Method packBlock

bitmap/codec.go:79–124

()

}

func (e *Encoder) packBlock() {
	if len(e.uids) == 0 {
		return
	}

	// Allocate blocks manually.
	b := e.Alloc.AllocateAligned(blockSize)
	block := (*UidBlock)(unsafe.Pointer(&b[0]))

	block.Base = e.uids[0]
	block.NumUids = uint32(len(e.uids))

	// block := &UidBlock{Base: e.uids[0], NumUids: uint32(len(e.uids))}
	last := e.uids[0]
	e.uids = e.uids[1:]

	e.buf.Reset()
	buf := make([]byte, 17)
	tmpUids := make([]uint32, 4)
	for {
		for i := 0; i < 4; i++ {
			if i >= len(e.uids) {
				// Padding with '0' because Encode4 encodes only in batch of 4.
				tmpUids[i] = 0
			} else {
				tmpUids[i] = uint32(e.uids[i] - last)
				last = e.uids[i]
			}
		}

		data := groupvarint.Encode4(buf, tmpUids)
		Check2(e.buf.Write(data))

		// e.uids has ended and we have padded tmpUids with 0s
		if len(e.uids) <= 4 {
			e.uids = e.uids[:0]
			break
		}
		e.uids = e.uids[4:]
	}

	sz := len(e.buf.Bytes())
	block.Deltas = e.Alloc.Allocate(sz)
	AssertTrue(sz == copy(block.Deltas, e.buf.Bytes()))
	e.pack.Blocks = append(e.pack.Blocks, block)
}

var tagEncoder string = "enc"