Mirror of BoringSSL (grpc依赖)
https://boringssl.googlesource.com/boringssl
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65 lines
2.2 KiB
65 lines
2.2 KiB
/* Copyright (c) 2015, Google Inc. |
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* |
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* Permission to use, copy, modify, and/or distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ |
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#include "internal.h" |
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#if defined(OPENSSL_C11_ATOMIC) |
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#include <assert.h> |
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#include <stdalign.h> |
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#include <stdatomic.h> |
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#include <stdlib.h> |
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// See comment above the typedef of CRYPTO_refcount_t about these tests. |
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static_assert(alignof(CRYPTO_refcount_t) == alignof(_Atomic CRYPTO_refcount_t), |
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"_Atomic alters the needed alignment of a reference count"); |
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static_assert(sizeof(CRYPTO_refcount_t) == sizeof(_Atomic CRYPTO_refcount_t), |
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"_Atomic alters the size of a reference count"); |
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static_assert((CRYPTO_refcount_t)-1 == CRYPTO_REFCOUNT_MAX, |
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"CRYPTO_REFCOUNT_MAX is incorrect"); |
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void CRYPTO_refcount_inc(CRYPTO_refcount_t *in_count) { |
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_Atomic CRYPTO_refcount_t *count = (_Atomic CRYPTO_refcount_t *) in_count; |
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uint32_t expected = atomic_load(count); |
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while (expected != CRYPTO_REFCOUNT_MAX) { |
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uint32_t new_value = expected + 1; |
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if (atomic_compare_exchange_weak(count, &expected, new_value)) { |
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break; |
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} |
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} |
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} |
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int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *in_count) { |
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_Atomic CRYPTO_refcount_t *count = (_Atomic CRYPTO_refcount_t *)in_count; |
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uint32_t expected = atomic_load(count); |
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for (;;) { |
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if (expected == 0) { |
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abort(); |
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} else if (expected == CRYPTO_REFCOUNT_MAX) { |
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return 0; |
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} else { |
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const uint32_t new_value = expected - 1; |
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if (atomic_compare_exchange_weak(count, &expected, new_value)) { |
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return new_value == 0; |
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} |
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} |
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} |
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} |
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#endif // OPENSSL_C11_ATOMIC
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