bkietz commented on a change in pull request #9621: URL: https://github.com/apache/arrow/pull/9621#discussion_r599010908
########## File path: cpp/src/arrow/compute/kernels/hash_aggregate.cc ########## @@ -0,0 +1,1050 @@ +// 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 "arrow/compute/api_aggregate.h" + +#include <functional> +#include <memory> +#include <string> +#include <unordered_map> +#include <vector> + +#include "arrow/buffer_builder.h" +#include "arrow/compute/api_vector.h" +#include "arrow/compute/exec_internal.h" +#include "arrow/compute/kernel.h" +#include "arrow/compute/kernels/aggregate_internal.h" +#include "arrow/compute/kernels/common.h" +#include "arrow/util/bit_run_reader.h" +#include "arrow/util/bitmap_ops.h" +#include "arrow/util/checked_cast.h" +#include "arrow/util/make_unique.h" +#include "arrow/visitor_inline.h" + +namespace arrow { + +using internal::checked_cast; + +namespace compute { +namespace internal { +namespace { + +struct KeyEncoder { + // the first byte of an encoded key is used to indicate nullity + static constexpr bool kExtraByteForNull = true; + + virtual ~KeyEncoder() = default; + + virtual void AddLength(const ArrayData&, int32_t* lengths) = 0; + + virtual Status Encode(const ArrayData&, uint8_t** encoded_bytes) = 0; + + virtual Result<std::shared_ptr<ArrayData>> Decode(uint8_t** encoded_bytes, + int32_t length, MemoryPool*) = 0; + + // extract the null bitmap from the leading nullity bytes of encoded keys + static Status DecodeNulls(MemoryPool* pool, int32_t length, uint8_t** encoded_bytes, + std::shared_ptr<Buffer>* null_buf, int32_t* null_count) { + // first count nulls to determine if a null bitmap is necessary + *null_count = 0; + for (int32_t i = 0; i < length; ++i) { + *null_count += encoded_bytes[i][0]; + } + + if (*null_count > 0) { + ARROW_ASSIGN_OR_RAISE(*null_buf, AllocateBitmap(length, pool)); + + uint8_t* nulls = (*null_buf)->mutable_data(); + for (int32_t i = 0; i < length; ++i) { + BitUtil::SetBitTo(nulls, i, !encoded_bytes[i][0]); + encoded_bytes[i] += 1; + } + } else { + for (int32_t i = 0; i < length; ++i) { + encoded_bytes[i] += 1; + } + } + return Status ::OK(); + } +}; + +struct BooleanKeyEncoder : KeyEncoder { + static constexpr int kByteWidth = 1; + + void AddLength(const ArrayData& data, int32_t* lengths) override { + for (int64_t i = 0; i < data.length; ++i) { + lengths[i] += kByteWidth + kExtraByteForNull; + } + } + + Status Encode(const ArrayData& data, uint8_t** encoded_bytes) override { + VisitArrayDataInline<BooleanType>( + data, + [&](bool value) { + auto& encoded_ptr = *encoded_bytes++; + *encoded_ptr++ = 0; Review comment: alright -- 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: [email protected]
