utf8

Documentation

Overview

Functions and constants to support text encoded in UTF-8. This package calls a Unicode character a rune for brevity.

Index

• Constants
• func DecodeRune(p []byte) (rune, size int)
• func DecodeRuneInString(s string) (rune, size int)
• func EncodeRune(rune int, p []byte) int
• func FullRune(p []byte) bool
• func FullRuneInString(s string) bool
• func RuneCount(p []byte) int
• func RuneCountInString(s string) (n int)
• func RuneLen(rune int) int
• func RuneStart(b byte) bool

Constants

const (
	RuneError = unicode.ReplacementChar // the "error" Rune or "replacement character".
	RuneSelf  = 0x80                    // characters below Runeself are represented as themselves in a single byte.
	UTFMax    = 4                       // maximum number of bytes of a UTF-8 encoded Unicode character.
)

Numbers fundamental to the encoding.

Functions

func DecodeRune

func DecodeRune(p []byte) (rune, size int)

DecodeRune unpacks the first UTF-8 encoding in p and returns the rune and its width in bytes.

func DecodeRuneInString

func DecodeRuneInString(s string) (rune, size int)

DecodeRuneInString is like DecodeRune but its input is a string.

func EncodeRune

func EncodeRune(rune int, p []byte) int

EncodeRune writes into p (which must be large enough) the UTF-8 encoding of the rune. It returns the number of bytes written.

func FullRune

func FullRune(p []byte) bool

FullRune reports whether the bytes in p begin with a full UTF-8 encoding of a rune. An invalid encoding is considered a full Rune since it will convert as a width-1 error rune.

func FullRuneInString

func FullRuneInString(s string) bool

FullRuneInString is like FullRune but its input is a string.

func RuneCount

func RuneCount(p []byte) int

RuneCount returns the number of runes in p. Erroneous and short encodings are treated as single runes of width 1 byte.

func RuneCountInString

func RuneCountInString(s string) (n int)

RuneCountInString is like RuneCount but its input is a string.

func RuneLen

func RuneLen(rune int) int

RuneLen returns the number of bytes required to encode the rune.

func RuneStart

func RuneStart(b byte) bool

RuneStart reports whether the byte could be the first byte of an encoded rune. Second and subsequent bytes always have the top two bits set to 10.