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// 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.
/// DEPRECATED: Feather V2 is available starting in version 0.17.0 and does not
/// use this file at all.
namespace arrow.ipc.feather.fbs;
/// Feather is an experimental serialization format implemented using
/// techniques from Apache Arrow. It was created as a proof-of-concept of an
/// interoperable file format for storing data frames originating in Python or
/// R. It enabled the developers to sidestep some of the open design questions
/// in Arrow from early 2016 and instead create something simple and useful for
/// the intended use cases.
enum Type : byte {
BOOL = 0,
INT8 = 1,
INT16 = 2,
INT32 = 3,
INT64 = 4,
UINT8 = 5,
UINT16 = 6,
UINT32 = 7,
UINT64 = 8,
FLOAT = 9,
DOUBLE = 10,
UTF8 = 11,
BINARY = 12,
CATEGORY = 13,
TIMESTAMP = 14,
DATE = 15,
TIME = 16,
LARGE_UTF8 = 17,
LARGE_BINARY = 18
}
enum Encoding : byte {
PLAIN = 0,
/// Data is stored dictionary-encoded
/// dictionary size: <INT32 Dictionary size>
/// dictionary data: <TYPE primitive array>
/// dictionary index: <INT32 primitive array>
///
/// TODO: do we care about storing the index values in a smaller typeclass
DICTIONARY = 1
}
enum TimeUnit : byte {
SECOND = 0,
MILLISECOND = 1,
MICROSECOND = 2,
NANOSECOND = 3
}
table PrimitiveArray {
type: Type;
encoding: Encoding = PLAIN;
/// Relative memory offset of the start of the array data excluding the size
/// of the metadata
offset: long;
/// The number of logical values in the array
length: long;
/// The number of observed nulls
null_count: long;
/// The total size of the actual data in the file
total_bytes: long;
/// TODO: Compression
}
table CategoryMetadata {
/// The category codes are presumed to be integers that are valid indexes into
/// the levels array
levels: PrimitiveArray;
ordered: bool = false;
}
table TimestampMetadata {
unit: TimeUnit;
/// Timestamp data is assumed to be UTC, but the time zone is stored here for
/// presentation as localized
time_zone: string;
}
table DateMetadata {
}
table TimeMetadata {
unit: TimeUnit;
}
union TypeMetadata {
CategoryMetadata,
TimestampMetadata,
DateMetadata,
TimeMetadata,
}
table Column {
name: string;
values: PrimitiveArray;
metadata: TypeMetadata;
/// This should (probably) be JSON
user_metadata: string;
}
table CTable {
/// Some text (or a name) metadata about what the file is, optional
description: string;
num_rows: long;
columns: [Column];
/// Version number of the Feather format
///
/// Internal versions 0, 1, and 2: Implemented in Apache Arrow <= 0.16.0 and
/// wesm/feather. Uses "custom" metadata defined in this file.
version: int;
/// Table metadata (likely JSON), not yet used
metadata: string;
}
root_type CTable;
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