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diff --git a/storage/innobase/ha/ha0storage.c b/storage/innobase/ha/ha0storage.c
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+/*****************************************************************************
+
+Copyright (c) 2007, 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 ha/ha0storage.c
+Hash storage.
+Provides a data structure that stores chunks of data in
+its own storage, avoiding duplicates.
+
+Created September 22, 2007 Vasil Dimov
+*******************************************************/
+
+#include "univ.i"
+#include "ha0storage.h"
+#include "hash0hash.h"
+#include "mem0mem.h"
+#include "ut0rnd.h"
+
+#ifdef UNIV_NONINL
+#include "ha0storage.ic"
+#endif
+
+/*******************************************************************//**
+Retrieves a data from a storage. If it is present, a pointer to the
+stored copy of data is returned, otherwise NULL is returned. */
+static
+const void*
+ha_storage_get(
+/*===========*/
+	ha_storage_t*	storage,	/*!< in: hash storage */
+	const void*	data,		/*!< in: data to check for */
+	ulint		data_len)	/*!< in: data length */
+{
+	ha_storage_node_t*	node;
+	ulint			fold;
+
+	/* avoid repetitive calls to ut_fold_binary() in the HASH_SEARCH
+	macro */
+	fold = ut_fold_binary(data, data_len);
+
+#define IS_FOUND	\
+	node->data_len == data_len && memcmp(node->data, data, data_len) == 0
+
+	HASH_SEARCH(
+		next,			/* node->"next" */
+		storage->hash,		/* the hash table */
+		fold,			/* key */
+		ha_storage_node_t*,	/* type of node->next */
+		node,			/* auxiliary variable */
+		,			/* assertion */
+		IS_FOUND);		/* search criteria */
+
+	if (node == NULL) {
+
+		return(NULL);
+	}
+	/* else */
+
+	return(node->data);
+}
+
+/*******************************************************************//**
+Copies data into the storage and returns a pointer to the copy. If the
+same data chunk is already present, then pointer to it is returned.
+Data chunks are considered to be equal if len1 == len2 and
+memcmp(data1, data2, len1) == 0. If "data" is not present (and thus
+data_len bytes need to be allocated) and the size of storage is going to
+become more than "memlim" then "data" is not added and NULL is returned.
+To disable this behavior "memlim" can be set to 0, which stands for
+"no limit". */
+UNIV_INTERN
+const void*
+ha_storage_put_memlim(
+/*==================*/
+	ha_storage_t*	storage,	/*!< in/out: hash storage */
+	const void*	data,		/*!< in: data to store */
+	ulint		data_len,	/*!< in: data length */
+	ulint		memlim)		/*!< in: memory limit to obey */
+{
+	void*			raw;
+	ha_storage_node_t*	node;
+	const void*		data_copy;
+	ulint			fold;
+
+	/* check if data chunk is already present */
+	data_copy = ha_storage_get(storage, data, data_len);
+	if (data_copy != NULL) {
+
+		return(data_copy);
+	}
+
+	/* not present */
+
+	/* check if we are allowed to allocate data_len bytes */
+	if (memlim > 0
+	    && ha_storage_get_size(storage) + data_len > memlim) {
+
+		return(NULL);
+	}
+
+	/* we put the auxiliary node struct and the data itself in one
+	continuous block */
+	raw = mem_heap_alloc(storage->heap,
+			     sizeof(ha_storage_node_t) + data_len);
+
+	node = (ha_storage_node_t*) raw;
+	data_copy = (byte*) raw + sizeof(*node);
+
+	memcpy((byte*) raw + sizeof(*node), data, data_len);
+
+	node->data_len = data_len;
+	node->data = data_copy;
+
+	/* avoid repetitive calls to ut_fold_binary() in the HASH_INSERT
+	macro */
+	fold = ut_fold_binary(data, data_len);
+
+	HASH_INSERT(
+		ha_storage_node_t,	/* type used in the hash chain */
+		next,			/* node->"next" */
+		storage->hash,		/* the hash table */
+		fold,			/* key */
+		node);			/* add this data to the hash */
+
+	/* the output should not be changed because it will spoil the
+	hash table */
+	return(data_copy);
+}
+
+#ifdef UNIV_COMPILE_TEST_FUNCS
+
+void
+test_ha_storage()
+{
+	ha_storage_t*	storage;
+	char		buf[1024];
+	int		i;
+	const void*	stored[256];
+	const void*	p;
+
+	storage = ha_storage_create(0, 0);
+
+	for (i = 0; i < 256; i++) {
+
+		memset(buf, i, sizeof(buf));
+		stored[i] = ha_storage_put(storage, buf, sizeof(buf));
+	}
+
+	//ha_storage_empty(&storage);
+
+	for (i = 255; i >= 0; i--) {
+
+		memset(buf, i, sizeof(buf));
+		p = ha_storage_put(storage, buf, sizeof(buf));
+
+		if (p != stored[i]) {
+
+			fprintf(stderr, "ha_storage_put() returned %p "
+				"instead of %p, i=%d\n", p, stored[i], i);
+			return;
+		}
+	}
+
+	fprintf(stderr, "all ok\n");
+
+	ha_storage_free(storage);
+}
+
+#endif /* UNIV_COMPILE_TEST_FUNCS */