CodeMatch vs copydetect

CodeMatch is a Windows program from SAFE Corporation for comparing source-code files across two directories, including their subdirectories. It ranks file pairs by correlation scores from 0 to 100, helping an examiner reduce many combinations to a smaller review list. Its hybrid methods compare statements, comments and strings, instruction sequences, and identifiers. Reports can show the material behind high correlations in detailed HTML, while a database export can produce an HTML summary. SAFE lists languages including C, C++, C#, Java, JavaScript, Python, SQL, Swift, Verilog, and VHDL, and says requested languages can usually be added within days. The maker also describes uses such as finding open-source code in proprietary software, assessing common authorship, and identifying shared algorithms. A press release allows no-charge comparison of up to 1 megabyte of source code. CodeMatch assists expert review rather than precisely identifying plagiarism. It is paid, with a free plan and trial, but no CodeMatch price is listed.

copydetect is a free tool for comparing code directories and producing an HTML report that highlights matching code slices. It uses Winnowing document fingerprinting, an approach also used by MOSS, and Pygments tokenization for the 500-plus languages Pygments can detect and tokenize. Users can compare test directories with reference directories such as previous submissions, and exclude boilerplate directories from matches. Noise, guarantee and display thresholds adjust what is detected and shown in reports. Install the package with pip; it requires Python 3.7 or later. The command-line tool recursively searches supplied directories, while its Python API supports comparisons and HTML report generation. Reports can be saved to a specified path, highlighted code can be truncated, and custom CSS can be linked. Configuration is available through command-line arguments or a JSON file. The package is MIT-licensed and classified for Education with Beta development status. Its documentation cautions that it may not catch plagiarism designed to evade detection and that a match does not establish that plagiarism occurred.