postgresql/contrib/cube/cubedata.h
Teodor Sigaev 33bd250f6c Cube extension kNN support
Introduce distance operators over cubes:
<#> taxicab distance
<->  euclidean distance
<=> chebyshev distance

Also add kNN support of those distances in GiST opclass.

Author: Stas Kelvich
2015-12-18 14:38:27 +03:00

63 lines
2.0 KiB
C

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