From patchwork Sun Feb 14 21:28:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Rheinhardt X-Patchwork-Id: 25627 Return-Path: X-Original-To: patchwork@ffaux-bg.ffmpeg.org Delivered-To: patchwork@ffaux-bg.ffmpeg.org Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by ffaux.localdomain (Postfix) with ESMTP id A0A2344A9FF for ; Sun, 14 Feb 2021 23:29:08 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 7E07D68A083; Sun, 14 Feb 2021 23:29:08 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mail-wr1-f54.google.com (mail-wr1-f54.google.com [209.85.221.54]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 9CCD0688137 for ; Sun, 14 Feb 2021 23:29:01 +0200 (EET) Received: by mail-wr1-f54.google.com with SMTP id g6so6616779wrs.11 for ; Sun, 14 Feb 2021 13:29:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CZ8hMxIGVlbpI1PP+NOyUHSJ9f9PyrmhZPGAKIvPJRk=; b=FSfXlitBN/SyOvHDYIfAlIHZErRXSgeVmqqHYv+mMQeZUCkTB18ZtlwrbErKrwi0dw oGjDuBeSgbqW6VKEMF4g8ZXYKtYLjwxvbHPgK3PimGpCTuSB8mtsJU/Jg2ceb1v6k+ES UiJb8clhDZFePds+R9gwy+mcDx0Xt7RKH4u+MCuKEZYbHGdvdFYqTwa5dGeszGfdMpt3 R+KZBXRnCsMqJYNDI7kxnkGk/Kcemu1+id4nmsfTpvsllnMCU5hcOa+WpU9qqrsJcLCy 4ULWE8WCtsupUN+8V5cqovBjKenzZnpUQ8wR3YmQmvN9/+Mvu9j/nQXFp1z9c7/SovCG EU0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CZ8hMxIGVlbpI1PP+NOyUHSJ9f9PyrmhZPGAKIvPJRk=; b=C/nDFNN2LWbTvlsVkhYdJa4zwjRPimPrNTxXmDgv68Kc0F95dv1UHPzCsJyoGoF/db 1mrYd9vxW6aZ1HwM6DFH7NuHob9QRNNV83aqtJUK38urb4TK3vHQIn2h2Ix72tQdUfGz gvT0rfcUOnqPJUBO+5hIAU3rSiD91UMC7/eV9qIurdjEujEzC3Jb+rGUypfmaVmkZGGT daDCkeQrglB0EInyxSNlzTEV7jVgdBu1fAlVw8jkOVgcvb/pTJRv4ZrBYL3bzhNgVMjs aWKesfui4KhSsZkuSQnRUeJzK+ONEo7W+DZX/hn2uphao+Aw0SYhVUapZ2HcHVEqxMoG qeVQ== X-Gm-Message-State: AOAM533cubOmQB1igXsyC4T7yfLfv1221vlDg2tf/DU2IIHi7qw5hhNV +di5u4GwAGGcGCmjJLLzaBmiFMiYQcg= X-Google-Smtp-Source: ABdhPJwUc6thG/7W2v4dCyN8bZ7aWaKAT1eZ/GOTp0GpHmsAQjof5EjBrmoR7pb9D7/RqapbhRGNsQ== X-Received: by 2002:a5d:47ae:: with SMTP id 14mr15279076wrb.378.1613338140576; Sun, 14 Feb 2021 13:29:00 -0800 (PST) Received: from sblaptop.fritz.box (ipbcc1aa4b.dynamic.kabel-deutschland.de. [188.193.170.75]) by smtp.gmail.com with ESMTPSA id 13sm22041275wmj.11.2021.02.14.13.29.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 14 Feb 2021 13:29:00 -0800 (PST) From: Andreas Rheinhardt To: ffmpeg-devel@ffmpeg.org Date: Sun, 14 Feb 2021 22:28:54 +0100 Message-Id: <20210214212854.282253-1-andreas.rheinhardt@gmail.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH] avformat/utils: Fix undefined NULL + 0 X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.20 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: Andreas Rheinhardt Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" This is undefined behaviour in C, so use data = len ? data + len : data instead if data += len. GCC optimizes the branch away in this case; Clang unfortunately doesn't. Signed-off-by: Andreas Rheinhardt --- Checking for len != 0 instead of > 0 allows the compiler to optimize the branch away; maybe future versions of Clang (I used 11) will do so, too. libavformat/utils.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavformat/utils.c b/libavformat/utils.c index 3e955b85bc..cea6d4ca92 100644 --- a/libavformat/utils.c +++ b/libavformat/utils.c @@ -1426,7 +1426,7 @@ static int parse_packet(AVFormatContext *s, AVPacket *pkt, pkt->pts = pkt->dts = AV_NOPTS_VALUE; pkt->pos = -1; /* increment read pointer */ - data += len; + data = len ? data + len : data; size -= len; got_output = !!out_pkt.size;