kun yu 77e1ddd81b branch-0.4.0
Former-commit-id: a4df63653202df32d0b983de27f5c969905d17ac
2019-07-30 10:23:34 +08:00

70 lines
2.4 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.
#ifndef ARROW_CSV_CHUNKER_H
#define ARROW_CSV_CHUNKER_H
#include <cstdint>
#include "arrow/csv/options.h"
#include "arrow/status.h"
#include "arrow/util/macros.h"
#include "arrow/util/visibility.h"
namespace arrow {
namespace csv {
/// \class Chunker
/// \brief A reusable block-based chunker for CSV data
///
/// The chunker takes a block of CSV data and finds a suitable place
/// to cut it up without splitting a row.
/// If the block is truncated (i.e. not all data can be chunked), it is up
/// to the caller to arrange the next block to start with the trailing data.
///
/// Note: if the previous block ends with CR (0x0d) and a new block starts
/// with LF (0x0a), the chunker will consider the leading newline as an empty line.
class ARROW_EXPORT Chunker {
public:
explicit Chunker(ParseOptions options);
/// \brief Carve up a chunk in a block of data
///
/// Process a block of CSV data, reading up to size bytes.
/// The number of bytes in the chunk is returned in out_size.
Status Process(const char* data, uint32_t size, uint32_t* out_size);
protected:
ARROW_DISALLOW_COPY_AND_ASSIGN(Chunker);
// Like Process(), but specialized for some parsing options
template <bool quoting, bool escaping>
Status ProcessSpecialized(const char* data, uint32_t size, uint32_t* out_size);
// Detect a single line from the data pointer. Return the line end,
// or nullptr if the remaining line is truncated.
template <bool quoting, bool escaping>
inline const char* ReadLine(const char* data, const char* data_end);
ParseOptions options_;
};
} // namespace csv
} // namespace arrow
#endif // ARROW_CSV_CHUNKER_H