179 lines
4.1 KiB
C
179 lines
4.1 KiB
C
/*++
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Copyright (c) 1991 Microsoft Corporation
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Module Name:
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blrange.h
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Abstract:
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This module declares ranges, rangelists and their methods. These
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can be used to keep track of cached ranges of a disk for instance.
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Author:
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Cenk Ergan (cenke) 11-Jan-2000
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Revision History:
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--*/
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#ifndef _BLRANGE_H
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#define _BLRANGE_H
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#include "bldr.h"
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//
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// Define range & range list data structures.
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//
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//
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// NOTE: BLCRANGE's Start is inclusive and End is exclusive. E.g.
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// 200-400 contains 200th but does not contain 400th byte, apple,
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// meter etc. This allows a single subtraction to determine the
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// number of elements in the range.
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//
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//
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// NOTE: BLCRANGE's Start should be less than or equal to its End.
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//
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//
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// Representing ranges with start and end instead of start and length
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// seems to simplify the code and remove a lot of addition and
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// subtractions. We could maybe use a ULONG Length, which would save 4
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// bytes per range, but lists make it hard to have thousands of ranges
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// and even if you had 10 thousand ranges, you'd save only 40KB, which
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// seemed to be insignificant to the cons above when I began changing
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// the code to have Length instead of End. With both Start and End
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// ULONGLONG more data can be represented by ranges, e.g. 64bit
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// offsets [memory or disk] where 4GB Length may not be enough.
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//
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typedef struct _BLCRANGE
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{
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ULONGLONG Start;
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ULONGLONG End;
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} BLCRANGE, *PBLCRANGE;
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typedef struct _BLCRANGE_ENTRY
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{
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LIST_ENTRY Link;
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BLCRANGE Range;
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PVOID UserData; // UserData field is not used by range functions.
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LIST_ENTRY UserLink; // UserLink field is not used by range functions.
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} BLCRANGE_ENTRY, *PBLCRANGE_ENTRY;
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//
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// Define range entry merging routine type. This routine should
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// perform the necessary operations to merge the user controlled /
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// maintained Data field of the pSrcEntry to pDestEntry's Data
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// field. It should not manipulate any other BLCRANGE_ENTRT fields. It
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// should return FALSE if there was an error and it could not merge
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// the two Data fields, TRUE otherwise. If it returns FALSE, it should
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// undo its modifications to pDestEntry and pSrcEntry.
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//
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typedef
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BOOLEAN
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(*PBLCRANGE_MERGE_ROUTINE) (
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PBLCRANGE_ENTRY pDestEntry,
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PBLCRANGE_ENTRY pSrcEntry
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);
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//
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// Define range entry free'ing routine type. This routine should free
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// all the resources & memory allocated for a range entry.
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//
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typedef
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VOID
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(*PBLCRANGE_FREE_ROUTINE) (
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PBLCRANGE_ENTRY pRangeEntry
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);
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//
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// BLCRANGE_LIST maintains a sorted list of non-overlapping range
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// entries off its Head field.
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//
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typedef struct _BLCRANGE_LIST
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{
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LIST_ENTRY Head;
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ULONG NumEntries;
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PBLCRANGE_MERGE_ROUTINE MergeRoutine;
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PBLCRANGE_FREE_ROUTINE FreeRoutine;
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} BLCRANGE_LIST, *PBLCRANGE_LIST;
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//
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// Useful macros. Be mindful of expression reevaluation as with
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// all macros.
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//
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#define BLRGMIN(a,b) (((a) <= (b)) ? (a) : (b))
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#define BLRGMAX(a,b) (((a) >= (b)) ? (a) : (b))
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//
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// Range function prototypes. See ntos\boot\lib\blrange.c for comments
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// and implementation.
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//
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VOID
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BlRangeListInitialize (
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PBLCRANGE_LIST pRangeList,
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OPTIONAL PBLCRANGE_MERGE_ROUTINE pMergeRoutine,
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OPTIONAL PBLCRANGE_FREE_ROUTINE pFreeRoutine
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);
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BOOLEAN
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BlRangeListAddRange (
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PBLCRANGE_LIST pRangeList,
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PBLCRANGE_ENTRY pRangeEntry
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);
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BOOLEAN
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BlRangeListFindOverlaps (
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PBLCRANGE_LIST pRangeList,
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PBLCRANGE pRange,
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PBLCRANGE_ENTRY *pOverlapsBuffer,
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ULONG OverlapsBufferSize,
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OUT ULONG *pNumOverlaps
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);
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BOOLEAN
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BlRangeListFindDistinctRanges (
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PBLCRANGE_LIST pRangeList,
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PBLCRANGE pRange,
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PBLCRANGE pDistinctRanges,
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ULONG BufferSize,
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OUT ULONG *pNumRanges
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);
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VOID
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BlRangeListRemoveRange (
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PBLCRANGE_LIST pRangeList,
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PBLCRANGE pRange
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);
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VOID
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BlRangeListRemoveAllRanges (
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PBLCRANGE_LIST pRangeList
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);
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BOOLEAN
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BlRangeListMergeRangeEntries (
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PBLCRANGE_LIST pRangeList,
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PBLCRANGE_ENTRY pDestEntry,
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PBLCRANGE_ENTRY pSrcEntry
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);
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BOOLEAN
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BlRangeEntryMerge (
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PBLCRANGE_ENTRY pDestEntry,
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PBLCRANGE_ENTRY pSrcEntry,
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OPTIONAL PBLCRANGE_MERGE_ROUTINE pMergeRoutine
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);
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#endif // _BLRANGE_H
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