go/arrow/datatype.go

// 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.

package arrow

// Type is a logical type. They can be expressed as
// either a primitive physical type (bytes or bits of some fixed size), a
// nested type consisting of other data types, or another data type (e.g. a
// timestamp encoded as an int64)
type Type int

const (
	// NULL type having no physical storage
	NULL Type = iota

	// BOOL is a 1 bit, LSB bit-packed ordering
	BOOL

	// UINT8 is an Unsigned 8-bit little-endian integer
	UINT8

	// INT8 is a Signed 8-bit little-endian integer
	INT8

	// UINT16 is an Unsigned 16-bit little-endian integer
	UINT16

	// INT16 is a Signed 16-bit little-endian integer
	INT16

	// UINT32 is an Unsigned 32-bit little-endian integer
	UINT32

	// INT32 is a Signed 32-bit little-endian integer
	INT32

	// UINT64 is an Unsigned 64-bit little-endian integer
	UINT64

	// INT64 is a Signed 64-bit little-endian integer
	INT64

	// HALF_FLOAT is a 2-byte floating point value
	HALF_FLOAT

	// FLOAT32 is a 4-byte floating point value
	FLOAT32

	// FLOAT64 is an 8-byte floating point value
	FLOAT64

	// STRING is a UTF8 variable-length string
	STRING

	// BINARY is a Variable-length byte type (no guarantee of UTF8-ness)
	BINARY

	// FIXED_SIZE_BINARY is a binary where each value occupies the same number of bytes
	FIXED_SIZE_BINARY

	// DATE32 is int32 days since the UNIX epoch
	DATE32

	// DATE64 is int64 milliseconds since the UNIX epoch
	DATE64

	// TIMESTAMP is an exact timestamp encoded with int64 since UNIX epoch
	// Default unit millisecond
	TIMESTAMP

	// TIME32 is a signed 32-bit integer, representing either seconds or
	// milliseconds since midnight
	TIME32

	// TIME64 is a signed 64-bit integer, representing either microseconds or
	// nanoseconds since midnight
	TIME64

	// INTERVAL is YEAR_MONTH or DAY_TIME interval in SQL style
	INTERVAL

	// DECIMAL is a precision- and scale-based decimal type. Storage type depends on the
	// parameters.
	DECIMAL

	// LIST is a list of some logical data type
	LIST

	// STRUCT of logical types
	STRUCT

	// UNION of logical types
	UNION

	// DICTIONARY aka Category type
	DICTIONARY

	// MAP is a repeated struct logical type
	MAP
)

// DataType is the representation of an Arrow type.
type DataType interface {
	ID() Type
	// Name is name of the data type.
	Name() string
}

// FixedWidthDataType is the representation of an Arrow type that
// requires a fixed number of bits in memory for each element.
type FixedWidthDataType interface {
	DataType
	// BitWidth returns the number of bits required to store a single element of this data type in memory.
	BitWidth() int
}

type BinaryDataType interface {
	DataType
	binary()
}