import "golang.org/x/text/unicode/norm"
Package norm contains types and functions for normalizing Unicode strings.
composition.go forminfo.go input.go iter.go normalize.go readwriter.go tables.go transform.go trie.go
const (
// Version is the Unicode edition from which the tables are derived.
Version = "8.0.0"
// MaxTransformChunkSize indicates the maximum number of bytes that Transform
// may need to write atomically for any Form. Making a destination buffer at
// least this size ensures that Transform can always make progress and that
// the user does not need to grow the buffer on an ErrShortDst.
MaxTransformChunkSize = 35 + maxNonStarters*4
)const GraphemeJoiner = "\u034F"GraphemeJoiner is inserted after maxNonStarters non-starter runes.
const MaxSegmentSize = maxByteBufferSizeMaxSegmentSize is the maximum size of a byte buffer needed to consider any sequence of starter and non-starter runes for the purpose of normalization.
A Form denotes a canonical representation of Unicode code points. The Unicode-defined normalization and equivalence forms are:
NFC Unicode Normalization Form C NFD Unicode Normalization Form D NFKC Unicode Normalization Form KC NFKD Unicode Normalization Form KD
For a Form f, this documentation uses the notation f(x) to mean the bytes or string x converted to the given form. A position n in x is called a boundary if conversion to the form can proceed independently on both sides:
f(x) == append(f(x[0:n]), f(x[n:])...)
References: http://unicode.org/reports/tr15/ and http://unicode.org/notes/tn5/.
Append returns f(append(out, b...)). The buffer out must be nil, empty, or equal to f(out).
AppendString returns f(append(out, []byte(s))). The buffer out must be nil, empty, or equal to f(out).
Bytes returns f(b). May return b if f(b) = b.
FirstBoundary returns the position i of the first boundary in b or -1 if b contains no boundary.
FirstBoundaryInString returns the position i of the first boundary in s or -1 if s contains no boundary.
IsNormal returns true if b == f(b).
IsNormalString returns true if s == f(s).
LastBoundary returns the position i of the last boundary in b or -1 if b contains no boundary.
func (f Form) Properties(s []byte) Properties
Properties returns properties for the first rune in s.
func (f Form) PropertiesString(s string) Properties
PropertiesString returns properties for the first rune in s.
QuickSpan returns a boundary n such that b[0:n] == f(b[0:n]). It is not guaranteed to return the largest such n.
QuickSpanString returns a boundary n such that b[0:n] == f(s[0:n]). It is not guaranteed to return the largest such n.
Reader returns a new reader that implements Read by reading data from r and returning f(data).
Reset implements the Reset method of the transform.Transformer interface.
String returns f(s).
Transform implements the Transform method of the transform.Transformer interface. It may need to write segments of up to MaxSegmentSize at once. Users should either catch ErrShortDst and allow dst to grow or have dst be at least of size MaxTransformChunkSize to be guaranteed of progress.
Writer returns a new writer that implements Write(b) by writing f(b) to w. The returned writer may use an an internal buffer to maintain state across Write calls. Calling its Close method writes any buffered data to w.
type Iter struct {
// contains filtered or unexported fields
}An Iter iterates over a string or byte slice, while normalizing it to a given Form.
Code:
package main
import (
"bytes"
"fmt"
"unicode/utf8"
"golang.org/x/text/unicode/norm"
)
// EqualSimple uses a norm.Iter to compare two non-normalized
// strings for equivalence.
func EqualSimple(a, b string) bool {
var ia, ib norm.Iter
ia.InitString(norm.NFKD, a)
ib.InitString(norm.NFKD, b)
for !ia.Done() && !ib.Done() {
if !bytes.Equal(ia.Next(), ib.Next()) {
return false
}
}
return ia.Done() && ib.Done()
}
// FindPrefix finds the longest common prefix of ASCII characters
// of a and b.
func FindPrefix(a, b string) int {
i := 0
for ; i < len(a) && i < len(b) && a[i] < utf8.RuneSelf && a[i] == b[i]; i++ {
}
return i
}
// EqualOpt is like EqualSimple, but optimizes the special
// case for ASCII characters.
func EqualOpt(a, b string) bool {
n := FindPrefix(a, b)
a, b = a[n:], b[n:]
var ia, ib norm.Iter
ia.InitString(norm.NFKD, a)
ib.InitString(norm.NFKD, b)
for !ia.Done() && !ib.Done() {
if !bytes.Equal(ia.Next(), ib.Next()) {
return false
}
if n := int64(FindPrefix(a[ia.Pos():], b[ib.Pos():])); n != 0 {
ia.Seek(n, 1)
ib.Seek(n, 1)
}
}
return ia.Done() && ib.Done()
}
var compareTests = []struct{ a, b string }{
{"aaa", "aaa"},
{"aaa", "aab"},
{"a\u0300a", "\u00E0a"},
{"a\u0300\u0320b", "a\u0320\u0300b"},
{"\u1E0A\u0323", "\x44\u0323\u0307"},
// A character that decomposes into multiple segments
// spans several iterations.
{"\u3304", "\u30A4\u30CB\u30F3\u30AF\u3099"},
}
func main() {
for i, t := range compareTests {
r0 := EqualSimple(t.a, t.b)
r1 := EqualOpt(t.a, t.b)
fmt.Printf("%d: %v %v\n", i, r0, r1)
}
}
Done returns true if there is no more input to process.
Init initializes i to iterate over src after normalizing it to Form f.
InitString initializes i to iterate over src after normalizing it to Form f.
Next returns f(i.input[i.Pos():n]), where n is a boundary of i.input. For any input a and b for which f(a) == f(b), subsequent calls to Next will return the same segments. Modifying runes are grouped together with the preceding starter, if such a starter exists. Although not guaranteed, n will typically be the smallest possible n.
Pos returns the byte position at which the next call to Next will commence processing.
Seek sets the segment to be returned by the next call to Next to start at position p. It is the responsibility of the caller to set p to the start of a UTF8 rune.
type Properties struct {
// contains filtered or unexported fields
}Properties provides access to normalization properties of a rune.
func (p Properties) BoundaryAfter() bool
BoundaryAfter returns true if runes cannot combine with or otherwise interact with this or previous runes.
func (p Properties) BoundaryBefore() bool
BoundaryBefore returns true if this rune starts a new segment and cannot combine with any rune on the left.
func (p Properties) CCC() uint8
CCC returns the canonical combining class of the underlying rune.
func (p Properties) Decomposition() []byte
Decomposition returns the decomposition for the underlying rune or nil if there is none.
func (p Properties) LeadCCC() uint8
LeadCCC returns the CCC of the first rune in the decomposition. If there is no decomposition, LeadCCC equals CCC.
func (p Properties) Size() int
Size returns the length of UTF-8 encoding of the rune.
func (p Properties) TrailCCC() uint8
TrailCCC returns the CCC of the last rune in the decomposition. If there is no decomposition, TrailCCC equals CCC.
Package norm imports 4 packages (graph) and is imported by 71 packages. Updated about 4 hours ago. Refresh now. Tools for package owners.