/*
* Copyright (c) 2003-2005, Eric M. Johnston <emj@postal.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Eric M. Johnston.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: exifgps.c,v 1.14 2007/12/15 20:57:10 ejohnst Exp $
*/
/*
* Exif GPS information tags.
*
* Note: things aren't quite complete. Waiting on additional examples
* that include the tags marked unknown.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "exif.h"
#include "exifint.h"
#define DEGREE "°"
/* Speed. */
static struct descrip gps_speed[] = {
{ 'K', "km/h" },
{ 'M', "mph" },
{ 'N', "knots" },
{ -1, "" },
};
/* Status. */
static struct descrip gps_status[] = {
{ 'A', "Measurement In Progress" },
{ 'V', "Measurement Interoperability" },
{ -1, "Unknown" },
};
/* Distance. */
static struct descrip gps_dist[] = {
{ 'K', "km" },
{ 'M', "mi" },
{ 'N', "knots" },
{ -1, "" },
};
/* Differential correction. */
static struct descrip gps_diff[] = {
{ 0, "No Correction" },
{ 1, "Correction Applied" },
{ -1, "Unknown" },
};
/* Bearing reference. */
static struct descrip gps_bear[] = {
{ 'M', "Magnetic North" },
{ 'T', "True North" },
{ -1, "Unknown" },
};
/* GPS info version 2.2.0.0 tags. */
struct exiftag gpstags[] = {
{ 0x0000, TIFF_BYTE, 4, ED_VRB,
"GPSVersionID", "GPS Info Version", NULL },
{ 0x0001, TIFF_ASCII, 2, ED_VRB,
"GPSLatitudeRef", "Latitude Reference", NULL },
{ 0x0002, TIFF_RTNL, 3, ED_IMG,
"GPSLatitude", "Latitude", NULL },
{ 0x0003, TIFF_ASCII, 2, ED_VRB,
"GPSLongitudeRef", "Longitude Reference", NULL },
{ 0x0004, TIFF_RTNL, 3, ED_IMG,
"GPSLongitude", "Longitude", NULL },
{ 0x0005, TIFF_BYTE, 1, ED_VRB,
"GPSAltitudeRef", "Altitude Reference", NULL },
{ 0x0006, TIFF_RTNL, 1, ED_IMG, /* meters */
"GPSAltitude", "Altitude", NULL },
{ 0x0007, TIFF_RTNL, 3, ED_IMG,
"GPSTimeStamp", "Time (UTC)", NULL },
{ 0x0008, TIFF_ASCII, 0, ED_IMG,
"GPSSatellites", "GPS Satellites", NULL },
{ 0x0009, TIFF_ASCII, 2, ED_IMG,
"GPSStatus", "GPS Status", gps_status },
{ 0x000a, TIFF_ASCII, 2, ED_IMG,
"GPSMeasureMode", "GPS Measurement Mode", NULL },
{ 0x000b, TIFF_RTNL, 1, ED_UNK,
"GPSDOP", "GPS Degree of Precision", NULL },
{ 0x000c, TIFF_ASCII, 2, ED_VRB,
"GPSSpeedRef", "GPS Speed Reference", gps_speed },
{ 0x000d, TIFF_RTNL, 1, ED_UNK,
"GPSSpeed", "Movement Speed", NULL },
{ 0x000e, TIFF_ASCII, 2, ED_VRB,
"GPSTrackRef", "GPS Direction Reference", gps_bear },
{ 0x000f, TIFF_RTNL, 1, ED_UNK, /* degrees */
"GPSTrack", "Movement Direction", NULL },
{ 0x0010, TIFF_ASCII, 2, ED_VRB,
"GPSImgDirectionRef", "GPS Image Direction Ref", gps_bear },
{ 0x0011, TIFF_RTNL, 1, ED_UNK, /* degrees */
"GPSImgDirection", "Image Direction", NULL },
{ 0x0012, TIFF_ASCII, 0, ED_IMG,
"GPSMapDatum", "Geodetic Survey Data", NULL },
{ 0x0013, TIFF_ASCII, 2, ED_VRB,
"GPSDestLatitudeRef", "GPS Dest Latitude Ref", NULL },
{ 0x0014, TIFF_RTNL, 3, ED_IMG,
"GPSDestLatitude", "Destination Latitude", NULL },
{ 0x0015, TIFF_ASCII, 2, ED_VRB,
"GPSDestLongitudeRef", "GPS Dest Longitude Ref", NULL },
{ 0x0016, TIFF_RTNL, 3, ED_IMG,
"GPSDestLongitude", "Destination Longitude", NULL },
{ 0x0017, TIFF_ASCII, 2, ED_VRB,
"GPSDestBearingRef", "GPS Dest Bearing Ref", gps_bear },
{ 0x0018, TIFF_RTNL, 1, ED_UNK, /* degrees */
"GPSDestBearing", "Destination Direction", NULL },
{ 0x0019, TIFF_ASCII, 2, ED_VRB,
"GPSDestDistanceRef", "GPS Dest Distance Ref", gps_dist },
{ 0x001a, TIFF_RTNL, 1, ED_UNK,
"GPSDestDistance", "Destination Distance", NULL },
{ 0x001b, TIFF_UNDEF, 0, ED_IMG,
"GPSProcessingMethod", "GPS Processing Method", NULL },
{ 0x001c, TIFF_UNDEF, 0, ED_IMG,
"GPSAreaInformation", "GPS Area", NULL },
{ 0x001d, TIFF_ASCII, 11, ED_IMG,
"GPSDateStamp", "Date (UTC)", NULL },
{ 0x001e, TIFF_SHORT, 1, ED_IMG,
"GPSDifferental", "GPS Differential Correction", gps_diff },
{ 0xffff, TIFF_UNKN, 0, ED_UNK,
"Unknown", NULL, NULL },
};
/*
* Process GPS tags.
*/
void
gpsprop(struct exifprop *prop, struct exiftags *t)
{
u_int32_t i, n, d;
double deg, min, sec, alt;
char fmt[32], buf[16];
struct exifprop *tmpprop;
enum byteorder o = t->md.order;
switch (prop->tag) {
/* Version. */
case 0x0000:
exifstralloc(&prop->str, 8);
/* Convert the value back into a string. */
byte4exif(prop->value, (unsigned char *)buf, o);
for (i = 0; i < 4; i++) {
prop->str[i * 2] = '0' + buf[i];
prop->str[i * 2 + 1] = '.';
}
prop->str[7] = '\0';
break;
/*
* Reference values. The value is 2-count nul-terminated ASCII,
* not an offset to the ASCII string.
* XXX Shouldn't really be necessary now that short ASCII strings work.
*/
case 0x0001:
case 0x0003:
case 0x0009:
case 0x000a:
case 0x000c:
case 0x000e:
case 0x0010:
case 0x0013:
case 0x0015:
case 0x0017:
case 0x0019:
/* Clean-up from any earlier processing. */
free(prop->str);
prop->str = NULL;
byte4exif(prop->value, (unsigned char *)buf, o);
for (i = 0; gpstags[i].tag < EXIF_T_UNKNOWN &&
gpstags[i].tag != prop->tag; i++);
if (gpstags[i].table)
prop->str = finddescr(gpstags[i].table,
(unsigned char)buf[0]);
else {
exifstralloc(&prop->str, 2);
prop->str[0] = buf[0];
}
break;
/*
* Coordinate values.
*
* This is really kind of a mess. The display behavior here is
* based on image samples from a Nikon D1X and a Fuji FinePix S1 Pro.
* The specification allows for fractional minutes (and no seconds).
* Not sure if there are any other combinations...
*/
case 0x0002:
case 0x0004:
case 0x0014:
case 0x0016:
if (prop->count != 3) {
exifwarn("unexpected GPS coordinate values");
prop->lvl = ED_BAD;
break;
}
free(prop->str);
prop->str = NULL;
exifstralloc(&prop->str, 32);
/* Figure out the reference prefix. */
switch (prop->tag) {
case 0x0002:
tmpprop = findprop(t->props, gpstags, 0x0001);
break;
case 0x0004:
tmpprop = findprop(t->props, gpstags, 0x0003);
break;
case 0x0014:
tmpprop = findprop(t->props, gpstags, 0x0013);
break;
case 0x0016:
tmpprop = findprop(t->props, gpstags, 0x0015);
break;
default:
tmpprop = NULL;
}
/* Degrees. */
i = 0;
n = exif4byte(t->md.btiff + prop->value + i * 8, o);
d = exif4byte(t->md.btiff + prop->value + 4 + i * 8, o);
strcpy(fmt, "%s %.f%s ");
if (!n || !d) /* Punt. */
deg = 0.0;
else {
deg = (double)n / (double)d;
if (d != 1)
sprintf(fmt, "%%s %%.%df%%s ",
(int)log10((double)d));
}
/* Minutes. */
i++;
n = exif4byte(t->md.btiff + prop->value + i * 8, o);
d = exif4byte(t->md.btiff + prop->value + 4 + i * 8, o);
if (!n || !d) { /* Punt. */
min = 0.0;
strcat(fmt, "%.f'");
} else {
min = (double)n / (double)d;
if (d != 1) {
sprintf(buf, "%%.%df'", (int)log10((double)d));
strcat(fmt, buf);
} else
strcat(fmt, "%.f'");
}
/*
* Seconds. We'll assume if minutes are fractional, we
* should just ignore seconds.
*/
i++;
n = exif4byte(t->md.btiff + prop->value + i * 8, o);
d = exif4byte(t->md.btiff + prop->value + 4 + i * 8, o);
if (!n || !d) { /* Assume no seconds. */
snprintf(prop->str, 31, fmt, tmpprop && tmpprop->str ?
tmpprop->str : "", deg, DEGREE, min);
break;
} else {
sec = (double)n / (double)d;
if (d != 1) {
sprintf(buf, " %%.%df", (int)log10((double)d));
strcat(fmt, buf);
} else
strcat(fmt, " %.f");
}
snprintf(prop->str, 31, fmt, tmpprop && tmpprop->str ?
tmpprop->str : "", deg, DEGREE, min, sec);
break;
/* Altitude. */
case 0x0006:
n = exif4byte(t->md.btiff + prop->value, o);
d = exif4byte(t->md.btiff + prop->value + 4, o);
/* Look up reference. Non-zero means negative altitude. */
tmpprop = findprop(t->props, gpstags, 0x0005);
if (tmpprop && tmpprop->value)
n *= -1;
if (!n || !d)
alt = 0.0;
else
alt = (double)n / (double)d;
/* Should already have a 32-byte buffer from parsetag(). */
snprintf(prop->str, 31, "%.2f m", alt);
prop->str[31] = '\0';
break;
/* Time. */
case 0x0007:
/* Should already have a 32-byte buffer from parsetag(). */
prop->str[0] = '\0';
for (i = 0; i < prop->count; i++) {
n = exif4byte(t->md.btiff + prop->value + i * 8, o);
d = exif4byte(t->md.btiff + prop->value + 4 + i * 8, o);
if (!d) break;
if (!i)
sprintf(fmt, "%%02.%df", (int)log10((double)d));
else
sprintf(fmt, ":%%02.%df",
(int)log10((double)d));
snprintf(buf, 8, fmt, (double)n / (double)d);
strcat(prop->str, buf);
}
break;
}
}