/* Copyright (C) 2008  Emmanuel Varoquaux

   This file is part of XOS.

   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 3 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, see <http://www.gnu.org/licenses/>. */

#include "unistd.h"

#include "xos.h"

static void *curbrk = (void *)-1;

static void init_curbrk()
{
  __syscall_sbrk(0, &curbrk);
}

static int sbrk_internal(int incr)
{
  void *_brk;

  if (__syscall_sbrk(incr, &_brk) == -1)
    return -1;
  curbrk = _brk;
  return 0;
}

int __attribute__ ((weak, visibility ("default"))) brk(void *addr)
{
  if (curbrk == (void *)-1)
    init_curbrk();

  return sbrk_internal(addr - curbrk);
}
typeof (brk) __brk __attribute__ ((alias ("brk")));

void __attribute__ ((weak, visibility ("default"))) *sbrk(intptr_t incr)
{
  void *oldbrk;

  if (curbrk == (void *)-1)
    init_curbrk();

  if (incr == 0)
    return curbrk;

  oldbrk = curbrk;
  if (sbrk_internal(incr) == -1)
    return (void *)-1;
  return oldbrk;
}
typeof (sbrk) __sbrk __attribute__ ((alias ("sbrk")));