122 lines
2.8 KiB
Go
122 lines
2.8 KiB
Go
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/**
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* Copyright 2014 Paul Querna
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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/* Portions of this file are on Go stdlib's encoding/json/fold.go */
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package v1
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import (
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"unicode/utf8"
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)
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const (
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caseMask = ^byte(0x20) // Mask to ignore case in ASCII.
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kelvin = '\u212a'
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smallLongEss = '\u017f'
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)
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// equalFoldRight is a specialization of bytes.EqualFold when s is
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// known to be all ASCII (including punctuation), but contains an 's',
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// 'S', 'k', or 'K', requiring a Unicode fold on the bytes in t.
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// See comments on foldFunc.
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func EqualFoldRight(s, t []byte) bool {
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for _, sb := range s {
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if len(t) == 0 {
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return false
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}
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tb := t[0]
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if tb < utf8.RuneSelf {
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if sb != tb {
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sbUpper := sb & caseMask
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if 'A' <= sbUpper && sbUpper <= 'Z' {
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if sbUpper != tb&caseMask {
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return false
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}
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} else {
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return false
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}
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}
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t = t[1:]
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continue
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}
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// sb is ASCII and t is not. t must be either kelvin
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// sign or long s; sb must be s, S, k, or K.
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tr, size := utf8.DecodeRune(t)
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switch sb {
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case 's', 'S':
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if tr != smallLongEss {
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return false
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}
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case 'k', 'K':
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if tr != kelvin {
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return false
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}
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default:
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return false
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}
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t = t[size:]
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}
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if len(t) > 0 {
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return false
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}
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return true
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}
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// asciiEqualFold is a specialization of bytes.EqualFold for use when
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// s is all ASCII (but may contain non-letters) and contains no
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// special-folding letters.
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// See comments on foldFunc.
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func AsciiEqualFold(s, t []byte) bool {
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if len(s) != len(t) {
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return false
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}
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for i, sb := range s {
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tb := t[i]
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if sb == tb {
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continue
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}
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if ('a' <= sb && sb <= 'z') || ('A' <= sb && sb <= 'Z') {
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if sb&caseMask != tb&caseMask {
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return false
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}
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} else {
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return false
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}
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}
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return true
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}
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// simpleLetterEqualFold is a specialization of bytes.EqualFold for
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// use when s is all ASCII letters (no underscores, etc) and also
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// doesn't contain 'k', 'K', 's', or 'S'.
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// See comments on foldFunc.
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func SimpleLetterEqualFold(s, t []byte) bool {
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if len(s) != len(t) {
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return false
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}
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for i, b := range s {
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if b&caseMask != t[i]&caseMask {
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return false
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}
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}
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return true
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}
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