// Copyright 2015 The BoringSSL Authors

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include "internal.h"

#include <assert.h>

#include <stdlib.h>

void CRYPTO_refcount_inc(CRYPTO_refcount_t *count) {

  uint32_t expected = CRYPTO_atomic_load_u32(count);

  while (expected != CRYPTO_REFCOUNT_MAX) {

    uint32_t new_value = expected + 1;

    if (CRYPTO_atomic_compare_exchange_weak_u32(count, &expected, new_value)) {

      break;

    }

  }

}

int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *count) {

  uint32_t expected = CRYPTO_atomic_load_u32(count);

  for (;;) {

    if (expected == 0) {

      abort();

    } else if (expected == CRYPTO_REFCOUNT_MAX) {

      return 0;

    } else {

      const uint32_t new_value = expected - 1;

      if (CRYPTO_atomic_compare_exchange_weak_u32(count, &expected,

                                                  new_value)) {

        return new_value == 0;

      }

    }

  }

}