The Diff Match and Patch libraries offer robust algorithms to perform the operations required for synchronizing plain text.

1. Diff:
• Compare two blocks of plain text and efficiently return a list of differences.
• Diff Demo
2. Match:
• Given a search string, find its best fuzzy match in a block of plain text. Weighted for both accuracy and location.
• Match Demo
3. Patch:
• Apply a list of patches onto plain text. Use best-effort to apply patch even when the underlying text doesn't match.
• Patch Demo

Currently available in Java, JavaScript, Dart, C++, C#, Objective C, Lua and Python. Regardless of language, each library features the same API and the same functionality. All versions also have comprehensive test harnesses.

Algorithms

This library implements Myer's diff algorithm which is generally considered to be the best general-purpose diff. A layer of pre-diff speedups and post-diff cleanups surround the diff algorithm, improving both performance and output quality.

This library also implements a Bitap matching algorithm at the heart of a flexible matching and patching strategy.