vc1dec: Check group allocations separatedly

This avoids accessing NULL pointers in case of error.

libavcodec/vc1dec.c

@@ -324,31 +324,50 @@ av_cold int ff_vc1_decode_init_alloc_tables(VC1Context *v)
     v->fieldtx_plane    = av_mallocz(s->mb_stride * mb_height);
     v->acpred_plane     = av_malloc (s->mb_stride * mb_height);
     v->over_flags_plane = av_malloc (s->mb_stride * mb_height);
+    if (!v->mv_type_mb_plane || !v->direct_mb_plane || !v->forward_mb_plane ||
+        !v->fieldtx_plane || !v->acpred_plane || !v->over_flags_plane)
+        goto error;
 
     v->n_allocated_blks = s->mb_width + 2;
     v->block            = av_malloc(sizeof(*v->block) * v->n_allocated_blks);
     v->cbp_base         = av_malloc(sizeof(v->cbp_base[0]) * 2 * s->mb_stride);
+    if (!v->block || !v->cbp_base)
+        goto error;
     v->cbp              = v->cbp_base + s->mb_stride;
     v->ttblk_base       = av_malloc(sizeof(v->ttblk_base[0]) * 2 * s->mb_stride);
+    if (!v->ttblk_base)
+        goto error;
     v->ttblk            = v->ttblk_base + s->mb_stride;
     v->is_intra_base    = av_mallocz(sizeof(v->is_intra_base[0]) * 2 * s->mb_stride);
+    if (!v->is_intra_base)
+        goto error;
     v->is_intra         = v->is_intra_base + s->mb_stride;
     v->luma_mv_base     = av_malloc(sizeof(v->luma_mv_base[0]) * 2 * s->mb_stride);
+    if (!v->luma_mv_base)
+        goto error;
     v->luma_mv          = v->luma_mv_base + s->mb_stride;
 
     /* allocate block type info in that way so it could be used with s->block_index[] */
     v->mb_type_base = av_malloc(s->b8_stride * (mb_height * 2 + 1) + s->mb_stride * (mb_height + 1) * 2);
+    if (!v->mb_type_base)
+        goto error;
     v->mb_type[0]   = v->mb_type_base + s->b8_stride + 1;
     v->mb_type[1]   = v->mb_type_base + s->b8_stride * (mb_height * 2 + 1) + s->mb_stride + 1;
     v->mb_type[2]   = v->mb_type[1] + s->mb_stride * (mb_height + 1);
 
     /* allocate memory to store block level MV info */
     v->blk_mv_type_base = av_mallocz(     s->b8_stride * (mb_height * 2 + 1) + s->mb_stride * (mb_height + 1) * 2);
+    if (!v->blk_mv_type_base)
+        goto error;
     v->blk_mv_type      = v->blk_mv_type_base + s->b8_stride + 1;
     v->mv_f_base        = av_mallocz(2 * (s->b8_stride * (mb_height * 2 + 1) + s->mb_stride * (mb_height + 1) * 2));
+    if (!v->mv_f_base)
+        goto error;
     v->mv_f[0]          = v->mv_f_base + s->b8_stride + 1;
     v->mv_f[1]          = v->mv_f[0] + (s->b8_stride * (mb_height * 2 + 1) + s->mb_stride * (mb_height + 1) * 2);
     v->mv_f_next_base   = av_mallocz(2 * (s->b8_stride * (mb_height * 2 + 1) + s->mb_stride * (mb_height + 1) * 2));
+    if (!v->mv_f_next_base)
+        goto error;
     v->mv_f_next[0]     = v->mv_f_next_base + s->b8_stride + 1;
     v->mv_f_next[1]     = v->mv_f_next[0] + (s->b8_stride * (mb_height * 2 + 1) + s->mb_stride * (mb_height + 1) * 2);
 
@@ -362,12 +381,6 @@ av_cold int ff_vc1_decode_init_alloc_tables(VC1Context *v)
         }
     }
 
-    if (!v->mv_type_mb_plane || !v->direct_mb_plane || !v->acpred_plane || !v->over_flags_plane ||
-        !v->block || !v->cbp_base || !v->ttblk_base || !v->is_intra_base || !v->luma_mv_base ||
-        !v->mb_type_base) {
-        goto error;
-    }
-
     return 0;
 
 error: