Package convex.core.data

Class VectorTree<T extends ACell>

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.data.ACountable<T>

convex.core.data.ADataStructure<T>

convex.core.data.ACollection<T>

convex.core.data.ASequence<T>

convex.core.data.AVector<T>

convex.core.data.VectorTree<T>

Type Parameters:

T - Type of Vector elements

All Implemented Interfaces:

IAssociative<CVMLong,T>, IValidated, IWriteable, Iterable<T>, Collection<T>, List<T>, SequencedCollection<T>

public class VectorTree<T extends ACell>
extends AVector<T>

Persistent Vector implemented as a merkle tree of chunks shift indicates the level of the tree: 4 = 1st level, 8 = second etc. Invariants:

• All children except the last must be fully packed
• Each non-terminal leaf chunk must be a tailless VectorLeaf of size 16

This implies that the entire tree must be a multiple of 16 in size. This is a desirable property as we want dense trees in our canonical representation. Any extra elements must be stored in a ListVector. This structure facilitates fast ~O(log(n)) operations for lookup and vector element update, and usually O(1) element additions/lookup at end. "Software gets slower faster than hardware gets faster" - Niklaus Wirth

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MAX_EMBEDDED_LENGTH
static final int	MAX_ENCODING_LENGTH
static final int	MINIMUM_SIZE

Fields inherited from class convex.core.data.ADataStructure

count

Fields inherited from class convex.core.data.ACell

cachedRef, memorySize

Fields inherited from class convex.core.data.AObject

encoding

Method Summary

Modifier and Type	Method	Description
boolean	allMatch(Predicate<? super T> pred)
boolean	anyMatch(Predicate<? super T> pred)
AVector<T>	append(T value)	Appends a single element to this vector
VectorTree<T>	appendChunk(AVector<T> b)	Appends a ListVector chunk to this vector.
AVector<T>	assoc(long i, T value)	Updates a value at the given position in the sequence.
long	commonPrefixLength(AVector<T> b)	Computes the length of the longest common prefix of this vector and another vector.
static int	computeShift(long count)	Computes the shift value for a BlockVector of the given count Note: if returns zero, count cannot be supported by a valid BlockVector
AVector<T>	concat(ASequence<? extends T> b)	Concatenates the elements from another sequence to the end of this sequence.
protected <K> void	copyToArray(K[] arr, int offset)	Copies the elements of this collection in order to an array at the specified offset
static <T extends ACell> VectorTree<T>	create(ACell[] things, int offset, int length)	Create a TreeVector with the specified elements - things must have at least 32 elements (the minimum TreeVector size) - must be a whole multiple of 16 elements (complete chunks only)
int	encode(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, including a tag byte which will be written first.
int	encodeRaw(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, excluding the tag byte.
boolean	equals(AVector<? super T> o)
int	estimatedEncodingSize()	Estimate the encoded data size for this Cell.
void	forEach(Consumer<? super T> action)
T	get(long i)	Gets the element at the specified index in this vector
VectorLeaf<T>	getChunk(long offset)	Gets the VectorLeaf chunk at a given offset
Ref<T>	getElementRef(long i)	Gets the element Ref at the specified index
protected Ref<T>	getElementRefUnsafe(long i)	Gets an element Ref from this vector, assuming bounds already checked
int	getEncodingLength()	Method to calculate the encoding length of a Cell.
<R extends ACell> Ref<R>	getRef(int i)	Gets a numbered child Ref from within this Cell.
int	getRefCount()	Gets the number of Refs contained within this Cell.
boolean	isCanonical()	Returns true if this vector is in canonical format, i.e.
boolean	isFullyPacked()	Returns true if this Vector is a single fully packed tree.
ListIterator<T>	listIterator()
ListIterator<T>	listIterator(long index)	Gets the ListIterator for a long position
long	longIndexOf(Object o)	Gets the first long index at which the specified value appears in the the sequence.
long	longLastIndexOf(Object o)	Gets the last long index at which the specified value appears in the the sequence.
<R extends ACell> AVector<R>	map(Function<? super T,? extends R> mapper)	Maps a function over a collection, applying it to each element in turn.
AVector<T>	next()	Gets the sequence of all elements after the first, or null if no elements remain after the first (i.e.
static <T extends ACell> VectorTree<T>	read(long count, Blob b, int pos)	Reads a VectorTree from the provided Blob Assumes the header byte and count is already checked.
<R> R	reduce(BiFunction<? super R,? super T,? extends R> func, R value)
AVector<T>	slice(long start, long end)	Produces a slice of this sequence, beginning with the specified start index and of the given length.
ACell	toCanonical()	Converts this Cell to a canonical version.
final AVector<T>	toVector()	Converts this collection to a canonical vector of elements
VectorTree<T>	updateRefs(IRefFunction func)	Updates all Refs in this object using the given function.
void	validate()	Validates the complete structure of this object.
void	validateCell()	Validates the local structure and invariants of this cell.
void	visitElementRefs(Consumer<Ref<T>> f)	Visits all elements in this sequence, calling the specified consumer for each.

Methods inherited from class convex.core.data.AVector

appendAll, conj, conjAll, cons, empty, equals, flatMap, get, getTag, getType, indexOf, isPacked, iterator, lastIndexOf, listIterator, mergeWith, print, reverse, subVector, toArray

Methods inherited from class convex.core.data.ASequence

add, addAll, assoc, checkRange, contains, containsKey, get, get, isCVMValue, remove, set, spliterator, spliterator, subList, toCellArray

Methods inherited from class convex.core.data.ACollection

add, addAll, clear, containsAll, remove, removeAll, retainAll, toArray

Methods inherited from class convex.core.data.ADataStructure

checkIndex, count, isDataValue, isEmpty, size, toCVMString

Methods inherited from class convex.core.data.ACountable

slice

Methods inherited from class convex.core.data.ACell

attachMemorySize, attachRef, cachedEncoding, cachedHash, calcMemorySize, createEncoding, createRef, equals, genericEquals, getCanonical, getChildRefs, getEncoding, getHash, getMemorySize, getMemorySize, getRef, hashCode, isEmbedded, toString

Methods inherited from class convex.core.data.AObject

attachEncoding, print, print

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.util.List

add, addAll, addFirst, addLast, clear, containsAll, equals, getFirst, getLast, hashCode, isEmpty, remove, removeAll, removeFirst, removeLast, replaceAll, retainAll, reversed, size, sort, toArray

Field Details

MINIMUM_SIZE

public static final int MINIMUM_SIZE

See Also:

• Constant Field Values

MAX_EMBEDDED_LENGTH

public static final int MAX_EMBEDDED_LENGTH

See Also:

• Constant Field Values

MAX_ENCODING_LENGTH

public static final int MAX_ENCODING_LENGTH

Method Details

computeShift

public static int computeShift(long count)

Computes the shift value for a BlockVector of the given count Note: if returns zero, count cannot be supported by a valid BlockVector

Parameters:

count - Number of elements

Returns:

Shift value

create

public static <T extends ACell> VectorTree<T> create(ACell[] things,
 int offset,
 int length)

Create a TreeVector with the specified elements - things must have at least 32 elements (the minimum TreeVector size) - must be a whole multiple of 16 elements (complete chunks only)

Parameters:

things - Elements to include

offset - Offset into element array

length - Number of elements to include

Returns:

New TreeVector instance

get

public T get(long i)

Description copied from class: AVector

Gets the element at the specified index in this vector

Specified by:

get in class AVector<T extends ACell>

Parameters:

i - The index of the element to get

Returns:

The element value at the specified index

getElementRef

public Ref<T> getElementRef(long i)

Description copied from class: ASequence

Gets the element Ref at the specified index

Specified by:

getElementRef in class ASequence<T extends ACell>

Parameters:

i - Index of element to get

Returns:

Ref to element at specified index

getElementRefUnsafe

protected Ref<T> getElementRefUnsafe(long i)

Description copied from class: AVector

Gets an element Ref from this vector, assuming bounds already checked

Specified by:

getElementRefUnsafe in class AVector<T extends ACell>

Parameters:

i - Index at which to get element Ref

Returns:

Element Ref

assoc

public AVector<T> assoc(long i,
 T value)

Description copied from class: ASequence

Updates a value at the given position in the sequence.

Specified by:

assoc in class AVector<T extends ACell>

Parameters:

i - Index of element to update

value - New element value

Returns:

Updated sequence, or null if index is out of range

encode

public int encode(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, including a tag byte which will be written first. Cell must be canonical, or else an error may occur.

Specified by:

encode in interface IWriteable

Specified by:

encode in class ACollection<T extends ACell>

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

encodeRaw

public int encodeRaw(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, excluding the tag byte.

Specified by:

encodeRaw in class AVector<T extends ACell>

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

getEncodingLength

public int getEncodingLength()

Description copied from class: ACell

Method to calculate the encoding length of a Cell. May be overridden to avoid creating encodings during memory size calculations. This reduces hashing!

Overrides:

getEncodingLength in class ACell

Returns:

Exact encoding length of this Cell

estimatedEncodingSize

public int estimatedEncodingSize()

Description copied from interface: IWriteable

Estimate the encoded data size for this Cell. Used for quickly sizing buffers. Implementations should try to return a size that is highly likely to contain the entire object when encoded, including the tag byte. Should not traverse soft Refs, i.e. must be usable on arbitrary partial data structures

Returns:

The estimated size for the binary representation of this object.

read

public static <T extends ACell> VectorTree<T> read(long count,
 Blob b,
 int pos)
                                            throws BadFormatException

Reads a VectorTree from the provided Blob Assumes the header byte and count is already checked.

Parameters:

count - Number of elements, assumed to be valid

b - Blob to read from

pos - Start position in Blob (location of tag byte)

Returns:

New decoded instance

Throws:

BadFormatException - In the event of any encoding error

appendChunk

public VectorTree<T> appendChunk(AVector<T> b)

Description copied from class: AVector

Appends a ListVector chunk to this vector. This vector must contain a whole number of chunks

Specified by:

appendChunk in class AVector<T extends ACell>

Parameters:

b - A chunk to append. Must be a ListVector of maximum size

Returns:

The updated vector, of the same type as this vector @

isFullyPacked

public boolean isFullyPacked()

Description copied from class: AVector

Returns true if this Vector is a single fully packed tree. i.e. a full ListVector or TreeVector.

Specified by:

isFullyPacked in class AVector<T extends ACell>

Returns:

true if fully packed, false otherwise

append

public AVector<T> append(T value)

Description copied from class: AVector

Appends a single element to this vector

Specified by:

append in class AVector<T extends ACell>

Parameters:

value - Value to append

Returns:

Updated vector

concat

public AVector<T> concat(ASequence<? extends T> b)

Description copied from class: ASequence

Concatenates the elements from another sequence to the end of this sequence. Potentially O(n) in size of resulting sequence

Specified by:

concat in class AVector<T extends ACell>

Parameters:

b - A sequence of values to concatenate.

Returns:

The concatenated sequence, of the same type as this sequence.

copyToArray

protected <K> void copyToArray(K[] arr,
 int offset)

Description copied from class: ACollection

Copies the elements of this collection in order to an array at the specified offset

Specified by:

copyToArray in class ACollection<T extends ACell>

Type Parameters:

K - Type of array elements required

Parameters:

arr -

offset -

longIndexOf

public long longIndexOf(Object o)

Description copied from class: ASequence

Gets the first long index at which the specified value appears in the the sequence. Similar to Java's standard List.indexOf(...) but supports long indexes.

Specified by:

longIndexOf in class ASequence<T extends ACell>

Parameters:

o - Any value which could appear as an element of the sequence.

Returns:

Index of the value, or -1 if not found.

longLastIndexOf

public long longLastIndexOf(Object o)

Description copied from class: ASequence

Gets the last long index at which the specified value appears in the the sequence. Similar to Java's standard List.lastIndexOf(...) but supports long indexes.

Specified by:

longLastIndexOf in class ASequence<T extends ACell>

Parameters:

o - Any value which could appear as an element of the sequence.

Returns:

Index of the value, or -1 if not found.

listIterator

public ListIterator<T> listIterator()

listIterator

public ListIterator<T> listIterator(long index)

Description copied from class: ASequence

Gets the ListIterator for a long position

Specified by:

listIterator in class AVector<T extends ACell>

Parameters:

index -

Returns:

ListIterator instance.

forEach

public void forEach(Consumer<? super T> action)

Specified by:

forEach in interface Iterable<T extends ACell>

Specified by:

forEach in class ASequence<T extends ACell>

anyMatch

public boolean anyMatch(Predicate<? super T> pred)

Specified by:

anyMatch in class AVector<T extends ACell>

allMatch

public boolean allMatch(Predicate<? super T> pred)

Specified by:

allMatch in class AVector<T extends ACell>

map

public <R extends ACell> AVector<R> map(Function<? super T,? extends R> mapper)

Description copied from class: ACollection

Maps a function over a collection, applying it to each element in turn.

Specified by:

map in class AVector<T extends ACell>

Type Parameters:

R - Type of element in resulting collection

Parameters:

mapper - Function to map over collection

Returns:

Collection after function applied to each element

visitElementRefs

public void visitElementRefs(Consumer<Ref<T>> f)

Description copied from class: ASequence

Visits all elements in this sequence, calling the specified consumer for each.

Specified by:

visitElementRefs in class ASequence<T extends ACell>

Parameters:

f - Function to call for each element

reduce

public <R> R reduce(BiFunction<? super R,? super T,? extends R> func,
 R value)

Specified by:

reduce in class AVector<T extends ACell>

isCanonical

public boolean isCanonical()

Description copied from class: AVector

Returns true if this vector is in canonical format, i.e. suitable as top-level serialised representation of a vector.

Specified by:

isCanonical in class AVector<T extends ACell>

Returns:

true if the vector is in canonical format, false otherwise

toCanonical

public ACell toCanonical()

Description copied from class: ACell

Converts this Cell to a canonical version. Must return this Cell if already canonical, may be O(n) in size of value otherwise. Callers should usually use getCanonical(), which caches canonical instances once created

Specified by:

toCanonical in class ACell

Returns:

Canonical version of Cell

toVector

public final AVector<T> toVector()

Description copied from class: ACollection

Converts this collection to a canonical vector of elements

Specified by:

toVector in class ACollection<T extends ACell>

Returns:

This collection coerced to a vector

getRefCount

public int getRefCount()

Description copied from class: ACell

Gets the number of Refs contained within this Cell. This number is final / immutable for any given instance and is defined by the Cell encoding rules. Contained Refs may be either external or embedded.

Overrides:

getRefCount in class ACell

Returns:

The number of Refs in this Cell

getRef

public <R extends ACell> Ref<R> getRef(int i)

Description copied from class: ACell

Gets a numbered child Ref from within this Cell. WARNING: May need to convert to a canonical instance

Overrides:

getRef in class ACell

Type Parameters:

R - Type of referenced Cell

Parameters:

i - Index of ref to get

Returns:

The Ref at the specified index

updateRefs

public VectorTree<T> updateRefs(IRefFunction func)

Description copied from class: ACell

Updates all Refs in this object using the given function. The function *must not* change the hash value of Refs, in order to ensure structural integrity of modified data structures. The implementation *should* re-attach any original encoding in order to prevent re-encoding or surplus hashing This is a building block for a very sneaky trick that enables use to do a lot of efficient operations on large trees of smart references. Must return the same object if no Refs are altered.

Specified by:

updateRefs in class AVector<T extends ACell>

Parameters:

func - Ref update function

Returns:

Cell with updated Refs

commonPrefixLength

public long commonPrefixLength(AVector<T> b)

Description copied from class: AVector

Computes the length of the longest common prefix of this vector and another vector.

Specified by:

commonPrefixLength in class AVector<T extends ACell>

Parameters:

b - Any vector

Returns:

Length of the longest common prefix

getChunk

public VectorLeaf<T> getChunk(long offset)

Description copied from class: AVector

Gets the VectorLeaf chunk at a given offset

Specified by:

getChunk in class AVector<T extends ACell>

Parameters:

offset - Offset into this vector. Must be a valid chunk start position

Returns:

The chunk referenced

slice

public AVector<T> slice(long start,
 long end)

Description copied from class: ASequence

Produces a slice of this sequence, beginning with the specified start index and of the given length. The start and end must be contained within this sequence. Will return the same sequence if the start is zero and the length matches this sequence.

Specified by:

slice in class AVector<T extends ACell>

Parameters:

start - Index of the start element

end - End index(exclusive)

Returns:

A sequence representing the requested slice.

next

public AVector<T> next()

Description copied from class: ASequence

Gets the sequence of all elements after the first, or null if no elements remain after the first (i.e. count of 0 or 1)

Specified by:

next in class AVector<T extends ACell>

Returns:

Sequence following the first element

validate

public void validate()
              throws InvalidDataException

Description copied from interface: IValidated

Validates the complete structure of this object. It is necessary to ensure all child Refs are validated, so the general contract for validate is:

1. Call super.validate() - which will indirectly call validateCell()
2. Call validate() on any contained cells in this class

Specified by:

validate in interface IValidated

Overrides:

validate in class ACell

Throws:

InvalidDataException - If the data Value is invalid in any way

validateCell

public void validateCell()
                  throws InvalidDataException

Description copied from class: ACell

Validates the local structure and invariants of this cell. Called by validate() super implementation. Should validate directly contained data, but should not validate all other structure of this cell. In particular, should not traverse potentially missing child Refs.

Specified by:

validateCell in class ACell

Throws:

InvalidDataException - If the Cell is invalid

equals

public boolean equals(AVector<? super T> o)

Specified by:

equals in class AVector<T extends ACell>