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diff --git a/storage/xtradb/include/row0ext.ic b/storage/xtradb/include/row0ext.ic
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+++ b/storage/xtradb/include/row0ext.ic
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+/*****************************************************************************
+
+Copyright (c) 2006, 2009, Innobase Oy. 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 as published by the Free Software
+Foundation; version 2 of the License.
+
+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 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., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+
+*****************************************************************************/
+
+/**************************************************//**
+@file include/row0ext.ic
+Caching of externally stored column prefixes
+
+Created September 2006 Marko Makela
+*******************************************************/
+
+#include "rem0types.h"
+#include "btr0types.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 (UNIV_UNLIKELY(*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);
+}