76 lines
1.4 KiB
Go
76 lines
1.4 KiB
Go
package main
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import (
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"bytes"
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"encoding/binary"
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"hash"
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"io"
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"log"
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)
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func errorExit(err error) {
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if err != nil {
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log.Fatal("ERROR:", err)
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}
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}
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func vLog(f string, v ...interface{}) {
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if opts.Verbose {
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log.Printf(f, v...)
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}
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}
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func position(s io.Seeker) (pos int64, err error) {
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return s.Seek(0, io.SeekCurrent)
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}
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func checkPosition(s io.Seeker) int64 {
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pos, err := position(s)
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errorExit(err)
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return pos
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}
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func checkOffset(s io.Seeker, offset int64) {
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pos := checkPosition(s)
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if pos != offset {
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vLog("READ: position: %x expected: %x", pos, offset)
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}
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}
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type byteProvider interface {
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Next(n int) []byte
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}
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func readNextOffset(s io.Seeker, p byteProvider) (int64, bool) {
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rawOffset := binary.LittleEndian.Uint32(p.Next(4))
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if rawOffset != 0xffffffff {
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offset := int64(rawOffset) << 8
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checkOffset(s, offset)
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return offset, true
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}
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return 0, false
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}
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func setNextOffset(s io.Seeker, p byteProvider) bool {
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offset, ok := readNextOffset(s, p)
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if ok {
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_, err := s.Seek(offset, io.SeekStart)
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errorExit(err)
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}
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return ok
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}
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func blockTransfer(r io.Reader, w io.Writer, buffer []byte) int {
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_, err := io.ReadFull(r, buffer)
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errorExit(err)
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wrote, err := w.Write(buffer)
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errorExit(err)
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return wrote
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}
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func blockTransferWithHash(r io.Reader, w io.Writer, buffer []byte, hash hash.Hash) int {
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wrote := blockTransfer(r, w, buffer)
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io.Copy(hash, bytes.NewBuffer(buffer))
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return wrote
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}
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