varlena.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,310 行 · 第 1/4 页

		if (*nextp == separator)
		{
			nextp++;
			while (isspace((unsigned char) *nextp))
				nextp++;		/* skip leading whitespace for next */
			/* we expect another name, so done remains false */
		}
		else if (*nextp == '\0')
			done = true;
		else
			return false;		/* invalid syntax */

		/* Now safe to overwrite separator with a null */
		*endp = '\0';

		/* Truncate name if it's overlength */
		truncate_identifier(curname, strlen(curname), false);

		/*
		 * Finished isolating current name --- add it to list
		 */
		*namelist = lappend(*namelist, curname);

		/* Loop back if we didn't reach end of string */
	} while (!done);

	return true;
}


/*****************************************************************************
 *	Comparison Functions used for bytea
 *
 * Note: btree indexes need these routines not to leak memory; therefore,
 * be careful to free working copies of toasted datums.  Most places don't
 * need to be so careful.
 *****************************************************************************/

Datum
byteaeq(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	bool		result;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	/* fast path for different-length inputs */
	if (len1 != len2)
		result = false;
	else
		result = (memcmp(VARDATA(arg1), VARDATA(arg2), len1) == 0);

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

	PG_RETURN_BOOL(result);
}

Datum
byteane(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	bool		result;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	/* fast path for different-length inputs */
	if (len1 != len2)
		result = true;
	else
		result = (memcmp(VARDATA(arg1), VARDATA(arg2), len1) != 0);

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

	PG_RETURN_BOOL(result);
}

Datum
bytealt(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	int			cmp;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	cmp = memcmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));

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

	PG_RETURN_BOOL((cmp < 0) || ((cmp == 0) && (len1 < len2)));
}

Datum
byteale(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	int			cmp;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	cmp = memcmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));

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

	PG_RETURN_BOOL((cmp < 0) || ((cmp == 0) && (len1 <= len2)));
}

Datum
byteagt(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	int			cmp;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	cmp = memcmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));

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

	PG_RETURN_BOOL((cmp > 0) || ((cmp == 0) && (len1 > len2)));
}

Datum
byteage(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	int			cmp;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	cmp = memcmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));

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

	PG_RETURN_BOOL((cmp > 0) || ((cmp == 0) && (len1 >= len2)));
}

Datum
byteacmp(PG_FUNCTION_ARGS)
{
	bytea	   *arg1 = PG_GETARG_BYTEA_P(0);
	bytea	   *arg2 = PG_GETARG_BYTEA_P(1);
	int			len1,
				len2;
	int			cmp;

	len1 = VARSIZE(arg1) - VARHDRSZ;
	len2 = VARSIZE(arg2) - VARHDRSZ;

	cmp = memcmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if ((cmp == 0) && (len1 != len2))
		cmp = (len1 < len2) ? -1 : 1;

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

	PG_RETURN_INT32(cmp);
}

/*
 * replace_text
 * replace all occurrences of 'old_sub_str' in 'orig_str'
 * with 'new_sub_str' to form 'new_str'
 *
 * returns 'orig_str' if 'old_sub_str' == '' or 'orig_str' == ''
 * otherwise returns 'new_str'
 */
Datum
replace_text(PG_FUNCTION_ARGS)
{
	text	   *left_text;
	text	   *right_text;
	text	   *buf_text;
	text	   *ret_text;
	int			curr_posn;
	text	   *src_text = PG_GETARG_TEXT_P(0);
	int			src_text_len = TEXTLEN(src_text);
	text	   *from_sub_text = PG_GETARG_TEXT_P(1);
	int			from_sub_text_len = TEXTLEN(from_sub_text);
	text	   *to_sub_text = PG_GETARG_TEXT_P(2);
	char	   *to_sub_str = PG_TEXT_GET_STR(to_sub_text);
	StringInfo	str = makeStringInfo();

	if (src_text_len == 0 || from_sub_text_len == 0)
		PG_RETURN_TEXT_P(src_text);

	buf_text = TEXTDUP(src_text);
	curr_posn = TEXTPOS(buf_text, from_sub_text);

	while (curr_posn > 0)
	{
		left_text = LEFT(buf_text, from_sub_text);
		right_text = RIGHT(buf_text, from_sub_text, from_sub_text_len);

		appendStringInfoString(str, PG_TEXT_GET_STR(left_text));
		appendStringInfoString(str, to_sub_str);

		pfree(buf_text);
		pfree(left_text);
		buf_text = right_text;
		curr_posn = TEXTPOS(buf_text, from_sub_text);
	}

	appendStringInfoString(str, PG_TEXT_GET_STR(buf_text));
	pfree(buf_text);

	ret_text = PG_STR_GET_TEXT(str->data);
	pfree(str->data);
	pfree(str);

	PG_RETURN_TEXT_P(ret_text);
}

/*
 * split_text
 * parse input string
 * return ord item (1 based)
 * based on provided field separator
 */
Datum
split_text(PG_FUNCTION_ARGS)
{
	text	   *inputstring = PG_GETARG_TEXT_P(0);
	int			inputstring_len = TEXTLEN(inputstring);
	text	   *fldsep = PG_GETARG_TEXT_P(1);
	int			fldsep_len = TEXTLEN(fldsep);
	int			fldnum = PG_GETARG_INT32(2);
	int			start_posn = 0;
	int			end_posn = 0;
	text	   *result_text;

	/* return empty string for empty input string */
	if (inputstring_len < 1)
		PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));

	/* empty field separator */
	if (fldsep_len < 1)
	{
		if (fldnum == 1)		/* first field - just return the input
								 * string */
			PG_RETURN_TEXT_P(inputstring);
		else
/* otherwise return an empty string */
			PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
	}

	/* field number is 1 based */
	if (fldnum < 1)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("field position must be greater than zero")));

	start_posn = text_position(PointerGetDatum(inputstring),
							   PointerGetDatum(fldsep),
							   fldnum - 1);
	end_posn = text_position(PointerGetDatum(inputstring),
							 PointerGetDatum(fldsep),
							 fldnum);

	if ((start_posn == 0) && (end_posn == 0))	/* fldsep not found */
	{
		if (fldnum == 1)		/* first field - just return the input
								 * string */
			PG_RETURN_TEXT_P(inputstring);
		else
/* otherwise return an empty string */
			PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
	}
	else if ((start_posn != 0) && (end_posn == 0))
	{
		/* last field requested */
		result_text = text_substring(PointerGetDatum(inputstring), start_posn + fldsep_len, -1, true);
		PG_RETURN_TEXT_P(result_text);
	}
	else if ((start_posn == 0) && (end_posn != 0))
	{
		/* first field requested */
		result_text = LEFT(inputstring, fldsep);
		PG_RETURN_TEXT_P(result_text);
	}
	else
	{
		/* prior to last field requested */
		result_text = text_substring(PointerGetDatum(inputstring), start_posn + fldsep_len, end_posn - start_posn - fldsep_len, false);
		PG_RETURN_TEXT_P(result_text);
	}
}

/*
 * text_to_array
 * parse input string
 * return text array of elements
 * based on provided field separator
 */
Datum
text_to_array(PG_FUNCTION_ARGS)
{
	text	   *inputstring = PG_GETARG_TEXT_P(0);
	int			inputstring_len = TEXTLEN(inputstring);
	text	   *fldsep = PG_GETARG_TEXT_P(1);
	int			fldsep_len = TEXTLEN(fldsep);
	int			fldnum;
	int			start_posn = 0;
	int			end_posn = 0;
	text	   *result_text = NULL;
	ArrayBuildState *astate = NULL;
	MemoryContext oldcontext = CurrentMemoryContext;

	/* return NULL for empty input string */
	if (inputstring_len < 1)
		PG_RETURN_NULL();

	/*
	 * empty field separator return one element, 1D, array using the input
	 * string
	 */
	if (fldsep_len < 1)
		PG_RETURN_ARRAYTYPE_P(create_singleton_array(fcinfo, TEXTOID,
									   CStringGetDatum(inputstring), 1));

	/* start with end position holding the initial start position */
	end_posn = 0;
	for (fldnum = 1;; fldnum++) /* field number is 1 based */
	{
		Datum		dvalue;
		bool		disnull = false;

		start_posn = end_posn;
		end_posn = text_position(PointerGetDatum(inputstring),
								 PointerGetDatum(fldsep),
								 fldnum);

		if ((start_posn == 0) && (end_posn == 0))		/* fldsep not found */
		{
			if (fldnum == 1)
			{
				/*
				 * first element return one element, 1D, array using the
				 * input string
				 */
				PG_RETURN_ARRAYTYPE_P(create_singleton_array(fcinfo, TEXTOID,
									   CStringGetDatum(inputstring), 1));
			}
			else
			{
				/* otherwise create array and exit */
				PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, oldcontext));
			}
		}
		else if ((start_posn != 0) && (end_posn == 0))
		{
			/* last field requested */
			result_text = text_substring(PointerGetDatum(inputstring), start_posn + fldsep_len, -1, true);
		}
		else if ((start_posn == 0) && (end_posn != 0))
		{
			/* first field requested */
			result_text = LEFT(inputstring, fldsep);
		}
		else
		{
			/* prior to last field requested */
			result_text = text_substring(PointerGetDatum(inputstring), start_posn + fldsep_len, end_posn - start_posn - fldsep_len, false);
		}

		/* stash away current value */
		dvalue = PointerGetDatum(result_text);
		astate = accumArrayResult(astate, dvalue,
								  disnull, TEXTOID, oldcontext);

	}

	/* never reached -- keep compiler quiet */
	PG_RETURN_NULL();
}

/*
 * array_to_text
 * concatenate Cstring representation of input array elements
 * using provided field separator
 */
Datum
array_to_text(PG_FUNCTION_ARGS)
{
	ArrayType  *v = PG_GETARG_ARRAYTYPE_P(0);
	char	   *fldsep = PG_TEXTARG_GET_STR(1);
	int			nitems,
			   *dims,
				ndims;
	char	   *p;
	Oid			element_type;
	int			typlen;
	bool		typbyval;
	char		typalign;
	Oid			typelem;
	StringInfo	result_str = makeStringInfo();
	int			i;
	ArrayMetaState *my_extra;

	p = ARR_DATA_PTR(v);
	ndims = ARR_NDIM(v);
	dims = ARR_DIMS(v);
	nitems = ArrayGetNItems(ndims, dims);

	/* if there are no elements, return an empty string */
	if (nitems == 0)
		PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));

	element_type = ARR_ELEMTYPE(v);

	/*
	 * We arrange to look up info about element type, including its output
	 * conversion proc, only once per series of calls, assuming the
	 * element type doesn't change underneath us.
	 */
	my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
	if (my_extra == NULL)
	{
		fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
												 sizeof(ArrayMetaState));
		my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
		my_extra->element_type = InvalidOid;
	}

	if (my_extra->element_type != element_type)
	{
		/*
		 * Get info about element type, including its output conversion
		 * proc
		 */
		get_type_io_data(element_type, IOFunc_output,
						 &my_extra->typlen, &my_extra->typbyval,
						 &my_extra->typalign, &my_extra->typdelim,
						 &my_extra->typelem, &my_extra->typiofunc);
		fmgr_info_cxt(my_extra->typiofunc, &my_extra->proc,
					  fcinfo->flinfo->fn_mcxt);
		my_extra->element_type = element_type;
	}
	typlen = my_extra->typlen;
	typbyval = my_extra->typbyval;
	typalign = my_extra->typalign;
	typelem = my_extra->typelem;

	for (i = 0; i < nitems; i++)
	{
		Datum		itemvalue;
		char	   *value;

		itemvalue = fetch_att(p, typbyval, typlen);

		value = DatumGetCString(FunctionCall3(&my_extra->proc,
											  itemvalue,
											  ObjectIdGetDatum(typelem),
											  Int32GetDatum(-1)));

		if (i > 0)
			appendStringInfo(result_str, "%s%s", fldsep, value);
		else
			appendStringInfo(result_str, "%s", value);

		p = att_addlength(p, typlen, PointerGetDatum(p));
		p = (char *) att_align(p, typalign);
	}

	PG_RETURN_TEXT_P(PG_STR_GET_TEXT(result_str->data));
}

#define HEXBASE 16
/*
 * Convert a int32 to a string containing a base 16 (hex) representation of
 * the number.
 */
Datum
to_hex32(PG_FUNCTION_ARGS)
{
	uint32		value = (uint32) PG_GETARG_INT32(0);
	text	   *result_text;
	char	   *ptr;
	const char *digits = "0123456789abcdef";
	char		buf[32];		/* bigger than needed, but reasonable */

	ptr = buf + sizeof(buf) - 1;
	*ptr = '\0';

	do
	{
		*--ptr = digits[value % HEXBASE];
		value /= HEXBASE;
	} while (ptr > buf && value);

	result_text = PG_STR_GET_TEXT(ptr);
	PG_RETURN_TEXT_P(result_text);
}

/*
 * Convert a int64 to a string containing a base 16 (hex) representation of
 * the number.
 */
Datum
to_hex64(PG_FUNCTION_ARGS)
{
	uint64		value = (uint64) PG_GETARG_INT64(0);
	text	   *result_text;
	char	   *ptr;
	const char *digits = "0123456789abcdef";
	char		buf[32];		/* bigger than needed, but reasonable */

	ptr = buf + sizeof(buf) - 1;
	*ptr = '\0';

	do
	{
		*--ptr = digits[value % HEXBASE];
		value /= HEXBASE;
	} while (ptr > buf && value);

	result_text = PG_STR_GET_TEXT(ptr);
	PG_RETURN_TEXT_P(result_text);
}

/*
 * Create an md5 hash of a text string and return it as hex
 *
 * md5 produces a 16 byte (128 bit) hash; double it for hex
 */
#define MD5_HASH_LEN  32

Datum
md5_text(PG_FUNCTION_ARGS)
{
	char	   *buff = PG_TEXT_GET_STR(PG_GETARG_TEXT_P(0));
	size_t		len = strlen(buff);
	char	   *hexsum;
	text	   *result_text;

	/* leave room for the terminating '\0' */
	hexsum = (char *) palloc(MD5_HASH_LEN + 1);

	/* get the hash result */
	md5_hash((void *) buff, len, hexsum);

	/* convert to text and return it */
	result_text = PG_STR_GET_TEXT(hexsum);
	PG_RETURN_TEXT_P(result_text);
}