vsync / map / treeset_rb_coarse.h

This implementation of treeset uses balanced red-black tree (RB) and coarse-grained locking.

Groups: Linearizable

Refer to treeset_bst_coarse.h for more general information about treeset.

Example:

#define TREESET_LOCK_RW
#include <vsync/map/treeset_rb_coarse.h>

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>

#define N       4
#define MIN_KEY 0
#define MAX_KEY 3

typedef vuintptr_t value_t;

treeset_t tree;

void *
run(void *args)
{
    vsize_t tid = (vsize_t)args;

    for (treeset_key_t key = MIN_KEY; key <= MAX_KEY; key++) {
        value_t value = tid;
        value_t old_value;

        // insert
        vbool_t res =
            treeset_add(&tree, key, (void *)value, (void *)&old_value);

        if (res) {
            // insert succeeded
            printf("[%lu] key %lu inserted\n", tid, key);
        } else {
            printf(
                "[%lu] key %lu not inserted, already in tree with value %lu\n",
                tid, key, old_value);
        }

        // search
        res = treeset_contains(&tree, key, (void *)&old_value);

        if (res) {
            // search successful
            printf("[%lu] key %lu in tree with value %lu\n", tid, key,
                   old_value);
        } else {
            printf("[%lu] key %lu not in tree\n", tid, key);
        }

        // remove
        res = treeset_remove(&tree, key, (void *)&old_value);

        if (res) {
            // remove succeeded
            printf("[%lu] key %lu removed, old value was %lu\n", tid, key,
                   old_value);
        } else {
            printf("[%lu] key %lu not removed\n", tid, key);
        }
    }

    return NULL;
}

void *
malloc_cb(vsize_t sz, void *arg)
{
    (void)arg;
    return malloc(sz);
}

void
free_cb(void *ptr, void *arg)
{
    (void)arg;
    free(ptr);
}

void
free_visitor(treeset_key_t key, void *value, void *arg)
{
    (void)key;
    (void)arg;
    free((value_t *)value);
}

int
main(void)
{
    pthread_t threads[N];

    vmem_lib_t mem_lib = {.free_fun   = free_cb,
                          .malloc_fun = malloc_cb,
                          .arg        = NULL};

    treeset_init(&tree, mem_lib);

    for (vsize_t i = 0; i < N; ++i) {
        pthread_create(&threads[i], NULL, run, (void *)i);
    }

    for (vsize_t i = 0; i < N; ++i) {
        pthread_join(threads[i], NULL);
    }

    treeset_visit(&tree, free_visitor, NULL);
    treeset_destroy(&tree);

    return 0;
}

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Functions

Function	Description
treeset_init	Initializes the treeset.
treeset_destroy	Destroys all the remaining nodes in the treeset.
treeset_add	Attempts to insert an element with a given key and value into the treeset.
treeset_remove	Attempts to remove an element with a given key from the treeset.
treeset_contains	Searches the treeset for an element with a given key.
treeset_visit	Visits all elements in the treeset.

Function treeset_init

static void treeset_init(treeset_t *tree, vmem_lib_t mem_lib)

Initializes the treeset.

Note: must be called before threads access the treeset.

Parameters:

• tree: address of the treeset_t object.
• mem_lib: object of type vmem_lib_t containing malloc/free functions to allocate/free internal nodes.

Function treeset_destroy

static void treeset_destroy(treeset_t *tree)

Destroys all the remaining nodes in the treeset.

Note: call only after thread join, or after all threads finished accessing the treeset.

Parameters:

• tree: address of the treeset_t object.

Function treeset_add

static vbool_t treeset_add(treeset_t *tree, treeset_key_t key, void *value, void **out_value)

Attempts to insert an element with a given key and value into the treeset.

Parameters:

• tree: address of the treeset_t object.
• key: the key to be inserted.
• value: value to be associated with inserted key.
• out_value: out parameter for the previous value associated with the key.

Returns: true operation succeeded.

Returns: false operation failed, since the given key was already in the treeset, in the out_value the value of this element is returned.

Function treeset_remove

static vbool_t treeset_remove(treeset_t *tree, treeset_key_t key, void **out_value)

Attempts to remove an element with a given key from the treeset.

Parameters:

• tree: address of the treeset_t object.
• key: the key to be removed.
• out_value: out parameter for the value associated with the key.

Returns: true operation succeeded, in the out_value the value of the removed element is returned.

Returns: false operation failed, there is no element with the given key.

Function treeset_contains

static vbool_t treeset_contains(treeset_t *tree, treeset_key_t key, void **out_value)

Searches the treeset for an element with a given key.

Parameters:

• tree: address of the treeset_t object.
• key: the key to be searched for.
• out_value: out parameter for the value associated with the key.

Returns: true operation succeeded, in the out_value the value of the found element is returned.

Returns: false operation failed, there is no element with the given key.

Function treeset_visit

static void treeset_visit(treeset_t *tree, treeset_visitor visitor, void *arg)

Visits all elements in the treeset.

Note: call only after thread join, or after all threads finished accessing the treeset.

Parameters:

• tree: address of the treeset_t object.
• visitor: address of the function to call on each element.
• arg: the third argument to the visitor function.

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