rangetable.go

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

     1  // Copyright 2015 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  // Package rangetable provides utilities for creating and inspecting
     6  // unicode.RangeTables.
     7  package rangetable
     8  
     9  import (
    10  	"sort"
    11  	"unicode"
    12  )
    13  
    14  // New creates a RangeTable from the given runes, which may contain duplicates.
    15  func New(r ...rune) *unicode.RangeTable {
    16  	if len(r) == 0 {
    17  		return &unicode.RangeTable{}
    18  	}
    19  
    20  	sort.Sort(byRune(r))
    21  
    22  	// Remove duplicates.
    23  	k := 1
    24  	for i := 1; i < len(r); i++ {
    25  		if r[k-1] != r[i] {
    26  			r[k] = r[i]
    27  			k++
    28  		}
    29  	}
    30  
    31  	var rt unicode.RangeTable
    32  	for _, r := range r[:k] {
    33  		if r <= 0xFFFF {
    34  			rt.R16 = append(rt.R16, unicode.Range16{Lo: uint16(r), Hi: uint16(r), Stride: 1})
    35  		} else {
    36  			rt.R32 = append(rt.R32, unicode.Range32{Lo: uint32(r), Hi: uint32(r), Stride: 1})
    37  		}
    38  	}
    39  
    40  	// Optimize RangeTable.
    41  	return Merge(&rt)
    42  }
    43  
    44  type byRune []rune
    45  
    46  func (r byRune) Len() int           { return len(r) }
    47  func (r byRune) Swap(i, j int)      { r[i], r[j] = r[j], r[i] }
    48  func (r byRune) Less(i, j int) bool { return r[i] < r[j] }
    49  
    50  // Visit visits all runes in the given RangeTable in order, calling fn for each.
    51  func Visit(rt *unicode.RangeTable, fn func(rune)) {
    52  	for _, r16 := range rt.R16 {
    53  		for r := rune(r16.Lo); r <= rune(r16.Hi); r += rune(r16.Stride) {
    54  			fn(r)
    55  		}
    56  	}
    57  	for _, r32 := range rt.R32 {
    58  		for r := rune(r32.Lo); r <= rune(r32.Hi); r += rune(r32.Stride) {
    59  			fn(r)
    60  		}
    61  	}
    62  }
    63  
    64  // Assigned returns a RangeTable with all assigned code points for a given
    65  // Unicode version. This includes graphic, format, control, and private-use
    66  // characters. It returns nil if the data for the given version is not
    67  // available.
    68  func Assigned(version string) *unicode.RangeTable {
    69  	return assigned[version]
    70  }
    71
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