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datatype_nested.go
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datatype_nested.go
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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.
package arrow
import (
"errors"
"fmt"
"strconv"
"strings"
"github.com/apache/arrow/go/v10/arrow/internal/debug"
)
type NestedType interface {
DataType
Fields() []Field
}
// ListType describes a nested type in which each array slot contains
// a variable-size sequence of values, all having the same relative type.
type ListType struct {
elem Field
}
func ListOfField(f Field) *ListType {
if f.Type == nil {
panic("arrow: nil type for list field")
}
return &ListType{elem: f}
}
// ListOf returns the list type with element type t.
// For example, if t represents int32, ListOf(t) represents []int32.
//
// ListOf panics if t is nil or invalid. NullableElem defaults to true
func ListOf(t DataType) *ListType {
if t == nil {
panic("arrow: nil DataType")
}
return &ListType{elem: Field{Name: "item", Type: t, Nullable: true}}
}
// ListOfNonNullable is like ListOf but NullableElem defaults to false, indicating
// that the child type should be marked as non-nullable.
func ListOfNonNullable(t DataType) *ListType {
if t == nil {
panic("arrow: nil DataType")
}
return &ListType{elem: Field{Name: "item", Type: t, Nullable: false}}
}
func (*ListType) ID() Type { return LIST }
func (*ListType) Name() string { return "list" }
func (t *ListType) String() string {
if t.elem.Nullable {
return fmt.Sprintf("list<%s: %s, nullable>", t.elem.Name, t.elem.Type)
}
return fmt.Sprintf("list<%s: %s>", t.elem.Name, t.elem.Type)
}
func (t *ListType) Fingerprint() string {
child := t.elem.Type.Fingerprint()
if len(child) > 0 {
return typeFingerprint(t) + "{" + child + "}"
}
return ""
}
func (t *ListType) SetElemMetadata(md Metadata) { t.elem.Metadata = md }
func (t *ListType) SetElemNullable(n bool) { t.elem.Nullable = n }
// Elem returns the ListType's element type.
func (t *ListType) Elem() DataType { return t.elem.Type }
func (t *ListType) ElemField() Field {
return t.elem
}
func (t *ListType) Fields() []Field { return []Field{t.ElemField()} }
func (ListType) Layout() DataTypeLayout {
return DataTypeLayout{Buffers: []BufferSpec{SpecBitmap(), SpecFixedWidth(Int32SizeBytes)}}
}
func (ListType) OffsetTypeTraits() OffsetTraits { return Int32Traits }
type LargeListType struct {
ListType
}
func (LargeListType) ID() Type { return LARGE_LIST }
func (LargeListType) Name() string { return "large_list" }
func (t *LargeListType) String() string {
return "large_" + t.ListType.String()
}
func (t *LargeListType) Fingerprint() string {
child := t.elem.Type.Fingerprint()
if len(child) > 0 {
return typeFingerprint(t) + "{" + child + "}"
}
return ""
}
func (LargeListType) Layout() DataTypeLayout {
return DataTypeLayout{Buffers: []BufferSpec{SpecBitmap(), SpecFixedWidth(Int64SizeBytes)}}
}
func (LargeListType) OffsetTypeTraits() OffsetTraits { return Int64Traits }
func LargeListOfField(f Field) *LargeListType {
if f.Type == nil {
panic("arrow: nil type for list field")
}
return &LargeListType{ListType{elem: f}}
}
// ListOf returns the list type with element type t.
// For example, if t represents int32, ListOf(t) represents []int32.
//
// ListOf panics if t is nil or invalid. NullableElem defaults to true
func LargeListOf(t DataType) *LargeListType {
if t == nil {
panic("arrow: nil DataType")
}
return &LargeListType{ListType{elem: Field{Name: "item", Type: t, Nullable: true}}}
}
// ListOfNonNullable is like ListOf but NullableElem defaults to false, indicating
// that the child type should be marked as non-nullable.
func LargeListOfNonNullable(t DataType) *LargeListType {
if t == nil {
panic("arrow: nil DataType")
}
return &LargeListType{ListType{elem: Field{Name: "item", Type: t, Nullable: false}}}
}
// FixedSizeListType describes a nested type in which each array slot contains
// a fixed-size sequence of values, all having the same relative type.
type FixedSizeListType struct {
n int32 // number of elements in the list
elem Field
}
func FixedSizeListOfField(n int32, f Field) *FixedSizeListType {
if f.Type == nil {
panic("arrow: nil DataType")
}
if n <= 0 {
panic("arrow: invalid size")
}
return &FixedSizeListType{n: n, elem: f}
}
// FixedSizeListOf returns the list type with element type t.
// For example, if t represents int32, FixedSizeListOf(10, t) represents [10]int32.
//
// FixedSizeListOf panics if t is nil or invalid.
// FixedSizeListOf panics if n is <= 0.
// NullableElem defaults to true
func FixedSizeListOf(n int32, t DataType) *FixedSizeListType {
if t == nil {
panic("arrow: nil DataType")
}
if n <= 0 {
panic("arrow: invalid size")
}
return &FixedSizeListType{n: n, elem: Field{Name: "item", Type: t, Nullable: true}}
}
// FixedSizeListOfNonNullable is like FixedSizeListOf but NullableElem defaults to false
// indicating that the child type should be marked as non-nullable.
func FixedSizeListOfNonNullable(n int32, t DataType) *FixedSizeListType {
if t == nil {
panic("arrow: nil DataType")
}
if n <= 0 {
panic("arrow: invalid size")
}
return &FixedSizeListType{n: n, elem: Field{Name: "item", Type: t, Nullable: false}}
}
func (*FixedSizeListType) ID() Type { return FIXED_SIZE_LIST }
func (*FixedSizeListType) Name() string { return "fixed_size_list" }
func (t *FixedSizeListType) String() string {
if t.elem.Nullable {
return fmt.Sprintf("fixed_size_list<%s: %s, nullable>[%d]", t.elem.Name, t.elem.Type, t.n)
}
return fmt.Sprintf("fixed_size_list<%s: %s>[%d]", t.elem.Name, t.elem.Type, t.n)
}
// Elem returns the FixedSizeListType's element type.
func (t *FixedSizeListType) Elem() DataType { return t.elem.Type }
// Len returns the FixedSizeListType's size.
func (t *FixedSizeListType) Len() int32 { return t.n }
func (t *FixedSizeListType) ElemField() Field {
return t.elem
}
func (t *FixedSizeListType) Fingerprint() string {
child := t.elem.Type.Fingerprint()
if len(child) > 0 {
return fmt.Sprintf("%s[%d]{%s}", typeFingerprint(t), t.n, child)
}
return ""
}
func (t *FixedSizeListType) Fields() []Field { return []Field{t.ElemField()} }
func (FixedSizeListType) Layout() DataTypeLayout {
return DataTypeLayout{Buffers: []BufferSpec{SpecBitmap()}}
}
// StructType describes a nested type parameterized by an ordered sequence
// of relative types, called its fields.
type StructType struct {
fields []Field
index map[string]int
meta Metadata
}
// StructOf returns the struct type with fields fs.
//
// StructOf panics if there are duplicated fields.
// StructOf panics if there is a field with an invalid DataType.
func StructOf(fs ...Field) *StructType {
n := len(fs)
if n == 0 {
return &StructType{}
}
t := &StructType{
fields: make([]Field, n),
index: make(map[string]int, n),
}
for i, f := range fs {
if f.Type == nil {
panic("arrow: field with nil DataType")
}
t.fields[i] = Field{
Name: f.Name,
Type: f.Type,
Nullable: f.Nullable,
Metadata: f.Metadata.clone(),
}
if _, dup := t.index[f.Name]; dup {
panic(fmt.Errorf("arrow: duplicate field with name %q", f.Name))
}
t.index[f.Name] = i
}
return t
}
func (*StructType) ID() Type { return STRUCT }
func (*StructType) Name() string { return "struct" }
func (t *StructType) String() string {
var o strings.Builder
o.WriteString("struct<")
for i, f := range t.fields {
if i > 0 {
o.WriteString(", ")
}
o.WriteString(fmt.Sprintf("%s: %v", f.Name, f.Type))
}
o.WriteString(">")
return o.String()
}
func (t *StructType) Fields() []Field { return t.fields }
func (t *StructType) Field(i int) Field { return t.fields[i] }
func (t *StructType) FieldByName(name string) (Field, bool) {
i, ok := t.index[name]
if !ok {
return Field{}, false
}
return t.fields[i], true
}
func (t *StructType) FieldIdx(name string) (int, bool) {
i, ok := t.index[name]
return i, ok
}
func (t *StructType) Fingerprint() string {
var b strings.Builder
b.WriteString(typeFingerprint(t))
b.WriteByte('{')
for _, c := range t.fields {
child := c.Fingerprint()
if len(child) == 0 {
return ""
}
b.WriteString(child)
b.WriteByte(';')
}
b.WriteByte('}')
return b.String()
}
func (StructType) Layout() DataTypeLayout {
return DataTypeLayout{Buffers: []BufferSpec{SpecBitmap()}}
}
type MapType struct {
value *ListType
KeysSorted bool
}
func MapOf(key, item DataType) *MapType {
if key == nil || item == nil {
panic("arrow: nil key or item type for MapType")
}
return &MapType{value: ListOf(StructOf(Field{Name: "key", Type: key}, Field{Name: "value", Type: item, Nullable: true}))}
}
func (*MapType) ID() Type { return MAP }
func (*MapType) Name() string { return "map" }
func (t *MapType) String() string {
var o strings.Builder
o.WriteString(fmt.Sprintf("map<%s, %s",
t.value.Elem().(*StructType).Field(0).Type,
t.value.Elem().(*StructType).Field(1).Type))
if t.KeysSorted {
o.WriteString(", keys_sorted")
}
o.WriteString(">")
return o.String()
}
func (t *MapType) KeyField() Field { return t.value.Elem().(*StructType).Field(0) }
func (t *MapType) KeyType() DataType { return t.KeyField().Type }
func (t *MapType) ItemField() Field { return t.value.Elem().(*StructType).Field(1) }
func (t *MapType) ItemType() DataType { return t.ItemField().Type }
func (t *MapType) ValueType() *StructType { return t.value.Elem().(*StructType) }
func (t *MapType) ValueField() Field {
return Field{
Name: "entries",
Type: t.ValueType(),
}
}
func (t *MapType) SetItemNullable(nullable bool) {
t.value.Elem().(*StructType).fields[1].Nullable = nullable
}
func (t *MapType) Fingerprint() string {
keyFingerprint := t.KeyType().Fingerprint()
itemFingerprint := t.ItemType().Fingerprint()
if keyFingerprint == "" || itemFingerprint == "" {
return ""
}
fingerprint := typeFingerprint(t)
if t.KeysSorted {
fingerprint += "s"
}
return fingerprint + "{" + keyFingerprint + itemFingerprint + "}"
}
func (t *MapType) Fields() []Field { return []Field{t.ValueField()} }
func (t *MapType) Layout() DataTypeLayout {
return t.value.Layout()
}
func (MapType) OffsetTypeTraits() OffsetTraits { return Int32Traits }
type (
// UnionTypeCode is an alias to int8 which is the type of the ids
// used for union arrays.
UnionTypeCode = int8
UnionMode int8
)
const (
MaxUnionTypeCode UnionTypeCode = 127
InvalidUnionChildID int = -1
SparseMode UnionMode = iota // SPARSE
DenseMode // DENSE
)
// UnionType is an interface to encompass both Dense and Sparse Union types.
//
// A UnionType is a nested type where each logical value is taken
// from a single child. A buffer of 8-bit type ids (typed as UnionTypeCode)
// indicates which child a given logical value is to be taken from. This is
// represented as the "child id" or "child index", which is the index into the
// list of child fields for a given child.
type UnionType interface {
NestedType
// Mode returns either SparseMode or DenseMode depending on the current
// concrete data type.
Mode() UnionMode
// ChildIDs returns a slice of ints to map UnionTypeCode values to
// the index in the Fields that represents the given Type. It is
// initialized with all values being InvalidUnionChildID (-1)
// before being populated based on the TypeCodes and fields of the type.
// The field for a given type can be retrieved by Fields()[ChildIDs()[typeCode]]
ChildIDs() []int
// TypeCodes returns the list of available type codes for this union type
// which will correspond to indexes into the ChildIDs slice to locate the
// appropriate child. A union Array contains a buffer of these type codes
// which indicate for a given index, which child has the value for that index.
TypeCodes() []UnionTypeCode
// MaxTypeCode returns the value of the largest TypeCode in the list of typecodes
// that are defined by this Union type
MaxTypeCode() UnionTypeCode
}
// UnionOf returns an appropriate union type for the given Mode (Sparse or Dense),
// child fields, and type codes. len(fields) == len(typeCodes) must be true, or else
// this will panic. len(fields) can be 0.
func UnionOf(mode UnionMode, fields []Field, typeCodes []UnionTypeCode) UnionType {
switch mode {
case SparseMode:
return SparseUnionOf(fields, typeCodes)
case DenseMode:
return DenseUnionOf(fields, typeCodes)
default:
panic("arrow: invalid union mode")
}
}
type unionType struct {
children []Field
typeCodes []UnionTypeCode
childIDs [int(MaxUnionTypeCode) + 1]int
}
func (t *unionType) init(fields []Field, typeCodes []UnionTypeCode) {
// initialize all child IDs to -1
t.childIDs[0] = InvalidUnionChildID
for i := 1; i < len(t.childIDs); i *= 2 {
copy(t.childIDs[i:], t.childIDs[:i])
}
t.children = fields
t.typeCodes = typeCodes
for i, tc := range t.typeCodes {
t.childIDs[tc] = i
}
}
func (t unionType) Fields() []Field { return t.children }
func (t unionType) TypeCodes() []UnionTypeCode { return t.typeCodes }
func (t unionType) ChildIDs() []int { return t.childIDs[:] }
func (t *unionType) validate(fields []Field, typeCodes []UnionTypeCode, _ UnionMode) error {
if len(fields) != len(typeCodes) {
return errors.New("arrow: union types should have the same number of fields as type codes")
}
for _, c := range typeCodes {
if c < 0 || c > MaxUnionTypeCode {
return errors.New("arrow: union type code out of bounds")
}
}
return nil
}
func (t *unionType) MaxTypeCode() (max UnionTypeCode) {
if len(t.typeCodes) == 0 {
return
}
max = t.typeCodes[0]
for _, c := range t.typeCodes[1:] {
if c > max {
max = c
}
}
return
}
func (t *unionType) String() string {
var b strings.Builder
b.WriteByte('<')
for i := range t.typeCodes {
if i != 0 {
b.WriteString(", ")
}
fmt.Fprintf(&b, "%s=%d", t.children[i], t.typeCodes[i])
}
b.WriteByte('>')
return b.String()
}
func (t *unionType) fingerprint() string {
var b strings.Builder
for _, c := range t.typeCodes {
fmt.Fprintf(&b, ":%d", c)
}
b.WriteString("]{")
for _, c := range t.children {
fingerprint := c.Fingerprint()
if len(fingerprint) == 0 {
return ""
}
b.WriteString(fingerprint)
b.WriteByte(';')
}
b.WriteByte('}')
return b.String()
}
func fieldsFromArrays(arrays []Array, names ...string) (ret []Field) {
ret = make([]Field, len(arrays))
if len(names) == 0 {
for i, c := range arrays {
ret[i] = Field{Name: strconv.Itoa(i), Type: c.DataType(), Nullable: true}
}
} else {
debug.Assert(len(names) == len(arrays), "mismatch of arrays and names")
for i, c := range arrays {
ret[i] = Field{Name: names[i], Type: c.DataType(), Nullable: true}
}
}
return
}
// SparseUnionType is the concrete type for Sparse union data.
//
// A sparse union is a nested type where each logical value is taken
// from a single child. A buffer of 8-bit type ids indicates which child
// a given logical value is to be taken from.
//
// In a sparse union, each child array will have the same length as the
// union array itself, regardless of the actual number of union values which
// refer to it.
//
// Unlike most other types, unions do not have a top-level validity bitmap.
type SparseUnionType struct {
unionType
}
// SparseUnionFromArrays enables creating a union type from a list of Arrays,
// field names, and type codes. len(fields) should be either 0 or equal to len(children).
// len(codes) should also be either 0, or equal to len(children).
//
// If len(fields) == 0, then the fields will be named numerically as "0", "1", "2"...
// and so on. If len(codes) == 0, then the type codes will be constructed as
// [0, 1, 2, ..., n].
func SparseUnionFromArrays(children []Array, fields []string, codes []UnionTypeCode) *SparseUnionType {
if len(codes) == 0 {
codes = make([]UnionTypeCode, len(children))
for i := range children {
codes[i] = UnionTypeCode(i)
}
}
return SparseUnionOf(fieldsFromArrays(children, fields...), codes)
}
// SparseUnionOf is equivalent to UnionOf(arrow.SparseMode, fields, typeCodes),
// constructing a SparseUnionType from a list of fields and type codes.
//
// If len(fields) != len(typeCodes) this will panic. They are allowed to be
// of length 0.
func SparseUnionOf(fields []Field, typeCodes []UnionTypeCode) *SparseUnionType {
ret := &SparseUnionType{}
if err := ret.validate(fields, typeCodes, ret.Mode()); err != nil {
panic(err)
}
ret.init(fields, typeCodes)
return ret
}
func (SparseUnionType) ID() Type { return SPARSE_UNION }
func (SparseUnionType) Name() string { return "sparse_union" }
func (SparseUnionType) Mode() UnionMode { return SparseMode }
func (t *SparseUnionType) Fingerprint() string {
return typeFingerprint(t) + "[s" + t.fingerprint()
}
func (SparseUnionType) Layout() DataTypeLayout {
return DataTypeLayout{Buffers: []BufferSpec{SpecAlwaysNull(), SpecFixedWidth(Uint8SizeBytes)}}
}
func (t *SparseUnionType) String() string {
return t.Name() + t.unionType.String()
}
// DenseUnionType is the concrete type for dense union data.
//
// A dense union is a nested type where each logical value is taken from a
// single child, at a specific offset. A buffer of 8-bit type ids (typed
// as UnionTypeCode) indicates which child a given logical value is to be
// taken from and a buffer of 32-bit offsets indicating which physical position
// in the given child array has the logical value for that index.
//
// Unlike a sparse union, a dense union allows encoding only the child values
// which are actually referred to by the union array. This is counterbalanced
// by the additional footprint of the offsets buffer, and the additional
// indirection cost when looking up values.
//
// Unlike most other types, unions don't have a top-level validity bitmap
type DenseUnionType struct {
unionType
}
// DenseUnionFromArrays enables creating a union type from a list of Arrays,
// field names, and type codes. len(fields) should be either 0 or equal to len(children).
// len(codes) should also be either 0, or equal to len(children).
//
// If len(fields) == 0, then the fields will be named numerically as "0", "1", "2"...
// and so on. If len(codes) == 0, then the type codes will be constructed as
// [0, 1, 2, ..., n].
func DenseUnionFromArrays(children []Array, fields []string, codes []UnionTypeCode) *DenseUnionType {
if len(codes) == 0 {
codes = make([]UnionTypeCode, len(children))
for i := range children {
codes[i] = UnionTypeCode(i)
}
}
return DenseUnionOf(fieldsFromArrays(children, fields...), codes)
}
// DenseUnionOf is equivalent to UnionOf(arrow.DenseMode, fields, typeCodes),
// constructing a SparseUnionType from a list of fields and type codes.
//
// If len(fields) != len(typeCodes) this will panic. They are allowed to be
// of length 0.
func DenseUnionOf(fields []Field, typeCodes []UnionTypeCode) *DenseUnionType {
ret := &DenseUnionType{}
if err := ret.validate(fields, typeCodes, ret.Mode()); err != nil {
panic(err)
}
ret.init(fields, typeCodes)
return ret
}
func (DenseUnionType) ID() Type { return DENSE_UNION }
func (DenseUnionType) Name() string { return "dense_union" }
func (DenseUnionType) Mode() UnionMode { return DenseMode }
func (t *DenseUnionType) Fingerprint() string {
return typeFingerprint(t) + "[s" + t.fingerprint()
}
func (DenseUnionType) Layout() DataTypeLayout {
return DataTypeLayout{Buffers: []BufferSpec{SpecAlwaysNull(), SpecFixedWidth(Uint8SizeBytes), SpecFixedWidth(Int32SizeBytes)}}
}
func (DenseUnionType) OffsetTypeTraits() OffsetTraits { return Int32Traits }
func (t *DenseUnionType) String() string {
return t.Name() + t.unionType.String()
}
type Field struct {
Name string // Field name
Type DataType // The field's data type
Nullable bool // Fields can be nullable
Metadata Metadata // The field's metadata, if any
}
func (f Field) Fingerprint() string {
typeFingerprint := f.Type.Fingerprint()
if typeFingerprint == "" {
return ""
}
var b strings.Builder
b.WriteByte('F')
if f.Nullable {
b.WriteByte('n')
} else {
b.WriteByte('N')
}
b.WriteString(f.Name)
b.WriteByte('{')
b.WriteString(typeFingerprint)
b.WriteByte('}')
return b.String()
}
func (f Field) HasMetadata() bool { return f.Metadata.Len() != 0 }
func (f Field) Equal(o Field) bool {
switch {
case f.Name != o.Name:
return false
case f.Nullable != o.Nullable:
return false
case !TypeEqual(f.Type, o.Type, CheckMetadata()):
return false
case !f.Metadata.Equal(o.Metadata):
return false
}
return true
}
func (f Field) String() string {
var o strings.Builder
nullable := ""
if f.Nullable {
nullable = ", nullable"
}
fmt.Fprintf(&o, "%s: type=%v%v", f.Name, f.Type, nullable)
if f.HasMetadata() {
fmt.Fprintf(&o, "\n%*.smetadata: %v", len(f.Name)+2, "", f.Metadata)
}
return o.String()
}
var (
_ DataType = (*ListType)(nil)
_ DataType = (*FixedSizeListType)(nil)
_ DataType = (*StructType)(nil)
_ DataType = (*MapType)(nil)
)