mirror of
https://github.com/go-gitea/gitea.git
synced 2024-08-20 03:23:26 +02:00
610 lines
15 KiB
Go
610 lines
15 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Note: the file data_test.go that is generated should not be checked in.
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//go:generate go run maketables.go triegen.go
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//go:generate go test -tags test
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// Package norm contains types and functions for normalizing Unicode strings.
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package norm // import "golang.org/x/text/unicode/norm"
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import (
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"unicode/utf8"
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"golang.org/x/text/transform"
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)
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// A Form denotes a canonical representation of Unicode code points.
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// The Unicode-defined normalization and equivalence forms are:
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//
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// NFC Unicode Normalization Form C
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// NFD Unicode Normalization Form D
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// NFKC Unicode Normalization Form KC
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// NFKD Unicode Normalization Form KD
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//
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// For a Form f, this documentation uses the notation f(x) to mean
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// the bytes or string x converted to the given form.
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// A position n in x is called a boundary if conversion to the form can
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// proceed independently on both sides:
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// f(x) == append(f(x[0:n]), f(x[n:])...)
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//
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// References: https://unicode.org/reports/tr15/ and
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// https://unicode.org/notes/tn5/.
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type Form int
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const (
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NFC Form = iota
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NFD
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NFKC
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NFKD
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)
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// Bytes returns f(b). May return b if f(b) = b.
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func (f Form) Bytes(b []byte) []byte {
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src := inputBytes(b)
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ft := formTable[f]
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n, ok := ft.quickSpan(src, 0, len(b), true)
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if ok {
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return b
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}
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out := make([]byte, n, len(b))
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copy(out, b[0:n])
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rb := reorderBuffer{f: *ft, src: src, nsrc: len(b), out: out, flushF: appendFlush}
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return doAppendInner(&rb, n)
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}
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// String returns f(s).
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func (f Form) String(s string) string {
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src := inputString(s)
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ft := formTable[f]
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n, ok := ft.quickSpan(src, 0, len(s), true)
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if ok {
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return s
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}
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out := make([]byte, n, len(s))
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copy(out, s[0:n])
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rb := reorderBuffer{f: *ft, src: src, nsrc: len(s), out: out, flushF: appendFlush}
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return string(doAppendInner(&rb, n))
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}
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// IsNormal returns true if b == f(b).
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func (f Form) IsNormal(b []byte) bool {
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src := inputBytes(b)
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ft := formTable[f]
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bp, ok := ft.quickSpan(src, 0, len(b), true)
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if ok {
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return true
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}
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rb := reorderBuffer{f: *ft, src: src, nsrc: len(b)}
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rb.setFlusher(nil, cmpNormalBytes)
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for bp < len(b) {
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rb.out = b[bp:]
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if bp = decomposeSegment(&rb, bp, true); bp < 0 {
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return false
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}
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bp, _ = rb.f.quickSpan(rb.src, bp, len(b), true)
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}
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return true
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}
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func cmpNormalBytes(rb *reorderBuffer) bool {
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b := rb.out
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for i := 0; i < rb.nrune; i++ {
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info := rb.rune[i]
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if int(info.size) > len(b) {
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return false
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}
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p := info.pos
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pe := p + info.size
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for ; p < pe; p++ {
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if b[0] != rb.byte[p] {
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return false
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}
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b = b[1:]
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}
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}
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return true
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}
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// IsNormalString returns true if s == f(s).
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func (f Form) IsNormalString(s string) bool {
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src := inputString(s)
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ft := formTable[f]
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bp, ok := ft.quickSpan(src, 0, len(s), true)
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if ok {
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return true
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}
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rb := reorderBuffer{f: *ft, src: src, nsrc: len(s)}
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rb.setFlusher(nil, func(rb *reorderBuffer) bool {
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for i := 0; i < rb.nrune; i++ {
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info := rb.rune[i]
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if bp+int(info.size) > len(s) {
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return false
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}
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p := info.pos
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pe := p + info.size
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for ; p < pe; p++ {
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if s[bp] != rb.byte[p] {
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return false
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}
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bp++
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}
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}
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return true
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})
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for bp < len(s) {
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if bp = decomposeSegment(&rb, bp, true); bp < 0 {
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return false
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}
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bp, _ = rb.f.quickSpan(rb.src, bp, len(s), true)
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}
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return true
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}
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// patchTail fixes a case where a rune may be incorrectly normalized
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// if it is followed by illegal continuation bytes. It returns the
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// patched buffer and whether the decomposition is still in progress.
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func patchTail(rb *reorderBuffer) bool {
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info, p := lastRuneStart(&rb.f, rb.out)
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if p == -1 || info.size == 0 {
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return true
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}
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end := p + int(info.size)
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extra := len(rb.out) - end
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if extra > 0 {
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// Potentially allocating memory. However, this only
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// happens with ill-formed UTF-8.
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x := make([]byte, 0)
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x = append(x, rb.out[len(rb.out)-extra:]...)
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rb.out = rb.out[:end]
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decomposeToLastBoundary(rb)
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rb.doFlush()
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rb.out = append(rb.out, x...)
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return false
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}
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buf := rb.out[p:]
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rb.out = rb.out[:p]
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decomposeToLastBoundary(rb)
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if s := rb.ss.next(info); s == ssStarter {
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rb.doFlush()
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rb.ss.first(info)
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} else if s == ssOverflow {
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rb.doFlush()
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rb.insertCGJ()
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rb.ss = 0
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}
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rb.insertUnsafe(inputBytes(buf), 0, info)
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return true
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}
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func appendQuick(rb *reorderBuffer, i int) int {
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if rb.nsrc == i {
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return i
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}
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end, _ := rb.f.quickSpan(rb.src, i, rb.nsrc, true)
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rb.out = rb.src.appendSlice(rb.out, i, end)
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return end
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}
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// Append returns f(append(out, b...)).
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// The buffer out must be nil, empty, or equal to f(out).
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func (f Form) Append(out []byte, src ...byte) []byte {
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return f.doAppend(out, inputBytes(src), len(src))
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}
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func (f Form) doAppend(out []byte, src input, n int) []byte {
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if n == 0 {
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return out
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}
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ft := formTable[f]
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// Attempt to do a quickSpan first so we can avoid initializing the reorderBuffer.
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if len(out) == 0 {
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p, _ := ft.quickSpan(src, 0, n, true)
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out = src.appendSlice(out, 0, p)
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if p == n {
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return out
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}
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rb := reorderBuffer{f: *ft, src: src, nsrc: n, out: out, flushF: appendFlush}
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return doAppendInner(&rb, p)
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}
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rb := reorderBuffer{f: *ft, src: src, nsrc: n}
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return doAppend(&rb, out, 0)
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}
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func doAppend(rb *reorderBuffer, out []byte, p int) []byte {
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rb.setFlusher(out, appendFlush)
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src, n := rb.src, rb.nsrc
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doMerge := len(out) > 0
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if q := src.skipContinuationBytes(p); q > p {
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// Move leading non-starters to destination.
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rb.out = src.appendSlice(rb.out, p, q)
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p = q
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doMerge = patchTail(rb)
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}
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fd := &rb.f
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if doMerge {
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var info Properties
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if p < n {
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info = fd.info(src, p)
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if !info.BoundaryBefore() || info.nLeadingNonStarters() > 0 {
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if p == 0 {
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decomposeToLastBoundary(rb)
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}
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p = decomposeSegment(rb, p, true)
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}
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}
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if info.size == 0 {
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rb.doFlush()
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// Append incomplete UTF-8 encoding.
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return src.appendSlice(rb.out, p, n)
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}
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if rb.nrune > 0 {
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return doAppendInner(rb, p)
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}
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}
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p = appendQuick(rb, p)
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return doAppendInner(rb, p)
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}
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func doAppendInner(rb *reorderBuffer, p int) []byte {
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for n := rb.nsrc; p < n; {
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p = decomposeSegment(rb, p, true)
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p = appendQuick(rb, p)
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}
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return rb.out
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}
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// AppendString returns f(append(out, []byte(s))).
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// The buffer out must be nil, empty, or equal to f(out).
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func (f Form) AppendString(out []byte, src string) []byte {
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return f.doAppend(out, inputString(src), len(src))
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}
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// QuickSpan returns a boundary n such that b[0:n] == f(b[0:n]).
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// It is not guaranteed to return the largest such n.
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func (f Form) QuickSpan(b []byte) int {
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n, _ := formTable[f].quickSpan(inputBytes(b), 0, len(b), true)
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return n
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}
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// Span implements transform.SpanningTransformer. It returns a boundary n such
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// that b[0:n] == f(b[0:n]). It is not guaranteed to return the largest such n.
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func (f Form) Span(b []byte, atEOF bool) (n int, err error) {
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n, ok := formTable[f].quickSpan(inputBytes(b), 0, len(b), atEOF)
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if n < len(b) {
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if !ok {
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err = transform.ErrEndOfSpan
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} else {
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err = transform.ErrShortSrc
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}
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}
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return n, err
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}
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// SpanString returns a boundary n such that s[0:n] == f(s[0:n]).
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// It is not guaranteed to return the largest such n.
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func (f Form) SpanString(s string, atEOF bool) (n int, err error) {
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n, ok := formTable[f].quickSpan(inputString(s), 0, len(s), atEOF)
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if n < len(s) {
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if !ok {
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err = transform.ErrEndOfSpan
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} else {
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err = transform.ErrShortSrc
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}
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}
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return n, err
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}
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// quickSpan returns a boundary n such that src[0:n] == f(src[0:n]) and
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// whether any non-normalized parts were found. If atEOF is false, n will
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// not point past the last segment if this segment might be become
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// non-normalized by appending other runes.
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func (f *formInfo) quickSpan(src input, i, end int, atEOF bool) (n int, ok bool) {
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var lastCC uint8
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ss := streamSafe(0)
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lastSegStart := i
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for n = end; i < n; {
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if j := src.skipASCII(i, n); i != j {
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i = j
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lastSegStart = i - 1
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lastCC = 0
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ss = 0
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continue
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}
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info := f.info(src, i)
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if info.size == 0 {
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if atEOF {
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// include incomplete runes
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return n, true
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}
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return lastSegStart, true
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}
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// This block needs to be before the next, because it is possible to
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// have an overflow for runes that are starters (e.g. with U+FF9E).
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switch ss.next(info) {
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case ssStarter:
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lastSegStart = i
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case ssOverflow:
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return lastSegStart, false
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case ssSuccess:
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if lastCC > info.ccc {
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return lastSegStart, false
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}
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}
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if f.composing {
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if !info.isYesC() {
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break
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}
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} else {
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if !info.isYesD() {
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break
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}
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}
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lastCC = info.ccc
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i += int(info.size)
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}
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if i == n {
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if !atEOF {
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n = lastSegStart
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}
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return n, true
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}
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return lastSegStart, false
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}
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// QuickSpanString returns a boundary n such that s[0:n] == f(s[0:n]).
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// It is not guaranteed to return the largest such n.
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func (f Form) QuickSpanString(s string) int {
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n, _ := formTable[f].quickSpan(inputString(s), 0, len(s), true)
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return n
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}
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// FirstBoundary returns the position i of the first boundary in b
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// or -1 if b contains no boundary.
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func (f Form) FirstBoundary(b []byte) int {
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return f.firstBoundary(inputBytes(b), len(b))
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}
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func (f Form) firstBoundary(src input, nsrc int) int {
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i := src.skipContinuationBytes(0)
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if i >= nsrc {
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return -1
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}
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fd := formTable[f]
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ss := streamSafe(0)
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// We should call ss.first here, but we can't as the first rune is
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// skipped already. This means FirstBoundary can't really determine
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// CGJ insertion points correctly. Luckily it doesn't have to.
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for {
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info := fd.info(src, i)
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if info.size == 0 {
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return -1
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}
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if s := ss.next(info); s != ssSuccess {
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return i
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}
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i += int(info.size)
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if i >= nsrc {
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if !info.BoundaryAfter() && !ss.isMax() {
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return -1
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}
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return nsrc
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}
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}
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}
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// FirstBoundaryInString returns the position i of the first boundary in s
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// or -1 if s contains no boundary.
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func (f Form) FirstBoundaryInString(s string) int {
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return f.firstBoundary(inputString(s), len(s))
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}
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// NextBoundary reports the index of the boundary between the first and next
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// segment in b or -1 if atEOF is false and there are not enough bytes to
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// determine this boundary.
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func (f Form) NextBoundary(b []byte, atEOF bool) int {
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return f.nextBoundary(inputBytes(b), len(b), atEOF)
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}
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// NextBoundaryInString reports the index of the boundary between the first and
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// next segment in b or -1 if atEOF is false and there are not enough bytes to
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// determine this boundary.
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func (f Form) NextBoundaryInString(s string, atEOF bool) int {
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return f.nextBoundary(inputString(s), len(s), atEOF)
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}
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func (f Form) nextBoundary(src input, nsrc int, atEOF bool) int {
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if nsrc == 0 {
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if atEOF {
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return 0
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}
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return -1
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}
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fd := formTable[f]
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info := fd.info(src, 0)
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if info.size == 0 {
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if atEOF {
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return 1
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}
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return -1
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}
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ss := streamSafe(0)
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ss.first(info)
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for i := int(info.size); i < nsrc; i += int(info.size) {
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info = fd.info(src, i)
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if info.size == 0 {
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if atEOF {
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return i
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}
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return -1
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}
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// TODO: Using streamSafe to determine the boundary isn't the same as
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// using BoundaryBefore. Determine which should be used.
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if s := ss.next(info); s != ssSuccess {
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return i
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}
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}
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if !atEOF && !info.BoundaryAfter() && !ss.isMax() {
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return -1
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}
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return nsrc
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}
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// LastBoundary returns the position i of the last boundary in b
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// or -1 if b contains no boundary.
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func (f Form) LastBoundary(b []byte) int {
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return lastBoundary(formTable[f], b)
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}
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func lastBoundary(fd *formInfo, b []byte) int {
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i := len(b)
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info, p := lastRuneStart(fd, b)
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if p == -1 {
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return -1
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}
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if info.size == 0 { // ends with incomplete rune
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if p == 0 { // starts with incomplete rune
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return -1
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}
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i = p
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info, p = lastRuneStart(fd, b[:i])
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if p == -1 { // incomplete UTF-8 encoding or non-starter bytes without a starter
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return i
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}
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}
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if p+int(info.size) != i { // trailing non-starter bytes: illegal UTF-8
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return i
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}
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if info.BoundaryAfter() {
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return i
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}
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ss := streamSafe(0)
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v := ss.backwards(info)
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for i = p; i >= 0 && v != ssStarter; i = p {
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info, p = lastRuneStart(fd, b[:i])
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if v = ss.backwards(info); v == ssOverflow {
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break
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}
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if p+int(info.size) != i {
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if p == -1 { // no boundary found
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return -1
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}
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return i // boundary after an illegal UTF-8 encoding
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}
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}
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return i
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}
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// decomposeSegment scans the first segment in src into rb. It inserts 0x034f
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// (Grapheme Joiner) when it encounters a sequence of more than 30 non-starters
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// and returns the number of bytes consumed from src or iShortDst or iShortSrc.
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func decomposeSegment(rb *reorderBuffer, sp int, atEOF bool) int {
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// Force one character to be consumed.
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info := rb.f.info(rb.src, sp)
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if info.size == 0 {
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return 0
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}
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if s := rb.ss.next(info); s == ssStarter {
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// TODO: this could be removed if we don't support merging.
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if rb.nrune > 0 {
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goto end
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}
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} else if s == ssOverflow {
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rb.insertCGJ()
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goto end
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}
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if err := rb.insertFlush(rb.src, sp, info); err != iSuccess {
|
|
return int(err)
|
|
}
|
|
for {
|
|
sp += int(info.size)
|
|
if sp >= rb.nsrc {
|
|
if !atEOF && !info.BoundaryAfter() {
|
|
return int(iShortSrc)
|
|
}
|
|
break
|
|
}
|
|
info = rb.f.info(rb.src, sp)
|
|
if info.size == 0 {
|
|
if !atEOF {
|
|
return int(iShortSrc)
|
|
}
|
|
break
|
|
}
|
|
if s := rb.ss.next(info); s == ssStarter {
|
|
break
|
|
} else if s == ssOverflow {
|
|
rb.insertCGJ()
|
|
break
|
|
}
|
|
if err := rb.insertFlush(rb.src, sp, info); err != iSuccess {
|
|
return int(err)
|
|
}
|
|
}
|
|
end:
|
|
if !rb.doFlush() {
|
|
return int(iShortDst)
|
|
}
|
|
return sp
|
|
}
|
|
|
|
// lastRuneStart returns the runeInfo and position of the last
|
|
// rune in buf or the zero runeInfo and -1 if no rune was found.
|
|
func lastRuneStart(fd *formInfo, buf []byte) (Properties, int) {
|
|
p := len(buf) - 1
|
|
for ; p >= 0 && !utf8.RuneStart(buf[p]); p-- {
|
|
}
|
|
if p < 0 {
|
|
return Properties{}, -1
|
|
}
|
|
return fd.info(inputBytes(buf), p), p
|
|
}
|
|
|
|
// decomposeToLastBoundary finds an open segment at the end of the buffer
|
|
// and scans it into rb. Returns the buffer minus the last segment.
|
|
func decomposeToLastBoundary(rb *reorderBuffer) {
|
|
fd := &rb.f
|
|
info, i := lastRuneStart(fd, rb.out)
|
|
if int(info.size) != len(rb.out)-i {
|
|
// illegal trailing continuation bytes
|
|
return
|
|
}
|
|
if info.BoundaryAfter() {
|
|
return
|
|
}
|
|
var add [maxNonStarters + 1]Properties // stores runeInfo in reverse order
|
|
padd := 0
|
|
ss := streamSafe(0)
|
|
p := len(rb.out)
|
|
for {
|
|
add[padd] = info
|
|
v := ss.backwards(info)
|
|
if v == ssOverflow {
|
|
// Note that if we have an overflow, it the string we are appending to
|
|
// is not correctly normalized. In this case the behavior is undefined.
|
|
break
|
|
}
|
|
padd++
|
|
p -= int(info.size)
|
|
if v == ssStarter || p < 0 {
|
|
break
|
|
}
|
|
info, i = lastRuneStart(fd, rb.out[:p])
|
|
if int(info.size) != p-i {
|
|
break
|
|
}
|
|
}
|
|
rb.ss = ss
|
|
// Copy bytes for insertion as we may need to overwrite rb.out.
|
|
var buf [maxBufferSize * utf8.UTFMax]byte
|
|
cp := buf[:copy(buf[:], rb.out[p:])]
|
|
rb.out = rb.out[:p]
|
|
for padd--; padd >= 0; padd-- {
|
|
info = add[padd]
|
|
rb.insertUnsafe(inputBytes(cp), 0, info)
|
|
cp = cp[info.size:]
|
|
}
|
|
}
|