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_t *	ha_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_cells	initial number of cells in the hash table
[in]	initial_heap_bytes	initial 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

storage	in/out: hash storage
data	in: data to store
data_len	in: 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

storage	in/out: hash storage
data	in: data to store
data_len	in: data length
memlim	in: 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

storage	in/out: hash storage
str	in: 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

storage	in/out: hash storage
str	in: string to put
memlim	in: 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.