Similarity Percentage Computation

This project is derived from the software and text similarity tester SIM written by Dick Grune, Vrije Universiteit, Amsterdam.

SIM tests lexical similarity in natural language texts and in programs in

• C,
• C++,
• Java,
• Pascal,
• Modula-2,
• Miranda,
• Lisp,
• 8086 assembler code.

It can be used

• to detect duplicated code in large software projects, in program text, in shell scripts and in documentation;
• to detect plagiarism in (software) projects, educational and otherwise, and in scientific papers on the Web.

Similarities are reported

• in two parallel columns, with chunks of similar text side by side;
• in diff-format;
• in percentages.

Usage

You may execute make help to list all targets.

Build the Programs

If you are in a linux environment (not tested on other environment yet), to build all binaries, you may use:

make binaries

Install the Project

For the following command, you may set the DIR variable to customize the directory for installation. The default directory is /usr.

To install all files (including the completion files), you may use:

make install_all

To install binaries and manual only, you may use:

make install

Run the Programs

To see the similar part of several files, you may use:

sim_<language> <file1> <file2> ...

You may use | or / to separate the new files form the old files, for example:

sim_<language> <new_file1> <new_file2> ... | <old_file1> <old_file2> ...

To see the similarity percentage of several files, you may use:

sim_<language> -p <file1> <file2> ...

Some useful options includes:

• -s: Not show the similar part of the itself.
• -t N: Set the threshold (in percents) below which similarities will not be reported.
• -T: Suppresses the printing of information about the input files.
• -o <output>: Specify the output file.

License

Copyright (c) 1986, 2007, Dick Grune, Vrije Universiteit, The Netherlands All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

• Neither the name of the Vrije Universiteit nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.