pitrou commented on code in PR #35628: URL: https://github.com/apache/arrow/pull/35628#discussion_r1234256644
########## cpp/src/arrow/util/string_header.h: ########## @@ -0,0 +1,377 @@ +// 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. + +/* + * Copyright (c) Facebook, Inc. and its affiliates. + * + * Licensed 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. + */ + +#pragma once + +#include <array> +#include <cassert> +#include <cstdint> +#include <cstring> +#include <iosfwd> +#include <string> +#include <string_view> + +namespace arrow { + +/// Variable length string or binary with 4 byte prefix and inline optimization +/// for small values (12 bytes or fewer). This is similar to std::string_view +/// except that the referenced is limited in size to UINT32_MAX and up to the +/// first four bytes of the string are copied into the struct. The prefix allows +/// failing comparisons early and can reduce the CPU cache working set when +/// dealing with short strings. +/// +/// This structure supports three states: +/// +/// Short string |----|----|--------| +/// ^ ^ ^ +/// | | | +/// size prefix remaining in-line portion, zero padded +/// +/// Long string |----|----|--------| +/// ^ ^ ^ +/// | | | +/// size prefix raw pointer to out-of-line portion Review Comment: Can raw pointers be a separate PR? -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
