xdelta

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{{Infobox software

| name = xdelta

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| author = Joshua MacDonald

| developer = Joshua MacDonald

| released = {{Start date and age|1997|10|12}}

| discontinued =

| latest release version = {{wikidata|property|preferred|references|edit|P348|P548=Q2804309}} | latest release date = {{Start date and age|{{wikidata|qualifier|preferred|single|P348|P548=Q2804309|P577}}|df=yes}}

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| programming language = C and C++

| operating system = Unix-like, Microsoft Windows

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| genre = Utility software

| license = Apache License 2.0{{cite web |url=http://xdelta.org/2016/04/xdelta3-license-change.html |archive-url = https://web.archive.org/web/20240113231025/http://xdelta.org/2016/04/xdelta3-license-change.html |archive-date=2024-01-13 |url-status=usurped |title=Xdelta3 License Change |last=MacDonald |first=Joshua}}

| website = hide

}}

Xdelta{{Citation |last=MacDonald |first=Joshua |title=jmacd/xdelta |date=2025-01-01 |url=https://github.com/jmacd/xdelta |access-date=2025-01-03}} is a command line tool for delta encoding, which stores or transmits the difference (deltas) between sequential data, instead of entire files. This is similar to diff and patch, except diff computes and shows the difference between two complete files, while patch is primarily designed for human-readable text files; Xdelta is designed for binary files and does not generate human readable output.

Xdelta was first released sometime before October 12, 1997{{usurped|1=[https://web.archive.org/web/20240114103930/http://xdelta.org/2007/07/im-happy-about-e-mail-from-manager-at.html Mention of first version]}} by Joshua MacDonald, who currently maintains the program. The algorithm of xdelta1 was based on the algorithm of rsync, developed by Andrew Tridgell, though it uses a smaller block size.{{Citation needed|date=January 2025|reason=if the source of this information is already in this article, just replace this template with the citation to that source, but right now this just seems unverified at the end of a Paragraph}}

Xdelta version 3 is primarily designed to work with streams following the standardized VCDIFF format, and it realized the compatibility among other delta encoding software which supports the VCDIFF format.{{Citation needed|date=January 2025}} It runs on Unix-like operating systems and Microsoft Windows. xdelta can handle up to 2⁶⁴ byte files,[https://github.com/jmacd/xdelta/blob/wiki/TuningMemoryBudget.md xdelta3 memory tuning]{{Failed verification|date=January 2025|reason=the source given does not say anything about the max file size xdelta can handle (only the max input window size which seems to me to be Different), but it was likely on an older revision, either Way this isn't verifiable}} and it is suitable for large backups.