avcodec/motion_est, mpegvideo: Make pointers to static storage const

Modifying static storage must not happen because of multithreading
(except initialization of course), so add const to the pointed-to type
for pointers that point to static storage.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/motion_est.c

@@ -578,7 +578,7 @@ static inline int h263_mv4_search(MpegEncContext *s, int mx, int my, int shift)
     int dmin_sum=0, mx4_sum=0, my4_sum=0, i;
     int same=1;
     const int stride= c->stride;
-    uint8_t *mv_penalty= c->current_mv_penalty;
+    const uint8_t *mv_penalty = c->current_mv_penalty;
     int safety_clipping= s->unrestricted_mv && (s->width&15) && (s->height&15);
 
     init_mv4_ref(c);
@@ -743,7 +743,7 @@ static int interlaced_search(MpegEncContext *s, int ref_index,
     const int h=8;
     int block;
     int P[10][2];
-    uint8_t * const mv_penalty= c->current_mv_penalty;
+    const uint8_t * const mv_penalty = c->current_mv_penalty;
     int same=1;
     const int stride= 2*s->linesize;
     int dmin_sum= 0;
@@ -1120,7 +1120,7 @@ static int estimate_motion_b(MpegEncContext *s, int mb_x, int mb_y,
     const int shift= 1+s->quarter_sample;
     const int mot_stride = s->mb_stride;
     const int mot_xy = mb_y*mot_stride + mb_x;
-    uint8_t * const mv_penalty= c->mv_penalty[f_code] + MAX_DMV;
+    const uint8_t * const mv_penalty = c->mv_penalty[f_code] + MAX_DMV;
     int mv_scale;
 
     c->penalty_factor    = get_penalty_factor(s->lambda, s->lambda2, c->avctx->me_cmp);
@@ -1184,8 +1184,8 @@ static inline int check_bidir_mv(MpegEncContext * s,
     //FIXME better f_code prediction (max mv & distance)
     //FIXME pointers
     MotionEstContext * const c= &s->me;
-    uint8_t * const mv_penalty_f= c->mv_penalty[s->f_code] + MAX_DMV; // f_code of the prev frame
-    uint8_t * const mv_penalty_b= c->mv_penalty[s->b_code] + MAX_DMV; // f_code of the prev frame
+    const uint8_t * const mv_penalty_f = c->mv_penalty[s->f_code] + MAX_DMV; // f_code of the prev frame
+    const uint8_t * const mv_penalty_b = c->mv_penalty[s->b_code] + MAX_DMV; // f_code of the prev frame
     int stride= c->stride;
     uint8_t *dest_y = c->scratchpad;
     uint8_t *ptr;
@@ -1600,7 +1600,7 @@ int ff_get_best_fcode(MpegEncContext * s, int16_t (*mv_table)[2], int type)
     if (s->motion_est != FF_ME_ZERO) {
         int score[8];
         int i, y, range= s->avctx->me_range ? s->avctx->me_range : (INT_MAX/2);
-        uint8_t * fcode_tab= s->fcode_tab;
+        const uint8_t * fcode_tab = s->fcode_tab;
         int best_fcode=-1;
         int best_score=-10000000;
 

libavcodec/motion_est.h

@@ -90,8 +90,8 @@ typedef struct MotionEstContext {
     op_pixels_func(*hpel_avg)[4];
     qpel_mc_func(*qpel_put)[16];
     qpel_mc_func(*qpel_avg)[16];
-    uint8_t (*mv_penalty)[MAX_DMV * 2 + 1]; ///< bit amount needed to encode a MV
-    uint8_t *current_mv_penalty;
+    const uint8_t (*mv_penalty)[MAX_DMV * 2 + 1]; ///< bit amount needed to encode a MV
+    const uint8_t *current_mv_penalty;
     int (*sub_motion_search)(struct MpegEncContext *s,
                              int *mx_ptr, int *my_ptr, int dmin,
                              int src_index, int ref_index,

libavcodec/motion_est_template.c

@@ -34,7 +34,7 @@
     const int av_unused ymin= c->ymin;\
     const int av_unused xmax= c->xmax;\
     const int av_unused ymax= c->ymax;\
-    uint8_t *mv_penalty= c->current_mv_penalty;\
+    const uint8_t *mv_penalty = c->current_mv_penalty; \
     const int pred_x= c->pred_x;\
     const int pred_y= c->pred_y;\
 

libavcodec/mpegvideo.h

@@ -276,7 +276,7 @@ typedef struct MpegEncContext {
     int mv[2][4][2];
     int field_select[2][2];
     int last_mv[2][2][2];             ///< last MV, used for MV prediction in MPEG-1 & B-frame MPEG-4
-    uint8_t *fcode_tab;               ///< smallest fcode needed for each MV
+    const uint8_t *fcode_tab;         ///< smallest fcode needed for each MV
     int16_t direct_scale_mv[2][64];   ///< precomputed to avoid divisions in ff_mpeg4_set_direct_mv
 
     MotionEstContext me;