From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 5BD4282151 for ; Fri, 24 Feb 2017 21:12:54 -0800 (PST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Feb 2017 21:12:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,202,1484035200"; d="scan'208";a="52624013" Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by orsmga002.jf.intel.com with ESMTP; 24 Feb 2017 21:12:53 -0800 From: Hao Wu To: edk2-devel@lists.01.org Cc: Hao Wu , Ruiyu Ni Date: Sat, 25 Feb 2017 13:12:26 +0800 Message-Id: <1487999555-9764-4-git-send-email-hao.a.wu@intel.com> X-Mailer: git-send-email 1.9.5.msysgit.0 In-Reply-To: <1487999555-9764-1-git-send-email-hao.a.wu@intel.com> References: <1487999555-9764-1-git-send-email-hao.a.wu@intel.com> Subject: [PATCH v3 03/12] FatPkg: Refine casting expression result to bigger size X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 Feb 2017 05:12:54 -0000 There are cases that the operands of an expression are all with rank less than UINT64/INT64 and the result of the expression is explicitly cast to UINT64/INT64 to fit the target size. An example will be: UINT32 a,b; // a and b can be any unsigned int type with rank less than UINT64, like // UINT8, UINT16, etc. UINT64 c; c = (UINT64) (a + b); Some static code checkers may warn that the expression result might overflow within the rank of "int" (integer promotions) and the result is then cast to a bigger size. The commit refines codes by the following rules: 1). When the expression is possible to overflow the range of unsigned int/ int: c = (UINT64)a + b; 2). When the expression will not overflow within the rank of "int", remove the explicit type casts: c = a + b; 3). When the expression will be cast to pointer of possible greater size: UINT32 a,b; VOID *c; c = (VOID *)(UINTN)(a + b); --> c = (VOID *)((UINTN)a + b); 4). When one side of a comparison expression contains only operands with rank less than UINT32: UINT8 a; UINT16 b; UINTN c; if ((UINTN)(a + b) > c) {...} --> if (((UINT32)a + b) > c) {...} For rule 4), if we remove the 'UINTN' type cast like: if (a + b > c) {...} The VS compiler will complain with warning C4018 (signed/unsigned mismatch, level 3 warning) due to promoting 'a + b' to type 'int'. Cc: Ruiyu Ni Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu --- FatPkg/EnhancedFatDxe/ReadWrite.c | 4 ++-- FatPkg/FatPei/FatLiteAccess.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/FatPkg/EnhancedFatDxe/ReadWrite.c b/FatPkg/EnhancedFatDxe/ReadWrite.c index a6e0ec4..ad3c260 100644 --- a/FatPkg/EnhancedFatDxe/ReadWrite.c +++ b/FatPkg/EnhancedFatDxe/ReadWrite.c @@ -1,7 +1,7 @@ /** @file Functions that perform file read/write. -Copyright (c) 2005 - 2015, Intel Corporation. All rights reserved.
+Copyright (c) 2005 - 2017, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this distribution. The full text of the license may be found at @@ -173,7 +173,7 @@ Done: // Update IFile->Position, if everything is all right // CurrentPos = ODir->CurrentPos; - IFile->Position = (UINT64) (CurrentPos * sizeof (FAT_DIRECTORY_ENTRY)); + IFile->Position = CurrentPos * sizeof (FAT_DIRECTORY_ENTRY); } return Status; diff --git a/FatPkg/FatPei/FatLiteAccess.c b/FatPkg/FatPei/FatLiteAccess.c index 1106345..a92c5bf 100644 --- a/FatPkg/FatPei/FatLiteAccess.c +++ b/FatPkg/FatPei/FatLiteAccess.c @@ -1,7 +1,7 @@ /** @file FAT file system access routines for FAT recovery PEIM -Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this @@ -393,7 +393,7 @@ FatReadFile ( } else { if ((File->Attributes & FAT_ATTR_DIRECTORY) == 0) { - Size = Size < (File->FileSize - File->CurrentPos) ? Size : (UINTN) (File->FileSize - File->CurrentPos); + Size = Size < (File->FileSize - File->CurrentPos) ? Size : (File->FileSize - File->CurrentPos); } // // This is a normal cluster based file -- 1.9.5.msysgit.0