src/include/utils/numeric.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * numeric.h
   4  *        Definitions for the exact numeric data type of Postgres
   5  *
   6  * Original coding 1998, Jan Wieck.  Heavily revised 2003, Tom Lane.
   7  *
   8  * Copyright (c) 1998-2022, PostgreSQL Global Development Group
   9  *
  10  * src/include/utils/numeric.h
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #ifndef _PG_NUMERIC_H_
  15 #define _PG_NUMERIC_H_
  16
  17 #include "fmgr.h"
  18
  19 /*
  20  * Limits on the precision and scale specifiable in a NUMERIC typmod.  The
  21  * precision is strictly positive, but the scale may be positive or negative.
  22  * A negative scale implies rounding before the decimal point.
  23  *
  24  * Note that the minimum display scale defined below is zero --- we always
  25  * display all digits before the decimal point, even when the scale is
  26  * negative.
  27  *
  28  * Note that the implementation limits on the precision and display scale of a
  29  * numeric value are much larger --- beware of what you use these for!
  30  */
  31 #define NUMERIC_MAX_PRECISION           1000
  32
  33 #define NUMERIC_MIN_SCALE                       (-1000)
  34 #define NUMERIC_MAX_SCALE                       1000
  35
  36 /*
  37  * Internal limits on the scales chosen for calculation results
  38  */
  39 #define NUMERIC_MAX_DISPLAY_SCALE       NUMERIC_MAX_PRECISION
  40 #define NUMERIC_MIN_DISPLAY_SCALE       0
  41
  42 #define NUMERIC_MAX_RESULT_SCALE        (NUMERIC_MAX_PRECISION * 2)
  43
  44 /*
  45  * For inherently inexact calculations such as division and square root,
  46  * we try to get at least this many significant digits; the idea is to
  47  * deliver a result no worse than float8 would.
  48  */
  49 #define NUMERIC_MIN_SIG_DIGITS          16
  50
  51 /* The actual contents of Numeric are private to numeric.c */
  52 struct NumericData;
  53 typedef struct NumericData *Numeric;
  54
  55 /*
  56  * fmgr interface macros
  57  */
  58
  59 #define DatumGetNumeric(X)                ((Numeric) PG_DETOAST_DATUM(X))
  60 #define DatumGetNumericCopy(X)    ((Numeric) PG_DETOAST_DATUM_COPY(X))
  61 #define NumericGetDatum(X)                PointerGetDatum(X)
  62 #define PG_GETARG_NUMERIC(n)      DatumGetNumeric(PG_GETARG_DATUM(n))
  63 #define PG_GETARG_NUMERIC_COPY(n) DatumGetNumericCopy(PG_GETARG_DATUM(n))
  64 #define PG_RETURN_NUMERIC(x)      return NumericGetDatum(x)
  65
  66 /*
  67  * Utility functions in numeric.c
  68  */
  69 extern bool numeric_is_nan(Numeric num);
  70 extern bool numeric_is_inf(Numeric num);
  71 int32           numeric_maximum_size(int32 typmod);
  72 extern char *numeric_out_sci(Numeric num, int scale);
  73 extern char *numeric_normalize(Numeric num);
  74
  75 extern Numeric int64_to_numeric(int64 val);
  76 extern Numeric int64_div_fast_to_numeric(int64 val1, int log10val2);
  77
  78 extern Numeric numeric_add_opt_error(Numeric num1, Numeric num2,
  79                                                                          bool *have_error);
  80 extern Numeric numeric_sub_opt_error(Numeric num1, Numeric num2,
  81                                                                          bool *have_error);
  82 extern Numeric numeric_mul_opt_error(Numeric num1, Numeric num2,
  83                                                                          bool *have_error);
  84 extern Numeric numeric_div_opt_error(Numeric num1, Numeric num2,
  85                                                                          bool *have_error);
  86 extern Numeric numeric_mod_opt_error(Numeric num1, Numeric num2,
  87                                                                          bool *have_error);
  88 extern int32 numeric_int4_opt_error(Numeric num, bool *error);
  89
  90 #endif                                                  /* _PG_NUMERIC_H_ */