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Diffstat (limited to 'vendor/golang.org/x/text/width/width.go')
| -rw-r--r-- | vendor/golang.org/x/text/width/width.go | 206 |
1 files changed, 0 insertions, 206 deletions
diff --git a/vendor/golang.org/x/text/width/width.go b/vendor/golang.org/x/text/width/width.go deleted file mode 100644 index f1639ca..0000000 --- a/vendor/golang.org/x/text/width/width.go +++ /dev/null @@ -1,206 +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 stringer -type=Kind -//go:generate go run gen.go gen_common.go gen_trieval.go - -// Package width provides functionality for handling different widths in text. -// -// Wide characters behave like ideographs; they tend to allow line breaks after -// each character and remain upright in vertical text layout. Narrow characters -// are kept together in words or runs that are rotated sideways in vertical text -// layout. -// -// For more information, see http://unicode.org/reports/tr11/. -package width // import "golang.org/x/text/width" - -import ( - "unicode/utf8" - - "golang.org/x/text/transform" -) - -// TODO -// 1) Reduce table size by compressing blocks. -// 2) API proposition for computing display length -// (approximation, fixed pitch only). -// 3) Implement display length. - -// Kind indicates the type of width property as defined in http://unicode.org/reports/tr11/. -type Kind int - -const ( - // Neutral characters do not occur in legacy East Asian character sets. - Neutral Kind = iota - - // EastAsianAmbiguous characters that can be sometimes wide and sometimes - // narrow and require additional information not contained in the character - // code to further resolve their width. - EastAsianAmbiguous - - // EastAsianWide characters are wide in its usual form. They occur only in - // the context of East Asian typography. These runes may have explicit - // halfwidth counterparts. - EastAsianWide - - // EastAsianNarrow characters are narrow in its usual form. They often have - // fullwidth counterparts. - EastAsianNarrow - - // Note: there exist Narrow runes that do not have fullwidth or wide - // counterparts, despite what the definition says (e.g. U+27E6). - - // EastAsianFullwidth characters have a compatibility decompositions of type - // wide that map to a narrow counterpart. - EastAsianFullwidth - - // EastAsianHalfwidth characters have a compatibility decomposition of type - // narrow that map to a wide or ambiguous counterpart, plus U+20A9 ₩ WON - // SIGN. - EastAsianHalfwidth - - // Note: there exist runes that have a halfwidth counterparts but that are - // classified as Ambiguous, rather than wide (e.g. U+2190). -) - -// TODO: the generated tries need to return size 1 for invalid runes for the -// width to be computed correctly (each byte should render width 1) - -var trie = newWidthTrie(0) - -// Lookup reports the Properties of the first rune in b and the number of bytes -// of its UTF-8 encoding. -func Lookup(b []byte) (p Properties, size int) { - v, sz := trie.lookup(b) - return Properties{elem(v), b[sz-1]}, sz -} - -// LookupString reports the Properties of the first rune in s and the number of -// bytes of its UTF-8 encoding. -func LookupString(s string) (p Properties, size int) { - v, sz := trie.lookupString(s) - return Properties{elem(v), s[sz-1]}, sz -} - -// LookupRune reports the Properties of rune r. -func LookupRune(r rune) Properties { - var buf [4]byte - n := utf8.EncodeRune(buf[:], r) - v, _ := trie.lookup(buf[:n]) - last := byte(r) - if r >= utf8.RuneSelf { - last = 0x80 + byte(r&0x3f) - } - return Properties{elem(v), last} -} - -// Properties provides access to width properties of a rune. -type Properties struct { - elem elem - last byte -} - -func (e elem) kind() Kind { - return Kind(e >> typeShift) -} - -// Kind returns the Kind of a rune as defined in Unicode TR #11. -// See http://unicode.org/reports/tr11/ for more details. -func (p Properties) Kind() Kind { - return p.elem.kind() -} - -// Folded returns the folded variant of a rune or 0 if the rune is canonical. -func (p Properties) Folded() rune { - if p.elem&tagNeedsFold != 0 { - buf := inverseData[byte(p.elem)] - buf[buf[0]] ^= p.last - r, _ := utf8.DecodeRune(buf[1 : 1+buf[0]]) - return r - } - return 0 -} - -// Narrow returns the narrow variant of a rune or 0 if the rune is already -// narrow or doesn't have a narrow variant. -func (p Properties) Narrow() rune { - if k := p.elem.kind(); byte(p.elem) != 0 && (k == EastAsianFullwidth || k == EastAsianWide || k == EastAsianAmbiguous) { - buf := inverseData[byte(p.elem)] - buf[buf[0]] ^= p.last - r, _ := utf8.DecodeRune(buf[1 : 1+buf[0]]) - return r - } - return 0 -} - -// Wide returns the wide variant of a rune or 0 if the rune is already -// wide or doesn't have a wide variant. -func (p Properties) Wide() rune { - if k := p.elem.kind(); byte(p.elem) != 0 && (k == EastAsianHalfwidth || k == EastAsianNarrow) { - buf := inverseData[byte(p.elem)] - buf[buf[0]] ^= p.last - r, _ := utf8.DecodeRune(buf[1 : 1+buf[0]]) - return r - } - return 0 -} - -// TODO for Properties: -// - Add Fullwidth/Halfwidth or Inverted methods for computing variants -// mapping. -// - Add width information (including information on non-spacing runes). - -// Transformer implements the transform.Transformer interface. -type Transformer struct { - t transform.SpanningTransformer -} - -// Reset implements the transform.Transformer interface. -func (t Transformer) Reset() { t.t.Reset() } - -// Transform implements the transform.Transformer interface. -func (t Transformer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { - return t.t.Transform(dst, src, atEOF) -} - -// Span implements the transform.SpanningTransformer interface. -func (t Transformer) Span(src []byte, atEOF bool) (n int, err error) { - return t.t.Span(src, atEOF) -} - -// Bytes returns a new byte slice with the result of applying t to b. -func (t Transformer) Bytes(b []byte) []byte { - b, _, _ = transform.Bytes(t, b) - return b -} - -// String returns a string with the result of applying t to s. -func (t Transformer) String(s string) string { - s, _, _ = transform.String(t, s) - return s -} - -var ( - // Fold is a transform that maps all runes to their canonical width. - // - // Note that the NFKC and NFKD transforms in golang.org/x/text/unicode/norm - // provide a more generic folding mechanism. - Fold Transformer = Transformer{foldTransform{}} - - // Widen is a transform that maps runes to their wide variant, if - // available. - Widen Transformer = Transformer{wideTransform{}} - - // Narrow is a transform that maps runes to their narrow variant, if - // available. - Narrow Transformer = Transformer{narrowTransform{}} -) - -// TODO: Consider the following options: -// - Treat Ambiguous runes that have a halfwidth counterpart as wide, or some -// generalized variant of this. -// - Consider a wide Won character to be the default width (or some generalized -// variant of this). -// - Filter the set of characters that gets converted (the preferred approach is -// to allow applying filters to transforms). |