MySQL 8.0.31
Source Code Documentation
ha0storage.h File Reference

Hash storage. More...

#include "univ.i"
#include "ha0storage.ic"

Go to the source code of this file.

Functions

static ha_storage_tha_storage_create (ulint initial_heap_bytes, ulint initial_hash_cells)
 Creates a hash storage. More...
 
const void * ha_storage_put_memlim (ha_storage_t *storage, const void *data, ulint data_len, ulint memlim)
 Copies data into the storage and returns a pointer to the copy. More...
 
static const void * ha_storage_put (ha_storage_t *storage, const void *data, ulint data_len)
 Same as ha_storage_put_memlim() but without memory limit. More...
 
static const char * ha_storage_put_str (ha_storage_t *storage, const char *str)
 Copies string into the storage and returns a pointer to the copy. More...
 
static const char * ha_storage_put_str_memlim (ha_storage_t *storage, const char *str, ulint memlim)
 Copies string into the storage and returns a pointer to the copy obeying a memory limit. More...
 
static void ha_storage_empty (ha_storage_t **storage)
 Empties a hash storage, freeing memory occupied by data chunks. More...
 
static void ha_storage_free (ha_storage_t *storage)
 Frees a hash storage and everything it contains, it cannot be used after this call. More...
 
static ulint ha_storage_get_size (const ha_storage_t *storage)
 Gets the size of the memory used by a storage. More...
 

Variables

constexpr uint32_t HA_STORAGE_DEFAULT_HEAP_BYTES = 1024
 This value is used by default by ha_storage_create(). More...
 
constexpr uint32_t HA_STORAGE_DEFAULT_HASH_CELLS = 4096
 This value is used by default by ha_storage_create(). More...
 

Detailed Description

Hash storage.

Provides a data structure that stores chunks of data in its own storage, avoiding duplicates.

Created September 22, 2007 Vasil Dimov

Function Documentation

◆ ha_storage_create()

static ha_storage_t * ha_storage_create ( ulint  initial_heap_bytes,
ulint  initial_hash_cells 
)
inlinestatic

Creates a hash storage.

If any of the parameters is 0, then a default value is used.

Parameters
[in]initial_hash_cellsinitial number of cells in the hash table
[in]initial_heap_bytesinitial heap's size
Returns
own: hash storage

◆ ha_storage_empty()

static void ha_storage_empty ( ha_storage_t **  storage)
inlinestatic

Empties a hash storage, freeing memory occupied by data chunks.

This invalidates any pointers previously returned by ha_storage_put(). The hash storage is not invalidated itself and can be used again. in/out: hash storage

◆ ha_storage_free()

static void ha_storage_free ( ha_storage_t storage)
inlinestatic

Frees a hash storage and everything it contains, it cannot be used after this call.

This invalidates any pointers previously returned by ha_storage_put(). in, own: hash storage

◆ ha_storage_get_size()

static ulint ha_storage_get_size ( const ha_storage_t storage)
inlinestatic

Gets the size of the memory used by a storage.

Returns
bytes used in: hash storage

◆ ha_storage_put()

static const void * ha_storage_put ( ha_storage_t storage,
const void *  data,
ulint  data_len 
)
inlinestatic

Same as ha_storage_put_memlim() but without memory limit.

Parameters
storagein/out: hash storage
datain: data to store
data_lenin: data length
Returns
pointer to the copy of the string

◆ ha_storage_put_memlim()

const void * ha_storage_put_memlim ( ha_storage_t storage,
const void *  data,
ulint  data_len,
ulint  memlim 
)

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".

Returns
pointer to the copy in: memory limit to obey

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".

Parameters
storagein/out: hash storage
datain: data to store
data_lenin: data length
memlimin: memory limit to obey

◆ ha_storage_put_str()

static const char * ha_storage_put_str ( ha_storage_t storage,
const char *  str 
)
inlinestatic

Copies string into the storage and returns a pointer to the copy.

If the same string is already present, then pointer to it is returned. Strings are considered to be equal if strcmp(str1, str2) == 0.

Parameters
storagein/out: hash storage
strin: string to put
Returns
pointer to the copy of the string

◆ ha_storage_put_str_memlim()

static const char * ha_storage_put_str_memlim ( ha_storage_t storage,
const char *  str,
ulint  memlim 
)
inlinestatic

Copies string into the storage and returns a pointer to the copy obeying a memory limit.

If the same string is already present, then pointer to it is returned. Strings are considered to be equal if strcmp(str1, str2) == 0.

Parameters
storagein/out: hash storage
strin: string to put
memlimin: memory limit to obey
Returns
pointer to the copy of the string

Variable Documentation

◆ HA_STORAGE_DEFAULT_HASH_CELLS

constexpr uint32_t HA_STORAGE_DEFAULT_HASH_CELLS = 4096
constexpr

This value is used by default by ha_storage_create().

It is a constant per ha_storage's lifetime.

◆ HA_STORAGE_DEFAULT_HEAP_BYTES

constexpr uint32_t HA_STORAGE_DEFAULT_HEAP_BYTES = 1024
constexpr

This value is used by default by ha_storage_create().

More memory is allocated later when/if it is needed.