1 files changed, 60 insertions, 0 deletions
diff --git a/lib/file_hash/init.nom b/lib/file_hash/init.nom
new file mode 100644
index 0000000..7b428cd
--- /dev/null
+++ b/lib/file_hash/init.nom
@@ -0,0 +1,60 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines some actions for hashing files and looking up files by hash.
+    
+use "filesystem"
+use "base64"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+lua> "local \$use_sha1, \$hashlib = pcall(require, 'openssl.digest')"
+test:
+    assume (hash "hello world") == (hash "hello world")
+    if ((hash "hello world") == (hash "goodbye")):
+        fail ("
+            Hash collision:
+                (hash "hello world") = \(hash "hello world")
+                (hash "goodbye") = \(hash "goodbye")
+        ")
+    
+    assume
+        (
+            hash ("
+                This is a really long string meant to stress test the hashing function and
+                ensure that it's not overflowing with long inputs.
+            ")
+        ) != "inf"
+    
+    if ((hash "\000") == (hash "\000\000\000\000\000")):
+        fail "Incorrect hashing of null strings"
+    
+    if $use_sha1:
+        assume ((hash "hello world") == "Kq5sNclPz7QV2+lfQIuc6R7oRu0=")
+
+if $use_sha1:
+    externally (hash $) means:
+        $hash = (=lua "\$hashlib.new('sha1'):final(\$)")
+        return (base64 $hash)
+..else:
+    # TODO: remove warning?
+    say ("
+        \027[31;1mWARNING: OpenSSL module not found. Defaulting to a non-cryptographically secure \
+        ..hash function.\027[0m
+    ")
+    
+    externally (hash $) means:
+        $bytes = ($, bytes)
+        $hash = ($bytes.1 << 7)
+        for $i in 2 to (size of $bytes):
+            $hash = ((1000003 * $hash) ~ $bytes.$i)
+        $hash = ($hash ~ (size of $bytes))
+        return "\$hash"
+
+externally (file with hash $hash) means:
+    for $filename in (files for "."):
+        $contents = (read file $filename)
+        $file_hash = (hash $contents)
+        if ($file_hash == $hash):
+            return $filename
+
+(hash of file $filename) parses as (hash (read file $filename))