2012-12-21 05:57:03 +00:00
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package storage
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import (
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2012-12-21 06:32:21 +00:00
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"errors"
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2012-12-21 05:57:03 +00:00
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"io"
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"os"
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"pkg/util"
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)
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func (n *Needle) Append(w io.Writer) uint32 {
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header := make([]byte, 16)
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util.Uint32toBytes(header[0:4], n.Cookie)
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util.Uint64toBytes(header[4:12], n.Id)
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n.Size = uint32(len(n.Data))
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util.Uint32toBytes(header[12:16], n.Size)
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w.Write(header)
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w.Write(n.Data)
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2012-12-21 06:32:21 +00:00
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rest := 8 - ((16 + n.Size + 4) % 8)
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2012-12-21 05:57:03 +00:00
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util.Uint32toBytes(header[0:4], n.Checksum.Value())
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w.Write(header[0 : 4+rest])
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2012-12-21 05:57:03 +00:00
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return n.Size
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}
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func (n *Needle) Read(r io.Reader, size uint32, version Version) (int, error) {
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if version == Version1 {
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2012-12-21 06:32:21 +00:00
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bytes := make([]byte, 16+size+4)
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2012-12-21 05:57:03 +00:00
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ret, e := r.Read(bytes)
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n.Cookie = util.BytesToUint32(bytes[0:4])
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n.Id = util.BytesToUint64(bytes[4:12])
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n.Size = util.BytesToUint32(bytes[12:16])
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n.Data = bytes[16 : 16+size]
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checksum := util.BytesToUint32(bytes[16+size : 16+size+4])
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if checksum != NewCRC(n.Data).Value() {
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return 0, errors.New("CRC error! Data On Disk Corrupted!")
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}
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return ret, e
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2012-12-21 06:32:21 +00:00
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} else if version == Version2 {
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}
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return 0, errors.New("Unsupported Version!")
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}
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func ReadNeedle(r *os.File, version Version) (n *Needle, bytesTillNextFile uint32) {
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n = new(Needle)
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if version == Version1 {
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bytes := make([]byte, 16)
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count, e := r.Read(bytes)
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if count <= 0 || e != nil {
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return nil, 0
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}
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n.Cookie = util.BytesToUint32(bytes[0:4])
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n.Id = util.BytesToUint64(bytes[4:12])
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n.Size = util.BytesToUint32(bytes[12:16])
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rest := 8 - ((n.Size + 16 + 4) % 8)
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bytesTillNextFile = n.Size + 4 + rest
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} else if version == Version2 {
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}
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2012-12-21 06:32:21 +00:00
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return
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2012-12-21 05:57:03 +00:00
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}
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