mariadb/include/decimal.h

/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */

#ifndef _decimal_h
#define _decimal_h

#ifdef __cplusplus
extern "C" {
#endif

typedef enum
{TRUNCATE=0, HALF_EVEN, HALF_UP, CEILING, FLOOR}
  decimal_round_mode;
typedef int32 decimal_digit_t;

/**
    intg is the number of *decimal* digits (NOT number of decimal_digit_t's !)
         before the point
    frac is the number of decimal digits after the point
    len  is the length of buf (length of allocated space) in decimal_digit_t's,
         not in bytes
    sign false means positive, true means negative
    buf  is an array of decimal_digit_t's
 */
typedef struct st_decimal_t {
  int    intg, frac, len;
  my_bool sign;
  decimal_digit_t *buf;
} decimal_t;

int internal_str2dec(const char *from, decimal_t *to, char **end,
                     my_bool fixed);
int decimal2string(const decimal_t *from, char *to, int *to_len,
                   decimal_digits_t fixed_precision,
                   decimal_digits_t fixed_decimals,
                   char filler);
int decimal2ulonglong(const decimal_t *from, ulonglong *to);
int ulonglong2decimal(ulonglong from, decimal_t *to);
int decimal2longlong(const decimal_t *from, longlong *to);
int longlong2decimal(longlong from, decimal_t *to);
int decimal2double(const decimal_t *from, double *to);
int double2decimal(double from, decimal_t *to);
decimal_digits_t decimal_actual_fraction(const decimal_t *from);
int decimal2bin(const decimal_t *from, uchar *to, decimal_digits_t precision,
                decimal_digits_t scale);
int bin2decimal(const uchar *from, decimal_t *to, decimal_digits_t precision,
                decimal_digits_t scale);

uint decimal_size(decimal_digits_t precision, decimal_digits_t scale);
uint decimal_bin_size(decimal_digits_t precision, decimal_digits_t scale);
uint decimal_result_size(decimal_t *from1, decimal_t *from2, char op,
                         int param);

decimal_digits_t decimal_intg(const decimal_t *from);
int decimal_add(const decimal_t *from1, const decimal_t *from2, decimal_t *to);
int decimal_sub(const decimal_t *from1, const decimal_t *from2, decimal_t *to);
int decimal_cmp(const decimal_t *from1, const decimal_t *from2);
int decimal_mul(const decimal_t *from1, const decimal_t *from2, decimal_t *to);
int decimal_div(const decimal_t *from1, const decimal_t *from2, decimal_t *to,
                int scale_incr);
int decimal_mod(const decimal_t *from1, const decimal_t *from2, decimal_t *to);
int decimal_round(const decimal_t *from, decimal_t *to, int new_scale,
                  decimal_round_mode mode);
int decimal_is_zero(const decimal_t *from);
void max_decimal(decimal_digits_t precision, decimal_digits_t frac,
                 decimal_t *to);

#define string2decimal(A,B,C) internal_str2dec((A), (B), (C), 0)
#define string2decimal_fixed(A,B,C) internal_str2dec((A), (B), (C), 1)

/* set a decimal_t to zero */

#define decimal_make_zero(dec)        do {                \
                                        (dec)->buf[0]=0;    \
                                        (dec)->intg=1;      \
                                        (dec)->frac=0;      \
                                        (dec)->sign=0;      \
                                      } while(0)

/*
  returns the length of the buffer to hold string representation
  of the decimal (including decimal dot, possible sign and \0)
*/

#define decimal_string_size(dec) (((dec)->intg ? (dec)->intg : 1) + \
				  (dec)->frac + ((dec)->frac > 0) + 2)

/* negate a decimal */
#define decimal_neg(dec) do { (dec)->sign^=1; } while(0)

/*
  conventions:

    decimal_smth() == 0     -- everything's ok
    decimal_smth() <= 1     -- result is usable, but precision loss is possible
    decimal_smth() <= 2     -- result can be unusable, most significant digits
                               could've been lost
    decimal_smth() >  2     -- no result was generated
*/

#define E_DEC_OK                0
#define E_DEC_TRUNCATED         1
#define E_DEC_OVERFLOW          2
#define E_DEC_DIV_ZERO          4
#define E_DEC_BAD_NUM           8
#define E_DEC_OOM              16

#define E_DEC_ERROR            31
#define E_DEC_FATAL_ERROR      30

#ifdef __cplusplus
}
#endif

#endif