oracle_compat.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 1,498 行 · 第 1/3 页

		text	   *string = PG_GETARG_TEXT_PP(0);
		text	   *result;
		wchar_t    *workspace;
		int			wasalnum = 0;
		int			i;

		workspace = texttowcs(string);

		for (i = 0; workspace[i] != 0; i++)
		{
			if (wasalnum)
				workspace[i] = towlower(workspace[i]);
			else
				workspace[i] = towupper(workspace[i]);
			wasalnum = iswalnum(workspace[i]);
		}

		result = wcstotext(workspace, i);

		pfree(workspace);

		PG_RETURN_TEXT_P(result);
	}
	else
#endif   /* USE_WIDE_UPPER_LOWER */
	{
		text	   *string = PG_GETARG_TEXT_P_COPY(0);
		int			wasalnum = 0;
		char	   *ptr;
		int			m;

		/*
		 * Since we copied the string, we can scribble directly on the value
		 */
		ptr = VARDATA(string);
		m = VARSIZE(string) - VARHDRSZ;

		while (m-- > 0)
		{
			if (wasalnum)
				*ptr = tolower((unsigned char) *ptr);
			else
				*ptr = toupper((unsigned char) *ptr);
			wasalnum = isalnum((unsigned char) *ptr);
			ptr++;
		}

		PG_RETURN_TEXT_P(string);
	}
}


/********************************************************************
 *
 * lpad
 *
 * Syntax:
 *
 *	 text lpad(text string1, int4 len, text string2)
 *
 * Purpose:
 *
 *	 Returns string1, left-padded to length len with the sequence of
 *	 characters in string2.  If len is less than the length of string1,
 *	 instead truncate (on the right) to len.
 *
 ********************************************************************/

Datum
lpad(PG_FUNCTION_ARGS)
{
	text	   *string1 = PG_GETARG_TEXT_PP(0);
	int32		len = PG_GETARG_INT32(1);
	text	   *string2 = PG_GETARG_TEXT_PP(2);
	text	   *ret;
	char	   *ptr1,
			   *ptr2,
			   *ptr2start,
			   *ptr2end,
			   *ptr_ret;
	int			m,
				s1len,
				s2len;

	int			bytelen;

	/* Negative len is silently taken as zero */
	if (len < 0)
		len = 0;

	s1len = VARSIZE_ANY_EXHDR(string1);
	if (s1len < 0)
		s1len = 0;				/* shouldn't happen */

	s2len = VARSIZE_ANY_EXHDR(string2);
	if (s2len < 0)
		s2len = 0;				/* shouldn't happen */

	s1len = pg_mbstrlen_with_len(VARDATA_ANY(string1), s1len);

	if (s1len > len)
		s1len = len;			/* truncate string1 to len chars */

	if (s2len <= 0)
		len = s1len;			/* nothing to pad with, so don't pad */

	bytelen = pg_database_encoding_max_length() * len;

	/* check for integer overflow */
	if (len != 0 && bytelen / pg_database_encoding_max_length() != len)
		ereport(ERROR,
				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
				 errmsg("requested length too large")));

	ret = (text *) palloc(VARHDRSZ + bytelen);

	m = len - s1len;

	ptr2 = ptr2start = VARDATA_ANY(string2);
	ptr2end = ptr2 + s2len;
	ptr_ret = VARDATA(ret);

	while (m--)
	{
		int			mlen = pg_mblen(ptr2);

		memcpy(ptr_ret, ptr2, mlen);
		ptr_ret += mlen;
		ptr2 += mlen;
		if (ptr2 == ptr2end)	/* wrap around at end of s2 */
			ptr2 = ptr2start;
	}

	ptr1 = VARDATA_ANY(string1);

	while (s1len--)
	{
		int			mlen = pg_mblen(ptr1);

		memcpy(ptr_ret, ptr1, mlen);
		ptr_ret += mlen;
		ptr1 += mlen;
	}

	SET_VARSIZE(ret, ptr_ret - (char *) ret);

	PG_RETURN_TEXT_P(ret);
}


/********************************************************************
 *
 * rpad
 *
 * Syntax:
 *
 *	 text rpad(text string1, int4 len, text string2)
 *
 * Purpose:
 *
 *	 Returns string1, right-padded to length len with the sequence of
 *	 characters in string2.  If len is less than the length of string1,
 *	 instead truncate (on the right) to len.
 *
 ********************************************************************/

Datum
rpad(PG_FUNCTION_ARGS)
{
	text	   *string1 = PG_GETARG_TEXT_PP(0);
	int32		len = PG_GETARG_INT32(1);
	text	   *string2 = PG_GETARG_TEXT_PP(2);
	text	   *ret;
	char	   *ptr1,
			   *ptr2,
			   *ptr2start,
			   *ptr2end,
			   *ptr_ret;
	int			m,
				s1len,
				s2len;

	int			bytelen;

	/* Negative len is silently taken as zero */
	if (len < 0)
		len = 0;

	s1len = VARSIZE_ANY_EXHDR(string1);
	if (s1len < 0)
		s1len = 0;				/* shouldn't happen */

	s2len = VARSIZE_ANY_EXHDR(string2);
	if (s2len < 0)
		s2len = 0;				/* shouldn't happen */

	s1len = pg_mbstrlen_with_len(VARDATA_ANY(string1), s1len);

	if (s1len > len)
		s1len = len;			/* truncate string1 to len chars */

	if (s2len <= 0)
		len = s1len;			/* nothing to pad with, so don't pad */

	bytelen = pg_database_encoding_max_length() * len;

	/* Check for integer overflow */
	if (len != 0 && bytelen / pg_database_encoding_max_length() != len)
		ereport(ERROR,
				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
				 errmsg("requested length too large")));

	ret = (text *) palloc(VARHDRSZ + bytelen);
	m = len - s1len;

	ptr1 = VARDATA_ANY(string1);
	ptr_ret = VARDATA(ret);

	while (s1len--)
	{
		int			mlen = pg_mblen(ptr1);

		memcpy(ptr_ret, ptr1, mlen);
		ptr_ret += mlen;
		ptr1 += mlen;
	}

	ptr2 = ptr2start = VARDATA_ANY(string2);
	ptr2end = ptr2 + s2len;

	while (m--)
	{
		int			mlen = pg_mblen(ptr2);

		memcpy(ptr_ret, ptr2, mlen);
		ptr_ret += mlen;
		ptr2 += mlen;
		if (ptr2 == ptr2end)	/* wrap around at end of s2 */
			ptr2 = ptr2start;
	}

	SET_VARSIZE(ret, ptr_ret - (char *) ret);

	PG_RETURN_TEXT_P(ret);
}


/********************************************************************
 *
 * btrim
 *
 * Syntax:
 *
 *	 text btrim(text string, text set)
 *
 * Purpose:
 *
 *	 Returns string with characters removed from the front and back
 *	 up to the first character not in set.
 *
 ********************************************************************/

Datum
btrim(PG_FUNCTION_ARGS)
{
	text	   *string = PG_GETARG_TEXT_PP(0);
	text	   *set = PG_GETARG_TEXT_PP(1);
	text	   *ret;

	ret = dotrim(VARDATA_ANY(string), VARSIZE_ANY_EXHDR(string),
				 VARDATA_ANY(set), VARSIZE_ANY_EXHDR(set),
				 true, true);

	PG_RETURN_TEXT_P(ret);
}

/********************************************************************
 *
 * btrim1 --- btrim with set fixed as ' '
 *
 ********************************************************************/

Datum
btrim1(PG_FUNCTION_ARGS)
{
	text	   *string = PG_GETARG_TEXT_PP(0);
	text	   *ret;

	ret = dotrim(VARDATA_ANY(string), VARSIZE_ANY_EXHDR(string),
				 " ", 1,
				 true, true);

	PG_RETURN_TEXT_P(ret);
}

/*
 * Common implementation for btrim, ltrim, rtrim
 */
static text *
dotrim(const char *string, int stringlen,
	   const char *set, int setlen,
	   bool doltrim, bool dortrim)
{
	text	   *result;
	int			i;

	/* Nothing to do if either string or set is empty */
	if (stringlen > 0 && setlen > 0)
	{
		if (pg_database_encoding_max_length() > 1)
		{
			/*
			 * In the multibyte-encoding case, build arrays of pointers to
			 * character starts, so that we can avoid inefficient checks in
			 * the inner loops.
			 */
			const char **stringchars;
			const char **setchars;
			int		   *stringmblen;
			int		   *setmblen;
			int			stringnchars;
			int			setnchars;
			int			resultndx;
			int			resultnchars;
			const char *p;
			int			len;
			int			mblen;
			const char *str_pos;
			int			str_len;

			stringchars = (const char **) palloc(stringlen * sizeof(char *));
			stringmblen = (int *) palloc(stringlen * sizeof(int));
			stringnchars = 0;
			p = string;
			len = stringlen;
			while (len > 0)
			{
				stringchars[stringnchars] = p;
				stringmblen[stringnchars] = mblen = pg_mblen(p);
				stringnchars++;
				p += mblen;
				len -= mblen;
			}

			setchars = (const char **) palloc(setlen * sizeof(char *));
			setmblen = (int *) palloc(setlen * sizeof(int));
			setnchars = 0;
			p = set;
			len = setlen;
			while (len > 0)
			{
				setchars[setnchars] = p;
				setmblen[setnchars] = mblen = pg_mblen(p);
				setnchars++;
				p += mblen;
				len -= mblen;
			}

			resultndx = 0;		/* index in stringchars[] */
			resultnchars = stringnchars;

			if (doltrim)
			{
				while (resultnchars > 0)
				{
					str_pos = stringchars[resultndx];
					str_len = stringmblen[resultndx];
					for (i = 0; i < setnchars; i++)
					{
						if (str_len == setmblen[i] &&
							memcmp(str_pos, setchars[i], str_len) == 0)
							break;
					}
					if (i >= setnchars)
						break;	/* no match here */
					string += str_len;
					stringlen -= str_len;
					resultndx++;
					resultnchars--;
				}
			}

			if (dortrim)
			{
				while (resultnchars > 0)
				{
					str_pos = stringchars[resultndx + resultnchars - 1];
					str_len = stringmblen[resultndx + resultnchars - 1];
					for (i = 0; i < setnchars; i++)
					{
						if (str_len == setmblen[i] &&
							memcmp(str_pos, setchars[i], str_len) == 0)
							break;
					}
					if (i >= setnchars)
						break;	/* no match here */
					stringlen -= str_len;
					resultnchars--;
				}
			}

			pfree(stringchars);
			pfree(stringmblen);
			pfree(setchars);
			pfree(setmblen);
		}
		else
		{
			/*
			 * In the single-byte-encoding case, we don't need such overhead.
			 */
			if (doltrim)
			{
				while (stringlen > 0)
				{
					char		str_ch = *string;

					for (i = 0; i < setlen; i++)
					{
						if (str_ch == set[i])
							break;
					}
					if (i >= setlen)
						break;	/* no match here */
					string++;
					stringlen--;
				}
			}

			if (dortrim)
			{
				while (stringlen > 0)
				{
					char		str_ch = string[stringlen - 1];

					for (i = 0; i < setlen; i++)
					{
						if (str_ch == set[i])
							break;
					}
					if (i >= setlen)
						break;	/* no match here */
					stringlen--;
				}
			}
		}
	}

	/* Return selected portion of string */
	result = (text *) palloc(VARHDRSZ + stringlen);
	SET_VARSIZE(result, VARHDRSZ + stringlen);
	memcpy(VARDATA(result), string, stringlen);

	return result;
}

/********************************************************************
 *
 * byteatrim
 *
 * Syntax:
 *
 *	 bytea byteatrim(byta string, bytea set)
 *
 * Purpose:
 *
 *	 Returns string with characters removed from the front and back
 *	 up to the first character not in set.
 *
 * Cloned from btrim and modified as required.
 ********************************************************************/

Datum
byteatrim(PG_FUNCTION_ARGS)
{
	bytea	   *string = PG_GETARG_BYTEA_PP(0);
	bytea	   *set = PG_GETARG_BYTEA_PP(1);
	bytea	   *ret;
	char	   *ptr,
			   *end,
			   *ptr2,
			   *ptr2start,
			   *end2;
	int			m,
				stringlen,
				setlen;

	stringlen = VARSIZE_ANY_EXHDR(string);
	setlen = VARSIZE_ANY_EXHDR(set);

	if (stringlen <= 0 || setlen <= 0)
		PG_RETURN_BYTEA_P(string);

	m = stringlen;
	ptr = VARDATA_ANY(string);
	end = ptr + stringlen - 1;
	ptr2start = VARDATA_ANY(set);
	end2 = ptr2start + setlen - 1;

	while (m > 0)