func()

in flexflate/gen.go [48:120]

• 68 lines of code
• 16 McCabe index (conditional complexity)

func (h *huffmanDecoder) init(bits []int) bool {
	// Count number of codes of each length,
	// compute min and max length.
	var count [maxCodeLen]int
	var min, max int
	for _, n := range bits {
		if n == 0 {
			continue
		}
		if min == 0 || n < min {
			min = n
		}
		if n > max {
			max = n
		}
		count[n]++
	}
	if max == 0 {
		return false
	}

	h.min = min
	var linkBits uint
	var numLinks int
	if max > huffmanChunkBits {
		linkBits = uint(max) - huffmanChunkBits
		numLinks = 1 << linkBits
		h.linkMask = uint32(numLinks - 1)
	}
	code := 0
	var nextcode [maxCodeLen]int
	for i := min; i <= max; i++ {
		if i == huffmanChunkBits+1 {
			// create link tables
			link := code >> 1
			h.links = make([][]uint32, huffmanNumChunks-link)
			for j := uint(link); j < huffmanNumChunks; j++ {
				reverse := int(reverseByte[j>>8]) | int(reverseByte[j&0xff])<<8
				reverse >>= uint(16 - huffmanChunkBits)
				off := j - uint(link)
				h.chunks[reverse] = uint32(off<<huffmanValueShift + uint(i))
				h.links[off] = make([]uint32, 1<<linkBits)
			}
		}
		n := count[i]
		nextcode[i] = code
		code += n
		code <<= 1
	}

	for i, n := range bits {
		if n == 0 {
			continue
		}
		code := nextcode[n]
		nextcode[n]++
		chunk := uint32(i<<huffmanValueShift | n)
		reverse := int(reverseByte[code>>8]) | int(reverseByte[code&0xff])<<8
		reverse >>= uint(16 - n)
		if n <= huffmanChunkBits {
			for off := reverse; off < huffmanNumChunks; off += 1 << uint(n) {
				h.chunks[off] = chunk
			}
		} else {
			linktab := h.links[h.chunks[reverse&(huffmanNumChunks-1)]>>huffmanValueShift]
			reverse >>= huffmanChunkBits
			for off := reverse; off < numLinks; off += 1 << uint(n-huffmanChunkBits) {
				linktab[off] = chunk
			}
		}
	}
	return true
}