gpx_document.cpp

Go to the documentation of this file.

/**************************************************************************
 *   Copyright (C) 2010 by David S. Register                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,  USA.         *
 **************************************************************************/
 
#include <wx/datetime.h>
#include <wx/utils.h>
 
#include "model/gpx_document.h"
 
// RFC4122 version 4 compliant random UUIDs generator.
wxString GpxDocument::GetUUID(void) {
  wxString str;
  struct {
    int time_low;
    int time_mid;
    int time_hi_and_version;
    int clock_seq_hi_and_rsv;
    int clock_seq_low;
    int node_hi;
    int node_low;
  } uuid;
 
  uuid.time_low = GetRandomNumber(
      0, 2147483647);  // FIXME: the max should be set to something like
                       // MAXINT32, but it doesn't compile un gcc...
  uuid.time_mid = GetRandomNumber(0, 65535);
  uuid.time_hi_and_version = GetRandomNumber(0, 65535);
  uuid.clock_seq_hi_and_rsv = GetRandomNumber(0, 255);
  uuid.clock_seq_low = GetRandomNumber(0, 255);
  uuid.node_hi = GetRandomNumber(0, 65535);
  uuid.node_low = GetRandomNumber(0, 2147483647);
 
  /* Set the two most significant bits (bits 6 and 7) of the
   * clock_seq_hi_and_rsv to zero and one, respectively. */
  uuid.clock_seq_hi_and_rsv = (uuid.clock_seq_hi_and_rsv & 0x3F) | 0x80;
 
  /* Set the four most significant bits (bits 12 through 15) of the
   * time_hi_and_version field to 4 */
  uuid.time_hi_and_version = (uuid.time_hi_and_version & 0x0fff) | 0x4000;
 
  str.Printf(_T("%08x-%04x-%04x-%02x%02x-%04x%08x"), uuid.time_low,
             uuid.time_mid, uuid.time_hi_and_version, uuid.clock_seq_hi_and_rsv,
             uuid.clock_seq_low, uuid.node_hi, uuid.node_low);
 
  return str;
}
 
void GpxDocument::SeedRandom() {
  /* Fill with random. Miliseconds hopefully good enough for our usage, reading
   * /dev/random would be much better on linux and system guid function on
   * Windows as well */
  wxDateTime x = wxDateTime::UNow();
  long seed = x.GetMillisecond();
  seed *= x.GetTicks();
  srand(seed);
}
 
int GpxDocument::GetRandomNumber(int range_min, int range_max) {
  long u = (long)wxRound(
      ((double)rand() / ((double)(RAND_MAX) + 1) * (range_max - range_min)) +
      range_min);
  return (int)u;
}