Fix undefined expressions that use multiple calls to get_bits().

Because the order of evaluation of subexpressions is undefined, two
get_bits() calls may not be part of the same expression.

See also r24902.

Originally committed as revision 24906 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mjpegdec.c

@@ -1027,7 +1027,7 @@ static int mjpeg_decode_app(MJpegDecodeContext *s)
     if(8*len + get_bits_count(&s->gb) > s->gb.size_in_bits)
         return -1;
 
-    id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);
+    id = get_bits_long(&s->gb, 32);
     id = av_be2ne32(id);
     len -= 6;
 
@@ -1134,7 +1134,7 @@ static int mjpeg_decode_app(MJpegDecodeContext *s)
     /* Apple MJPEG-A */
     if ((s->start_code == APP1) && (len > (0x28 - 8)))
     {
-        id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);
+        id = get_bits_long(&s->gb, 32);
         id = av_be2ne32(id);
         len -= 4;
         if (id == AV_RL32("mjpg")) /* Apple MJPEG-A */

libavcodec/qdm2.c

@@ -1209,7 +1209,8 @@ static void qdm2_decode_super_block (QDM2Context *q)
     init_get_bits(&gb, header.data, header.size*8);
 
     if (header.type == 2 || header.type == 4 || header.type == 5) {
-        int csum = 257 * get_bits(&gb, 8) + 2 * get_bits(&gb, 8);
+        int csum  = 257 * get_bits(&gb, 8);
+            csum +=   2 * get_bits(&gb, 8);
 
         csum = qdm2_packet_checksum(q->compressed_data, q->checksum_size, csum);