hugo/common/hugio/hasBytesWriter.go

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// Copyright 2022 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package hugio
import (
"bytes"
)
// HasBytesWriter is a writer that will set Match to true if the given pattern
// is found in the stream.
type HasBytesWriter struct {
Match bool
Pattern []byte
i int
done bool
buff []byte
}
func (h *HasBytesWriter) Write(p []byte) (n int, err error) {
if h.done {
return len(p), nil
}
if len(h.buff) == 0 {
h.buff = make([]byte, len(h.Pattern)*2)
}
for i := range p {
h.buff[h.i] = p[i]
h.i++
if h.i == len(h.buff) {
// Shift left.
copy(h.buff, h.buff[len(h.buff)/2:])
h.i = len(h.buff) / 2
}
if bytes.Contains(h.buff, h.Pattern) {
h.Match = true
h.done = true
return len(p), nil
}
}
return len(p), nil
}