diff options
Diffstat (limited to 'src/backend/utils/adt/numeric.c')
| -rw-r--r-- | src/backend/utils/adt/numeric.c | 65 |
1 files changed, 64 insertions, 1 deletions
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 4b8271e45f5..327d5f0ddf7 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -14,7 +14,7 @@ * Copyright (c) 1998-2010, PostgreSQL Global Development Group * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.123 2010/02/26 02:01:09 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.124 2010/07/30 04:30:23 rhaas Exp $ * *------------------------------------------------------------------------- */ @@ -35,6 +35,38 @@ #include "utils/int8.h" #include "utils/numeric.h" +/* + * 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) +#define NUMERIC_HDRSZ (VARHDRSZ + sizeof(uint16) + sizeof(int16)) + + +/* + * 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. + */ +struct NumericData +{ + int32 vl_len_; /* varlena header (do not touch directly!) */ + uint16 n_sign_dscale; /* Sign + display scale */ + int16 n_weight; /* Weight of 1st digit */ + char n_data[1]; /* Digits (really array of NumericDigit) */ +}; + + /* ---------- * Uncomment the following to enable compilation of dump_numeric() * and dump_var() and to get a dump of any result produced by make_result(). @@ -428,6 +460,37 @@ numeric_out(PG_FUNCTION_ARGS) } /* + * numeric_is_nan() - + * + * Is Numeric value a NaN? + */ +bool +numeric_is_nan(Numeric num) +{ + return NUMERIC_IS_NAN(num); +} + +/* + * numeric_maximum_size() - + * + * Maximum size of a numeric with given typmod, or -1 if unlimited/unknown. + */ +int32 +numeric_maximum_size(int32 typemod) +{ + int precision; + + if (typemod <= VARHDRSZ) + return -1; + + /* precision (ie, max # of digits) is in upper bits of typmod */ + precision = ((typemod - VARHDRSZ) >> 16) & 0xffff; + + /* Numeric stores 2 decimal digits/byte, plus header */ + return (precision + 1) / 2 + NUMERIC_HDRSZ; +} + +/* * numeric_out_sci() - * * Output function for numeric data type in scientific notation. |