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Introduce distance operators over cubes: <#> taxicab distance <-> euclidean distance <=> chebyshev distance Also add kNN support of those distances in GiST opclass. Author: Stas Kelvich
63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/* contrib/cube/cubedata.h */
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#define CUBE_MAX_DIM (100)
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typedef struct NDBOX
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{
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/* varlena header (do not touch directly!) */
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int32 vl_len_;
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/*----------
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* Header contains info about NDBOX. For binary compatibility with old
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* versions, it is defined as "unsigned int".
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*
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* Following information is stored:
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*
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* bits 0-7 : number of cube dimensions;
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* bits 8-30 : unused, initialize to zero;
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* bit 31 : point flag. If set, the upper right coordinates are not
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* stored, and are implicitly the same as the lower left
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* coordinates.
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*----------
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*/
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unsigned int header;
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/*
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* The lower left coordinates for each dimension come first, followed by
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* upper right coordinates unless the point flag is set.
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*/
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double x[FLEXIBLE_ARRAY_MEMBER];
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} NDBOX;
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#define POINT_BIT 0x80000000
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#define DIM_MASK 0x7fffffff
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#define IS_POINT(cube) ( ((cube)->header & POINT_BIT) != 0 )
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#define SET_POINT_BIT(cube) ( (cube)->header |= POINT_BIT )
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#define DIM(cube) ( (cube)->header & DIM_MASK )
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#define SET_DIM(cube, _dim) ( (cube)->header = ((cube)->header & ~DIM_MASK) | (_dim) )
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#define LL_COORD(cube, i) ( (cube)->x[i] )
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#define UR_COORD(cube, i) ( IS_POINT(cube) ? (cube)->x[i] : (cube)->x[(i) + DIM(cube)] )
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#define POINT_SIZE(_dim) (offsetof(NDBOX, x) + sizeof(double)*(_dim))
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#define CUBE_SIZE(_dim) (offsetof(NDBOX, x) + sizeof(double)*(_dim)*2)
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#define DatumGetNDBOX(x) ((NDBOX *) PG_DETOAST_DATUM(x))
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#define PG_GETARG_NDBOX(x) DatumGetNDBOX(PG_GETARG_DATUM(x))
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#define PG_RETURN_NDBOX(x) PG_RETURN_POINTER(x)
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#define CubeKNNDistanceCoord 15 /* ~> */
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#define CubeKNNDistanceTaxicab 16 /* <#> */
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#define CubeKNNDistanceEuclid 17 /* <-> */
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#define CubeKNNDistanceChebyshev 18 /* <=> */
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/* in cubescan.l */
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extern int cube_yylex(void);
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extern void cube_yyerror(NDBOX **result, const char *message) pg_attribute_noreturn();
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extern void cube_scanner_init(const char *str);
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extern void cube_scanner_finish(void);
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/* in cubeparse.y */
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extern int cube_yyparse(NDBOX **result);
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