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What's qLibc? Actions Status

qLibc is currently one of the most functionally-complete, publicly-licensed C/C++ libraries. The goal of the qLibc project is to provide a simple and powerful general purpose C/C++ library that includes all kinds of containers and general library routines. It provides a ready-made set of common container APIs with a consistent API look.

qLibc Copyright

qLibc is published under 2-clause BSD license known as Simplified BSD License. Please refer the LICENSE document included in the package for more details.

API Reference

  • qlibc Core API Reference

    • Containers for Key/Value pairs
      • Tree Table --- in binary tree(left-leaning red-black tree) data structure.
      • Hash Table --- in hash-based data structure.
      • Static Hash Table --- in fixed size memory(array/mmapped/shared).
      • List Table --- in (doubly) linked-list data structure.
    • Containers for Objects
      • List --- Doubly Linked List.
      • Vector --- implements a growable array of elements.
      • Queue --- FIFO(First In First Out) implementation.
      • Stack --- LIFO(Last In First Out) implementation.
    • General utilities.
      • String --- string trimmer, modifier, replacer, case converter, pattern detectors, ...
      • I/O --- non-blocking I/O, stream reader/writer, ...
      • File --- file locking, file/directory hander, path correctors, ...
      • IPC, Semaphore Shared-memory
      • En/decoders --- Url en/decoder, Base64 en/decoder, Hex en/decoder, ...
      • Hashes --- Murmur hases, FNV hases, MD5 hashes, ...
      • Time --- time diff, time format converstion, ...
  • qLibc Extension API Reference

    • Apache-style Configuration File Parser.
    • INI-style Configuration File Parser.
    • HTTP client.
    • Rotating File Logger.
    • Database(MySQL) interface.
    • Token-Bucket

qLibc Tables at a Glance

Characteristics Tree Table Hash Table Static Hash Table List Table
Data structure Binary Tree Slot Index Block Array Linked-List
Search complexity O(log n) O(1) / O(n) O(1) / O(n) O(n)
Insert complexity O(log n) O(1) / O(n) O(1) / O(n) O(1)
Delete complexity O(log n) O(1) / O(n) O(1) / O(n) O(n)
Space complexity O(n) O(n) - O(n)
Space allocation Dynamic Dynamic Pre-allocation Dynamic
Key Stored Sorted Yes No No Yes (option)
User comparator Supported - - Supported
Duplicated keys No No No Yes (option)
Key stored digested No No Yes No
Search Nearest Key Yes No No No
Iterator support Yes Yes Yes Yes
Iterator visit order min -> max random random insert order
Thread-safe option Supported Suported User Supported
Can use shared mem No No Yes No

Consistent API Look

All container APIs have a consistent look and feel. It basically provides a creator function which usually returns a pointer to a container structure. Also, all functions related to the container can be accessed through function pointers inside of the container or traditional style direct access APIs. For an example,

So, regardless of which container you use, you can simply put elements into a list with container->put(container, ...) or you can call them using direct API like qtreetbl_pub(container, ...).

An examples below illustrates how it looks like.

  // create a hash-table.
  qhashtbl_t *tbl = qhashtbl(0, QHASHTBL_THREADSAFE);
  // add an element which key name is "score".
  int x = 12345;
  tbl->put(tbl, "score", &x, sizeof(int));
  // get the value of the element.
  int *px = tbl->get(tbl, "score", NULL, true);
  if(px != NULL) {
    printf("%d\n", *px);
  // release table

Here is an identical implementation with a Linked-List-Table container. You may notice that there aren't any code changes at all, except for 1 line in the table creation. This is why qLibc encapsulates corresponding function pointers inside of the container object.

  // create a linked-list-table. THE ONLY LINE YOU NEED TO CHANGE.
  qlisttbl_t *tbl = qlisttbl(QLISTTBL_THREADSAFE);
  // add an element which key name is "score".
  int x = 12345;
  tbl->put(tbl, "score", &x, sizeof(int));
  // get the value of the element.
  int *px = tbl->get(tbl, "score", NULL, true);
  if(px != NULL) {
    printf("%d\n", *px);             
  // release table

Looking for people to work with.

We're looking for people who want to work together to develop and improve qLibc. Currently, we have high demands on following areas.

  • Automated testing
  • Documentation.
  • New feature implementation.


The following people have helped with suggestions, ideas, code or fixing bugs: (in alphabetical order by first name)

If we have forgotten or misspelled your name, please let us know.