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// Copyright 2012 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.
package norm_test
import (
"bytes"
"exp/norm"
"fmt"
"unicode/utf8"
)
// EqualSimple uses a norm.Iter to compare two non-normalized
// strings for equivalence.
func EqualSimple(a, b string) bool {
var ia, ib norm.Iter
ia.InitString(norm.NFKD, a)
ib.InitString(norm.NFKD, b)
for !ia.Done() && !ib.Done() {
if !bytes.Equal(ia.Next(), ib.Next()) {
return false
}
}
return ia.Done() && ib.Done()
}
// FindPrefix finds the longest common prefix of ASCII characters
// of a and b.
func FindPrefix(a, b string) int {
i := 0
for ; i < len(a) && i < len(b) && a[i] < utf8.RuneSelf && a[i] == b[i]; i++ {
}
return i
}
// EqualOpt is like EqualSimple, but optimizes the special
// case for ASCII characters.
func EqualOpt(a, b string) bool {
n := FindPrefix(a, b)
a, b = a[n:], b[n:]
var ia, ib norm.Iter
ia.InitString(norm.NFKD, a)
ib.InitString(norm.NFKD, b)
for !ia.Done() && !ib.Done() {
if !bytes.Equal(ia.Next(), ib.Next()) {
return false
}
if n := int64(FindPrefix(a[ia.Pos():], b[ib.Pos():])); n != 0 {
ia.Seek(n, 1)
ib.Seek(n, 1)
}
}
return ia.Done() && ib.Done()
}
var compareTests = []struct{ a, b string }{
{"aaa", "aaa"},
{"aaa", "aab"},
{"a\u0300a", "\u00E0a"},
{"a\u0300\u0320b", "a\u0320\u0300b"},
{"\u1E0A\u0323", "\x44\u0323\u0307"},
// A character that decomposes into multiple segments
// spans several iterations.
{"\u3304", "\u30A4\u30CB\u30F3\u30AF\u3099"},
}
func ExampleIter() {
for i, t := range compareTests {
r0 := EqualSimple(t.a, t.b)
r1 := EqualOpt(t.a, t.b)
fmt.Printf("%d: %v %v\n", i, r0, r1)
}
// Output:
// 0: true true
// 1: false false
// 2: true true
// 3: true true
// 4: true true
// 5: true true
}
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