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);