[FFmpeg-cvslog] avcodec/magicyuv: Reuse array instead of using multiple arrays

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Mon Aug 31 19:55:28 2020 +0200| [aae499f77a1d9f9083486fc7d98baf63e0ab917f] | committer: Andreas Rheinhardt

avcodec/magicyuv: Reuse array instead of using multiple arrays

The lengths of the VLC codes are implicitly contained in the VLC tables
itself; apart from that they are not used lateron. So it is unnecessary
to store them and the very same array can be reused to parse the Huffman
table for the next plane.

Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=aae499f77a1d9f9083486fc7d98baf63e0ab917f
---

 libavcodec/magicyuv.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/magicyuv.c b/libavcodec/magicyuv.c
index 9282b39723..a16135e683 100644
--- a/libavcodec/magicyuv.c
+++ b/libavcodec/magicyuv.c
@@ -68,7 +68,7 @@ typedef struct MagicYUVContext {
     int               vshift[4];
     Slice            *slices[4];      // slice bitstream positions for each plane
     unsigned int      slices_size[4]; // slice sizes for each plane
-    uint8_t           len[4][4096];   // table of code lengths for each plane
+    uint8_t           len[4096];      // scratch table of code lengths
     VLC               vlc[4];         // VLC for each plane
     int (*huff_build)(VLC *vlc, uint8_t *len);
     int (*magy_decode_slice)(AVCodecContext *avctx, void *tdata,
@@ -465,11 +465,11 @@ static int build_huffman(AVCodecContext *avctx, GetBitContext *gbit, int max)
         }
 
         for (; j < k; j++)
-            s->len[i][j] = x;
+            s->len[j] = x;
 
         if (j == max) {
             j = 0;
-            if (s->huff_build(&s->vlc[i], s->len[i])) {
+            if (s->huff_build(&s->vlc[i], s->len)) {
                 av_log(avctx, AV_LOG_ERROR, "Cannot build Huffman codes\n");
                 return AVERROR_INVALIDDATA;
             }