src/gpx.c

   1 /*
   2  * viking -- GPS Data and Topo Analyzer, Explorer, and Manager
   3  *
   4  * Copyright (C) 2003-2005, Evan Battaglia <gtoevan@gmx.net>
   5  *
   6  * Some of the code adapted from GPSBabel 1.2.7
   7  * http://gpsbabel.sf.net/
   8  * Copyright (C) 2002, 2003, 2004, 2005 Robert Lipe, robertlipe@usa.net
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  */
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #define _XOPEN_SOURCE /* glibc2 needs this */
  30
  31 #include "gpx.h"
  32 #include "viking.h"
  33 #include <expat.h>
  34 #ifdef HAVE_STRING_H
  35 #include <string.h>
  36 #endif
  37 #include <glib.h>
  38 #ifdef HAVE_MATH_H
  39 #include <math.h>
  40 #endif
  41 #include <time.h>
  42
  43 typedef enum {
  44         tt_unknown = 0,
  45
  46         tt_gpx,
  47
  48         tt_wpt,
  49         tt_wpt_desc,
  50         tt_wpt_name,
  51         tt_wpt_ele,
  52         tt_wpt_sym,
  53         tt_wpt_link,            /* New in GPX 1.1 */
  54
  55         tt_trk,
  56         tt_trk_desc,
  57         tt_trk_name,
  58
  59         tt_trk_trkseg,
  60         tt_trk_trkseg_trkpt,
  61         tt_trk_trkseg_trkpt_ele,
  62         tt_trk_trkseg_trkpt_time,
  63         /* extended */
  64         tt_trk_trkseg_trkpt_course,
  65         tt_trk_trkseg_trkpt_speed,
  66         tt_trk_trkseg_trkpt_fix,
  67         tt_trk_trkseg_trkpt_sat,
  68
  69         tt_waypoint,
  70         tt_waypoint_coord,
  71         tt_waypoint_name,
  72 } tag_type;
  73
  74 typedef struct tag_mapping {
  75         tag_type tag_type;              /* enum from above for this tag */
  76         const char *tag_name;           /* xpath-ish tag name */
  77 } tag_mapping;
  78
  79 typedef struct {
  80         GpxWritingOptions *options;
  81         FILE *file;
  82 } GpxWritingContext;
  83
  84 /*
  85  * xpath(ish) mappings between full tag paths and internal identifers.
  86  * These appear in the order they appear in the GPX specification.
  87  * If it's not a tag we explictly handle, it doesn't go here.
  88  */
  89
  90 tag_mapping tag_path_map[] = {
  91
  92         { tt_wpt, "/gpx/wpt" },
  93
  94         { tt_waypoint, "/loc/waypoint" },
  95         { tt_waypoint_coord, "/loc/waypoint/coord" },
  96         { tt_waypoint_name, "/loc/waypoint/name" },
  97
  98         { tt_wpt_ele, "/gpx/wpt/ele" },
  99         { tt_wpt_name, "/gpx/wpt/name" },
 100         { tt_wpt_desc, "/gpx/wpt/desc" },
 101         { tt_wpt_sym, "/gpx/wpt/sym" },
 102         { tt_wpt_sym, "/loc/waypoint/type" },
 103         { tt_wpt_link, "/gpx/wpt/link" },                    /* GPX 1.1 */
 104
 105         { tt_trk, "/gpx/trk" },
 106         { tt_trk, "/gpx/rte" },
 107         { tt_trk_name, "/gpx/trk/name" },
 108         { tt_trk_desc, "/gpx/trk/desc" },
 109         { tt_trk_trkseg, "/gpx/trk/trkseg" },
 110         { tt_trk_trkseg_trkpt, "/gpx/trk/trkseg/trkpt" },
 111         { tt_trk_trkseg_trkpt, "/gpx/rte/rtept" },
 112         { tt_trk_trkseg_trkpt_ele, "/gpx/trk/trkseg/trkpt/ele" },
 113         { tt_trk_trkseg_trkpt_time, "/gpx/trk/trkseg/trkpt/time" },
 114         /* extended */
 115         { tt_trk_trkseg_trkpt_course, "/gpx/trk/trkseg/trkpt/course" },
 116         { tt_trk_trkseg_trkpt_speed, "/gpx/trk/trkseg/trkpt/speed" },
 117         { tt_trk_trkseg_trkpt_fix, "/gpx/trk/trkseg/trkpt/fix" },
 118         { tt_trk_trkseg_trkpt_sat, "/gpx/trk/trkseg/trkpt/sat" },
 119
 120         {0}
 121 };
 122
 123 static tag_type get_tag(const char *t)
 124 {
 125         tag_mapping *tm;
 126         for (tm = tag_path_map; tm->tag_type != 0; tm++)
 127                 if (0 == strcmp(tm->tag_name, t))
 128                         return tm->tag_type;
 129         return tt_unknown;
 130 }
 131
 132 /******************************************/
 133
 134 tag_type current_tag = tt_unknown;
 135 GString *xpath = NULL;
 136 GString *c_cdata = NULL;
 137
 138 /* current ("c_") objects */
 139 VikTrackpoint *c_tp = NULL;
 140 VikWaypoint *c_wp = NULL;
 141 VikTrack *c_tr = NULL;
 142
 143 gchar *c_wp_name = NULL;
 144 gchar *c_tr_name = NULL;
 145
 146 /* temporary things so we don't have to create them lots of times */
 147 const gchar *c_slat, *c_slon;
 148 struct LatLon c_ll;
 149
 150 /* specialty flags / etc */
 151 gboolean f_tr_newseg;
 152 guint unnamed_waypoints = 0;
 153 guint unnamed_tracks = 0;
 154
 155
 156 static const char *get_attr ( const char **attr, const char *key )
 157 {
 158   while ( *attr ) {
 159     if ( strcmp(*attr,key) == 0 )
 160       return *(attr + 1);
 161     attr += 2;
 162   }
 163   return NULL;
 164 }
 165
 166 static gboolean set_c_ll ( const char **attr )
 167 {
 168   if ( (c_slat = get_attr ( attr, "lat" )) && (c_slon = get_attr ( attr, "lon" )) ) {
 169     c_ll.lat = g_strtod(c_slat, NULL);
 170     c_ll.lon = g_strtod(c_slon, NULL);
 171     return TRUE;
 172   }
 173   return FALSE;
 174 }
 175
 176 static void gpx_start(VikTrwLayer *vtl, const char *el, const char **attr)
 177 {
 178   static const gchar *tmp;
 179
 180   g_string_append_c ( xpath, '/' );
 181   g_string_append ( xpath, el );
 182   current_tag = get_tag ( xpath->str );
 183
 184   switch ( current_tag ) {
 185
 186      case tt_wpt:
 187        if ( set_c_ll( attr ) ) {
 188          c_wp = vik_waypoint_new ();
 189          c_wp->altitude = VIK_DEFAULT_ALTITUDE;
 190          if ( ! get_attr ( attr, "hidden" ) )
 191            c_wp->visible = TRUE;
 192
 193          vik_coord_load_from_latlon ( &(c_wp->coord), vik_trw_layer_get_coord_mode ( vtl ), &c_ll );
 194        }
 195        break;
 196
 197      case tt_trk:
 198        c_tr = vik_track_new ();
 199        if ( ! get_attr ( attr, "hidden" ) )
 200          c_tr->visible = TRUE;
 201        break;
 202
 203      case tt_trk_trkseg:
 204        f_tr_newseg = TRUE;
 205        break;
 206
 207      case tt_trk_trkseg_trkpt:
 208        if ( set_c_ll( attr ) ) {
 209          c_tp = vik_trackpoint_new ();
 210          c_tp->altitude = VIK_DEFAULT_ALTITUDE;
 211          vik_coord_load_from_latlon ( &(c_tp->coord), vik_trw_layer_get_coord_mode ( vtl ), &c_ll );
 212          if ( f_tr_newseg ) {
 213            c_tp->newsegment = TRUE;
 214            f_tr_newseg = FALSE;
 215          }
 216          c_tr->trackpoints = g_list_append ( c_tr->trackpoints, c_tp );
 217        }
 218        break;
 219
 220      case tt_trk_trkseg_trkpt_ele:
 221      case tt_trk_trkseg_trkpt_time:
 222      case tt_wpt_desc:
 223      case tt_wpt_name:
 224      case tt_wpt_ele:
 225      case tt_wpt_link:
 226      case tt_trk_desc:
 227      case tt_trk_name:
 228        g_string_erase ( c_cdata, 0, -1 ); /* clear the cdata buffer */
 229        break;
 230
 231      case tt_waypoint:
 232        c_wp = vik_waypoint_new ();
 233        c_wp->altitude = VIK_DEFAULT_ALTITUDE;
 234        c_wp->visible = TRUE;
 235        break;
 236
 237      case tt_waypoint_coord:
 238        if ( set_c_ll( attr ) )
 239          vik_coord_load_from_latlon ( &(c_wp->coord), vik_trw_layer_get_coord_mode ( vtl ), &c_ll );
 240        break;
 241
 242      case tt_waypoint_name:
 243        if ( ( tmp = get_attr(attr, "id") ) ) {
 244          if ( c_wp_name )
 245            g_free ( c_wp_name );
 246          c_wp_name = g_strdup ( tmp );
 247        }
 248        g_string_erase ( c_cdata, 0, -1 ); /* clear the cdata buffer for description */
 249        break;
 250
 251      default: break;
 252   }
 253 }
 254
 255 static void gpx_end(VikTrwLayer *vtl, const char *el)
 256 {
 257   static GTimeVal tp_time;
 258
 259   g_string_truncate ( xpath, xpath->len - strlen(el) - 1 );
 260
 261   switch ( current_tag ) {
 262
 263      case tt_waypoint:
 264      case tt_wpt:
 265        if ( ! c_wp_name )
 266          c_wp_name = g_strdup_printf("VIKING_WP%d", unnamed_waypoints++);
 267        vik_trw_layer_filein_add_waypoint ( vtl, c_wp_name, c_wp );
 268        g_free ( c_wp_name );
 269        c_wp = NULL;
 270        c_wp_name = NULL;
 271        break;
 272
 273      case tt_trk:
 274        if ( ! c_tr_name )
 275          c_tr_name = g_strdup_printf("VIKING_TR%d", unnamed_waypoints++);
 276        vik_trw_layer_filein_add_track ( vtl, c_tr_name, c_tr );
 277        g_free ( c_tr_name );
 278        c_tr = NULL;
 279        c_tr_name = NULL;
 280        break;
 281
 282      case tt_wpt_name:
 283        if ( c_wp_name )
 284          g_free ( c_wp_name );
 285        c_wp_name = g_strdup ( c_cdata->str );
 286        g_string_erase ( c_cdata, 0, -1 );
 287        break;
 288
 289      case tt_trk_name:
 290        if ( c_tr_name )
 291          g_free ( c_tr_name );
 292        c_tr_name = g_strdup ( c_cdata->str );
 293        g_string_erase ( c_cdata, 0, -1 );
 294        break;
 295
 296      case tt_wpt_ele:
 297        c_wp->altitude = g_strtod ( c_cdata->str, NULL );
 298        g_string_erase ( c_cdata, 0, -1 );
 299        break;
 300
 301      case tt_trk_trkseg_trkpt_ele:
 302        c_tp->altitude = g_strtod ( c_cdata->str, NULL );
 303        g_string_erase ( c_cdata, 0, -1 );
 304        break;
 305
 306      case tt_waypoint_name: /* .loc name is really description. */
 307      case tt_wpt_desc:
 308        vik_waypoint_set_comment ( c_wp, c_cdata->str );
 309        g_string_erase ( c_cdata, 0, -1 );
 310        break;
 311
 312      case tt_wpt_link:
 313        vik_waypoint_set_image ( c_wp, c_cdata->str );
 314        g_string_erase ( c_cdata, 0, -1 );
 315        break;
 316
 317      case tt_wpt_sym: {
 318        gchar *tmp_lower = g_utf8_strdown(c_cdata->str, -1); /* for things like <type>Geocache</type> */
 319        vik_waypoint_set_symbol ( c_wp, tmp_lower );
 320        g_free ( tmp_lower );
 321        g_string_erase ( c_cdata, 0, -1 );
 322        break;
 323        }
 324
 325      case tt_trk_desc:
 326        vik_track_set_comment ( c_tr, c_cdata->str );
 327        g_string_erase ( c_cdata, 0, -1 );
 328        break;
 329
 330      case tt_trk_trkseg_trkpt_time:
 331        if ( g_time_val_from_iso8601(c_cdata->str, &tp_time) ) {
 332          c_tp->timestamp = tp_time.tv_sec;
 333          c_tp->has_timestamp = TRUE;
 334        }
 335        g_string_erase ( c_cdata, 0, -1 );
 336        break;
 337
 338      case tt_trk_trkseg_trkpt_course:
 339        c_tp->extended = TRUE;
 340        c_tp->course = g_strtod ( c_cdata->str, NULL );
 341        g_string_erase ( c_cdata, 0, -1 );
 342        break;
 343
 344      case tt_trk_trkseg_trkpt_speed:
 345        c_tp->extended = TRUE;
 346        c_tp->speed = g_strtod ( c_cdata->str, NULL );
 347        g_string_erase ( c_cdata, 0, -1 );
 348        break;
 349
 350      case tt_trk_trkseg_trkpt_fix:
 351        c_tp->extended = TRUE;
 352        if (!strcmp("2d", c_cdata->str))
 353          c_tp->fix_mode = VIK_GPS_MODE_2D;
 354        else if (!strcmp("3d", c_cdata->str))
 355          c_tp->fix_mode = VIK_GPS_MODE_3D;
 356        else  /* TODO: more fix modes here */
 357          c_tp->fix_mode = VIK_GPS_MODE_NOT_SEEN;
 358        g_string_erase ( c_cdata, 0, -1 );
 359        break;
 360
 361      case tt_trk_trkseg_trkpt_sat:
 362        c_tp->extended = TRUE;
 363        c_tp->nsats = atoi ( c_cdata->str );
 364        g_string_erase ( c_cdata, 0, -1 );
 365        break;
 366
 367      default: break;
 368   }
 369
 370   current_tag = get_tag ( xpath->str );
 371 }
 372
 373 static void gpx_cdata(void *dta, const XML_Char *s, int len)
 374 {
 375   switch ( current_tag ) {
 376     case tt_wpt_name:
 377     case tt_trk_name:
 378     case tt_wpt_ele:
 379     case tt_trk_trkseg_trkpt_ele:
 380     case tt_wpt_desc:
 381     case tt_wpt_sym:
 382     case tt_wpt_link:
 383     case tt_trk_desc:
 384     case tt_trk_trkseg_trkpt_time:
 385     case tt_trk_trkseg_trkpt_course:
 386     case tt_trk_trkseg_trkpt_speed:
 387     case tt_trk_trkseg_trkpt_fix:
 388     case tt_trk_trkseg_trkpt_sat:
 389     case tt_waypoint_name: /* .loc name is really description. */
 390       g_string_append_len ( c_cdata, s, len );
 391       break;
 392
 393     default: break;  /* ignore cdata from other things */
 394   }
 395 }
 396
 397 // make like a "stack" of tag names
 398 // like gpspoint's separated like /gpx/wpt/whatever
 399
 400 void a_gpx_read_file( VikTrwLayer *vtl, FILE *f ) {
 401   XML_Parser parser = XML_ParserCreate(NULL);
 402   int done=0, len;
 403
 404   XML_SetElementHandler(parser, (XML_StartElementHandler) gpx_start, (XML_EndElementHandler) gpx_end);
 405   XML_SetUserData(parser, vtl); /* in the future we could remove all global variables */
 406   XML_SetCharacterDataHandler(parser, (XML_CharacterDataHandler) gpx_cdata);
 407
 408   gchar buf[4096];
 409
 410   g_assert ( f != NULL && vtl != NULL );
 411
 412   xpath = g_string_new ( "" );
 413   c_cdata = g_string_new ( "" );
 414
 415   unnamed_waypoints = 0;
 416   unnamed_tracks = 0;
 417
 418   while (!done) {
 419     len = fread(buf, 1, sizeof(buf)-7, f);
 420     done = feof(f) || !len;
 421     XML_Parse(parser, buf, len, done);
 422   }
 423
 424   XML_ParserFree (parser);
 425   g_string_free ( xpath, TRUE );
 426   g_string_free ( c_cdata, TRUE );
 427 }
 428
 429 /**** entitize from GPSBabel ****/
 430 typedef struct {
 431         const char * text;
 432         const char * entity;
 433         int  not_html;
 434 } entity_types;
 435
 436 static
 437 entity_types stdentities[] =  {
 438         { "&",  "&amp;", 0 },
 439         { "'",  "&apos;", 1 },
 440         { "<",  "&lt;", 0 },
 441         { ">",  "&gt;", 0 },
 442         { "\"", "&quot;", 0 },
 443         { NULL, NULL, 0 }
 444 };
 445
 446 void utf8_to_int( const char *cp, int *bytes, int *value )
 447 {
 448         if ( (*cp & 0xe0) == 0xc0 ) {
 449                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 450                 *bytes = 2;
 451                 *value = ((*cp & 0x1f) << 6) |
 452                         (*(cp+1) & 0x3f);
 453         }
 454         else if ( (*cp & 0xf0) == 0xe0 ) {
 455                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 456                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 457                 *bytes = 3;
 458                 *value = ((*cp & 0x0f) << 12) |
 459                         ((*(cp+1) & 0x3f) << 6) |
 460                         (*(cp+2) & 0x3f);
 461         }
 462         else if ( (*cp & 0xf8) == 0xf0 ) {
 463                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 464                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 465                 if ( (*(cp+3) & 0xc0) != 0x80 ) goto dodefault;
 466                 *bytes = 4;
 467                 *value = ((*cp & 0x07) << 18) |
 468                         ((*(cp+1) & 0x3f) << 12) |
 469                         ((*(cp+2) & 0x3f) << 6) |
 470                         (*(cp+3) & 0x3f);
 471         }
 472         else if ( (*cp & 0xfc) == 0xf8 ) {
 473                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 474                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 475                 if ( (*(cp+3) & 0xc0) != 0x80 ) goto dodefault;
 476                 if ( (*(cp+4) & 0xc0) != 0x80 ) goto dodefault;
 477                 *bytes = 5;
 478                 *value = ((*cp & 0x03) << 24) |
 479                         ((*(cp+1) & 0x3f) << 18) |
 480                         ((*(cp+2) & 0x3f) << 12) |
 481                         ((*(cp+3) & 0x3f) << 6) |
 482                         (*(cp+4) & 0x3f);
 483         }
 484         else if ( (*cp & 0xfe) == 0xfc ) {
 485                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 486                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 487                 if ( (*(cp+3) & 0xc0) != 0x80 ) goto dodefault;
 488                 if ( (*(cp+4) & 0xc0) != 0x80 ) goto dodefault;
 489                 if ( (*(cp+5) & 0xc0) != 0x80 ) goto dodefault;
 490                 *bytes = 6;
 491                 *value = ((*cp & 0x01) << 30) |
 492                         ((*(cp+1) & 0x3f) << 24) |
 493                         ((*(cp+2) & 0x3f) << 18) |
 494                         ((*(cp+3) & 0x3f) << 12) |
 495                         ((*(cp+4) & 0x3f) << 6) |
 496                         (*(cp+5) & 0x3f);
 497         }
 498         else {
 499 dodefault:
 500                 *bytes = 1;
 501                 *value = (unsigned char)*cp;
 502         }
 503 }
 504
 505 static
 506 char *
 507 entitize(const char * str)
 508 {
 509         int elen, ecount, nsecount;
 510         entity_types *ep;
 511         const char * cp;
 512         char * p, * tmp, * xstr;
 513
 514         char tmpsub[20];
 515         int bytes = 0;
 516         int value = 0;
 517         ep = stdentities;
 518         elen = ecount = nsecount = 0;
 519
 520         /* figure # of entity replacements and additional size. */
 521         while (ep->text) {
 522                 cp = str;
 523                 while ((cp = strstr(cp, ep->text)) != NULL) {
 524                         elen += strlen(ep->entity) - strlen(ep->text);
 525                         ecount++;
 526                         cp += strlen(ep->text);
 527                 }
 528                 ep++;
 529         }
 530
 531         /* figure the same for other than standard entities (i.e. anything
 532          * that isn't in the range U+0000 to U+007F */
 533         for ( cp = str; *cp; cp++ ) {
 534                 if ( *cp & 0x80 ) {
 535
 536                         utf8_to_int( cp, &bytes, &value );
 537                         cp += bytes-1;
 538                         elen += sprintf( tmpsub, "&#x%x;", value ) - bytes;
 539                         nsecount++;
 540                 }
 541         }
 542
 543         /* enough space for the whole string plus entity replacements, if any */
 544         tmp = g_malloc((strlen(str) + elen + 1));
 545         strcpy(tmp, str);
 546
 547         /* no entity replacements */
 548         if (ecount == 0 && nsecount == 0)
 549                 return (tmp);
 550
 551         if ( ecount != 0 ) {
 552                 for (ep = stdentities; ep->text; ep++) {
 553                         p = tmp;
 554                         while ((p = strstr(p, ep->text)) != NULL) {
 555                                 elen = strlen(ep->entity);
 556
 557                                 xstr = g_strdup(p + strlen(ep->text));
 558
 559                                 strcpy(p, ep->entity);
 560                                 strcpy(p + elen, xstr);
 561
 562                                 g_free(xstr);
 563
 564                                 p += elen;
 565                         }
 566                 }
 567         }
 568
 569         if ( nsecount != 0 ) {
 570                 p = tmp;
 571                 while (*p) {
 572                         if ( *p & 0x80 ) {
 573                                 utf8_to_int( p, &bytes, &value );
 574                                 if ( p[bytes] ) {
 575                                         xstr = g_strdup( p + bytes );
 576                                 }
 577                                 else {
 578                                         xstr = NULL;
 579                                 }
 580                                 sprintf( p, "&#x%x;", value );
 581                                 p = p+strlen(p);
 582                                 if ( xstr ) {
 583                                         strcpy( p, xstr );
 584                                         g_free(xstr);
 585                                 }
 586                         }
 587                         else {
 588                                 p++;
 589                         }
 590                 }
 591         }
 592         return (tmp);
 593 }
 594 /**** end GPSBabel code ****/
 595
 596 /* export GPX */
 597
 598 static void gpx_write_waypoint ( const gchar *name, VikWaypoint *wp, GpxWritingContext *context )
 599 {
 600   FILE *f = context->file;
 601   static struct LatLon ll;
 602   gchar *s_lat,*s_lon;
 603   gchar *tmp;
 604   vik_coord_to_latlon ( &(wp->coord), &ll );
 605   s_lat = a_coords_dtostr( ll.lat );
 606   s_lon = a_coords_dtostr( ll.lon );
 607   fprintf ( f, "<wpt lat=\"%s\" lon=\"%s\"%s>\n",
 608                s_lat, s_lon, wp->visible ? "" : " hidden=\"hidden\"" );
 609   g_free ( s_lat );
 610   g_free ( s_lon );
 611
 612   tmp = entitize ( name );
 613   fprintf ( f, "  <name>%s</name>\n", tmp );
 614   g_free ( tmp);
 615
 616   if ( wp->altitude != VIK_DEFAULT_ALTITUDE )
 617   {
 618     tmp = a_coords_dtostr ( wp->altitude );
 619     fprintf ( f, "  <ele>%s</ele>\n", tmp );
 620     g_free ( tmp );
 621   }
 622   if ( wp->comment )
 623   {
 624     tmp = entitize(wp->comment);
 625     fprintf ( f, "  <desc>%s</desc>\n", tmp );
 626     g_free ( tmp );
 627   }
 628   if ( wp->image )
 629   {
 630     tmp = entitize(wp->image);
 631     fprintf ( f, "  <link>%s</link>\n", tmp );
 632     g_free ( tmp );
 633   }
 634   if ( wp->symbol )
 635   {
 636     tmp = entitize(wp->symbol);
 637     fprintf ( f, "  <sym>%s</sym>\n", tmp);
 638     g_free ( tmp );
 639   }
 640
 641   fprintf ( f, "</wpt>\n" );
 642 }
 643
 644 static void gpx_write_trackpoint ( VikTrackpoint *tp, GpxWritingContext *context )
 645 {
 646   FILE *f = context->file;
 647   static struct LatLon ll;
 648   gchar *s_lat,*s_lon, *s_alt;
 649   gchar *time_iso8601;
 650   vik_coord_to_latlon ( &(tp->coord), &ll );
 651
 652   if ( tp->newsegment )
 653     fprintf ( f, "  </trkseg>\n  <trkseg>\n" );
 654
 655   s_lat = a_coords_dtostr( ll.lat );
 656   s_lon = a_coords_dtostr( ll.lon );
 657   fprintf ( f, "  <trkpt lat=\"%s\" lon=\"%s\">\n", s_lat, s_lon );
 658   g_free ( s_lat ); s_lat = NULL;
 659   g_free ( s_lon ); s_lon = NULL;
 660
 661   s_alt = NULL;
 662   if ( tp->altitude != VIK_DEFAULT_ALTITUDE )
 663   {
 664     s_alt = a_coords_dtostr ( tp->altitude );
 665   }
 666   else if ( context->options != NULL && context->options->force_ele )
 667   {
 668     s_alt = a_coords_dtostr ( 0 );
 669   }
 670   if (s_alt != NULL)
 671     fprintf ( f, "    <ele>%s</ele>\n", s_alt );
 672   g_free ( s_alt ); s_alt = NULL;
 673
 674   time_iso8601 = NULL;
 675   if ( tp->has_timestamp ) {
 676     GTimeVal timestamp;
 677     timestamp.tv_sec = tp->timestamp;
 678     timestamp.tv_usec = 0;
 679
 680     time_iso8601 = g_time_val_to_iso8601 ( &timestamp );
 681   }
 682   else if ( context->options != NULL && context->options->force_time )
 683   {
 684     GTimeVal current;
 685     g_get_current_time ( &current );
 686
 687     time_iso8601 = g_time_val_to_iso8601 ( &current );
 688   }
 689   if ( time_iso8601 != NULL )
 690     fprintf ( f, "    <time>%s</time>\n", time_iso8601 );
 691   g_free(time_iso8601);
 692   time_iso8601 = NULL;
 693
 694   if (tp->extended && (tp->fix_mode >= VIK_GPS_MODE_2D)) {
 695     if (!isnan(tp->course)) {
 696       gchar *s_course = a_coords_dtostr(tp->course);
 697       fprintf ( f, "    <course>%s</course>\n", s_course );
 698       g_free(s_course);
 699     }
 700     if (!isnan(tp->speed)) {
 701       gchar *s_speed = a_coords_dtostr(tp->speed);
 702       fprintf ( f, "    <speed>%s</speed>\n", s_speed );
 703       g_free(s_speed);
 704     }
 705     if (tp->fix_mode == VIK_GPS_MODE_2D)
 706       fprintf ( f, "    <fix>2d</fix>\n");
 707     if (tp->fix_mode == VIK_GPS_MODE_3D)
 708       fprintf ( f, "    <fix>3d</fix>\n");
 709     if (tp->nsats > 0)
 710       fprintf ( f, "    <sat>%d</sat>\n", tp->nsats );
 711   }
 712
 713   fprintf ( f, "  </trkpt>\n" );
 714 }
 715
 716
 717 static void gpx_write_track ( const gchar *name, VikTrack *t, GpxWritingContext *context )
 718 {
 719   FILE *f = context->file;
 720   gchar *tmp;
 721   gboolean first_tp_is_newsegment = FALSE; /* must temporarily make it not so, but we want to restore state. not that it matters. */
 722
 723   tmp = entitize ( name );
 724   fprintf ( f, "<trk%s>\n  <name>%s</name>\n", t->visible ? "" : " hidden=\"hidden\"", tmp );
 725   g_free ( tmp );
 726
 727   if ( t->comment )
 728   {
 729     tmp = entitize ( t->comment );
 730     fprintf ( f, "  <desc>%s</desc>\n", tmp );
 731     g_free ( tmp );
 732   }
 733
 734   fprintf ( f, "  <trkseg>\n" );
 735
 736   if ( t->trackpoints && t->trackpoints->data ) {
 737     first_tp_is_newsegment = VIK_TRACKPOINT(t->trackpoints->data)->newsegment;
 738     VIK_TRACKPOINT(t->trackpoints->data)->newsegment = FALSE; /* so we won't write </trkseg><trkseg> already */
 739     g_list_foreach ( t->trackpoints, (GFunc) gpx_write_trackpoint, context );
 740     VIK_TRACKPOINT(t->trackpoints->data)->newsegment = first_tp_is_newsegment; /* restore state */
 741   }
 742
 743   fprintf ( f, "</trkseg>\n</trk>\n" );
 744 }
 745
 746 static void gpx_write_header( FILE *f )
 747 {
 748   fprintf(f, "<?xml version=\"1.0\"?>\n"
 749           "<gpx version=\"1.0\" creator=\"Viking -- http://viking.sf.net/\"\n"
 750           "xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
 751           "xmlns=\"http://www.topografix.com/GPX/1/0\"\n"
 752           "xsi:schemaLocation=\"http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd\">\n");
 753 }
 754
 755 static void gpx_write_footer( FILE *f )
 756 {
 757   fprintf(f, "</gpx>\n");
 758 }
 759
 760
 761
 762 typedef struct {
 763   VikWaypoint *wp;
 764   const gchar *name;
 765 } gpx_waypoint_and_name;
 766
 767 typedef struct {
 768   gpx_waypoint_and_name *wps;
 769   guint i;
 770   guint n_wps;
 771 } gpx_gather_waypoints_passalong_t;
 772
 773 /* Type to hold name of track and timestamp of first trackpoint */
 774 typedef struct {
 775   time_t first_timestamp;
 776   const gchar *name;
 777 } gpx_track_and_timestamp;
 778
 779 typedef struct {
 780   gpx_track_and_timestamp *trks;
 781   guint i;
 782   guint n_trks;
 783 } gpx_gather_tracks_passalong_t;
 784
 785 static void gpx_collect_waypoint ( const gchar *name, VikWaypoint *wp, gpx_gather_waypoints_passalong_t *passalong )
 786 {
 787   if ( passalong->i < passalong->n_wps ) {
 788     passalong->wps[passalong->i].name = name;
 789     passalong->wps[passalong->i].wp = wp;
 790     passalong->i++;
 791   }
 792 }
 793
 794 /* Function to collect a track and the first timestamp in the list */
 795 static void gpx_collect_track (const gchar *name, VikTrack *track, gpx_gather_tracks_passalong_t *passalong)
 796 {
 797   if (passalong->i < passalong->n_trks)
 798   {
 799     VikTrackpoint *first_point = (VikTrackpoint *)track->trackpoints->data;
 800     passalong->trks[passalong->i].name = name;
 801     passalong->trks[passalong->i].first_timestamp = first_point->timestamp;
 802     passalong->i++;
 803   }
 804 }
 805
 806 static int gpx_waypoint_and_name_compar(const void *x, const void *y)
 807 {
 808   gpx_waypoint_and_name *a = (gpx_waypoint_and_name *)x;
 809   gpx_waypoint_and_name *b = (gpx_waypoint_and_name *)y;
 810   return strcmp(a->name,b->name);
 811 }
 812
 813 /* Function to compare two tracks by their first timestamp */
 814 static int gpx_track_and_timestamp_compar(const void *x, const void *y)
 815 {
 816   gpx_track_and_timestamp *a = (gpx_track_and_timestamp *)x;
 817   gpx_track_and_timestamp *b = (gpx_track_and_timestamp *)y;
 818   if (a->first_timestamp < b->first_timestamp)
 819   {
 820     return -1;
 821   }
 822   if (a->first_timestamp > b->first_timestamp)
 823   {
 824     return 1;
 825   }
 826   return 0;
 827 }
 828
 829 void a_gpx_write_file( VikTrwLayer *vtl, FILE *f )
 830 {
 831         a_gpx_write_file_options(NULL, vtl, f);
 832 }
 833
 834 void a_gpx_write_file_options ( GpxWritingOptions *options, VikTrwLayer *vtl, FILE *f )
 835 {
 836   GpxWritingContext context = { options, f };
 837   int i;
 838
 839   gpx_write_header ( f );
 840
 841
 842   gpx_gather_waypoints_passalong_t passalong;
 843   passalong.n_wps = g_hash_table_size ( vik_trw_layer_get_waypoints ( vtl ) );
 844   passalong.i = 0;
 845   passalong.wps = g_new(gpx_waypoint_and_name,passalong.n_wps);
 846   g_hash_table_foreach ( vik_trw_layer_get_waypoints ( vtl ), (GHFunc) gpx_collect_waypoint, &passalong );
 847   /* gather waypoints in a list, then sort */
 848   qsort(passalong.wps, passalong.n_wps, sizeof(gpx_waypoint_and_name), gpx_waypoint_and_name_compar);
 849   for ( i = 0; i < passalong.n_wps; i++ )
 850     gpx_write_waypoint ( passalong.wps[i].name, passalong.wps[i].wp, &context);
 851   g_free ( passalong.wps );
 852
 853   gpx_gather_tracks_passalong_t passalong_tracks;
 854   passalong_tracks.n_trks = g_hash_table_size ( vik_trw_layer_get_tracks (vtl) );
 855   passalong_tracks.i = 0;
 856   passalong_tracks.trks = g_new(gpx_track_and_timestamp,passalong_tracks.n_trks);
 857   g_hash_table_foreach (vik_trw_layer_get_tracks(vtl), (GHFunc) gpx_collect_track, &passalong_tracks);
 858   /* Sort by timestamp */
 859   qsort(passalong_tracks.trks, passalong_tracks.n_trks, sizeof(gpx_track_and_timestamp), gpx_track_and_timestamp_compar);
 860   for (i=0;i<passalong_tracks.n_trks; i++)
 861   {
 862     gpx_write_track(passalong_tracks.trks[i].name, (VikTrack *)g_hash_table_lookup(vik_trw_layer_get_tracks(vtl), passalong_tracks.trks[i].name), &context);
 863   }
 864   g_free ( passalong_tracks.trks );
 865   gpx_write_footer ( f );
 866 }
 867
 868 void a_gpx_write_track_file ( const gchar *name, VikTrack *t, FILE *f )
 869 {
 870   a_gpx_write_track_file_options ( NULL, name, t, f );
 871 }
 872
 873 void a_gpx_write_track_file_options ( GpxWritingOptions *options, const gchar *name, VikTrack *t, FILE *f )
 874 {
 875   GpxWritingContext context = {options, f};
 876   gpx_write_header ( f );
 877   gpx_write_track ( name, t, &context );
 878   gpx_write_footer ( f );
 879 }