summaryrefslogtreecommitdiffstats
path: root/FatPkg/FatPei
diff options
context:
space:
mode:
authorHao Wu <hao.a.wu@intel.com>2017-01-22 10:17:52 +0800
committerHao Wu <hao.a.wu@intel.com>2017-03-06 14:33:21 +0800
commit64b25f5db17c3b16d2a898095a4a205404126b49 (patch)
tree0474682709cb94e92dda407f08dbb9d7614e1997 /FatPkg/FatPei
parent16f6922709952c7ad468dcdee6ef94b3e5a3cd90 (diff)
downloadedk2-64b25f5db17c3b16d2a898095a4a205404126b49.tar.gz
edk2-64b25f5db17c3b16d2a898095a4a205404126b49.tar.bz2
edk2-64b25f5db17c3b16d2a898095a4a205404126b49.zip
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 <hao.a.wu@intel.com> Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Diffstat (limited to 'FatPkg/FatPei')
-rw-r--r--FatPkg/FatPei/FatLiteAccess.c4
1 files changed, 2 insertions, 2 deletions
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.<BR>
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
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