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/*-------------------------------------------------------------------------
*
* numeric.h
* Definitions for the exact numeric data type of Postgres
*
* Original coding 1998, Jan Wieck. Heavily revised 2003, Tom Lane.
*
* Copyright (c) 1998-2004, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/include/utils/numeric.h,v 1.19 2004/08/29 04:13:11 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef _PG_NUMERIC_H_
#define _PG_NUMERIC_H_
/*
* Hardcoded precision limit - arbitrary, but must be small enough that
* dscale values will fit in 14 bits.
*/
#define NUMERIC_MAX_PRECISION 1000
/*
* Internal limits on the scales chosen for calculation results
*/
#define NUMERIC_MAX_DISPLAY_SCALE NUMERIC_MAX_PRECISION
#define NUMERIC_MIN_DISPLAY_SCALE 0
#define NUMERIC_MAX_RESULT_SCALE (NUMERIC_MAX_PRECISION * 2)
/*
* For inherently inexact calculations such as division and square root,
* we try to get at least this many significant digits; the idea is to
* deliver a result no worse than float8 would.
*/
#define NUMERIC_MIN_SIG_DIGITS 16
/*
* Sign values and macros to deal with packing/unpacking n_sign_dscale
*/
#define NUMERIC_SIGN_MASK 0xC000
#define NUMERIC_POS 0x0000
#define NUMERIC_NEG 0x4000
#define NUMERIC_NAN 0xC000
#define NUMERIC_DSCALE_MASK 0x3FFF
#define NUMERIC_SIGN(n) ((n)->n_sign_dscale & NUMERIC_SIGN_MASK)
#define NUMERIC_DSCALE(n) ((n)->n_sign_dscale & NUMERIC_DSCALE_MASK)
#define NUMERIC_IS_NAN(n) (NUMERIC_SIGN(n) != NUMERIC_POS && \
NUMERIC_SIGN(n) != NUMERIC_NEG)
/*
* The Numeric data type stored in the database
*
* NOTE: by convention, values in the packed form have been stripped of
* all leading and trailing zero digits (where a "digit" is of base NBASE).
* In particular, if the value is zero, there will be no digits at all!
* The weight is arbitrary in that case, but we normally set it to zero.
*/
typedef struct NumericData
{
int32 varlen; /* Variable size (std varlena header) */
int16 n_weight; /* Weight of 1st digit */
uint16 n_sign_dscale; /* Sign + display scale */
char n_data[1]; /* Digits (really array of NumericDigit) */
} NumericData;
typedef NumericData *Numeric;
#define NUMERIC_HDRSZ (sizeof(int32) + sizeof(int16) + sizeof(uint16))
/*
* fmgr interface macros
*/
#define DatumGetNumeric(X) ((Numeric) PG_DETOAST_DATUM(X))
#define DatumGetNumericCopy(X) ((Numeric) PG_DETOAST_DATUM_COPY(X))
#define NumericGetDatum(X) PointerGetDatum(X)
#define PG_GETARG_NUMERIC(n) DatumGetNumeric(PG_GETARG_DATUM(n))
#define PG_GETARG_NUMERIC_COPY(n) DatumGetNumericCopy(PG_GETARG_DATUM(n))
#define PG_RETURN_NUMERIC(x) return NumericGetDatum(x)
#endif /* _PG_NUMERIC_H_ */
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