vendorify
diff --git a/go/vendor/golang.org/x/text/width/width.go b/go/vendor/golang.org/x/text/width/width.go
new file mode 100644
index 0000000..f1639ca
--- /dev/null
+++ b/go/vendor/golang.org/x/text/width/width.go
@@ -0,0 +1,206 @@
+// 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).