From 5bbe75659aef55542268cbf35c66342cb22ce865 Mon Sep 17 00:00:00 2001
From: pacien
Date: Fri, 30 Nov 2018 18:44:20 +0100
Subject: isolate lzss chain module

---
 src/lzss/listpolyfill.nim | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 src/lzss/listpolyfill.nim

(limited to 'src/lzss/listpolyfill.nim')

diff --git a/src/lzss/listpolyfill.nim b/src/lzss/listpolyfill.nim
new file mode 100644
index 0000000..00b30ee
--- /dev/null
+++ b/src/lzss/listpolyfill.nim
@@ -0,0 +1,42 @@
+# gzip-like LZSS compressor
+# Copyright (C) 2018  Pacien TRAN-GIRARD
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import lists
+
+# https://github.com/nim-lang/Nim/pull/9805
+
+proc prepend*[T](L: var SinglyLinkedList[T], n: SinglyLinkedNode[T]) =
+  ## prepends a node to `L`. Efficiency: O(1).
+  n.next = L.head
+  L.head = n
+  if L.tail == nil: L.tail = n
+
+proc prepend*[T](L: var SinglyLinkedList[T], value: T) =
+  ## prepends a node to `L`. Efficiency: O(1).
+  listpolyfill.prepend(L, newSinglyLinkedNode(value))
+
+proc append*[T](L: var SinglyLinkedList[T], n: SinglyLinkedNode[T]) =
+  ## appends a node `n` to `L`. Efficiency: O(1).
+  n.next = nil
+  if L.tail != nil:
+    assert(L.tail.next == nil)
+    L.tail.next = n
+  L.tail = n
+  if L.head == nil: L.head = n
+
+proc append*[T](L: var SinglyLinkedList[T], value: T) =
+  ## appends a value to `L`. Efficiency: O(1).
+  append(L, newSinglyLinkedNode(value))
-- 
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