avcodec/mjpegdec: Only keep what is used from ScanTable

Namely ScanTable.permutated.

Reviewed-by: Peter Ross <pross@xvid.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/mjpegdec.c

@@ -115,8 +115,8 @@ static void init_idct(AVCodecContext *avctx)
     MJpegDecodeContext *s = avctx->priv_data;
 
     ff_idctdsp_init(&s->idsp, avctx);
-    ff_init_scantable(s->idsp.idct_permutation, &s->scantable,
+    ff_permute_scantable(s->permutated_scantable, ff_zigzag_direct,
-                      ff_zigzag_direct);
+                         s->idsp.idct_permutation);
 }
 
 av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
@@ -846,7 +846,7 @@ static int decode_block(MJpegDecodeContext *s, int16_t *block, int component,
                 av_log(s->avctx, AV_LOG_ERROR, "error count: %d\n", i);
                 return AVERROR_INVALIDDATA;
             }
-            j        = s->scantable.permutated[i];
+            j        = s->permutated_scantable[i];
             block[j] = level * quant_matrix[i];
         }
     } while (i < 63);
@@ -909,14 +909,14 @@ static int decode_block_progressive(MJpegDecodeContext *s, int16_t *block,
 
                 if (i >= se) {
                     if (i == se) {
-                        j = s->scantable.permutated[se];
+                        j = s->permutated_scantable[se];
                         block[j] = level * (quant_matrix[se] << Al);
                         break;
                     }
                     av_log(s->avctx, AV_LOG_ERROR, "error count: %d\n", i);
                     return AVERROR_INVALIDDATA;
                 }
-                j = s->scantable.permutated[i];
+                j = s->permutated_scantable[i];
                 block[j] = level * (quant_matrix[i] << Al);
             } else {
                 if (run == 0xF) {// ZRL - skip 15 coefficients
@@ -964,7 +964,7 @@ for (; ; i++) {                                                     \
         }                                                           \
         break;                                                      \
     }                                                               \
-    j = s->scantable.permutated[i];                                 \
+    j = s->permutated_scantable[i];                                 \
     if (block[j])                                                   \
         REFINE_BIT(j)                                               \
     else if (run-- == 0)                                            \
@@ -994,7 +994,7 @@ static int decode_block_refinement(MJpegDecodeContext *s, int16_t *block,
                 val = SHOW_UBITS(re, &s->gb, 1);
                 LAST_SKIP_BITS(re, &s->gb, 1);
                 ZERO_RUN;
-                j = s->scantable.permutated[i];
+                j = s->permutated_scantable[i];
                 val--;
                 block[j] = ((quant_matrix[i] << Al) ^ val) - val;
                 if (i == se) {
@@ -1026,7 +1026,7 @@ static int decode_block_refinement(MJpegDecodeContext *s, int16_t *block,
     }
 
     for (; i <= last; i++) {
-        j = s->scantable.permutated[i];
+        j = s->permutated_scantable[i];
         if (block[j])
             REFINE_BIT(j)
     }

libavcodec/mjpegdec.h

@@ -118,7 +118,7 @@ typedef struct MJpegDecodeContext {
     uint64_t coefs_finished[MAX_COMPONENTS]; ///< bitmask of which coefs have been completely decoded (progressive mode)
     int palette_index;
     int force_pal8;
-    ScanTable scantable;
+    uint8_t permutated_scantable[64];
     BlockDSPContext bdsp;
     HpelDSPContext hdsp;
     IDCTDSPContext idsp;