libcritnib

NAME

libcritnib - an ordered map data structure with lock-free reads

SYNOPSIS

#include <critnib.h>

Link with -lcritnib.

DESCRIPTION

Functions:

critnib *critnib_new(void);

Creates a new empty critnib structure.

void critnib_delete(critnib *c);

Destroys and frees the memory. Note that removed items are reused but won’t have their memory freed until this function is called.

int critnib_insert(critnib *c, uintptr_t key, void *value, int update);

Adds a key:value pair to the critnib structure. If update is non-zero, an already existing key has its value updated, otherwise the function returns EEXIST . It may return ENOMEM if we’re out of memory, or 0 if all went okay.

void *critnib_remove(critnib *c, uintptr_t key);

Removes a given key from the structure. Its associated value is returned, or 0 ( NULL ) if there was no such key.

void *critnib_get(critnib *c, uintptr_t key);

Obtains a value for a given key, or 0 ( NULL ) if not present.

void *critnib_find_le(critnib *c, uintptr_t key);

Searches for the largest key not exceeding the argument, and returns its value.

int critnib_find(critnib *c, uintptr_t key, enum find_dir_t dir, uintptr_t
*rkey, void **rvalue);

Searches for a key that’s smaller ( FIND_L ), smaller-or-equal ( FIND_LE ), equal ( FIND_EQ ), greater-or-equal ( FIND_GE ), or greater ( FIND_G ) than the argument. If found, the key and value are assigned to *rkey and *rvalue (which may be null to skip assignment), and 1 is returned.

void critnib_iter(critnib *c, uintptr_t min, uintptr_t max, func, void
*privdata);

Walks the structure, visiting all entries whose keys are at least min but no larger than max (give -1 for no max), calling func for every entry found. If the func returns a non-zero value, the walk is aborted.

The prototype for func should be: int (*func)(uintptr_t key, void *value, void *privdata); where privdata is an optional value passed to the iterator.

NB. This version of the library implements the iterator in a crude blocking way, stalling any concurrent writers and iterators. This limitation will be lifted in the future.