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Diffstat (limited to 'src/leveldb/util/crc32c.h')
-rw-r--r-- | src/leveldb/util/crc32c.h | 45 |
1 files changed, 0 insertions, 45 deletions
diff --git a/src/leveldb/util/crc32c.h b/src/leveldb/util/crc32c.h deleted file mode 100644 index 1d7e5c075d..0000000000 --- a/src/leveldb/util/crc32c.h +++ /dev/null @@ -1,45 +0,0 @@ -// Copyright (c) 2011 The LevelDB Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. See the AUTHORS file for names of contributors. - -#ifndef STORAGE_LEVELDB_UTIL_CRC32C_H_ -#define STORAGE_LEVELDB_UTIL_CRC32C_H_ - -#include <stddef.h> -#include <stdint.h> - -namespace leveldb { -namespace crc32c { - -// Return the crc32c of concat(A, data[0,n-1]) where init_crc is the -// crc32c of some string A. Extend() is often used to maintain the -// crc32c of a stream of data. -extern uint32_t Extend(uint32_t init_crc, const char* data, size_t n); - -// Return the crc32c of data[0,n-1] -inline uint32_t Value(const char* data, size_t n) { - return Extend(0, data, n); -} - -static const uint32_t kMaskDelta = 0xa282ead8ul; - -// Return a masked representation of crc. -// -// Motivation: it is problematic to compute the CRC of a string that -// contains embedded CRCs. Therefore we recommend that CRCs stored -// somewhere (e.g., in files) should be masked before being stored. -inline uint32_t Mask(uint32_t crc) { - // Rotate right by 15 bits and add a constant. - return ((crc >> 15) | (crc << 17)) + kMaskDelta; -} - -// Return the crc whose masked representation is masked_crc. -inline uint32_t Unmask(uint32_t masked_crc) { - uint32_t rot = masked_crc - kMaskDelta; - return ((rot >> 17) | (rot << 15)); -} - -} // namespace crc32c -} // namespace leveldb - -#endif // STORAGE_LEVELDB_UTIL_CRC32C_H_ |