Package convex.core.data.prim

Class CVMChar

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.data.prim.APrimitive

convex.core.data.prim.CVMChar

All Implemented Interfaces:

IValidated, IWriteable, Comparable<CVMChar>

public final class CVMChar
extends APrimitive
implements Comparable<CVMChar>

Class for CVM Character values. Characters are Unicode code points, and can be used to construct Strings on the CVM. Limited to range 0 .. 0x10ffff as per Unicode standard

Field Summary

Fields

Modifier and Type	Field	Description
static int	MAX_CODEPOINT
static final int	MAX_UTF_BYTES	Maximum number of UTF-8 bytes required to represent a CVMChar
static CVMChar	MAX_VALUE
static final CVMChar	ZERO	Singleton instance representing the NULL character (code point zero)

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
static int	byteCountFromTag(byte tag)	Get the number of UTF-8 bytes as encoded within the encoding tag
char	charValue()	Gets the Java char value of this CVM Character.
static int	codepointFromUTFInt(int utf)	Gets a code point value from bytes encoded in a Java integer (starting from high byte)
int	compareTo(CVMChar o)
static CVMChar	create(long value)	Gets a CVMChar for the given Unicode code point, or null if not valid
double	doubleValue()
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(ACell a)	Checks for equality with another Cell.
boolean	equals(CVMChar a)
int	estimatedEncodingSize()	Estimate the encoded data size for this Cell.
static CVMChar	fromUTF8(ABlobLike<?> b)	Gets a CVMChar from a UTF-8 representation
int	getCodePoint()	Gets the Unicode code point for this Character
byte	getTag()	Gets the tag byte for this cell.
AType	getType()	Gets the most specific known runtime Type for this Cell.
int	hashCode()	Gets the Java hashCode for this cell.
long	longValue()	Gets the Long value of this char, equal to the Unicode code point
static CVMChar	parse(String s)	Parses a Character from a Java String, as interpreted by the Reader e.g.
boolean	print(BlobBuilder bb, long limit)	Prints this Object to a readable String Representation.
static CVMChar	read(int len, Blob blob, int pos)	Reads char data from Blob
AString	toCVMString(long limit)	Returns the CVM String representation of this Cell.
String	toString()	Returns the Java String representation of this CVMChar.
Blob	toUTFBlob()	Gets the Blob representation of this Character in UTF-8
byte[]	toUTFBytes()	Converts this Character to a Blob with its UTF-8 byte representation
static int	utfLength(long c)	Gets the UTF-8 length in bytes for this CVMChar
void	validateCell()	Validates the local structure and invariants of this cell.

Methods inherited from class convex.core.data.prim.APrimitive

calcMemorySize, getRef, getRefCount, isCanonical, isCVMValue, isDataValue, isEmbedded, toCanonical, updateRefs

Methods inherited from class convex.core.data.ACell

attachMemorySize, attachRef, cachedEncoding, cachedHash, createEncoding, createRef, equals, genericEquals, getCanonical, getChildRefs, getEncoding, getEncodingLength, getHash, getMemorySize, getMemorySize, getRef, validate

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

Field Details

MAX_CODEPOINT

public static int MAX_CODEPOINT

MAX_VALUE

public static CVMChar MAX_VALUE

ZERO

public static final CVMChar ZERO

Singleton instance representing the NULL character (code point zero)

MAX_UTF_BYTES

public static final int MAX_UTF_BYTES

Maximum number of UTF-8 bytes required to represent a CVMChar

See Also:

• Constant Field Values

Method Details

getType

public AType getType()

Description copied from class: ACell

Gets the most specific known runtime Type for this Cell.

Overrides:

getType in class ACell

Returns:

The Type of this Call

create

public static CVMChar create(long value)

Gets a CVMChar for the given Unicode code point, or null if not valid

Parameters:

value - Unicode code point for the character

Returns:

CVMChar instance, or null if not valid

fromUTF8

public static CVMChar fromUTF8(ABlobLike<?> b)

Gets a CVMChar from a UTF-8 representation

Parameters:

b - Representation of a single character (UTF-8)

Returns:

CVMChar instance, or null if not valid

longValue

public long longValue()

Gets the Long value of this char, equal to the Unicode code point

Specified by:

longValue in class APrimitive

Returns:

Java long value representing this primitive CVM value

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

Specified by:

estimatedEncodingSize in interface IWriteable

Returns:

The estimated size for the binary representation of this object.

byteCountFromTag

public static int byteCountFromTag(byte tag)

Get the number of UTF-8 bytes as encoded within the encoding tag

Parameters:

tag - Tag byte

Returns:

Number of bytes in range 1-4

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

codepointFromUTFInt

public static int codepointFromUTFInt(int utf)

Gets a code point value from bytes encoded in a Java integer (starting from high byte)

Parameters:

utf - UTF-8 encoded value in an integer, first byte in high byte.

Returns:

Unicode code point, or -1 if not valid UTF-8

utfLength

public static int utfLength(long c)

Gets the UTF-8 length in bytes for this CVMChar

Parameters:

c - Code point value

Returns:

UTF lenth or -1 if not a valid Unicode value

read

public static CVMChar read(int len,
 Blob blob,
 int pos)
                    throws BadFormatException

Reads char data from Blob

Parameters:

len - Length in UTF-8 bytes

blob - Blob to read from

pos - Position of tag

Returns:

CVMChar instance

Throws:

BadFormatException - if any format error

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 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 ACell

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

print

public boolean print(BlobBuilder bb,
 long limit)

Description copied from class: AObject

Prints this Object to a readable String Representation. SECURITY: Must halt and return false in O(1) time when limit of printing is exceeded otherwise DoS attacks may be possible.

Specified by:

print in class AObject

Parameters:

bb - BlobBuilder to append to. May be partially written if print limit exceeded

limit - Limit of printing in string bytes

Returns:

True if fully printed within limit, false otherwise

toString

public String toString()

Returns the Java String representation of this CVMChar. Returns a bad character representation in the case that the UTF code point of this Character is invalid Different from print() which returns a readable representation. For instance, on CVMChar \a, this methods returns "a" while print() returns "\a".

Overrides:

toString in class ACell

doubleValue

public double doubleValue()

Specified by:

doubleValue in class APrimitive

Returns:

Java double value representing this primitive CVM value

parse

public static CVMChar parse(String s)

Parses a Character from a Java String, as interpreted by the Reader e.g. "\newline" or "\c"

Parameters:

s - String to parse

Returns:

CVMChar instance, or null if not valid

getTag

public byte getTag()

Description copied from class: ACell

Gets the tag byte for this cell. The tag byte is always equal to the first byte of the Cell's canonical Encoding, and is sufficient to distinguish how to read the rest of the encoding.

Specified by:

getTag in class ACell

Returns:

Tag byte for this Cell

charValue

public char charValue()

Gets the Java char value of this CVM Character. Not all Unicode code points fit in a JVM char, a "bad character" value is used as replacement if this is not possible.

Returns:

Java Char, or a special bad character if not valid.

toUTFBytes

public byte[] toUTFBytes()

Converts this Character to a Blob with its UTF-8 byte representation

Returns:

byte[] array containing UTF-8 bytes

toUTFBlob

public Blob toUTFBlob()

Gets the Blob representation of this Character in UTF-8

Returns:

1-4 Bytes Blob containing UTF-8 representation of this Character

toCVMString

public AString toCVMString(long limit)

Description copied from class: ACell

Returns the CVM String representation of this Cell. Normally, this is as printed, but may be different for some types. SHOULD return null in O(1) time if the length of the CVM String can be proved to exceed the limit. MUST complete in O(limit) time and space otherwise The String representation is intended to be a easy-to-read textual representation of the Cell's data content.

Overrides:

toCVMString in class ACell

Parameters:

limit - Limit of CVM String length in UTF-8 bytes

Returns:

CVM String, or null if limit exceeded

getCodePoint

public int getCodePoint()

Gets the Unicode code point for this Character

Returns:

Code point as an int value

compareTo

public int compareTo(CVMChar o)

Specified by:

compareTo in interface Comparable<CVMChar>

equals

public boolean equals(ACell a)

Description copied from class: ACell

Checks for equality with another Cell. In general, Cells are considered equal if they have the same canonical representation, i.e. an identical encoding with the same hash value. Subclasses SHOULD override this if they have a more efficient equals implementation. MUST NOT require reads from Store.

Specified by:

equals in class ACell

Parameters:

a - Cell to compare with. May be null.

Returns:

True if this cell is equal to the other object

equals

public boolean equals(CVMChar a)

hashCode

public int hashCode()

Description copied from class: ACell

Gets the Java hashCode for this cell. Must be consistent with equals. Default is the hashCode of the Encoding blob, since this is consistent with encoding-based equality. However, different Types may provide more efficient hashcodes provided that the usual invariants are preserved

Overrides:

hashCode in class ACell

Returns:

integer hash code.