1/* 2 * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10#ifndef OSSL_INTERNAL_ENDIAN_H 11# define OSSL_INTERNAL_ENDIAN_H 12# pragma once 13 14/* 15 * IS_LITTLE_ENDIAN and IS_BIG_ENDIAN can be used to detect the endiannes 16 * at compile time. To use it, DECLARE_IS_ENDIAN must be used to declare 17 * a variable. 18 * 19 * L_ENDIAN and B_ENDIAN can be used at preprocessor time. They can be set 20 * in the configarion using the lib_cppflags variable. If neither is 21 * set, it will fall back to code works with either endianness. 22 */ 23 24# if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) 25# define DECLARE_IS_ENDIAN const int ossl_is_little_endian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ 26# define IS_LITTLE_ENDIAN (ossl_is_little_endian) 27# define IS_BIG_ENDIAN (!ossl_is_little_endian) 28# if defined(L_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) 29# error "L_ENDIAN defined on a big endian machine" 30# endif 31# if defined(B_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 32# error "B_ENDIAN defined on a little endian machine" 33# endif 34# if !defined(L_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 35# define L_ENDIAN 36# endif 37# if !defined(B_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) 38# define B_ENDIAN 39# endif 40# else 41# define DECLARE_IS_ENDIAN \ 42 const union { \ 43 long one; \ 44 char little; \ 45 } ossl_is_endian = { 1 } 46 47# define IS_LITTLE_ENDIAN (ossl_is_endian.little != 0) 48# define IS_BIG_ENDIAN (ossl_is_endian.little == 0) 49# endif 50 51#endif 52