Files
openssl/include/internal/endian.h
Bob Beck 2fab90bb5e 4.0-POST-CLANG-FORMAT-WEBKIT
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Nikola Pajkovsky <nikolap@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/29242)
2025-12-09 00:28:19 -07:00

52 lines
1.7 KiB
C

/*
* Copyright 2019-2025 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef OSSL_INTERNAL_ENDIAN_H
#define OSSL_INTERNAL_ENDIAN_H
#pragma once
/*
* IS_LITTLE_ENDIAN and IS_BIG_ENDIAN can be used to detect the endianness
* at compile time. To use it, DECLARE_IS_ENDIAN must be used to declare
* a variable.
*
* L_ENDIAN and B_ENDIAN can be used at preprocessor time. They can be set
* in the configarion using the lib_cppflags variable. If neither is
* set, it will fall back to code that works with either endianness.
*/
#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__)
#define DECLARE_IS_ENDIAN const int ossl_is_little_endian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define IS_LITTLE_ENDIAN (ossl_is_little_endian)
#define IS_BIG_ENDIAN (!ossl_is_little_endian)
#if defined(L_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__)
#error "L_ENDIAN defined on a big endian machine"
#endif
#if defined(B_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#error "B_ENDIAN defined on a little endian machine"
#endif
#if !defined(L_ENDIAN) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#define L_ENDIAN
#endif
#if !defined(B_ENDIAN) && (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__)
#define B_ENDIAN
#endif
#else
#define DECLARE_IS_ENDIAN \
const union { \
long one; \
char little; \
} ossl_is_endian = { 1 }
#define IS_LITTLE_ENDIAN (ossl_is_endian.little != 0)
#define IS_BIG_ENDIAN (ossl_is_endian.little == 0)
#endif
#endif