1*b0d17251Schristos /* 2*b0d17251Schristos * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved. 3*b0d17251Schristos * 4*b0d17251Schristos * Licensed under the Apache License 2.0 (the "License"). You may not use 5*b0d17251Schristos * this file except in compliance with the License. You can obtain a copy 6*b0d17251Schristos * in the file LICENSE in the source distribution or at 7*b0d17251Schristos * https://www.openssl.org/source/license.html 8*b0d17251Schristos */ 9*b0d17251Schristos 10*b0d17251Schristos #ifndef OSSL_INTERNAL_ENDIAN_H 11*b0d17251Schristos # define OSSL_INTERNAL_ENDIAN_H 12*b0d17251Schristos # pragma once 13*b0d17251Schristos 14*b0d17251Schristos /* 15*b0d17251Schristos * IS_LITTLE_ENDIAN and IS_BIG_ENDIAN can be used to detect the endiannes 16*b0d17251Schristos * at compile time. To use it, DECLARE_IS_ENDIAN must be used to declare 17*b0d17251Schristos * a variable. 18*b0d17251Schristos * 19*b0d17251Schristos * L_ENDIAN and B_ENDIAN can be used at preprocessor time. They can be set 20*b0d17251Schristos * in the configarion using the lib_cppflags variable. If neither is 21*b0d17251Schristos * set, it will fall back to code works with either endianness. 22*b0d17251Schristos */ 23*b0d17251Schristos 24*b0d17251Schristos # if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) 25*b0d17251Schristos # define DECLARE_IS_ENDIAN const int ossl_is_little_endian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ 26*b0d17251Schristos # define IS_LITTLE_ENDIAN (ossl_is_little_endian) 27*b0d17251Schristos # define IS_BIG_ENDIAN (!ossl_is_little_endian) 28*b0d17251Schristos # if defined(L_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) 29*b0d17251Schristos # error "L_ENDIAN defined on a big endian machine" 30*b0d17251Schristos # endif 31*b0d17251Schristos # if defined(B_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 32*b0d17251Schristos # error "B_ENDIAN defined on a little endian machine" 33*b0d17251Schristos # endif 34*b0d17251Schristos # if !defined(L_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 35*b0d17251Schristos # define L_ENDIAN 36*b0d17251Schristos # endif 37*b0d17251Schristos # if !defined(B_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) 38*b0d17251Schristos # define B_ENDIAN 39*b0d17251Schristos # endif 40*b0d17251Schristos # else 41*b0d17251Schristos # define DECLARE_IS_ENDIAN \ 42*b0d17251Schristos const union { \ 43*b0d17251Schristos long one; \ 44*b0d17251Schristos char little; \ 45*b0d17251Schristos } ossl_is_endian = { 1 } 46*b0d17251Schristos 47*b0d17251Schristos # define IS_LITTLE_ENDIAN (ossl_is_endian.little != 0) 48*b0d17251Schristos # define IS_BIG_ENDIAN (ossl_is_endian.little == 0) 49*b0d17251Schristos # endif 50*b0d17251Schristos 51*b0d17251Schristos #endif 52