250 lines
8.4 KiB
C
250 lines
8.4 KiB
C
/**
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* \file common.h
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*
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* \brief Utility macros for internal use in the library
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*/
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/*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBEDTLS_LIBRARY_COMMON_H
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#define MBEDTLS_LIBRARY_COMMON_H
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#include "mbedtls/build_info.h"
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#include "alignment.h"
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#include <assert.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stddef.h>
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#if defined(__ARM_NEON)
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#include <arm_neon.h>
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#endif /* __ARM_NEON */
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/** Helper to define a function as static except when building invasive tests.
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*
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* If a function is only used inside its own source file and should be
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* declared `static` to allow the compiler to optimize for code size,
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* but that function has unit tests, define it with
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* ```
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* MBEDTLS_STATIC_TESTABLE int mbedtls_foo(...) { ... }
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* ```
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* and declare it in a header in the `library/` directory with
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* ```
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* #if defined(MBEDTLS_TEST_HOOKS)
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* int mbedtls_foo(...);
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* #endif
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* ```
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*/
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#if defined(MBEDTLS_TEST_HOOKS)
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#define MBEDTLS_STATIC_TESTABLE
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#else
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#define MBEDTLS_STATIC_TESTABLE static
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#endif
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#if defined(MBEDTLS_TEST_HOOKS)
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extern void (*mbedtls_test_hook_test_fail)(const char *test, int line, const char *file);
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#define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST) \
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do { \
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if ((!(TEST)) && ((*mbedtls_test_hook_test_fail) != NULL)) \
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{ \
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(*mbedtls_test_hook_test_fail)( #TEST, __LINE__, __FILE__); \
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} \
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} while (0)
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#else
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#define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST)
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#endif /* defined(MBEDTLS_TEST_HOOKS) */
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/** Allow library to access its structs' private members.
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*
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* Although structs defined in header files are publicly available,
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* their members are private and should not be accessed by the user.
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*/
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#define MBEDTLS_ALLOW_PRIVATE_ACCESS
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/** Return an offset into a buffer.
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*
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* This is just the addition of an offset to a pointer, except that this
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* function also accepts an offset of 0 into a buffer whose pointer is null.
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* (`p + n` has undefined behavior when `p` is null, even when `n == 0`.
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* A null pointer is a valid buffer pointer when the size is 0, for example
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* as the result of `malloc(0)` on some platforms.)
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*
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* \param p Pointer to a buffer of at least n bytes.
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* This may be \p NULL if \p n is zero.
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* \param n An offset in bytes.
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* \return Pointer to offset \p n in the buffer \p p.
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* Note that this is only a valid pointer if the size of the
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* buffer is at least \p n + 1.
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*/
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static inline unsigned char *mbedtls_buffer_offset(
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unsigned char *p, size_t n)
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{
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return p == NULL ? NULL : p + n;
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}
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/** Return an offset into a read-only buffer.
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*
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* Similar to mbedtls_buffer_offset(), but for const pointers.
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*
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* \param p Pointer to a buffer of at least n bytes.
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* This may be \p NULL if \p n is zero.
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* \param n An offset in bytes.
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* \return Pointer to offset \p n in the buffer \p p.
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* Note that this is only a valid pointer if the size of the
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* buffer is at least \p n + 1.
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*/
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static inline const unsigned char *mbedtls_buffer_offset_const(
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const unsigned char *p, size_t n)
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{
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return p == NULL ? NULL : p + n;
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}
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/**
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* Perform a fast block XOR operation, such that
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* r[i] = a[i] ^ b[i] where 0 <= i < n
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*
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* \param r Pointer to result (buffer of at least \p n bytes). \p r
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* may be equal to either \p a or \p b, but behaviour when
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* it overlaps in other ways is undefined.
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* \param a Pointer to input (buffer of at least \p n bytes)
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* \param b Pointer to input (buffer of at least \p n bytes)
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* \param n Number of bytes to process.
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*/
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inline void mbedtls_xor(unsigned char *r, const unsigned char *a, const unsigned char *b, size_t n)
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{
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size_t i = 0;
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#if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS)
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#if defined(__ARM_NEON)
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for (; (i + 16) <= n; i += 16) {
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uint8x16_t v1 = vld1q_u8(a + i);
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uint8x16_t v2 = vld1q_u8(b + i);
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uint8x16_t x = veorq_u8(v1, v2);
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vst1q_u8(r + i, x);
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}
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#elif defined(__amd64__) || defined(__x86_64__) || defined(__aarch64__)
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/* This codepath probably only makes sense on architectures with 64-bit registers */
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for (; (i + 8) <= n; i += 8) {
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uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);
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mbedtls_put_unaligned_uint64(r + i, x);
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}
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#else
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for (; (i + 4) <= n; i += 4) {
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uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i);
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mbedtls_put_unaligned_uint32(r + i, x);
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}
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#endif
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#endif
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for (; i < n; i++) {
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r[i] = a[i] ^ b[i];
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}
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}
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/**
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* Perform a fast block XOR operation, such that
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* r[i] = a[i] ^ b[i] where 0 <= i < n
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*
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* In some situations, this can perform better than mbedtls_xor (e.g., it's about 5%
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* better in AES-CBC).
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*
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* \param r Pointer to result (buffer of at least \p n bytes). \p r
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* may be equal to either \p a or \p b, but behaviour when
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* it overlaps in other ways is undefined.
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* \param a Pointer to input (buffer of at least \p n bytes)
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* \param b Pointer to input (buffer of at least \p n bytes)
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* \param n Number of bytes to process.
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*/
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static inline void mbedtls_xor_no_simd(unsigned char *r,
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const unsigned char *a,
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const unsigned char *b,
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size_t n)
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{
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size_t i = 0;
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#if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS)
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#if defined(__amd64__) || defined(__x86_64__) || defined(__aarch64__)
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/* This codepath probably only makes sense on architectures with 64-bit registers */
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for (; (i + 8) <= n; i += 8) {
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uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);
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mbedtls_put_unaligned_uint64(r + i, x);
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}
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#else
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for (; (i + 4) <= n; i += 4) {
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uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i);
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mbedtls_put_unaligned_uint32(r + i, x);
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}
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#endif
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#endif
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for (; i < n; i++) {
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r[i] = a[i] ^ b[i];
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}
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}
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/* Fix MSVC C99 compatible issue
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* MSVC support __func__ from visual studio 2015( 1900 )
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* Use MSVC predefine macro to avoid name check fail.
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*/
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#if (defined(_MSC_VER) && (_MSC_VER <= 1900))
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#define /*no-check-names*/ __func__ __FUNCTION__
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#endif
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/* Define `asm` for compilers which don't define it. */
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/* *INDENT-OFF* */
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#ifndef asm
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#define asm __asm__
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#endif
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/* *INDENT-ON* */
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/* Always provide a static assert macro, so it can be used unconditionally.
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* It will expand to nothing on some systems.
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* Can be used outside functions (but don't add a trailing ';' in that case:
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* the semicolon is included here to avoid triggering -Wextra-semi when
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* MBEDTLS_STATIC_ASSERT() expands to nothing).
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* Can't use the C11-style `defined(static_assert)` on FreeBSD, since it
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* defines static_assert even with -std=c99, but then complains about it.
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*/
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#if defined(static_assert) && !defined(__FreeBSD__)
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#define MBEDTLS_STATIC_ASSERT(expr, msg) static_assert(expr, msg);
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#else
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#define MBEDTLS_STATIC_ASSERT(expr, msg)
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#endif
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/* Define compiler branch hints */
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#if defined(__has_builtin)
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#if __has_builtin(__builtin_expect)
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#define MBEDTLS_LIKELY(x) __builtin_expect((x), 1)
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#define MBEDTLS_UNLIKELY(x) __builtin_expect((x), 0)
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#endif
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#endif
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#if !defined(MBEDTLS_LIKELY)
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#define MBEDTLS_LIKELY(x) x
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#define MBEDTLS_UNLIKELY(x) x
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#endif
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#if defined(__GNUC__) && !defined(__ARMCC_VERSION) && !defined(__clang__) \
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&& !defined(__llvm__) && !defined(__INTEL_COMPILER)
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/* Defined if the compiler really is gcc and not clang, etc */
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#define MBEDTLS_COMPILER_IS_GCC
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#endif
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/* If -Os is specified, override with -O2 for a given function */
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#if defined(MBEDTLS_COMPILER_IS_GCC) && defined(__OPTIMIZE_SIZE__)
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#define MBEDTLS_OPTIMIZE_ALWAYS __attribute__((optimize("-O2")))
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#else
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#define MBEDTLS_OPTIMIZE_ALWAYS
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#endif
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#endif /* MBEDTLS_LIBRARY_COMMON_H */
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