2022-05-23 00:16:32 +04:00

65 lines
2.3 KiB
C++

// 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.
#pragma once
#include <cstdint>
#include <memory>
#include <utility>
#include "arrow/result.h"
#include "arrow/type_fwd.h"
#include "arrow/util/type_fwd.h"
#include "arrow/util/visibility.h"
namespace arrow {
namespace csv {
class BlockParser;
struct ConvertOptions;
class ARROW_EXPORT ColumnDecoder {
public:
virtual ~ColumnDecoder() = default;
/// Spawn a task that will try to convert and insert the given CSV block
virtual Future<std::shared_ptr<Array>> Decode(
const std::shared_ptr<BlockParser>& parser) = 0;
/// Construct a strictly-typed ColumnDecoder.
static Result<std::shared_ptr<ColumnDecoder>> Make(MemoryPool* pool,
std::shared_ptr<DataType> type,
int32_t col_index,
const ConvertOptions& options);
/// Construct a type-inferring ColumnDecoder.
/// Inference will run only on the first block, the type will be frozen afterwards.
static Result<std::shared_ptr<ColumnDecoder>> Make(MemoryPool* pool, int32_t col_index,
const ConvertOptions& options);
/// Construct a ColumnDecoder for a column of nulls
/// (i.e. not present in the CSV file).
static Result<std::shared_ptr<ColumnDecoder>> MakeNull(MemoryPool* pool,
std::shared_ptr<DataType> type);
protected:
ColumnDecoder() = default;
};
} // namespace csv
} // namespace arrow