Data Structures | Typedefs | Functions
picotm-lib-shared-treemap.h File Reference

Contains struct picotm_shared_treemap and helper functions. More...

#include <stdatomic.h>
#include <stdint.h>
#include "compiler.h"

Data Structures

struct  picotm_shared_treemap
 Maps keys to values. More...


typedef uintptr_t(* picotm_shared_treemap_value_create_function) (unsigned long long key, struct picotm_shared_treemap *treemap, struct picotm_error *error)
typedef void(* picotm_shared_treemap_value_destroy_function) (uintptr_t value, struct picotm_shared_treemap *treemap)


PICOTM_NOTHROW uintptr_t picotm_shared_treemap_find_value (struct picotm_shared_treemap *self, unsigned long long key, picotm_shared_treemap_value_create_function value_create, picotm_shared_treemap_value_destroy_function value_destroy, struct picotm_error *error)
PICOTM_NOTHROW void picotm_shared_treemap_init (struct picotm_shared_treemap *self, unsigned long key_nbits, unsigned long level_nbits)
PICOTM_NOTHROW void picotm_shared_treemap_uninit (struct picotm_shared_treemap *self, picotm_shared_treemap_value_destroy_function value_destroy)

Detailed Description

The data stucture struct picotm_shared_treemap maps keys to values. Concurrent look-up by multiple transactions is supported. Keys can be up to 64 bit in length, values are of type uintptr_t, so unsigned integers or pointers can be stored.

Initialize a shared treemap with a call to picotm_shared_treemap_init().

picotm_shared_treemap_init(&treemap, 52, 13);

The second parameter is the maximum number of bits in a key. The initializer function sets up the shared treemap instance to support keys up to this length. Using larger keys is undefined. The third argument is the number of key bits handled per level of the internal tree hierarchy. Ideally this number is a remainder-free divider of the key length.

Call picotm_shared_treemap_find_value() to retrieve a key's value from the shared treemap. If the key/value pair is not in the shared treemap, a creator function can generate a new value as part of the lookup. If you don't provide a creator function, 0 is returned for non-existing values.

The following example returns the value for the key 0x1234 from the shared treemap, or inserts a new value if the key/value pair is not present.

// creator function
create_value(unsigned long long key,
struct picotm_shared_treemap* treemap,
struct picotm_error* error)
int* value = malloc(sizeof(*value));
if (!value) {
picotm_set_error_code(error, PICOTM_OUT_OF_MEMORY);
return 0;
*value = 0;
return (uintptr_t)value;
// destroy function
destroy_value(uintptr_t value, struct picotm_shared_treemap* treemap)
struct picotm_error error;
int* value = (int*)picotm_shared_treemap_find_value(treemap, 0x1234,
// perform error recovery

To uninitialize a shared treemap, call picotm_shared_treemap_uninit(). This function requires a destroy function for the values. It walk over all keys in the shared treemap and invokes the destroy function on each key's value.

picotm_shared_treemap_uninit(&treemap, destroy_value);

Typedef Documentation

◆ picotm_shared_treemap_value_create_function

typedef uintptr_t(* picotm_shared_treemap_value_create_function) (unsigned long long key, struct picotm_shared_treemap *treemap, struct picotm_error *error)

Invoked by picotm's shared treemap to create a new shared value.

keyThe value's key.
treemapThe value's shared treemap.
[out]errorReturns an error from the creator function.
A pointer to the created value.

◆ picotm_shared_treemap_value_destroy_function

typedef void(* picotm_shared_treemap_value_destroy_function) (uintptr_t value, struct picotm_shared_treemap *treemap)

Invoked by picotm's shared treemap to destroy a value.

valueThe value to destroy.
treemapThe value's shared treemap.

Function Documentation

◆ picotm_shared_treemap_find_value()

PICOTM_NOTHROW uintptr_t picotm_shared_treemap_find_value ( struct picotm_shared_treemap self,
unsigned long long  key,
picotm_shared_treemap_value_create_function  value_create,
picotm_shared_treemap_value_destroy_function  value_destroy,
struct picotm_error error 

Retrieves the value for a key from a shared treemap.

selfThe shared treemap.
keyThe value's key.
value_createThe creator function for shared values.
value_destroyThe destroy function for shared values.
[out]errorReturns an error from the look-up function.
The key's element.

◆ picotm_shared_treemap_init()

PICOTM_NOTHROW void picotm_shared_treemap_init ( struct picotm_shared_treemap self,
unsigned long  key_nbits,
unsigned long  level_nbits 

Initializes a shared treemap.

selfThe shared treemap to initialize.
key_nbitsThe maximum number of bits per key.
level_nbitsThe number of bits per directory level.

◆ picotm_shared_treemap_uninit()

PICOTM_NOTHROW void picotm_shared_treemap_uninit ( struct picotm_shared_treemap self,
picotm_shared_treemap_value_destroy_function  value_destroy 

Uninitializes a shared treemap.

selfThe shared treemap to initialize.
value_destroyThe destroy function for shared values.