1*b077aed3SPierre Pronchery /* 2*b077aed3SPierre Pronchery * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved. 3*b077aed3SPierre Pronchery * 4*b077aed3SPierre Pronchery * Licensed under the Apache License 2.0 (the "License"). You may not use 5*b077aed3SPierre Pronchery * this file except in compliance with the License. You can obtain a copy 6*b077aed3SPierre Pronchery * in the file LICENSE in the source distribution or at 7*b077aed3SPierre Pronchery * https://www.openssl.org/source/license.html 8*b077aed3SPierre Pronchery */ 9*b077aed3SPierre Pronchery 10*b077aed3SPierre Pronchery #ifndef OSSL_INTERNAL_ENDIAN_H 11*b077aed3SPierre Pronchery # define OSSL_INTERNAL_ENDIAN_H 12*b077aed3SPierre Pronchery # pragma once 13*b077aed3SPierre Pronchery 14*b077aed3SPierre Pronchery /* 15*b077aed3SPierre Pronchery * IS_LITTLE_ENDIAN and IS_BIG_ENDIAN can be used to detect the endiannes 16*b077aed3SPierre Pronchery * at compile time. To use it, DECLARE_IS_ENDIAN must be used to declare 17*b077aed3SPierre Pronchery * a variable. 18*b077aed3SPierre Pronchery * 19*b077aed3SPierre Pronchery * L_ENDIAN and B_ENDIAN can be used at preprocessor time. They can be set 20*b077aed3SPierre Pronchery * in the configarion using the lib_cppflags variable. If neither is 21*b077aed3SPierre Pronchery * set, it will fall back to code works with either endianness. 22*b077aed3SPierre Pronchery */ 23*b077aed3SPierre Pronchery 24*b077aed3SPierre Pronchery # if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) 25*b077aed3SPierre Pronchery # define DECLARE_IS_ENDIAN const int ossl_is_little_endian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ 26*b077aed3SPierre Pronchery # define IS_LITTLE_ENDIAN (ossl_is_little_endian) 27*b077aed3SPierre Pronchery # define IS_BIG_ENDIAN (!ossl_is_little_endian) 28*b077aed3SPierre Pronchery # if defined(L_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) 29*b077aed3SPierre Pronchery # error "L_ENDIAN defined on a big endian machine" 30*b077aed3SPierre Pronchery # endif 31*b077aed3SPierre Pronchery # if defined(B_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 32*b077aed3SPierre Pronchery # error "B_ENDIAN defined on a little endian machine" 33*b077aed3SPierre Pronchery # endif 34*b077aed3SPierre Pronchery # if !defined(L_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 35*b077aed3SPierre Pronchery # define L_ENDIAN 36*b077aed3SPierre Pronchery # endif 37*b077aed3SPierre Pronchery # if !defined(B_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__) 38*b077aed3SPierre Pronchery # define B_ENDIAN 39*b077aed3SPierre Pronchery # endif 40*b077aed3SPierre Pronchery # else 41*b077aed3SPierre Pronchery # define DECLARE_IS_ENDIAN \ 42*b077aed3SPierre Pronchery const union { \ 43*b077aed3SPierre Pronchery long one; \ 44*b077aed3SPierre Pronchery char little; \ 45*b077aed3SPierre Pronchery } ossl_is_endian = { 1 } 46*b077aed3SPierre Pronchery 47*b077aed3SPierre Pronchery # define IS_LITTLE_ENDIAN (ossl_is_endian.little != 0) 48*b077aed3SPierre Pronchery # define IS_BIG_ENDIAN (ossl_is_endian.little == 0) 49*b077aed3SPierre Pronchery # endif 50*b077aed3SPierre Pronchery 51*b077aed3SPierre Pronchery #endif 52