runenames.go

Documentation: golang.org/x/text/unicode/runenames

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:generate go run gen.go
     6  
     7  // Package runenames provides rune names from the Unicode Character Database.
     8  // For example, the name for '\u0100' is "LATIN CAPITAL LETTER A WITH MACRON".
     9  //
    10  // See https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
    11  package runenames
    12  
    13  import (
    14  	"sort"
    15  )
    16  
    17  // Name returns the name for r.
    18  func Name(r rune) string {
    19  	i := sort.Search(len(entries), func(j int) bool {
    20  		return entries[j].startRune() > r
    21  	})
    22  	if i == 0 {
    23  		return ""
    24  	}
    25  	e := entries[i-1]
    26  
    27  	offset := int(r - e.startRune())
    28  	if offset >= e.numRunes() {
    29  		return ""
    30  	}
    31  
    32  	if e.direct() {
    33  		o := e.index()
    34  		n := e.len()
    35  		return directData[o : o+n]
    36  	}
    37  
    38  	start := int(index[e.index()+offset])
    39  	end := int(index[e.index()+offset+1])
    40  	base1 := e.base() << 16
    41  	base2 := base1
    42  	if start > end {
    43  		base2 += 1 << 16
    44  	}
    45  	return singleData[start+base1 : end+base2]
    46  }
    47  
    48  func (e entry) len() int { return e.base() }
    49
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