diff options
Diffstat (limited to 'ShellPkg/Library/BaseSortLib/BaseSortLib.c')
| -rw-r--r-- | ShellPkg/Library/BaseSortLib/BaseSortLib.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/ShellPkg/Library/BaseSortLib/BaseSortLib.c b/ShellPkg/Library/BaseSortLib/BaseSortLib.c new file mode 100644 index 0000000..04d818e --- /dev/null +++ b/ShellPkg/Library/BaseSortLib/BaseSortLib.c @@ -0,0 +1,170 @@ +/** @file
+ Library used for sorting routines.
+
+Copyright (c) 2009, 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
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Uefi.h>
+
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/SortLib.h>
+
+/**
+ Worker function for QuickSorting. This function is identical to PerformQuickSort,
+ 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 BufferToSort is NULL, then ASSERT.
+ if CompareFunction is NULL, then ASSERT.
+ if Buffer is NULL, then ASSERT.
+
+ 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] Buffer Buffer of size ElementSize for use in swapping
+**/
+VOID
+EFIAPI
+QuickSortWorker (
+ IN OUT VOID *BufferToSort,
+ IN CONST UINTN Count,
+ IN CONST UINTN ElementSize,
+ IN SORT_COMPARE CompareFunction,
+ IN VOID *Buffer
+ ){
+ VOID *Pivot;
+ UINTN LoopCount;
+ UINTN NextSwapLocation;
+
+ ASSERT(BufferToSort != NULL);
+ ASSERT(CompareFunction != NULL);
+ ASSERT(Buffer != NULL);
+
+ if ( Count < 2
+ || ElementSize < 1
+ ){
+ return;
+ }
+
+ 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){
+ //
+ // swap
+ //
+ CopyMem (Buffer, (UINT8*)BufferToSort+(NextSwapLocation*ElementSize), ElementSize);
+ CopyMem ((UINT8*)BufferToSort+(NextSwapLocation*ElementSize), (UINT8*)BufferToSort+((LoopCount)*ElementSize), ElementSize);
+ CopyMem ((UINT8*)BufferToSort+((LoopCount)*ElementSize), Buffer, ElementSize);
+
+ //
+ // increment NextSwapLocation
+ //
+ NextSwapLocation++;
+ }
+ }
+ //
+ // swap pivot to it's final position (NextSwapLocaiton)
+ //
+ CopyMem (Buffer, Pivot, ElementSize);
+ CopyMem (Pivot, (UINT8*)BufferToSort+(NextSwapLocation*ElementSize), ElementSize);
+ CopyMem ((UINT8*)BufferToSort+(NextSwapLocation*ElementSize), Buffer, ElementSize);
+
+ //
+ // Now recurse on 2 paritial lists. neither of these will have the 'pivot' element
+ // IE list is sorted left half, pivot element, sorted right half...
+ //
+ QuickSortWorker(
+ BufferToSort,
+ NextSwapLocation,
+ ElementSize,
+ CompareFunction,
+ Buffer);
+
+ QuickSortWorker(
+ (UINT8 *)BufferToSort + (NextSwapLocation+1) * ElementSize,
+ Count - NextSwapLocation - 1,
+ ElementSize,
+ CompareFunction,
+ Buffer);
+
+ return;
+}
+/**
+ Function to perform a Quick Sort alogrithm on a buffer of comparable elements.
+
+ Each element must be equal sized.
+
+ if BufferToSort is NULL, then ASSERT.
+ if CompareFunction is NULL, then ASSERT.
+
+ 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
+**/
+VOID
+EFIAPI
+PerformQuickSort (
+ IN OUT VOID *BufferToSort,
+ IN CONST UINTN Count,
+ IN CONST UINTN ElementSize,
+ IN SORT_COMPARE CompareFunction
+ ){
+ VOID *Buffer;
+
+ ASSERT(BufferToSort != NULL);
+ ASSERT(CompareFunction != NULL);
+
+ Buffer = AllocatePool(ElementSize);
+ ASSERT(Buffer != NULL);
+
+ QuickSortWorker(
+ BufferToSort,
+ Count,
+ ElementSize,
+ CompareFunction,
+ Buffer);
+
+ FreePool(Buffer);
+ return;
+}
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