arrayfuncs.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 2,484 行 · 第 1/5 页

	bitmask = 1;

	for (i = 0; i < nitems; i++)
	{
		bool		needquote;

		/* Get source element, checking for NULL */
		if (bitmap && (*bitmap & bitmask) == 0)
		{
			values[i] = pstrdup("NULL");
			overall_length += 4;
			needquote = false;
		}
		else
		{
			Datum		itemvalue;

			itemvalue = fetch_att(p, typbyval, typlen);
			values[i] = OutputFunctionCall(&my_extra->proc, itemvalue);
			p = att_addlength_pointer(p, typlen, p);
			p = (char *) att_align_nominal(p, typalign);

			/* count data plus backslashes; detect chars needing quotes */
			if (values[i][0] == '\0')
				needquote = true;		/* force quotes for empty string */
			else if (pg_strcasecmp(values[i], "NULL") == 0)
				needquote = true;		/* force quotes for literal NULL */
			else
				needquote = false;

			for (tmp = values[i]; *tmp != '\0'; tmp++)
			{
				char		ch = *tmp;

				overall_length += 1;
				if (ch == '"' || ch == '\\')
				{
					needquote = true;
#ifndef TCL_ARRAYS
					overall_length += 1;
#endif
				}
				else if (ch == '{' || ch == '}' || ch == typdelim ||
						 isspace((unsigned char) ch))
					needquote = true;
			}
		}

		needquotes[i] = needquote;

		/* Count the pair of double quotes, if needed */
		if (needquote)
			overall_length += 2;
		/* and the comma */
		overall_length += 1;

		/* advance bitmap pointer if any */
		if (bitmap)
		{
			bitmask <<= 1;
			if (bitmask == 0x100)
			{
				bitmap++;
				bitmask = 1;
			}
		}
	}

	/*
	 * count total number of curly braces in output string
	 */
	for (i = j = 0, k = 1; i < ndim; i++)
		k *= dims[i], j += k;

	dims_str[0] = '\0';

	/* add explicit dimensions if required */
	if (needdims)
	{
		char	   *ptr = dims_str;

		for (i = 0; i < ndim; i++)
		{
			sprintf(ptr, "[%d:%d]", lb[i], lb[i] + dims[i] - 1);
			ptr += strlen(ptr);
		}
		*ptr++ = *ASSGN;
		*ptr = '\0';
	}

	retval = (char *) palloc(strlen(dims_str) + overall_length + 2 * j);
	p = retval;

#define APPENDSTR(str)	(strcpy(p, (str)), p += strlen(p))
#define APPENDCHAR(ch)	(*p++ = (ch), *p = '\0')

	if (needdims)
		APPENDSTR(dims_str);
	APPENDCHAR('{');
	for (i = 0; i < ndim; i++)
		indx[i] = 0;
	j = 0;
	k = 0;
	do
	{
		for (i = j; i < ndim - 1; i++)
			APPENDCHAR('{');

		if (needquotes[k])
		{
			APPENDCHAR('"');
#ifndef TCL_ARRAYS
			for (tmp = values[k]; *tmp; tmp++)
			{
				char		ch = *tmp;

				if (ch == '"' || ch == '\\')
					*p++ = '\\';
				*p++ = ch;
			}
			*p = '\0';
#else
			APPENDSTR(values[k]);
#endif
			APPENDCHAR('"');
		}
		else
			APPENDSTR(values[k]);
		pfree(values[k++]);

		for (i = ndim - 1; i >= 0; i--)
		{
			indx[i] = (indx[i] + 1) % dims[i];
			if (indx[i])
			{
				APPENDCHAR(typdelim);
				break;
			}
			else
				APPENDCHAR('}');
		}
		j = i;
	} while (j != -1);

#undef APPENDSTR
#undef APPENDCHAR

	pfree(values);
	pfree(needquotes);

	PG_RETURN_CSTRING(retval);
}

/*
 * array_recv :
 *		  converts an array from the external binary format to
 *		  its internal format.
 *
 * return value :
 *		  the internal representation of the input array
 */
Datum
array_recv(PG_FUNCTION_ARGS)
{
	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);
	Oid			spec_element_type = PG_GETARG_OID(1);	/* type of an array
														 * element */
	int32		typmod = PG_GETARG_INT32(2);	/* typmod for array elements */
	Oid			element_type;
	int			typlen;
	bool		typbyval;
	char		typalign;
	Oid			typioparam;
	int			i,
				nitems;
	Datum	   *dataPtr;
	bool	   *nullsPtr;
	bool		hasnulls;
	int32		nbytes;
	int32		dataoffset;
	ArrayType  *retval;
	int			ndim,
				flags,
				dim[MAXDIM],
				lBound[MAXDIM];
	ArrayMetaState *my_extra;

	/* Get the array header information */
	ndim = pq_getmsgint(buf, 4);
	if (ndim < 0)				/* we do allow zero-dimension arrays */
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
				 errmsg("invalid number of dimensions: %d", ndim)));
	if (ndim > MAXDIM)
		ereport(ERROR,
				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
				 errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
						ndim, MAXDIM)));

	flags = pq_getmsgint(buf, 4);
	if (flags != 0 && flags != 1)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
				 errmsg("invalid array flags")));

	element_type = pq_getmsgint(buf, sizeof(Oid));
	if (element_type != spec_element_type)
	{
		/* XXX Can we allow taking the input element type in any cases? */
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
				 errmsg("wrong element type")));
	}

	for (i = 0; i < ndim; i++)
	{
		dim[i] = pq_getmsgint(buf, 4);
		lBound[i] = pq_getmsgint(buf, 4);
	}

	/* This checks for overflow of array dimensions */
	nitems = ArrayGetNItems(ndim, dim);

	/*
	 * We arrange to look up info about element type, including its receive
	 * 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 = ~element_type;
	}

	if (my_extra->element_type != element_type)
	{
		/* Get info about element type, including its receive proc */
		get_type_io_data(element_type, IOFunc_receive,
						 &my_extra->typlen, &my_extra->typbyval,
						 &my_extra->typalign, &my_extra->typdelim,
						 &my_extra->typioparam, &my_extra->typiofunc);
		if (!OidIsValid(my_extra->typiofunc))
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_FUNCTION),
					 errmsg("no binary input function available for type %s",
							format_type_be(element_type))));
		fmgr_info_cxt(my_extra->typiofunc, &my_extra->proc,
					  fcinfo->flinfo->fn_mcxt);
		my_extra->element_type = element_type;
	}

	if (nitems == 0)
	{
		/* Return empty array ... but not till we've validated element_type */
		PG_RETURN_ARRAYTYPE_P(construct_empty_array(element_type));
	}

	typlen = my_extra->typlen;
	typbyval = my_extra->typbyval;
	typalign = my_extra->typalign;
	typioparam = my_extra->typioparam;

	dataPtr = (Datum *) palloc(nitems * sizeof(Datum));
	nullsPtr = (bool *) palloc(nitems * sizeof(bool));
	ReadArrayBinary(buf, nitems,
					&my_extra->proc, typioparam, typmod,
					typlen, typbyval, typalign,
					dataPtr, nullsPtr,
					&hasnulls, &nbytes);
	if (hasnulls)
	{
		dataoffset = ARR_OVERHEAD_WITHNULLS(ndim, nitems);
		nbytes += dataoffset;
	}
	else
	{
		dataoffset = 0;			/* marker for no null bitmap */
		nbytes += ARR_OVERHEAD_NONULLS(ndim);
	}
	retval = (ArrayType *) palloc(nbytes);
	SET_VARSIZE(retval, nbytes);
	retval->ndim = ndim;
	retval->dataoffset = dataoffset;
	retval->elemtype = element_type;
	memcpy(ARR_DIMS(retval), dim, ndim * sizeof(int));
	memcpy(ARR_LBOUND(retval), lBound, ndim * sizeof(int));

	CopyArrayEls(retval,
				 dataPtr, nullsPtr, nitems,
				 typlen, typbyval, typalign,
				 true);

	pfree(dataPtr);
	pfree(nullsPtr);

	PG_RETURN_ARRAYTYPE_P(retval);
}

/*
 * ReadArrayBinary:
 *	 collect the data elements of an array being read in binary style.
 *
 * Inputs:
 *	buf: the data buffer to read from.
 *	nitems: total number of array elements (already read).
 *	receiveproc: type-specific receive procedure for element datatype.
 *	typioparam, typmod: auxiliary values to pass to receiveproc.
 *	typlen, typbyval, typalign: storage parameters of element datatype.
 *
 * Outputs:
 *	values[]: filled with converted data values.
 *	nulls[]: filled with is-null markers.
 *	*hasnulls: set TRUE iff there are any null elements.
 *	*nbytes: set to total size of data area needed (including alignment
 *		padding but not including array header overhead).
 *
 * Note that values[] and nulls[] are allocated by the caller, and must have
 * nitems elements.
 */
static void
ReadArrayBinary(StringInfo buf,
				int nitems,
				FmgrInfo *receiveproc,
				Oid typioparam,
				int32 typmod,
				int typlen,
				bool typbyval,
				char typalign,
				Datum *values,
				bool *nulls,
				bool *hasnulls,
				int32 *nbytes)
{
	int			i;
	bool		hasnull;
	int32		totbytes;

	for (i = 0; i < nitems; i++)
	{
		int			itemlen;
		StringInfoData elem_buf;
		char		csave;

		/* Get and check the item length */
		itemlen = pq_getmsgint(buf, 4);
		if (itemlen < -1 || itemlen > (buf->len - buf->cursor))
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
					 errmsg("insufficient data left in message")));

		if (itemlen == -1)
		{
			/* -1 length means NULL */
			values[i] = ReceiveFunctionCall(receiveproc, NULL,
											typioparam, typmod);
			nulls[i] = true;
			continue;
		}

		/*
		 * Rather than copying data around, we just set up a phony StringInfo
		 * pointing to the correct portion of the input buffer. We assume we
		 * can scribble on the input buffer so as to maintain the convention
		 * that StringInfos have a trailing null.
		 */
		elem_buf.data = &buf->data[buf->cursor];
		elem_buf.maxlen = itemlen + 1;
		elem_buf.len = itemlen;
		elem_buf.cursor = 0;

		buf->cursor += itemlen;

		csave = buf->data[buf->cursor];
		buf->data[buf->cursor] = '\0';

		/* Now call the element's receiveproc */
		values[i] = ReceiveFunctionCall(receiveproc, &elem_buf,
										typioparam, typmod);
		nulls[i] = false;

		/* Trouble if it didn't eat the whole buffer */
		if (elem_buf.cursor != itemlen)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
					 errmsg("improper binary format in array element %d",
							i + 1)));

		buf->data[buf->cursor] = csave;
	}

	/*
	 * Check for nulls, compute total data space needed
	 */
	hasnull = false;
	totbytes = 0;
	for (i = 0; i < nitems; i++)
	{
		if (nulls[i])
			hasnull = true;
		else
		{
			/* let's just make sure data is not toasted */
			if (typlen == -1)
				values[i] = PointerGetDatum(PG_DETOAST_DATUM(values[i]));
			totbytes = att_addlength_datum(totbytes, typlen, values[i]);
			totbytes = att_align_nominal(totbytes, typalign);
			/* check for overflow of total request */
			if (!AllocSizeIsValid(totbytes))
				ereport(ERROR,
						(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
						 errmsg("array size exceeds the maximum allowed (%d)",
								(int) MaxAllocSize)));
		}
	}
	*hasnulls = hasnull;
	*nbytes = totbytes;
}


/*
 * array_send :
 *		  takes the internal representation of an array and returns a bytea
 *		  containing the array in its external binary format.
 */
Datum
array_send(PG_FUNCTION_ARGS)
{
	ArrayType  *v = PG_GETARG_ARRAYTYPE_P(0);
	Oid			element_type = ARR_ELEMTYPE(v);
	int			typlen;
	bool		typbyval;
	char		typalign;
	char	   *p;
	bits8	   *bitmap;
	int			bitmask;
	int			nitems,
				i;
	int			ndim,
			   *dim;
	StringInfoData buf;
	ArrayMetaState *my_extra;

	/*
	 * We arrange to look up info about element type, including its send
	 * 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 = ~element_type;
	}

	if (my_extra->element_type != element_type)
	{
		/* Get info about element type, including its send proc */
		get_type_io_data(element_type, IOFunc_send,
						 &my_extra->typlen, &my_extra->typbyval,
						 &my_extra->typalign, &my_extra->typdelim,
						 &my_extra->typioparam, &my_extra->typiofunc);
		if (!OidIsValid(my_extra->typiofunc))
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_FUNCTION),
					 errmsg("no binary output function available for type %s",
							format_type_be(element_type))));
		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;

	ndim = ARR_NDIM(v);
	dim = ARR_DIMS(v);
	nitems = ArrayGetNItems(ndim, dim);

	pq_begintypsend(&buf);

	/* Send the array header information */
	pq_sendint(&buf, ndim, 4);
	pq_sendint(&buf, ARR_HASNULL(v) ? 1 : 0, 4);
	pq_sendint(&buf, element_type, sizeof(Oid));
	for (i = 0; i < ndim; i++)
	{
		pq_sendint(&buf, ARR_DIMS(v)[i], 4);
		pq_sendint(&buf, ARR_LBOUND(v)[i], 4);
	}

	/* Send the array elements using the element's own sendproc */
	p = ARR_DATA_PTR(v);