Replace computations of remaining bits with calls to get_bits_left().

(cherry picked from commit 3574a85ce57366ba7429edef93d5cad8640fb68c)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>

10 files changed, 18 insertions, 19 deletions

diff --git a/libavcodec/escape124.c b/libavcodec/escape124.c
index f6d7c8268e..9efafdbf12 100644
--- a/libavcodec/escape124.c
+++ b/libavcodec/escape124.c
@@ -49,7 +49,7 @@ typedef struct Escape124Context {
 } Escape124Context;
 
 static int can_safely_read(GetBitContext* gb, int bits) {
-    return get_bits_count(gb) + bits <= gb->size_in_bits;
+    return get_bits_left(gb) >= bits;
 }
 
 /**
diff --git a/libavcodec/h261dec.c b/libavcodec/h261dec.c
index 66ea4be2a1..0be0134f01 100644
--- a/libavcodec/h261dec.c
+++ b/libavcodec/h261dec.c
@@ -265,7 +265,7 @@ static int h261_decode_mb(H261Context *h){
     while( h->mba_diff == MBA_STUFFING ); // stuffing
 
     if ( h->mba_diff < 0 ){
-        if ( get_bits_count(&s->gb) + 7 >= s->gb.size_in_bits )
+        if (get_bits_left(&s->gb) <= 7)
             return SLICE_END;
 
         av_log(s->avctx, AV_LOG_ERROR, "illegal mba at %d %d\n", s->mb_x, s->mb_y);
diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index ba0ea4f9f9..55562148cf 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -650,7 +650,7 @@ retry:
     ret = decode_slice(s);
     while(s->mb_y<s->mb_height){
         if(s->msmpeg4_version){
-            if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
+            if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_left(&s->gb)<0)
                 break;
         }else{
             int prev_x=s->mb_x, prev_y=s->mb_y;
diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 46e6c72832..d09c4aca2e 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -3666,7 +3666,7 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg){
                 if(s->mb_y >= s->mb_height){
                     tprintf(s->avctx, "slice end %d %d\n", get_bits_count(&s->gb), s->gb.size_in_bits);
 
-                    if(get_bits_count(&s->gb) == s->gb.size_in_bits ) {
+                    if (get_bits_left(&s->gb) == 0) {
                         ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END&part_mask);
 
                         return 0;
@@ -3678,9 +3678,9 @@ static int decode_slice(struct AVCodecContext *avctx, void *arg){
                 }
             }
 
-            if(get_bits_count(&s->gb) >= s->gb.size_in_bits && s->mb_skip_run<=0){
+            if (get_bits_left(&s->gb) <= 0 && s->mb_skip_run <= 0){
                 tprintf(s->avctx, "slice end %d %d\n", get_bits_count(&s->gb), s->gb.size_in_bits);
-                if(get_bits_count(&s->gb) == s->gb.size_in_bits ){
+                if (get_bits_left(&s->gb) == 0) {
                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END&part_mask);
                     if (s->mb_x > lf_x_start) loop_filter(h, lf_x_start, s->mb_x);
 
diff --git a/libavcodec/h264_ps.c b/libavcodec/h264_ps.c
index 76bf116a3f..287702c7c4 100644
--- a/libavcodec/h264_ps.c
+++ b/libavcodec/h264_ps.c
@@ -227,8 +227,8 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
         sps->num_reorder_frames= get_ue_golomb(&s->gb);
         get_ue_golomb(&s->gb); /*max_dec_frame_buffering*/
 
-        if(s->gb.size_in_bits < get_bits_count(&s->gb)){
-            av_log(h->s.avctx, AV_LOG_ERROR, "Overread VUI by %d bits\n", get_bits_count(&s->gb) - s->gb.size_in_bits);
+        if (get_bits_left(&s->gb) < 0) {
+            av_log(h->s.avctx, AV_LOG_ERROR, "Overread VUI by %d bits\n", -get_bits_left(&s->gb));
             sps->num_reorder_frames=0;
             sps->bitstream_restriction_flag= 0;
         }
diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
index 4f52bbe969..2e5fb65f0d 100644
--- a/libavcodec/h264_sei.c
+++ b/libavcodec/h264_sei.c
@@ -164,7 +164,7 @@ static int decode_buffering_period(H264Context *h){
 int ff_h264_decode_sei(H264Context *h){
     MpegEncContext * const s = &h->s;
 
-    while(get_bits_count(&s->gb) + 16 < s->gb.size_in_bits){
+    while (get_bits_left(&s->gb) > 16) {
         int size, type;
 
         type=0;
diff --git a/libavcodec/huffyuv.c b/libavcodec/huffyuv.c
index 2e1db043ea..a173a13d87 100644
--- a/libavcodec/huffyuv.c
+++ b/libavcodec/huffyuv.c
@@ -720,7 +720,7 @@ static void decode_422_bitstream(HYuvContext *s, int count){
     count/=2;
 
     if(count >= (get_bits_left(&s->gb))/(31*4)){
-        for(i=0; i<count && get_bits_count(&s->gb) < s->gb.size_in_bits; i++){
+        for (i = 0; i < count && get_bits_left(&s->gb) > 0; i++) {
             READ_2PIX(s->temp[0][2*i  ], s->temp[1][i], 1);
             READ_2PIX(s->temp[0][2*i+1], s->temp[2][i], 2);
         }
@@ -738,7 +738,7 @@ static void decode_gray_bitstream(HYuvContext *s, int count){
     count/=2;
 
     if(count >= (get_bits_left(&s->gb))/(31*2)){
-        for(i=0; i<count && get_bits_count(&s->gb) < s->gb.size_in_bits; i++){
+        for (i = 0; i < count && get_bits_left(&s->gb) > 0; i++) {
             READ_2PIX(s->temp[0][2*i  ], s->temp[0][2*i+1], 0);
         }
     }else{
diff --git a/libavcodec/ituh263dec.c b/libavcodec/ituh263dec.c
index 148bb33a36..3d82e5c382 100644
--- a/libavcodec/ituh263dec.c
+++ b/libavcodec/ituh263dec.c
@@ -852,8 +852,8 @@ end:
     {
         int v= show_bits(&s->gb, 16);
 
-        if(get_bits_count(&s->gb) + 16 > s->gb.size_in_bits){
-            v>>= get_bits_count(&s->gb) + 16 - s->gb.size_in_bits;
+        if (get_bits_left(&s->gb) < 16) {
+            v >>= 16 - get_bits_left(&s->gb);
         }
 
         if(v==0)
diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 49d334bb7e..a7950287e2 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -858,9 +858,9 @@ static int mjpeg_decode_scan(MJpegDecodeContext *s, int nb_components, int Ah,
             if (s->restart_interval && !s->restart_count)
                 s->restart_count = s->restart_interval;
 
-            if (get_bits_count(&s->gb)>s->gb.size_in_bits) {
+            if (get_bits_left(&s->gb) < 0) {
                 av_log(s->avctx, AV_LOG_ERROR, "overread %d\n",
-                       get_bits_count(&s->gb) - s->gb.size_in_bits);
+                       -get_bits_left(&s->gb));
                 return -1;
             }
             for (i = 0; i < nb_components; i++) {
@@ -1151,7 +1151,7 @@ static int mjpeg_decode_app(MJpegDecodeContext *s)
     len = get_bits(&s->gb, 16);
     if (len < 5)
         return -1;
-    if (8 * len + get_bits_count(&s->gb) > s->gb.size_in_bits)
+    if (8 * len > get_bits_left(&s->gb))
         return -1;
 
     id   = get_bits_long(&s->gb, 32);
@@ -1292,8 +1292,7 @@ out:
 static int mjpeg_decode_com(MJpegDecodeContext *s)
 {
     int len = get_bits(&s->gb, 16);
-    if (len >= 2 &&
-        8 * len - 16 + get_bits_count(&s->gb) <= s->gb.size_in_bits) {
+    if (len >= 2 && 8 * len - 16 <= get_bits_left(&s->gb)) {
         char *cbuf = av_malloc(len - 1);
         if (cbuf) {
             int i;
diff --git a/libavcodec/vp6.c b/libavcodec/vp6.c
index e4783c6e84..91377015eb 100644
--- a/libavcodec/vp6.c
+++ b/libavcodec/vp6.c
@@ -387,7 +387,7 @@ static void vp6_parse_coeff_huffman(VP56Context *s)
                 if (coeff_idx)
                     break;
             } else {
-                if (get_bits_count(&s->gb) >= s->gb.size_in_bits)
+                if (get_bits_left(&s->gb) <= 0)
                     return;
                 coeff = get_vlc2(&s->gb, vlc_coeff->table, 9, 3);
                 if (coeff == 0) {