cash.c

PostgreSQL7.4.6 for Linux

/*
 * cash.c
 * Written by D'Arcy J.M. Cain
 *
 * Functions to allow input and output of money normally but store
 * and handle it as int4s
 *
 * 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.
 *
 * $Header: /cvsroot/pgsql/src/backend/utils/adt/cash.c,v 1.61 2003/09/25 06:58:03 petere Exp $
 */

#include "postgres.h"

#include <limits.h>
#include <ctype.h>
#include <math.h>
#include <locale.h>

#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/cash.h"
#include "utils/pg_locale.h"


static const char *num_word(Cash value);

/* when we go to 64 bit values we will have to modify this */
#define CASH_BUFSZ		24

#define TERMINATOR		(CASH_BUFSZ - 1)
#define LAST_PAREN		(TERMINATOR - 1)
#define LAST_DIGIT		(LAST_PAREN - 1)


/*
 * Cash is a pass-by-ref SQL type, so we must pass and return pointers.
 * These macros and support routine hide the pass-by-refness.
 */
#define PG_GETARG_CASH(n)  (* ((Cash *) PG_GETARG_POINTER(n)))
#define PG_RETURN_CASH(x)  return CashGetDatum(x)

static Datum
CashGetDatum(Cash value)
{
	Cash	   *result = (Cash *) palloc(sizeof(Cash));

	*result = value;
	return PointerGetDatum(result);
}


/* cash_in()
 * Convert a string to a cash data type.
 * Format is [$]###[,]###[.##]
 * Examples: 123.45 $123.45 $123,456.78
 *
 * This is currently implemented as a 32-bit integer.
 * XXX HACK It looks as though some of the symbols for
 *	monetary values returned by localeconv() can be multiple
 *	bytes/characters. This code assumes one byte only. - tgl 97/04/14
 * XXX UNHACK Allow the currency symbol to be multibyte.
 *	- thomas 1998-03-01
 */
Datum
cash_in(PG_FUNCTION_ARGS)
{
	char	   *str = PG_GETARG_CSTRING(0);
	Cash		result;
	Cash		value = 0;
	Cash		dec = 0;
	Cash		sgn = 1;
	int			seen_dot = 0;
	const char *s = str;
	int			fpoint;
	char	   *csymbol;
	char		dsymbol,
				ssymbol,
				psymbol,
			   *nsymbol;

	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 */

	dsymbol = ((*lconvert->mon_decimal_point != '\0') ? *lconvert->mon_decimal_point : '.');
	ssymbol = ((*lconvert->mon_thousands_sep != '\0') ? *lconvert->mon_thousands_sep : ',');
	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 '%c'; currency '%s'; positive '%c'; 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);

#ifdef CASHDEBUG
	printf("cashin- string is '%s'\n", s);
#endif

	/* a leading minus or paren signifies a negative number */
	/* again, better heuristics needed */
	if (strncmp(s, nsymbol, strlen(nsymbol)) == 0)
	{
		sgn = -1;
		s += strlen(nsymbol);
#ifdef CASHDEBUG
		printf("cashin- negative symbol; string is '%s'\n", s);
#endif
	}
	else if (*s == '(')
	{
		sgn = -1;
		s++;

	}
	else if (*s == psymbol)
		s++;

#ifdef CASHDEBUG
	printf("cashin- string is '%s'\n", s);
#endif

	while (isspace((unsigned char) *s))
		s++;
	if (strncmp(s, csymbol, strlen(csymbol)) == 0)
		s += strlen(csymbol);

#ifdef CASHDEBUG
	printf("cashin- string is '%s'\n", s);
#endif

	for (;; s++)
	{
		/* we look for digits as int4 as we have less */
		/* than the required number of decimal places */
		if (isdigit((unsigned char) *s) && dec < fpoint)
		{
			value = (value * 10) + *s - '0';

			if (seen_dot)
				dec++;

			/* decimal point? then start counting fractions... */
		}
		else if (*s == dsymbol && !seen_dot)
		{
			seen_dot = 1;

			/* "thousands" separator? then skip... */
		}
		else if (*s == ssymbol)
		{

		}
		else
		{
			/* round off */
			if (isdigit((unsigned char) *s) && *s >= '5')
				value++;

			/* adjust for less than required decimal places */
			for (; dec < fpoint; dec++)
				value *= 10;

			break;
		}
	}

	while (isspace((unsigned char) *s) || *s == '0' || *s == ')')
		s++;

	if (*s != '\0')
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
				 errmsg("invalid input syntax for type money: \"%s\"", str)));

	result = (value * sgn);

#ifdef CASHDEBUG
	printf("cashin- result is %d\n", result);
#endif

	PG_RETURN_CASH(result);
}


/* cash_out()
 * Function to convert cash to a dollars and cents representation.
 * XXX HACK This code appears to assume US conventions for
 *	positive-valued amounts. - tgl 97/04/14
 */
Datum
cash_out(PG_FUNCTION_ARGS)
{
	Cash		value = PG_GETARG_CASH(0);
	char	   *result;
	char		buf[CASH_BUFSZ];
	int			minus = 0;
	int			count = LAST_DIGIT;
	int			point_pos;
	int			comma_position = 0;
	int			points,
				mon_group;
	char		comma;
	char	   *csymbol,
				dsymbol,
			   *nsymbol;
	char		convention;

	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;

	comma = ((*lconvert->mon_thousands_sep != '\0') ? *lconvert->mon_thousands_sep : ',');
	convention = lconvert->n_sign_posn;
	dsymbol = ((*lconvert->mon_decimal_point != '\0') ? *lconvert->mon_decimal_point : '.');
	csymbol = ((*lconvert->currency_symbol != '\0') ? lconvert->currency_symbol : "$");
	nsymbol = ((*lconvert->negative_sign != '\0') ? lconvert->negative_sign : "-");

	point_pos = LAST_DIGIT - points;

	/* allow more than three decimal points and separate them */
	if (comma)
	{
		point_pos -= (points - 1) / mon_group;
		comma_position = point_pos % (mon_group + 1);
	}

	/* we work with positive amounts and add the minus sign at the end */
	if (value < 0)
	{
		minus = 1;
		value = -value;
	}

	/* allow for trailing negative strings */
	MemSet(buf, ' ', CASH_BUFSZ);
	buf[TERMINATOR] = buf[LAST_PAREN] = '\0';

	while (value || count > (point_pos - 2))
	{
		if (points && count == point_pos)
			buf[count--] = dsymbol;
		else if (comma && count % (mon_group + 1) == comma_position)
			buf[count--] = comma;

		buf[count--] = ((unsigned int) value % 10) + '0';
		value = ((unsigned int) value) / 10;
	}

	strncpy((buf + count - strlen(csymbol) + 1), csymbol, strlen(csymbol));
	count -= strlen(csymbol) - 1;

	if (buf[LAST_DIGIT] == ',')
		buf[LAST_DIGIT] = buf[LAST_PAREN];

	/* see if we need to signify negative amount */
	if (minus)
	{
		if (!PointerIsValid(result = palloc(CASH_BUFSZ + 2 - count + strlen(nsymbol))))
			ereport(ERROR,
					(errcode(ERRCODE_OUT_OF_MEMORY),
					 errmsg("out of memory")));

		/* Position code of 0 means use parens */
		if (convention == 0)
			sprintf(result, "(%s)", buf + count);
		else if (convention == 2)
			sprintf(result, "%s%s", buf + count, nsymbol);
		else
			sprintf(result, "%s%s", nsymbol, buf + count);
	}
	else
	{
		if (!PointerIsValid(result = palloc(CASH_BUFSZ + 2 - count)))
			ereport(ERROR,
					(errcode(ERRCODE_OUT_OF_MEMORY),
					 errmsg("out of memory")));

		strcpy(result, buf + count);
	}

	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_getmsgint(buf, sizeof(Cash)));
}

/*
 *		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_sendint(&buf, arg1, sizeof(Cash));
	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);