package utf8
import "unicode/utf8"
Package utf8 implements functions and constants to support text encoded in UTF-8. It includes functions to translate between runes and UTF-8 byte sequences.
Index ¶
- Constants
- func DecodeLastRune(p []byte) (r rune, size int)
- func DecodeLastRuneInString(s string) (r rune, size int)
- func DecodeRune(p []byte) (r rune, size int)
- func DecodeRuneInString(s string) (r rune, size int)
- func EncodeRune(p []byte, r rune) int
- func FullRune(p []byte) bool
- func FullRuneInString(s string) bool
- func RuneCount(p []byte) int
- func RuneCountInString(s string) (n int)
- func RuneLen(r rune) int
- func RuneStart(b byte) bool
- func Valid(p []byte) bool
- func ValidRune(r rune) bool
- func ValidString(s string) bool
Examples ¶
- DecodeLastRune
- DecodeLastRuneInString
- DecodeRune
- DecodeRuneInString
- EncodeRune
- FullRune
- FullRuneInString
- RuneCount
- RuneCountInString
- RuneLen
- RuneStart
- Valid
- ValidRune
- ValidString
Constants ¶
const ( RuneError = '\uFFFD' // the "error" Rune or "Unicode replacement character" RuneSelf = 0x80 // characters below Runeself are represented as themselves in a single byte. MaxRune = '\U0010FFFF' // Maximum valid Unicode code point. UTFMax = 4 // maximum number of bytes of a UTF-8 encoded Unicode character. )
Numbers fundamental to the encoding.
Functions ¶
func DecodeLastRune ¶
DecodeLastRune unpacks the last UTF-8 encoding in p and returns the rune and its width in bytes. If p is empty it returns (RuneError, 0). Otherwise, if the encoding is invalid, it returns (RuneError, 1). Both are impossible results for correct UTF-8.
An encoding is invalid if it is incorrect UTF-8, encodes a rune that is out of range, or is not the shortest possible UTF-8 encoding for the value. No other validation is performed.
func DecodeLastRuneInString ¶
DecodeLastRuneInString is like DecodeLastRune but its input is a string. If s is empty it returns (RuneError, 0). Otherwise, if the encoding is invalid, it returns (RuneError, 1). Both are impossible results for correct UTF-8.
An encoding is invalid if it is incorrect UTF-8, encodes a rune that is out of range, or is not the shortest possible UTF-8 encoding for the value. No other validation is performed.
func DecodeRune ¶
DecodeRune unpacks the first UTF-8 encoding in p and returns the rune and its width in bytes. If p is empty it returns (RuneError, 0). Otherwise, if the encoding is invalid, it returns (RuneError, 1). Both are impossible results for correct UTF-8.
An encoding is invalid if it is incorrect UTF-8, encodes a rune that is out of range, or is not the shortest possible UTF-8 encoding for the value. No other validation is performed.
func DecodeRuneInString ¶
DecodeRuneInString is like DecodeRune but its input is a string. If s is empty it returns (RuneError, 0). Otherwise, if the encoding is invalid, it returns (RuneError, 1). Both are impossible results for correct UTF-8.
An encoding is invalid if it is incorrect UTF-8, encodes a rune that is out of range, or is not the shortest possible UTF-8 encoding for the value. No other validation is performed.
func EncodeRune ¶
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 ¶
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 ¶
FullRuneInString is like FullRune but its input is a string.
func RuneCount ¶
RuneCount returns the number of runes in p. Erroneous and short encodings are treated as single runes of width 1 byte.
func RuneCountInString ¶
RuneCountInString is like RuneCount but its input is a string.
func RuneLen ¶
RuneLen returns the number of bytes required to encode the rune. It returns -1 if the rune is not a valid value to encode in UTF-8.
func RuneStart ¶
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.
func Valid ¶
Valid reports whether p consists entirely of valid UTF-8-encoded runes.
func ValidRune ¶
ValidRune reports whether r can be legally encoded as UTF-8. Code points that are out of range or a surrogate half are illegal.
func ValidString ¶
ValidString reports whether s consists entirely of valid UTF-8-encoded runes.
Source Files ¶
- Version
- v1.5.0-beta.3
- Published
- Jul 30, 2015
- Platform
- darwin/amd64
- Last checked
- 2 minutes ago –
Tools for package owners.