libjaylink/util.c

   1 /*
   2  * This file is part of the libjaylink project.
   3  *
   4  * Copyright (C) 2014-2015 Marc Schink <jaylink-dev@marcschink.de>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "libjaylink.h"
  21
  22 /**
  23  * @file
  24  *
  25  * Utility functions.
  26  */
  27
  28 /**
  29  * Check for a capability.
  30  *
  31  * The capabilities are expected to be stored in a bit array consisting of one
  32  * or more bytes where each individual bit represents a capability. The first
  33  * bit of this array is the least significant bit of the first byte and the
  34  * following bits are sequentially numbered in order of increasing bit
  35  * significance and byte index. A set bit indicates a supported capability.
  36  *
  37  * @param[in] caps Buffer with capabilities.
  38  * @param[in] cap Bit position of the capability to check for.
  39  *
  40  * @return 1 if the capability is supported, 0 otherwise.
  41  */
  42 JAYLINK_API int jaylink_has_cap(const uint8_t *caps, uint32_t cap)
  43 {
  44         if (!caps)
  45                 return 0;
  46
  47         if (caps[cap / 8] & (1 << (cap % 8)))
  48                 return 1;
  49
  50         return 0;
  51 }