varlena.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int32		result;

	result = text_cmp(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_INT32(result);
}


Datum
text_larger(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	text	   *result;

	result = ((text_cmp(arg1, arg2) > 0) ? arg1 : arg2);

	PG_RETURN_TEXT_P(result);
}

Datum
text_smaller(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	text	   *result;

	result = ((text_cmp(arg1, arg2) < 0) ? arg1 : arg2);

	PG_RETURN_TEXT_P(result);
}


/*
 * The following operators support character-by-character comparison
 * of text data types, to allow building indexes suitable for LIKE
 * clauses.
 */

static int
internal_text_pattern_compare(text *arg1, text *arg2)
{
	int			result;

	result = memcmp(VARDATA(arg1), VARDATA(arg2),
					Min(VARSIZE(arg1), VARSIZE(arg2)) - VARHDRSZ);
	if (result != 0)
		return result;
	else if (VARSIZE(arg1) < VARSIZE(arg2))
		return -1;
	else if (VARSIZE(arg1) > VARSIZE(arg2))
		return 1;
	else
		return 0;
}


Datum
text_pattern_lt(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_BOOL(result < 0);
}


Datum
text_pattern_le(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_BOOL(result <= 0);
}


Datum
text_pattern_eq(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	if (VARSIZE(arg1) != VARSIZE(arg2))
		result = 1;
	else
		result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_BOOL(result == 0);
}


Datum
text_pattern_ge(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_BOOL(result >= 0);
}


Datum
text_pattern_gt(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_BOOL(result > 0);
}


Datum
text_pattern_ne(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	if (VARSIZE(arg1) != VARSIZE(arg2))
		result = 1;
	else
		result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_BOOL(result != 0);
}


Datum
bttext_pattern_cmp(PG_FUNCTION_ARGS)
{
	text	   *arg1 = PG_GETARG_TEXT_P(0);
	text	   *arg2 = PG_GETARG_TEXT_P(1);
	int			result;

	result = internal_text_pattern_compare(arg1, arg2);

	PG_FREE_IF_COPY(arg1, 0);
	PG_FREE_IF_COPY(arg2, 1);

	PG_RETURN_INT32(result);
}


/*-------------------------------------------------------------
 * byteaoctetlen
 *
 * get the number of bytes contained in an instance of type 'bytea'
 *-------------------------------------------------------------
 */
Datum
byteaoctetlen(PG_FUNCTION_ARGS)
{
	Datum		str = PG_GETARG_DATUM(0);

	/* We need not detoast the input at all */
	PG_RETURN_INT32(toast_raw_datum_size(str) - VARHDRSZ);
}

/*
 * byteacat -
 *	  takes two bytea* and returns a bytea* that is the concatenation of
 *	  the two.
 *
 * Cloned from textcat and modified as required.
 */
Datum
byteacat(PG_FUNCTION_ARGS)
{
	bytea	   *t1 = PG_GETARG_BYTEA_P(0);
	bytea	   *t2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2,
				len;
	bytea	   *result;
	char	   *ptr;

	len1 = VARSIZE(t1) - VARHDRSZ;
	if (len1 < 0)
		len1 = 0;

	len2 = VARSIZE(t2) - VARHDRSZ;
	if (len2 < 0)
		len2 = 0;

	len = len1 + len2 + VARHDRSZ;
	result = (bytea *) palloc(len);

	/* Set size of result string... */
	VARATT_SIZEP(result) = len;

	/* Fill data field of result string... */
	ptr = VARDATA(result);
	if (len1 > 0)
		memcpy(ptr, VARDATA(t1), len1);
	if (len2 > 0)
		memcpy(ptr + len1, VARDATA(t2), len2);

	PG_RETURN_BYTEA_P(result);
}

#define PG_STR_GET_BYTEA(str_) \
	DatumGetByteaP(DirectFunctionCall1(byteain, CStringGetDatum(str_)))
/*
 * bytea_substr()
 * Return a substring starting at the specified position.
 * Cloned from text_substr and modified as required.
 *
 * Input:
 *	- string
 *	- starting position (is one-based)
 *	- string length (optional)
 *
 * If the starting position is zero or less, then return from the start of the string
 * adjusting the length to be consistent with the "negative start" per SQL92.
 * If the length is less than zero, an ERROR is thrown. If no third argument
 * (length) is provided, the length to the end of the string is assumed.
 */
Datum
bytea_substr(PG_FUNCTION_ARGS)
{
	int			S = PG_GETARG_INT32(1); /* start position */
	int			S1;				/* adjusted start position */
	int			L1;				/* adjusted substring length */

	S1 = Max(S, 1);

	if (fcinfo->nargs == 2)
	{
		/*
		 * Not passed a length - PG_GETARG_BYTEA_P_SLICE() grabs everything to
		 * the end of the string if we pass it a negative value for length.
		 */
		L1 = -1;
	}
	else
	{
		/* end position */
		int			E = S + PG_GETARG_INT32(2);

		/*
		 * A negative value for L is the only way for the end position to be
		 * before the start. SQL99 says to throw an error.
		 */
		if (E < S)
			ereport(ERROR,
					(errcode(ERRCODE_SUBSTRING_ERROR),
					 errmsg("negative substring length not allowed")));

		/*
		 * A zero or negative value for the end position can happen if the
		 * start was negative or one. SQL99 says to return a zero-length
		 * string.
		 */
		if (E < 1)
			PG_RETURN_BYTEA_P(PG_STR_GET_BYTEA(""));

		L1 = E - S1;
	}

	/*
	 * If the start position is past the end of the string, SQL99 says to
	 * return a zero-length string -- PG_GETARG_TEXT_P_SLICE() will do that
	 * for us. Convert to zero-based starting position
	 */
	PG_RETURN_BYTEA_P(PG_GETARG_BYTEA_P_SLICE(0, S1 - 1, L1));
}

/*
 * bytea_substr_no_len -
 *	  Wrapper to avoid opr_sanity failure due to
 *	  one function accepting a different number of args.
 */
Datum
bytea_substr_no_len(PG_FUNCTION_ARGS)
{
	return bytea_substr(fcinfo);
}

/*
 * byteapos -
 *	  Return the position of the specified substring.
 *	  Implements the SQL92 POSITION() function.
 * Cloned from textpos and modified as required.
 */
Datum
byteapos(PG_FUNCTION_ARGS)
{
	bytea	   *t1 = PG_GETARG_BYTEA_P(0);
	bytea	   *t2 = PG_GETARG_BYTEA_P(1);
	int			pos;
	int			px,
				p;
	int			len1,
				len2;
	char	   *p1,
			   *p2;

	if (VARSIZE(t2) <= VARHDRSZ)
		PG_RETURN_INT32(1);		/* result for empty pattern */

	len1 = VARSIZE(t1) - VARHDRSZ;
	len2 = VARSIZE(t2) - VARHDRSZ;

	p1 = VARDATA(t1);
	p2 = VARDATA(t2);

	pos = 0;
	px = (len1 - len2);
	for (p = 0; p <= px; p++)
	{
		if ((*p2 == *p1) && (memcmp(p1, p2, len2) == 0))
		{
			pos = p + 1;
			break;
		};
		p1++;
	};

	PG_RETURN_INT32(pos);
}

/*-------------------------------------------------------------
 * byteaGetByte
 *
 * this routine treats "bytea" as an array of bytes.
 * It returns the Nth byte (a number between 0 and 255).
 *-------------------------------------------------------------
 */
Datum
byteaGetByte(PG_FUNCTION_ARGS)
{
	bytea	   *v = PG_GETARG_BYTEA_P(0);
	int32		n = PG_GETARG_INT32(1);
	int			len;
	int			byte;

	len = VARSIZE(v) - VARHDRSZ;

	if (n < 0 || n >= len)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("index %d out of valid range, 0..%d",
						n, len - 1)));

	byte = ((unsigned char *) VARDATA(v))[n];

	PG_RETURN_INT32(byte);
}

/*-------------------------------------------------------------
 * byteaGetBit
 *
 * This routine treats a "bytea" type like an array of bits.
 * It returns the value of the Nth bit (0 or 1).
 *
 *-------------------------------------------------------------
 */
Datum
byteaGetBit(PG_FUNCTION_ARGS)
{
	bytea	   *v = PG_GETARG_BYTEA_P(0);
	int32		n = PG_GETARG_INT32(1);
	int			byteNo,
				bitNo;
	int			len;
	int			byte;

	len = VARSIZE(v) - VARHDRSZ;

	if (n < 0 || n >= len * 8)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("index %d out of valid range, 0..%d",
						n, len * 8 - 1)));

	byteNo = n / 8;
	bitNo = n % 8;

	byte = ((unsigned char *) VARDATA(v))[byteNo];

	if (byte & (1 << bitNo))
		PG_RETURN_INT32(1);
	else
		PG_RETURN_INT32(0);
}

/*-------------------------------------------------------------
 * byteaSetByte
 *
 * Given an instance of type 'bytea' creates a new one with
 * the Nth byte set to the given value.
 *
 *-------------------------------------------------------------
 */
Datum
byteaSetByte(PG_FUNCTION_ARGS)
{
	bytea	   *v = PG_GETARG_BYTEA_P(0);
	int32		n = PG_GETARG_INT32(1);
	int32		newByte = PG_GETARG_INT32(2);
	int			len;
	bytea	   *res;

	len = VARSIZE(v) - VARHDRSZ;

	if (n < 0 || n >= len)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("index %d out of valid range, 0..%d",
						n, len - 1)));

	/*
	 * Make a copy of the original varlena.
	 */
	res = (bytea *) palloc(VARSIZE(v));
	memcpy((char *) res, (char *) v, VARSIZE(v));

	/*
	 * Now set the byte.
	 */
	((unsigned char *) VARDATA(res))[n] = newByte;

	PG_RETURN_BYTEA_P(res);
}

/*-------------------------------------------------------------
 * byteaSetBit
 *
 * Given an instance of type 'bytea' creates a new one with
 * the Nth bit set to the given value.
 *
 *-------------------------------------------------------------
 */
Datum
byteaSetBit(PG_FUNCTION_ARGS)
{
	bytea	   *v = PG_GETARG_BYTEA_P(0);
	int32		n = PG_GETARG_INT32(1);
	int32		newBit = PG_GETARG_INT32(2);
	bytea	   *res;
	int			len;
	int			oldByte,
				newByte;
	int			byteNo,
				bitNo;

	len = VARSIZE(v) - VARHDRSZ;

	if (n < 0 || n >= len * 8)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("index %d out of valid range, 0..%d",
						n, len * 8 - 1)));

	byteNo = n / 8;
	bitNo = n % 8;

	/*
	 * sanity check!
	 */
	if (newBit != 0 && newBit != 1)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("new bit must be 0 or 1")));

	/*
	 * Make a copy of the original varlena.
	 */
	res = (bytea *) palloc(VARSIZE(v));
	memcpy((char *) res, (char *) v, VARSIZE(v));

	/*
	 * Update the byte.
	 */
	oldByte = ((unsigned char *) VARDATA(res))[byteNo];

	if (newBit == 0)
		newByte = oldByte & (~(1 << bitNo));
	else
		newByte = oldByte | (1 << bitNo);

	((unsigned char *) VARDATA(res))[byteNo] = newByte;

	PG_RETURN_BYTEA_P(res);
}


/* text_name()
 * Converts a text type to a Name type.
 */
Datum
text_name(PG_FUNCTION_ARGS)
{
	text	   *s = PG_GETARG_TEXT_P(0);
	Name		result;
	int			len;

	len = VARSIZE(s) - VARHDRSZ;

	/* Truncate oversize input */
	if (len >= NAMEDATALEN)
		len = NAMEDATALEN - 1;

#ifdef STRINGDEBUG
	printf("text- convert string length %d (%d) ->%d\n",
		   VARSIZE(s) - VARHDRSZ, VARSIZE(s), len);
#endif

	result = (Name) palloc(NAMEDATALEN);
	memcpy(NameStr(*result), VARDATA(s), len);