github.com/icodeface/tls@v0.0.0-20230910023335-34df9250cd12/internal/x/text/unicode/norm/example_iter_test.go (about)

     1  // Code generated by running "go run gen.go -core" in golang.org/x/text. DO NOT EDIT.
     2  
     3  // Copyright 2012 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package norm_test
     8  
     9  import (
    10  	"bytes"
    11  	"fmt"
    12  	"unicode/utf8"
    13  
    14  	"github.com/icodeface/tls/internal/x/text/unicode/norm"
    15  )
    16  
    17  // EqualSimple uses a norm.Iter to compare two non-normalized
    18  // strings for equivalence.
    19  func EqualSimple(a, b string) bool {
    20  	var ia, ib norm.Iter
    21  	ia.InitString(norm.NFKD, a)
    22  	ib.InitString(norm.NFKD, b)
    23  	for !ia.Done() && !ib.Done() {
    24  		if !bytes.Equal(ia.Next(), ib.Next()) {
    25  			return false
    26  		}
    27  	}
    28  	return ia.Done() && ib.Done()
    29  }
    30  
    31  // FindPrefix finds the longest common prefix of ASCII characters
    32  // of a and b.
    33  func FindPrefix(a, b string) int {
    34  	i := 0
    35  	for ; i < len(a) && i < len(b) && a[i] < utf8.RuneSelf && a[i] == b[i]; i++ {
    36  	}
    37  	return i
    38  }
    39  
    40  // EqualOpt is like EqualSimple, but optimizes the special
    41  // case for ASCII characters.
    42  func EqualOpt(a, b string) bool {
    43  	n := FindPrefix(a, b)
    44  	a, b = a[n:], b[n:]
    45  	var ia, ib norm.Iter
    46  	ia.InitString(norm.NFKD, a)
    47  	ib.InitString(norm.NFKD, b)
    48  	for !ia.Done() && !ib.Done() {
    49  		if !bytes.Equal(ia.Next(), ib.Next()) {
    50  			return false
    51  		}
    52  		if n := int64(FindPrefix(a[ia.Pos():], b[ib.Pos():])); n != 0 {
    53  			ia.Seek(n, 1)
    54  			ib.Seek(n, 1)
    55  		}
    56  	}
    57  	return ia.Done() && ib.Done()
    58  }
    59  
    60  var compareTests = []struct{ a, b string }{
    61  	{"aaa", "aaa"},
    62  	{"aaa", "aab"},
    63  	{"a\u0300a", "\u00E0a"},
    64  	{"a\u0300\u0320b", "a\u0320\u0300b"},
    65  	{"\u1E0A\u0323", "\x44\u0323\u0307"},
    66  	// A character that decomposes into multiple segments
    67  	// spans several iterations.
    68  	{"\u3304", "\u30A4\u30CB\u30F3\u30AF\u3099"},
    69  }
    70  
    71  func ExampleIter() {
    72  	for i, t := range compareTests {
    73  		r0 := EqualSimple(t.a, t.b)
    74  		r1 := EqualOpt(t.a, t.b)
    75  		fmt.Printf("%d: %v %v\n", i, r0, r1)
    76  	}
    77  	// Output:
    78  	// 0: true true
    79  	// 1: false false
    80  	// 2: true true
    81  	// 3: true true
    82  	// 4: true true
    83  	// 5: true true
    84  }