avcodec/get_bits: add skip_1stop_8data_bits

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/get_bits.h

@@ -585,6 +585,20 @@ static inline int get_bits_left(GetBitContext *gb)
     return gb->size_in_bits - get_bits_count(gb);
 }
 
+static inline int skip_1stop_8data_bits(GetBitContext *gb)
+{
+    if (get_bits_left(gb) <= 0)
+        return AVERROR_INVALIDDATA;
+
+    while (get_bits1(gb)) {
+        skip_bits(gb, 8);
+        if (get_bits_left(gb) <= 0)
+            return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
+
 //#define TRACE
 
 #ifdef TRACE