Initial commit: docker compose config

server/torrshash/fields.go

@@ -0,0 +1,130 @@
+package torrshash
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+)
+
+type Field struct {
+	Tag   Tag    `json:"tag"`
+	Value string `json:"value"`
+}
+
+type Tag int
+
+const (
+	TagTitle    = iota // string
+	TagPoster          // string
+	TagTracker         // string
+	TagCategory        // string
+	TagSize            // binary
+)
+
+func (tag Tag) String() string {
+	switch tag {
+	case TagTitle:
+		return "Title"
+	case TagPoster:
+		return "Poster"
+	case TagTracker:
+		return "Tracker"
+	case TagCategory:
+		return "Category"
+	case TagSize:
+		return "Size"
+	default:
+		return "Unknown"
+	}
+}
+
+func NewField(tag Tag, value string) *Field {
+	return &Field{Tag: tag, Value: value}
+}
+
+func ReadField(reader io.Reader) (*Field, error) {
+	tagb := make([]byte, 1)
+	if _, err := reader.Read(tagb); err == io.EOF {
+		return nil, nil
+	}
+	tag := Tag(tagb[0])
+
+	if isBinary(tag) {
+		var value int64
+		err := binary.Read(reader, binary.LittleEndian, &value)
+		if err != nil {
+			return nil, err
+		}
+		return NewField(tag, strconv.FormatInt(value, 10)), nil
+	}
+
+	var length uint16
+	err := binary.Read(reader, binary.LittleEndian, &length)
+	if err != nil {
+		return nil, err
+	}
+
+	valBytes := make([]byte, length)
+	n, err := io.ReadFull(reader, valBytes)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if n != int(length) {
+		return nil, fmt.Errorf("expected to read %v bytes, read %v", length, n)
+	}
+
+	return NewField(tag, string(valBytes)), nil
+}
+
+func (f *Field) write(writer io.Writer) error {
+	value := strings.TrimSpace(f.Value)
+	if len(value) == 0 {
+		return nil
+	}
+	if isBinary(f.Tag) && value == "0" {
+		return nil
+	}
+
+	_, err := writer.Write([]byte{byte(f.Tag)})
+	if err != nil {
+		return err
+	}
+
+	if isBinary(f.Tag) {
+		ii, err := strconv.ParseInt(value, 10, 64)
+		if err != nil {
+			return err
+		}
+		if ii == 0 {
+			return nil
+		}
+		return binary.Write(writer, binary.LittleEndian, ii)
+	}
+
+	strBytes := []byte(value)
+	err = binary.Write(writer, binary.LittleEndian, uint16(len(strBytes)))
+	if err != nil {
+		return err
+	}
+	_, err = writer.Write(strBytes)
+	return err
+}
+
+func isBinary(t Tag) bool {
+	switch t {
+	case TagTitle:
+	case TagPoster:
+	case TagTracker:
+	case TagCategory:
+		return false
+	case TagSize:
+		return true
+	default:
+		return false
+	}
+	return false
+}