Simplify octets-to-reference-pair

2 files changed, 11 insertions, 13 deletions

diff --git a/src/eris-decode.lisp b/src/eris-decode.lisp
index 43f8db0..b660cae 100644
--- a/src/eris-decode.lisp
+++ b/src/eris-decode.lisp
@@ -86,7 +86,7 @@ fetched from a trusted party.")
 
   (flet ((find-last-reference (block)
            (loop for i from (1- (/ block-size 64)) downto 0
-                 for key-reference = (octets-to-reference-pair (subseq-shared block (* 64 i)))
+                 for key-reference = (octets-to-reference-pair block (* 64 i))
                  unless (key-reference-null? key-reference)
                    return (values key-reference i))))
     (loop with position = 0
@@ -116,8 +116,8 @@ fetched from a trusted party.")
                  (when (zerop next-pos) ;; if 1+ mod blocks results in a zero, then update the next block
                    (process-block (cdr blocks) mod (1+ level)))
                  (let ((kr (octets-to-reference-pair
-                            (subseq-shared (data (cadr blocks))
-                                           (the fixnum (* next-pos 64))))))
+                            (data (cadr blocks))
+                            (the fixnum (* next-pos 64)))))
                    (setf (data current)
                          (funcall get-block (reference kr) (key kr) (svref nonce-array level)))))))
       (process-block (reverse root) (/ block-size 64) 0) ;; process the blocks from level 0 up
@@ -175,8 +175,8 @@ fetched from a trusted party.")
           until (eq nil (cdr blocks))
           when (or update-tree (not (eq block-position (pos lower-block))))
             do (let ((rk (octets-to-reference-pair
-                          (subseq-shared (data (car blocks))
-                                         (* 64 block-position)))))
+                          (data (car blocks))
+                          (* 64 block-position))))
                  (when (key-reference-null? rk)
                    (error 'eof :eof new-pos :position (pos stream)))
                  (setf (data lower-block) (funcall get-block (reference rk) (key rk) (svref nonce-array (1- level)))
@@ -221,7 +221,7 @@ cache."
            (root (funcall get-block (reference root-reference-pair) (key root-reference-pair) (make-nonce level))))
       ;; "Implementations MUST verify the key appearing in the read capability
       ;; if level of encoded content is larger than 0."
-      ;;(when (> level 0) (hash-check root (key root-reference-pair)))
+      (when (> level 0) (hash-check root (key root-reference-pair)))
       (case level
         ;; Treat level 0 blocks specially, since those are just a single buffer.
         (0 (let ((stream
diff --git a/src/eris.lisp b/src/eris.lisp
index c3bbe5f..b30c6a4 100644
--- a/src/eris.lisp
+++ b/src/eris.lisp
@@ -42,12 +42,10 @@
     (replace buf (reference pair) :start1 start)
     (replace buf (key pair) :start1 (+ 32 start)))
 
-(defun octets-to-reference-pair (octets)
-  (let ((key (make-array 32 :element-type '(unsigned-byte 8)))
-        (reference (make-array 32 :element-type '(unsigned-byte 8))))
-    (replace reference octets)
-    (replace key octets :start2 32)
-    (make-instance 'reference-pair :key key :reference reference)))
+(defun octets-to-reference-pair (octets &optional (start 0))
+  (declare (type (simple-array (unsigned-byte 8)) octets))
+  (make-instance 'reference-pair :key (subseq octets (+ 32 start) (+ 64 start))
+                                 :reference (subseq octets start (+ 32 start))))
 
 
 (defun compute-reference (block)
@@ -124,7 +122,7 @@
     (setf (level capability)
           (aref octets 1))
     (setf (reference-pair capability)
-          (octets-to-reference-pair (subseq-shared octets 2)))
+          (octets-to-reference-pair octets 2))
     capability))
 
 (defun read-capability-to-urn (capability)