diff options
Diffstat (limited to 'src/include/utils/numeric.h')
| -rw-r--r-- | src/include/utils/numeric.h | 36 |
1 files changed, 21 insertions, 15 deletions
diff --git a/src/include/utils/numeric.h b/src/include/utils/numeric.h index f6050dfc659..a8148d59cea 100644 --- a/src/include/utils/numeric.h +++ b/src/include/utils/numeric.h @@ -5,7 +5,7 @@ * * 1998 Jan Wieck * - * $Header: /cvsroot/pgsql/src/include/utils/numeric.h,v 1.15 2001/11/05 17:46:36 momjian Exp $ + * $Id: numeric.h,v 1.16 2002/10/02 19:21:26 tgl Exp $ * * ---------- */ @@ -13,29 +13,36 @@ #ifndef _PG_NUMERIC_H_ #define _PG_NUMERIC_H_ -/* ---------- - * The hardcoded limits and defaults of the numeric data type - * ---------- +/* + * Hardcoded precision limit - arbitrary, but must be small enough that + * dscale values will fit in 14 bits. */ #define NUMERIC_MAX_PRECISION 1000 -#define NUMERIC_DEFAULT_PRECISION 30 -#define NUMERIC_DEFAULT_SCALE 6 - -/* ---------- +/* * Internal limits on the scales chosen for calculation results - * ---------- */ #define NUMERIC_MAX_DISPLAY_SCALE NUMERIC_MAX_PRECISION -#define NUMERIC_MIN_DISPLAY_SCALE (NUMERIC_DEFAULT_SCALE + 4) +#define NUMERIC_MIN_DISPLAY_SCALE 0 #define NUMERIC_MAX_RESULT_SCALE (NUMERIC_MAX_PRECISION * 2) -#define NUMERIC_MIN_RESULT_SCALE (NUMERIC_DEFAULT_PRECISION + 4) +/* + * 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 -/* ---------- +/* + * Standard number of extra digits carried internally while doing + * inexact calculations. + */ +#define NUMERIC_EXTRA_DIGITS 4 + + +/* * Sign values and macros to deal with packing/unpacking n_sign_dscale - * ---------- */ #define NUMERIC_SIGN_MASK 0xC000 #define NUMERIC_POS 0x0000 @@ -48,7 +55,7 @@ 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 @@ -56,7 +63,6 @@ * in the last byte, if the number of digits is odd). 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 { |