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// -*- Mode: C++ -*- |
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|
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// GiSTpath.h |
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// |
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// Copyright (c) 1996, Regents of the University of California |
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// $Header: /usr/local/devel/GiST/libGiST/libGiST/GiSTpath.h,v 1.1.1.1 1996/08/06 23:47:21 jmh Exp $ |
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#ifndef GISTPATH_H |
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#define GISTPATH_H |
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|
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// GiSTpath objects store the path to a node from the root of the tree. |
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// The page number of each node visited is stored. For simplicity, |
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// GiSTpaths are stored as an array with max GIST_MAX_LEVELS elements. |
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// This can be expanded if you want a tree with more than 16 levels |
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// (not likely unless you have big keys, or small pages!) |
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|
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#define GiSTRootPage 1 |
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|
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#define GIST_MAX_LEVELS 16 |
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|
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class GiSTpath : public GiSTobject { |
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GiSTpage pages[GIST_MAX_LEVELS]; |
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int len; |
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public: |
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GiSTpath() { len=0; } |
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GiSTpath(const GiSTpath& path) { |
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len=path.len; |
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for(int i=0; i<path.len; i++) pages[i]=path.pages[i]; |
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} |
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|
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#ifdef PRINTING_OBJECTS |
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void Print(ostream& os) const { |
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os << '['; |
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for(int i=0; i<len; i++) { |
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if(i) os << ' '; |
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os << pages[i]; |
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} |
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os << ']'; |
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} |
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#endif |
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|
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int Level() const { |
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return len-1; |
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} |
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void Clear() { len=0; } |
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void MakeParent() { len--; } |
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void MakeSibling(GiSTpage page) { pages[len-1]=page; } |
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void MakeChild(GiSTpage page) { pages[len++]=page; } |
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void MakeRoot() { |
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len=1; |
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pages[0]=GiSTRootPage; |
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} |
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|
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void SplitRoot(GiSTpage page) { |
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for(int i=len; i>1; i--) pages[i]=pages[i-1]; |
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pages[1]=page; |
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pages[0]=GiSTRootPage; |
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} |
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|
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GiSTpath& operator = (const GiSTpath& path) { |
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len=path.len; |
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for(int i=0; i<path.len; i++) pages[i]=path.pages[i]; |
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return *this; |
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} |
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|
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int operator==(const GiSTpath& p) const { |
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if(len!=p.len) return(0); |
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for(int i=0; i<p.len; i++) if (pages[i]!=p.pages[i]) return(0); |
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return(1); |
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} |
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|
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GiSTpage Page() const { return pages[len-1]; } |
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GiSTpage Parent() const { return len>=2? pages[len-2]: 0; } |
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int IsRoot() const { return len==1; } |
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}; |
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|
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#endif |
