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Diffstat (limited to 'vendor/golang.org/x/text/secure/bidirule/bidirule.go')
| -rw-r--r-- | vendor/golang.org/x/text/secure/bidirule/bidirule.go | 336 |
1 files changed, 0 insertions, 336 deletions
diff --git a/vendor/golang.org/x/text/secure/bidirule/bidirule.go b/vendor/golang.org/x/text/secure/bidirule/bidirule.go deleted file mode 100644 index e2b70f7..0000000 --- a/vendor/golang.org/x/text/secure/bidirule/bidirule.go +++ /dev/null @@ -1,336 +0,0 @@ -// Copyright 2016 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// Package bidirule implements the Bidi Rule defined by RFC 5893. -// -// This package is under development. The API may change without notice and -// without preserving backward compatibility. -package bidirule - -import ( - "errors" - "unicode/utf8" - - "golang.org/x/text/transform" - "golang.org/x/text/unicode/bidi" -) - -// This file contains an implementation of RFC 5893: Right-to-Left Scripts for -// Internationalized Domain Names for Applications (IDNA) -// -// A label is an individual component of a domain name. Labels are usually -// shown separated by dots; for example, the domain name "www.example.com" is -// composed of three labels: "www", "example", and "com". -// -// An RTL label is a label that contains at least one character of class R, AL, -// or AN. An LTR label is any label that is not an RTL label. -// -// A "Bidi domain name" is a domain name that contains at least one RTL label. -// -// The following guarantees can be made based on the above: -// -// o In a domain name consisting of only labels that satisfy the rule, -// the requirements of Section 3 are satisfied. Note that even LTR -// labels and pure ASCII labels have to be tested. -// -// o In a domain name consisting of only LDH labels (as defined in the -// Definitions document [RFC5890]) and labels that satisfy the rule, -// the requirements of Section 3 are satisfied as long as a label -// that starts with an ASCII digit does not come after a -// right-to-left label. -// -// No guarantee is given for other combinations. - -// ErrInvalid indicates a label is invalid according to the Bidi Rule. -var ErrInvalid = errors.New("bidirule: failed Bidi Rule") - -type ruleState uint8 - -const ( - ruleInitial ruleState = iota - ruleLTR - ruleLTRFinal - ruleRTL - ruleRTLFinal - ruleInvalid -) - -type ruleTransition struct { - next ruleState - mask uint16 -} - -var transitions = [...][2]ruleTransition{ - // [2.1] The first character must be a character with Bidi property L, R, or - // AL. If it has the R or AL property, it is an RTL label; if it has the L - // property, it is an LTR label. - ruleInitial: { - {ruleLTRFinal, 1 << bidi.L}, - {ruleRTLFinal, 1<<bidi.R | 1<<bidi.AL}, - }, - ruleRTL: { - // [2.3] In an RTL label, the end of the label must be a character with - // Bidi property R, AL, EN, or AN, followed by zero or more characters - // with Bidi property NSM. - {ruleRTLFinal, 1<<bidi.R | 1<<bidi.AL | 1<<bidi.EN | 1<<bidi.AN}, - - // [2.2] In an RTL label, only characters with the Bidi properties R, - // AL, AN, EN, ES, CS, ET, ON, BN, or NSM are allowed. - // We exclude the entries from [2.3] - {ruleRTL, 1<<bidi.ES | 1<<bidi.CS | 1<<bidi.ET | 1<<bidi.ON | 1<<bidi.BN | 1<<bidi.NSM}, - }, - ruleRTLFinal: { - // [2.3] In an RTL label, the end of the label must be a character with - // Bidi property R, AL, EN, or AN, followed by zero or more characters - // with Bidi property NSM. - {ruleRTLFinal, 1<<bidi.R | 1<<bidi.AL | 1<<bidi.EN | 1<<bidi.AN | 1<<bidi.NSM}, - - // [2.2] In an RTL label, only characters with the Bidi properties R, - // AL, AN, EN, ES, CS, ET, ON, BN, or NSM are allowed. - // We exclude the entries from [2.3] and NSM. - {ruleRTL, 1<<bidi.ES | 1<<bidi.CS | 1<<bidi.ET | 1<<bidi.ON | 1<<bidi.BN}, - }, - ruleLTR: { - // [2.6] In an LTR label, the end of the label must be a character with - // Bidi property L or EN, followed by zero or more characters with Bidi - // property NSM. - {ruleLTRFinal, 1<<bidi.L | 1<<bidi.EN}, - - // [2.5] In an LTR label, only characters with the Bidi properties L, - // EN, ES, CS, ET, ON, BN, or NSM are allowed. - // We exclude the entries from [2.6]. - {ruleLTR, 1<<bidi.ES | 1<<bidi.CS | 1<<bidi.ET | 1<<bidi.ON | 1<<bidi.BN | 1<<bidi.NSM}, - }, - ruleLTRFinal: { - // [2.6] In an LTR label, the end of the label must be a character with - // Bidi property L or EN, followed by zero or more characters with Bidi - // property NSM. - {ruleLTRFinal, 1<<bidi.L | 1<<bidi.EN | 1<<bidi.NSM}, - - // [2.5] In an LTR label, only characters with the Bidi properties L, - // EN, ES, CS, ET, ON, BN, or NSM are allowed. - // We exclude the entries from [2.6]. - {ruleLTR, 1<<bidi.ES | 1<<bidi.CS | 1<<bidi.ET | 1<<bidi.ON | 1<<bidi.BN}, - }, - ruleInvalid: { - {ruleInvalid, 0}, - {ruleInvalid, 0}, - }, -} - -// [2.4] In an RTL label, if an EN is present, no AN may be present, and -// vice versa. -const exclusiveRTL = uint16(1<<bidi.EN | 1<<bidi.AN) - -// From RFC 5893 -// An RTL label is a label that contains at least one character of type -// R, AL, or AN. -// -// An LTR label is any label that is not an RTL label. - -// Direction reports the direction of the given label as defined by RFC 5893. -// The Bidi Rule does not have to be applied to labels of the category -// LeftToRight. -func Direction(b []byte) bidi.Direction { - for i := 0; i < len(b); { - e, sz := bidi.Lookup(b[i:]) - if sz == 0 { - i++ - } - c := e.Class() - if c == bidi.R || c == bidi.AL || c == bidi.AN { - return bidi.RightToLeft - } - i += sz - } - return bidi.LeftToRight -} - -// DirectionString reports the direction of the given label as defined by RFC -// 5893. The Bidi Rule does not have to be applied to labels of the category -// LeftToRight. -func DirectionString(s string) bidi.Direction { - for i := 0; i < len(s); { - e, sz := bidi.LookupString(s[i:]) - if sz == 0 { - i++ - continue - } - c := e.Class() - if c == bidi.R || c == bidi.AL || c == bidi.AN { - return bidi.RightToLeft - } - i += sz - } - return bidi.LeftToRight -} - -// Valid reports whether b conforms to the BiDi rule. -func Valid(b []byte) bool { - var t Transformer - if n, ok := t.advance(b); !ok || n < len(b) { - return false - } - return t.isFinal() -} - -// ValidString reports whether s conforms to the BiDi rule. -func ValidString(s string) bool { - var t Transformer - if n, ok := t.advanceString(s); !ok || n < len(s) { - return false - } - return t.isFinal() -} - -// New returns a Transformer that verifies that input adheres to the Bidi Rule. -func New() *Transformer { - return &Transformer{} -} - -// Transformer implements transform.Transform. -type Transformer struct { - state ruleState - hasRTL bool - seen uint16 -} - -// A rule can only be violated for "Bidi Domain names", meaning if one of the -// following categories has been observed. -func (t *Transformer) isRTL() bool { - const isRTL = 1<<bidi.R | 1<<bidi.AL | 1<<bidi.AN - return t.seen&isRTL != 0 -} - -// Reset implements transform.Transformer. -func (t *Transformer) Reset() { *t = Transformer{} } - -// Transform implements transform.Transformer. This Transformer has state and -// needs to be reset between uses. -func (t *Transformer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { - if len(dst) < len(src) { - src = src[:len(dst)] - atEOF = false - err = transform.ErrShortDst - } - n, err1 := t.Span(src, atEOF) - copy(dst, src[:n]) - if err == nil || err1 != nil && err1 != transform.ErrShortSrc { - err = err1 - } - return n, n, err -} - -// Span returns the first n bytes of src that conform to the Bidi rule. -func (t *Transformer) Span(src []byte, atEOF bool) (n int, err error) { - if t.state == ruleInvalid && t.isRTL() { - return 0, ErrInvalid - } - n, ok := t.advance(src) - switch { - case !ok: - err = ErrInvalid - case n < len(src): - if !atEOF { - err = transform.ErrShortSrc - break - } - err = ErrInvalid - case !t.isFinal(): - err = ErrInvalid - } - return n, err -} - -// Precomputing the ASCII values decreases running time for the ASCII fast path -// by about 30%. -var asciiTable [128]bidi.Properties - -func init() { - for i := range asciiTable { - p, _ := bidi.LookupRune(rune(i)) - asciiTable[i] = p - } -} - -func (t *Transformer) advance(s []byte) (n int, ok bool) { - var e bidi.Properties - var sz int - for n < len(s) { - if s[n] < utf8.RuneSelf { - e, sz = asciiTable[s[n]], 1 - } else { - e, sz = bidi.Lookup(s[n:]) - if sz <= 1 { - if sz == 1 { - // We always consider invalid UTF-8 to be invalid, even if - // the string has not yet been determined to be RTL. - // TODO: is this correct? - return n, false - } - return n, true // incomplete UTF-8 encoding - } - } - // TODO: using CompactClass would result in noticeable speedup. - // See unicode/bidi/prop.go:Properties.CompactClass. - c := uint16(1 << e.Class()) - t.seen |= c - if t.seen&exclusiveRTL == exclusiveRTL { - t.state = ruleInvalid - return n, false - } - switch tr := transitions[t.state]; { - case tr[0].mask&c != 0: - t.state = tr[0].next - case tr[1].mask&c != 0: - t.state = tr[1].next - default: - t.state = ruleInvalid - if t.isRTL() { - return n, false - } - } - n += sz - } - return n, true -} - -func (t *Transformer) advanceString(s string) (n int, ok bool) { - var e bidi.Properties - var sz int - for n < len(s) { - if s[n] < utf8.RuneSelf { - e, sz = asciiTable[s[n]], 1 - } else { - e, sz = bidi.LookupString(s[n:]) - if sz <= 1 { - if sz == 1 { - return n, false // invalid UTF-8 - } - return n, true // incomplete UTF-8 encoding - } - } - // TODO: using CompactClass results in noticeable speedup. - // See unicode/bidi/prop.go:Properties.CompactClass. - c := uint16(1 << e.Class()) - t.seen |= c - if t.seen&exclusiveRTL == exclusiveRTL { - t.state = ruleInvalid - return n, false - } - switch tr := transitions[t.state]; { - case tr[0].mask&c != 0: - t.state = tr[0].next - case tr[1].mask&c != 0: - t.state = tr[1].next - default: - t.state = ruleInvalid - if t.isRTL() { - return n, false - } - } - n += sz - } - return n, true -} |