arrayfuncs.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	nitems = ArrayGetNItems(ndim, dims);

	if (nitems == 0)
	{
		retval = pstrdup("{}");
		PG_RETURN_CSTRING(retval);
	}

	/*
	 * we will need to add explicit dimensions if any dimension has a lower
	 * bound other than one
	 */
	for (i = 0; i < ndim; i++)
	{
		if (lb[i] != 1)
		{
			needdims = true;
			break;
		}
	}

	/*
	 * Convert all values to string form, count total space needed (including
	 * any overhead such as escaping backslashes), and detect whether each
	 * item needs double quotes.
	 */
	values = (char **) palloc(nitems * sizeof(char *));
	needquotes = (bool *) palloc(nitems * sizeof(bool));
	p = ARR_DATA_PTR(v);
	overall_length = 1;			/* don't forget to count \0 at end. */

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

		itemvalue = fetch_att(p, typbyval, typlen);
		values[i] = DatumGetCString(FunctionCall1(&my_extra->proc,
												  itemvalue));
		p = att_addlength(p, typlen, PointerGetDatum(p));
		p = (char *) att_align(p, typalign);

		/* count data plus backslashes; detect chars needing quotes */
		if (values[i][0] == '\0')
			needquote = true;	/* force quotes for empty string */
		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;
	}

	/*
	 * 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;
	int32		nbytes;
	Datum	   *dataPtr;
	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)
		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);
	}
	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 */
		retval = (ArrayType *) palloc0(sizeof(ArrayType));
		retval->size = sizeof(ArrayType);
		retval->elemtype = element_type;
		PG_RETURN_ARRAYTYPE_P(retval);
	}

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

	dataPtr = ReadArrayBinary(buf, nitems, &my_extra->proc,
							  typioparam, typmod,
							  typlen, typbyval, typalign,
							  &nbytes);
	nbytes += ARR_OVERHEAD(ndim);

	retval = (ArrayType *) palloc0(nbytes);
	retval->size = nbytes;
	retval->ndim = ndim;
	retval->elemtype = element_type;
	memcpy(ARR_DIMS(retval), dim, ndim * sizeof(int));
	memcpy(ARR_LBOUND(retval), lBound, ndim * sizeof(int));

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

	PG_RETURN_ARRAYTYPE_P(retval);
}

/*---------------------------------------------------------------------------
 * ReadArrayBinary:
 *	 collect the data elements of an array being read in binary style.
 * result :
 *	 returns a palloc'd array of Datum representations of the array elements.
 *	 If element type is pass-by-ref, the Datums point to palloc'd values.
 *	 *nbytes is set to the amount of data space needed for the array,
 *	 including alignment padding but not including array header overhead.
 *---------------------------------------------------------------------------
 */
static Datum *
ReadArrayBinary(StringInfo buf,
				int nitems,
				FmgrInfo *receiveproc,
				Oid typioparam,
				int32 typmod,
				int typlen,
				bool typbyval,
				char typalign,
				int *nbytes)
{
	Datum	   *values;
	int			i;

	values = (Datum *) palloc(nitems * sizeof(Datum));

	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 < 0 || itemlen > (buf->len - buf->cursor))
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
					 errmsg("insufficient data left in message")));

		/*
		 * 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] = FunctionCall3(receiveproc,
								  PointerGetDatum(&elem_buf),
								  ObjectIdGetDatum(typioparam),
								  Int32GetDatum(typmod));

		/* 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;
	}

	/*
	 * Compute total data space needed
	 */
	if (typlen > 0)
		*nbytes = nitems * att_align(typlen, typalign);
	else
	{
		Assert(!typbyval);
		*nbytes = 0;
		for (i = 0; i < nitems; i++)
		{
			/* let's just make sure data is not toasted */
			if (typlen == -1)
				values[i] = PointerGetDatum(PG_DETOAST_DATUM(values[i]));
			*nbytes = att_addlength(*nbytes, typlen, values[i]);
			*nbytes = att_align(*nbytes, typalign);
		}
	}

	return values;
}


/*-------------------------------------------------------------------------
 * 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;
	int			typlen;
	bool		typbyval;
	char		typalign;
	char	   *p;
	int			nitems,
				i;
	int			ndim,
			   *dim;
	StringInfoData buf;
	ArrayMetaState *my_extra;

	/* Get information about the element type and the array dimensions */
	element_type = ARR_ELEMTYPE(v);

	/*
	 * 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 = InvalidOid;
	}

	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, v->flags, 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);
	for (i = 0; i < nitems; i++)
	{
		Datum		itemvalue;
		bytea	   *outputbytes;

		itemvalue = fetch_att(p, typbyval, typlen);

		outputbytes = DatumGetByteaP(FunctionCall1(&my_extra->proc,
												   itemvalue));
		/* We assume the result will not have been toasted */
		pq_sendint(&buf, VARSIZE(outputbytes) - VARHDRSZ, 4);
		pq_sendbytes(&buf, VARDATA(outputbytes),