simdjson decoder for OTEL

simd.go

func (o *OTEL) DecodeSIMD(data []byte, pj *simdjson.ParsedJson) (*simdjson.ParsedJson, error) {
	pj, err := simdjson.Parse(data, pj, simdjson.WithCopyStrings(false))
	if err != nil {
		return nil, err
	}

	var decodeErr error
	if err := pj.ForEach(func(i simdjson.Iter) error {
		if i.Type() != simdjson.TypeObject {
			return errors.Errorf("expected object, got %v", i.Type())
		}

		obj, err := i.Object(nil)
		if err != nil {
			return errors.Wrap(err, "object")
		}

		if err := obj.ForEach(func(key []byte, i simdjson.Iter) {
			if decodeErr != nil {
				return // Skip if we already have an error
			}

			switch string(key) {
			case "Body":
				// HACK: use StringBytes to get raw bytes without allocation.
				v, err := i.StringBytes()
				if err != nil {
					decodeErr = errors.Wrap(err, "body")
					return
				}
				o.Body = v
			case "SeverityNumber":
				v, err := i.Uint()
				if err != nil {
					decodeErr = errors.Wrap(err, "severity number")
					return
				}
				o.Severity = byte(v)
			case "SeverityText":
				// Skip
			case "Timestamp":
				v, err := i.StringBytes()
				if err != nil {
					decodeErr = errors.Wrap(err, "timestamp")
					return
				}
				o.Timestamp = append(o.Timestamp[:0], v...)
			case "TraceId":
				v, err := i.StringBytes()
				if err != nil {
					decodeErr = errors.Wrap(err, "trace id")
					return
				}
				if _, err := hex.Decode(o.TraceID[:], v); err != nil {
					decodeErr = errors.Wrap(err, "trace id decode")
					return
				}
			case "SpanId":
				v, err := i.StringBytes()
				if err != nil {
					decodeErr = errors.Wrap(err, "span id")
					return
				}
				if _, err := hex.Decode(o.SpanID[:], v); err != nil {
					decodeErr = errors.Wrap(err, "span id decode")
					return
				}
			case "Attributes":
				if err := decodeMapSIMD(&o.Attributes, &i); err != nil {
					decodeErr = errors.Wrap(err, "attributes")
					return
				}
			case "Resource":
				if err := decodeMapSIMD(&o.Resource, &i); err != nil {
					decodeErr = errors.Wrap(err, "resource")
					return
				}
			}
		}, nil); err != nil {
			return err
		}

		return decodeErr
	}); err != nil {
		return nil, err
	}

	return pj, nil
}