text: /*
   * Copyright 2016-2019 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (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
   */
  
  #if defined(_WIN32)
  # include <windows.h>
  #endif
  
  #include <openssl/crypto.h>
  
  #if defined(OPENSSL_THREADS) && !defined(CRYPTO_TDEBUG) && defined(OPENSSL_SYS_WINDOWS)
  
  CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
  {
      CRYPTO_RWLOCK *lock;
  
      if ((lock = OPENSSL_zalloc(sizeof(CRITICAL_SECTION))) == NULL) {
          /* Don't set error, to avoid recursion blowup. */
          return NULL;
      }
  
  #if !defined(_WIN32_WCE)
      /* 0x400 is the spin count value suggested in the documentation */
      if (!InitializeCriticalSectionAndSpinCount(lock, 0x400)) {
          OPENSSL_free(lock);
          return NULL;
      }
  #else
      InitializeCriticalSection(lock);
  #endif
  
      return lock;
  }
  
  int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
  {
      EnterCriticalSection(lock);
      return 1;
  }
  
  int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
  {
      EnterCriticalSection(lock);
      return 1;
  }
  
  int CRYPTO_THREAD_unlock(CRYPTO_RWLOCK *lock)
  {
      LeaveCriticalSection(lock);
      return 1;
  }
  
  void CRYPTO_THREAD_lock_free(CRYPTO_RWLOCK *lock)
  {
      if (lock == NULL)
          return;
  
      DeleteCriticalSection(lock);
      OPENSSL_free(lock);
  
      return;
  }
  
  #  define ONCE_UNINITED     0
  #  define ONCE_ININIT       1
  #  define ONCE_DONE         2
  
  /*
   * We don't use InitOnceExecuteOnce because that isn't available in WinXP which
   * we still have to support.
   */
  int CRYPTO_THREAD_run_once(CRYPTO_ONCE *once, void (*init)(void))
  {
      LONG volatile *lock = (LONG *)once;
      LONG result;
  
      if (*lock == ONCE_DONE)
          return 1;
  
      do {
          result = InterlockedCompareExchange(lock, ONCE_ININIT, ONCE_UNINITED);
          if (result == ONCE_UNINITED) {
              init();
              *lock = ONCE_DONE;
              return 1;
          }
      } while (result == ONCE_ININIT);
  
      return (*lock == ONCE_DONE);
  }
  
  int CRYPTO_THREAD_init_local(CRYPTO_THREAD_LOCAL *key, void (*cleanup)(void *))
  {
      *key = TlsAlloc();
      if (*key == TLS_OUT_OF_INDEXES)
          return 0;
  
      return 1;
  }
  
  void *CRYPTO_THREAD_get_local(CRYPTO_THREAD_LOCAL *key)
  {
      DWORD last_error;
      void *ret;
  
      /*
       * TlsGetValue clears the last error even on success, so that callers may
       * distinguish it successfully returning NULL or failing. It is documented
       * to never fail if the argument is a valid index from TlsAlloc, so we do
       * not need to handle this.
       *
       * However, this error-mangling behavior interferes with the caller's use of
       * GetLastError. In particular SSL_get_error queries the error queue to
       * determine whether the caller should look at the OS's errors. To avoid
       * destroying state, save and restore the Windows error.
       *
       * https://msdn.microsoft.com/en-us/library/windows/desktop/ms686812(v=vs.85).aspx
       */
      last_error = GetLastError();
      ret = TlsGetValue(*key);
      SetLastError(last_error);
      return ret;
  }
  
  int CRYPTO_THREAD_set_local(CRYPTO_THREAD_LOCAL *key, void *val)
  {
      if (TlsSetValue(*key, val) == 0)
          return 0;
  
      return 1;
  }
  
  int CRYPTO_THREAD_cleanup_local(CRYPTO_THREAD_LOCAL *key)
  {
      if (TlsFree(*key) == 0)
          return 0;
  
      return 1;
  }
  
  CRYPTO_THREAD_ID CRYPTO_THREAD_get_current_id(void)
  {
      return GetCurrentThreadId();
  }
  
  int CRYPTO_THREAD_compare_id(CRYPTO_THREAD_ID a, CRYPTO_THREAD_ID b)
  {
      return (a == b);
  }
  
  int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock)
  {
      *ret = InterlockedExchangeAdd(val, amount) + amount;
      return 1;
  }
  
  int openssl_init_fork_handlers(void)
  {
      return 0;
  }
  
  int openssl_get_fork_id(void)
  {
      return 0;
  }
  #endif
  