1 files changed, 88 insertions, 0 deletions
diff --git a/lem/queue.lua b/lem/queue.lua
new file mode 100644
index 0000000..c3e5e42
--- /dev/null
+++ b/lem/queue.lua
@@ -0,0 +1,88 @@
+--
+-- This file is part of LEM, a Lua Event Machine.
+-- Copyright 2013 Emil Renner Berthing
+--
+-- LEM 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.
+--
+-- LEM 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 Lesser General Public License for more details.
+--
+-- You should have received a copy of the GNU Lesser General Public
+-- License along with LEM.  If not, see <http://www.gnu.org/licenses/>.
+--
+
+local utils = require 'lem.utils'
+
+local M = {}
+
+local Queue = {}
+Queue.__index = Queue
+M.Queue = Queue
+
+local remove = table.remove
+local thisthread, suspend, resume =
+	utils.thisthread, utils.suspend, utils.resume
+
+function Queue:put(v)
+	local n = self.n + 1
+	self.n = n
+
+	if n >= 1 then
+		self[n] = v
+	else
+		resume(remove(self, 1), v)
+	end
+end
+
+function Queue:signal(...)
+	local n = self.n
+	if n < 0 then
+		for i = 1, -n do
+			resume(self[i], ...)
+			self[i] = nil
+		end
+		self.n = 0
+	end
+end
+
+function Queue:get()
+	local n = self.n - 1
+	self.n = n
+
+	if n >= 0 then
+		return remove(self, 1)
+	end
+
+	self[-n] = thisthread()
+	return suspend()
+end
+
+function Queue:reset()
+	self:signal(nil, 'reset')
+	for i = self.n, 1, -1 do
+		self[i] = nil
+	end
+	self.n = 0
+end
+
+local get = Queue.get
+function Queue:consume()
+	return get, self
+end
+
+function Queue:empty()
+	return self.n <= 0
+end
+
+function M.new()
+	return setmetatable({ n = 0 }, Queue)
+end
+
+return M
+
+-- vim: ts=2 sw=2 noet: