zip recognize

lib/archive/archive.ml

@@ -0,0 +1,25 @@
+(** Base archive utitlities *)
+
+module Zip = Zip
+module Xz = Xz
+module Cpio = Cpio
+
+type t = { file : string; typ : string }
+
+let is_signature infile signature =
+  (* assume infile pos is 0 *)
+  let accumulator acc s =
+    match In_channel.input_char infile with
+    | None -> false
+    | Some c -> s == c && acc
+  in
+  Bytes.fold_left accumulator true signature
+
+(** matching common archive signatures *)
+let from file =
+  let infile = In_channel.open_bin file in
+  (* support for zip file for now *)
+  if is_signature infile Zip.signature then
+    Some { file = file; typ = "zip"; }
+  else
+    None

lib/archive/cpio.ml

@@ -0,0 +1 @@
+  let signature = Bytes.of_string "\x30\x37\x30\x37\x30\x37"

lib/archive/xz.ml

@@ -0,0 +1,2 @@
+(* this signature is the stream header signature *)
+let signature = Bytes.of_string "\xFD\x37\x7A\x58\x5A\x00"

lib/archive/zip.ml

@@ -10,5 +10,8 @@
     which has been deprecated or AES
     *)
 
-let signature = Bytes.of_string "PK\x00\x00"
+type t = { file : string; typ : string }
 
+let signature = Bytes.of_string "PK\x03\x04"
+
+let from file = { file = file; typ = "zip" }