/*

  This file is part of libmicrohttpd

  Copyright (C) 2014-2016 Karlson2k (Evgeny Grin)

  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 2.1 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 library; if not, write to the Free Software

  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

*/

/**

 * @file microhttpd/mhd_compat.c

 * @brief  Implementation of platform missing functions.

 * @author Karlson2k (Evgeny Grin)

 */

#include "mhd_compat.h"

#if defined(_WIN32) && !defined(__CYGWIN__)

#include <stdint.h>

#include <time.h>

#ifndef HAVE_SNPRINTF

#include <stdio.h>

#include <stdarg.h>

#endif  /* HAVE_SNPRINTF */

#endif /* _WIN32  && !__CYGWIN__ */

#ifndef HAVE_CALLOC

#include <string.h> /* for memset() */

#endif /* ! HAVE_CALLOC */

#if defined(_WIN32) && !defined(__CYGWIN__)

#ifndef HAVE_SNPRINTF

/* Emulate snprintf function on W32 */

int

W32_snprintf (char *__restrict s,

              size_t n,

              const char *__restrict format,

              ...)

{

  int ret;

  va_list args;

  if ( (0 != n) &&

       (NULL != s) )

  {

    va_start (args,

              format);

    ret = _vsnprintf (s,

                      n,

                      format,

                      args);

    va_end (args);

    if ((int)n == ret)

      s[n - 1] = 0;

    if (ret >= 0)

      return ret;

  }

  va_start(args,

           format);

  ret = _vscprintf (format,

                    args);

  va_end(args);

  if ( (0 <= ret) &&

       (0 != n) &&

       (NULL == s) )

    return -1;

  return ret;

}

#endif  /* HAVE_SNPRINTF */

#endif /* _WIN32  && !__CYGWIN__ */

#ifndef HAVE_CALLOC

#ifdef __has_builtin

#  if __has_builtin(__builtin_mul_overflow)

#    define MHD_HAVE_NUL_OVERFLOW 1

#  endif

#elif __GNUC__+0 >= 5

#  define MHD_HAVE_NUL_OVERFLOW 1

#endif /* __GNUC__ >= 5 */

void *MHD_calloc_(size_t nelem, size_t elsize)

{

  size_t alloc_size;

  void *ptr;

#ifdef MHD_HAVE_NUL_OVERFLOW

  if (__builtin_mul_overflow(nelem, elsize, &alloc_size) || 0 == alloc_size)

    return NULL;

#else  /* ! MHD_HAVE_NUL_OVERFLOW */

  alloc_size = nelem * elsize;

  if (0 == alloc_size || elsize != alloc_size / nelem)

    return NULL;

#endif /* ! MHD_HAVE_NUL_OVERFLOW */

  ptr = malloc (alloc_size);

  if (NULL == ptr)

    return NULL;

  memset(ptr, 0, alloc_size);

  return ptr;

}

#endif /* ! HAVE_CALLOC */