/
gzip_filter.go
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/
gzip_filter.go
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// Copyright (c) 2019 The BFE Authors.
//
// 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 mod_compress
import (
"bytes"
"compress/gzip"
"io"
)
type GzipFilter struct {
source io.ReadCloser
writer *gzip.Writer
buffer bytes.Buffer
flushSize int64
closed bool
}
func NewGzipFilter(source io.ReadCloser, level int, size int) (b *GzipFilter, err error) {
b = new(GzipFilter)
b.writer, err = gzip.NewWriterLevel(&b.buffer, level)
if err != nil {
return nil, err
}
b.source = source
b.flushSize = int64(size)
return b, nil
}
func (b *GzipFilter) Read(p []byte) (n int, err error) {
c, err := io.CopyN(b.writer, b.source, b.flushSize)
if err != nil && err != io.EOF {
return 0, err
}
if c != 0 {
if err := b.writer.Flush(); err != nil {
return 0, err
}
} else if !b.closed {
b.closed = true
if err := b.writer.Close(); err != nil {
return 0, err
}
}
return b.buffer.Read(p)
}
func (b *GzipFilter) Close() error {
if err := b.source.Close(); err != nil {
return err
}
return nil
}