diff --git a/Cargo.toml b/Cargo.toml
index 8c530db..ab751aa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -42,6 +42,7 @@ smallvec = {version = "1.6", features=["union"], optional = true}
 tokio = {version = "0.2", optional = true}
 
 [build-dependencies]
+cc = "1.0.68"
 rustc_version = "0.2"
 
 [dev-dependencies]
diff --git a/build.rs b/build.rs
index 6cb813f..2072ec2 100644
--- a/build.rs
+++ b/build.rs
@@ -1,8 +1,35 @@
 
 extern crate rustc_version;
+extern crate cc;
+
+use std::path::Path;
 
 use rustc_version::{version, version_meta, Channel};
 
+const FFI_SRC_DIR: &str = "src/ffi";
+
+fn build_cookie_wrapper(floc: impl AsRef<Path>)
+{
+    let mut builder = cc::Build::new();
+    // --std=c99 -W -Wall -Werror -pedantic -O3 -flto
+    builder.flag("--std=c11")
+	.flag("-W")
+	.flag("-Wall")
+	.flag_if_supported("-Wextra")
+	.flag("-Werror")
+	.flag("-pedantic")
+        .include("include/")
+	.opt_level(3)
+	.flag_if_supported("-flto")
+
+ 	// Not sure if we want these two. We can check the codegen later.
+	.pic(false)
+	.use_plt(false)
+	
+	.file(Path::new(FFI_SRC_DIR).join(floc))
+	.compile("cwrapper");
+}
+
 fn main() {
     // Assert we haven't travelled back in time
     assert!(version().unwrap().major >= 1);
@@ -22,4 +49,6 @@ fn main() {
             println!("cargo:rustc-cfg=dev");
         }
     }
+
+    build_cookie_wrapper("wrapper.c");
 }
diff --git a/include/cc20.h b/include/cc20.h
index 75be682..9484ac6 100644
--- a/include/cc20.h
+++ b/include/cc20.h
@@ -1,5 +1,7 @@
 #ifndef _CC20_H
 #define _CC20_H
+#include <stdint.h>
+#include <stddef.h>
 
 #define KEY_SIZE 32
 #define IV_SIZE 12
@@ -12,12 +14,12 @@ enum cc20_mode {
 typedef uint8_t cc20_key_t[KEY_SIZE];
 typedef uint8_t cc20_iv_t[IV_SIZE];
 
-struct cc20_metadata {
+typedef struct cc20_metadata {
 	FILE* backing;
 	cc20_key_t key;
 	cc20_iv_t iv;
 	enum cc20_mode mode;
-};
+} cc20_meta_t;
 
 typedef struct cc20_sink cc20_sink_t;
 
@@ -28,14 +30,19 @@ int cc20_gen_meta(FILE* file,
 		struct cc20_metadata* restrict output);
 
 cc20_sink_t* cc20_gen_sink(const struct cc20_metadata* meta);
+
 cc20_sink_t* cc20_gen_sink_full(FILE* file, 
 		const cc20_key_t* key,
 		const cc20_iv_t* iv,
 		enum cc20_mode mode);
-FILE* cc20_wrap(FILE* file, 
+
+FILE* cc20_wrap_full(FILE* file, 
 		const cc20_key_t* key,
 		const cc20_iv_t* iv,
 		enum cc20_mode mode);
+
+FILE* cc20_gen(const struct cc20_metadata* meta);
+
 int cc20_close_sink(cc20_sink_t* sink,
 		struct cc20_metadata* restrict meta);
 
diff --git a/src/ffi.rs b/src/ffi.rs
index f452987..e3bdcbc 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -53,6 +53,7 @@ pub enum CMode
 }
 
 mod interop;
+mod cookie;
 
 mod error;
 pub use error::*;
@@ -127,8 +128,18 @@ pub use error::*;
     };
     cc20_gen_sink(&meta as *const _)
 }
+
+#[no_mangle] pub unsafe extern "C" fn cc20_gen(meta: *const CPassthrough) -> *mut libc::FILE
+{
+    let sink = cc20_gen_sink(meta);
+    if sink.is_null() {
+	return ptr::null_mut();
+    }
+    cc20_wrap_sink(sink)
+}
+
 /// Create a wrapper `FILE*` that acts as a `Sink` when written to.
-#[no_mangle] pub unsafe extern "C" fn cc20_wrap(file: *mut libc::FILE, key: *const Key, iv: *const IV, mode: CMode) -> *mut libc::FILE
+#[no_mangle] pub unsafe extern "C" fn cc20_wrap_full(file: *mut libc::FILE, key: *const Key, iv: *const IV, mode: CMode) -> *mut libc::FILE
 {
     // No need to `no_unwind` this, nothing here can panic.
     let csink = cc20_gen_sink_full(file, key, iv, mode);
@@ -153,7 +164,8 @@ pub use error::*;
 /// Convert a `Sink` into a `FILE*`.
 #[no_mangle] pub unsafe extern "C" fn cc20_wrap_sink(sink: *mut CSink) -> *mut libc::FILE
 {
-    todo!("Create a Custom Stream in `wrapper.c` that allows creating a FILE* object from `sink`.")
+    //todo!("Create a Custom Stream in `wrapper.c` that allows creating a FILE* object from `sink`.")
+    cookie::create(sink)
 }
 
 impl Write for CPassthrough
diff --git a/src/ffi/cookie.rs b/src/ffi/cookie.rs
new file mode 100644
index 0000000..7e71d1f
--- /dev/null
+++ b/src/ffi/cookie.rs
@@ -0,0 +1,12 @@
+use super::*;
+use libc::{c_void, FILE};
+
+//FILE* _cc20c_create(cc20_sink_t* restrict sink)
+extern "C" {
+    fn _cc20c_create(sink: *mut c_void) -> *mut FILE;
+}
+
+#[inline(always)] pub unsafe fn create(raw_sink: *mut CSink) -> *mut FILE
+{
+    _cc20c_create(raw_sink as *mut c_void)
+}
diff --git a/src/ffi/wrapper.c b/src/ffi/wrapper.c
new file mode 100644
index 0000000..81f0699
--- /dev/null
+++ b/src/ffi/wrapper.c
@@ -0,0 +1,50 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <cc20.h>
+
+#define IGNORE(v) ((void)(v))
+
+static ssize_t cc20c_read(void* cookie, char* buffer, size_t size)
+{
+	IGNORE(cookie);
+	IGNORE(buffer);
+	IGNORE(size);
+
+	return -1;
+}
+
+static ssize_t cc20c_write(void* cookie, const char* buffer, size_t size)
+{
+	return cc20_write(buffer, 1, size, cookie);
+}
+
+static int cc20c_seek(void* cookie, off64_t* pos, int w)
+{
+	IGNORE(cookie);
+	IGNORE(pos);
+	IGNORE(w);
+
+	return -1;
+}
+
+static int cc20c_close(void* cookie)
+{
+	struct cc20_metadata meta;
+	cc20_close_sink(cookie, &meta);
+	if(meta.backing) fclose(meta.backing);
+	else return 1;
+	return 0;
+}
+
+FILE* _cc20c_create(cc20_sink_t* restrict sink)
+{
+	return fopencookie(sink, "wb", (cookie_io_functions_t){
+		.read =		&cc20c_read,
+		.write =	&cc20c_write,
+		.seek =		&cc20c_seek,
+		.close =	&cc20c_close,
+	});
+}