cash.c

Go to the documentation of this file.

/*
 * cash.c
 * Written by D'Arcy J.M. Cain
 * darcy@druid.net
 * http://www.druid.net/darcy/
 *
 * Functions to allow input and output of money normally but store
 * and handle it as 64 bit ints
 *
 * A slightly modified version of this file and a discussion of the
 * workings can be found in the book "Software Solutions in C" by
 * Dale Schumacher, Academic Press, ISBN: 0-12-632360-7 except that
 * this version handles 64 bit numbers and so can hold values up to
 * $92,233,720,368,547,758.07.
 *
 * src/backend/utils/adt/cash.c
 */
 
#include "postgres.h"
 
#include <limits.h>
#include <ctype.h>
#include <math.h>
 
#include "common/int.h"
#include "libpq/pqformat.h"
#include "utils/builtins.h"
#include "utils/cash.h"
#include "utils/float.h"
#include "utils/numeric.h"
#include "utils/pg_locale.h"
 
 
/*************************************************************************
 * Private routines
 ************************************************************************/
 
static const char *
num_word(Cash value)
{
    static char buf[128];
    static const char *const small[] = {
        "zero", "one", "two", "three", "four", "five", "six", "seven",
        "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen",
        "fifteen", "sixteen", "seventeen", "eighteen", "nineteen", "twenty",
        "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
    };
    const char *const *big = small + 18;
    int         tu = value % 100;
 
    /* deal with the simple cases first */
    if (value <= 20)
        return small[value];
 
    /* is it an even multiple of 100? */
    if (!tu)
    {
        sprintf(buf, "%s hundred", small[value / 100]);
        return buf;
    }
 
    /* more than 99? */
    if (value > 99)
    {
        /* is it an even multiple of 10 other than 10? */
        if (value % 10 == 0 && tu > 10)
            sprintf(buf, "%s hundred %s",
                    small[value / 100], big[tu / 10]);
        else if (tu < 20)
            sprintf(buf, "%s hundred and %s",
                    small[value / 100], small[tu]);
        else
            sprintf(buf, "%s hundred %s %s",
                    small[value / 100], big[tu / 10], small[tu % 10]);
    }
    else
    {
        /* is it an even multiple of 10 other than 10? */
        if (value % 10 == 0 && tu > 10)
            sprintf(buf, "%s", big[tu / 10]);
        else if (tu < 20)
            sprintf(buf, "%s", small[tu]);
        else
            sprintf(buf, "%s %s", big[tu / 10], small[tu % 10]);
    }
 
    return buf;
}                               /* num_word() */
 
static inline Cash
cash_pl_cash(Cash c1, Cash c2)
{
    Cash        res;
 
    if (unlikely(pg_add_s64_overflow(c1, c2, &res)))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("money out of range")));
 
    return res;
}
 
static inline Cash
cash_mi_cash(Cash c1, Cash c2)
{
    Cash        res;
 
    if (unlikely(pg_sub_s64_overflow(c1, c2, &res)))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("money out of range")));
 
    return res;
}
 
static inline Cash
cash_mul_float8(Cash c, float8 f)
{
    float8      res = rint(float8_mul((float8) c, f));
 
    if (unlikely(isnan(res) || !FLOAT8_FITS_IN_INT64(res)))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("money out of range")));
 
    return (Cash) res;
}
 
static inline Cash
cash_div_float8(Cash c, float8 f)
{
    float8      res = rint(float8_div((float8) c, f));
 
    if (unlikely(isnan(res) || !FLOAT8_FITS_IN_INT64(res)))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("money out of range")));
 
    return (Cash) res;
}
 
static inline Cash
cash_mul_int64(Cash c, int64 i)
{
    Cash        res;
 
    if (unlikely(pg_mul_s64_overflow(c, i, &res)))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("money out of range")));
 
    return res;
}
 
static inline Cash
cash_div_int64(Cash c, int64 i)
{
    if (unlikely(i == 0))
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
 
    return c / i;
}
 
/* cash_in()
 * Convert a string to a cash data type.
 * Format is [$]###[,]###[.##]
 * Examples: 123.45 $123.45 $123,456.78
 *
 */
Datum
cash_in(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);
    Node       *escontext = fcinfo->context;
    Cash        result;
    Cash        value = 0;
    Cash        dec = 0;
    Cash        sgn = 1;
    bool        seen_dot = false;
    const char *s = str;
    int         fpoint;
    char        dsymbol;
    const char *ssymbol,
               *psymbol,
               *nsymbol,
               *csymbol;
    struct lconv *lconvert = PGLC_localeconv();
 
    /*
     * frac_digits will be CHAR_MAX in some locales, notably C.  However, just
     * testing for == CHAR_MAX is risky, because of compilers like gcc that
     * "helpfully" let you alter the platform-standard definition of whether
     * char is signed or not.  If we are so unfortunate as to get compiled
     * with a nonstandard -fsigned-char or -funsigned-char switch, then our
     * idea of CHAR_MAX will not agree with libc's. The safest course is not
     * to test for CHAR_MAX at all, but to impose a range check for plausible
     * frac_digits values.
     */
    fpoint = lconvert->frac_digits;
    if (fpoint < 0 || fpoint > 10)
        fpoint = 2;             /* best guess in this case, I think */
 
    /* we restrict dsymbol to be a single byte, but not the other symbols */
    if (*lconvert->mon_decimal_point != '\0' &&
        lconvert->mon_decimal_point[1] == '\0')
        dsymbol = *lconvert->mon_decimal_point;
    else
        dsymbol = '.';
    if (*lconvert->mon_thousands_sep != '\0')
        ssymbol = lconvert->mon_thousands_sep;
    else                        /* ssymbol should not equal dsymbol */
        ssymbol = (dsymbol != ',') ? "," : ".";
    csymbol = (*lconvert->currency_symbol != '\0') ? lconvert->currency_symbol : "$";
    psymbol = (*lconvert->positive_sign != '\0') ? lconvert->positive_sign : "+";
    nsymbol = (*lconvert->negative_sign != '\0') ? lconvert->negative_sign : "-";
 
#ifdef CASHDEBUG
    printf("cashin- precision '%d'; decimal '%c'; thousands '%s'; currency '%s'; positive '%s'; negative '%s'\n",
           fpoint, dsymbol, ssymbol, csymbol, psymbol, nsymbol);
#endif
 
    /* we need to add all sorts of checking here.  For now just */
    /* strip all leading whitespace and any leading currency symbol */
    while (isspace((unsigned char) *s))
        s++;
    if (strncmp(s, csymbol, strlen(csymbol)) == 0)
        s += strlen(csymbol);
    while (isspace((unsigned char) *s))
        s++;
 
#ifdef CASHDEBUG
    printf("cashin- string is '%s'\n", s);
#endif
 
    /* a leading minus or paren signifies a negative number */
    /* again, better heuristics needed */
    /* XXX - doesn't properly check for balanced parens - djmc */
    if (strncmp(s, nsymbol, strlen(nsymbol)) == 0)
    {
        sgn = -1;
        s += strlen(nsymbol);
    }
    else if (*s == '(')
    {
        sgn = -1;
        s++;
    }
    else if (strncmp(s, psymbol, strlen(psymbol)) == 0)
        s += strlen(psymbol);
 
#ifdef CASHDEBUG
    printf("cashin- string is '%s'\n", s);
#endif
 
    /* allow whitespace and currency symbol after the sign, too */
    while (isspace((unsigned char) *s))
        s++;
    if (strncmp(s, csymbol, strlen(csymbol)) == 0)
        s += strlen(csymbol);
    while (isspace((unsigned char) *s))
        s++;
 
#ifdef CASHDEBUG
    printf("cashin- string is '%s'\n", s);
#endif
 
    /*
     * We accumulate the absolute amount in "value" and then apply the sign at
     * the end.  (The sign can appear before or after the digits, so it would
     * be more complicated to do otherwise.)  Because of the larger range of
     * negative signed integers, we build "value" in the negative and then
     * flip the sign at the end, catching most-negative-number overflow if
     * necessary.
     */
 
    for (; *s; s++)
    {
        /*
         * We look for digits as long as we have found less than the required
         * number of decimal places.
         */
        if (isdigit((unsigned char) *s) && (!seen_dot || dec < fpoint))
        {
            int8        digit = *s - '0';
 
            if (pg_mul_s64_overflow(value, 10, &value) ||
                pg_sub_s64_overflow(value, digit, &value))
                ereturn(escontext, (Datum) 0,
                        (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                         errmsg("value \"%s\" is out of range for type %s",
                                str, "money")));
 
            if (seen_dot)
                dec++;
        }
        /* decimal point? then start counting fractions... */
        else if (*s == dsymbol && !seen_dot)
        {
            seen_dot = true;
        }
        /* ignore if "thousands" separator, else we're done */
        else if (strncmp(s, ssymbol, strlen(ssymbol)) == 0)
            s += strlen(ssymbol) - 1;
        else
            break;
    }
 
    /* round off if there's another digit */
    if (isdigit((unsigned char) *s) && *s >= '5')
    {
        /* remember we build the value in the negative */
        if (pg_sub_s64_overflow(value, 1, &value))
            ereturn(escontext, (Datum) 0,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("value \"%s\" is out of range for type %s",
                            str, "money")));
    }
 
    /* adjust for less than required decimal places */
    for (; dec < fpoint; dec++)
    {
        if (pg_mul_s64_overflow(value, 10, &value))
            ereturn(escontext, (Datum) 0,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("value \"%s\" is out of range for type %s",
                            str, "money")));
    }
 
    /*
     * should only be trailing digits followed by whitespace, right paren,
     * trailing sign, and/or trailing currency symbol
     */
    while (isdigit((unsigned char) *s))
        s++;
 
    while (*s)
    {
        if (isspace((unsigned char) *s) || *s == ')')
            s++;
        else if (strncmp(s, nsymbol, strlen(nsymbol)) == 0)
        {
            sgn = -1;
            s += strlen(nsymbol);
        }
        else if (strncmp(s, psymbol, strlen(psymbol)) == 0)
            s += strlen(psymbol);
        else if (strncmp(s, csymbol, strlen(csymbol)) == 0)
            s += strlen(csymbol);
        else
            ereturn(escontext, (Datum) 0,
                    (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                     errmsg("invalid input syntax for type %s: \"%s\"",
                            "money", str)));
    }
 
    /*
     * If the value is supposed to be positive, flip the sign, but check for
     * the most negative number.
     */
    if (sgn > 0)
    {
        if (value == PG_INT64_MIN)
            ereturn(escontext, (Datum) 0,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("value \"%s\" is out of range for type %s",
                            str, "money")));
        result = -value;
    }
    else
        result = value;
 
#ifdef CASHDEBUG
    printf("cashin- result is " INT64_FORMAT "\n", result);
#endif
 
    PG_RETURN_CASH(result);
}
 
 
/* cash_out()
 * Function to convert cash to a dollars and cents representation, using
 * the lc_monetary locale's formatting.
 */
Datum
cash_out(PG_FUNCTION_ARGS)
{
    Cash        value = PG_GETARG_CASH(0);
    char       *result;
    char        buf[128];
    char       *bufptr;
    int         digit_pos;
    int         points,
                mon_group;
    char        dsymbol;
    const char *ssymbol,
               *csymbol,
               *signsymbol;
    char        sign_posn,
                cs_precedes,
                sep_by_space;
    struct lconv *lconvert = PGLC_localeconv();
 
    /* see comments about frac_digits in cash_in() */
    points = lconvert->frac_digits;
    if (points < 0 || points > 10)
        points = 2;             /* best guess in this case, I think */
 
    /*
     * As with frac_digits, must apply a range check to mon_grouping to avoid
     * being fooled by variant CHAR_MAX values.
     */
    mon_group = *lconvert->mon_grouping;
    if (mon_group <= 0 || mon_group > 6)
        mon_group = 3;
 
    /* we restrict dsymbol to be a single byte, but not the other symbols */
    if (*lconvert->mon_decimal_point != '\0' &&
        lconvert->mon_decimal_point[1] == '\0')
        dsymbol = *lconvert->mon_decimal_point;
    else
        dsymbol = '.';
    if (*lconvert->mon_thousands_sep != '\0')
        ssymbol = lconvert->mon_thousands_sep;
    else                        /* ssymbol should not equal dsymbol */
        ssymbol = (dsymbol != ',') ? "," : ".";
    csymbol = (*lconvert->currency_symbol != '\0') ? lconvert->currency_symbol : "$";
 
    if (value < 0)
    {
        /* make the amount positive for digit-reconstruction loop */
        value = -value;
        /* set up formatting data */
        signsymbol = (*lconvert->negative_sign != '\0') ? lconvert->negative_sign : "-";
        sign_posn = lconvert->n_sign_posn;
        cs_precedes = lconvert->n_cs_precedes;
        sep_by_space = lconvert->n_sep_by_space;
    }
    else
    {
        signsymbol = lconvert->positive_sign;
        sign_posn = lconvert->p_sign_posn;
        cs_precedes = lconvert->p_cs_precedes;
        sep_by_space = lconvert->p_sep_by_space;
    }
 
    /* we build the digits+decimal-point+sep string right-to-left in buf[] */
    bufptr = buf + sizeof(buf) - 1;
    *bufptr = '\0';
 
    /*
     * Generate digits till there are no non-zero digits left and we emitted
     * at least one to the left of the decimal point.  digit_pos is the
     * current digit position, with zero as the digit just left of the decimal
     * point, increasing to the right.
     */
    digit_pos = points;
    do
    {
        if (points && digit_pos == 0)
        {
            /* insert decimal point, but not if value cannot be fractional */
            *(--bufptr) = dsymbol;
        }
        else if (digit_pos < 0 && (digit_pos % mon_group) == 0)
        {
            /* insert thousands sep, but only to left of radix point */
            bufptr -= strlen(ssymbol);
            memcpy(bufptr, ssymbol, strlen(ssymbol));
        }
 
        *(--bufptr) = ((uint64) value % 10) + '0';
        value = ((uint64) value) / 10;
        digit_pos--;
    } while (value || digit_pos >= 0);
 
    /*----------
     * Now, attach currency symbol and sign symbol in the correct order.
     *
     * The POSIX spec defines these values controlling this code:
     *
     * p/n_sign_posn:
     *  0   Parentheses enclose the quantity and the currency_symbol.
     *  1   The sign string precedes the quantity and the currency_symbol.
     *  2   The sign string succeeds the quantity and the currency_symbol.
     *  3   The sign string precedes the currency_symbol.
     *  4   The sign string succeeds the currency_symbol.
     *
     * p/n_cs_precedes: 0 means currency symbol after value, else before it.
     *
     * p/n_sep_by_space:
     *  0   No <space> separates the currency symbol and value.
     *  1   If the currency symbol and sign string are adjacent, a <space>
     *      separates them from the value; otherwise, a <space> separates
     *      the currency symbol from the value.
     *  2   If the currency symbol and sign string are adjacent, a <space>
     *      separates them; otherwise, a <space> separates the sign string
     *      from the value.
     *----------
     */
    switch (sign_posn)
    {
        case 0:
            if (cs_precedes)
                result = psprintf("(%s%s%s)",
                                  csymbol,
                                  (sep_by_space == 1) ? " " : "",
                                  bufptr);
            else
                result = psprintf("(%s%s%s)",
                                  bufptr,
                                  (sep_by_space == 1) ? " " : "",
                                  csymbol);
            break;
        case 1:
        default:
            if (cs_precedes)
                result = psprintf("%s%s%s%s%s",
                                  signsymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  csymbol,
                                  (sep_by_space == 1) ? " " : "",
                                  bufptr);
            else
                result = psprintf("%s%s%s%s%s",
                                  signsymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  bufptr,
                                  (sep_by_space == 1) ? " " : "",
                                  csymbol);
            break;
        case 2:
            if (cs_precedes)
                result = psprintf("%s%s%s%s%s",
                                  csymbol,
                                  (sep_by_space == 1) ? " " : "",
                                  bufptr,
                                  (sep_by_space == 2) ? " " : "",
                                  signsymbol);
            else
                result = psprintf("%s%s%s%s%s",
                                  bufptr,
                                  (sep_by_space == 1) ? " " : "",
                                  csymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  signsymbol);
            break;
        case 3:
            if (cs_precedes)
                result = psprintf("%s%s%s%s%s",
                                  signsymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  csymbol,
                                  (sep_by_space == 1) ? " " : "",
                                  bufptr);
            else
                result = psprintf("%s%s%s%s%s",
                                  bufptr,
                                  (sep_by_space == 1) ? " " : "",
                                  signsymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  csymbol);
            break;
        case 4:
            if (cs_precedes)
                result = psprintf("%s%s%s%s%s",
                                  csymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  signsymbol,
                                  (sep_by_space == 1) ? " " : "",
                                  bufptr);
            else
                result = psprintf("%s%s%s%s%s",
                                  bufptr,
                                  (sep_by_space == 1) ? " " : "",
                                  csymbol,
                                  (sep_by_space == 2) ? " " : "",
                                  signsymbol);
            break;
    }
 
    PG_RETURN_CSTRING(result);
}
 
/*
 *      cash_recv           - converts external binary format to cash
 */
Datum
cash_recv(PG_FUNCTION_ARGS)
{
    StringInfo  buf = (StringInfo) PG_GETARG_POINTER(0);
 
    PG_RETURN_CASH((Cash) pq_getmsgint64(buf));
}
 
/*
 *      cash_send           - converts cash to binary format
 */
Datum
cash_send(PG_FUNCTION_ARGS)
{
    Cash        arg1 = PG_GETARG_CASH(0);
    StringInfoData buf;
 
    pq_begintypsend(&buf);
    pq_sendint64(&buf, arg1);
    PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}
 
/*
 * Comparison functions
 */
 
Datum
cash_eq(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_BOOL(c1 == c2);
}
 
Datum
cash_ne(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_BOOL(c1 != c2);
}
 
Datum
cash_lt(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_BOOL(c1 < c2);
}
 
Datum
cash_le(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_BOOL(c1 <= c2);
}
 
Datum
cash_gt(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_BOOL(c1 > c2);
}
 
Datum
cash_ge(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_BOOL(c1 >= c2);
}
 
Datum
cash_cmp(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    if (c1 > c2)
        PG_RETURN_INT32(1);
    else if (c1 == c2)
        PG_RETURN_INT32(0);
    else
        PG_RETURN_INT32(-1);
}
 
 
/* cash_pl()
 * Add two cash values.
 */
Datum
cash_pl(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_pl_cash(c1, c2));
}
 
 
/* cash_mi()
 * Subtract two cash values.
 */
Datum
cash_mi(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_mi_cash(c1, c2));
}
 
 
/* cash_div_cash()
 * Divide cash by cash, returning float8.
 */
Datum
cash_div_cash(PG_FUNCTION_ARGS)
{
    Cash        dividend = PG_GETARG_CASH(0);
    Cash        divisor = PG_GETARG_CASH(1);
    float8      quotient;
 
    if (divisor == 0)
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
 
    quotient = (float8) dividend / (float8) divisor;
    PG_RETURN_FLOAT8(quotient);
}
 
 
/* cash_mul_flt8()
 * Multiply cash by float8.
 */
Datum
cash_mul_flt8(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    float8      f = PG_GETARG_FLOAT8(1);
 
    PG_RETURN_CASH(cash_mul_float8(c, f));
}
 
 
/* flt8_mul_cash()
 * Multiply float8 by cash.
 */
Datum
flt8_mul_cash(PG_FUNCTION_ARGS)
{
    float8      f = PG_GETARG_FLOAT8(0);
    Cash        c = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_mul_float8(c, f));
}
 
 
/* cash_div_flt8()
 * Divide cash by float8.
 */
Datum
cash_div_flt8(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    float8      f = PG_GETARG_FLOAT8(1);
 
    PG_RETURN_CASH(cash_div_float8(c, f));
}
 
 
/* cash_mul_flt4()
 * Multiply cash by float4.
 */
Datum
cash_mul_flt4(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    float4      f = PG_GETARG_FLOAT4(1);
 
    PG_RETURN_CASH(cash_mul_float8(c, (float8) f));
}
 
 
/* flt4_mul_cash()
 * Multiply float4 by cash.
 */
Datum
flt4_mul_cash(PG_FUNCTION_ARGS)
{
    float4      f = PG_GETARG_FLOAT4(0);
    Cash        c = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_mul_float8(c, (float8) f));
}
 
 
/* cash_div_flt4()
 * Divide cash by float4.
 *
 */
Datum
cash_div_flt4(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    float4      f = PG_GETARG_FLOAT4(1);
 
    PG_RETURN_CASH(cash_div_float8(c, (float8) f));
}
 
 
/* cash_mul_int8()
 * Multiply cash by int8.
 */
Datum
cash_mul_int8(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    int64       i = PG_GETARG_INT64(1);
 
    PG_RETURN_CASH(cash_mul_int64(c, i));
}
 
 
/* int8_mul_cash()
 * Multiply int8 by cash.
 */
Datum
int8_mul_cash(PG_FUNCTION_ARGS)
{
    int64       i = PG_GETARG_INT64(0);
    Cash        c = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_mul_int64(c, i));
}
 
/* cash_div_int8()
 * Divide cash by 8-byte integer.
 */
Datum
cash_div_int8(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    int64       i = PG_GETARG_INT64(1);
 
    PG_RETURN_CASH(cash_div_int64(c, i));
}
 
 
/* cash_mul_int4()
 * Multiply cash by int4.
 */
Datum
cash_mul_int4(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    int32       i = PG_GETARG_INT32(1);
 
    PG_RETURN_CASH(cash_mul_int64(c, (int64) i));
}
 
 
/* int4_mul_cash()
 * Multiply int4 by cash.
 */
Datum
int4_mul_cash(PG_FUNCTION_ARGS)
{
    int32       i = PG_GETARG_INT32(0);
    Cash        c = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_mul_int64(c, (int64) i));
}
 
 
/* cash_div_int4()
 * Divide cash by 4-byte integer.
 *
 */
Datum
cash_div_int4(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    int32       i = PG_GETARG_INT32(1);
 
    PG_RETURN_CASH(cash_div_int64(c, (int64) i));
}
 
 
/* cash_mul_int2()
 * Multiply cash by int2.
 */
Datum
cash_mul_int2(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    int16       s = PG_GETARG_INT16(1);
 
    PG_RETURN_CASH(cash_mul_int64(c, (int64) s));
}
 
/* int2_mul_cash()
 * Multiply int2 by cash.
 */
Datum
int2_mul_cash(PG_FUNCTION_ARGS)
{
    int16       s = PG_GETARG_INT16(0);
    Cash        c = PG_GETARG_CASH(1);
 
    PG_RETURN_CASH(cash_mul_int64(c, (int64) s));
}
 
/* cash_div_int2()
 * Divide cash by int2.
 *
 */
Datum
cash_div_int2(PG_FUNCTION_ARGS)
{
    Cash        c = PG_GETARG_CASH(0);
    int16       s = PG_GETARG_INT16(1);
 
    PG_RETURN_CASH(cash_div_int64(c, (int64) s));
}
 
/* cashlarger()
 * Return larger of two cash values.
 */
Datum
cashlarger(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
    Cash        result;
 
    result = (c1 > c2) ? c1 : c2;
 
    PG_RETURN_CASH(result);
}
 
/* cashsmaller()
 * Return smaller of two cash values.
 */
Datum
cashsmaller(PG_FUNCTION_ARGS)
{
    Cash        c1 = PG_GETARG_CASH(0);
    Cash        c2 = PG_GETARG_CASH(1);
    Cash        result;
 
    result = (c1 < c2) ? c1 : c2;
 
    PG_RETURN_CASH(result);
}
 
/* cash_words()
 * This converts an int4 as well but to a representation using words
 * Obviously way North American centric - sorry
 */
Datum
cash_words(PG_FUNCTION_ARGS)
{
    Cash        value = PG_GETARG_CASH(0);
    uint64      val;
    char        buf[256];
    char       *p = buf;
    Cash        m0;
    Cash        m1;
    Cash        m2;
    Cash        m3;
    Cash        m4;
    Cash        m5;
    Cash        m6;
 
    /* work with positive numbers */
    if (value < 0)
    {
        value = -value;
        strcpy(buf, "minus ");
        p += 6;
    }
    else
        buf[0] = '\0';
 
    /* Now treat as unsigned, to avoid trouble at INT_MIN */
    val = (uint64) value;
 
    m0 = val % INT64CONST(100); /* cents */
    m1 = (val / INT64CONST(100)) % 1000;    /* hundreds */
    m2 = (val / INT64CONST(100000)) % 1000; /* thousands */
    m3 = (val / INT64CONST(100000000)) % 1000;  /* millions */
    m4 = (val / INT64CONST(100000000000)) % 1000;   /* billions */
    m5 = (val / INT64CONST(100000000000000)) % 1000;    /* trillions */
    m6 = (val / INT64CONST(100000000000000000)) % 1000; /* quadrillions */
 
    if (m6)
    {
        strcat(buf, num_word(m6));
        strcat(buf, " quadrillion ");
    }
 
    if (m5)
    {
        strcat(buf, num_word(m5));
        strcat(buf, " trillion ");
    }
 
    if (m4)
    {
        strcat(buf, num_word(m4));
        strcat(buf, " billion ");
    }
 
    if (m3)
    {
        strcat(buf, num_word(m3));
        strcat(buf, " million ");
    }
 
    if (m2)
    {
        strcat(buf, num_word(m2));
        strcat(buf, " thousand ");
    }
 
    if (m1)
        strcat(buf, num_word(m1));
 
    if (!*p)
        strcat(buf, "zero");
 
    strcat(buf, (val / 100) == 1 ? " dollar and " : " dollars and ");
    strcat(buf, num_word(m0));
    strcat(buf, m0 == 1 ? " cent" : " cents");
 
    /* capitalize output */
    buf[0] = pg_toupper((unsigned char) buf[0]);
 
    /* return as text datum */
    PG_RETURN_TEXT_P(cstring_to_text(buf));
}
 
 
/* cash_numeric()
 * Convert cash to numeric.
 */
Datum
cash_numeric(PG_FUNCTION_ARGS)
{
    Cash        money = PG_GETARG_CASH(0);
    Datum       result;
    int         fpoint;
    struct lconv *lconvert = PGLC_localeconv();
 
    /* see comments about frac_digits in cash_in() */
    fpoint = lconvert->frac_digits;
    if (fpoint < 0 || fpoint > 10)
        fpoint = 2;
 
    /* convert the integral money value to numeric */
    result = NumericGetDatum(int64_to_numeric(money));
 
    /* scale appropriately, if needed */
    if (fpoint > 0)
    {
        int64       scale;
        int         i;
        Datum       numeric_scale;
        Datum       quotient;
 
        /* compute required scale factor */
        scale = 1;
        for (i = 0; i < fpoint; i++)
            scale *= 10;
        numeric_scale = NumericGetDatum(int64_to_numeric(scale));
 
        /*
         * Given integral inputs approaching INT64_MAX, select_div_scale()
         * might choose a result scale of zero, causing loss of fractional
         * digits in the quotient.  We can ensure an exact result by setting
         * the dscale of either input to be at least as large as the desired
         * result scale.  numeric_round() will do that for us.
         */
        numeric_scale = DirectFunctionCall2(numeric_round,
                                            numeric_scale,
                                            Int32GetDatum(fpoint));
 
        /* Now we can safely divide ... */
        quotient = DirectFunctionCall2(numeric_div, result, numeric_scale);
 
        /* ... and forcibly round to exactly the intended number of digits */
        result = DirectFunctionCall2(numeric_round,
                                     quotient,
                                     Int32GetDatum(fpoint));
    }
 
    PG_RETURN_DATUM(result);
}
 
/* numeric_cash()
 * Convert numeric to cash.
 */
Datum
numeric_cash(PG_FUNCTION_ARGS)
{
    Datum       amount = PG_GETARG_DATUM(0);
    Cash        result;
    int         fpoint;
    int64       scale;
    int         i;
    Datum       numeric_scale;
    struct lconv *lconvert = PGLC_localeconv();
 
    /* see comments about frac_digits in cash_in() */
    fpoint = lconvert->frac_digits;
    if (fpoint < 0 || fpoint > 10)
        fpoint = 2;
 
    /* compute required scale factor */
    scale = 1;
    for (i = 0; i < fpoint; i++)
        scale *= 10;
 
    /* multiply the input amount by scale factor */
    numeric_scale = NumericGetDatum(int64_to_numeric(scale));
    amount = DirectFunctionCall2(numeric_mul, amount, numeric_scale);
 
    /* note that numeric_int8 will round to nearest integer for us */
    result = DatumGetInt64(DirectFunctionCall1(numeric_int8, amount));
 
    PG_RETURN_CASH(result);
}
 
/* int4_cash()
 * Convert int4 (int) to cash
 */
Datum
int4_cash(PG_FUNCTION_ARGS)
{
    int32       amount = PG_GETARG_INT32(0);
    Cash        result;
    int         fpoint;
    int64       scale;
    int         i;
    struct lconv *lconvert = PGLC_localeconv();
 
    /* see comments about frac_digits in cash_in() */
    fpoint = lconvert->frac_digits;
    if (fpoint < 0 || fpoint > 10)
        fpoint = 2;
 
    /* compute required scale factor */
    scale = 1;
    for (i = 0; i < fpoint; i++)
        scale *= 10;
 
    /* compute amount * scale, checking for overflow */
    result = DatumGetInt64(DirectFunctionCall2(int8mul, Int64GetDatum(amount),
                                               Int64GetDatum(scale)));
 
    PG_RETURN_CASH(result);
}
 
/* int8_cash()
 * Convert int8 (bigint) to cash
 */
Datum
int8_cash(PG_FUNCTION_ARGS)
{
    int64       amount = PG_GETARG_INT64(0);
    Cash        result;
    int         fpoint;
    int64       scale;
    int         i;
    struct lconv *lconvert = PGLC_localeconv();
 
    /* see comments about frac_digits in cash_in() */
    fpoint = lconvert->frac_digits;
    if (fpoint < 0 || fpoint > 10)
        fpoint = 2;
 
    /* compute required scale factor */
    scale = 1;
    for (i = 0; i < fpoint; i++)
        scale *= 10;
 
    /* compute amount * scale, checking for overflow */
    result = DatumGetInt64(DirectFunctionCall2(int8mul, Int64GetDatum(amount),
                                               Int64GetDatum(scale)));
 
    PG_RETURN_CASH(result);
}