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NeXTSTEP 3.3 (Developer)…68k, x86, SPARC, PA-RISC]
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NeXTSTEP 3.3 Dev Intel.iso
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btree
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IXPostingCursor.h
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1993-08-15
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/*
IXPostingCursor.h
Copyright 1991,NeXT Computer,Inc.
*/
#import "IXBTreeCursor.h"
// This class implements an inversion cursor. It manages the values, as well
// as the keys, stored in the BTree. The values are lists of weighted handles.
// A handle is an arbitrary identifier. The weight is an arbitrary unsigned
// integer value that could represent term weighting for text retrieval, or a
// hint for fast secondary key access.
// The handles for a given key are represented internally as sixteen bit
// quantities until the first handle is seen that requires more than sixteen
// bits; at that point, all of the handles for the key are represented
// internally as thirty two bit quantities. The weights for a given key are
// omitted until a non zero weight is seen; at that point, all of the handles
// are weighted using sixteen or thirty two bits, accordingly. When the length
// of the list surpasses four blocks, it is represented internally as a BTree.
#ifdef NX_COMPILER_RELEASE_3_0
@interface IXPostingCursor: IXBTreeCursor <IXPostingExchange, IXPostingOperations>
#else NX_COMPILER_RELEASE_3_0
@interface IXPostingCursor: IXBTreeCursor
#endif NX_COMPILER_RELEASE_3_0
{
IXPosting *_thisPosting;
struct PostingArray *_cursorValue;
unsigned _cursorLength;
IXBTreeCursor *_valueCursor;
}
@end