github.com/go-xe2/third@v1.0.3/golang.org/x/text/unicode/norm/example_iter_test.go (about)

     1  // Copyright 2012 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 norm_test
     6  
     7  import (
     8  	"bytes"
     9  	"fmt"
    10  	"unicode/utf8"
    11  
    12  	"github.com/go-xe2/third/golang.org/x/text/unicode/norm"
    13  )
    14  
    15  // EqualSimple uses a norm.Iter to compare two non-normalized
    16  // strings for equivalence.
    17  func EqualSimple(a, b string) bool {
    18  	var ia, ib norm.Iter
    19  	ia.InitString(norm.NFKD, a)
    20  	ib.InitString(norm.NFKD, b)
    21  	for !ia.Done() && !ib.Done() {
    22  		if !bytes.Equal(ia.Next(), ib.Next()) {
    23  			return false
    24  		}
    25  	}
    26  	return ia.Done() && ib.Done()
    27  }
    28  
    29  // FindPrefix finds the longest common prefix of ASCII characters
    30  // of a and b.
    31  func FindPrefix(a, b string) int {
    32  	i := 0
    33  	for ; i < len(a) && i < len(b) && a[i] < utf8.RuneSelf && a[i] == b[i]; i++ {
    34  	}
    35  	return i
    36  }
    37  
    38  // EqualOpt is like EqualSimple, but optimizes the special
    39  // case for ASCII characters.
    40  func EqualOpt(a, b string) bool {
    41  	n := FindPrefix(a, b)
    42  	a, b = a[n:], b[n:]
    43  	var ia, ib norm.Iter
    44  	ia.InitString(norm.NFKD, a)
    45  	ib.InitString(norm.NFKD, b)
    46  	for !ia.Done() && !ib.Done() {
    47  		if !bytes.Equal(ia.Next(), ib.Next()) {
    48  			return false
    49  		}
    50  		if n := int64(FindPrefix(a[ia.Pos():], b[ib.Pos():])); n != 0 {
    51  			ia.Seek(n, 1)
    52  			ib.Seek(n, 1)
    53  		}
    54  	}
    55  	return ia.Done() && ib.Done()
    56  }
    57  
    58  var compareTests = []struct{ a, b string }{
    59  	{"aaa", "aaa"},
    60  	{"aaa", "aab"},
    61  	{"a\u0300a", "\u00E0a"},
    62  	{"a\u0300\u0320b", "a\u0320\u0300b"},
    63  	{"\u1E0A\u0323", "\x44\u0323\u0307"},
    64  	// A character that decomposes into multiple segments
    65  	// spans several iterations.
    66  	{"\u3304", "\u30A4\u30CB\u30F3\u30AF\u3099"},
    67  }
    68  
    69  func ExampleIter() {
    70  	for i, t := range compareTests {
    71  		r0 := EqualSimple(t.a, t.b)
    72  		r1 := EqualOpt(t.a, t.b)
    73  		fmt.Printf("%d: %v %v\n", i, r0, r1)
    74  	}
    75  	// Output:
    76  	// 0: true true
    77  	// 1: false false
    78  	// 2: true true
    79  	// 3: true true
    80  	// 4: true true
    81  	// 5: true true
    82  }