120 lines
3.2 KiB
C
120 lines
3.2 KiB
C
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/*
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redblack.h
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Prototypes and node structure definition for red-black binary trees.
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See redblack.c for details and implementation.
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Author: Tom McGuire (tommcg) 1/98
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Copyright (C) Microsoft, 1998.
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2/98, modified this version of redblack.h for debug symbol lookups.
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*/
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#ifndef _REDBLACK_H_
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#define _REDBLACK_H_
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typedef struct _SYMBOL_NODE SYMBOL_NODE, *PSYMBOL_NODE;
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typedef struct _SYMBOL_TREE SYMBOL_TREE, *PSYMBOL_TREE;
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struct _SYMBOL_NODE {
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PSYMBOL_NODE Left;
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PSYMBOL_NODE Right;
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ULONG Hash;
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union {
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ULONG RvaWithStatusBits;
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struct {
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ULONG Rva:30;
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ULONG Hit:1;
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ULONG Red:1;
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};
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};
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CHAR SymbolName[ 0 ];
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};
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struct _SYMBOL_TREE {
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PSYMBOL_NODE Root;
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HANDLE SubAllocator;
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#if defined( DEBUG ) || defined( DBG ) || defined( TESTCODE )
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ULONG CountNodes;
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BOOL DeletedAny;
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#endif
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};
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#define RBNIL ((PSYMBOL_NODE)&SymRBEmptyNode)
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extern const SYMBOL_NODE SymRBEmptyNode;
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//
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// Although "Red" can be stored in its own 1-byte or 4-byte field, keeping the
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// nodes smaller by encoding "Red" as a one-bit field with another value
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// provides better performance (more nodes tend to stay in the cache). To
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// provide flexibility in storage of the RED property, all references to RED
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// and BLACK are made through the following macros which can be changed as
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// necessary:
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//
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#define IS_RED( Node ) ( (Node)->Red )
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#define IS_BLACK( Node ) ( ! (Node)->Red )
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#define MARK_RED( Node ) ( (Node)->Red = 1 )
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#define MARK_BLACK( Node ) ( (Node)->Red = 0 )
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//
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// The maximum tree depth is 2*Lg(N). Since we could never have more than
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// 2^X nodes with X-bit pointers, we can safely say the absolute maximum
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// depth will be 2*Lg(2^X) which is 2*X. The size of a pointer in bits is
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// its size in bytes times 8 bits, so 2*(sizeof(p)*8) is our maximum depth.
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// So for 32-bit pointers, our maximum depth is 64.
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//
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// If you know the maximum possible number of nodes in advance (like the size
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// of the address space divided by the size of a node), you can tweak this
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// value a bit smaller to 2*Lg(N). Note that it's important for this max
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// depth be evalutated to a constant value at compile time.
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//
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// For this implementation, we'll assume the maximum number of nodes is
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// 128 million, so the max depth is 54 (2*Lg(2^27)). Note that no runtime
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// checks are made to ensure we don't exceed this number, but since our
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// minimum node allocation size is 32 bytes, that would be a maximum of
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// 100 million nodes in a 3GB address space.
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//
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#define MAX_DEPTH 54
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//
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// The following prototypes are the red-black tree interface.
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//
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VOID
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SymRBInitTree(
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IN OUT PSYMBOL_TREE Tree,
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IN HANDLE SubAllocator
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);
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PSYMBOL_NODE
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SymRBInsert(
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IN OUT PSYMBOL_TREE Tree,
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IN LPSTR SymbolName,
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IN ULONG Rva
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);
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PSYMBOL_NODE
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SymRBFind(
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IN PSYMBOL_TREE Tree,
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IN LPSTR SymbolName
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);
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PSYMBOL_NODE
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SymRBFindAndDelete(
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IN OUT PSYMBOL_TREE Tree,
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IN LPSTR SymbolName
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);
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#endif // _REDBLACK_H_
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