# HG changeset patch
# User Steve Losh <steve@stevelosh.com>
# Date 1617928218 14400
# Node ID 4e5867a99afe1427c3ceb2228f06efc5de5b423b
# Parent  c5fc3602d0001a1088c131190d22010cbe410ac1
Sort package exports

diff -r c5fc3602d000 -r 4e5867a99afe make-docs.lisp
--- a/make-docs.lisp	Thu Apr 08 20:29:51 2021 -0400
+++ b/make-docs.lisp	Thu Apr 08 20:30:18 2021 -0400
@@ -22,6 +22,7 @@
         "LOSH.PRIORITY-QUEUES"
         "LOSH.QUEUES"
         "LOSH.RANDOM"
+        "LOSH.RING-BUFFERS"
         "LOSH.SEQUENCES"
         "LOSH.SHELL"
         "LOSH.WEIGHTLISTS"
diff -r c5fc3602d000 -r 4e5867a99afe package.lisp
--- a/package.lisp	Thu Apr 08 20:29:51 2021 -0400
+++ b/package.lisp	Thu Apr 08 20:30:18 2021 -0400
@@ -178,6 +178,29 @@
     :pq-ensure
     :pq-dequeue))
 
+(defpackage :losh.ring-buffers
+  (:use :cl :iterate :losh.quickutils
+    :losh.chili-dogs
+    :losh.eldritch-horrors
+    :losh.mutation)
+  (:documentation "Simple ring buffer implementation.")
+  (:export
+
+    :do-ring-buffer
+    :make-ring-buffer
+    :rb-contents
+    :rb-count
+    :rb-empty-p
+    :rb-full-p
+    :rb-pop
+    :rb-push
+    :rb-ref
+    :rb-safe-push
+    :rb-size
+    :ring-buffer
+
+    ))
+
 
 (defpackage :losh.control-flow
   (:use :cl :iterate :losh.quickutils
@@ -256,17 +279,20 @@
 
 (defpackage :losh.iterate
   (:use :cl :iterate :losh.quickutils
-    :losh.hash-sets)
+    :losh.hash-sets
+    :losh.ring-buffers)
   (:documentation "Custom `iterate` drivers and clauses.")
   (:export
 
     :across-flat-array
+    :against
     :anding
     :averaging
     :collect-frequencies
     :collect-hash
     :collect-set
     :cycling
+    :end
     :every-nth
     :finding-all
     :finding-first
@@ -274,31 +300,30 @@
     :in-array
     :in-hashset
     :in-lists
+    :in-ring-buffer
     :in-sequences
     :in-whatever
     :index-of-flat-array
     :initially
     :into
     :macroexpand-iterate
+    :matching
     :modulo
     :oring
+    :overlap
     :pairs-of-list
     :per-iteration-into
     :real-time
+    :returning
     :run-time
     :seed
     :since-start-into
     :skip-origin
+    :start
     :test
     :then
     :timing
     :within-radius
-    :returning
-    :matching
-    :against
-    :overlap
-    :start
-    :end
 
     ))
 
@@ -419,6 +444,7 @@
    :losh.priority-queues
    :losh.queues
    :losh.random
+   :losh.ring-buffers
    :losh.sequences
    :losh.shell
    :losh.weightlists
diff -r c5fc3602d000 -r 4e5867a99afe src/iterate.lisp
--- a/src/iterate.lisp	Thu Apr 08 20:29:51 2021 -0400
+++ b/src/iterate.lisp	Thu Apr 08 20:30:18 2021 -0400
@@ -730,6 +730,24 @@
     `(,kwd (,var) :in-hashtable (losh.hash-sets::hash-set-storage ,hset))))
 
 
+(defmacro-driver (FOR var IN-RING-BUFFER ring-buffer)
+  "Iterate over the elements of `ring-buffer`, oldest to newest."
+  (let ((kwd (if generate 'generate 'for)))
+    (with-gensyms (rb r w d s)
+      `(progn
+         (with ,rb = ,ring-buffer)
+         (with ,r = (losh.ring-buffers::r ,rb))
+         (with ,w = (losh.ring-buffers::w ,rb))
+         (with ,d = (losh.ring-buffers::data ,rb))
+         (with ,s = (losh.ring-buffers::size ,rb))
+         (,kwd ,var :next (if (= ,r ,w)
+                            (terminate)
+                            (prog1 (svref ,d ,r)
+                              (incf ,r)
+                              (when (= ,r ,s)
+                                (setf ,r 0)))))))))
+
+
 (defmacro-driver (FOR var SEED seed THEN then)
   "Bind `var` to `seed` initially, then to `then` on every iteration.