Method folderReader

struct.go:261–339

nolint:cyclop,funlen,lll

(r io.ReaderAt, folder int, password string)

//nolint:cyclop,funlen,lll
func (si *streamsInfo) folderReader(r io.ReaderAt, folder int, password string) (*folderReadCloser, uint32, bool, error) {
	f := si.unpackInfo.folder[folder]
	in := make([]io.ReadCloser, f.in)
	out := make([]io.ReadCloser, f.out)

	packedOffset := 0
	for i := range folder {
		packedOffset += len(si.unpackInfo.folder[i].packed)
	}

	offset := int64(0)

	for i, input := range f.packed {
		size := int64(si.packInfo.size[packedOffset+i]) //nolint:gosec
		in[input] = util.NopCloser(bufio.NewReader(io.NewSectionReader(r, si.folderOffset(folder)+offset, size)))
		offset += size
	}

	var (
		hasEncryption bool
		input, output uint64
	)

	for i, c := range f.coder {
		if c.out != 1 {
			return nil, 0, hasEncryption, errMultipleOutputStreams
		}

		for j := input; j < input+c.in; j++ {
			if in[j] != nil {
				continue
			}

			bp := f.findInBindPair(j)
			if bp == nil || out[bp.out] == nil {
				return nil, 0, hasEncryption, errNoBoundStream
			}

			in[j] = out[bp.out]
		}

		var (
			isEncrypted bool
			err         error
		)

		out[output], isEncrypted, err = f.coderReader(in[input:input+c.in], uint64(i), password)
		if err != nil {
			return nil, 0, hasEncryption, err
		}

		if isEncrypted {
			hasEncryption = true
		}

		input += c.in
		output += c.out
	}