0x9204
	143	#define tag_max_aperture 0x9205
	144	#define tag_subject_distance 0x9206
	145	#define tag_metering_mode 0x9207
	146	#define tag_light_source 0x9208
	147	#define tag_flash 0x9209
	148	#define tag_focal_length 0x920a
	149	#define tag_subject_area 0x9214
	150	#define tag_flash_energy 0xA20B
	151	#define tag_spatial_frequency_response 0xA20C
	152	#define tag_focal_plane_x_resolution 0xA20e
	153	#define tag_focal_plane_y_resolution 0xA20F
	154	#define tag_focal_plane_resolution_unit 0xA210
	155	#define tag_subject_location 0xA214
	156	#define tag_exposure_index 0xA215
	157	#define tag_sensing_method 0xA217
	158	#define tag_file_source 0xA300
	159	#define tag_scene_type 0xA301
	160	#define tag_cfa_pattern 0xA302
	161	#define tag_custom_rendered 0xA401
	162	#define tag_exposure_mode 0xA402
	163	#define tag_white_balance 0xA403
	164	#define tag_digital_zoom_ratio 0xA404
	165	#define tag_focal_length_in_35mm_film 0xA405
	166	#define tag_scene_capture_type 0xA406
	167	#define tag_gain_control 0xA407
	168	#define tag_contrast 0xA408
	169	#define tag_saturation 0xA409
	170	#define tag_sharpness 0xA40A
	171	#define tag_device_setting_description 0xA40B
	172	#define tag_subject_distance_range 0xA40C
	173
59957854 TC	174	/* GPS tags */
	175	#define tag_gps_version_id 0
	176	#define tag_gps_latitude_ref 1
	177	#define tag_gps_latitude 2
	178	#define tag_gps_longitude_ref 3
	179	#define tag_gps_longitude 4
	180	#define tag_gps_altitude_ref 5
	181	#define tag_gps_altitude 6
	182	#define tag_gps_time_stamp 7
	183	#define tag_gps_satellites 8
	184	#define tag_gps_status 9
	185	#define tag_gps_measure_mode 10
	186	#define tag_gps_dop 11
	187	#define tag_gps_speed_ref 12
	188	#define tag_gps_speed 13
	189	#define tag_gps_track_ref 14
	190	#define tag_gps_track 15
	191	#define tag_gps_img_direction_ref 16
	192	#define tag_gps_img_direction 17
	193	#define tag_gps_map_datum 18
	194	#define tag_gps_dest_latitude_ref 19
	195	#define tag_gps_dest_latitude 20
	196	#define tag_gps_dest_longitude_ref 21
	197	#define tag_gps_dest_longitude 22
	198	#define tag_gps_dest_bearing_ref 23
	199	#define tag_gps_dest_bearing 24
	200	#define tag_gps_dest_distance_ref 25
	201	#define tag_gps_dest_distance 26
	202	#define tag_gps_processing_method 27
	203	#define tag_gps_area_information 28
	204	#define tag_gps_date_stamp 29
	205	#define tag_gps_differential 30
	206
f7450478 TC	207	/* don't use this on pointers */
	208	#define ARRAY_COUNT(array) (sizeof(array)/sizeof(*array))
	209
	210	/* in memory tiff structure */
	211	typedef struct {
	212	/* the data we use as a tiff */
	213	unsigned char *base;
	214	size_t size;
	215
	216	/* intel or motorola byte order */
	217	tiff_type type;
	218
	219	/* initial ifd offset */
	220	unsigned long first_ifd_offset;
	221
	222	/* size (in entries) and data */
	223	int ifd_size;
	224	ifd_entry *ifd;
	225	unsigned long next_ifd;
	226	} imtiff;
	227
	228	static int tiff_init(imtiff tiff, unsigned char base, size_t length);
	229	static int tiff_load_ifd(imtiff *tiff, unsigned long offset);
	230	static void tiff_final(imtiff *tiff);
	231	static void tiff_clear_ifd(imtiff *tiff);
e4bf9335	232	#if 0 /* currently unused, but that may change */
f7450478 TC	233	static int tiff_get_bytes(imtiff tiff, unsigned char to, size_t offset,
f7450478 TC	234	size_t count);
e4bf9335	235	#endif
f7450478 TC	236	static int tiff_get_tag_double(imtiff , int index, double result);
	237	static int tiff_get_tag_int(imtiff , int index, int result);
	238	static unsigned tiff_get16(imtiff *, unsigned long offset);
	239	static unsigned tiff_get32(imtiff *, unsigned long offset);
	240	static int tiff_get16s(imtiff *, unsigned long offset);
	241	static int tiff_get32s(imtiff *, unsigned long offset);
	242	static double tiff_get_rat(imtiff *, unsigned long offset);
	243	static double tiff_get_rats(imtiff *, unsigned long offset);
59957854	244	static void save_ifd0_tags(i_img im, imtiff tiff, unsigned long exif_ifd_offset, unsigned long gps_ifd_offset);
f7450478	245	static void save_exif_ifd_tags(i_img im, imtiff tiff);
59957854	246	static void save_gps_ifd_tags(i_img im, imtiff tiff);
f7450478 TC	247	static void
	248	copy_string_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
	249	static void
	250	copy_int_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
	251	static void
	252	copy_rat_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
	253	static void
59957854 TC	254	copy_num_array_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
59957854 TC	255	static void
f7450478 TC	256	copy_name_tags(i_img im, imtiff tiff, tag_value_map *map, int map_count);
	257	static void process_maker_note(i_img im, imtiff tiff, unsigned long offset, size_t size);
	258
	259	/*
	260	=head1 PUBLIC FUNCTIONS
	261
	262	These functions are available to other parts of Imager. They aren't
	263	intended to be called from outside of Imager.
	264
	265	=over
	266
	267	=item i_int_decode_exit
	268
	269	i_int_decode_exif(im, data_base, data_size);
	270
	271	The data from data_base for data_size bytes will be scanned for EXIF
	272	data.
	273
	274	Any data found will be used to set tags in the supplied image.
	275
	276	The intent is that invalid EXIF data will simply fail to set tags, and
	277	write to the log. In no case should this code exit when supplied
	278	invalid data.
	279
	280	Returns true if an Exif header was seen.
	281
	282	*/
	283
	284	int
	285	i_int_decode_exif(i_img im, unsigned char data, size_t length) {
	286	imtiff tiff;
	287	unsigned long exif_ifd_offset = 0;
59957854	288	unsigned long gps_ifd_offset = 0;
f7450478 TC	289	/* basic checks - must start with "Exif\0\0" */
	290
	291	if (length < 6 \|\| memcmp(data, "Exif\0\0", 6) != 0) {
	292	return 0;
	293	}
	294
	295	data += 6;
	296	length -= 6;
	297
	298	if (!tiff_init(&tiff, data, length)) {
	299	mm_log((2, "Exif header found, but no valid TIFF header\n"));
	300	return 1;
	301	}
	302	if (!tiff_load_ifd(&tiff, tiff.first_ifd_offset)) {
	303	mm_log((2, "Exif header found, but could not load IFD 0\n"));
	304	tiff_final(&tiff);
	305	return 1;
	306	}
	307
59957854	308	save_ifd0_tags(im, &tiff, &exif_ifd_offset, &gps_ifd_offset);
f7450478 TC	309
	310	if (exif_ifd_offset) {
	311	if (tiff_load_ifd(&tiff, exif_ifd_offset)) {
	312	save_exif_ifd_tags(im, &tiff);
	313	}
	314	else {
	315	mm_log((2, "Could not load Exif IFD\n"));
	316	}
	317	}
	318
59957854 TC	319	if (gps_ifd_offset) {
	320	if (tiff_load_ifd(&tiff, gps_ifd_offset)) {
	321	save_gps_ifd_tags(im, &tiff);
	322	}
	323	else {
	324	mm_log((2, "Could not load GPS IFD\n"));
	325	}
	326	}
	327
f7450478 TC	328	tiff_final(&tiff);
	329
	330	return 1;
	331	}
	332
	333	/*
	334
	335	=back
	336
	337	=head1 INTERNAL FUNCTIONS
	338
	339	=head2 EXIF Processing
	340
	341	=over
	342
	343	=item save_ifd0_tags
	344
59957854	345	save_ifd0_tags(im, tiff, &exif_ifd_offset, &gps_ifd_offset)
f7450478 TC	346
	347	Scans the currently loaded IFD for tags expected in IFD0 and sets them
	348	in the image.
	349
	350	Sets *exif_ifd_offset to the offset of the EXIF IFD if found.
	351
	352	=cut
	353
	354	*/
	355
	356	static tag_map ifd0_string_tags[] =
	357	{
af070d99 TC	358	{ tag_make, "exif_make" },
	359	{ tag_model, "exif_model" },
	360	{ tag_copyright, "exif_copyright" },
	361	{ tag_software, "exif_software" },
	362	{ tag_artist, "exif_artist" },
	363	{ tag_date_time, "exif_date_time" },
	364	{ tag_image_description, "exif_image_description" },
f7450478 TC	365	};
	366
	367	static const int ifd0_string_tag_count = ARRAY_COUNT(ifd0_string_tags);
	368
	369	static tag_map ifd0_int_tags[] =
	370	{
	371	{ tag_orientation, "exif_orientation", },
	372	{ tag_resolution_unit, "exif_resolution_unit" },
	373	};
	374
	375	static const int ifd0_int_tag_count = ARRAY_COUNT(ifd0_int_tags);
	376
	377	static tag_map ifd0_rat_tags[] =
	378	{
	379	{ tag_x_resolution, "exif_x_resolution" },
	380	{ tag_y_resolution, "exif_y_resolution" },
	381	};
	382
	383	static tag_map resolution_unit_values[] =
	384	{
	385	{ 1, "none" },
	386	{ 2, "inches" },
	387	{ 3, "centimeters" },
	388	};
	389
	390	static tag_value_map ifd0_values[] =
	391	{
	392	VALUE_MAP_ENTRY(resolution_unit),
	393	};
	394
	395	static void
59957854 TC	396	save_ifd0_tags(i_img im, imtiff tiff, unsigned long *exif_ifd_offset,
59957854 TC	397	unsigned long *gps_ifd_offset) {
af070d99	398	int tag_index;
f7450478 TC	399	int work;
	400	ifd_entry *entry;
	401
	402	for (tag_index = 0, entry = tiff->ifd;
	403	tag_index < tiff->ifd_size; ++tag_index, ++entry) {
	404	switch (entry->tag) {
	405	case tag_exif_ifd:
	406	if (tiff_get_tag_int(tiff, tag_index, &work))
	407	*exif_ifd_offset = work;
	408	break;
59957854 TC	409
	410	case tag_gps_ifd:
	411	if (tiff_get_tag_int(tiff, tag_index, &work))
	412	*gps_ifd_offset = work;
	413	break;
f7450478 TC	414	}
	415	}
	416
	417	copy_string_tags(im, tiff, ifd0_string_tags, ifd0_string_tag_count);
	418	copy_int_tags(im, tiff, ifd0_int_tags, ifd0_int_tag_count);
	419	copy_rat_tags(im, tiff, ifd0_rat_tags, ARRAY_COUNT(ifd0_rat_tags));
	420	copy_name_tags(im, tiff, ifd0_values, ARRAY_COUNT(ifd0_values));
59957854	421	/* copy_num_array_tags(im, tiff, ifd0_num_arrays, ARRAY_COUNT(ifd0_num_arrays)); */
f7450478 TC	422	}
	423
	424	/*
	425	=item save_exif_ifd_tags
	426
	427	save_exif_ifd_tags(im, tiff)
	428
	429	Scans the currently loaded IFD for the tags expected in the EXIF IFD
	430	and sets them as tags in the image.
	431
	432	=cut
	433
	434	*/
	435
	436	static tag_map exif_ifd_string_tags[] =
	437	{
	438	{ tag_exif_version, "exif_version", },
	439	{ tag_flashpix_version, "exif_flashpix_version", },
	440	{ tag_related_sound_file, "exif_related_sound_file", },
	441	{ tag_date_time_original, "exif_date_time_original", },
	442	{ tag_date_time_digitized, "exif_date_time_digitized", },
	443	{ tag_sub_sec_time, "exif_sub_sec_time" },
	444	{ tag_sub_sec_time_original, "exif_sub_sec_time_original" },
	445	{ tag_sub_sec_time_digitized, "exif_sub_sec_time_digitized" },
	446	{ tag_image_unique_id, "exif_image_unique_id" },
	447	{ tag_spectral_sensitivity, "exif_spectral_sensitivity" },
	448	};
	449
	450	static const int exif_ifd_string_tag_count = ARRAY_COUNT(exif_ifd_string_tags);
	451
	452	static tag_map exif_ifd_int_tags[] =
	453	{
	454	{ tag_color_space, "exif_color_space" },
	455	{ tag_exposure_program, "exif_exposure_program" },
f7450478 TC	456	{ tag_metering_mode, "exif_metering_mode" },
	457	{ tag_light_source, "exif_light_source" },
	458	{ tag_flash, "exif_flash" },
	459	{ tag_focal_plane_resolution_unit, "exif_focal_plane_resolution_unit" },
	460	{ tag_subject_location, "exif_subject_location" },
	461	{ tag_sensing_method, "exif_sensing_method" },
	462	{ tag_custom_rendered, "exif_custom_rendered" },
	463	{ tag_exposure_mode, "exif_exposure_mode" },
	464	{ tag_white_balance, "exif_white_balance" },
	465	{ tag_focal_length_in_35mm_film, "exif_focal_length_in_35mm_film" },
	466	{ tag_scene_capture_type, "exif_scene_capture_type" },
	467	{ tag_contrast, "exif_contrast" },
	468	{ tag_saturation, "exif_saturation" },
	469	{ tag_sharpness, "exif_sharpness" },
	470	{ tag_subject_distance_range, "exif_subject_distance_range" },
	471	};
	472
	473
	474	static const int exif_ifd_int_tag_count = ARRAY_COUNT(exif_ifd_int_tags);
	475
	476	static tag_map exif_ifd_rat_tags[] =
	477	{
	478	{ tag_exposure_time, "exif_exposure_time" },
	479	{ tag_f_number, "exif_f_number" },
	480	{ tag_shutter_speed, "exif_shutter_speed" },
	481	{ tag_aperture, "exif_aperture" },
	482	{ tag_brightness, "exif_brightness" },
	483	{ tag_exposure_bias, "exif_exposure_bias" },
	484	{ tag_max_aperture, "exif_max_aperture" },
	485	{ tag_subject_distance, "exif_subject_distance" },
	486	{ tag_focal_length, "exif_focal_length" },
	487	{ tag_flash_energy, "exif_flash_energy" },
	488	{ tag_focal_plane_x_resolution, "exif_focal_plane_x_resolution" },
	489	{ tag_focal_plane_y_resolution, "exif_focal_plane_y_resolution" },
	490	{ tag_exposure_index, "exif_exposure_index" },
	491	{ tag_digital_zoom_ratio, "exif_digital_zoom_ratio" },
	492	{ tag_gain_control, "exif_gain_control" },
	493	};
	494
	495	static const int exif_ifd_rat_tag_count = ARRAY_COUNT(exif_ifd_rat_tags);
	496
	497	static tag_map exposure_mode_values[] =
	498	{
	499	{ 0, "Auto exposure" },
	500	{ 1, "Manual exposure" },
	501	{ 2, "Auto bracket" },
	502	};
	503	static tag_map color_space_values[] =
	504	{
	505	{ 1, "sRGB" },
	506	{ 0xFFFF, "Uncalibrated" },
	507	};
	508
	509	static tag_map exposure_program_values[] =
	510	{
	511	{ 0, "Not defined" },
	512	{ 1, "Manual" },
	513	{ 2, "Normal program" },
	514	{ 3, "Aperture priority" },
	515	{ 4, "Shutter priority" },
	516	{ 5, "Creative program" },
	517	{ 6, "Action program" },
	518	{ 7, "Portrait mode" },
	519	{ 8, "Landscape mode" },
520	};
521
522	static tag_map metering_mode_values[] =
523	{
524	{ 0, "unknown" },
525	{ 1, "Average" },
526	{ 2, "CenterWeightedAverage" },
527	{ 3, "Spot" },
528	{ 4, "MultiSpot" },
529	{ 5, "Pattern" },
530	{ 6, "Partial" },
531	{ 255, "other" },
532	};
533
534	static tag_map light_source_values[] =
535	{
536	{ 0, "unknown" },
537	{ 1, "Daylight" },
538	{ 2, "Fluorescent" },
539	{ 3, "Tungsten (incandescent light)" },
540	{ 4, "Flash" },
541	{ 9, "Fine weather" },
542	{ 10, "Cloudy weather" },
543	{ 11, "Shade" },
544