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byteBuffer.go
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byteBuffer.go
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// Copyright 2015-2018 trivago N.V.
//
// 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 awss3
import (
"crypto/sha1"
"encoding/hex"
"fmt"
"io"
)
// s3ByteBuffer is a byte buffer used for s3 target objects
type s3ByteBuffer struct {
bytes []byte
position int64
}
func newS3ByteBuffer() *s3ByteBuffer {
return &s3ByteBuffer{
bytes: make([]byte, 0),
position: int64(0),
}
}
func (buf *s3ByteBuffer) Bytes() ([]byte, error) {
return buf.bytes, nil
}
func (buf *s3ByteBuffer) CloseAndDelete() error {
buf.bytes = make([]byte, 0)
buf.position = 0
return nil
}
func (buf *s3ByteBuffer) Read(p []byte) (n int, err error) {
n = copy(p, buf.bytes[buf.position:])
buf.position += int64(n)
if buf.position == int64(len(buf.bytes)) {
return n, io.EOF
}
return n, nil
}
func (buf *s3ByteBuffer) Write(p []byte) (n int, err error) {
buf.bytes = append(buf.bytes[:buf.position], p...)
buf.position += int64(len(p))
return len(p), nil
}
func (buf *s3ByteBuffer) Seek(offset int64, whence int) (int64, error) {
var position int64
switch whence {
case 0: // io.SeekStart
position = offset
case 1: // io.SeekCurrent
position = buf.position + offset
case 2: // io.SeekEnd
position = int64(len(buf.bytes)) + offset
}
if position < 0 {
return 0, fmt.Errorf("S3Buffer bad seek result %d", position)
}
buf.position = position
return position, nil
}
func (buf *s3ByteBuffer) Size() (int, error) {
return len(buf.bytes), nil
}
func (buf *s3ByteBuffer) Sha1() (string, error) {
hash := sha1.Sum(buf.bytes)
return hex.EncodeToString(hash[:]), nil
}