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Michael Kubackiandmergify[bot]
0e6d10de1c
Replace traditional `#ifndef`/`#define`/`#endif` include guards with
`#pragma` once.
`#pragma once` is a widely supported preprocessor directive that
prevents header files from being included multiple times. It is
supported by all toolchains used to build edk2: GCC, Clang/LLVM, and
MSVC.
Note: Some files in BaseTools are excluded from the change if they
are autogenerated or direcly related to a header from a subproject,
etc. In particular, headers in these directories were ignored:
- BaseTools/Source/C/LzmaCompress/Sdk/
- BaseTools/Source/C/VfrCompile/Pccts/
Compared to macro-based include guards, `#pragma once`:
- Eliminates the risk of macro name collisions or copy/paste errors
where two headers inadvertently use the same guard macro.
- Eliminate inconsistency in the way include guard macros are named
(e.g., some files use `__FILE_H__`, others use `FILE_H_`, etc.).
- Reduces boilerplate (three lines replaced by one).
- Avoids polluting the macro namespace with guard symbols.
- Can improve build times as the preprocessor can skip re-opening the
file entirely, rather than re-reading it to find the matching
`#endif` ("multiple-include optimization").
- Note that some compilers may already optimize traditional include
guards, by recognzining the idiomatic pattern.
This change is made acknowledging that overall portability of the
code will technically be reduced, as `#pragma once` is not part of the
C/C++ standards.
However, this is considered acceptable given:
1. edk2 already defines a subset of supported compilers in
BaseTools/Conf/tools_def.template, all of which have supported
`#pragma once` for over two decades.
2. There have been concerns raised to the project about inconsistent
include guard naming and potential macro collisions.
Approximate compiler support dates:
- MSVC: Supported since Visual C++ 4.2 (1996)
- GCC: Supported since 3.4 (2004)
(http://gnu.ist.utl.pt/software/gcc/gcc-3.4/changes.html)
- Clang (LLVM based): Since initial release in 2007
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
76 lines
1.5 KiB
C
76 lines
1.5 KiB
C
/** @file
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Header file for helper functions useful for accessing files.
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Copyright (c) 2004 - 2018, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#pragma once
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#include <stdio.h>
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#include <stdlib.h>
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#include <Common/UefiBaseTypes.h>
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//
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// Common data structures
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//
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typedef struct {
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CHAR8 *FileImage;
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CHAR8 *Eof;
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CHAR8 *CurrentFilePointer;
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} MEMORY_FILE;
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//
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// Functions declarations
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//
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/**
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This opens a file, reads it into memory and returns a memory file
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object.
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@param InputFile Memory file image.
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@param OutputMemoryFile Handle to memory file
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@return EFI_STATUS
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OutputMemoryFile is valid if !EFI_ERROR
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**/
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EFI_STATUS
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GetMemoryFile (
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IN CHAR8 *InputFileName,
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OUT EFI_HANDLE *OutputMemoryFile
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)
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;
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/**
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Frees all memory associated with the input memory file.
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@param InputMemoryFile Handle to memory file
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@return EFI_STATUS
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**/
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EFI_STATUS
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FreeMemoryFile (
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IN EFI_HANDLE InputMemoryFile
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)
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;
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/**
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This function reads a line from the memory file. The newline characters
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are stripped and a null terminated string is returned.
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If the string pointer returned is non-NULL, then the caller must free the
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memory associated with this string.
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@param InputMemoryFile Handle to memory file
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@retval NULL if error or EOF
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@retval NULL character termincated string otherwise (MUST BE FREED BY CALLER)
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**/
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CHAR8 *
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ReadMemoryFileLine (
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IN EFI_HANDLE InputMemoryFile
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)
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;
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