commit 1d68ce12ed30691362fa39a4cf35aff910149377
Author: Peter J. Holzer <hjp@wsr.ac.at>
Date:   Sat Nov 11 17:23:34 2023 +0100

    Deduplicate files

diff --git a/dedup b/dedup
new file mode 100755
index 0000000..7946351
--- /dev/null
+++ b/dedup
@@ -0,0 +1,71 @@
+#!/usr/bin/python3
+
+from   hashlib import sha256
+from   os import walk, lstat, link, unlink
+from   os.path import join
+from   sys import argv, stderr
+
+def get_files():
+    result = []
+    for dir, subdirs, files in walk(argv[1]):
+        for f in files:
+            ff = join(dir, f)
+            s = lstat(ff)
+            result.append(
+                { "filename": ff,
+                  "mtime": s.st_mtime,
+                  "dev": s.st_dev,
+                  "ino": s.st_ino,
+                  "size": s.st_size,
+                })
+    result.sort(key=lambda x: x["mtime"])
+    return result
+
+def get_hash(filename):
+    hash = sha256()
+    with open(filename, "rb") as fh:
+        for chunk in iter(lambda: fh.read(0x10000), b""):
+            hash.update(chunk)
+    return hash.hexdigest()
+
+
+def dedup(files):
+    files_by_devino = {}
+    files_by_sizehash = {}
+
+    for file in files:
+        if (file["dev"], file["ino"]) in files_by_devino:
+            print("%s already seen (%d/%d), skipping" % (file["filename"], file["dev"], file["ino"]),
+                  file=stderr)
+            continue
+        try:
+            size = file["size"]
+            hash = None
+            if size in files_by_sizehash:
+                if None in files_by_sizehash[size]:
+                    hash = get_hash(files_by_sizehash[size][None]["filename"])
+                    files_by_sizehash[size][hash] = files_by_sizehash[size][None]
+                    del files_by_sizehash[size][None]
+
+                hash = get_hash(file["filename"])
+                if hash in files_by_sizehash[size] and file["dev"] == files_by_sizehash[size][hash]["dev"]:
+                    print("%s already seen (%s), replacing" % (file["filename"], hash),
+                          file=stderr)
+                    unlink(file["filename"])
+                    link(files_by_sizehash[size][hash]["filename"], file["filename"])
+                    continue
+            else:
+                files_by_sizehash[size] = {}
+            print("%s is new (%d/%d, %s)" % (file["filename"], file["dev"], file["ino"], hash),
+                  file=stderr)
+            files_by_devino[(file["dev"], file["ino"])] = file
+            files_by_sizehash[size][hash] = file
+        except EOFError:
+            print("%s is truncated, ignoring" % (file["filename"]),
+                  file=stderr)
+
+
+dedup(get_files())
+
+
+# vim: tw=99 sw=4 expandtab