/* Hardware capability support for run-time dynamic loader.  String splitting.

   Copyright (C) 2020 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C 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.

   The GNU C 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 the GNU C Library; if not, see

   <https://www.gnu.org/licenses/>.  */

#include <dl-hwcaps.h>

#include <stdbool.h>

#include <string.h>

_Bool

_dl_hwcaps_split (struct dl_hwcaps_split *s)

{

  if (s->segment == NULL)

    return false;

  /* Skip over the previous segment.   */

  s->segment += s->length;

  /* Consume delimiters.  This also avoids returning an empty

     segment.  */

  while (*s->segment == ':')

    ++s->segment;

  if (*s->segment == '\0')

    return false;

  /* This could use strchrnul, but we would have to link the function

     into ld.so for that.  */

  const char *colon = strchr (s->segment, ':');

  if (colon == NULL)

    s->length = strlen (s->segment);

  else

    s->length = colon - s->segment;

  return true;

}

_Bool

_dl_hwcaps_split_masked (struct dl_hwcaps_split_masked *s)

{

  while (true)

    {

      if (!_dl_hwcaps_split (&s->split))

        return false;

      bool active = s->bitmask & 1;

      s->bitmask >>= 1;

      if (active && _dl_hwcaps_contains (s->mask,

                                         s->split.segment, s->split.length))

        return true;

    }

}

_Bool

_dl_hwcaps_contains (const char *hwcaps, const char *name, size_t name_length)

{

  if (hwcaps == NULL)

    return true;

  struct dl_hwcaps_split split;

  _dl_hwcaps_split_init (&split, hwcaps);

  while (_dl_hwcaps_split (&split))

    if (split.length == name_length

        && memcmp (split.segment, name, name_length) == 0)

      return true;

  return false;

}