[edk2-devel] [PATCH v5 1/4] MdePkg/BaseLib: Add QuickSort function on BaseLib
IanX Kuo
ianx.kuo at intel.com
Mon Oct 4 14:51:33 UTC 2021
Hi Marvin
Reply in mail
Thanks,
Ian Kuo
-----Original Message-----
From: Marvin Häuser <mhaeuser at posteo.de>
Sent: Monday, October 4, 2021 8:56 PM
To: devel at edk2.groups.io; Kuo, IanX <ianx.kuo at intel.com>
Cc: Chan, Amy <amy.chan at intel.com>; Ni, Ray <ray.ni at intel.com>; Kinney, Michael D <michael.d.kinney at intel.com>; Liming Gao <gaoliming at byosoft.com.cn>; Liu, Zhiguang <zhiguang.liu at intel.com>
Subject: Re: [edk2-devel] [PATCH v5 1/4] MdePkg/BaseLib: Add QuickSort function on BaseLib
Good day IanX,
On 04/10/2021 07:03, IanX Kuo wrote:
> From: IanX Kuo <ianx.kuo at intel.com>
>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3675
>
> Add QuickSort function into BaseLib
>
> Cc: Ray Ni <ray.ni at intel.com>
> Cc: Michael D Kinney <michael.d.kinney at intel.com>
> Cc: Liming Gao <gaoliming at byosoft.com.cn>
> Cc: Zhiguang Liu <zhiguang.liu at intel.com>
> Signed-off-by: IanX Kuo <ianx.kuo at intel.com>
> ---
> MdePkg/Include/Library/BaseLib.h | 49 ++++++++
> MdePkg/Library/BaseLib/BaseLib.inf | 1 +
> MdePkg/Library/BaseLib/QuickSort.c | 117 ++++++++++++++++++
> .../Library/BaseLib/UnitTestHostBaseLib.inf | 3 +-
> 4 files changed, 169 insertions(+), 1 deletion(-)
> create mode 100644 MdePkg/Library/BaseLib/QuickSort.c
>
> diff --git a/MdePkg/Include/Library/BaseLib.h
> b/MdePkg/Include/Library/BaseLib.h
> index 2452c1d92e..2423169be4 100644
> --- a/MdePkg/Include/Library/BaseLib.h
> +++ b/MdePkg/Include/Library/BaseLib.h
> @@ -13,6 +13,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
>
> #ifndef __BASE_LIB__
> #define __BASE_LIB__
> +#include <Uefi/UefiBaseType.h>
Accidental change?
Ian: No, Without it, it won't find type "EFI_STATUS" and will cause build error. Origin return type is "VOID" on function "VOID QuickSortWorker".
And my change "EFI_STATUS QuickSort", so "EFI_STATUS" depends on "UefiBaseType.h"
>
> //
> // Definitions for architecture-specific types @@ -2856,6 +2857,54
> @@ RemoveEntryList (
> //
> // Math Services
> //
> +/**
> + Prototype for comparison function for any two element types.
> +
> + @param[in] Buffer1 The pointer to first buffer.
> + @param[in] Buffer2 The pointer to second buffer.
> +
> + @retval 0 Buffer1 equal to Buffer2.
> + @return <0 Buffer1 is less than Buffer2.
> + @return >0 Buffer1 is greater than Buffer2.
> +**/
> +typedef
> +INTN
> +(EFIAPI *BASE_SORT_COMPARE)(
> + IN CONST VOID *Buffer1,
> + IN CONST VOID *Buffer2
> + );
> +
> +/**
> + Worker function for QuickSorting.
"Worker" functions are usually private.
Ian: Thank for reply, will remove "Worker" in my next patch.
> This function is identical to perform QuickSort,
> + except that is uses the pre-allocated buffer so the in place
> + sorting does not need to allocate and free buffers constantly.
> +
> + Each element must be equal sized.
> +
> + if Count is < 2 then perform no action.
This follows directly from the definition of sorting.
> + if Size is < 1 then perform no action.
It would be perfectly valid to ASSERT on this in my opinion, so I would not hardcode the behaviour in the function spec.
> +
> + @param[in, out] BufferToSort on call a Buffer of (possibly sorted) elements
> + on return a buffer of sorted elements
> + @param[in] Count the number of elements in the buffer to sort
> + @param[in] ElementSize Size of an element in bytes
> + @param[in] CompareFunction The function to call to perform the comparison
> + of any 2 elements
> + @param [in] BufferOneElement Caller provided buffer whose size equals to ElementSize.
> + It's used by QuickSort() for swapping in sorting.
This is out, not in. Maybe add a note its content is undefined on return?
Ian: Got it, will change parameter type from "[in]" to "[out]" in my next patch.
> +
> + @retval EFI_SUCCESS The quick sort is finished.
> + @retval EFI_INVALID_PARAMETER When BufferToSort is NULL,
> + CompareFunction is NULL or Buffer is NULL
These constraints are all caller constraints and not constraints on e.g.
untrusted, external data. Hence, in my opinion it is perfectly valid to ASSERT them rather than runtime-check and emit status codes. This would mean the function could return VOID, there'd be no need to check status codes, and there'd be no need to worry about intermediate states (e.g.
what is the content of BufferToSort when an error is returned?).
Ian: Got it, will change return type from "EFI_STATUS" to "VOID" in my next patch.
> +**/
> +EFI_STATUS
> +EFIAPI
> +QuickSort (
> + IN OUT VOID *BufferToSort,
> + IN CONST UINTN Count,
> + IN CONST UINTN ElementSize,
> + IN BASE_SORT_COMPARE CompareFunction,
> + IN VOID *BufferOneElement
This is OUT, not IN.
Ian: Got it, will change it in my next patch.
> + );
>
> /**
> Shifts a 64-bit integer left between 0 and 63 bits. The low bits
> are filled diff --git a/MdePkg/Library/BaseLib/BaseLib.inf
> b/MdePkg/Library/BaseLib/BaseLib.inf
> index 6efa5315b6..cebda3b210 100644
> --- a/MdePkg/Library/BaseLib/BaseLib.inf
> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> @@ -32,6 +32,7 @@
> SwapBytes16.c
> LongJump.c
> SetJump.c
> + QuickSort.c
> RShiftU64.c
> RRotU64.c
> RRotU32.c
> diff --git a/MdePkg/Library/BaseLib/QuickSort.c
> b/MdePkg/Library/BaseLib/QuickSort.c
> new file mode 100644
> index 0000000000..f95af9e238
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/QuickSort.c
> @@ -0,0 +1,117 @@
> +/** @file
> + Math worker functions.
> +
> + Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
> + SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "BaseLibInternals.h"
> +#include <Uefi/UefiBaseType.h>
Is the second include not implied by the first?
Ian: If we change QuickSort return type from "EFI_STATUS" to "VOID", the include can be removed.
> +
> +/**
> + Worker function for QuickSorting. This function is identical to
> +perform QuickSort,
> + except that is uses the pre-allocated buffer so the in place
> +sorting does not need to
> + allocate and free buffers constantly.
> +
> + Each element must be equal sized.
> +
> + if Count is < 2 then perform no action.
> + if Size is < 1 then perform no action.
> +
> + @param[in, out] BufferToSort on call a Buffer of (possibly sorted) elements
> + on return a buffer of sorted elements
> + @param[in] Count the number of elements in the buffer to sort
> + @param[in] ElementSize Size of an element in bytes
> + @param[in] CompareFunction The function to call to perform the comparison
> + of any 2 elements
> + @param [in] BufferOneElement Caller provided buffer whose size equals to ElementSize.
> + It's used by QuickSort() for swapping in sorting.
> +
> + @retval EFI_SUCCESS The quick sort is finished.
> + @retval EFI_INVALID_PARAMETER When BufferToSort is NULL,
> + CompareFunction is NULL, or BufferOneElement is NULL
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +QuickSort (
> + IN OUT VOID *BufferToSort,
> + IN CONST UINTN Count,
> + IN CONST UINTN ElementSize,
> + IN BASE_SORT_COMPARE CompareFunction,
> + IN VOID *BufferOneElement
> + )
> +{
> + VOID *Pivot;
> + UINTN LoopCount;
> + UINTN NextSwapLocation;
> +
> + if ((BufferToSort == NULL) || (CompareFunction == NULL) || (BufferOneElement == NULL)) {
> + return EFI_INVALID_PARAMETER;
> + }
> +
> + if (Count < 2 || ElementSize < 1) {
> + return EFI_SUCCESS;
> + }
> +
> + NextSwapLocation = 0;
> +
> + //
> + // pick a pivot (we choose last element) // Pivot = ((UINT8*)
> + BufferToSort + ((Count - 1) * ElementSize));
> +
> + //
> + // Now get the pivot such that all on "left" are below it // and
> + everything "right" are above it // for (LoopCount = 0; LoopCount <
> + Count -1; LoopCount++) {
> + //
> + // if the element is less than the pivot
> + //
> + if (CompareFunction ((VOID*) ((UINT8*) BufferToSort +
> + ((LoopCount) * ElementSize)), Pivot) <= 0){
Comment mismatches logic, logic swaps on equality too.
Best regards,
Marvin
> + //
> + // swap
> + //
> + CopyMem (BufferOneElement, (UINT8*) BufferToSort + (NextSwapLocation * ElementSize), ElementSize);
> + CopyMem ((UINT8*) BufferToSort + (NextSwapLocation * ElementSize), (UINT8*) BufferToSort + ((LoopCount) * ElementSize), ElementSize);
> + CopyMem ((UINT8*) BufferToSort + ((LoopCount)*ElementSize),
> + BufferOneElement, ElementSize);
> +
> + //
> + // increment NextSwapLocation
> + //
> + NextSwapLocation++;
> + }
> + }
> + //
> + // swap pivot to it's final position (NextSwapLocation) //
> + CopyMem (BufferOneElement, Pivot, ElementSize); CopyMem (Pivot,
> + (UINT8*) BufferToSort + (NextSwapLocation * ElementSize),
> + ElementSize); CopyMem ((UINT8*) BufferToSort + (NextSwapLocation *
> + ElementSize), BufferOneElement, ElementSize);
> +
> + //
> + // Now recurse on 2 partial lists. neither of these will have the
> + 'pivot' element // IE list is sorted left half, pivot element, sorted right half...
> + //
> + if (NextSwapLocation >= 2) {
> + QuickSort (
> + BufferToSort,
> + NextSwapLocation,
> + ElementSize,
> + CompareFunction,
> + BufferOneElement
> + );
> + }
> +
> + if ((Count - NextSwapLocation - 1) >= 2) {
> + QuickSort (
> + (UINT8 *)BufferToSort + (NextSwapLocation + 1) * ElementSize,
> + Count - NextSwapLocation - 1,
> + ElementSize,
> + CompareFunction,
> + BufferOneElement
> + );
> + }
> + return EFI_SUCCESS;
> +}
> diff --git a/MdePkg/Library/BaseLib/UnitTestHostBaseLib.inf
> b/MdePkg/Library/BaseLib/UnitTestHostBaseLib.inf
> index eae1a7158d..d09bd12bef 100644
> --- a/MdePkg/Library/BaseLib/UnitTestHostBaseLib.inf
> +++ b/MdePkg/Library/BaseLib/UnitTestHostBaseLib.inf
> @@ -1,7 +1,7 @@
> ## @file
> # Base Library implementation for use with host based unit tests.
> #
> -# Copyright (c) 2007 - 2020, Intel Corporation. All rights
> reserved.<BR>
> +# Copyright (c) 2007 - 2021, Intel Corporation. All rights
> +reserved.<BR>
> # Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
> # Portions copyright (c) 2011 - 2013, ARM Ltd. All rights reserved.<BR>
> # Copyright (c) 2020, Hewlett Packard Enterprise Development LP.
> All rights reserved.<BR> @@ -33,6 +33,7 @@
> SwapBytes16.c
> LongJump.c
> SetJump.c
> + QuickSort.c
> RShiftU64.c
> RRotU64.c
> RRotU32.c
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#81450): https://edk2.groups.io/g/devel/message/81450
Mute This Topic: https://groups.io/mt/86059847/1813853
Group Owner: devel+owner at edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [edk2-devel-archive at redhat.com]
-=-=-=-=-=-=-=-=-=-=-=-
More information about the edk2-devel-archive
mailing list