71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
/*
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* Copyright (c) SAS Institute, 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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* 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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package cpio
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import (
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"fmt"
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"io"
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)
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type file_stream struct {
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stream io.ReadSeeker
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start_pos int64
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curr_pos int64
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size int64
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}
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func newFileStream(stream io.ReadSeeker, size int64) (*file_stream, error) {
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pos, err := stream.Seek(0, 1)
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if err != nil {
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return nil, err
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}
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return &file_stream{
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stream: stream,
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start_pos: pos,
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curr_pos: 0,
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size: size,
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}, nil
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}
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func (fs *file_stream) Read(p []byte) (n int, err error) {
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logger.Debugf("reading: %d, start_pos: %d, curr_pos: %d, size: %d",
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len(p), fs.start_pos, fs.curr_pos, fs.size)
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if fs.curr_pos >= fs.size {
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logger.Debugf("cur_pos: %d, size: %d", fs.curr_pos, fs.size)
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logger.Debug("EOF")
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return 0, io.EOF
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}
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pos, err := fs.stream.Seek(0, 1)
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if err != nil {
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return 0, err
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}
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if fs.start_pos+fs.curr_pos != pos {
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logger.Debugf("start_pos: %d, curr_pos: %d, pos: %d",
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fs.start_pos, fs.curr_pos, pos)
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return 0, fmt.Errorf("read out of order")
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}
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if int64(len(p)) > fs.size-fs.curr_pos {
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p = p[0 : fs.size-fs.curr_pos]
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}
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n, err = fs.stream.Read(p)
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fs.curr_pos += int64(n)
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//logger.Debugf("read %v", p)
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return
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}
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