fgerlits commented on a change in pull request #791: URL: https://github.com/apache/nifi-minifi-cpp/pull/791#discussion_r435322591
########## File path: libminifi/src/utils/file/FileUtils.cpp ########## @@ -0,0 +1,58 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 + * + * http://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 "utils/file/FileUtils.h" + +#include <zlib.h> + +#include <algorithm> +#include <iostream> + +namespace org { +namespace apache { +namespace nifi { +namespace minifi { +namespace utils { +namespace file { + + uint64_t FileUtils::computeChecksum(std::string file_name, uint64_t up_to_position) { + constexpr uint64_t BUFFER_SIZE = 4096u; + std::array<char, (std::size_t) BUFFER_SIZE> buffer; + + std::ifstream stream{file_name, std::ios::in | std::ios::binary}; + + uint64_t checksum = 0; + uint64_t remaining_bytes_to_be_read = up_to_position; + + while (stream && remaining_bytes_to_be_read > 0) { + using std::min; // for min(), to work around https://docs.microsoft.com/en-us/windows/win32/multimedia/min + stream.read(buffer.data(), min(BUFFER_SIZE, remaining_bytes_to_be_read)); + uint64_t bytes_read = stream.gcount(); + checksum = crc32(checksum, reinterpret_cast<unsigned char*>(buffer.data()), bytes_read); + remaining_bytes_to_be_read -= bytes_read; + } + + return checksum; + } Review comment: fixed ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
