Add hash-backend and update README.

1 files changed, 51 insertions, 0 deletions

diff --git a/src/hash-backend.lisp b/src/hash-backend.lisp
new file mode 100644
index 0000000..91dc673
--- /dev/null
+++ b/src/hash-backend.lisp
@@ -0,0 +1,51 @@
+;; This file is part of eris-cl.
+;; Copyright (C) 2022 Piotr Szarmański
+
+;; eris-cl is free software: you can redistribute it and/or modify it under the
+;; terms of the GNU Lesser General Public License as published by the Free
+;; Software Foundation, either version 3 of the License, or (at your option) any
+;; later version.
+
+;; eris-cl is distributed in the hope that it will be useful, but WITHOUT ANY
+;; WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+;; A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License along with
+;; eris-cl. If not, see <https://www.gnu.org/licenses/>.
+
+(in-package :eris)
+
+(defclass hash-backend (encoding-backend decoding-backend)
+  ((table :type hash-table)))
+
+(defmethod shared-initialize :after ((hash-backend hash-backend) slot-names
+                                     &rest initargs
+                                     &key &allow-other-keys)
+  
+  (declare (ignore initargs slot-names))
+  (let ((hash-table (make-hash-table :test #'equalp)))
+    (with-slots (table output-function fetch-function) hash-backend
+      (setf table hash-table
+            fetch-function (lambda (reference)
+                             (declare (type octet-vector reference))
+                             (copy-seq (gethash reference hash-table)))
+            output-function (lambda (block reference)
+                              (declare (type octet-vector block reference))
+                              (setf (gethash reference hash-table)
+                                    block))))))
+
+(defmethod fetch-read-capability (read-capability (backend hash-backend) &key &allow-other-keys)
+  (declare (type read-capability read-capability))
+  (with-slots (fetch-function) backend
+    (eris-decode read-capability fetch-function :cache-capacity nil)))
+
+(defmethod store-data (input (backend hash-backend) &key (secret null-secret) (block-size 1kib) &allow-other-keys)
+  (declare (type octet-vector secret))
+  (with-slots (output-function) backend
+    (eris-encode input
+                 block-size
+                 output-function
+                 :hash-output nil
+                 :secret secret)))
+
+