From 64b25f5db17c3b16d2a898095a4a205404126b49 Mon Sep 17 00:00:00 2001 From: Hao Wu Date: Sun, 22 Jan 2017 10:17:52 +0800 Subject: [PATCH 1/1] FatPkg: Refine casting expression result to bigger size 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'. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu Reviewed-by: Ruiyu Ni --- 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 a6e0ec4c13..ad3c260412 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 110634508b..a92c5bff99 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 -- 2.39.2