Commit 1c8f5500 authored by unknown's avatar unknown
Browse files

InnoDB: Optimize rec_get_offsets(), rec_copy_prefix_to_buf() and 

other rec_ functions based on OProfile measurements on GNU/Linux x86.


innobase/include/rem0rec.h:
  Replace FALSE/TRUE ibool comp with zero/nonzero ulint comp.
  Remove rec_set_node_ptr_flag().
innobase/include/rem0rec.ic:
  Replace FALSE/TRUE ibool comp with zero/nonzero ulint comp.
  Remove rec_set_node_ptr_flag().
  Add UNIV_LIKELY and UNIV_UNLIKELY hints.
  Correct a spelling error in comment.
  Simplify rec_get_deleted_flag().
innobase/rem/rem0rec.c:
  Add UNIV_LIKELY and UNIV_UNLIKELY hints.
  rec_init_offsets(), rec_get_offsets_func(): Optimize for x86.
  rec_set_field_extern_bits(): Move "comp" flag outside the loop.
  rec_copy_prefix_to_buf(): Add UNIV_PREFETCH hints.
parent 33d5b13b

innobase/include/rem0rec.h

+13 −21
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ rec_get_next_offs( 
			/* out: the page offset of the next 

			chained record */

	rec_t*	rec,	/* in: physical record */

	ibool	comp);	/* in: TRUE=compact page format */

	ulint	comp);	/* in: nonzero=compact page format */

/**********************************************************

The following function is used to set the next record offset field

of the record. */
@@ -60,7 +60,7 @@ void 
rec_set_next_offs(

/*==============*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	next);	/* in: offset of the next record */

/**********************************************************

The following function is used to get the number of fields
@@ -90,7 +90,7 @@ rec_get_n_owned( 
/*============*/

			/* out: number of owned records */

	rec_t*	rec,	/* in: physical record */

	ibool	comp);	/* in: TRUE=compact page format */

	ulint	comp);	/* in: nonzero=compact page format */

/**********************************************************

The following function is used to set the number of owned

records. */
@@ -99,7 +99,7 @@ void 
rec_set_n_owned(

/*============*/

	rec_t*	rec,		/* in: physical record */

	ibool	comp,		/* in: TRUE=compact page format */

	ulint	comp,		/* in: nonzero=compact page format */

	ulint	n_owned);	/* in: the number of owned */

/**********************************************************

The following function is used to retrieve the info bits of
@@ -110,7 +110,7 @@ rec_get_info_bits( 
/*==============*/

			/* out: info bits */

	rec_t*	rec,	/* in: physical record */

	ibool	comp);	/* in: TRUE=compact page format */

	ulint	comp);	/* in: nonzero=compact page format */

/**********************************************************

The following function is used to set the info bits of a record. */

UNIV_INLINE
@@ -118,7 +118,7 @@ void 
rec_set_info_bits(

/*==============*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	bits);	/* in: info bits */

/**********************************************************

The following function retrieves the status bits of a new-style record. */
@@ -147,7 +147,7 @@ rec_get_info_and_status_bits( 
/*=========================*/

			/* out: info bits */

	rec_t*	rec,	/* in: physical record */

	ibool	comp);	/* in: TRUE=compact page format */

	ulint	comp);	/* in: nonzero=compact page format */

/**********************************************************

The following function is used to set the info and status

bits of a record.  (Only compact records have status bits.) */
@@ -156,7 +156,7 @@ void 
rec_set_info_and_status_bits(

/*=========================*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	bits);	/* in: info bits */



/**********************************************************
@@ -167,7 +167,7 @@ rec_get_deleted_flag( 
/*=================*/

			/* out: TRUE if delete marked */

	rec_t*	rec,	/* in: physical record */

	ibool	comp);	/* in: TRUE=compact page format */

	ulint	comp);	/* in: nonzero=compact page format */

/**********************************************************

The following function is used to set the deleted bit. */

UNIV_INLINE
@@ -175,7 +175,7 @@ void 
rec_set_deleted_flag(

/*=================*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ibool	flag);	/* in: TRUE if delete marked */

/**********************************************************

The following function tells if a new-style record is a node pointer. */
@@ -186,14 +186,6 @@ rec_get_node_ptr_flag( 
			/* out: TRUE if node pointer */

	rec_t*	rec);	/* in: physical record */

/**********************************************************

The following function is used to flag a record as a node pointer. */

UNIV_INLINE

void

rec_set_node_ptr_flag(

/*=================*/

	rec_t*	rec,	/* in: physical record */

	ibool	flag);	/* in: TRUE if the record is a node pointer */

/**********************************************************

The following function is used to get the order number

of the record in the heap of the index page. */

UNIV_INLINE
@@ -202,7 +194,7 @@ rec_get_heap_no( 
/*=============*/

			/* out: heap order number */

	rec_t*	rec,	/* in: physical record */

	ibool	comp);	/* in: TRUE=compact page format */

	ulint	comp);	/* in: nonzero=compact page format */

/**********************************************************

The following function is used to set the heap number

field in the record. */
@@ -211,7 +203,7 @@ void 
rec_set_heap_no(

/*=============*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	heap_no);/* in: the heap number */

/**********************************************************

The following function is used to test whether the data offsets
@@ -305,7 +297,7 @@ rec_get_nth_field( 
Determine if the offsets are for a record in the new

compact format. */

UNIV_INLINE

ibool

ulint

rec_offs_comp(

/*==========*/

				/* out: TRUE if compact format */

innobase/include/rem0rec.ic

+30 −50
Original line number Diff line number Diff line
@@ -265,7 +265,7 @@ rec_get_next_offs( 
			/* out: the page offset of the next chained record, or

			0 if none */

	rec_t*	rec,	/* in: physical record */

	ibool	comp)	/* in: TRUE=compact page format */

	ulint	comp)	/* in: nonzero=compact page format */

{	

	ulint	field_value;
@@ -312,7 +312,7 @@ void 
rec_set_next_offs(

/*==============*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	next)	/* in: offset of the next record, or 0 if none */

{

	ut_ad(rec);
@@ -414,7 +414,7 @@ rec_get_n_fields( 
{

	ut_ad(rec);

	ut_ad(index);

	if (!index->table->comp) {

	if (UNIV_UNLIKELY(!index->table->comp)) {

		return(rec_get_n_fields_old(rec));

	}

	switch (rec_get_status(rec)) {
@@ -440,7 +440,7 @@ rec_get_n_owned( 
/*============*/

			/* out: number of owned records */

	rec_t*	rec,	/* in: physical record */

	ibool	comp)	/* in: TRUE=compact page format */

	ulint	comp)	/* in: nonzero=compact page format */

{

	ulint	ret;
@@ -461,7 +461,7 @@ void 
rec_set_n_owned(

/*============*/

	rec_t*	rec,		/* in: physical record */

	ibool	comp,		/* in: TRUE=compact page format */

	ulint	comp,		/* in: nonzero=compact page format */

	ulint	n_owned)	/* in: the number of owned */

{

	ut_ad(rec);
@@ -480,7 +480,7 @@ rec_get_info_bits( 
/*==============*/

			/* out: info bits */

	rec_t*	rec,	/* in: physical record */

	ibool	comp)	/* in: TRUE=compact page format */

	ulint	comp)	/* in: nonzero=compact page format */

{

	ulint	ret;
@@ -501,7 +501,7 @@ void 
rec_set_info_bits(

/*==============*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	bits)	/* in: info bits */

{

	ut_ad(rec);
@@ -537,14 +537,14 @@ rec_get_info_and_status_bits( 
/*=========================*/

			/* out: info bits */

	rec_t*	rec,	/* in: physical record */

	ibool	comp)	/* in: TRUE=compact page format */

	ulint	comp)	/* in: nonzero=compact page format */

{

	ulint	bits;

#if (REC_NEW_STATUS_MASK >> REC_NEW_STATUS_SHIFT) \

& (REC_INFO_BITS_MASK >> REC_INFO_BITS_SHIFT)

# error "REC_NEW_STATUS_MASK and REC_INFO_BITS_MASK overlap"

#endif

	if (comp) {

	if (UNIV_EXPECT(comp, REC_OFFS_COMPACT)) {

		bits = rec_get_info_bits(rec, TRUE) | rec_get_status(rec);

	} else {

		bits = rec_get_info_bits(rec, FALSE);
@@ -560,7 +560,7 @@ void 
rec_set_info_and_status_bits(

/*=========================*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	bits)	/* in: info bits */

{

#if (REC_NEW_STATUS_MASK >> REC_NEW_STATUS_SHIFT) \
@@ -583,14 +583,15 @@ rec_get_deleted_flag( 
/*=================*/

			/* out: TRUE if delete marked */

	rec_t*	rec,	/* in: physical record */

	ibool	comp)	/* in: TRUE=compact page format */

	ulint	comp)	/* in: nonzero=compact page format */

{

	if (REC_INFO_DELETED_FLAG & rec_get_info_bits(rec, comp)) {



		return(TRUE);

	if (UNIV_EXPECT(comp, REC_OFFS_COMPACT)) {

		return(0 != rec_get_bit_field_1(rec, REC_NEW_INFO_BITS,

				REC_INFO_DELETED_FLAG, REC_INFO_BITS_SHIFT));

	} else {

		return(0 != rec_get_bit_field_1(rec, REC_OLD_INFO_BITS,

				REC_INFO_DELETED_FLAG, REC_INFO_BITS_SHIFT));

	}



	return(FALSE);

}



/**********************************************************
@@ -600,24 +601,23 @@ void 
rec_set_deleted_flag(

/*=================*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ibool	flag)	/* in: TRUE if delete marked */

{

	ulint	old_val;

	ulint	new_val;

	ulint	val;



	ut_ad(TRUE == 1);

	ut_ad(flag <= TRUE);



	old_val = rec_get_info_bits(rec, comp);

	val = rec_get_info_bits(rec, comp);

	

	if (flag) {

		new_val = REC_INFO_DELETED_FLAG | old_val;

		val |= REC_INFO_DELETED_FLAG;

	} else {

		new_val = ~REC_INFO_DELETED_FLAG & old_val;

		val &= ~REC_INFO_DELETED_FLAG;

	}



	rec_set_info_bits(rec, comp, new_val);

	rec_set_info_bits(rec, comp, val);

}



/**********************************************************
@@ -632,26 +632,6 @@ rec_get_node_ptr_flag( 
	return(REC_STATUS_NODE_PTR == rec_get_status(rec));

}



/**********************************************************

The following function is used to flag a record as a node pointer. */

UNIV_INLINE

void

rec_set_node_ptr_flag(

/*=================*/

	rec_t*	rec,	/* in: physical record */

	ibool	flag)	/* in: TRUE if the record is a node pointer */

{

	ulint	status;

	ut_ad(flag <= TRUE);

	ut_ad(REC_STATUS_NODE_PTR >= rec_get_status(rec));

	if (flag) {

		status = REC_STATUS_NODE_PTR;

	} else {

		status = REC_STATUS_ORDINARY;

	}

	rec_set_status(rec, status);

}



/**********************************************************

The following function is used to get the order number of the record in the

heap of the index page. */
@@ -661,7 +641,7 @@ rec_get_heap_no( 
/*=============*/

			/* out: heap order number */

	rec_t*	rec,	/* in: physical record */

	ibool	comp)	/* in: TRUE=compact page format */

	ulint	comp)	/* in: nonzero=compact page format */

{

	ulint	ret;
@@ -682,7 +662,7 @@ void 
rec_set_heap_no(

/*=============*/

	rec_t*	rec,	/* in: physical record */

	ibool	comp,	/* in: TRUE=compact page format */

	ulint	comp,	/* in: nonzero=compact page format */

	ulint	heap_no)/* in: the heap number */

{

	ut_ad(heap_no <= REC_MAX_HEAP_NO);
@@ -843,7 +823,7 @@ rec_offs_validate( 
{

	ulint	i	= rec_offs_n_fields(offsets);

	ulint	last	= ULINT_MAX;

	ibool	comp	= (*rec_offs_base(offsets) & REC_OFFS_COMPACT) != 0;

	ulint	comp	= *rec_offs_base(offsets) & REC_OFFS_COMPACT;



	if (rec) {

		ut_ad((ulint) rec == offsets[2]);
@@ -926,7 +906,7 @@ rec_get_nth_field( 
	ut_ad(n < rec_offs_n_fields(offsets));

	ut_ad(len);



	if (n == 0) {

	if (UNIV_UNLIKELY(n == 0)) {

		field = rec;

	} else {

		field = rec + (rec_offs_base(offsets)[n] & REC_OFFS_MASK);
@@ -1037,7 +1017,7 @@ rec_set_nth_field_extern_bit( 
				where rec is, or NULL; in the NULL case

				we do not write to log about the change */

{

	if (index->table->comp) {

	if (UNIV_LIKELY(index->table->comp)) {

		rec_set_nth_field_extern_bit_new(rec, index, i, val, mtr);

	} else {

		rec_set_nth_field_extern_bit_old(rec, i, val, mtr);
@@ -1452,7 +1432,7 @@ rec_get_converted_size( 
				? dict_index_get_n_unique_in_tree(index) + 1

				: dict_index_get_n_fields(index)));



	if (index->table->comp) {

	if (UNIV_LIKELY(index->table->comp)) {

		return(rec_get_converted_size_new(index, dtuple));

	}

innobase/rem/rem0rec.c

+93 −53
Original line number Diff line number Diff line
@@ -159,22 +159,20 @@ rec_init_offsets( 
	ulint*		offsets)/* in/out: array of offsets;

				in: n=rec_offs_n_fields(offsets) */

{

	ulint	n_fields = rec_offs_n_fields(offsets);

	ulint	i	= 0;

	ulint	offs;



	rec_offs_make_valid(rec, index, offsets);



	if (index->table->comp) {

	if (UNIV_LIKELY(index->table->comp)) {

		const byte*	nulls;

		const byte*	lens;

		dict_field_t*	field;

		dtype_t*	type;

		ulint		null_mask;

		ulint		status = rec_get_status(rec);

		ulint		n_node_ptr_field = ULINT_UNDEFINED;



		switch (status) {

		switch (UNIV_EXPECT(status, REC_STATUS_ORDINARY)) {

		case REC_STATUS_INFIMUM:

		case REC_STATUS_SUPREMUM:

			/* the field is 8 bytes long */
@@ -196,56 +194,74 @@ rec_init_offsets( 
		null_mask = 1;



		/* read the lengths of fields 0..n */

		for (; i < n_fields; i++) {

			ibool	is_null = FALSE, is_external = FALSE;

		do {

			ulint	len;

			if (i == n_node_ptr_field) {

				len = 4;

			if (UNIV_UNLIKELY(i == n_node_ptr_field)) {

				len = offs += 4;

				goto resolved;

			}



			field = dict_index_get_nth_field(index, i);

			type = dict_col_get_type(dict_field_get_col(field));

			if (!(dtype_get_prtype(type) & DATA_NOT_NULL)) {

			if (!(dtype_get_prtype(dict_col_get_type(

						dict_field_get_col(field)))

						& DATA_NOT_NULL)) {

				/* nullable field => read the null flag */

				is_null = (*nulls & null_mask) != 0;

				null_mask <<= 1;

				if (null_mask == 0x100) {



				if (UNIV_UNLIKELY(!(byte) null_mask)) {

					nulls--;

					null_mask = 1;

				}



				if (*nulls & null_mask) {

					null_mask <<= 1;

					/* No length is stored for NULL fields.

					We do not advance offs, and we set

					the length to zero and enable the

					SQL NULL flag in offsets[]. */

					len = REC_OFFS_SQL_NULL;

					goto resolved;

				}

				null_mask <<= 1;



			if (is_null) {

				/* No length is stored for NULL fields. */

				len = 0;

			} else if (!field->fixed_len) {

				ut_ad(!field->fixed_len);

				goto variable_length;

			}



			if (UNIV_UNLIKELY(!field->fixed_len)) {

				dtype_t*	type;

			variable_length:

				/* Variable-length field: read the length */

				type = dict_col_get_type(

						dict_field_get_col(field));

				len = *lens--;

				if (dtype_get_len(type) > 255

				    || dtype_get_mtype(type) == DATA_BLOB) {

				if (UNIV_UNLIKELY(dtype_get_len(type) > 255)

				    || UNIV_UNLIKELY(dtype_get_mtype(type)

							== DATA_BLOB)) {

					if (len & 0x80) {

						/* 1exxxxxxx xxxxxxxx */

						is_external = !!(len & 0x40);

						len &= 0x3f;

						len <<= 8;

						len |= *lens--;



						offs += len & 0x3fff;

						if (UNIV_UNLIKELY(len

								& 0x4000)) {

							len = offs

							| REC_OFFS_EXTERNAL;

						} else {

							len = offs;

						}



						goto resolved;

					}

				}



				len = offs += len;

			} else {

				len = field->fixed_len;

				len = offs += field->fixed_len;

			}

		resolved:

			offs += len;

			len = offs;

			if (is_external) {

				len |= REC_OFFS_EXTERNAL;

			}

			if (is_null) {

				len |= REC_OFFS_SQL_NULL;

			}

			rec_offs_base(offsets)[i + 1] = len;

		}

		} while (++i < rec_offs_n_fields(offsets));



		*rec_offs_base(offsets) =

			(rec - (lens + 1)) | REC_OFFS_COMPACT;
@@ -253,22 +269,22 @@ rec_init_offsets( 
		/* Old-style record: determine extra size and end offsets */

		offs = REC_N_OLD_EXTRA_BYTES;

		if (rec_get_1byte_offs_flag(rec)) {

			offs += n_fields;

			offs += rec_offs_n_fields(offsets);

			*rec_offs_base(offsets) = offs;

			/* Determine offsets to fields */

			for (; i < n_fields; i++) {

			do {

				offs = rec_1_get_field_end_info(rec, i);

				if (offs & REC_1BYTE_SQL_NULL_MASK) {

					offs &= ~REC_1BYTE_SQL_NULL_MASK;

					offs |= REC_OFFS_SQL_NULL;

				}

				rec_offs_base(offsets)[1 + i] = offs;

			}

			} while (++i < rec_offs_n_fields(offsets));

		} else {

			offs += 2 * n_fields;

			offs += 2 * rec_offs_n_fields(offsets);

			*rec_offs_base(offsets) = offs;

			/* Determine offsets to fields */

			for (; i < n_fields; i++) {

			do {

				offs = rec_2_get_field_end_info(rec, i);

				if (offs & REC_2BYTE_SQL_NULL_MASK) {

					offs &= ~REC_2BYTE_SQL_NULL_MASK;
@@ -279,7 +295,7 @@ rec_init_offsets( 
					offs |= REC_OFFS_EXTERNAL;

				}

				rec_offs_base(offsets)[1 + i] = offs;

			}

			} while (++i < rec_offs_n_fields(offsets));

		}

	}

}
@@ -310,8 +326,9 @@ rec_get_offsets_func( 
	ut_ad(index);

	ut_ad(heap);



	if (index->table->comp) {

		switch (rec_get_status(rec)) {

	if (UNIV_LIKELY(index->table->comp)) {

		switch (UNIV_EXPECT(rec_get_status(rec),

				REC_STATUS_ORDINARY)) {

		case REC_STATUS_ORDINARY:

			n = dict_index_get_n_fields(index);

			break;
@@ -331,13 +348,14 @@ rec_get_offsets_func( 
		n = rec_get_n_fields_old(rec);

	}



	if (n_fields < n) {

	if (UNIV_UNLIKELY(n_fields < n)) {

		n = n_fields;

	}



	size = n + (1 + REC_OFFS_HEADER_SIZE);



	if (!offsets || rec_offs_get_n_alloc(offsets) < size) {

	if (UNIV_UNLIKELY(!offsets) ||

			UNIV_UNLIKELY(rec_offs_get_n_alloc(offsets) < size)) {

		if (!*heap) {

			*heap = mem_heap_create_func(size * sizeof(ulint),

				NULL, MEM_HEAP_DYNAMIC, file, line);
@@ -653,8 +671,16 @@ rec_set_field_extern_bits( 
{

	ulint	i;



	if (UNIV_LIKELY(index->table->comp)) {

		for (i = 0; i < n_fields; i++) {

		rec_set_nth_field_extern_bit(rec, index, vec[i], TRUE, mtr);

			rec_set_nth_field_extern_bit_new(rec, index, vec[i],

								TRUE, mtr);

		}

	} else {

		for (i = 0; i < n_fields; i++) {

			rec_set_nth_field_extern_bit_old(rec, vec[i],

								TRUE, mtr);

		}

	}

}
@@ -949,7 +975,7 @@ rec_convert_dtuple_to_rec( 
	ut_ad(dtuple_validate(dtuple));

	ut_ad(dtuple_check_typed(dtuple));



	if (index->table->comp) {

	if (UNIV_LIKELY(index->table->comp)) {

		rec = rec_convert_dtuple_to_rec_new(buf, index, dtuple);

	} else {

		rec = rec_convert_dtuple_to_rec_old(buf, dtuple);
@@ -1078,17 +1104,19 @@ rec_copy_prefix_to_buf( 
					for the copied prefix, or NULL */

	ulint*		buf_size)	/* in/out: buffer size */

{

	byte*		nulls	= rec - (REC_N_NEW_EXTRA_BYTES + 1);

	byte*		lens	= nulls - (index->n_nullable + 7) / 8;

	byte*		nulls;

	byte*		lens;

	dict_field_t*	field;

	dtype_t*	type;

	ulint		i;

	ulint		prefix_len	= 0;

	ulint		prefix_len;

	ibool		is_null;

	ulint		null_mask	= 1;

	ulint		null_mask;

	ulint		status;



	if (!index->table->comp) {

	UNIV_PREFETCH_RW(*buf);



	if (UNIV_UNLIKELY(!index->table->comp)) {

		ut_ad(rec_validate_old(rec));

		return(rec_copy_prefix_to_buf_old(rec, n_fields,

			rec_get_field_start_offs(rec, n_fields),
@@ -1109,10 +1137,16 @@ rec_copy_prefix_to_buf( 
	case REC_STATUS_SUPREMUM:

		/* infimum or supremum record: no sense to copy anything */

	default:

		ut_a(0);

		ut_error;

		return(NULL);

	}



	nulls = rec - (REC_N_NEW_EXTRA_BYTES + 1);

	lens = nulls - (index->n_nullable + 7) / 8;

	UNIV_PREFETCH_R(lens);

	prefix_len = 0;

	null_mask = 1;



	/* read the lengths of fields 0..n */

	for (i = 0; i < n_fields; i++) {

		field = dict_index_get_nth_field(index, i);
@@ -1122,8 +1156,11 @@ rec_copy_prefix_to_buf( 
			/* nullable field => read the null flag */

			is_null = !!(*nulls & null_mask);

			null_mask <<= 1;

			if (null_mask == 0x100)

				nulls--, null_mask = 1;

			if (null_mask == 0x100) {

				--nulls;

				UNIV_PREFETCH_R(nulls);

				null_mask = 1;

			}

		}



		if (is_null) {
@@ -1138,12 +1175,15 @@ rec_copy_prefix_to_buf( 
					len &= 0x3f;

					len <<= 8;

					len |= *lens--;

					UNIV_PREFETCH_R(lens);

				}

			}

			prefix_len += len;

		}

	}



	UNIV_PREFETCH_R(rec + prefix_len);



	prefix_len += rec - (lens + 1);



	if ((*buf == NULL) || (*buf_size < prefix_len)) {