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func ReadUvarint(r io.ByteReader) (uint64, error) {
	// Modified from the go standard library. Copyright the Go Authors and
	// released under the BSD License.
	var x uint64
	var s uint
	for i := 0; ; i++ {
		b, err := r.ReadByte()
		if err != nil {
			if err == io.EOF && i != 0 {
				// "eof" will look like a success.
				// If we've read part of a value, this is not a
				// success.
				err = io.ErrUnexpectedEOF
			}
			return 0, err
		}
		if (i == 8 && b >= 0x80) || i >= MaxLenUvarint63 {
			// this is the 9th and last byte we're willing to read, but it
			// signals there's more (1 in MSB).
			// or this is the >= 10th byte, and for some reason we're still here.
			return 0, ErrOverflow
		}
		if b < 0x80 {
			if b == 0 && s > 0 {
				return 0, ErrNotMinimal
			}
			return x | uint64(b)<<s, nil
		}
		x |= uint64(b&0x7f) << s
		s += 7
	}
}

func ReadUvarint(r io.ByteReader) (uint64, error) {
	// Modified from the go standard library. Copyright the Go Authors and
	// released under the BSD License.
	var x uint64
	var s uint
	for s = 0; ; s+=7 {
		b, err := r.ReadByte()
		if err != nil {
			if err == io.EOF && i != 0 {
				// "eof" will look like a success.
				// If we've read part of a value, this is not a
				// success.
				err = io.ErrUnexpectedEOF
			}
			return 0, err
		}
		if (s == 56 && b >= 0x80) || s >= (7 * MaxLenUvarint63) {
			// this is the 9th and last byte we're willing to read, but it
			// signals there's more (1 in MSB).
			// or this is the >= 10th byte, and for some reason we're still here.
			return 0, ErrOverflow
		}
                 if b < 0x80 {
			if b == 0 && s > 0 {
				return 0, ErrNotMinimal
			}
			return x | uint64(b)<<s, nil
		}
		x |= uint64(b&0x7f) << s
		s += 7
	}
}