Deserializer

resp/deserializer.go

@@ -0,0 +1,111 @@
+package resp
+
+import (
+	"bufio"
+	"errors"
+	"strconv"
+	"strings"
+)
+
+func Deserialize(reader *bufio.Reader) (Value, error) {
+	firstByte, err := reader.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+
+	switch firstByte {
+	case '+':
+		return DeserializerSimpleString(reader)
+	case '-':
+		return DeserializerError(reader)
+	case ':':
+		return DeserializerInteger(reader)
+	case '$':
+		return DeserializerBulkString(reader)
+	case '*':
+		return DeserializerArray(reader)
+	default:
+		return nil, errors.New("unknown RESP data type")
+	}
+}
+
+func DeserializerSimpleString(reader *bufio.Reader) (SimpleString, error) {
+	line, err := reader.ReadString('\n')
+	if err != nil {
+		return SimpleString{}, err
+	}
+
+	return SimpleString{Value: strings.TrimRight(line, "\r\n")}, nil
+}
+
+func DeserializerError(reader *bufio.Reader) (Error, error) {
+	line, err := reader.ReadString('\n')
+	if err != nil {
+		return Error{}, err
+	}
+
+	return Error{Value: strings.TrimRight(line, "\r\n")}, nil
+}
+
+func DeserializerInteger(reader *bufio.Reader) (Integer, error) {
+	line, err := reader.ReadString('\n')
+	if err != nil {
+		return Integer{}, err
+	}
+	i, err := strconv.ParseInt(strings.TrimRight(line, "\r\n"), 10, 64)
+	if err != nil {
+		return Integer{}, err
+	}
+
+	return Integer{Value: i}, nil
+}
+
+func DeserializerBulkString(reader *bufio.Reader) (BulkString, error) {
+	lengthStr, err := reader.ReadString('\n')
+	if err != nil {
+		return BulkString{}, err
+	}
+
+	length, err := strconv.Atoi(strings.TrimRight(lengthStr, "\r\n"))
+	if err != nil {
+		return BulkString{}, err
+	}
+
+	if length == -1 {
+		return BulkString{IsNull: true}, nil
+	}
+
+	buf := make([]byte, length+2)
+	_, err = reader.Read(buf)
+	if err != nil {
+		return BulkString{}, err
+	}
+	return BulkString{Value: string(buf[:length])}, nil
+}
+
+func DeserializerArray(reader *bufio.Reader) (Array, error) {
+	lengthLine, err := reader.ReadString('\n')
+	if err != nil {
+		return Array{}, err
+	}
+
+	length, err := strconv.Atoi(strings.TrimRight(lengthLine, "\r\n"))
+	if err != nil {
+		return Array{}, err
+	}
+
+	if length == -1 {
+		return Array{IsNull: true}, nil
+	}
+
+	values := make([]Value, length)
+	for i := range length {
+		v, err := Deserialize(reader)
+		if err != nil {
+			return Array{}, err
+		}
+		values[i] = v
+	}
+
+	return Array{Values: values}, nil
+}