crc32c.h 1.2 KB

123456789101112131415161718192021222324252627282930313233343536373839
  1. // Copyright 2022 The Abseil Authors
  2. //
  3. // Licensed under the Apache License, Version 2.0 (the "License");
  4. // you may not use this file except in compliance with the License.
  5. // You may obtain a copy of the License at
  6. //
  7. // https://www.apache.org/licenses/LICENSE-2.0
  8. //
  9. // Unless required by applicable law or agreed to in writing, software
  10. // distributed under the License is distributed on an "AS IS" BASIS,
  11. // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12. // See the License for the specific language governing permissions and
  13. // limitations under the License.
  14. #ifndef ABSL_CRC_INTERNAL_CRC32C_H_
  15. #define ABSL_CRC_INTERNAL_CRC32C_H_
  16. #include "absl/base/config.h"
  17. #include "absl/crc/crc32c.h"
  18. namespace absl {
  19. ABSL_NAMESPACE_BEGIN
  20. namespace crc_internal {
  21. // Modifies a CRC32 value by removing `length` bytes with a value of 0 from
  22. // the end of the string.
  23. //
  24. // This is the inverse operation of ExtendCrc32cByZeroes().
  25. //
  26. // This operation has a runtime cost of O(log(`length`))
  27. //
  28. // Internal implementation detail, exposed for testing only.
  29. crc32c_t UnextendCrc32cByZeroes(crc32c_t initial_crc, size_t length);
  30. } // namespace crc_internal
  31. ABSL_NAMESPACE_END
  32. } // namespace absl
  33. #endif // ABSL_CRC_INTERNAL_CRC32C_H_