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+# open-vcdiff — VCDIFF (RFC 3284) encoder/decoder by Google.
+#
+# Generic-differencing format used by Chrome's SDCH (Shared Dictionary
+# Compression over HTTP), Google's Update protocol, and various delta
+# compression schemes. Apache-2.0.
+#
+# Upstream marked the repo archived on 2023-08-26 — no active
+# development but it's RFC-compliant and remains the canonical
+# reference C++ implementation. Worth packaging precisely because
+# nothing replaces it.
+
+distributable:
+  url: https://github.com/google/open-vcdiff/archive/refs/tags/{{version.tag}}.tar.gz
+  strip-components: 1
+
+versions:
+  # Upstream publishes git tags but ZERO GitHub Releases. Default
+  # `github: <repo>` mode queries /releases and returns empty
+  # (hence `not-found: version` on first CI runs). Force /tags.
+  github: google/open-vcdiff/tags
+  # Tag scheme changed: older releases used `open-vcdiff-X.Y` (dashes),
+  # recent ones use `openvcdiff-X.Y.Z` (no dash). Single combined regex.
+  strip: /^open-?vcdiff-/
+  # First tag `open-vcdiff-0.8` is 2-part — invalid strict semver.
+  ignore:
+    - /^open-vcdiff-0\.8$/
+
+platforms:
+  - linux/x86-64
+  - linux/aarch64
+  - darwin/x86-64
+  - darwin/aarch64
+
+build:
+  dependencies:
+    gnu.org/autoconf: '*'
+    gnu.org/automake: '*'
+    gnu.org/libtool: '*'
+    gnu.org/make: '*'
+    freedesktop.org/pkg-config: '*'
+    linux:
+      gnu.org/gcc: '*'
+  script:
+    # Upstream ships configure.ac only; run autoreconf to generate
+    # configure. Submodules (`gflags`, `gtest`) are NOT in the
+    # GitHub archive tarball — autoreconf's `aclocal` scans
+    # `gflags/m4` and bails with "no such file" without them.
+    # Create the empty directories so autoreconf proceeds; the
+    # actual gflags/gtest content is only needed for the test
+    # suite which we don't run.
+    - mkdir -p gflags/m4 gtest
+    - autoreconf -fi
+    - ./configure --prefix={{prefix}}
+    - make --jobs {{ hw.concurrency }}
+    - make install
+
+provides:
+  - bin/vcdiff
+
+test:
+  # Round-trip: create dict, target; encode; decode; check identity.
+  - run: |
+      printf 'the quick brown fox jumps over the lazy dog\n' > dict.txt
+      printf 'the quick brown FOX jumps over the lazy DOG\n' > target.txt
+      vcdiff encode -dictionary dict.txt -target target.txt -delta delta.vcdiff
+      vcdiff decode -dictionary dict.txt -delta delta.vcdiff -target out.txt
+      diff -q target.txt out.txt