From 1bff2f3d929b7e1229b9a125e3cf938ece1665cc Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sat, 10 Oct 2020 06:13:21 +0200 Subject: [PATCH] avcodec/sheervideo: Improve creating VLC tables Don't needlessly copy an array around; don't create a table with default symbols; and use smaller types to save stack space: The longest code here is 16 bits, so one can store the codes in this type. Reviewed-by: Paul B Mahol Signed-off-by: Andreas Rheinhardt --- libavcodec/sheervideo.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/libavcodec/sheervideo.c b/libavcodec/sheervideo.c index ba9aecbb11..3f9b299a1e 100644 --- a/libavcodec/sheervideo.c +++ b/libavcodec/sheervideo.c @@ -1782,25 +1782,20 @@ static void decode_rgb(AVCodecContext *avctx, AVFrame *p, GetBitContext *gb) static int build_vlc(VLC *vlc, const uint8_t *len, int count) { - uint32_t codes[1024]; - uint8_t bits[1024]; - uint16_t syms[1024]; - uint64_t index; + uint16_t codes[1024]; + unsigned index; int i; index = 0; for (i = 0; i < count; i++) { - codes[i] = index >> (32 - len[i]); - bits[i] = len[i]; - syms[i] = i; - index += 1ULL << (32 - len[i]); + codes[i] = index >> (32 - len[i]); + index += 1U << (32 - len[i]); } ff_free_vlc(vlc); - return ff_init_vlc_sparse(vlc, 12, count, - bits, sizeof(*bits), sizeof(*bits), - codes, sizeof(*codes), sizeof(*codes), - syms, sizeof(*syms), sizeof(*syms), 0); + return init_vlc(vlc, 12, count, + len, sizeof(*len), sizeof(*len), + codes, sizeof(*codes), sizeof(*codes), 0); } static int decode_frame(AVCodecContext *avctx,