4 * Definitions for the exact numeric data type of Postgres
8 * $Header: /cvsroot/pgsql/src/include/utils/numeric.h,v 1.15 2001/11/05 17:46:36 momjian Exp $
13 #ifndef _PG_NUMERIC_H_
14 #define _PG_NUMERIC_H_
17 * The hardcoded limits and defaults of the numeric data type
20 #define NUMERIC_MAX_PRECISION 1000
21 #define NUMERIC_DEFAULT_PRECISION 30
22 #define NUMERIC_DEFAULT_SCALE 6
26 * Internal limits on the scales chosen for calculation results
29 #define NUMERIC_MAX_DISPLAY_SCALE NUMERIC_MAX_PRECISION
30 #define NUMERIC_MIN_DISPLAY_SCALE (NUMERIC_DEFAULT_SCALE + 4)
32 #define NUMERIC_MAX_RESULT_SCALE (NUMERIC_MAX_PRECISION * 2)
33 #define NUMERIC_MIN_RESULT_SCALE (NUMERIC_DEFAULT_PRECISION + 4)
37 * Sign values and macros to deal with packing/unpacking n_sign_dscale
40 #define NUMERIC_SIGN_MASK 0xC000
41 #define NUMERIC_POS 0x0000
42 #define NUMERIC_NEG 0x4000
43 #define NUMERIC_NAN 0xC000
44 #define NUMERIC_DSCALE_MASK 0x3FFF
45 #define NUMERIC_SIGN(n) ((n)->n_sign_dscale & NUMERIC_SIGN_MASK)
46 #define NUMERIC_DSCALE(n) ((n)->n_sign_dscale & NUMERIC_DSCALE_MASK)
47 #define NUMERIC_IS_NAN(n) (NUMERIC_SIGN(n) != NUMERIC_POS && \
48 NUMERIC_SIGN(n) != NUMERIC_NEG)
52 * The Numeric data type stored in the database
54 * NOTE: by convention, values in the packed form have been stripped of
55 * all leading and trailing zeroes (except there will be a trailing zero
56 * in the last byte, if the number of digits is odd). In particular,
57 * if the value is zero, there will be no digits at all! The weight is
58 * arbitrary in that case, but we normally set it to zero.
61 typedef struct NumericData
63 int32 varlen; /* Variable size */
64 int16 n_weight; /* Weight of 1st digit */
65 uint16 n_rscale; /* Result scale */
66 uint16 n_sign_dscale; /* Sign + display scale */
67 unsigned char n_data[1]; /* Digit data (2 decimal digits/byte) */
69 typedef NumericData *Numeric;
71 #define NUMERIC_HDRSZ (sizeof(int32) + sizeof(uint16) * 3)
75 * fmgr interface macros
78 #define DatumGetNumeric(X) ((Numeric) PG_DETOAST_DATUM(X))
79 #define DatumGetNumericCopy(X) ((Numeric) PG_DETOAST_DATUM_COPY(X))
80 #define NumericGetDatum(X) PointerGetDatum(X)
81 #define PG_GETARG_NUMERIC(n) DatumGetNumeric(PG_GETARG_DATUM(n))
82 #define PG_GETARG_NUMERIC_COPY(n) DatumGetNumericCopy(PG_GETARG_DATUM(n))
83 #define PG_RETURN_NUMERIC(x) return NumericGetDatum(x)
85 #endif /* _PG_NUMERIC_H_ */