/********************************************************************************
*                                                                               *
*                                T i m e   S t u f f                            *
*                                                                               *
*********************************************************************************
* Copyright (C) 2019,2026 by Jeroen van der Zijp.   All Rights Reserved.        *
*********************************************************************************
* This library is free software; you can redistribute it and/or modify          *
* it under the terms of the GNU Lesser General Public License as published by   *
* the Free Software Foundation; either version 3 of the License, or             *
* (at your option) any later version.                                           *
*                                                                               *
* This library 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 Lesser General Public License for more details.                           *
*                                                                               *
* You should have received a copy of the GNU Lesser General Public License      *
* along with this program.  If not, see <http://www.gnu.org/licenses/>          *
********************************************************************************/
#include "xincs.h"
#include "fxver.h"
#include "fxdefs.h"
#include "FXString.h"
#include "FXSystem.h"


/*
  Notes:
  - Return number of leap seconds from utc or tai (nanoseconds) since Unix Epoch.
  - Leap seconds date may be obtained from International Earth Rotation
    System (www.iers.org), Bulletin C.  At the time of this writing,
    https://datacenter.iers.org/data/16/bulletinc-059.txt.
  - List of leap seconds is obtained from IETF,
    https://www.ietf.org/timezones/data/leap-seconds.list.
  - When new leap seconds are announced by IERS, leapsecond table must be
    appended with a new entry; please notify jeroen@fox-toolkit.net if new
    data is available but not yet incorporated into "leapseconds.h".
  - We only remember *when* the leap seconds happen; the index in the array
    tells us how many leap seconds there were up to that time (just add 10,
    since when leap seconds were first applied, there were 10 of them).
*/


using namespace FX;

/*******************************************************************************/

namespace FX {

#include "leapseconds.h"

// Return leap seconds from utc in nanocseconds since Unix Epoch
FXival FXSystem::leapSeconds(FXTime utc){
  FXival l=0,h=ARRAYNUMBER(leapseconds_utc)-1,m;
  if(leapseconds_utc[h]<=utc) return h+10;
  if(utc<leapseconds_utc[l]) return 0;
  while(l<(m=(h+l)>>1)){
    if(leapseconds_utc[m]<=utc) l=m; else h=m;
    }
  return l+10;
  }


// Return leap seconds from tai in nanocseconds since Unix Epoch
FXival FXSystem::leapSecondsTAI(FXTime tai){
  FXival l=0,h=ARRAYNUMBER(leapseconds_tai)-1,m;
  if(leapseconds_tai[h]<=tai) return h+10;
  if(tai<leapseconds_tai[l]) return 0;
  while(l<(m=(h+l)>>1)){
    if(leapseconds_tai[m]<=tai) l=m; else h=m;
    }
  return l+10;
  }

}

