# sisong/HDiffPatch

a C\C++ library and command-line tools for Diff & Patch between binary files or directories(folder); cross-platform; runs fast; create small delta/differential; support large files and limit memory requires when diff & patch.

Repository: https://github.com/sisong/HDiffPatch
Canonical: https://ross.abutalabs.com/products/hdiffpatch
Language: C++
License: NOASSERTION
License Family: other
Topics: diff, patch, bsdiff, update, delta, xdelta, patcher, hdiffpatch, differential, binary, directories, dir, folder, android, delta-compression, vcdiff, open-vcdiff
Last push: 2026-07-31T05:56:50+00:00

## Health v2 (maintenance only)
Score: 96/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 95, release rhythm 95, longevity 100
- inputs: {"age_days": 5000, "days_push": 33, "days_rel": 33, "gap_med": 20, "n_releases_24m": 10}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2082, forks 348 (observed 2026-08-28T04:06:11.725460+00:00)

## What it is
HDiffPatch is a C/C++ library and command-line tools for creating and applying binary diffs (deltas) between files or directories. It produces small patch files quickly with bounded memory usage and is compatible with bsdiff and VCDIFF (xdelta3/open-vcdiff) formats.

## Use cases
- create small delta patches between binary file versions
- apply patches to update files or directories
- generate OTA update packages for embedded devices
- diff and patch Android APKs or zip archives
- sync files when old versions are unavailable using hash certificates
- limit memory usage when diffing very large files

## When to choose
- you need fast, memory-efficient binary or directory diffing
- you want small delta files for software updates or OTA distribution
- you need bsdiff or VCDIFF format compatibility
- you target embedded or low-RAM devices for patching

## When to avoid
- you only need text diffs for source code (use git diff)
- you need a pure managed-language solution without C/C++ integration
- you require app-store-compatible APK patching without re-signing (use sfpatcher instead)

## Facets
- artifact type: library
- maturity: stable
- function: compression, cli, developer-tools
- domain: files, developer-tools, cross-platform
- platform: cross-platform, cli, windows, embedded
- tags: binary-diff, delta-compression, patching, ota-updates, bsdiff, vcdiff, directory-diff, android, linux, macos

## Member repositories
- sisong/HDiffPatch (main) score 96

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:11.725460+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:55:56.039101+00:00, confidence not recorded.
  - readme: https://github.com/sisong/HDiffPatch (fetched 2026-08-28T04:06:11.725460+00:00, sha b0f61261d198)
- Data as of 2026-08-30T08:39:29.467469+00:00.