diff options
Diffstat (limited to 'storage/innobase/ha/ha0storage.cc')
| -rw-r--r-- | storage/innobase/ha/ha0storage.cc | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/storage/innobase/ha/ha0storage.cc b/storage/innobase/ha/ha0storage.cc new file mode 100644 index 00000000..acde71b0 --- /dev/null +++ b/storage/innobase/ha/ha0storage.cc @@ -0,0 +1,178 @@ +/***************************************************************************** + +Copyright (c) 2007, 2016, Oracle and/or its affiliates. All Rights Reserved. +Copyright (c) 2020, MariaDB Corporation. + +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., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA + +*****************************************************************************/ + +/**************************************************//** +@file ha/ha0storage.cc +Hash storage. +Provides a data structure that stores chunks of data in +its own storage, avoiding duplicates. + +Created September 22, 2007 Vasil Dimov +*******************************************************/ + +#include "ha0storage.h" +#include "hash0hash.h" +#include "mem0mem.h" +#include "ut0rnd.h" + +/*******************************************************************//** +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(static_cast<const byte*>(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". */ +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(static_cast<const byte*>(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]) { + ib::warn() << "ha_storage_put() returned " << p + << " instead of " << stored[i] << ", i=" << i; + return; + } + } + + ib::info() << "all ok"; + + ha_storage_free(storage); +} + +#endif /* UNIV_COMPILE_TEST_FUNCS */ |