1  /* Interface to byteswapping functions.
       2     Copyright (C) 2006-2023 Free Software Foundation, Inc.
       3  
       4     This file is part of libctf.
       5  
       6     libctf is free software; you can redistribute it and/or modify it under
       7     the terms of the GNU General Public License as published by the Free
       8     Software Foundation; either version 3, or (at your option) any later
       9     version.
      10  
      11     This program is distributed in the hope that it will be useful, but
      12     WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
      14     See the 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; see the file COPYING.  If not see
      18     <http://www.gnu.org/licenses/>.  */
      19  
      20  #ifndef _CTF_SWAP_H
      21  #define _CTF_SWAP_H
      22  
      23  #include "config.h"
      24  #include <stdint.h>
      25  #include <assert.h>
      26  
      27  #ifdef HAVE_BYTESWAP_H
      28  #include <byteswap.h>
      29  #endif /* defined(HAVE_BYTESWAP_H) */
      30  
      31  /* Provide our own versions of the byteswap functions.  */
      32  
      33  #if !HAVE_DECL_BSWAP_16
      34  static inline uint16_t
      35  bswap_16 (uint16_t v)
      36  {
      37    return ((v >> 8) & 0xff) | ((v & 0xff) << 8);
      38  }
      39  #endif /* !HAVE_DECL_BSWAP16 */
      40  
      41  #if !HAVE_DECL_BSWAP_32
      42  static inline uint32_t
      43  bswap_32 (uint32_t v)
      44  {
      45    return (  ((v & 0xff000000) >> 24)
      46  	  | ((v & 0x00ff0000) >>  8)
      47  	  | ((v & 0x0000ff00) <<  8)
      48  	  | ((v & 0x000000ff) << 24));
      49  }
      50  #endif /* !HAVE_DECL_BSWAP32 */
      51  
      52  #if !HAVE_DECL_BSWAP_64
      53  static inline uint64_t
      54  bswap_64 (uint64_t v)
      55  {
      56    return (  ((v & 0xff00000000000000ULL) >> 56)
      57  	  | ((v & 0x00ff000000000000ULL) >> 40)
      58  	  | ((v & 0x0000ff0000000000ULL) >> 24)
      59  	  | ((v & 0x000000ff00000000ULL) >>  8)
      60  	  | ((v & 0x00000000ff000000ULL) <<  8)
      61  	  | ((v & 0x0000000000ff0000ULL) << 24)
      62  	  | ((v & 0x000000000000ff00ULL) << 40)
      63  	  | ((v & 0x00000000000000ffULL) << 56));
      64  }
      65  #endif /* !HAVE_DECL_BSWAP64 */
      66  
      67  /* < C11? define away static assertions.  */
      68  
      69  #if !defined (__STDC_VERSION__) || __STDC_VERSION__ < 201112L
      70  #define _Static_assert(cond, err)
      71  #endif
      72  
      73  /* Swap the endianness of something.  */
      74  
      75  #define swap_thing(x)							\
      76    do									\
      77      {									\
      78        _Static_assert (sizeof (x) == 1 || (sizeof (x) % 2 == 0		\
      79  					  && sizeof (x) <= 8),		\
      80  		      "Invalid size, update endianness code");		\
      81        switch (sizeof (x)) {						\
      82        case 2: x = bswap_16 (x); break;					\
      83        case 4: x = bswap_32 (x); break;					\
      84        case 8: x = bswap_64 (x); break;					\
      85        case 1: /* Nothing needs doing */					\
      86  	break;								\
      87        }									\
      88      }									\
      89    while (0);
      90  
      91  
      92  #endif /* !defined(_CTF_SWAP_H) */