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87 lines
2.7 KiB
C++
87 lines
2.7 KiB
C++
/*****************************************************************************
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Copyright (c) 2006, 2009, Oracle and/or its affiliates. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/**************************************************//**
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@file include/row0ext.ic
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Caching of externally stored column prefixes
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Created September 2006 Marko Makela
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*******************************************************/
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#include "rem0types.h"
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#include "btr0types.h"
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/********************************************************************//**
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Looks up a column prefix of an externally stored column.
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@return column prefix, or NULL if the column is not stored externally,
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or pointer to field_ref_zero if the BLOB pointer is unset */
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UNIV_INLINE
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const byte*
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row_ext_lookup_ith(
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/*===============*/
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const row_ext_t* ext, /*!< in/out: column prefix cache */
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ulint i, /*!< in: index of ext->ext[] */
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ulint* len) /*!< out: length of prefix, in bytes,
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at most ext->max_len */
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{
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ut_ad(ext);
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ut_ad(len);
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ut_ad(i < ext->n_ext);
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*len = ext->len[i];
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ut_ad(*len <= ext->max_len);
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ut_ad(ext->max_len > 0);
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if (*len == 0) {
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/* The BLOB could not be fetched to the cache. */
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return(field_ref_zero);
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} else {
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return(ext->buf + i * ext->max_len);
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}
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}
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/********************************************************************//**
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Looks up a column prefix of an externally stored column.
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@return column prefix, or NULL if the column is not stored externally,
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or pointer to field_ref_zero if the BLOB pointer is unset */
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UNIV_INLINE
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const byte*
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row_ext_lookup(
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/*===========*/
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const row_ext_t* ext, /*!< in: column prefix cache */
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ulint col, /*!< in: column number in the InnoDB
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table object, as reported by
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dict_col_get_no(); NOT relative to the
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records in the clustered index */
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ulint* len) /*!< out: length of prefix, in bytes,
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at most ext->max_len */
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{
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ulint i;
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ut_ad(ext);
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ut_ad(len);
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for (i = 0; i < ext->n_ext; i++) {
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if (col == ext->ext[i]) {
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return(row_ext_lookup_ith(ext, i, len));
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}
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}
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return(NULL);
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}
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