88 lines
3.1 KiB
Plaintext
88 lines
3.1 KiB
Plaintext
/*****************************************************************************
|
|
|
|
Copyright (c) 2006, 2018, Oracle and/or its affiliates. All Rights Reserved.
|
|
|
|
This program is free software; you can redistribute it and/or modify it under
|
|
the terms of the GNU General Public License, version 2.0, as published by the
|
|
Free Software Foundation.
|
|
|
|
This program is also distributed with certain software (including but not
|
|
limited to OpenSSL) that is licensed under separate terms, as designated in a
|
|
particular file or component or in included license documentation. The authors
|
|
of MySQL hereby grant you an additional permission to link the program and
|
|
your derivative works with the separately licensed software that they have
|
|
included with MySQL.
|
|
|
|
This program is distributed in the hope that it will be useful, but WITHOUT
|
|
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
|
FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
|
|
for more details.
|
|
|
|
You should have received a copy of the GNU General Public License along with
|
|
this program; if not, write to the Free Software Foundation, Inc.,
|
|
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
|
*****************************************************************************/
|
|
|
|
/** @file include/row0ext.ic
|
|
Caching of externally stored column prefixes
|
|
|
|
Created September 2006 Marko Makela
|
|
*******************************************************/
|
|
|
|
#include "btr0types.h"
|
|
#include "rem0types.h"
|
|
|
|
/** Looks up a column prefix of an externally stored column.
|
|
@return column prefix, or NULL if the column is not stored externally,
|
|
or pointer to field_ref_zero if the BLOB pointer is unset */
|
|
UNIV_INLINE
|
|
const byte *row_ext_lookup_ith(
|
|
const row_ext_t *ext, /*!< in/out: column prefix cache */
|
|
ulint i, /*!< in: index of ext->ext[] */
|
|
ulint *len) /*!< out: length of prefix, in bytes,
|
|
at most ext->max_len */
|
|
{
|
|
ut_ad(ext);
|
|
ut_ad(len);
|
|
ut_ad(i < ext->n_ext);
|
|
|
|
*len = ext->len[i];
|
|
|
|
ut_ad(*len <= ext->max_len);
|
|
ut_ad(ext->max_len > 0);
|
|
|
|
if (*len == 0) {
|
|
/* The BLOB could not be fetched to the cache. */
|
|
return (field_ref_zero);
|
|
} else {
|
|
return (ext->buf + i * ext->max_len);
|
|
}
|
|
}
|
|
|
|
/** Looks up a column prefix of an externally stored column.
|
|
@return column prefix, or NULL if the column is not stored externally,
|
|
or pointer to field_ref_zero if the BLOB pointer is unset */
|
|
UNIV_INLINE
|
|
const byte *row_ext_lookup(const row_ext_t *ext, /*!< in: column prefix cache */
|
|
ulint col, /*!< in: column number in the InnoDB
|
|
table object, as reported by
|
|
dict_col_get_no(); NOT relative to the
|
|
records in the clustered index */
|
|
ulint *len) /*!< out: length of prefix, in bytes,
|
|
at most ext->max_len */
|
|
{
|
|
ulint i;
|
|
|
|
ut_ad(ext);
|
|
ut_ad(len);
|
|
|
|
for (i = 0; i < ext->n_ext; i++) {
|
|
if (col == ext->ext[i]) {
|
|
return (row_ext_lookup_ith(ext, i, len));
|
|
}
|
|
}
|
|
|
|
return (NULL);
|
|
}
|