BIG rewrite stream info

pkg/mpjpeg/multipart.go

@@ -0,0 +1,56 @@
+package mpjpeg
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"net/http"
+	"net/textproto"
+	"strconv"
+	"strings"
+)
+
+func Next(rd *bufio.Reader) (http.Header, []byte, error) {
+	for {
+		// search next boundary and skip empty lines
+		s, err := rd.ReadString('\n')
+		if err != nil {
+			return nil, nil, err
+		}
+
+		if strings.HasPrefix(s, "--") {
+			break
+		}
+
+		if s == "\r\n" {
+			continue
+		}
+
+		return nil, nil, errors.New("multipart: wrong boundary: " + s)
+	}
+
+	tp := textproto.NewReader(rd)
+	header, err := tp.ReadMIMEHeader()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	s := header.Get("Content-Length")
+	if s == "" {
+		return nil, nil, errors.New("multipart: no content length")
+	}
+
+	size, err := strconv.Atoi(s)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	buf := make([]byte, size)
+	if _, err = io.ReadFull(rd, buf); err != nil {
+		return nil, nil, err
+	}
+
+	_, _ = rd.Discard(2) // skip "\r\n"
+
+	return http.Header(header), buf, nil
+}