text: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   */
  /* ====================================================================
   * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    openssl-core@openssl.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com). */
  
  #ifndef OPENSSL_HEADER_CRYPTO_INTERNAL_H
  #define OPENSSL_HEADER_CRYPTO_INTERNAL_H
  
  #include <CNIOBoringSSL_crypto.h>
  #include <CNIOBoringSSL_ex_data.h>
  #include <CNIOBoringSSL_stack.h>
  #include <CNIOBoringSSL_thread.h>
  
  #include <assert.h>
  #include <string.h>
  
  #if defined(BORINGSSL_CONSTANT_TIME_VALIDATION)
  #include <valgrind/memcheck.h>
  #endif
  
  #if !defined(__cplusplus)
  #if defined(_MSC_VER)
  #define alignas(x) __declspec(align(x))
  #define alignof __alignof
  #else
  #include <stdalign.h>
  #endif
  #endif
  
  #if defined(OPENSSL_THREADS) && \
      (!defined(OPENSSL_WINDOWS) || defined(__MINGW32__))
  #include <pthread.h>
  #define OPENSSL_PTHREADS
  #endif
  
  #if defined(OPENSSL_THREADS) && !defined(OPENSSL_PTHREADS) && \
      defined(OPENSSL_WINDOWS)
  #define OPENSSL_WINDOWS_THREADS
  OPENSSL_MSVC_PRAGMA(warning(push, 3))
  #include <windows.h>
  OPENSSL_MSVC_PRAGMA(warning(pop))
  #endif
  
  #if defined(__cplusplus)
  extern "C" {
  #endif
  
  
  #if defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || defined(OPENSSL_ARM) || \
      defined(OPENSSL_AARCH64) || defined(OPENSSL_PPC64LE)
  // OPENSSL_cpuid_setup initializes the platform-specific feature cache.
  void OPENSSL_cpuid_setup(void);
  #endif
  
  #if (defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)) && \
      !defined(OPENSSL_STATIC_ARMCAP)
  // OPENSSL_get_armcap_pointer_for_test returns a pointer to |OPENSSL_armcap_P|
  // for unit tests. Any modifications to the value must be made after
  // |CRYPTO_library_init| but before any other function call in BoringSSL.
  OPENSSL_EXPORT uint32_t *OPENSSL_get_armcap_pointer_for_test(void);
  #endif
  
  
  #if (!defined(_MSC_VER) || defined(__clang__)) && defined(OPENSSL_64_BIT)
  #define BORINGSSL_HAS_UINT128
  typedef __int128_t int128_t;
  typedef __uint128_t uint128_t;
  
  // clang-cl supports __uint128_t but modulus and division don't work.
  // https://crbug.com/787617.
  #if !defined(_MSC_VER) || !defined(__clang__)
  #define BORINGSSL_CAN_DIVIDE_UINT128
  #endif
  #endif
  
  #define OPENSSL_ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
  
  // Have a generic fall-through for different versions of C/C++.
  #if defined(__cplusplus) && __cplusplus >= 201703L
  #define OPENSSL_FALLTHROUGH [[fallthrough]]
  #elif defined(__cplusplus) && __cplusplus >= 201103L && defined(__clang__)
  #define OPENSSL_FALLTHROUGH [[clang::fallthrough]]
  #elif defined(__cplusplus) && __cplusplus >= 201103L && defined(__GNUC__) && \
      __GNUC__ >= 7
  #define OPENSSL_FALLTHROUGH [[gnu::fallthrough]]
  #elif defined(__GNUC__) && __GNUC__ >= 7 // gcc 7
  #define OPENSSL_FALLTHROUGH __attribute__ ((fallthrough))
  #elif defined(__clang__)
  #if __has_attribute(fallthrough) && __clang_major__ >= 5
  // Clang 3.5, at least, complains about "error: declaration does not declare
  // anything", possibily because we put a semicolon after this macro in
  // practice. Thus limit it to >= Clang 5, which does work.
  #define OPENSSL_FALLTHROUGH __attribute__ ((fallthrough))
  #else // clang versions that do not support fallthrough.
  #define OPENSSL_FALLTHROUGH
  #endif
  #else // C++11 on gcc 6, and all other cases
  #define OPENSSL_FALLTHROUGH
  #endif
  
  // For convenience in testing 64-bit generic code, we allow disabling SSE2
  // intrinsics via |OPENSSL_NO_SSE2_FOR_TESTING|. x86_64 always has SSE2
  // available, so we would otherwise need to test such code on a non-x86_64
  // platform.
  #if defined(__SSE2__) && !defined(OPENSSL_NO_SSE2_FOR_TESTING)
  #define OPENSSL_SSE2
  #endif
  
  // buffers_alias returns one if |a| and |b| alias and zero otherwise.
  static inline int buffers_alias(const uint8_t *a, size_t a_len,
                                  const uint8_t *b, size_t b_len) {
    // Cast |a| and |b| to integers. In C, pointer comparisons between unrelated
    // objects are undefined whereas pointer to integer conversions are merely
    // implementation-defined. We assume the implementation defined it in a sane
    // way.
    uintptr_t a_u = (uintptr_t)a;
    uintptr_t b_u = (uintptr_t)b;
    return a_u + a_len > b_u && b_u + b_len > a_u;
  }
  
  
  // Constant-time utility functions.
  //
  // The following methods return a bitmask of all ones (0xff...f) for true and 0
  // for false. This is useful for choosing a value based on the result of a
  // conditional in constant time. For example,
  //
  // if (a < b) {
  //   c = a;
  // } else {
  //   c = b;
  // }
  //
  // can be written as
  //
  // crypto_word_t lt = constant_time_lt_w(a, b);
  // c = constant_time_select_w(lt, a, b);
  
  // crypto_word_t is the type that most constant-time functions use. Ideally we
  // would like it to be |size_t|, but NaCl builds in 64-bit mode with 32-bit
  // pointers, which means that |size_t| can be 32 bits when |BN_ULONG| is 64
  // bits. Since we want to be able to do constant-time operations on a
  // |BN_ULONG|, |crypto_word_t| is defined as an unsigned value with the native
  // word length.
  #if defined(OPENSSL_64_BIT)
  typedef uint64_t crypto_word_t;
  #elif defined(OPENSSL_32_BIT)
  typedef uint32_t crypto_word_t;
  #else
  #error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
  #endif
  
  #define CONSTTIME_TRUE_W ~((crypto_word_t)0)
  #define CONSTTIME_FALSE_W ((crypto_word_t)0)
  #define CONSTTIME_TRUE_8 ((uint8_t)0xff)
  #define CONSTTIME_FALSE_8 ((uint8_t)0)
  
  // value_barrier_w returns |a|, but prevents GCC and Clang from reasoning about
  // the returned value. This is used to mitigate compilers undoing constant-time
  // code, until we can express our requirements directly in the language.
  //
  // Note the compiler is aware that |value_barrier_w| has no side effects and
  // always has the same output for a given input. This allows it to eliminate
  // dead code, move computations across loops, and vectorize.
  static inline crypto_word_t value_barrier_w(crypto_word_t a) {
  #if !defined(OPENSSL_NO_ASM) && (defined(__GNUC__) || defined(__clang__))
    __asm__("" : "+r"(a) : /* no inputs */);
  #endif
    return a;
  }
  
  // value_barrier_u32 behaves like |value_barrier_w| but takes a |uint32_t|.
  static inline uint32_t value_barrier_u32(uint32_t a) {
  #if !defined(OPENSSL_NO_ASM) && (defined(__GNUC__) || defined(__clang__))
    __asm__("" : "+r"(a) : /* no inputs */);
  #endif
    return a;
  }
  
  // value_barrier_u64 behaves like |value_barrier_w| but takes a |uint64_t|.
  static inline uint64_t value_barrier_u64(uint64_t a) {
  #if !defined(OPENSSL_NO_ASM) && (defined(__GNUC__) || defined(__clang__))
    __asm__("" : "+r"(a) : /* no inputs */);
  #endif
    return a;
  }
  
  // constant_time_msb_w returns the given value with the MSB copied to all the
  // other bits.
  static inline crypto_word_t constant_time_msb_w(crypto_word_t a) {
    return 0u - (a >> (sizeof(a) * 8 - 1));
  }
  
  // constant_time_lt_w returns 0xff..f if a < b and 0 otherwise.
  static inline crypto_word_t constant_time_lt_w(crypto_word_t a,
                                                 crypto_word_t b) {
    // Consider the two cases of the problem:
    //   msb(a) == msb(b): a < b iff the MSB of a - b is set.
    //   msb(a) != msb(b): a < b iff the MSB of b is set.
    //
    // If msb(a) == msb(b) then the following evaluates as:
    //   msb(a^((a^b)|((a-b)^a))) ==
    //   msb(a^((a-b) ^ a))       ==   (because msb(a^b) == 0)
    //   msb(a^a^(a-b))           ==   (rearranging)
    //   msb(a-b)                      (because ∀x. x^x == 0)
    //
    // Else, if msb(a) != msb(b) then the following evaluates as:
    //   msb(a^((a^b)|((a-b)^a))) ==
    //   msb(a^(𝟙 | ((a-b)^a)))   ==   (because msb(a^b) == 1 and 𝟙
    //                                  represents a value s.t. msb(𝟙) = 1)
    //   msb(a^𝟙)                 ==   (because ORing with 1 results in 1)
    //   msb(b)
    //
    //
    // Here is an SMT-LIB verification of this formula:
    //
    // (define-fun lt ((a (_ BitVec 32)) (b (_ BitVec 32))) (_ BitVec 32)
    //   (bvxor a (bvor (bvxor a b) (bvxor (bvsub a b) a)))
    // )
    //
    // (declare-fun a () (_ BitVec 32))
    // (declare-fun b () (_ BitVec 32))
    //
    // (assert (not (= (= #x00000001 (bvlshr (lt a b) #x0000001f)) (bvult a b))))
    // (check-sat)
    // (get-model)
    return constant_time_msb_w(a^((a^b)|((a-b)^a)));
  }
  
  // constant_time_lt_8 acts like |constant_time_lt_w| but returns an 8-bit
  // mask.
  static inline uint8_t constant_time_lt_8(crypto_word_t a, crypto_word_t b) {
    return (uint8_t)(constant_time_lt_w(a, b));
  }
  
  // constant_time_ge_w returns 0xff..f if a >= b and 0 otherwise.
  static inline crypto_word_t constant_time_ge_w(crypto_word_t a,
                                                 crypto_word_t b) {
    return ~constant_time_lt_w(a, b);
  }
  
  // constant_time_ge_8 acts like |constant_time_ge_w| but returns an 8-bit
  // mask.
  static inline uint8_t constant_time_ge_8(crypto_word_t a, crypto_word_t b) {
    return (uint8_t)(constant_time_ge_w(a, b));
  }
  
  // constant_time_is_zero returns 0xff..f if a == 0 and 0 otherwise.
  static inline crypto_word_t constant_time_is_zero_w(crypto_word_t a) {
    // Here is an SMT-LIB verification of this formula:
    //
    // (define-fun is_zero ((a (_ BitVec 32))) (_ BitVec 32)
    //   (bvand (bvnot a) (bvsub a #x00000001))
    // )
    //
    // (declare-fun a () (_ BitVec 32))
    //
    // (assert (not (= (= #x00000001 (bvlshr (is_zero a) #x0000001f)) (= a #x00000000))))
    // (check-sat)
    // (get-model)
    return constant_time_msb_w(~a & (a - 1));
  }
  
  // constant_time_is_zero_8 acts like |constant_time_is_zero_w| but returns an
  // 8-bit mask.
  static inline uint8_t constant_time_is_zero_8(crypto_word_t a) {
    return (uint8_t)(constant_time_is_zero_w(a));
  }
  
  // constant_time_eq_w returns 0xff..f if a == b and 0 otherwise.
  static inline crypto_word_t constant_time_eq_w(crypto_word_t a,
                                                 crypto_word_t b) {
    return constant_time_is_zero_w(a ^ b);
  }
  
  // constant_time_eq_8 acts like |constant_time_eq_w| but returns an 8-bit
  // mask.
  static inline uint8_t constant_time_eq_8(crypto_word_t a, crypto_word_t b) {
    return (uint8_t)(constant_time_eq_w(a, b));
  }
  
  // constant_time_eq_int acts like |constant_time_eq_w| but works on int
  // values.
  static inline crypto_word_t constant_time_eq_int(int a, int b) {
    return constant_time_eq_w((crypto_word_t)(a), (crypto_word_t)(b));
  }
  
  // constant_time_eq_int_8 acts like |constant_time_eq_int| but returns an 8-bit
  // mask.
  static inline uint8_t constant_time_eq_int_8(int a, int b) {
    return constant_time_eq_8((crypto_word_t)(a), (crypto_word_t)(b));
  }
  
  // constant_time_select_w returns (mask & a) | (~mask & b). When |mask| is all
  // 1s or all 0s (as returned by the methods above), the select methods return
  // either |a| (if |mask| is nonzero) or |b| (if |mask| is zero).
  static inline crypto_word_t constant_time_select_w(crypto_word_t mask,
                                                     crypto_word_t a,
                                                     crypto_word_t b) {
    // Clang recognizes this pattern as a select. While it usually transforms it
    // to a cmov, it sometimes further transforms it into a branch, which we do
    // not want.
    //
    // Adding barriers to both |mask| and |~mask| breaks the relationship between
    // the two, which makes the compiler stick with bitmasks.
    return (value_barrier_w(mask) & a) | (value_barrier_w(~mask) & b);
  }
  
  // constant_time_select_8 acts like |constant_time_select| but operates on
  // 8-bit values.
  static inline uint8_t constant_time_select_8(uint8_t mask, uint8_t a,
                                               uint8_t b) {
    return (uint8_t)(constant_time_select_w(mask, a, b));
  }
  
  // constant_time_select_int acts like |constant_time_select| but operates on
  // ints.
  static inline int constant_time_select_int(crypto_word_t mask, int a, int b) {
    return (int)(constant_time_select_w(mask, (crypto_word_t)(a),
                                        (crypto_word_t)(b)));
  }
  
  #if defined(BORINGSSL_CONSTANT_TIME_VALIDATION)
  
  // CONSTTIME_SECRET takes a pointer and a number of bytes and marks that region
  // of memory as secret. Secret data is tracked as it flows to registers and
  // other parts of a memory. If secret data is used as a condition for a branch,
  // or as a memory index, it will trigger warnings in valgrind.
  #define CONSTTIME_SECRET(x, y) VALGRIND_MAKE_MEM_UNDEFINED(x, y)
  
  // CONSTTIME_DECLASSIFY takes a pointer and a number of bytes and marks that
  // region of memory as public. Public data is not subject to constant-time
  // rules.
  #define CONSTTIME_DECLASSIFY(x, y) VALGRIND_MAKE_MEM_DEFINED(x, y)
  
  #else
  
  #define CONSTTIME_SECRET(x, y)
  #define CONSTTIME_DECLASSIFY(x, y)
  
  #endif  // BORINGSSL_CONSTANT_TIME_VALIDATION
  
  
  // Thread-safe initialisation.
  
  #if !defined(OPENSSL_THREADS)
  typedef uint32_t CRYPTO_once_t;
  #define CRYPTO_ONCE_INIT 0
  #elif defined(OPENSSL_WINDOWS_THREADS)
  typedef INIT_ONCE CRYPTO_once_t;
  #define CRYPTO_ONCE_INIT INIT_ONCE_STATIC_INIT
  #elif defined(OPENSSL_PTHREADS)
  typedef pthread_once_t CRYPTO_once_t;
  #define CRYPTO_ONCE_INIT PTHREAD_ONCE_INIT
  #else
  #error "Unknown threading library"
  #endif
  
  // CRYPTO_once calls |init| exactly once per process. This is thread-safe: if
  // concurrent threads call |CRYPTO_once| with the same |CRYPTO_once_t| argument
  // then they will block until |init| completes, but |init| will have only been
  // called once.
  //
  // The |once| argument must be a |CRYPTO_once_t| that has been initialised with
  // the value |CRYPTO_ONCE_INIT|.
  OPENSSL_EXPORT void CRYPTO_once(CRYPTO_once_t *once, void (*init)(void));
  
  
  // Reference counting.
  
  // Automatically enable C11 atomics if implemented.
  #if !defined(OPENSSL_C11_ATOMIC) && !defined(__STDC_NO_ATOMICS__) && \
      defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
  #define OPENSSL_C11_ATOMIC
  #endif
  
  // CRYPTO_REFCOUNT_MAX is the value at which the reference count saturates.
  #define CRYPTO_REFCOUNT_MAX 0xffffffff
  
  // CRYPTO_refcount_inc atomically increments the value at |*count| unless the
  // value would overflow. It's safe for multiple threads to concurrently call
  // this or |CRYPTO_refcount_dec_and_test_zero| on the same
  // |CRYPTO_refcount_t|.
  OPENSSL_EXPORT void CRYPTO_refcount_inc(CRYPTO_refcount_t *count);
  
  // CRYPTO_refcount_dec_and_test_zero tests the value at |*count|:
  //   if it's zero, it crashes the address space.
  //   if it's the maximum value, it returns zero.
  //   otherwise, it atomically decrements it and returns one iff the resulting
  //       value is zero.
  //
  // It's safe for multiple threads to concurrently call this or
  // |CRYPTO_refcount_inc| on the same |CRYPTO_refcount_t|.
  OPENSSL_EXPORT int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *count);
  
  
  // Locks.
  //
  // Two types of locks are defined: |CRYPTO_MUTEX|, which can be used in
  // structures as normal, and |struct CRYPTO_STATIC_MUTEX|, which can be used as
  // a global lock. A global lock must be initialised to the value
  // |CRYPTO_STATIC_MUTEX_INIT|.
  //
  // |CRYPTO_MUTEX| can appear in public structures and so is defined in
  // thread.h as a structure large enough to fit the real type. The global lock is
  // a different type so it may be initialized with platform initializer macros.
  
  #if !defined(OPENSSL_THREADS)
  struct CRYPTO_STATIC_MUTEX {
    char padding;  // Empty structs have different sizes in C and C++.
  };
  #define CRYPTO_STATIC_MUTEX_INIT { 0 }
  #elif defined(OPENSSL_WINDOWS_THREADS)
  struct CRYPTO_STATIC_MUTEX {
    SRWLOCK lock;
  };
  #define CRYPTO_STATIC_MUTEX_INIT { SRWLOCK_INIT }
  #elif defined(OPENSSL_PTHREADS)
  struct CRYPTO_STATIC_MUTEX {
    pthread_rwlock_t lock;
  };
  #define CRYPTO_STATIC_MUTEX_INIT { PTHREAD_RWLOCK_INITIALIZER }
  #else
  #error "Unknown threading library"
  #endif
  
  // CRYPTO_MUTEX_init initialises |lock|. If |lock| is a static variable, use a
  // |CRYPTO_STATIC_MUTEX|.
  OPENSSL_EXPORT void CRYPTO_MUTEX_init(CRYPTO_MUTEX *lock);
  
  // CRYPTO_MUTEX_lock_read locks |lock| such that other threads may also have a
  // read lock, but none may have a write lock.
  OPENSSL_EXPORT void CRYPTO_MUTEX_lock_read(CRYPTO_MUTEX *lock);
  
  // CRYPTO_MUTEX_lock_write locks |lock| such that no other thread has any type
  // of lock on it.
  OPENSSL_EXPORT void CRYPTO_MUTEX_lock_write(CRYPTO_MUTEX *lock);
  
  // CRYPTO_MUTEX_unlock_read unlocks |lock| for reading.
  OPENSSL_EXPORT void CRYPTO_MUTEX_unlock_read(CRYPTO_MUTEX *lock);
  
  // CRYPTO_MUTEX_unlock_write unlocks |lock| for writing.
  OPENSSL_EXPORT void CRYPTO_MUTEX_unlock_write(CRYPTO_MUTEX *lock);
  
  // CRYPTO_MUTEX_cleanup releases all resources held by |lock|.
  OPENSSL_EXPORT void CRYPTO_MUTEX_cleanup(CRYPTO_MUTEX *lock);
  
  // CRYPTO_STATIC_MUTEX_lock_read locks |lock| such that other threads may also
  // have a read lock, but none may have a write lock. The |lock| variable does
  // not need to be initialised by any function, but must have been statically
  // initialised with |CRYPTO_STATIC_MUTEX_INIT|.
  OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_lock_read(
      struct CRYPTO_STATIC_MUTEX *lock);
  
  // CRYPTO_STATIC_MUTEX_lock_write locks |lock| such that no other thread has
  // any type of lock on it.  The |lock| variable does not need to be initialised
  // by any function, but must have been statically initialised with
  // |CRYPTO_STATIC_MUTEX_INIT|.
  OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_lock_write(
      struct CRYPTO_STATIC_MUTEX *lock);
  
  // CRYPTO_STATIC_MUTEX_unlock_read unlocks |lock| for reading.
  OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_unlock_read(
      struct CRYPTO_STATIC_MUTEX *lock);
  
  // CRYPTO_STATIC_MUTEX_unlock_write unlocks |lock| for writing.
  OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_unlock_write(
      struct CRYPTO_STATIC_MUTEX *lock);
  
  #if defined(__cplusplus)
  extern "C++" {
  
  BSSL_NAMESPACE_BEGIN
  
  namespace internal {
  
  // MutexLockBase is a RAII helper for CRYPTO_MUTEX locking.
  template <void (*LockFunc)(CRYPTO_MUTEX *), void (*ReleaseFunc)(CRYPTO_MUTEX *)>
  class MutexLockBase {
   public:
    explicit MutexLockBase(CRYPTO_MUTEX *mu) : mu_(mu) {
      assert(mu_ != nullptr);
      LockFunc(mu_);
    }
    ~MutexLockBase() { ReleaseFunc(mu_); }
    MutexLockBase(const MutexLockBase<LockFunc, ReleaseFunc> &) = delete;
    MutexLockBase &operator=(const MutexLockBase<LockFunc, ReleaseFunc> &) =
        delete;
  
   private:
    CRYPTO_MUTEX *const mu_;
  };
  
  }  // namespace internal
  
  using MutexWriteLock =
      internal::MutexLockBase<CRYPTO_MUTEX_lock_write, CRYPTO_MUTEX_unlock_write>;
  using MutexReadLock =
      internal::MutexLockBase<CRYPTO_MUTEX_lock_read, CRYPTO_MUTEX_unlock_read>;
  
  BSSL_NAMESPACE_END
  
  }  // extern "C++"
  #endif  // defined(__cplusplus)
  
  
  // Thread local storage.
  
  // thread_local_data_t enumerates the types of thread-local data that can be
  // stored.
  typedef enum {
    OPENSSL_THREAD_LOCAL_ERR = 0,
    OPENSSL_THREAD_LOCAL_RAND,
    OPENSSL_THREAD_LOCAL_FIPS_COUNTERS,
    OPENSSL_THREAD_LOCAL_TEST,
    NUM_OPENSSL_THREAD_LOCALS,
  } thread_local_data_t;
  
  // thread_local_destructor_t is the type of a destructor function that will be
  // called when a thread exits and its thread-local storage needs to be freed.
  typedef void (*thread_local_destructor_t)(void *);
  
  // CRYPTO_get_thread_local gets the pointer value that is stored for the
  // current thread for the given index, or NULL if none has been set.
  OPENSSL_EXPORT void *CRYPTO_get_thread_local(thread_local_data_t value);
  
  // CRYPTO_set_thread_local sets a pointer value for the current thread at the
  // given index. This function should only be called once per thread for a given
  // |index|: rather than update the pointer value itself, update the data that
  // is pointed to.
  //
  // The destructor function will be called when a thread exits to free this
  // thread-local data. All calls to |CRYPTO_set_thread_local| with the same
  // |index| should have the same |destructor| argument. The destructor may be
  // called with a NULL argument if a thread that never set a thread-local
  // pointer for |index|, exits. The destructor may be called concurrently with
  // different arguments.
  //
  // This function returns one on success or zero on error. If it returns zero
  // then |destructor| has been called with |value| already.
  OPENSSL_EXPORT int CRYPTO_set_thread_local(
      thread_local_data_t index, void *value,
      thread_local_destructor_t destructor);
  
  
  // ex_data
  
  typedef struct crypto_ex_data_func_st CRYPTO_EX_DATA_FUNCS;
  
  DECLARE_STACK_OF(CRYPTO_EX_DATA_FUNCS)
  
  // CRYPTO_EX_DATA_CLASS tracks the ex_indices registered for a type which
  // supports ex_data. It should defined as a static global within the module
  // which defines that type.
  typedef struct {
    struct CRYPTO_STATIC_MUTEX lock;
    STACK_OF(CRYPTO_EX_DATA_FUNCS) *meth;
    // num_reserved is one if the ex_data index zero is reserved for legacy
    // |TYPE_get_app_data| functions.
    uint8_t num_reserved;
  } CRYPTO_EX_DATA_CLASS;
  
  #define CRYPTO_EX_DATA_CLASS_INIT {CRYPTO_STATIC_MUTEX_INIT, NULL, 0}
  #define CRYPTO_EX_DATA_CLASS_INIT_WITH_APP_DATA \
      {CRYPTO_STATIC_MUTEX_INIT, NULL, 1}
  
  // CRYPTO_get_ex_new_index allocates a new index for |ex_data_class| and writes
  // it to |*out_index|. Each class of object should provide a wrapper function
  // that uses the correct |CRYPTO_EX_DATA_CLASS|. It returns one on success and
  // zero otherwise.
  OPENSSL_EXPORT int CRYPTO_get_ex_new_index(CRYPTO_EX_DATA_CLASS *ex_data_class,
                                             int *out_index, long argl,
                                             void *argp,
                                             CRYPTO_EX_free *free_func);
  
  // CRYPTO_set_ex_data sets an extra data pointer on a given object. Each class
  // of object should provide a wrapper function.
  OPENSSL_EXPORT int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int index, void *val);
  
  // CRYPTO_get_ex_data returns an extra data pointer for a given object, or NULL
  // if no such index exists. Each class of object should provide a wrapper
  // function.
  OPENSSL_EXPORT void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int index);
  
  // CRYPTO_new_ex_data initialises a newly allocated |CRYPTO_EX_DATA|.
  OPENSSL_EXPORT void CRYPTO_new_ex_data(CRYPTO_EX_DATA *ad);
  
  // CRYPTO_free_ex_data frees |ad|, which is embedded inside |obj|, which is an
  // object of the given class.
  OPENSSL_EXPORT void CRYPTO_free_ex_data(CRYPTO_EX_DATA_CLASS *ex_data_class,
                                          void *obj, CRYPTO_EX_DATA *ad);
  
  
  // Endianness conversions.
  
  #if defined(__GNUC__) && __GNUC__ >= 2
  static inline uint16_t CRYPTO_bswap2(uint16_t x) {
    return __builtin_bswap16(x);
  }
  
  static inline uint32_t CRYPTO_bswap4(uint32_t x) {
    return __builtin_bswap32(x);
  }
  
  static inline uint64_t CRYPTO_bswap8(uint64_t x) {
    return __builtin_bswap64(x);
  }
  #elif defined(_MSC_VER)
  OPENSSL_MSVC_PRAGMA(warning(push, 3))
  #include <stdlib.h>
  OPENSSL_MSVC_PRAGMA(warning(pop))
  #pragma intrinsic(_byteswap_uint64, _byteswap_ulong, _byteswap_ushort)
  static inline uint16_t CRYPTO_bswap2(uint16_t x) {
    return _byteswap_ushort(x);
  }
  
  static inline uint32_t CRYPTO_bswap4(uint32_t x) {
    return _byteswap_ulong(x);
  }
  
  static inline uint64_t CRYPTO_bswap8(uint64_t x) {
    return _byteswap_uint64(x);
  }
  #else
  static inline uint16_t CRYPTO_bswap2(uint16_t x) {
    return (x >> 8) | (x << 8);
  }
  
  static inline uint32_t CRYPTO_bswap4(uint32_t x) {
    x = (x >> 16) | (x << 16);
    x = ((x & 0xff00ff00) >> 8) | ((x & 0x00ff00ff) << 8);
    return x;
  }
  
  static inline uint64_t CRYPTO_bswap8(uint64_t x) {
    return CRYPTO_bswap4(x >> 32) | (((uint64_t)CRYPTO_bswap4(x)) << 32);
  }
  #endif
  
  
  // Language bug workarounds.
  //
  // Most C standard library functions are undefined if passed NULL, even when the
  // corresponding length is zero. This gives them (and, in turn, all functions
  // which call them) surprising behavior on empty arrays. Some compilers will
  // miscompile code due to this rule. See also
  // https://www.imperialviolet.org/2016/06/26/nonnull.html
  //
  // These wrapper functions behave the same as the corresponding C standard
  // functions, but behave as expected when passed NULL if the length is zero.
  //
  // Note |OPENSSL_memcmp| is a different function from |CRYPTO_memcmp|.
  
  // C++ defines |memchr| as a const-correct overload.
  #if defined(__cplusplus)
  extern "C++" {
  
  static inline const void *OPENSSL_memchr(const void *s, int c, size_t n) {
    if (n == 0) {
      return NULL;
    }
  
    return memchr(s, c, n);
  }
  
  static inline void *OPENSSL_memchr(void *s, int c, size_t n) {
    if (n == 0) {
      return NULL;
    }
  
    return memchr(s, c, n);
  }
  
  }  // extern "C++"
  #else  // __cplusplus
  
  static inline void *OPENSSL_memchr(const void *s, int c, size_t n) {
    if (n == 0) {
      return NULL;
    }
  
    return memchr(s, c, n);
  }
  
  #endif  // __cplusplus
  
  static inline int OPENSSL_memcmp(const void *s1, const void *s2, size_t n) {
    if (n == 0) {
      return 0;
    }
  
    return memcmp(s1, s2, n);
  }
  
  static inline void *OPENSSL_memcpy(void *dst, const void *src, size_t n) {
    if (n == 0) {
      return dst;
    }
  
    return memcpy(dst, src, n);
  }
  
  static inline void *OPENSSL_memmove(void *dst, const void *src, size_t n) {
    if (n == 0) {
      return dst;
    }
  
    return memmove(dst, src, n);
  }
  
  static inline void *OPENSSL_memset(void *dst, int c, size_t n) {
    if (n == 0) {
      return dst;
    }
  
    return memset(dst, c, n);
  }
  
  
  // Loads and stores.
  //
  // The following functions load and store sized integers with the specified
  // endianness. They use |memcpy|, and so avoid alignment or strict aliasing
  // requirements on the input and output pointers.
  
  static inline uint32_t CRYPTO_load_u32_le(const void *in) {
    uint32_t v;
    OPENSSL_memcpy(&v, in, sizeof(v));
    return v;
  }
  
  static inline void CRYPTO_store_u32_le(void *out, uint32_t v) {
    OPENSSL_memcpy(out, &v, sizeof(v));
  }
  
  static inline uint32_t CRYPTO_load_u32_be(const void *in) {
    uint32_t v;
    OPENSSL_memcpy(&v, in, sizeof(v));
    return CRYPTO_bswap4(v);
  }
  
  static inline void CRYPTO_store_u32_be(void *out, uint32_t v) {
    v = CRYPTO_bswap4(v);
    OPENSSL_memcpy(out, &v, sizeof(v));
  }
  
  static inline uint64_t CRYPTO_load_u64_be(const void *ptr) {
    uint64_t ret;
    OPENSSL_memcpy(&ret, ptr, sizeof(ret));
    return CRYPTO_bswap8(ret);
  }
  
  static inline void CRYPTO_store_u64_be(void *out, uint64_t v) {
    v = CRYPTO_bswap8(v);
    OPENSSL_memcpy(out, &v, sizeof(v));
  }
  
  static inline crypto_word_t CRYPTO_load_word_le(const void *in) {
    crypto_word_t v;
    OPENSSL_memcpy(&v, in, sizeof(v));
    return v;
  }
  
  static inline void CRYPTO_store_word_le(void *out, crypto_word_t v) {
    OPENSSL_memcpy(out, &v, sizeof(v));
  }
  
  
  // FIPS functions.
  
  #if defined(BORINGSSL_FIPS)
  // BORINGSSL_FIPS_abort is called when a FIPS power-on or continuous test
  // fails. It prevents any further cryptographic operations by the current
  // process.
  void BORINGSSL_FIPS_abort(void) __attribute__((noreturn));
  #endif
  
  // boringssl_fips_self_test runs the FIPS KAT-based self tests. It returns one
  // on success and zero on error. The argument is the integrity hash of the FIPS
  // module and may be used to check and write flag files to suppress duplicate
  // self-tests. If |module_hash_len| is zero then no flag file will be checked
  // nor written and tests will always be run.
  int boringssl_fips_self_test(const uint8_t *module_hash,
                               size_t module_hash_len);
  
  #if defined(BORINGSSL_FIPS_COUNTERS)
  void boringssl_fips_inc_counter(enum fips_counter_t counter);
  #else
  OPENSSL_INLINE void boringssl_fips_inc_counter(enum fips_counter_t counter) {}
  #endif
  
  #if defined(__cplusplus)
  }  // extern C
  #endif
  
  #endif  // OPENSSL_HEADER_CRYPTO_INTERNAL_H
  