func()

in wim/wim.go [465:523]

• 52 lines of code
• 12 McCabe index (conditional complexity)

func (r *Reader) readOffsetTable(res *resourceDescriptor) (map[SHA1Hash]resourceDescriptor, []*Image, error) {
	fileData := make(map[SHA1Hash]resourceDescriptor)
	var images []*Image

	offsetTable, err := r.readResource(res)
	if err != nil {
		return nil, nil, &ParseError{Oper: "offset table", Err: err}
	}

	br := bytes.NewReader(offsetTable)
	for i := 0; ; i++ {
		var res streamDescriptor
		err := binary.Read(br, binary.LittleEndian, &res)
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, nil, &ParseError{Oper: "offset table", Err: err}
		}
		if res.Flags()&^supportedResFlags != 0 {
			return nil, nil, &ParseError{Oper: "offset table", Err: errors.New("unsupported resource flag")}
		}

		// Validation for ad-hoc testing
		if validate {
			sec, err := r.resourceReader(&res.resourceDescriptor)
			if err != nil {
				panic(fmt.Sprint(i, err))
			}
			hash := sha1.New()
			_, err = io.Copy(hash, sec)
			sec.Close()
			if err != nil {
				panic(fmt.Sprint(i, err))
			}
			var cmphash SHA1Hash
			copy(cmphash[:], hash.Sum(nil))
			if cmphash != res.Hash {
				panic(fmt.Sprint(i, "hash mismatch"))
			}
		}

		if res.Flags()&resFlagMetadata != 0 {
			image := &Image{
				wim:    r,
				offset: res.resourceDescriptor,
			}
			images = append(images, image)
		} else {
			fileData[res.Hash] = res.resourceDescriptor
		}
	}

	if len(images) != int(r.hdr.ImageCount) {
		return nil, nil, &ParseError{Oper: "offset table", Err: errors.New("mismatched image count")}
	}

	return fileData, images, nil
}