You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: huffman.go
    path of file: ./repos/gotosocial/vendor/golang.org/x/image/vp8l
    
    the code of the file until where you have to start completion: // Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package vp8l

import (
	"io"
)

// reverseBits reverses the bits in a byte.
var reverseBits = [256]uint8{
	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 
    
func (h *hTree) insert(symbol uint32, code uint32, codeLength uint32) error {
	if symbol > 0xffff || codeLength > 0xfe {
		return errInvalidHuffmanTree
	}
	baseCode := uint32(0)
	if codeLength > lutSize {
		baseCode = uint32(reverseBits[(code>>(codeLength-lutSize))&0xff]) >> (8 - lutSize)
	} else {
		baseCode = uint32(reverseBits[code&0xff]) >> (8 - codeLength)
		for i := 0; i < 1<<(lutSize-codeLength); i++ {
			h.lut[baseCode|uint32(i)<<codeLength] = symbol<<8 | (codeLength + 1)
		}
	}

	n := uint32(0)
	for jump := lutSize; codeLength > 0; {
		codeLength--
		if int(n) > len(h.nodes) {
			return errInvalidHuffmanTree
		}
		switch h.nodes[n].children {
		case leafNode:
			return errInvalidHuffmanTree
		case 0:
			if len(h.nodes) == cap(h.nodes) {
				return errInvalidHuffmanTree
			}
			// Create two empty child nodes.
			h.nodes[n].children = int32(len(h.nodes))
			h.nodes = h.nodes[:len(h.nodes)+2]
		}
		n = uint32(h.nodes[n].children) + 1&(code>>codeLength)
		jump--
		if jump == 0 && h.lut[baseCode] == 0 {
			h.lut[baseCode] = n << 8
		}
	}

	switch h.nodes[n].children {
	case leafNode:
		// No-op.
	case 0:
		// Turn the uninitialized node into a leaf.
		h.nodes[n].children = leafNode
	default:
		return errInvalidHuffmanTree
	}
	h.nodes[n].symbol = symbol
	return nil
}