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 15 #ifndef ABSL_CRC_INTERNAL_CRC32C_H_ 16 #define ABSL_CRC_INTERNAL_CRC32C_H_ 17 18 #include "absl/base/config.h" 19 #include "absl/crc/crc32c.h" 20 21 namespace absl { 22 ABSL_NAMESPACE_BEGIN 23 namespace crc_internal { 24 25 // Modifies a CRC32 value by removing `length` bytes with a value of 0 from 26 // the end of the string. 27 // 28 // This is the inverse operation of ExtendCrc32cByZeroes(). 29 // 30 // This operation has a runtime cost of O(log(`length`)) 31 // 32 // Internal implementation detail, exposed for testing only. 33 crc32c_t UnextendCrc32cByZeroes(crc32c_t initial_crc, size_t length); 34 35 } // namespace crc_internal 36 ABSL_NAMESPACE_END 37 } // namespace absl 38 39 #endif // ABSL_CRC_INTERNAL_CRC32C_H_ 40