[imager.git] / imexif.c

#include "imager.h"
#include "imexif.h"
#include <stdlib.h>
#include <float.h>
#include <string.h>
#include <stdio.h>

/*
=head1 NAME

imexif.c - EXIF support for Imager

=head1 SYNOPSIS

  if (im_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 */
  const 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, const 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 im_decode_exif

im_decode_exif(im, data_base, data_size);

The data from C<data_base> for C<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.

=cut
*/

int
im_decode_exif(i_img *im, const unsigned char *data, size_t length) {
  imtiff tiff;
  unsigned long exif_ifd_offset = 0;
  unsigned long gps_ifd_offset = 0;

  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
75e155e1	1	#include "imager.h"
f7450478 TC	2	#include "imexif.h"
	3	#include <stdlib.h>
	4	#include <float.h>
797a9f9c	5	#include <string.h>
8d14daab	6	#include <stdio.h>
f7450478 TC	7
	8	/*
	9	=head1 NAME
	10
	11	imexif.c - EXIF support for Imager
	12
	13	=head1 SYNOPSIS
	14
75e155e1	15	if (im_decode_exif(im, app1data, app1datasize)) {
f7450478 TC	16	// exif block seen
	17	}
	18
	19	=head1 DESCRIPTION
	20
	21	This code provides a basic EXIF data decoder. It is intended to be
	22	called from the JPEG reader code when an APP1 data block is found, and
	23	will set tags in the supplied image.
	24
	25	=cut
	26	*/
	27
	28	typedef enum tiff_type_tag {
	29	tt_intel = 'I',
	30	tt_motorola = 'M'
	31	} tiff_type;
	32
	33	typedef enum {
	34	ift_byte = 1,
	35	ift_ascii = 2,
	36	ift_short = 3,
	37	ift_long = 4,
	38	ift_rational = 5,
	39	ift_sbyte = 6,
	40	ift_undefined = 7,
	41	ift_sshort = 8,
	42	ift_slong = 9,
	43	ift_srational = 10,
	44	ift_float = 11,
	45	ift_double = 12,
	46	ift_last = 12 /* keep the same as the highest type code */
	47	} ifd_entry_type;
	48
	49	static int type_sizes[] =
	50	{
	51	0, /* not used */
	52	1, /* byte */
	53	1, /* ascii */
	54	2, /* short */
	55	4, /* long */
	56	8, /* rational */
	57	1, /* sbyte */
	58	1, /* undefined */
	59	2, /* sshort */
	60	4, /* slong */
	61	8, /* srational */
	62	4, /* float */
	63	8, /* double */
	64	};
	65
	66	typedef struct {
	67	int tag;
	68	int type;
	69	int count;
59957854	70	int item_size;
f7450478 TC	71	int size;
	72	int offset;
	73	} ifd_entry;
	74
	75	typedef struct {
	76	int tag;
	77	char const *name;
	78	} tag_map;
	79
	80	typedef struct {
	81	int tag;
	82	char const *name;
	83	tag_map const *map;
	84	int map_count;
	85	} tag_value_map;
	86
	87	#define PASTE(left, right) PASTE_(left, right)
	88	#define PASTE_(left, right) left##right
	89	#define QUOTE(value) #value
	90
	91	#define VALUE_MAP_ENTRY(name) \
	92	{ \
	93	PASTE(tag_, name), \
	94	"exif_" QUOTE(name) "_name", \
	95	PASTE(name, _values), \
	96	ARRAY_COUNT(PASTE(name, _values)) \
	97	}
	98
	99	/* we don't process every tag */
	100	#define tag_make 271
	101	#define tag_model 272
	102	#define tag_orientation 274
	103	#define tag_x_resolution 282
	104	#define tag_y_resolution 283
	105	#define tag_resolution_unit 296
	106	#define tag_copyright 33432
	107	#define tag_software 305
	108	#define tag_artist 315
	109	#define tag_date_time 306
	110	#define tag_image_description 270
	111
	112	#define tag_exif_ifd 34665
	113	#define tag_gps_ifd 34853
	114
	115	#define resunit_none 1
	116	#define resunit_inch 2
	117	#define resunit_centimeter 3
	118
	119	/* tags from the EXIF ifd */
	120	#define tag_exif_version 0x9000
	121	#define tag_flashpix_version 0xA000
	122	#define tag_color_space 0xA001
	123	#define tag_component_configuration 0x9101
	124	#define tag_component_bits_per_pixel 0x9102
	125	#define tag_pixel_x_dimension 0xA002
	126	#define tag_pixel_y_dimension 0xA003
	127	#define tag_maker_note 0x927C
	128	#define tag_user_comment 0x9286
	129	#define tag_related_sound_file 0xA004
	130	#define tag_date_time_original 0x9003
	131	#define tag_date_time_digitized 0x9004
	132	#define tag_sub_sec_time 0x9290
	133	#define tag_sub_sec_time_original 0x9291
	134	#define tag_sub_sec_time_digitized 0x9292
135	#define tag_image_unique_id 0xA420
136	#define tag_exposure_time 0x829a
137	#define tag_f_number 0x829D
138	#define tag_exposure_program 0x8822
139	#define tag_spectral_sensitivity 0x8824
59957854	140	#define tag_iso_speed_ratings 0x8827
f7450478 TC	141	#define tag_oecf 0x8828
	142	#define tag_shutter_speed 0x9201
	143	#define tag_aperture 0x9202
	144	#define tag_brightness 0x9203
	145	#define tag_exposure_bias 0x9204
	146	#define tag_max_aperture 0x9205
	147	#define tag_subject_distance 0x9206
	148	#define tag_metering_mode 0x9207
	149	#define tag_light_source 0x9208
	150	#define tag_flash 0x9209
	151	#define tag_focal_length 0x920a
	152	#define tag_subject_area 0x9214
	153	#define tag_flash_energy 0xA20B
	154	#define tag_spatial_frequency_response 0xA20C
	155	#define tag_focal_plane_x_resolution 0xA20e
	156	#define tag_focal_plane_y_resolution 0xA20F
	157	#define tag_focal_plane_resolution_unit 0xA210
	158	#define tag_subject_location 0xA214
	159	#define tag_exposure_index 0xA215
	160	#define tag_sensing_method 0xA217
	161	#define tag_file_source 0xA300
	162	#define tag_scene_type 0xA301
	163	#define tag_cfa_pattern 0xA302
	164	#define tag_custom_rendered 0xA401
	165	#define tag_exposure_mode 0xA402
	166	#define tag_white_balance 0xA403
	167	#define tag_digital_zoom_ratio 0xA404
	168	#define tag_focal_length_in_35mm_film 0xA405
	169	#define tag_scene_capture_type 0xA406
	170	#define tag_gain_control 0xA407
	171	#define tag_contrast 0xA408
	172	#define tag_saturation 0xA409
	173	#define tag_sharpness 0xA40A
	174	#define tag_device_setting_description 0xA40B
	175	#define tag_subject_distance_range 0xA40C
	176
59957854 TC	177	/* GPS tags */
	178	#define tag_gps_version_id 0
	179	#define tag_gps_latitude_ref 1
	180	#define tag_gps_latitude 2
	181	#define tag_gps_longitude_ref 3
	182	#define tag_gps_longitude 4
	183	#define tag_gps_altitude_ref 5
	184	#define tag_gps_altitude 6
	185	#define tag_gps_time_stamp 7
	186	#define tag_gps_satellites 8
	187	#define tag_gps_status 9
	188	#define tag_gps_measure_mode 10
	189	#define tag_gps_dop 11
	190	#define tag_gps_speed_ref 12
	191	#define tag_gps_speed 13
	192	#define tag_gps_track_ref 14
	193	#define tag_gps_track 15
	194	#define tag_gps_img_direction_ref 16
	195	#define tag_gps_img_direction 17
	196	#define tag_gps_map_datum 18
	197	#define tag_gps_dest_latitude_ref 19
	198	#define tag_gps_dest_latitude 20
	199	#define tag_gps_dest_longitude_ref 21
	200	#define tag_gps_dest_longitude 22
	201	#define tag_gps_dest_bearing_ref 23
	202	#define tag_gps_dest_bearing 24
	203	#define tag_gps_dest_distance_ref 25
	204	#define tag_gps_dest_distance 26
	205	#define tag_gps_processing_method 27
	206	#define tag_gps_area_information 28
	207	#define tag_gps_date_stamp 29
	208	#define tag_gps_differential 30
	209
f7450478 TC	210	/* don't use this on pointers */
	211	#define ARRAY_COUNT(array) (sizeof(array)/sizeof(*array))
	212
	213	/* in memory tiff structure */
	214	typedef struct {
	215	/* the data we use as a tiff */
0b365b7f	216	const unsigned char *base;
f7450478 TC	217	size_t size;
	218
	219	/* intel or motorola byte order */
	220	tiff_type type;
	221
	222	/* initial ifd offset */
	223	unsigned long first_ifd_offset;
	224
	225	/* size (in entries) and data */
	226	int ifd_size;
	227	ifd_entry *ifd;
	228	unsigned long next_ifd;
	229	} imtiff;
	230
0b365b7f	231	static int tiff_init(imtiff tiff, const unsigned char base, size_t length);
f7450478 TC	232	static int tiff_load_ifd(imtiff *tiff, unsigned long offset);
	233	static void tiff_final(imtiff *tiff);
	234	static void tiff_clear_ifd(imtiff *tiff);
e4bf9335	235	#if 0 /* currently unused, but that may change */
f7450478 TC	236	static int tiff_get_bytes(imtiff tiff, unsigned char to, size_t offset,
f7450478 TC	237	size_t count);
e4bf9335	238	#endif
f7450478 TC	239	static int tiff_get_tag_double(imtiff , int index, double result);
	240	static int tiff_get_tag_int(imtiff , int index, int result);
	241	static unsigned tiff_get16(imtiff *, unsigned long offset);
	242	static unsigned tiff_get32(imtiff *, unsigned long offset);
	243	static int tiff_get16s(imtiff *, unsigned long offset);
	244	static int tiff_get32s(imtiff *, unsigned long offset);
	245	static double tiff_get_rat(imtiff *, unsigned long offset);
	246	static double tiff_get_rats(imtiff *, unsigned long offset);
59957854	247	static void save_ifd0_tags(i_img im, imtiff tiff, unsigned long exif_ifd_offset, unsigned long gps_ifd_offset);
f7450478	248	static void save_exif_ifd_tags(i_img im, imtiff tiff);
59957854	249	static void save_gps_ifd_tags(i_img im, imtiff tiff);
f7450478 TC	250	static void
	251	copy_string_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
	252	static void
	253	copy_int_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
	254	static void
	255	copy_rat_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
	256	static void
59957854 TC	257	copy_num_array_tags(i_img im, imtiff tiff, tag_map *map, int map_count);
59957854 TC	258	static void
f7450478 TC	259	copy_name_tags(i_img im, imtiff tiff, tag_value_map *map, int map_count);
	260	static void process_maker_note(i_img im, imtiff tiff, unsigned long offset, size_t size);
	261
	262	/*
	263	=head1 PUBLIC FUNCTIONS
	264
	265	These functions are available to other parts of Imager. They aren't
	266	intended to be called from outside of Imager.
	267
	268	=over
	269
75e155e1	270	=item im_decode_exif
f7450478	271
75e155e1	272	im_decode_exif(im, data_base, data_size);
f7450478	273
75e155e1 TC	274	The data from C<data_base> for C<data_size> bytes will be scanned for
75e155e1 TC	275	EXIF data.
f7450478 TC	276
	277	Any data found will be used to set tags in the supplied image.
	278
	279	The intent is that invalid EXIF data will simply fail to set tags, and
	280	write to the log. In no case should this code exit when supplied
	281	invalid data.
	282
75e155e1	283	Returns true if an EXIF header was seen.
f7450478	284
12db268a	285	=cut
f7450478 TC	286	*/
	287
	288	int
0b365b7f	289	im_decode_exif(i_img im, const unsigned char data, size_t length) {
f7450478 TC	290	imtiff tiff;
f7450478 TC	291	unsigned long exif_ifd_offset = 0;
59957854	292	unsigned long gps_ifd_offset = 0;
f7450478 TC	293
	294	if (!tiff_init(&tiff, data, length)) {
	295	mm_log((2, "Exif header found, but no valid TIFF header\n"));
	296	return 1;
	297	}
	298	if (!tiff_load_ifd(&tiff, tiff.first_ifd_offset)) {
	299	mm_log((2, "Exif header found, but could not load IFD 0\n"));
	300	tiff_final(&tiff);
	301	return 1;
	302	}
	303
59957854	304	save_ifd0_tags(im, &tiff, &exif_ifd_offset, &gps_ifd_offset);
f7450478 TC	305
	306	if (exif_ifd_offset) {
	307	if (tiff_load_ifd(&tiff, exif_ifd_offset)) {
	308	save_exif_ifd_tags(im, &tiff);
	309	}
	310	else {
	311	mm_log((2, "Could not load Exif IFD\n"));
	312	}
	313	}
	314
59957854 TC	315	if (gps_ifd_offset) {
	316	if (tiff_load_ifd(&tiff, gps_ifd_offset)) {
	317	save_gps_ifd_tags(im, &tiff);
	318	}
	319	else {
	320	mm_log((2, "Could not load GPS IFD\n"));
	321	}
	322	}
	323
f7450478 TC	324	tiff_final(&tiff);
	325
	326	return 1;
	327	}
	328
	329	/*
	330
	331	=back
	332
	333	=head1 INTERNAL FUNCTIONS
	334
	335	=head2 EXIF Processing
	336
	337	=over
	338
	339	=item save_ifd0_tags
	340
59957854	341	save_ifd0_tags(im, tiff, &exif_ifd_offset, &gps_ifd_offset)
f7450478 TC	342
	343	Scans the currently loaded IFD for tags expected in IFD0 and sets them
	344	in the image.
	345
	346	Sets *exif_ifd_offset to the offset of the EXIF IFD if found.
	347
	348	=cut
	349
	350	*/
	351
	352	static tag_map ifd0_string_tags[] =
	353	{
af070d99 TC	354	{ tag_make, "exif_make" },
	355	{ tag_model, "exif_model" },
	356	{ tag_copyright, "exif_copyright" },
	357	{ tag_software, "exif_software" },
	358	{ tag_artist, "exif_artist" },
	359	{ tag_date_time, "exif_date_time" },
	360	{ tag_image_description, "exif_image_description" },
f7450478 TC	361	};
	362
	363	static const int ifd0_string_tag_count = ARRAY_COUNT(ifd0_string_tags);
	364
	365	static tag_map ifd0_int_tags[] =
	366	{
	367	{ tag_orientation, "exif_orientation", },
	368	{ tag_resolution_unit, "exif_resolution_unit" },
	369	};
	370
	371	static const int ifd0_int_tag_count = ARRAY_COUNT(ifd0_int_tags);
	372
	373	static tag_map ifd0_rat_tags[] =
	374	{
	375	{ tag_x_resolution, "exif_x_resolution" },
	376	{ tag_y_resolution, "exif_y_resolution" },
	377	};
	378
	379	static tag_map resolution_unit_values[] =
	380	{
	381	{ 1, "none" },
	382	{ 2, "inches" },
	383	{ 3, "centimeters" },
	384	};
	385
	386	static tag_value_map ifd0_values[] =
	387	{
	388	VALUE_MAP_ENTRY(resolution_unit),
	389	};
	390
	391	static void
59957854 TC	392	save_ifd0_tags(i_img im, imtiff tiff, unsigned long *exif_ifd_offset,
59957854 TC	393	unsigned long *gps_ifd_offset) {
af070d99	394	int tag_index;
f7450478 TC	395	int work;
	396	ifd_entry *entry;
	397
	398	for (tag_index = 0, entry = tiff->ifd;
	399	tag_index < tiff->ifd_size; ++tag_index, ++entry) {
	400	switch (entry->tag) {
	401	case tag_exif_ifd:
	402	if (tiff_get_tag_int(tiff, tag_index, &work))
	403	*exif_ifd_offset = work;
	404	break;
59957854 TC	405
	406	case tag_gps_ifd:
	407	if (tiff_get_tag_int(tiff, tag_index, &work))
	408	*gps_ifd_offset = work;
	409	break;
f7450478 TC	410	}
	411	}
	412
	413	copy_string_tags(im, tiff, ifd0_string_tags, ifd0_string_tag_count);
	414	copy_int_tags(im, tiff, ifd0_int_tags, ifd0_int_tag_count);
	415	copy_rat_tags(im, tiff, ifd0_rat_tags, ARRAY_COUNT(ifd0_rat_tags));
	416	copy_name_tags(im, tiff, ifd0_values, ARRAY_COUNT(ifd0_values));
59957854	417	/* copy_num_array_tags(im, tiff, ifd0_num_arrays, ARRAY_COUNT(ifd0_num_arrays)); */
f7450478 TC	418	}
	419
	420	/*
	421	=item save_exif_ifd_tags
	422
	423	save_exif_ifd_tags(im, tiff)
	424
	425	Scans the currently loaded IFD for the tags expected in the EXIF IFD
	426	and sets them as tags in the image.
	427
	428	=cut
	429
	430	*/
	431
	432	static tag_map exif_ifd_string_tags[] =
	433	{
	434	{ tag_exif_version, "exif_version", },
	435	{ tag_flashpix_version, "exif_flashpix_version", },
	436	{ tag_related_sound_file, "exif_related_sound_file", },
	437	{ tag_date_time_original, "exif_date_time_original", },
	438	{ tag_date_time_digitized, "exif_date_time_digitized", },
	439	{ tag_sub_sec_time, "exif_sub_sec_time" },
	440	{ tag_sub_sec_time_original, "exif_sub_sec_time_original" },
	441	{ tag_sub_sec_time_digitized, "exif_sub_sec_time_digitized" },
	442	{ tag_image_unique_id, "exif_image_unique_id" },
	443	{ tag_spectral_sensitivity, "exif_spectral_sensitivity" },
	444	};
	445
	446	static const int exif_ifd_string_tag_count = ARRAY_COUNT(exif_ifd_string_tags);
	447
	448	static tag_map exif_ifd_int_tags[] =
	449	{
	450	{ tag_color_space, "exif_color_space" },
	451	{ tag_exposure_program, "exif_exposure_program" },
f7450478 TC	452	{ tag_metering_mode, "exif_metering_mode" },
	453	{ tag_light_source, "exif_light_source" },
	454	{ tag_flash, "exif_flash" },
	455	{ tag_focal_plane_resolution_unit, "exif_focal_plane_resolution_unit" },
	456	{ tag_subject_location, "exif_subject_location" },
	457	{ tag_sensing_method, "exif_sensing_method" },
	458	{ tag_custom_rendered, "exif_custom_rendered" },
	459	{ tag_exposure_mode, "exif_exposure_mode" },
	460	{ tag_white_balance, "exif_white_balance" },
	461	{ tag_focal_length_in_35mm_film, "exif_focal_length_in_35mm_film" },
	462	{ tag_scene_capture_type, "exif_scene_capture_type" },
	463	{ tag_contrast, "exif_contrast" },
	464	{ tag_saturation, "exif_saturation" },
	465	{ tag_sharpness, "exif_sharpness" },
	466	{ tag_subject_distance_range, "exif_subject_distance_range" },
	467	};
	468
	469
	470	static const int exif_ifd_int_tag_count = ARRAY_COUNT(exif_ifd_int_tags);
	471
	472	static tag_map exif_ifd_rat_tags[] =
	473	{
	474	{ tag_exposure_time, "exif_exposure_time" },
	475	{ tag_f_number, "exif_f_number" },
	476	{ tag_shutter_speed, "exif_shutter_speed" },
	477	{ tag_aperture, "exif_aperture" },
	478	{ tag_brightness, "exif_brightness" },
	479	{ tag_exposure_bias, "exif_exposure_bias" },
	480	{ tag_max_aperture, "exif_max_aperture" },
	481	{ tag_subject_distance, "exif_subject_distance" },
	482	{ tag_focal_length, "exif_focal_length" },
	483	{ tag_flash_energy, "exif_flash_energy" },
	484	{ tag_focal_plane_x_resolution, "exif_focal_plane_x_resolution" },
	485	{ tag_focal_plane_y_resolution, "exif_focal_plane_y_resolution" },
	486	{ tag_exposure_index, "exif_exposure_index" },
	487	{ tag_digital_zoom_ratio, "exif_digital_zoom_ratio" },
	488	{ tag_gain_control, "exif_gain_control" },
	489	};
	490
	491	static const int exif_ifd_rat_tag_count = ARRAY_COUNT(exif_ifd_rat_tags);
	492
	493	static tag_map exposure_mode_values[] =
	494	{
	495	{ 0, "Auto exposure" },
	496	{ 1, "Manual exposure" },
	497	{ 2, "Auto bracket" },
	498	};
	499	static tag_map color_space_values[] =
	500	{
	501	{ 1, "sRGB" },
	502	{ 0xFFFF, "Uncalibrated" },
	503	};
	504
	505	static tag_map exposure_program_values[] =
	506	{
	507	{ 0, "Not defined" },
	508	{ 1, "Manual" },
	509	{ 2, "Normal program" },
	510	{ 3, "Aperture priority" },
	511	{ 4, "Shutter priority" },
	512	{ 5, "Creative program" },
	513	{ 6, "Action program" },
	514	{ 7, "Portrait mode" },
	515	{ 8, "Landscape mode" },
516	};
517
518	static tag_map metering_mode_values[] =
519	{
520	{ 0, "unknown" },
521	{ 1, "Average" },
522	{ 2, "CenterWeightedAverage" },
523	{ 3, "Spot" },
524	{ 4, "MultiSpot" },
525	{ 5, "Pattern" },
526	{ 6, "Partial" },
527	{ 255, "other" },
528	};
529
530	static tag_map light_source_values[] =
531	{
532	{ 0, "unknown" },
533	{ 1, "Daylight" },
534	{ 2, "Fluorescent" },
535	{ 3, "Tungsten (incandescent light)" },
536	{ 4, "Flash" },
537	{ 9, "Fine weather" },
538	{ 10, "Cloudy weather" },
539	{ 11, "Shade" },
540