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https://github.com/reactos/reactos.git
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957 lines
25 KiB
C
957 lines
25 KiB
C
/*
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* PROJECT: ReactOS system libraries
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* LICENSE: GNU GPL - See COPYING in the top level directory
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* BSD - See COPYING.ARM in the top level directory
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* FILE: lib/rtl/bitmap.c
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* PURPOSE: Bitmap functions
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* PROGRAMMER: Timo Kreuzer (timo.kreuzer@reactos.org)
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*/
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/* INCLUDES *****************************************************************/
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#include <rtl.h>
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#define NDEBUG
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#include <debug.h>
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// FIXME: hack
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#undef ASSERT
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#define ASSERT(...)
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#ifdef USE_RTL_BITMAP64
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#define _BITCOUNT 64
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#define MAXINDEX 0xFFFFFFFFFFFFFFFF
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typedef ULONG64 BITMAP_INDEX, *PBITMAP_INDEX;
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typedef ULONG64 BITMAP_BUFFER, *PBITMAP_BUFFER;
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#define RTL_BITMAP RTL_BITMAP64
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#define PRTL_BITMAP PRTL_BITMAP64
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#define RTL_BITMAP_RUN RTL_BITMAP_RUN64
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#define PRTL_BITMAP_RUN PRTL_BITMAP_RUN64
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#undef BitScanForward
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#define BitScanForward(Index, Mask) \
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do { unsigned long tmp; BitScanForward64(&tmp, Mask); *Index = tmp; } while (0)
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#undef BitScanReverse
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#define BitScanReverse(Index, Mask) \
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do { unsigned long tmp; BitScanReverse64(&tmp, Mask); *Index = tmp; } while (0)
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#define RtlFillMemoryUlong RtlFillMemoryUlonglong
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#define RtlInitializeBitMap RtlInitializeBitMap64
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#define RtlClearAllBits RtlClearAllBits64
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#define RtlSetAllBits RtlSetAllBits64
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#define RtlClearBit RtlClearBit64
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#define RtlSetBit RtlSetBit64
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#define RtlClearBits RtlClearBits64
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#define RtlSetBits RtlSetBits64
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#define RtlTestBit RtlTestBit64
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#define RtlAreBitsClear RtlAreBitsClear64
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#define RtlAreBitsSet RtlAreBitsSet64
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#define RtlNumberOfSetBits RtlNumberOfSetBits64
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#define RtlNumberOfClearBits RtlNumberOfClearBits64
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#define RtlFindClearBits RtlFindClearBits64
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#define RtlFindSetBits RtlFindSetBits64
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#define RtlFindClearBitsAndSet RtlFindClearBitsAndSet64
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#define RtlFindSetBitsAndClear RtlFindSetBitsAndClear64
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#define RtlFindNextForwardRunClear RtlFindNextForwardRunClear64
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#define RtlFindNextForwardRunSet RtlFindNextForwardRunSet64
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#define RtlFindFirstRunClear RtlFindFirstRunClear64
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#define RtlFindLastBackwardRunClear RtlFindLastBackwardRunClear64
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#define RtlFindClearRuns RtlFindClearRuns64
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#define RtlFindLongestRunClear RtlFindLongestRunClear64
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#define RtlFindLongestRunSet RtlFindLongestRunSet64
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#else
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#define _BITCOUNT 32
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#define MAXINDEX 0xFFFFFFFF
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typedef ULONG BITMAP_INDEX, *PBITMAP_INDEX;
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typedef ULONG BITMAP_BUFFER, *PBITMAP_BUFFER;
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#endif
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/* DATA *********************************************************************/
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/* Number of set bits per byte value */
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static const
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UCHAR
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BitCountTable[256] =
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{
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/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
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0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, /* 0x */
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, /* 1x */
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, /* 2x */
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* 3x */
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, /* 4x */
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* 5x */
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* 6c */
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, /* 7x */
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, /* 8x */
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* 9x */
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* Ax */
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, /* Bx */
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* Cx */
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, /* Dx */
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, /* Ex */
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4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 /* Fx */
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};
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/* PRIVATE FUNCTIONS ********************************************************/
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static __inline
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BITMAP_INDEX
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RtlpGetLengthOfRunClear(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_ BITMAP_INDEX StartingIndex,
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_In_ BITMAP_INDEX MaxLength)
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{
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BITMAP_INDEX Value, BitPos, Length;
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PBITMAP_BUFFER Buffer, MaxBuffer;
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/* If we are already at the end, the length of the run is zero */
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ASSERT(StartingIndex <= BitMapHeader->SizeOfBitMap);
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if (StartingIndex >= BitMapHeader->SizeOfBitMap)
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return 0;
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/* Calculate positions */
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Buffer = BitMapHeader->Buffer + StartingIndex / _BITCOUNT;
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BitPos = StartingIndex & (_BITCOUNT - 1);
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/* Calculate the maximum length */
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MaxLength = min(MaxLength, BitMapHeader->SizeOfBitMap - StartingIndex);
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MaxBuffer = Buffer + (BitPos + MaxLength + _BITCOUNT - 1) / _BITCOUNT;
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/* Clear the bits that don't belong to this run */
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Value = *Buffer++ >> BitPos << BitPos;
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/* Skip all clear ULONGs */
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while (Value == 0 && Buffer < MaxBuffer)
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{
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Value = *Buffer++;
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}
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/* Did we reach the end? */
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if (Value == 0)
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{
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/* Return maximum length */
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return MaxLength;
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}
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/* We hit a set bit, check how many clear bits are left */
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BitScanForward(&BitPos, Value);
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/* Calculate length up to where we read */
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Length = (BITMAP_INDEX)(Buffer - BitMapHeader->Buffer) * _BITCOUNT - StartingIndex;
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Length += BitPos - _BITCOUNT;
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/* Make sure we don't go past the last bit */
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if (Length > BitMapHeader->SizeOfBitMap - StartingIndex)
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Length = BitMapHeader->SizeOfBitMap - StartingIndex;
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/* Return the result */
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return Length;
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}
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static __inline
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BITMAP_INDEX
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RtlpGetLengthOfRunSet(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_ BITMAP_INDEX StartingIndex,
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_In_ BITMAP_INDEX MaxLength)
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{
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BITMAP_INDEX InvValue, BitPos, Length;
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PBITMAP_BUFFER Buffer, MaxBuffer;
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/* If we are already at the end, the length of the run is zero */
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ASSERT(StartingIndex <= BitMapHeader->SizeOfBitMap);
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if (StartingIndex >= BitMapHeader->SizeOfBitMap)
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return 0;
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/* Calculate positions */
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Buffer = BitMapHeader->Buffer + StartingIndex / _BITCOUNT;
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BitPos = StartingIndex & (_BITCOUNT - 1);
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/* Calculate the maximum length */
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MaxLength = min(MaxLength, BitMapHeader->SizeOfBitMap - StartingIndex);
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MaxBuffer = Buffer + (BitPos + MaxLength + _BITCOUNT - 1) / _BITCOUNT;
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/* Get the inversed value, clear bits that don't belong to the run */
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InvValue = ~(*Buffer++) >> BitPos << BitPos;
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/* Skip all set ULONGs */
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while (InvValue == 0 && Buffer < MaxBuffer)
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{
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InvValue = ~(*Buffer++);
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}
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/* Did we reach the end? */
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if (InvValue == 0)
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{
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/* Yes, return maximum */
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return MaxLength;
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}
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/* We hit a clear bit, check how many set bits are left */
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BitScanForward(&BitPos, InvValue);
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/* Calculate length up to where we read */
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Length = (ULONG)(Buffer - BitMapHeader->Buffer) * _BITCOUNT - StartingIndex;
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Length += BitPos - _BITCOUNT;
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/* Make sure we don't go past the last bit */
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if (Length > BitMapHeader->SizeOfBitMap - StartingIndex)
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Length = BitMapHeader->SizeOfBitMap - StartingIndex;
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/* Return the result */
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return Length;
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}
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/* PUBLIC FUNCTIONS **********************************************************/
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#ifndef USE_RTL_BITMAP64
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CCHAR
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NTAPI
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RtlFindMostSignificantBit(ULONGLONG Value)
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{
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ULONG Position;
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#ifdef _M_AMD64
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if (BitScanReverse64(&Position, Value))
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{
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return (CCHAR)Position;
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}
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#else
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if (BitScanReverse(&Position, Value >> _BITCOUNT))
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{
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return (CCHAR)(Position + _BITCOUNT);
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}
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else if (BitScanReverse(&Position, (ULONG)Value))
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{
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return (CCHAR)Position;
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}
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#endif
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return -1;
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}
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CCHAR
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NTAPI
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RtlFindLeastSignificantBit(ULONGLONG Value)
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{
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ULONG Position;
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#ifdef _M_AMD64
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if (BitScanForward64(&Position, Value))
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{
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return (CCHAR)Position;
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}
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#else
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if (BitScanForward(&Position, (ULONG)Value))
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{
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return (CCHAR)Position;
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}
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else if (BitScanForward(&Position, Value >> _BITCOUNT))
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{
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return (CCHAR)(Position + _BITCOUNT);
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}
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#endif
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return -1;
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}
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#endif /* !USE_RTL_BITMAP64 */
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VOID
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NTAPI
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RtlInitializeBitMap(
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_Out_ PRTL_BITMAP BitMapHeader,
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_In_opt_ __drv_aliasesMem PBITMAP_BUFFER BitMapBuffer,
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_In_opt_ ULONG SizeOfBitMap)
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{
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/* Setup the bitmap header */
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BitMapHeader->SizeOfBitMap = SizeOfBitMap;
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BitMapHeader->Buffer = BitMapBuffer;
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}
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VOID
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NTAPI
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RtlClearAllBits(
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_In_ PRTL_BITMAP BitMapHeader)
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{
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BITMAP_INDEX LengthInUlongs;
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LengthInUlongs = (BitMapHeader->SizeOfBitMap + _BITCOUNT - 1) / _BITCOUNT;
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RtlFillMemoryUlong(BitMapHeader->Buffer, LengthInUlongs * sizeof(BITMAP_INDEX), 0);
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}
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VOID
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NTAPI
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RtlSetAllBits(
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_In_ PRTL_BITMAP BitMapHeader)
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{
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BITMAP_INDEX LengthInUlongs;
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LengthInUlongs = (BitMapHeader->SizeOfBitMap + _BITCOUNT - 1) / _BITCOUNT;
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RtlFillMemoryUlong(BitMapHeader->Buffer, LengthInUlongs * sizeof(BITMAP_INDEX), ~0);
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}
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VOID
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NTAPI
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RtlClearBit(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_ BITMAP_INDEX BitNumber)
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{
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ASSERT(BitNumber <= BitMapHeader->SizeOfBitMap);
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BitMapHeader->Buffer[BitNumber / _BITCOUNT] &= ~(1 << (BitNumber & (_BITCOUNT - 1)));
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}
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VOID
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NTAPI
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RtlSetBit(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_range_(<, BitMapHeader->SizeOfBitMap) BITMAP_INDEX BitNumber)
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{
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ASSERT(BitNumber <= BitMapHeader->SizeOfBitMap);
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BitMapHeader->Buffer[BitNumber / _BITCOUNT] |= ((BITMAP_INDEX)1 << (BitNumber & (_BITCOUNT - 1)));
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}
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VOID
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NTAPI
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RtlClearBits(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_range_(0, BitMapHeader->SizeOfBitMap - NumberToClear) BITMAP_INDEX StartingIndex,
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_In_range_(0, BitMapHeader->SizeOfBitMap - StartingIndex) BITMAP_INDEX NumberToClear)
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{
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BITMAP_INDEX Bits, Mask;
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PBITMAP_BUFFER Buffer;
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ASSERT(StartingIndex + NumberToClear <= BitMapHeader->SizeOfBitMap);
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/* Calculate buffer start and first bit index */
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Buffer = &BitMapHeader->Buffer[StartingIndex / _BITCOUNT];
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Bits = StartingIndex & (_BITCOUNT - 1);
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/* Are we unaligned? */
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if (Bits)
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{
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/* Create an inverse mask by shifting MAXINDEX */
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Mask = MAXINDEX << Bits;
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/* This is what's left in the first ULONG */
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Bits = _BITCOUNT - Bits;
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/* Even less bits to clear? */
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if (NumberToClear < Bits)
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{
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/* Calculate how many bits are left */
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Bits -= NumberToClear;
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/* Fixup the mask on the high side */
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Mask = Mask << Bits >> Bits;
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/* Clear bits and return */
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*Buffer &= ~Mask;
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return;
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}
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/* Clear bits */
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*Buffer &= ~Mask;
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/* Update buffer and left bits */
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Buffer++;
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NumberToClear -= Bits;
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}
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/* Clear all full ULONGs */
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RtlFillMemoryUlong(Buffer, NumberToClear >> 3, 0);
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Buffer += NumberToClear / _BITCOUNT;
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/* Clear what's left */
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NumberToClear &= (_BITCOUNT - 1);
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if (NumberToClear != 0)
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{
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Mask = MAXINDEX << NumberToClear;
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*Buffer &= Mask;
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}
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}
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VOID
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NTAPI
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RtlSetBits(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_range_(0, BitMapHeader->SizeOfBitMap - NumberToSet) BITMAP_INDEX StartingIndex,
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_In_range_(0, BitMapHeader->SizeOfBitMap - StartingIndex) BITMAP_INDEX NumberToSet)
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{
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BITMAP_INDEX Bits, Mask;
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PBITMAP_BUFFER Buffer;
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ASSERT(StartingIndex + NumberToSet <= BitMapHeader->SizeOfBitMap);
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/* Calculate buffer start and first bit index */
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Buffer = &BitMapHeader->Buffer[StartingIndex / _BITCOUNT];
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Bits = StartingIndex & (_BITCOUNT - 1);
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/* Are we unaligned? */
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if (Bits)
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{
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/* Create a mask by shifting MAXINDEX */
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Mask = MAXINDEX << Bits;
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/* This is what's left in the first ULONG */
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Bits = _BITCOUNT - Bits;
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/* Even less bits to clear? */
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if (NumberToSet < Bits)
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{
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/* Calculate how many bits are left */
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Bits -= NumberToSet;
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/* Fixup the mask on the high side */
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Mask = Mask << Bits >> Bits;
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/* Set bits and return */
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*Buffer |= Mask;
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return;
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}
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/* Set bits */
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*Buffer |= Mask;
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/* Update buffer and left bits */
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Buffer++;
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NumberToSet -= Bits;
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}
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/* Set all full ULONGs */
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RtlFillMemoryUlong(Buffer, NumberToSet >> 3, MAXINDEX);
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Buffer += NumberToSet / _BITCOUNT;
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/* Set what's left */
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NumberToSet &= (_BITCOUNT - 1);
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if (NumberToSet != 0)
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{
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Mask = MAXINDEX << NumberToSet;
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*Buffer |= ~Mask;
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}
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}
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BOOLEAN
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NTAPI
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RtlTestBit(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_range_(<, BitMapHeader->SizeOfBitMap) BITMAP_INDEX BitNumber)
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{
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ASSERT(BitNumber < BitMapHeader->SizeOfBitMap);
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return (BitMapHeader->Buffer[BitNumber / _BITCOUNT] >> (BitNumber & (_BITCOUNT - 1))) & 1;
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}
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BOOLEAN
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NTAPI
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RtlAreBitsClear(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_ BITMAP_INDEX StartingIndex,
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_In_ BITMAP_INDEX Length)
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{
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/* Verify parameters */
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if ((StartingIndex + Length > BitMapHeader->SizeOfBitMap) ||
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(StartingIndex + Length <= StartingIndex))
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return FALSE;
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return RtlpGetLengthOfRunClear(BitMapHeader, StartingIndex, Length) >= Length;
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}
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BOOLEAN
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NTAPI
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RtlAreBitsSet(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_ BITMAP_INDEX StartingIndex,
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_In_ BITMAP_INDEX Length)
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{
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/* Verify parameters */
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if ((StartingIndex + Length > BitMapHeader->SizeOfBitMap) ||
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(StartingIndex + Length <= StartingIndex))
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return FALSE;
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return RtlpGetLengthOfRunSet(BitMapHeader, StartingIndex, Length) >= Length;
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}
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BITMAP_INDEX
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NTAPI
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RtlNumberOfSetBits(
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_In_ PRTL_BITMAP BitMapHeader)
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{
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PUCHAR Byte, MaxByte;
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BITMAP_INDEX BitCount = 0;
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ULONG Shift;
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Byte = (PUCHAR)BitMapHeader->Buffer;
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MaxByte = Byte + BitMapHeader->SizeOfBitMap / 8;
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while (Byte < MaxByte)
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{
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BitCount += BitCountTable[*Byte++];
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}
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if (BitMapHeader->SizeOfBitMap & 7)
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{
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Shift = 8 - (BitMapHeader->SizeOfBitMap & 7);
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BitCount += BitCountTable[((*Byte) << Shift) & 0xFF];
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}
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return BitCount;
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}
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BITMAP_INDEX
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NTAPI
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RtlNumberOfClearBits(
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_In_ PRTL_BITMAP BitMapHeader)
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{
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/* Do some math */
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return BitMapHeader->SizeOfBitMap - RtlNumberOfSetBits(BitMapHeader);
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}
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BITMAP_INDEX
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NTAPI
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RtlFindClearBits(
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_In_ PRTL_BITMAP BitMapHeader,
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_In_ BITMAP_INDEX NumberToFind,
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_In_ BITMAP_INDEX HintIndex)
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{
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BITMAP_INDEX CurrentBit, Margin, CurrentLength;
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/* Check for valid parameters */
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if (!BitMapHeader || NumberToFind > BitMapHeader->SizeOfBitMap)
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|
{
|
|
return MAXINDEX;
|
|
}
|
|
|
|
/* Check if the hint is outside the bitmap */
|
|
if (HintIndex >= BitMapHeader->SizeOfBitMap) HintIndex = 0;
|
|
|
|
/* Check for trivial case */
|
|
if (NumberToFind == 0)
|
|
{
|
|
/* Return hint rounded down to byte margin */
|
|
return HintIndex & ~7;
|
|
}
|
|
|
|
/* First margin is end of bitmap */
|
|
Margin = BitMapHeader->SizeOfBitMap;
|
|
|
|
retry:
|
|
/* Start with hint index, length is 0 */
|
|
CurrentBit = HintIndex;
|
|
|
|
/* Loop until something is found or the end is reached */
|
|
while (CurrentBit + NumberToFind < Margin)
|
|
{
|
|
/* Search for the next clear run, by skipping a set run */
|
|
CurrentBit += RtlpGetLengthOfRunSet(BitMapHeader,
|
|
CurrentBit,
|
|
MAXINDEX);
|
|
|
|
/* Get length of the clear bit run */
|
|
CurrentLength = RtlpGetLengthOfRunClear(BitMapHeader,
|
|
CurrentBit,
|
|
NumberToFind);
|
|
|
|
/* Is this long enough? */
|
|
if (CurrentLength >= NumberToFind)
|
|
{
|
|
/* It is */
|
|
return CurrentBit;
|
|
}
|
|
|
|
CurrentBit += CurrentLength;
|
|
}
|
|
|
|
/* Did we start at a hint? */
|
|
if (HintIndex)
|
|
{
|
|
/* Retry at the start */
|
|
Margin = min(HintIndex + NumberToFind, BitMapHeader->SizeOfBitMap);
|
|
HintIndex = 0;
|
|
goto retry;
|
|
}
|
|
|
|
/* Nothing found */
|
|
return MAXINDEX;
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindSetBits(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ BITMAP_INDEX NumberToFind,
|
|
_In_ BITMAP_INDEX HintIndex)
|
|
{
|
|
BITMAP_INDEX CurrentBit, Margin, CurrentLength;
|
|
|
|
/* Check for valid parameters */
|
|
if (!BitMapHeader || NumberToFind > BitMapHeader->SizeOfBitMap)
|
|
{
|
|
return MAXINDEX;
|
|
}
|
|
|
|
/* Check if the hint is outside the bitmap */
|
|
if (HintIndex >= BitMapHeader->SizeOfBitMap) HintIndex = 0;
|
|
|
|
/* Check for trivial case */
|
|
if (NumberToFind == 0)
|
|
{
|
|
/* Return hint rounded down to byte margin */
|
|
return HintIndex & ~7;
|
|
}
|
|
|
|
/* First margin is end of bitmap */
|
|
Margin = BitMapHeader->SizeOfBitMap;
|
|
|
|
retry:
|
|
/* Start with hint index, length is 0 */
|
|
CurrentBit = HintIndex;
|
|
|
|
/* Loop until something is found or the end is reached */
|
|
while (CurrentBit + NumberToFind <= Margin)
|
|
{
|
|
/* Search for the next set run, by skipping a clear run */
|
|
CurrentBit += RtlpGetLengthOfRunClear(BitMapHeader,
|
|
CurrentBit,
|
|
MAXINDEX);
|
|
|
|
/* Get length of the set bit run */
|
|
CurrentLength = RtlpGetLengthOfRunSet(BitMapHeader,
|
|
CurrentBit,
|
|
NumberToFind);
|
|
|
|
/* Is this long enough? */
|
|
if (CurrentLength >= NumberToFind)
|
|
{
|
|
/* It is */
|
|
return CurrentBit;
|
|
}
|
|
|
|
CurrentBit += CurrentLength;
|
|
}
|
|
|
|
/* Did we start at a hint? */
|
|
if (HintIndex)
|
|
{
|
|
/* Retry at the start */
|
|
Margin = min(HintIndex + NumberToFind, BitMapHeader->SizeOfBitMap);
|
|
HintIndex = 0;
|
|
goto retry;
|
|
}
|
|
|
|
/* Nothing found */
|
|
return MAXINDEX;
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindClearBitsAndSet(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ BITMAP_INDEX NumberToFind,
|
|
_In_ BITMAP_INDEX HintIndex)
|
|
{
|
|
BITMAP_INDEX Position;
|
|
|
|
/* Try to find clear bits */
|
|
Position = RtlFindClearBits(BitMapHeader, NumberToFind, HintIndex);
|
|
|
|
/* Did we get something? */
|
|
if (Position != MAXINDEX)
|
|
{
|
|
/* Yes, set the bits */
|
|
RtlSetBits(BitMapHeader, Position, NumberToFind);
|
|
}
|
|
|
|
/* Return what we found */
|
|
return Position;
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindSetBitsAndClear(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ BITMAP_INDEX NumberToFind,
|
|
_In_ BITMAP_INDEX HintIndex)
|
|
{
|
|
BITMAP_INDEX Position;
|
|
|
|
/* Try to find set bits */
|
|
Position = RtlFindSetBits(BitMapHeader, NumberToFind, HintIndex);
|
|
|
|
/* Did we get something? */
|
|
if (Position != MAXINDEX)
|
|
{
|
|
/* Yes, clear the bits */
|
|
RtlClearBits(BitMapHeader, Position, NumberToFind);
|
|
}
|
|
|
|
/* Return what we found */
|
|
return Position;
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindNextForwardRunClear(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ BITMAP_INDEX FromIndex,
|
|
_Out_ PBITMAP_INDEX StartingRunIndex)
|
|
{
|
|
BITMAP_INDEX Length;
|
|
|
|
/* Check for buffer overrun */
|
|
if (FromIndex >= BitMapHeader->SizeOfBitMap)
|
|
{
|
|
*StartingRunIndex = FromIndex;
|
|
return 0;
|
|
}
|
|
|
|
/* Assume a set run first, count it's length */
|
|
Length = RtlpGetLengthOfRunSet(BitMapHeader, FromIndex, MAXINDEX);
|
|
*StartingRunIndex = FromIndex + Length;
|
|
|
|
/* Now return the length of the run */
|
|
return RtlpGetLengthOfRunClear(BitMapHeader, FromIndex + Length, MAXINDEX);
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindNextForwardRunSet(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ BITMAP_INDEX FromIndex,
|
|
_Out_ PBITMAP_INDEX StartingRunIndex)
|
|
{
|
|
BITMAP_INDEX Length;
|
|
|
|
/* Check for buffer overrun */
|
|
if (FromIndex >= BitMapHeader->SizeOfBitMap)
|
|
{
|
|
*StartingRunIndex = FromIndex;
|
|
return 0;
|
|
}
|
|
|
|
/* Assume a clear run first, count it's length */
|
|
Length = RtlpGetLengthOfRunClear(BitMapHeader, FromIndex, MAXINDEX);
|
|
*StartingRunIndex = FromIndex + Length;
|
|
|
|
/* Now return the length of the run */
|
|
return RtlpGetLengthOfRunSet(BitMapHeader, FromIndex + Length, MAXINDEX);
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindFirstRunClear(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_Out_ PBITMAP_INDEX StartingIndex)
|
|
{
|
|
return RtlFindNextForwardRunClear(BitMapHeader, 0, StartingIndex);
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindLastBackwardRunClear(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ BITMAP_INDEX FromIndex,
|
|
_Out_ PBITMAP_INDEX StartingRunIndex)
|
|
{
|
|
BITMAP_INDEX Value, InvValue, BitPos;
|
|
PBITMAP_BUFFER Buffer;
|
|
|
|
/* Make sure we don't go past the end */
|
|
FromIndex = min(FromIndex, BitMapHeader->SizeOfBitMap - 1);
|
|
|
|
/* Calculate positions */
|
|
Buffer = BitMapHeader->Buffer + FromIndex / _BITCOUNT;
|
|
BitPos = (_BITCOUNT - 1) - (FromIndex & (_BITCOUNT - 1));
|
|
|
|
/* Get the inversed value, clear bits that don't belong to the run */
|
|
InvValue = ~(*Buffer--) << BitPos >> BitPos;
|
|
|
|
/* Skip all set ULONGs */
|
|
while (InvValue == 0)
|
|
{
|
|
/* Did we already reach past the first ULONG? */
|
|
if (Buffer < BitMapHeader->Buffer)
|
|
{
|
|
/* Yes, nothing found */
|
|
return 0;
|
|
}
|
|
|
|
InvValue = ~(*Buffer--);
|
|
}
|
|
|
|
/* We hit a clear bit, check how many set bits are left */
|
|
BitScanReverse(&BitPos, InvValue);
|
|
|
|
/* Calculate last bit position */
|
|
FromIndex = (BITMAP_INDEX)((Buffer + 1 - BitMapHeader->Buffer) * _BITCOUNT + BitPos);
|
|
|
|
Value = ~InvValue << ((_BITCOUNT - 1) - BitPos) >> ((_BITCOUNT - 1) - BitPos);
|
|
|
|
/* Skip all clear ULONGs */
|
|
while (Value == 0 && Buffer >= BitMapHeader->Buffer)
|
|
{
|
|
Value = *Buffer--;
|
|
}
|
|
|
|
if (Value != 0)
|
|
{
|
|
/* We hit a set bit, check how many clear bits are left */
|
|
BitScanReverse(&BitPos, Value);
|
|
|
|
/* Calculate Starting Index */
|
|
*StartingRunIndex = (BITMAP_INDEX)((Buffer + 1 - BitMapHeader->Buffer) * _BITCOUNT + BitPos + 1);
|
|
}
|
|
else
|
|
{
|
|
/* We reached the start of the bitmap */
|
|
*StartingRunIndex = 0;
|
|
}
|
|
|
|
/* Return length of the run */
|
|
return (FromIndex - *StartingRunIndex);
|
|
}
|
|
|
|
|
|
ULONG
|
|
NTAPI
|
|
RtlFindClearRuns(
|
|
_In_ PRTL_BITMAP BitMapHeader,
|
|
_In_ PRTL_BITMAP_RUN RunArray,
|
|
_In_ ULONG SizeOfRunArray,
|
|
_In_ BOOLEAN LocateLongestRuns)
|
|
{
|
|
BITMAP_INDEX StartingIndex, NumberOfBits, FromIndex = 0, SmallestRun = 0;
|
|
ULONG Run;
|
|
|
|
/* Loop the runs */
|
|
for (Run = 0; Run < SizeOfRunArray; Run++)
|
|
{
|
|
/* Look for a run */
|
|
NumberOfBits = RtlFindNextForwardRunClear(BitMapHeader,
|
|
FromIndex,
|
|
&StartingIndex);
|
|
|
|
/* Nothing more found? Quit looping. */
|
|
if (NumberOfBits == 0) break;
|
|
|
|
/* Add another run */
|
|
RunArray[Run].StartingIndex = StartingIndex;
|
|
RunArray[Run].NumberOfBits = NumberOfBits;
|
|
|
|
/* Update smallest run */
|
|
if (NumberOfBits < RunArray[SmallestRun].NumberOfBits)
|
|
{
|
|
SmallestRun = Run;
|
|
}
|
|
|
|
/* Advance bits */
|
|
FromIndex = StartingIndex + NumberOfBits;
|
|
}
|
|
|
|
/* Check if we are finished */
|
|
if (Run < SizeOfRunArray || !LocateLongestRuns)
|
|
{
|
|
/* Return the number of found runs */
|
|
return Run;
|
|
}
|
|
|
|
while (1)
|
|
{
|
|
/* Look for a run */
|
|
NumberOfBits = RtlFindNextForwardRunClear(BitMapHeader,
|
|
FromIndex,
|
|
&StartingIndex);
|
|
|
|
/* Nothing more found? Quit looping. */
|
|
if (NumberOfBits == 0) break;
|
|
|
|
/* Check if we have something to update */
|
|
if (NumberOfBits > RunArray[SmallestRun].NumberOfBits)
|
|
{
|
|
/* Update smallest run */
|
|
RunArray[SmallestRun].StartingIndex = StartingIndex;
|
|
RunArray[SmallestRun].NumberOfBits = NumberOfBits;
|
|
|
|
/* Loop all runs */
|
|
for (Run = 0; Run < SizeOfRunArray; Run++)
|
|
{
|
|
/*Is this the new smallest run? */
|
|
if (NumberOfBits < RunArray[SmallestRun].NumberOfBits)
|
|
{
|
|
/* Set it as new smallest run */
|
|
SmallestRun = Run;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Advance bits */
|
|
FromIndex += NumberOfBits;
|
|
}
|
|
|
|
return Run;
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindLongestRunClear(
|
|
IN PRTL_BITMAP BitMapHeader,
|
|
IN PBITMAP_INDEX StartingIndex)
|
|
{
|
|
BITMAP_INDEX NumberOfBits, Index, MaxNumberOfBits = 0, FromIndex = 0;
|
|
|
|
while (1)
|
|
{
|
|
/* Look for a run */
|
|
NumberOfBits = RtlFindNextForwardRunClear(BitMapHeader,
|
|
FromIndex,
|
|
&Index);
|
|
|
|
/* Nothing more found? Quit looping. */
|
|
if (NumberOfBits == 0) break;
|
|
|
|
/* Was that the longest run? */
|
|
if (NumberOfBits > MaxNumberOfBits)
|
|
{
|
|
/* Update values */
|
|
MaxNumberOfBits = NumberOfBits;
|
|
*StartingIndex = Index;
|
|
}
|
|
|
|
/* Advance bits */
|
|
FromIndex += NumberOfBits;
|
|
}
|
|
|
|
return MaxNumberOfBits;
|
|
}
|
|
|
|
BITMAP_INDEX
|
|
NTAPI
|
|
RtlFindLongestRunSet(
|
|
IN PRTL_BITMAP BitMapHeader,
|
|
IN PBITMAP_INDEX StartingIndex)
|
|
{
|
|
BITMAP_INDEX NumberOfBits, Index, MaxNumberOfBits = 0, FromIndex = 0;
|
|
|
|
while (1)
|
|
{
|
|
/* Look for a run */
|
|
NumberOfBits = RtlFindNextForwardRunSet(BitMapHeader,
|
|
FromIndex,
|
|
&Index);
|
|
|
|
/* Nothing more found? Quit looping. */
|
|
if (NumberOfBits == 0) break;
|
|
|
|
/* Was that the longest run? */
|
|
if (NumberOfBits > MaxNumberOfBits)
|
|
{
|
|
/* Update values */
|
|
MaxNumberOfBits = NumberOfBits;
|
|
*StartingIndex = Index;
|
|
}
|
|
|
|
/* Advance bits */
|
|
FromIndex += NumberOfBits;
|
|
}
|
|
|
|
return MaxNumberOfBits;
|
|
}
|
|
|