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
  26
  27 #define _XOPEN_SOURCE /* glibc2 needs this */
  28
  29 #include "viking.h"
  30 #include <expat.h>
  31 #include <string.h>
  32
  33 #define GPX_TIME_FORMAT "%Y-%m-%dT%H:%M:%SZ"
  34
  35 typedef enum {
  36         tt_unknown = 0,
  37
  38         tt_gpx,
  39
  40         tt_wpt,
  41         tt_wpt_desc,
  42         tt_wpt_name,
  43         tt_wpt_ele,
  44         tt_wpt_sym,
  45         tt_wpt_link,            /* New in GPX 1.1 */
  46
  47         tt_trk,
  48         tt_trk_desc,
  49         tt_trk_name,
  50
  51         tt_trk_trkseg,
  52         tt_trk_trkseg_trkpt,
  53         tt_trk_trkseg_trkpt_ele,
  54         tt_trk_trkseg_trkpt_time,
  55
  56         tt_waypoint,
  57         tt_waypoint_coord,
  58         tt_waypoint_name,
  59 } tag_type;
  60
  61 typedef struct tag_mapping {
  62         tag_type tag_type;              /* enum from above for this tag */
  63         const char *tag_name;           /* xpath-ish tag name */
  64 } tag_mapping;
  65
  66 /*
  67  * xpath(ish) mappings between full tag paths and internal identifers.
  68  * These appear in the order they appear in the GPX specification.
  69  * If it's not a tag we explictly handle, it doesn't go here.
  70  */
  71
  72 tag_mapping tag_path_map[] = {
  73
  74         { tt_wpt, "/gpx/wpt" },
  75
  76         { tt_waypoint, "/loc/waypoint" },
  77         { tt_waypoint_coord, "/loc/waypoint/coord" },
  78         { tt_waypoint_name, "/loc/waypoint/name" },
  79
  80         { tt_wpt_ele, "/gpx/wpt/ele" },
  81         { tt_wpt_name, "/gpx/wpt/name" },
  82         { tt_wpt_desc, "/gpx/wpt/desc" },
  83         { tt_wpt_sym, "/gpx/wpt/sym" },
  84         { tt_wpt_sym, "/loc/waypoint/type" },
  85         { tt_wpt_link, "/gpx/wpt/link" },                    /* GPX 1.1 */
  86
  87         { tt_trk, "/gpx/trk" },
  88         { tt_trk, "/gpx/rte" },
  89         { tt_trk_name, "/gpx/trk/name" },
  90         { tt_trk_desc, "/gpx/trk/desc" },
  91         { tt_trk_trkseg, "/gpx/trk/trkseg" },
  92         { tt_trk_trkseg_trkpt, "/gpx/trk/trkseg/trkpt" },
  93         { tt_trk_trkseg_trkpt, "/gpx/rte/rtept" },
  94         { tt_trk_trkseg_trkpt_ele, "/gpx/trk/trkseg/trkpt/ele" },
  95         { tt_trk_trkseg_trkpt_time, "/gpx/trk/trkseg/trkpt/time" },
  96
  97         {0}
  98 };
  99
 100 static tag_type get_tag(const char *t)
 101 {
 102         tag_mapping *tm;
 103         for (tm = tag_path_map; tm->tag_type != 0; tm++)
 104                 if (0 == strcmp(tm->tag_name, t))
 105                         return tm->tag_type;
 106         return tt_unknown;
 107 }
 108
 109 /******************************************/
 110
 111 tag_type current_tag = tt_unknown;
 112 GString *xpath = NULL;
 113 GString *c_cdata = NULL;
 114
 115 /* current ("c_") objects */
 116 VikTrackpoint *c_tp = NULL;
 117 VikWaypoint *c_wp = NULL;
 118 VikTrack *c_tr = NULL;
 119
 120 gchar *c_wp_name = NULL;
 121 gchar *c_tr_name = NULL;
 122
 123 /* temporary things so we don't have to create them lots of times */
 124 const gchar *c_slat, *c_slon;
 125 struct LatLon c_ll;
 126
 127 /* specialty flags / etc */
 128 gboolean f_tr_newseg;
 129 guint unnamed_waypoints = 0;
 130 guint unnamed_tracks = 0;
 131
 132
 133 static const char *get_attr ( const char **attr, const char *key )
 134 {
 135   while ( *attr ) {
 136     if ( strcmp(*attr,key) == 0 )
 137       return *(attr + 1);
 138     attr += 2;
 139   }
 140   return NULL;
 141 }
 142
 143 static gboolean set_c_ll ( const char **attr )
 144 {
 145   if ( (c_slat = get_attr ( attr, "lat" )) && (c_slon = get_attr ( attr, "lon" )) ) {
 146     c_ll.lat = g_strtod(c_slat, NULL);
 147     c_ll.lon = g_strtod(c_slon, NULL);
 148     return TRUE;
 149   }
 150   return FALSE;
 151 }
 152
 153 static void gpx_start(VikTrwLayer *vtl, const char *el, const char **attr)
 154 {
 155   static const gchar *tmp;
 156
 157   g_string_append_c ( xpath, '/' );
 158   g_string_append ( xpath, el );
 159   current_tag = get_tag ( xpath->str );
 160
 161   switch ( current_tag ) {
 162
 163      case tt_wpt:
 164        if ( set_c_ll( attr ) ) {
 165          c_wp = vik_waypoint_new ();
 166          c_wp->altitude = VIK_DEFAULT_ALTITUDE;
 167          if ( ! get_attr ( attr, "hidden" ) )
 168            c_wp->visible = TRUE;
 169
 170          vik_coord_load_from_latlon ( &(c_wp->coord), vik_trw_layer_get_coord_mode ( vtl ), &c_ll );
 171        }
 172        break;
 173
 174      case tt_trk:
 175        c_tr = vik_track_new ();
 176        if ( ! get_attr ( attr, "hidden" ) )
 177          c_tr->visible = TRUE;
 178        break;
 179
 180      case tt_trk_trkseg:
 181        f_tr_newseg = TRUE;
 182        break;
 183
 184      case tt_trk_trkseg_trkpt:
 185        if ( set_c_ll( attr ) ) {
 186          c_tp = vik_trackpoint_new ();
 187          c_tp->altitude = VIK_DEFAULT_ALTITUDE;
 188          vik_coord_load_from_latlon ( &(c_tp->coord), vik_trw_layer_get_coord_mode ( vtl ), &c_ll );
 189          if ( f_tr_newseg ) {
 190            c_tp->newsegment = TRUE;
 191            f_tr_newseg = FALSE;
 192          }
 193          c_tr->trackpoints = g_list_append ( c_tr->trackpoints, c_tp );
 194        }
 195        break;
 196
 197      case tt_trk_trkseg_trkpt_ele:
 198      case tt_trk_trkseg_trkpt_time:
 199      case tt_wpt_desc:
 200      case tt_wpt_name:
 201      case tt_wpt_ele:
 202      case tt_wpt_link:
 203      case tt_trk_desc:
 204      case tt_trk_name:
 205        g_string_erase ( c_cdata, 0, -1 ); /* clear the cdata buffer */
 206        break;
 207
 208      case tt_waypoint:
 209        c_wp = vik_waypoint_new ();
 210        c_wp->altitude = VIK_DEFAULT_ALTITUDE;
 211        c_wp->visible = TRUE;
 212        break;
 213
 214      case tt_waypoint_coord:
 215        if ( set_c_ll( attr ) )
 216          vik_coord_load_from_latlon ( &(c_wp->coord), vik_trw_layer_get_coord_mode ( vtl ), &c_ll );
 217        break;
 218
 219      case tt_waypoint_name:
 220        if ( ( tmp = get_attr(attr, "id") ) ) {
 221          if ( c_wp_name )
 222            g_free ( c_wp_name );
 223          c_wp_name = g_strdup ( tmp );
 224        }
 225        g_string_erase ( c_cdata, 0, -1 ); /* clear the cdata buffer for description */
 226        break;
 227
 228      default: break;
 229   }
 230 }
 231
 232 static void gpx_end(VikTrwLayer *vtl, const char *el)
 233 {
 234   static struct tm tm;
 235   g_string_truncate ( xpath, xpath->len - strlen(el) - 1 );
 236
 237   switch ( current_tag ) {
 238
 239      case tt_waypoint:
 240      case tt_wpt:
 241        if ( ! c_wp_name )
 242          c_wp_name = g_strdup_printf("VIKING_WP%d", unnamed_waypoints++);
 243        g_hash_table_insert ( vik_trw_layer_get_waypoints ( vtl ), c_wp_name, c_wp );
 244        c_wp = NULL;
 245        c_wp_name = NULL;
 246        break;
 247
 248      case tt_trk:
 249        if ( ! c_tr_name )
 250          c_tr_name = g_strdup_printf("VIKING_TR%d", unnamed_waypoints++);
 251        g_hash_table_insert ( vik_trw_layer_get_tracks ( vtl ), c_tr_name, c_tr );
 252        c_tr = NULL;
 253        c_tr_name = NULL;
 254        break;
 255
 256      case tt_wpt_name:
 257        if ( c_wp_name )
 258          g_free ( c_wp_name );
 259        c_wp_name = g_strdup ( c_cdata->str );
 260        g_string_erase ( c_cdata, 0, -1 );
 261        break;
 262
 263      case tt_trk_name:
 264        if ( c_tr_name )
 265          g_free ( c_tr_name );
 266        c_tr_name = g_strdup ( c_cdata->str );
 267        g_string_erase ( c_cdata, 0, -1 );
 268        break;
 269
 270      case tt_wpt_ele:
 271        c_wp->altitude = g_strtod ( c_cdata->str, NULL );
 272        g_string_erase ( c_cdata, 0, -1 );
 273        break;
 274
 275      case tt_trk_trkseg_trkpt_ele:
 276        c_tp->altitude = g_strtod ( c_cdata->str, NULL );
 277        g_string_erase ( c_cdata, 0, -1 );
 278        break;
 279
 280      case tt_waypoint_name: /* .loc name is really description. */
 281      case tt_wpt_desc:
 282        vik_waypoint_set_comment ( c_wp, c_cdata->str );
 283        g_string_erase ( c_cdata, 0, -1 );
 284        break;
 285
 286      case tt_wpt_link:
 287        vik_waypoint_set_image ( c_wp, c_cdata->str );
 288        g_string_erase ( c_cdata, 0, -1 );
 289        break;
 290
 291      case tt_wpt_sym: {
 292        gchar *tmp_lower = g_utf8_strdown(c_cdata->str, -1); /* for things like <type>Geocache</type> */
 293        vik_waypoint_set_symbol ( c_wp, tmp_lower );
 294        g_free ( tmp_lower );
 295        g_string_erase ( c_cdata, 0, -1 );
 296        break;
 297        }
 298
 299      case tt_trk_desc:
 300        vik_track_set_comment ( c_tr, c_cdata->str );
 301        g_string_erase ( c_cdata, 0, -1 );
 302        break;
 303
 304      case tt_trk_trkseg_trkpt_time:
 305        if ( strptime(c_cdata->str, GPX_TIME_FORMAT, &tm) != c_cdata->str ) { /* it read at least one char */
 306          c_tp->timestamp = mktime(&tm);
 307          c_tp->has_timestamp = TRUE;
 308        }
 309        g_string_erase ( c_cdata, 0, -1 );
 310        break;
 311
 312      default: break;
 313   }
 314
 315   current_tag = get_tag ( xpath->str );
 316 }
 317
 318 static void gpx_cdata(void *dta, const XML_Char *s, int len)
 319 {
 320   switch ( current_tag ) {
 321     case tt_wpt_name:
 322     case tt_trk_name:
 323     case tt_wpt_ele:
 324     case tt_trk_trkseg_trkpt_ele:
 325     case tt_wpt_desc:
 326     case tt_wpt_sym:
 327     case tt_wpt_link:
 328     case tt_trk_desc:
 329     case tt_trk_trkseg_trkpt_time:
 330     case tt_waypoint_name: /* .loc name is really description. */
 331       g_string_append_len ( c_cdata, s, len );
 332       break;
 333
 334     default: break;  /* ignore cdata from other things */
 335   }
 336 }
 337
 338 // make like a "stack" of tag names
 339 // like gpspoint's separated like /gpx/wpt/whatever
 340
 341 void a_gpx_read_file( VikTrwLayer *vtl, FILE *f ) {
 342   XML_Parser parser = XML_ParserCreate(NULL);
 343   int done=0, len;
 344
 345   XML_SetElementHandler(parser, (XML_StartElementHandler) gpx_start, (XML_EndElementHandler) gpx_end);
 346   XML_SetUserData(parser, vtl); /* in the future we could remove all global variables */
 347   XML_SetCharacterDataHandler(parser, (XML_CharacterDataHandler) gpx_cdata);
 348
 349   gchar buf[4096];
 350
 351   g_assert ( f != NULL && vtl != NULL );
 352
 353   xpath = g_string_new ( "" );
 354   c_cdata = g_string_new ( "" );
 355
 356   unnamed_waypoints = 0;
 357   unnamed_tracks = 0;
 358
 359   while (!done) {
 360     len = fread(buf, 1, sizeof(buf)-7, f);
 361     done = feof(f) || !len;
 362     XML_Parse(parser, buf, len, done);
 363   }
 364
 365   g_string_free ( xpath, TRUE );
 366   g_string_free ( c_cdata, TRUE );
 367 }
 368
 369 /**** entitize from GPSBabel ****/
 370 typedef struct {
 371         const char * text;
 372         const char * entity;
 373         int  not_html;
 374 } entity_types;
 375
 376 static
 377 entity_types stdentities[] =  {
 378         { "&",  "&amp;", 0 },
 379         { "'",  "&apos;", 1 },
 380         { "<",  "&lt;", 0 },
 381         { ">",  "&gt;", 0 },
 382         { "\"", "&quot;", 0 },
 383         { NULL, NULL, 0 }
 384 };
 385
 386 void utf8_to_int( const char *cp, int *bytes, int *value )
 387 {
 388         if ( (*cp & 0xe0) == 0xc0 ) {
 389                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 390                 *bytes = 2;
 391                 *value = ((*cp & 0x1f) << 6) |
 392                         (*(cp+1) & 0x3f);
 393         }
 394         else if ( (*cp & 0xf0) == 0xe0 ) {
 395                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 396                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 397                 *bytes = 3;
 398                 *value = ((*cp & 0x0f) << 12) |
 399                         ((*(cp+1) & 0x3f) << 6) |
 400                         (*(cp+2) & 0x3f);
 401         }
 402         else if ( (*cp & 0xf8) == 0xf0 ) {
 403                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 404                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 405                 if ( (*(cp+3) & 0xc0) != 0x80 ) goto dodefault;
 406                 *bytes = 4;
 407                 *value = ((*cp & 0x07) << 18) |
 408                         ((*(cp+1) & 0x3f) << 12) |
 409                         ((*(cp+2) & 0x3f) << 6) |
 410                         (*(cp+3) & 0x3f);
 411         }
 412         else if ( (*cp & 0xfc) == 0xf8 ) {
 413                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 414                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 415                 if ( (*(cp+3) & 0xc0) != 0x80 ) goto dodefault;
 416                 if ( (*(cp+4) & 0xc0) != 0x80 ) goto dodefault;
 417                 *bytes = 5;
 418                 *value = ((*cp & 0x03) << 24) |
 419                         ((*(cp+1) & 0x3f) << 18) |
 420                         ((*(cp+2) & 0x3f) << 12) |
 421                         ((*(cp+3) & 0x3f) << 6) |
 422                         (*(cp+4) & 0x3f);
 423         }
 424         else if ( (*cp & 0xfe) == 0xfc ) {
 425                 if ( (*(cp+1) & 0xc0) != 0x80 ) goto dodefault;
 426                 if ( (*(cp+2) & 0xc0) != 0x80 ) goto dodefault;
 427                 if ( (*(cp+3) & 0xc0) != 0x80 ) goto dodefault;
 428                 if ( (*(cp+4) & 0xc0) != 0x80 ) goto dodefault;
 429                 if ( (*(cp+5) & 0xc0) != 0x80 ) goto dodefault;
 430                 *bytes = 6;
 431                 *value = ((*cp & 0x01) << 30) |
 432                         ((*(cp+1) & 0x3f) << 24) |
 433                         ((*(cp+2) & 0x3f) << 18) |
 434                         ((*(cp+3) & 0x3f) << 12) |
 435                         ((*(cp+4) & 0x3f) << 6) |
 436                         (*(cp+5) & 0x3f);
 437         }
 438         else {
 439 dodefault:
 440                 *bytes = 1;
 441                 *value = (unsigned char)*cp;
 442         }
 443 }
 444
 445 static
 446 char *
 447 entitize(const char * str)
 448 {
 449         int elen, ecount, nsecount;
 450         entity_types *ep;
 451         const char * cp;
 452         char * p, * tmp, * xstr;
 453
 454         char tmpsub[20];
 455         int bytes = 0;
 456         int value = 0;
 457         ep = stdentities;
 458         elen = ecount = nsecount = 0;
 459
 460         /* figure # of entity replacements and additional size. */
 461         while (ep->text) {
 462                 cp = str;
 463                 while ((cp = strstr(cp, ep->text)) != NULL) {
 464                         elen += strlen(ep->entity) - strlen(ep->text);
 465                         ecount++;
 466                         cp += strlen(ep->text);
 467                 }
 468                 ep++;
 469         }
 470
 471         /* figure the same for other than standard entities (i.e. anything
 472          * that isn't in the range U+0000 to U+007F */
 473         for ( cp = str; *cp; cp++ ) {
 474                 if ( *cp & 0x80 ) {
 475
 476                         utf8_to_int( cp, &bytes, &value );
 477                         cp += bytes-1;
 478                         elen += sprintf( tmpsub, "&#x%x;", value ) - bytes;
 479                         nsecount++;
 480                 }
 481         }
 482
 483         /* enough space for the whole string plus entity replacements, if any */
 484         tmp = g_malloc((strlen(str) + elen + 1));
 485         strcpy(tmp, str);
 486
 487         /* no entity replacements */
 488         if (ecount == 0 && nsecount == 0)
 489                 return (tmp);
 490
 491         if ( ecount != 0 ) {
 492                 for (ep = stdentities; ep->text; ep++) {
 493                         p = tmp;
 494                         while ((p = strstr(p, ep->text)) != NULL) {
 495                                 elen = strlen(ep->entity);
 496
 497                                 xstr = g_strdup(p + strlen(ep->text));
 498
 499                                 strcpy(p, ep->entity);
 500                                 strcpy(p + elen, xstr);
 501
 502                                 g_free(xstr);
 503
 504                                 p += elen;
 505                         }
 506                 }
 507         }
 508
 509         if ( nsecount != 0 ) {
 510                 p = tmp;
 511                 while (*p) {
 512                         if ( *p & 0x80 ) {
 513                                 utf8_to_int( p, &bytes, &value );
 514                                 if ( p[bytes] ) {
 515                                         xstr = g_strdup( p + bytes );
 516                                 }
 517                                 else {
 518                                         xstr = NULL;
 519                                 }
 520                                 sprintf( p, "&#x%x;", value );
 521                                 p = p+strlen(p);
 522                                 if ( xstr ) {
 523                                         strcpy( p, xstr );
 524                                         g_free(xstr);
 525                                 }
 526                         }
 527                         else {
 528                                 p++;
 529                         }
 530                 }
 531         }
 532         return (tmp);
 533 }
 534 /**** end GPSBabel code ****/
 535
 536 /* export GPX */
 537 static void gpx_write_waypoint ( const gchar *name, VikWaypoint *wp, FILE *f )
 538 {
 539   static struct LatLon ll;
 540   gchar *tmp;
 541   vik_coord_to_latlon ( &(wp->coord), &ll );
 542   fprintf ( f, "<wpt lat=\"%f\" lon=\"%f\"%s>\n",
 543                ll.lat, ll.lon, wp->visible ? "" : " hidden=\"hidden\"" );
 544
 545   tmp = entitize ( name );
 546   fprintf ( f, "  <name>%s</name>\n", tmp );
 547   g_free ( tmp);
 548
 549   if ( wp->altitude != VIK_DEFAULT_ALTITUDE )
 550     fprintf ( f, "  <ele>%f</ele>\n", wp->altitude );
 551   if ( wp->comment )
 552   {
 553     tmp = entitize(wp->comment);
 554     fprintf ( f, "  <desc>%s</desc>\n", tmp );
 555     g_free ( tmp );
 556   }
 557   if ( wp->image )
 558   {
 559     tmp = entitize(wp->image);
 560     fprintf ( f, "  <link>%s</link>\n", tmp );
 561     g_free ( tmp );
 562   }
 563   if ( wp->symbol )
 564   {
 565     tmp = entitize(wp->symbol);
 566     fprintf ( f, "  <sym>%s</sym>\n", tmp);
 567     g_free ( tmp );
 568   }
 569
 570   fprintf ( f, "</wpt>\n" );
 571 }
 572
 573 static void gpx_write_trackpoint ( VikTrackpoint *tp, FILE *f )
 574 {
 575   static struct LatLon ll;
 576   static gchar time_buf[30];
 577   vik_coord_to_latlon ( &(tp->coord), &ll );
 578
 579   if ( tp->newsegment )
 580     fprintf ( f, "  </trkseg>\n  <trkseg>\n" );
 581
 582   fprintf ( f, "  <trkpt lat=\"%f\" lon=\"%f\">\n", ll.lat, ll.lon );
 583
 584   if ( tp->altitude != VIK_DEFAULT_ALTITUDE )
 585     fprintf ( f, "    <ele>%f</ele>\n", tp->altitude );
 586   if ( tp->has_timestamp ) {
 587     time_buf [ strftime ( time_buf, sizeof(time_buf)-1, GPX_TIME_FORMAT, localtime(&(tp->timestamp)) ) ] = '\0';
 588     fprintf ( f, "    <time>%s</time>\n", time_buf );
 589   }
 590   fprintf ( f, "  </trkpt>\n" );
 591 }
 592
 593
 594 static void gpx_write_track ( const gchar *name, VikTrack *t, FILE *f )
 595 {
 596   gchar *tmp;
 597   gboolean first_tp_is_newsegment; /* must temporarily make it not so, but we want to restore state. not that it matters. */
 598
 599   tmp = entitize ( name );
 600   fprintf ( f, "<trk%s>\n  <name>%s</name>\n", t->visible ? "" : " hidden=\"hidden\"", tmp );
 601   g_free ( tmp );
 602
 603   if ( t->comment )
 604   {
 605     tmp = entitize ( t->comment );
 606     fprintf ( f, "  <desc>%s</desc>\n", tmp );
 607     g_free ( tmp );
 608   }
 609
 610   fprintf ( f, "  <trkseg>\n" );
 611
 612   if ( t->trackpoints && t->trackpoints->data ) {
 613     first_tp_is_newsegment = VIK_TRACKPOINT(t->trackpoints->data)->newsegment;
 614     VIK_TRACKPOINT(t->trackpoints->data)->newsegment = FALSE; /* so we won't write </trkseg><trkseg> already */
 615   }
 616   g_list_foreach ( t->trackpoints, (GFunc) gpx_write_trackpoint, f );
 617   if ( t->trackpoints && t->trackpoints->data )
 618     VIK_TRACKPOINT(t->trackpoints->data)->newsegment = first_tp_is_newsegment; /* restore state */
 619
 620   fprintf ( f, "</trkseg>\n</trk>\n" );
 621 }
 622
 623 void a_gpx_write_file( VikTrwLayer *vtl, FILE *f )
 624 {
 625   fprintf(f, "<?xml version=\"1.0\"?>\n"
 626           "<gpx version=\"1.0\" creator=\"Viking -- http://viking.sf.net/\"\n"
 627           "xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
 628           "xmlns=\"http://www.topografix.com/GPX/1/0\"\n"
 629           "xsi:schemaLocation=\"http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd\">\n");
 630   g_hash_table_foreach ( vik_trw_layer_get_waypoints ( vtl ), (GHFunc) gpx_write_waypoint, f );
 631   g_hash_table_foreach ( vik_trw_layer_get_tracks ( vtl ), (GHFunc) gpx_write_track, f );
 632   fprintf(f, "</gpx>\n");
 633
 634
 635 }