84 lines
1.9 KiB
Go
84 lines
1.9 KiB
Go
// Copyright 2021 PingCAP, Inc.
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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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// See the License for the specific language governing permissions and
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// limitations under the License.
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package charset
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import (
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"bytes"
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go_unicode "unicode"
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"golang.org/x/text/encoding"
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)
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// EncodingASCIIImpl is the instance of encodingASCII
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var EncodingASCIIImpl = &encodingASCII{encodingBase{enc: encoding.Nop}}
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func init() {
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EncodingASCIIImpl.self = EncodingASCIIImpl
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}
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// encodingASCII is the ASCII encoding.
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type encodingASCII struct {
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encodingBase
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}
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// Name implements Encoding interface.
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func (e *encodingASCII) Name() string {
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return CharsetASCII
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}
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// Tp implements Encoding interface.
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func (e *encodingASCII) Tp() EncodingTp {
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return EncodingTpASCII
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}
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// Peek implements Encoding interface.
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func (e *encodingASCII) Peek(src []byte) []byte {
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if len(src) == 0 {
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return src
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}
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return src[:1]
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}
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// IsValid implements Encoding interface.
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func (e *encodingASCII) IsValid(src []byte) bool {
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srcLen := len(src)
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for i := 0; i < srcLen; i++ {
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if src[i] > go_unicode.MaxASCII {
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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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func (e *encodingASCII) Transform(dest *bytes.Buffer, src []byte, op Op) ([]byte, error) {
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if e.IsValid(src) {
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return src, nil
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}
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return e.encodingBase.Transform(dest, src, op)
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}
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func (e *encodingASCII) Foreach(src []byte, op Op, fn func(from, to []byte, ok bool) bool) {
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for i, w := 0, 0; i < len(src); i += w {
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w = 1
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ok := true
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if src[i] > go_unicode.MaxASCII {
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w = len(EncodingUTF8Impl.Peek(src[i:]))
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ok = false
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}
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if !fn(src[i:i+w], src[i:i+w], ok) {
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return
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}
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}
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}
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