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Diffstat (limited to 'vendor/golang.org/x/text/unicode/bidi/bidi.go')
| -rw-r--r-- | vendor/golang.org/x/text/unicode/bidi/bidi.go | 359 |
1 files changed, 0 insertions, 359 deletions
diff --git a/vendor/golang.org/x/text/unicode/bidi/bidi.go b/vendor/golang.org/x/text/unicode/bidi/bidi.go deleted file mode 100644 index fd057601b..000000000 --- a/vendor/golang.org/x/text/unicode/bidi/bidi.go +++ /dev/null @@ -1,359 +0,0 @@ -// Copyright 2015 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. - -//go:generate go run gen.go gen_trieval.go gen_ranges.go - -// Package bidi contains functionality for bidirectional text support. -// -// See https://www.unicode.org/reports/tr9. -// -// NOTE: UNDER CONSTRUCTION. This API may change in backwards incompatible ways -// and without notice. -package bidi // import "golang.org/x/text/unicode/bidi" - -// TODO -// - Transformer for reordering? -// - Transformer (validator, really) for Bidi Rule. - -import ( - "bytes" -) - -// This API tries to avoid dealing with embedding levels for now. Under the hood -// these will be computed, but the question is to which extent the user should -// know they exist. We should at some point allow the user to specify an -// embedding hierarchy, though. - -// A Direction indicates the overall flow of text. -type Direction int - -const ( - // LeftToRight indicates the text contains no right-to-left characters and - // that either there are some left-to-right characters or the option - // DefaultDirection(LeftToRight) was passed. - LeftToRight Direction = iota - - // RightToLeft indicates the text contains no left-to-right characters and - // that either there are some right-to-left characters or the option - // DefaultDirection(RightToLeft) was passed. - RightToLeft - - // Mixed indicates text contains both left-to-right and right-to-left - // characters. - Mixed - - // Neutral means that text contains no left-to-right and right-to-left - // characters and that no default direction has been set. - Neutral -) - -type options struct { - defaultDirection Direction -} - -// An Option is an option for Bidi processing. -type Option func(*options) - -// ICU allows the user to define embedding levels. This may be used, for example, -// to use hierarchical structure of markup languages to define embeddings. -// The following option may be a way to expose this functionality in this API. -// // LevelFunc sets a function that associates nesting levels with the given text. -// // The levels function will be called with monotonically increasing values for p. -// func LevelFunc(levels func(p int) int) Option { -// panic("unimplemented") -// } - -// DefaultDirection sets the default direction for a Paragraph. The direction is -// overridden if the text contains directional characters. -func DefaultDirection(d Direction) Option { - return func(opts *options) { - opts.defaultDirection = d - } -} - -// A Paragraph holds a single Paragraph for Bidi processing. -type Paragraph struct { - p []byte - o Ordering - opts []Option - types []Class - pairTypes []bracketType - pairValues []rune - runes []rune - options options -} - -// Initialize the p.pairTypes, p.pairValues and p.types from the input previously -// set by p.SetBytes() or p.SetString(). Also limit the input up to (and including) a paragraph -// separator (bidi class B). -// -// The function p.Order() needs these values to be set, so this preparation could be postponed. -// But since the SetBytes and SetStrings functions return the length of the input up to the paragraph -// separator, the whole input needs to be processed anyway and should not be done twice. -// -// The function has the same return values as SetBytes() / SetString() -func (p *Paragraph) prepareInput() (n int, err error) { - p.runes = bytes.Runes(p.p) - bytecount := 0 - // clear slices from previous SetString or SetBytes - p.pairTypes = nil - p.pairValues = nil - p.types = nil - - for _, r := range p.runes { - props, i := LookupRune(r) - bytecount += i - cls := props.Class() - if cls == B { - return bytecount, nil - } - p.types = append(p.types, cls) - if props.IsOpeningBracket() { - p.pairTypes = append(p.pairTypes, bpOpen) - p.pairValues = append(p.pairValues, r) - } else if props.IsBracket() { - // this must be a closing bracket, - // since IsOpeningBracket is not true - p.pairTypes = append(p.pairTypes, bpClose) - p.pairValues = append(p.pairValues, r) - } else { - p.pairTypes = append(p.pairTypes, bpNone) - p.pairValues = append(p.pairValues, 0) - } - } - return bytecount, nil -} - -// SetBytes configures p for the given paragraph text. It replaces text -// previously set by SetBytes or SetString. If b contains a paragraph separator -// it will only process the first paragraph and report the number of bytes -// consumed from b including this separator. Error may be non-nil if options are -// given. -func (p *Paragraph) SetBytes(b []byte, opts ...Option) (n int, err error) { - p.p = b - p.opts = opts - return p.prepareInput() -} - -// SetString configures s for the given paragraph text. It replaces text -// previously set by SetBytes or SetString. If s contains a paragraph separator -// it will only process the first paragraph and report the number of bytes -// consumed from s including this separator. Error may be non-nil if options are -// given. -func (p *Paragraph) SetString(s string, opts ...Option) (n int, err error) { - p.p = []byte(s) - p.opts = opts - return p.prepareInput() -} - -// IsLeftToRight reports whether the principle direction of rendering for this -// paragraphs is left-to-right. If this returns false, the principle direction -// of rendering is right-to-left. -func (p *Paragraph) IsLeftToRight() bool { - return p.Direction() == LeftToRight -} - -// Direction returns the direction of the text of this paragraph. -// -// The direction may be LeftToRight, RightToLeft, Mixed, or Neutral. -func (p *Paragraph) Direction() Direction { - return p.o.Direction() -} - -// TODO: what happens if the position is > len(input)? This should return an error. - -// RunAt reports the Run at the given position of the input text. -// -// This method can be used for computing line breaks on paragraphs. -func (p *Paragraph) RunAt(pos int) Run { - c := 0 - runNumber := 0 - for i, r := range p.o.runes { - c += len(r) - if pos < c { - runNumber = i - } - } - return p.o.Run(runNumber) -} - -func calculateOrdering(levels []level, runes []rune) Ordering { - var curDir Direction - - prevDir := Neutral - prevI := 0 - - o := Ordering{} - // lvl = 0,2,4,...: left to right - // lvl = 1,3,5,...: right to left - for i, lvl := range levels { - if lvl%2 == 0 { - curDir = LeftToRight - } else { - curDir = RightToLeft - } - if curDir != prevDir { - if i > 0 { - o.runes = append(o.runes, runes[prevI:i]) - o.directions = append(o.directions, prevDir) - o.startpos = append(o.startpos, prevI) - } - prevI = i - prevDir = curDir - } - } - o.runes = append(o.runes, runes[prevI:]) - o.directions = append(o.directions, prevDir) - o.startpos = append(o.startpos, prevI) - return o -} - -// Order computes the visual ordering of all the runs in a Paragraph. -func (p *Paragraph) Order() (Ordering, error) { - if len(p.types) == 0 { - return Ordering{}, nil - } - - for _, fn := range p.opts { - fn(&p.options) - } - lvl := level(-1) - if p.options.defaultDirection == RightToLeft { - lvl = 1 - } - para, err := newParagraph(p.types, p.pairTypes, p.pairValues, lvl) - if err != nil { - return Ordering{}, err - } - - levels := para.getLevels([]int{len(p.types)}) - - p.o = calculateOrdering(levels, p.runes) - return p.o, nil -} - -// Line computes the visual ordering of runs for a single line starting and -// ending at the given positions in the original text. -func (p *Paragraph) Line(start, end int) (Ordering, error) { - lineTypes := p.types[start:end] - para, err := newParagraph(lineTypes, p.pairTypes[start:end], p.pairValues[start:end], -1) - if err != nil { - return Ordering{}, err - } - levels := para.getLevels([]int{len(lineTypes)}) - o := calculateOrdering(levels, p.runes[start:end]) - return o, nil -} - -// An Ordering holds the computed visual order of runs of a Paragraph. Calling -// SetBytes or SetString on the originating Paragraph invalidates an Ordering. -// The methods of an Ordering should only be called by one goroutine at a time. -type Ordering struct { - runes [][]rune - directions []Direction - startpos []int -} - -// Direction reports the directionality of the runs. -// -// The direction may be LeftToRight, RightToLeft, Mixed, or Neutral. -func (o *Ordering) Direction() Direction { - return o.directions[0] -} - -// NumRuns returns the number of runs. -func (o *Ordering) NumRuns() int { - return len(o.runes) -} - -// Run returns the ith run within the ordering. -func (o *Ordering) Run(i int) Run { - r := Run{ - runes: o.runes[i], - direction: o.directions[i], - startpos: o.startpos[i], - } - return r -} - -// TODO: perhaps with options. -// // Reorder creates a reader that reads the runes in visual order per character. -// // Modifiers remain after the runes they modify. -// func (l *Runs) Reorder() io.Reader { -// panic("unimplemented") -// } - -// A Run is a continuous sequence of characters of a single direction. -type Run struct { - runes []rune - direction Direction - startpos int -} - -// String returns the text of the run in its original order. -func (r *Run) String() string { - return string(r.runes) -} - -// Bytes returns the text of the run in its original order. -func (r *Run) Bytes() []byte { - return []byte(r.String()) -} - -// TODO: methods for -// - Display order -// - headers and footers -// - bracket replacement. - -// Direction reports the direction of the run. -func (r *Run) Direction() Direction { - return r.direction -} - -// Pos returns the position of the Run within the text passed to SetBytes or SetString of the -// originating Paragraph value. -func (r *Run) Pos() (start, end int) { - return r.startpos, r.startpos + len(r.runes) - 1 -} - -// AppendReverse reverses the order of characters of in, appends them to out, -// and returns the result. Modifiers will still follow the runes they modify. -// Brackets are replaced with their counterparts. -func AppendReverse(out, in []byte) []byte { - ret := make([]byte, len(in)+len(out)) - copy(ret, out) - inRunes := bytes.Runes(in) - - for i, r := range inRunes { - prop, _ := LookupRune(r) - if prop.IsBracket() { - inRunes[i] = prop.reverseBracket(r) - } - } - - for i, j := 0, len(inRunes)-1; i < j; i, j = i+1, j-1 { - inRunes[i], inRunes[j] = inRunes[j], inRunes[i] - } - copy(ret[len(out):], string(inRunes)) - - return ret -} - -// ReverseString reverses the order of characters in s and returns a new string. -// Modifiers will still follow the runes they modify. Brackets are replaced with -// their counterparts. -func ReverseString(s string) string { - input := []rune(s) - li := len(input) - ret := make([]rune, li) - for i, r := range input { - prop, _ := LookupRune(r) - if prop.IsBracket() { - ret[li-i-1] = prop.reverseBracket(r) - } else { - ret[li-i-1] = r - } - } - return string(ret) -} |