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: decompress_generic.go
    path of file: ./repos/scan4all/vendor/github.com/klauspost/compress/huff0
    
    the code of the file until where you have to start completion: //go:build !amd64 || appengine || !gc || noasm
// +build !amd64 appengine !gc noasm

// This file contains a generic implementation of Decoder.Decompress4X.
package huff0

import (
	"errors"
	"fmt"
)

// Decompress4X will decompress a 4X encoded stream.
// The length of the supplied input must match the end of a block exactly.
// The *capacity* of the dst slice must match the destination size of
// the uncompressed data exactly.
func (d *Decoder) Decompress4X(dst, src []byte) ([]byte, error) {
	if len(d.dt.single) == 0 {
		return nil, errors.New("no table loaded")
	}
	if len(src) < 6+(4*1) {
		return nil, errors.New("input too small")
	}
	if use8BitTables && d.actualTableLog <= 8 {
		return d.decompress4X8bit(dst, src)
	}

	var br [4]bitReaderShifted
	// Decode "jump table"
	start := 6
	for i := 0; i < 3; i++ {
		length := int(src[i*2]) | (int(src[i*2+1]) << 8)
		if start+length >= len(src) {
			return nil, errors.New("truncated input (or invalid offset)")
		}
		err := br[i].init(src[start : start+length])
		if err != nil {
			return nil, err
		}
		start += length
	}
	err := br[3].init(src[start:])
	if err != nil {
		return nil, err
	}

	// destination, offset to match first output
	dstSize := cap(dst)
	dst = dst[:dstSize]
	out := dst
	dstEvery := (dstSize + 3) / 4

	const tlSize = 1 << tableLogMax
	const tlMask = tlSize - 1
	single := d.dt.single[:tlSize]

	// Use temp table to avoid bound checks/append penalty.
	buf := d.buffer()
	var off uint8
	var decoded int

	// Decode 2 values from each decoder/loop.
	const bufoff = 256
	for {
		if br[0].off < 4 || br[1].off < 4 || br[2].off < 4 || br[3].off < 4 {
			break
		}

		{
			const stream = 0
			const stream2 = 1
			br[stream].fillFast()
			br[stream2].fillFast()

			val := br[stream].peekBitsFast(d.actualTableLog)
			val2 := br[stream2].peekBitsFast(d.actualTableLog)
			v := single[val&tlMask]
			v2 := single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off] = uint8(v.entry >> 8)
			buf[stream2][off] = uint8(v2.entry >> 8)

			val = br[stream].peekBitsFast(d.actualTableLog)
			val2 = br[stream2].peekBitsFast(d.actualTableLog)
			v = single[val&tlMask]
			v2 = single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off+1] = uint8(v.entry >> 8)
			buf[stream2][off+1] = uint8(v2.entry >> 8)
		}

		{
			const stream = 2
			const stream2 = 3
			br[stream].fillFast()
			br[stream2].fillFast()

			val := br[stream].peekBitsFast(d.actualTableLog)
			val2 := br[stream2].peekBitsFast(d.actualTableLog)
			v := single[val&tlMask]
			v2 := single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off] = uint8(v.entry >> 8)
			buf[stream2][off] = uint8(v2.entry >> 8)

			val = br[stream].peekBitsFast(d.actualTableLog)
			val2 = br[stream2].peekBitsFast(d.actualTableLog)
			v = single[val&tlMask]
			v2 = single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off+1] = uint8(v.entry >> 8)
			buf[stream2][off+1] = uint8(v2.entry >> 8)
		}

		off += 2

		if off == 0 {
			if bufoff > dstEvery {
				d.bufs.Put(buf)
				return nil, errors.New("corruption detected: stream overrun 1")
			}
			// There must at least be 3 buffers left.
			if len(out)-bufoff < dstEvery*3 {
				d.bufs.Put(buf)
				return nil, errors.New("corruption detected: stream overrun 2")
			}
			//copy(out, buf[0][:])
			//copy(out[dstEvery:], buf[1][:])
			//copy(out[dstEvery*2:], buf[2][:])
			//copy(out[dstEvery*3:], buf[3][:])
			*(*[bufoff]byte)(out) = buf[0]
			*(*[bufoff]byte)(out[dstEvery:]) = buf[1]
			*(*[bufoff]byte)(out[dstEvery*2:]) = buf[2]
			*(*[bufoff]byte)(out[dstEvery*3:]) = buf[3]
			out = out[bufoff:]
			decoded += bufoff * 4
		}
	}
	if off > 0 {
		ioff := int(off)
		if len(out) < dstEvery*3+ioff {
			d.bufs.Put(buf)
			return nil, errors.New("corruption detected: stream overrun 3")
		}
		copy(out, buf[0][:off])
		copy(out[dstEvery:], buf[1][:off])
		copy(out[dstEvery*2:], buf[2][:off])
		copy(out[dstEvery*3:], buf[3][:off])
		decoded += int(off) * 4
		out = out[off:]
	}

	// Decode remaining.
	remainBytes := dstEvery - (decoded / 4)
	for i := range br {
		offset := dstEvery * i
		endsAt := offset + remainBytes
		if endsAt > len(out) {
			endsAt = len(out)
		}
		br := &br[i]
		bitsLeft := br.remaining()
		for bitsLeft > 0 {
			br.fill()
			if offset >= endsAt {
				d.bufs.Put(buf)
				return nil, errors.New("corruption detected: stream overrun 4")
			}

			// Read value and increment offset.
			val := br.peekBitsFast(d.actualTableLog)
			v :
    
func (d *Decoder) Decompress4X(dst, src []byte) ([]byte, error) {
	if len(d.dt.single) == 0 {
		return nil, errors.New("no table loaded")
	}
	if len(src) < 6+(4*1) {
		return nil, errors.New("input too small")
	}
	if use8BitTables && d.actualTableLog <= 8 {
		return d.decompress4X8bit(dst, src)
	}

	var br [4]bitReaderShifted
	// Decode "jump table"
	start := 6
	for i := 0; i < 3; i++ {
		length := int(src[i*2]) | (int(src[i*2+1]) << 8)
		if start+length >= len(src) {
			return nil, errors.New("truncated input (or invalid offset)")
		}
		err := br[i].init(src[start : start+length])
		if err != nil {
			return nil, err
		}
		start += length
	}
	err := br[3].init(src[start:])
	if err != nil {
		return nil, err
	}

	// destination, offset to match first output
	dstSize := cap(dst)
	dst = dst[:dstSize]
	out := dst
	dstEvery := (dstSize + 3) / 4

	const tlSize = 1 << tableLogMax
	const tlMask = tlSize - 1
	single := d.dt.single[:tlSize]

	// Use temp table to avoid bound checks/append penalty.
	buf := d.buffer()
	var off uint8
	var decoded int

	// Decode 2 values from each decoder/loop.
	const bufoff = 256
	for {
		if br[0].off < 4 || br[1].off < 4 || br[2].off < 4 || br[3].off < 4 {
			break
		}

		{
			const stream = 0
			const stream2 = 1
			br[stream].fillFast()
			br[stream2].fillFast()

			val := br[stream].peekBitsFast(d.actualTableLog)
			val2 := br[stream2].peekBitsFast(d.actualTableLog)
			v := single[val&tlMask]
			v2 := single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off] = uint8(v.entry >> 8)
			buf[stream2][off] = uint8(v2.entry >> 8)

			val = br[stream].peekBitsFast(d.actualTableLog)
			val2 = br[stream2].peekBitsFast(d.actualTableLog)
			v = single[val&tlMask]
			v2 = single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off+1] = uint8(v.entry >> 8)
			buf[stream2][off+1] = uint8(v2.entry >> 8)
		}

		{
			const stream = 2
			const stream2 = 3
			br[stream].fillFast()
			br[stream2].fillFast()

			val := br[stream].peekBitsFast(d.actualTableLog)
			val2 := br[stream2].peekBitsFast(d.actualTableLog)
			v := single[val&tlMask]
			v2 := single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off] = uint8(v.entry >> 8)
			buf[stream2][off] = uint8(v2.entry >> 8)

			val = br[stream].peekBitsFast(d.actualTableLog)
			val2 = br[stream2].peekBitsFast(d.actualTableLog)
			v = single[val&tlMask]
			v2 = single[val2&tlMask]
			br[stream].advance(uint8(v.entry))
			br[stream2].advance(uint8(v2.entry))
			buf[stream][off+1] = uint8(v.entry >> 8)
			buf[stream2][off+1] = uint8(v2.entry >> 8)
		}

		off += 2

		if off == 0 {
			if bufoff > dstEvery {
				d.bufs.Put(buf)
				return nil, errors.New("corruption detected: stream overrun 1")
			}
			// There must at least be 3 buffers left.
			if len(out)-bufoff < dstEvery*3 {
				d.bufs.Put(buf)
				return nil, errors.New("corruption detected: stream overrun 2")
			}
			//copy(out, buf[0][:])
			//copy(out[dstEvery:], buf[1][:])
			//copy(out[dstEvery*2:], buf[2][:])
			//copy(out[dstEvery*3:], buf[3][:])
			*(*[bufoff]byte)(out) = buf[0]
			*(*[bufoff]byte)(out[dstEvery:]) = buf[1]
			*(*[bufoff]byte)(out[dstEvery*2:]) = buf[2]
			*(*[bufoff]byte)(out[dstEvery*3:]) = buf[3]
			out = out[bufoff:]
			decoded += bufoff * 4
		}
	}
	if off > 0 {
		ioff := int(off)
		if len(out) < dstEvery*3+ioff {
			d.bufs.Put(buf)
			return nil, errors.New("corruption detected: stream overrun 3")
		}
		copy(out, buf[0][:off])
		copy(out[dstEvery:], buf[1][:off])
		copy(out[dstEvery*2:], buf[2][:off])
		copy(out[dstEvery*3:], buf[3][:off])
		decoded += int(off) * 4
		out = out[off:]
	}

	// Decode remaining.
	remainBytes := dstEvery - (decoded / 4)
	for i := range br {
		offset := dstEvery * i
		endsAt := offset + remainBytes
		if endsAt > len(out) {
			endsAt = len(out)
		}
		br := &br[i]
		bitsLeft := br.remaining()
		for bitsLeft > 0 {
			br.fill()
			if offset >= endsAt {
				d.bufs.Put(buf)
				return nil, errors.New("corruption detected: stream overrun 4")
			}

			// Read value and increment offset.
			val := br.peekBitsFast(d.actualTableLog)
			v := single[val&tlMask].entry
			nBits := uint8(v)
			br.advance(nBits)
			bitsLeft -= uint(nBits)
			out[offset] = uint8(v >> 8)
			offset++
		}
		if offset != endsAt {
			d.bufs.Put(buf)
			return nil, fmt.Errorf("corruption detected: short output block %d, end %d != %d", i, offset, endsAt)
		}
		decoded += offset - dstEvery*i
		err = br.close()
		if err != nil {
			return nil, err
		}
	}
	d.bufs.Put(buf)
	if dstSize != decoded {
		return nil, errors.New("corruption detected: short output block")
	}
	return dst, nil
}