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[79.124.17.100]) by mx.google.com with ESMTP id 4fb4d7f45d1cf-57a31c76e06si6242026a12.410.2024.06.05.03.00.13; Wed, 05 Jun 2024 03:00:13 -0700 (PDT) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@haasn.xyz header.s=mail header.b=M4nXegBG; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id D553368D6EC; Wed, 5 Jun 2024 13:00:09 +0300 (EEST) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from haasn.dev (haasn.dev [78.46.187.166]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 7C13C68D50D for ; Wed, 5 Jun 2024 13:00:02 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=haasn.xyz; s=mail; t=1717581601; bh=2QbDte8zuF4QVAIS2adVIq+QS34pTSMMFqcpgc6t7pc=; h=From:To:Cc:Subject:Date:From; b=M4nXegBG9SnjBHsXMTRd8nKdXUPPIRfCrcXqDzEGmphlz7/Kk4mrPCkT/Fry8FWmq pI980CodSZbJCOIS1VbfLRtMkKPydpSwQ0ulkhewsTOjjA460pqSjntY5ASngFi2x7 yVKgY/eRxSB4xnu7VdVX8U6xp1xoJNsj1gSTz568= Received: from haasn.dev (unknown [10.30.0.2]) by haasn.dev (Postfix) with ESMTP id B326140C0A; Wed, 5 Jun 2024 12:00:01 +0200 (CEST) From: Niklas Haas To: ffmpeg-devel@ffmpeg.org Date: Wed, 5 Jun 2024 11:59:59 +0200 Message-ID: <20240605095959.17135-1-ffmpeg@haasn.xyz> X-Mailer: git-send-email 2.45.1 MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH] avcodec/dovi_rpudec: replace brittle struct copying code X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Cc: Niklas Haas Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" X-TUID: NjuphTOpn7p5 From: Niklas Haas This code was unnecessarily trying to be robust against downgrades of libavutil (relative to the version libavcodec was compiled against), but in the process, ended up with very brittle code that is easy to accidentally forget to update when adding new fields. Instead, do the obvious thing and just directly copy the parts of the struct known at compile time. Since it is not generally supported to link against a version of libavutil older than the version libavcodec was compiled against, the struct shrinking externally is not a case we need to be worrying about. --- libavcodec/dovi_rpudec.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/libavcodec/dovi_rpudec.c b/libavcodec/dovi_rpudec.c index 7c7eda9d09..adf2c00cf5 100644 --- a/libavcodec/dovi_rpudec.c +++ b/libavcodec/dovi_rpudec.c @@ -56,14 +56,12 @@ int ff_dovi_attach_side_data(DOVIContext *s, AVFrame *frame) return AVERROR(ENOMEM); } - /* Copy only the parts of these structs known to us at compiler-time. */ -#define COPY(t, a, b, last) memcpy(a, b, offsetof(t, last) + sizeof((b)->last)) - COPY(AVDOVIRpuDataHeader, av_dovi_get_header(dovi), &s->header, disable_residual_flag); - COPY(AVDOVIDataMapping, av_dovi_get_mapping(dovi), s->mapping, nlq_pivots); - COPY(AVDOVIColorMetadata, av_dovi_get_color(dovi), s->color, source_diagonal); - ext_sz = FFMIN(sizeof(AVDOVIDmData), dovi->ext_block_size); + *av_dovi_get_header(dovi) = s->header; + *av_dovi_get_mapping(dovi) = *s->mapping; + *av_dovi_get_color(dovi) = *s->color; + av_assert0(dovi->ext_block_size >= sizeof(AVDOVIDmData)); for (int i = 0; i < s->num_ext_blocks; i++) - memcpy(av_dovi_get_ext(dovi, i), &s->ext_blocks[i], ext_sz); + *av_dovi_get_ext(dovi, i) = s->ext_blocks[i]; dovi->num_ext_blocks = s->num_ext_blocks; return 0; }