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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.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using Apache.Arrow.Types;
namespace Apache.Arrow.Ipc
{
internal class MessageSerializer
{
public const int IpcContinuationToken = -1;
public static Types.NumberType GetNumberType(int bitWidth, bool signed)
{
if (signed)
{
if (bitWidth == 8)
return Types.Int8Type.Default;
if (bitWidth == 16)
return Types.Int16Type.Default;
if (bitWidth == 32)
return Types.Int32Type.Default;
if (bitWidth == 64)
return Types.Int64Type.Default;
}
else
{
if (bitWidth == 8)
return Types.UInt8Type.Default;
if (bitWidth == 16)
return Types.UInt16Type.Default;
if (bitWidth == 32)
return Types.UInt32Type.Default;
if (bitWidth == 64)
return Types.UInt64Type.Default;
}
throw new Exception($"Unexpected bit width of {bitWidth} for " +
$"{(signed ? "signed " : "unsigned")} integer.");
}
internal static Schema GetSchema(Flatbuf.Schema schema, ref DictionaryMemo dictionaryMemo)
{
List<Field> fields = new List<Field>();
for (int i = 0; i < schema.FieldsLength; i++)
{
Flatbuf.Field field = schema.Fields(i).GetValueOrDefault();
fields.Add(FieldFromFlatbuffer(field, ref dictionaryMemo));
}
Dictionary<string, string> metadata = schema.CustomMetadataLength > 0 ? new Dictionary<string, string>() : null;
for (int i = 0; i < schema.CustomMetadataLength; i++)
{
Flatbuf.KeyValue keyValue = schema.CustomMetadata(i).GetValueOrDefault();
metadata[keyValue.Key] = keyValue.Value;
}
return new Schema(fields, metadata, copyCollections: false);
}
private static Field FieldFromFlatbuffer(Flatbuf.Field flatbufField, ref DictionaryMemo dictionaryMemo)
{
Field[] childFields = flatbufField.ChildrenLength > 0 ? new Field[flatbufField.ChildrenLength] : null;
for (int i = 0; i < flatbufField.ChildrenLength; i++)
{
Flatbuf.Field? childFlatbufField = flatbufField.Children(i);
childFields[i] = FieldFromFlatbuffer(childFlatbufField.Value, ref dictionaryMemo);
}
Flatbuf.DictionaryEncoding? dictionaryEncoding = flatbufField.Dictionary;
IArrowType type = GetFieldArrowType(flatbufField, childFields);
if (dictionaryEncoding.HasValue)
{
Flatbuf.Int? indexTypeAsInt = dictionaryEncoding.Value.IndexType;
IArrowType indexType = indexTypeAsInt.HasValue ?
GetNumberType(indexTypeAsInt.Value.BitWidth, indexTypeAsInt.Value.IsSigned) :
GetNumberType(Int32Type.Default.BitWidth, Int32Type.Default.IsSigned);
type = new DictionaryType(indexType, type, dictionaryEncoding.Value.IsOrdered);
}
Dictionary<string, string> metadata = flatbufField.CustomMetadataLength > 0 ? new Dictionary<string, string>() : null;
for (int i = 0; i < flatbufField.CustomMetadataLength; i++)
{
Flatbuf.KeyValue keyValue = flatbufField.CustomMetadata(i).GetValueOrDefault();
metadata[keyValue.Key] = keyValue.Value;
}
var arrowField = new Field(flatbufField.Name, type, flatbufField.Nullable, metadata, copyCollections: false);
if (dictionaryEncoding.HasValue)
{
dictionaryMemo ??= new DictionaryMemo();
dictionaryMemo.AddField(dictionaryEncoding.Value.Id, arrowField);
}
return arrowField;
}
private static Types.IArrowType GetFieldArrowType(Flatbuf.Field field, Field[] childFields = null)
{
switch (field.TypeType)
{
case Flatbuf.Type.Int:
Flatbuf.Int intMetaData = field.Type<Flatbuf.Int>().Value;
return MessageSerializer.GetNumberType(intMetaData.BitWidth, intMetaData.IsSigned);
case Flatbuf.Type.FloatingPoint:
Flatbuf.FloatingPoint floatingPointTypeMetadata = field.Type<Flatbuf.FloatingPoint>().Value;
switch (floatingPointTypeMetadata.Precision)
{
case Flatbuf.Precision.SINGLE:
return Types.FloatType.Default;
case Flatbuf.Precision.DOUBLE:
return Types.DoubleType.Default;
case Flatbuf.Precision.HALF:
return Types.HalfFloatType.Default;
default:
throw new InvalidDataException("Unsupported floating point precision");
}
case Flatbuf.Type.Bool:
return new Types.BooleanType();
case Flatbuf.Type.Decimal:
Flatbuf.Decimal decMeta = field.Type<Flatbuf.Decimal>().Value;
switch (decMeta.BitWidth)
{
case 128:
return new Types.Decimal128Type(decMeta.Precision, decMeta.Scale);
case 256:
return new Types.Decimal256Type(decMeta.Precision, decMeta.Scale);
default:
throw new InvalidDataException("Unsupported decimal bit width " + decMeta.BitWidth);
}
case Flatbuf.Type.Date:
Flatbuf.Date dateMeta = field.Type<Flatbuf.Date>().Value;
switch (dateMeta.Unit)
{
case Flatbuf.DateUnit.DAY:
return Types.Date32Type.Default;
case Flatbuf.DateUnit.MILLISECOND:
return Types.Date64Type.Default;
default:
throw new InvalidDataException("Unsupported date unit");
}
case Flatbuf.Type.Time:
Flatbuf.Time timeMeta = field.Type<Flatbuf.Time>().Value;
switch (timeMeta.BitWidth)
{
case 32:
return new Types.Time32Type(timeMeta.Unit.ToArrow());
case 64:
return new Types.Time64Type(timeMeta.Unit.ToArrow());
default:
throw new InvalidDataException("Unsupported time bit width");
}
case Flatbuf.Type.Timestamp:
Flatbuf.Timestamp timestampTypeMetadata = field.Type<Flatbuf.Timestamp>().Value;
Types.TimeUnit unit = timestampTypeMetadata.Unit.ToArrow();
string timezone = timestampTypeMetadata.Timezone;
return new Types.TimestampType(unit, timezone);
case Flatbuf.Type.Interval:
Flatbuf.Interval intervalMetadata = field.Type<Flatbuf.Interval>().Value;
return new Types.IntervalType(intervalMetadata.Unit.ToArrow());
case Flatbuf.Type.Utf8:
return new Types.StringType();
case Flatbuf.Type.FixedSizeBinary:
Flatbuf.FixedSizeBinary fixedSizeBinaryMetadata = field.Type<Flatbuf.FixedSizeBinary>().Value;
return new Types.FixedSizeBinaryType(fixedSizeBinaryMetadata.ByteWidth);
case Flatbuf.Type.Binary:
return Types.BinaryType.Default;
case Flatbuf.Type.List:
if (childFields == null || childFields.Length != 1)
{
throw new InvalidDataException($"List type must have exactly one child.");
}
return new Types.ListType(childFields[0]);
case Flatbuf.Type.Struct_:
Debug.Assert(childFields != null);
return new Types.StructType(childFields);
default:
throw new InvalidDataException($"Arrow primitive '{field.TypeType}' is unsupported.");
}
}
}
}
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