Complexity is a GNU utility to calculate the complexity of a C program. It’s similar to the McCabe scoring (ref tool: pmccabe) with extra considerations on the scoring scheme. Complexity can be used as a means to analyze a C program and detect areas to improve or simplify or the amount of effort required to understand a piece of code. Complexity is written in C.
Information from complexity analysis help to:
- locate suspicious areas in unfamiliar code
- get an idea of how much effort may be required to understand that code
- get an idea of the effort required to test a code base
- a measure of how easy it is for others to underand your own code
Complexity considers the following additional aspects compared to pmccabe:
- code length
- switch statement
- logic conditions
- author’s personal experience
- rationale summary
Code complexity computation involves several parsing methods and a robust complexity measurement algorithm.
Installation
Download the code and install it:
$ sudo apt-get install autogen
$ tar -xvf complexity-version.tar.xz
$ cd complexity-version
$ make
$ sudo make install
Usage
A sample run of complexity on dslib:
$ complexity --histogram --score --thresh=3 *.c
Complexity Scores
Score | ln-ct | nc-lns| file-name(line): proc-name
6 43 35 tree.c(94): insert_tree_node
9 59 52 avl.c(136): rebalance
9 65 55 avl.c(362): delete_avl_node
10 75 52 avl.c(492): search_BFS_avl
10 75 52 tree.c(268): search_BFS
15 66 53 tree.c(144): delete_tree_node
17 88 61 tree.c(358): search_DFS
23 87 61 avl.c(267): insert_avl_node
Complexity Histogram
Score-Range Lin-Ct
0-9 142 ***************************************
10-19 218 ************************************************************
20-29 61 *****************
Scored procedure ct: 8
Non-comment line ct: 421
Average line score: 13
25%-ile score: 9 (75% in higher score procs)
50%-ile score: 10 (half in higher score procs)
75%-ile score: 17 (25% in higher score procs)
Highest score: 23 (insert_avl_node() in avl.c)
Score meanings
For further help, run:
$ complexity --help
Complexity scale
0-9 : Easily maintained code 10-19 : Maintained with little trouble 20-29 : Maintained with some effort 30-39 : Difficult to maintain code 40-49 : Hard to maintain code 50-99 : Unmaintainable code 100-199: Crazy making difficult code 200+ : I only wish I were kidding
