numeric.c

PostgreSQL7.4.6 for Linux

static void
dump_var(const char *str, NumericVar *var)
{
	int			i;

	printf("%s: VAR w=%d d=%d ", str, var->weight, var->dscale);
	switch (var->sign)
	{
		case NUMERIC_POS:
			printf("POS");
			break;
		case NUMERIC_NEG:
			printf("NEG");
			break;
		case NUMERIC_NAN:
			printf("NaN");
			break;
		default:
			printf("SIGN=0x%x", var->sign);
			break;
	}

	for (i = 0; i < var->ndigits; i++)
		printf(" %0*d", DEC_DIGITS, var->digits[i]);

	printf("\n");
}
#endif   /* NUMERIC_DEBUG */


/* ----------------------------------------------------------------------
 *
 * Local functions follow
 *
 * In general, these do not support NaNs --- callers must eliminate
 * the possibility of NaN first.  (make_result() is an exception.)
 *
 * ----------------------------------------------------------------------
 */


/*
 * alloc_var() -
 *
 *	Allocate a digit buffer of ndigits digits (plus a spare digit for rounding)
 */
static void
alloc_var(NumericVar *var, int ndigits)
{
	digitbuf_free(var->buf);
	var->buf = digitbuf_alloc(ndigits + 1);
	var->buf[0] = 0;			/* spare digit for rounding */
	var->digits = var->buf + 1;
	var->ndigits = ndigits;
}


/*
 * free_var() -
 *
 *	Return the digit buffer of a variable to the free pool
 */
static void
free_var(NumericVar *var)
{
	digitbuf_free(var->buf);
	var->buf = NULL;
	var->digits = NULL;
	var->sign = NUMERIC_NAN;
}


/*
 * zero_var() -
 *
 *	Set a variable to ZERO.
 *	Note: its dscale is not touched.
 */
static void
zero_var(NumericVar *var)
{
	digitbuf_free(var->buf);
	var->buf = NULL;
	var->digits = NULL;
	var->ndigits = 0;
	var->weight = 0;			/* by convention; doesn't really matter */
	var->sign = NUMERIC_POS;	/* anything but NAN... */
}


/*
 * set_var_from_str()
 *
 *	Parse a string and put the number into a variable
 */
static void
set_var_from_str(const char *str, NumericVar *dest)
{
	const char *cp = str;
	bool		have_dp = FALSE;
	int			i;
	unsigned char *decdigits;
	int			sign = NUMERIC_POS;
	int			dweight = -1;
	int			ddigits;
	int			dscale = 0;
	int			weight;
	int			ndigits;
	int			offset;
	NumericDigit *digits;

	/*
	 * We first parse the string to extract decimal digits and determine
	 * the correct decimal weight.	Then convert to NBASE representation.
	 */

	/* skip leading spaces */
	while (*cp)
	{
		if (!isspace((unsigned char) *cp))
			break;
		cp++;
	}

	switch (*cp)
	{
		case '+':
			sign = NUMERIC_POS;
			cp++;
			break;

		case '-':
			sign = NUMERIC_NEG;
			cp++;
			break;
	}

	if (*cp == '.')
	{
		have_dp = TRUE;
		cp++;
	}

	if (!isdigit((unsigned char) *cp))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
			   errmsg("invalid input syntax for type numeric: \"%s\"", str)));

	decdigits = (unsigned char *) palloc(strlen(cp) + DEC_DIGITS * 2);

	/* leading padding for digit alignment later */
	memset(decdigits, 0, DEC_DIGITS);
	i = DEC_DIGITS;

	while (*cp)
	{
		if (isdigit((unsigned char) *cp))
		{
			decdigits[i++] = *cp++ - '0';
			if (!have_dp)
				dweight++;
			else
				dscale++;
		}
		else if (*cp == '.')
		{
			if (have_dp)
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
					   errmsg("invalid input syntax for type numeric: \"%s\"",
							  str)));
			have_dp = TRUE;
			cp++;
		}
		else
			break;
	}

	ddigits = i - DEC_DIGITS;
	/* trailing padding for digit alignment later */
	memset(decdigits + i, 0, DEC_DIGITS - 1);

	/* Handle exponent, if any */
	if (*cp == 'e' || *cp == 'E')
	{
		long		exponent;
		char	   *endptr;

		cp++;
		exponent = strtol(cp, &endptr, 10);
		if (endptr == cp)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
					 errmsg("invalid input syntax for type numeric: \"%s\"",
							str)));
		cp = endptr;
		if (exponent > NUMERIC_MAX_PRECISION ||
			exponent < -NUMERIC_MAX_PRECISION)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
					 errmsg("invalid input syntax for type numeric: \"%s\"",
							str)));
		dweight += (int) exponent;
		dscale -= (int) exponent;
		if (dscale < 0)
			dscale = 0;
	}

	/* Should be nothing left but spaces */
	while (*cp)
	{
		if (!isspace((unsigned char) *cp))
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
					 errmsg("invalid input syntax for type numeric: \"%s\"",
							str)));
		cp++;
	}

	/*
	 * Okay, convert pure-decimal representation to base NBASE.  First we
	 * need to determine the converted weight and ndigits.	offset is the
	 * number of decimal zeroes to insert before the first given digit to
	 * have a correctly aligned first NBASE digit.
	 */
	if (dweight >= 0)
		weight = (dweight + 1 + DEC_DIGITS - 1) / DEC_DIGITS - 1;
	else
		weight = -((-dweight - 1) / DEC_DIGITS + 1);
	offset = (weight + 1) * DEC_DIGITS - (dweight + 1);
	ndigits = (ddigits + offset + DEC_DIGITS - 1) / DEC_DIGITS;

	alloc_var(dest, ndigits);
	dest->sign = sign;
	dest->weight = weight;
	dest->dscale = dscale;

	i = DEC_DIGITS - offset;
	digits = dest->digits;

	while (ndigits-- > 0)
	{
#if DEC_DIGITS == 4
		*digits++ = ((decdigits[i] * 10 + decdigits[i + 1]) * 10 +
					 decdigits[i + 2]) * 10 + decdigits[i + 3];
#elif DEC_DIGITS == 2
		*digits++ = decdigits[i] * 10 + decdigits[i + 1];
#elif DEC_DIGITS == 1
		*digits++ = decdigits[i];
#else
#error unsupported NBASE
#endif
		i += DEC_DIGITS;
	}

	pfree(decdigits);

	/* Strip any leading/trailing zeroes, and normalize weight if zero */
	strip_var(dest);
}


/*
 * set_var_from_num() -
 *
 *	Convert the packed db format into a variable
 */
static void
set_var_from_num(Numeric num, NumericVar *dest)
{
	int			ndigits;

	ndigits = (num->varlen - NUMERIC_HDRSZ) / sizeof(NumericDigit);

	alloc_var(dest, ndigits);

	dest->weight = num->n_weight;
	dest->sign = NUMERIC_SIGN(num);
	dest->dscale = NUMERIC_DSCALE(num);

	memcpy(dest->digits, num->n_data, ndigits * sizeof(NumericDigit));
}


/*
 * set_var_from_var() -
 *
 *	Copy one variable into another
 */
static void
set_var_from_var(NumericVar *value, NumericVar *dest)
{
	NumericDigit *newbuf;

	newbuf = digitbuf_alloc(value->ndigits + 1);
	newbuf[0] = 0;				/* spare digit for rounding */
	memcpy(newbuf + 1, value->digits, value->ndigits * sizeof(NumericDigit));

	digitbuf_free(dest->buf);

	memcpy(dest, value, sizeof(NumericVar));
	dest->buf = newbuf;
	dest->digits = newbuf + 1;
}


/*
 * get_str_from_var() -
 *
 *	Convert a var to text representation (guts of numeric_out).
 *	CAUTION: var's contents may be modified by rounding!
 *	Returns a palloc'd string.
 */
static char *
get_str_from_var(NumericVar *var, int dscale)
{
	char	   *str;
	char	   *cp;
	char	   *endcp;
	int			i;
	int			d;
	NumericDigit dig;

#if DEC_DIGITS > 1
	NumericDigit d1;
#endif

	if (dscale < 0)
		dscale = 0;

	/*
	 * Check if we must round up before printing the value and do so.
	 */
	round_var(var, dscale);

	/*
	 * Allocate space for the result.
	 *
	 * i is set to to # of decimal digits before decimal point. dscale is the
	 * # of decimal digits we will print after decimal point. We may
	 * generate as many as DEC_DIGITS-1 excess digits at the end, and in
	 * addition we need room for sign, decimal point, null terminator.
	 */
	i = (var->weight + 1) * DEC_DIGITS;
	if (i <= 0)
		i = 1;

	str = palloc(i + dscale + DEC_DIGITS + 2);
	cp = str;

	/*
	 * Output a dash for negative values
	 */
	if (var->sign == NUMERIC_NEG)
		*cp++ = '-';

	/*
	 * Output all digits before the decimal point
	 */
	if (var->weight < 0)
	{
		d = var->weight + 1;
		*cp++ = '0';
	}
	else
	{
		for (d = 0; d <= var->weight; d++)
		{
			dig = (d < var->ndigits) ? var->digits[d] : 0;
			/* In the first digit, suppress extra leading decimal zeroes */
#if DEC_DIGITS == 4
			{
				bool		putit = (d > 0);

				d1 = dig / 1000;
				dig -= d1 * 1000;
				putit |= (d1 > 0);
				if (putit)
					*cp++ = d1 + '0';
				d1 = dig / 100;
				dig -= d1 * 100;
				putit |= (d1 > 0);
				if (putit)
					*cp++ = d1 + '0';
				d1 = dig / 10;
				dig -= d1 * 10;
				putit |= (d1 > 0);
				if (putit)
					*cp++ = d1 + '0';
				*cp++ = dig + '0';
			}
#elif DEC_DIGITS == 2
			d1 = dig / 10;
			dig -= d1 * 10;
			if (d1 > 0 || d > 0)
				*cp++ = d1 + '0';
			*cp++ = dig + '0';
#elif DEC_DIGITS == 1
			*cp++ = dig + '0';
#else
#error unsupported NBASE
#endif
		}
	}

	/*
	 * If requested, output a decimal point and all the digits that follow
	 * it.	We initially put out a multiple of DEC_DIGITS digits, then
	 * truncate if needed.
	 */
	if (dscale > 0)
	{
		*cp++ = '.';
		endcp = cp + dscale;
		for (i = 0; i < dscale; d++, i += DEC_DIGITS)
		{
			dig = (d >= 0 && d < var->ndigits) ? var->digits[d] : 0;
#if DEC_DIGITS == 4
			d1 = dig / 1000;
			dig -= d1 * 1000;
			*cp++ = d1 + '0';
			d1 = dig / 100;
			dig -= d1 * 100;
			*cp++ = d1 + '0';
			d1 = dig / 10;
			dig -= d1 * 10;
			*cp++ = d1 + '0';
			*cp++ = dig + '0';
#elif DEC_DIGITS == 2
			d1 = dig / 10;
			dig -= d1 * 10;
			*cp++ = d1 + '0';
			*cp++ = dig + '0';
#elif DEC_DIGITS == 1
			*cp++ = dig + '0';
#else
#error unsupported NBASE
#endif
		}
		cp = endcp;
	}

	/*
	 * terminate the string and return it
	 */
	*cp = '\0';
	return str;
}


/*
 * make_result() -
 *
 *	Create the packed db numeric format in palloc()'d memory from
 *	a variable.
 */
static Numeric
make_result(NumericVar *var)
{
	Numeric		result;
	NumericDigit *digits = var->digits;
	int			weight = var->weight;
	int			sign = var->sign;
	int			n;
	Size		len;

	if (sign == NUMERIC_NAN)
	{
		result = (Numeric) palloc(NUMERIC_HDRSZ);

		result->varlen = NUMERIC_HDRSZ;
		result->n_weight = 0;
		result->n_sign_dscale = NUMERIC_NAN;

		dump_numeric("make_result()", result);
		return result;
	}

	n = var->ndigits;

	/* truncate leading zeroes */
	while (n > 0 && *digits == 0)
	{
		digits++;
		weight--;
		n--;
	}
	/* truncate trailing zeroes */
	while (n > 0 && digits[n - 1] == 0)
		n--;

	/* If zero result, force to weight=0 and positive sign */
	if (n == 0)
	{
		weight = 0;
		sign = NUMERIC_POS;
	}

	/* Build the result */
	len = NUMERIC_HDRSZ + n * sizeof(NumericDigit);
	result = (Numeric) palloc(len);
	result->varlen = len;
	result->n_weight = weight;
	result->n_sign_dscale = sign | (var->dscale & NUMERIC_DSCALE_MASK);

	memcpy(result->n_data, digits, n * sizeof(NumericDigit));

	/* Check for overflow of int16 fields */
	if (result->n_weight != weight ||
		NUMERIC_DSCALE(result) != var->dscale)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("value overflows numeric format")));

	dump_numeric("make_result()", result);
	return result;
}


/*
 * apply_typmod() -
 *
 *	Do bounds checking and rounding according to the attributes
 *	typmod field.
 */
static void
apply_typmod(NumericVar *var, int32 typmod)
{
	int			precision;
	int			scale;
	int			maxdigits;
	int			ddigits;
	int			i;

	/* Do nothing if we have a default typmod (-1) */
	if (typmod < (int32) (VARHDRSZ))
		return;

	typmod -= VARHDRSZ;
	precision = (typmod >> 16) & 0xffff;
	scale = typmod & 0xffff;
	maxdigits = precision - scale;

	/* Round to target scale (and set var->dscale) */
	round_var(var, scale);

	/*
	 * Check for overflow - note we can't do this before rounding, because
	 * rounding could raise the weight.  Also note that the var's weight
	 * could be inflated by leading zeroes, which will be stripped before
	 * storage but perhaps might not have been yet. In any case, we must
	 * recognize a true zero, whose weight doesn't mean anything.
	 */
	ddigits = (var->weight + 1) * DEC_DIGITS;
	if (ddigits > maxdigits)
	{
		/* Determine true weight; and check for all-zero result */
		for (i = 0; i < var->ndigits; i++)
		{
			NumericDigit dig = var->digits[i];

			if (dig)
			{
				/* Adjust for any high-order decimal zero digits */
#if DEC_DIGITS == 4
				if (dig < 10)
					ddigits -= 3;
				else if (dig < 100)
					ddigits -= 2;
				else if (dig < 1000)
					ddigits -= 1;
#elif DEC_DIGITS == 2
				if (dig < 10)
					ddigits -= 1;
#elif DEC_DIGITS == 1
				/* no adjustment */
#else
#error unsupported NBASE
#endif
				if (ddigits > maxdigits)
					ereport(ERROR,
							(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
							 errmsg("numeric field overflow"),
							 errdetail("The absolute value is greater than or equal to 10^%d for field with precision %d, scale %d.",
									   ddigits - 1, precision, scale)));
				break;
			}
			ddigits -= DEC_DIGITS;
		}
	}
}

/*
 * Convert numeric to int8, rounding if needed.
 *
 * If overflow, return FALSE (no error