move base elements into base folder

base/utils.go

@@ -0,0 +1,77 @@
+package base
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strconv"
+)
+
+const (
+	rtspMaxContentLength = 4096
+)
+
+func readByteEqual(rb *bufio.Reader, cmp byte) error {
+	byt, err := rb.ReadByte()
+	if err != nil {
+		return err
+	}
+
+	if byt != cmp {
+		return fmt.Errorf("expected '%c', got '%c'", cmp, byt)
+	}
+
+	return nil
+}
+
+func readBytesLimited(rb *bufio.Reader, delim byte, n int) ([]byte, error) {
+	for i := 1; i <= n; i++ {
+		byts, err := rb.Peek(i)
+		if err != nil {
+			return nil, err
+		}
+
+		if byts[len(byts)-1] == delim {
+			rb.Discard(len(byts))
+			return byts, nil
+		}
+	}
+	return nil, fmt.Errorf("buffer length exceeds %d", n)
+}
+
+func readContent(rb *bufio.Reader, header Header) ([]byte, error) {
+	cls, ok := header["Content-Length"]
+	if !ok || len(cls) != 1 {
+		return nil, nil
+	}
+
+	cl, err := strconv.ParseInt(cls[0], 10, 64)
+	if err != nil {
+		return nil, fmt.Errorf("invalid Content-Length")
+	}
+
+	if cl > rtspMaxContentLength {
+		return nil, fmt.Errorf("Content-Length exceeds %d", rtspMaxContentLength)
+	}
+
+	ret := make([]byte, cl)
+	n, err := io.ReadFull(rb, ret)
+	if err != nil && n != len(ret) {
+		return nil, err
+	}
+
+	return ret, nil
+}
+
+func writeContent(bw *bufio.Writer, content []byte) error {
+	if len(content) == 0 {
+		return nil
+	}
+
+	_, err := bw.Write(content)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}