示例#1
0
func crcAppend(w WriteAheadLogger, entries [][]byte) (uint64, uint64, error) {
	crc := make([]uint32, 0, len(entries))
	for _, d := range entries {
		crc = append(crc, crc32.ChecksumIEEE(d))
	}
	return w.AppendBytes(entries, crc)
}
示例#2
0
func (c *crc32Field) check(curOffset int, buf []byte) error {
	crc := crc32.ChecksumIEEE(buf[c.startOffset+4 : curOffset])

	if crc != binary.BigEndian.Uint32(buf[c.startOffset:]) {
		return PacketDecodingError{"CRC didn't match"}
	}

	return nil
}
示例#3
0
文件: superblock.go 项目: allmad/madq
func (s *Superblock) findByName(name InodeName, r io.ReaderAt) (int64, error) {
	addr, ok := s.inodeAddr[name]
	if ok {
		return addr, nil
	}
	hash := crc32.ChecksumIEEE(name[:])
	idx := int(hash) % len(s.IndirectAddr)
	for tryTime := 0; tryTime < 8; tryTime++ {
		offset, err := s.findAtBlock(name, r, s.IndirectAddr[idx])
		if err == nil {
			return offset, nil
		}
		if logex.Equal(err, io.EOF) {
			idx++
			continue
		}
		return 0, logex.Trace(err)
	}
	return 0, ErrNotFound.Trace()
}
示例#4
0
func (c *crc32Field) run(curOffset int, buf []byte) error {
	crc := crc32.ChecksumIEEE(buf[c.startOffset+4 : curOffset])
	binary.BigEndian.PutUint32(buf[c.startOffset:], crc)
	return nil
}
示例#5
0
// readHeader reads the GZIP header according to section 2.3.1.
// This method does not set z.err.
func (z *Reader) readHeader() (hdr Header, err error) {
	if _, err = io.ReadFull(z.r, z.buf[:10]); err != nil {
		// RFC 1952, section 2.2, says the following:
		//	A gzip file consists of a series of "members" (compressed data sets).
		//
		// Other than this, the specification does not clarify whether a
		// "series" is defined as "one or more" or "zero or more". To err on the
		// side of caution, Go interprets this to mean "zero or more".
		// Thus, it is okay to return io.EOF here.
		return hdr, err
	}
	if z.buf[0] != gzipID1 || z.buf[1] != gzipID2 || z.buf[2] != gzipDeflate {
		return hdr, ErrHeader
	}
	flg := z.buf[3]
	hdr.ModTime = time.Unix(int64(le.Uint32(z.buf[4:8])), 0)
	// z.buf[8] is XFL and is currently ignored.
	hdr.OS = z.buf[9]
	z.digest = crc32.ChecksumIEEE(z.buf[:10])

	if flg&flagExtra != 0 {
		if _, err = io.ReadFull(z.r, z.buf[:2]); err != nil {
			return hdr, noEOF(err)
		}
		z.digest = crc32.Update(z.digest, crc32.IEEETable, z.buf[:2])
		data := make([]byte, le.Uint16(z.buf[:2]))
		if _, err = io.ReadFull(z.r, data); err != nil {
			return hdr, noEOF(err)
		}
		z.digest = crc32.Update(z.digest, crc32.IEEETable, data)
		hdr.Extra = data
	}

	var s string
	if flg&flagName != 0 {
		if s, err = z.readString(); err != nil {
			return hdr, err
		}
		hdr.Name = s
	}

	if flg&flagComment != 0 {
		if s, err = z.readString(); err != nil {
			return hdr, err
		}
		hdr.Comment = s
	}

	if flg&flagHdrCrc != 0 {
		if _, err = io.ReadFull(z.r, z.buf[:2]); err != nil {
			return hdr, noEOF(err)
		}
		digest := le.Uint16(z.buf[:2])
		if digest != uint16(z.digest) {
			return hdr, ErrHeader
		}
	}

	z.digest = 0
	if z.decompressor == nil {
		z.decompressor = flate.NewReader(z.r)
	} else {
		z.decompressor.(flate.Resetter).Reset(z.r, nil)
	}
	return hdr, nil
}