complexity

NAME

complexity - Measure complexity of C source

SYNOPSIS

complexity [-flags] [-flag [value]] [--option-name[[=| ]value]] [ <file-name> ... ]

The operands that this program operates on may be specified either on the command line or read from standard input, one per line. In that input, leading and trailing white space is stripped, blank lines are ignored. Standard input may not be a terminal.

Compute the complexity of source code not just with a path-through-the-code count, but also amplifying line counts by logic level nesting.

Compute the complexity of code by counting lines of non-comment source and multiplying by a nested logic weight factor. By default, 1.9.

DESCRIPTION

The weight of each statement is the number of lines the statement uses. This value is multiplied by the nested logic weighting (1.9 by default) for each layer of logic. For example, this snippet:

if (foo) {
if (bar) {
bumble; baz;
}
}

will score 11. This score is then scaled to approximate pmccabe results by dividing by 20 and rounding. This scores "1" at the end. pmccabe scores higher on simple procedures and complexity scores higher with more deeply nested logic.

The scoring can be tweaked by adjusting the --nesting-penalty and --scale-ing factors. The default values were calibrated by comparing the average results of millions of lines of code with the results of pmccabe.

For the purposes of this program, a procedure is identified by a name followed by a parenthesized expression and then an opening curly brace. It ends with a closing curly brace in column 1.

This program will perform its function for every file named on the command line or every file named in a list read from stdin. The arguments or input names must be pre-existing files. The input list may contain comments, which are blank lines or lines beginning with a ’#’ character.

OPTIONS

-t minimum, --threshold=minimum Reporting threshold. This option takes an
integer number as its argument. The default minimum for this option is:
30

Ignore any procedures with a complexity measure below this threshold. By
default, a complexity score of under 30 is not printed. However, if a
histogram and statistics are to be printed, but not individual procedure
scores, then the default is set to zero. Procedures below this limit are
not counted in the statistics.

--horrid-threshold=minimum zero exit threshold. This option takes an
integer number as its argument. The default minimum for this option is:
100

If any procedures score higher than this threshold, then the program will
exit non-zero. (4/COMPLEX_EXIT_HORRID_FUNCTION, if no other problems are
encountered.) By default, this program exits zero unless one function
exceeds the horrid score of 100.

-n factor, --nesting-penalty=factor score multiplier for nested code.

Linguistic constructs weigh more heavily the more deeply nested they are.
By default, each layer penalizes by a factor of 1.9. The option argument
is a floating point number. The penalty may be 1, but not less.

--demi-nesting-penalty=factor score multiplier for nested expressions.

By default, this value is halfway between 1.0 and the nesting penalty
(specifically, the square root of the nesting penalty). It refers to a
parenthesized sub-expression. e.g.
((a > b) && (c > d))
contains two parenthesized sub-expressions. This would count 3.5 points.
On the other hand, this:
(a > b && c > d)
contains two relation operators and a logical operator at the same level.
These nested counts will be multiplied together and yield 2.5 * 2.5, or
6.25. Don’t do that. It gets even worse if you have logical ands and ors
at the same level.

-s factor, --scale=factor complexity scaling factor. This option takes an
integer number as its argument.

By default, the scaling is 20 which divides the raw score by 20. This was
normalized to roughly correspond to the pmccabe scores:

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.
Score | ln-ct | nc-lns| file-name(line): proc-name
4707 3815 2838 lib/vasnprintf.c(1747): VASNPRINTF

-h, --histogram, --no-histogram Display histogram of complexity numbers.
The no-histogram form will disable the option. This option may not be
preset with environment variables or in initialization (rc) files.

Instead of printing out each function’s score, a summary is printed at the
end showing how many functions had particular ranges of scores. Unless
--scores is specifically called out, the scores will not print with this
option specified. The minimum scoring threshold will also be reduced to
zero (0), unless --threshold is specified.

-c, --scores, --no-scores Display the score for each procedure. The
no-scores form will disable the option. This option may not be preset with
environment variables or in initialization (rc) files.

If you specify --histogram, individual scores will not be displayed, unless
this option is specified.

-I string, --ignore=string procedure name to be ignored. This option may
appear an unlimited number of times.

Some code has macros defined that confuse the lexical analysis. This will
cause them to be ignored. Other ways to cause functions to be ignored are:

Use K&R syntax for a procedure header.

Use a preprocessing macro to assemble the procedure header.

Simplify your code.
Generally speaking, anything you do that alters normal C syntax will
confuse the lexical analysis. If a procedure is not seen, then it will not
get counted. If code within a procedure is incomprehensible, you will
likely get inappropriate results.

-H, --no-header do not print scoring header. This option may not be preset
with environment variables or in initialization (rc) files.

If a script is going to process the scoring output, parsing is easier
without a header. The histogram output will always have a header.

-u unifdef-opt, --unifdef=unifdef-opt Run the source(s) through
unifdef(1BSD). This option may appear an unlimited number of times.

Strip out sections of code surrounded by #if/#endif directives. The option
argument is passed as an argument to the unifdef(1BSD) program. For
example:
complexity -u-Dsymbol
would cause symbol to be defined and remove sections of code preceded by
#ifndef symbol directives.

Please see the unifdef documentation for more information.

--unif-exe=prog Specify the unifdef program.

Alternate program to use for unifdef-ing the input.

-i file-name, --input=file-name file of file list.

Instead of either a command line list of input files or reading them from
standard input, read the list of files from this file.

--trace=file-name trace output file.

Print intermediate scores to a trace file.

-?, --help Display usage information and exit.

-!, --more-help Pass the extended usage information through a pager.

-> [cfgfile], --save-opts [=cfgfile] Save the option state to cfgfile. The
default is the last configuration file listed in the OPTION PRESETS
section, below. The command will exit after updating the config file.

-< cfgfile, --load-opts=cfgfile, --no-load-opts Load options from cfgfile.
The no-load-opts form will disable the loading of earlier config/rc/ini
files. --no-load-opts is handled early, out of order.

-v [{v|c|n --version [{v|c|n}]}] Output version of program and exit. The
default mode is ‘v’, a simple version. The ‘c’ mode will print copyright
information and ‘n’ will print the full copyright notice.

OPTION PRESETS

Any option that is not marked as not presettable may be preset by loading values from configuration ("RC" or ".INI") file(s) and values from environment variables named:
COMPLEXITY_<option-name> or COMPLEXITY
The environmental presets take precedence (are processed later than) the configuration files. The homerc files are "$@/complex.conf", "$HOME", "$PROJECT_ROOT/complex.conf", and ".". If any of these are directories, then the file .complexityrc is searched for within those directories.

ENVIRONMENT

See OPTION PRESETS for configuration environment variables.

FILES

See OPTION PRESETS for configuration files.

EXIT STATUS

One of the following exit values will be returned:
0 (EXIT_SUCCESS) Successful program execution.

1 (EXIT_FAILURE) The operation failed or the command syntax was not
valid.

3 (EXIT_NOMEM) insufficient memory to run program

4 (EXIT_HORRID_FUNCTION) One or more functions scored over 100

5 (EXIT_NO_DATA) No qualifying procedures were found.

6 (EXIT_ASSERT) Assertion failed

32 (EXIT_BAD_FILE) one or more input files were unreadable or empty.

66 (EX_NOINPUT) A specified configuration file could not be loaded.

70 (EX_SOFTWARE) libopts had an internal operational error. Please
report it to autogen-users@lists.sourceforge.net. Thank you.

AUTHORS

Bruce Korb

COPYRIGHT

Copyright (C) 2011-2020 Bruce Korb all rights reserved. This program is released under the terms of the GNU General Public License, version 3 or later.

BUGS

This program does not recognize K&R procedure headers.

Some procedures still get missed. Usually, these are procedures that use the C pre-processor to extend the C language in some way.

Initialized variable definitions within procedures have the initializing elements counted in the complexity calculation.

Please send bug reports to: bkorb@gnu.org

NOTES

This manual page was AutoGen-erated from the complexity option definitions.