diff --git a/ext/thread/extconf.rb b/ext/thread/extconf.rb
new file mode 100644
index 0000000..f2f0890
--- /dev/null
+++ b/ext/thread/extconf.rb
@@ -0,0 +1,3 @@
+require 'mkmf'
+
+create_makefile('thread')
diff --git a/ext/thread/thread.c b/ext/thread/thread.c
new file mode 100644
index 0000000..33365c1
--- /dev/null
+++ b/ext/thread/thread.c
@@ -0,0 +1,738 @@
+#include <ruby.h>
+
+RUBY_EXTERN size_t rb_objspace_data_type_memsize(VALUE);
+RUBY_EXTERN size_t rb_ary_memsize(VALUE);
+
+static VALUE
+rb_ary_buf_new(void)
+{
+    VALUE ary = rb_ary_tmp_new(1);
+    OBJ_UNTRUST(ary);
+    return ary;
+}
+
+static void
+wakeup_first_thread(VALUE list)
+{
+    VALUE thread;
+
+    while (!NIL_P(thread = rb_ary_shift(list))) {
+	if (RTEST(rb_thread_wakeup_alive(thread))) break;
+    }
+}
+
+static void
+wakeup_all_threads(VALUE list)
+{
+    VALUE thread, list0 = list;
+    long i;
+
+    list = rb_ary_subseq(list, 0, LONG_MAX);
+    rb_ary_clear(list0);
+    for (i = 0; i < RARRAY_LEN(list); ++i) {
+	thread = RARRAY_PTR(list)[i];
+	rb_thread_wakeup_alive(thread);
+    }
+    RB_GC_GUARD(list);
+}
+
+/*
+ *  Document-class: ConditionVariable
+ *
+ *  ConditionVariable objects augment class Mutex. Using condition variables,
+ *  it is possible to suspend while in the middle of a critical section until a
+ *  resource becomes available.
+ *
+ *  Example:
+ *
+ *    require 'thread'
+ *
+ *    mutex = Mutex.new
+ *    resource = ConditionVariable.new
+ *
+ *    a = Thread.new {
+ *	 mutex.synchronize {
+ *	   # Thread 'a' now needs the resource
+ *	   resource.wait(mutex)
+ *	   # 'a' can now have the resource
+ *	 }
+ *    }
+ *
+ *    b = Thread.new {
+ *	 mutex.synchronize {
+ *	   # Thread 'b' has finished using the resource
+ *	   resource.signal
+ *	 }
+ *    }
+ */
+
+typedef struct {
+    VALUE waiters;
+} CondVar;
+
+static void
+condvar_mark(void *ptr)
+{
+    CondVar *condvar = ptr;
+    rb_gc_mark(condvar->waiters);
+}
+
+#define condvar_free RUBY_TYPED_DEFAULT_FREE
+
+static size_t
+condvar_memsize(const void *ptr)
+{
+    size_t size = 0;
+    if (ptr) {
+	const CondVar *condvar = ptr;
+	size = sizeof(CondVar);
+	size += rb_ary_memsize(condvar->waiters);
+    }
+    return size;
+}
+
+static const rb_data_type_t condvar_data_type = {
+    "condvar",
+    {condvar_mark, condvar_free, condvar_memsize,},
+};
+
+#define GetCondVarPtr(obj, tobj) \
+    TypedData_Get_Struct(obj, CondVar, &condvar_data_type, tobj)
+
+static CondVar *
+get_condvar_ptr(VALUE self)
+{
+    CondVar *condvar;
+    GetCondVarPtr(self, condvar);
+    if (!condvar->waiters) {
+	rb_raise(rb_eArgError, "uninitialized CondionVariable");
+    }
+    return condvar;
+}
+
+static VALUE
+condvar_alloc(VALUE klass)
+{
+    CondVar *condvar;
+    return TypedData_Make_Struct(klass, CondVar, &condvar_data_type, condvar);
+}
+
+static void
+condvar_initialize(CondVar *condvar)
+{
+    condvar->waiters = rb_ary_buf_new();
+}
+
+/*
+ * Document-method: new
+ * call-seq: new
+ *
+ * Creates a new condvar.
+ */
+
+static VALUE
+rb_condvar_initialize(VALUE self)
+{
+    CondVar *condvar;
+    GetCondVarPtr(self, condvar);
+
+    condvar_initialize(condvar);
+
+    return self;
+}
+
+struct sleep_call {
+    int argc;
+    VALUE *argv;
+};
+
+static VALUE
+do_sleep(VALUE args)
+{
+    struct sleep_call *p = (struct sleep_call *)args;
+    return rb_funcall(p->argv[0], rb_intern("sleep"), p->argc-1, p->argv[1]);
+}
+
+static VALUE
+delete_current_thread(VALUE ary)
+{
+    return rb_ary_delete(ary, rb_thread_current());
+}
+
+/*
+ * Document-method: wait
+ * call-seq: wait(mutex, timeout=nil)
+ *
+ * Releases the lock held in +mutex+ and waits; reacquires the lock on wakeup.
+ *
+ * If +timeout+ is given, this method returns after +timeout+ seconds passed,
+ * even if no other thread doesn't signal.
+ */
+
+static VALUE
+rb_condvar_wait(int argc, VALUE *argv, VALUE self)
+{
+    VALUE waiters = get_condvar_ptr(self)->waiters;
+    struct sleep_call args;
+
+    args.argc = argc;
+    args.argv = argv;
+    rb_ary_push(waiters, rb_thread_current());
+    rb_ensure(do_sleep, (VALUE)&args, delete_current_thread, waiters);
+    return self;
+}
+
+/*
+ * Document-method: signal
+ * call-seq: signal
+ *
+ * Wakes up the first thread in line waiting for this lock.
+ */
+
+static VALUE
+rb_condvar_signal(VALUE self)
+{
+    wakeup_first_thread(get_condvar_ptr(self)->waiters);
+    return self;
+}
+
+/*
+ * Document-method: broadcast
+ * call-seq: broadcast
+ *
+ * Wakes up all threads waiting for this lock.
+ */
+
+static VALUE
+rb_condvar_broadcast(VALUE self)
+{
+    wakeup_all_threads(get_condvar_ptr(self)->waiters);
+    return self;
+}
+
+/*
+ *  Document-class: Queue
+ *
+ *  This class provides a way to synchronize communication between threads.
+ *
+ *  Example:
+ *
+ *    require 'thread'
+ *    queue = Queue.new
+ *
+ *  producer = Thread.new do
+ *    5.times do |i|
+ *	 sleep rand(i) # simulate expense
+ *	 queue << i
+ *	 puts "#{i} produced"
+ *    end
+ *  end
+ *
+ *  consumer = Thread.new do
+ *    5.times do |i|
+ *	 value = queue.pop
+ *	 sleep rand(i/2) # simulate expense
+ *	 puts "consumed #{value}"
+ *    end
+ *  end
+ *
+ */
+
+typedef struct {
+    VALUE que;
+    VALUE waiting;
+} Queue;
+
+static void
+queue_mark(void *ptr)
+{
+    Queue *queue = ptr;
+    rb_gc_mark(queue->que);
+    rb_gc_mark(queue->waiting);
+}
+
+#define queue_free RUBY_TYPED_DEFAULT_FREE
+
+static size_t
+queue_memsize(const void *ptr)
+{
+    size_t size = 0;
+    if (ptr) {
+	const Queue *queue = ptr;
+	size = sizeof(Queue);
+	size += rb_ary_memsize(queue->que);
+	size += rb_ary_memsize(queue->waiting);
+    }
+    return size;
+}
+
+static const rb_data_type_t queue_data_type = {
+    "queue",
+    {queue_mark, queue_free, queue_memsize,},
+};
+
+#define GetQueuePtr(obj, tobj) \
+    TypedData_Get_Struct(obj, Queue, &queue_data_type, tobj)
+
+static Queue *
+get_queue_ptr(VALUE self)
+{
+    Queue *queue;
+    GetQueuePtr(self, queue);
+    if (!queue->que || !queue->waiting) {
+	rb_raise(rb_eArgError, "uninitialized Queue");
+    }
+    return queue;
+}
+
+static VALUE
+queue_alloc(VALUE klass)
+{
+    Queue *queue;
+    return TypedData_Make_Struct(klass, Queue, &queue_data_type, queue);
+}
+
+static void
+queue_initialize(Queue *queue)
+{
+    queue->que = rb_ary_buf_new();
+    queue->waiting = rb_ary_buf_new();
+}
+
+/*
+ * Document-method: new
+ * call-seq: new
+ *
+ * Creates a new queue.
+ */
+
+static VALUE
+rb_queue_initialize(VALUE self)
+{
+    Queue *queue;
+    GetQueuePtr(self, queue);
+
+    queue_initialize(queue);
+
+    return self;
+}
+
+static VALUE
+queue_do_push(Queue *queue, VALUE obj)
+{
+    rb_ary_push(queue->que, obj);
+    wakeup_first_thread(queue->waiting);
+    return Qnil;
+}
+
+/*
+ * Document-method: push
+ * call-seq: push(obj)
+ *
+ * Pushes +obj+ to the queue.
+ */
+
+static VALUE
+rb_queue_push(VALUE self, VALUE obj)
+{
+    queue_do_push(get_queue_ptr(self), obj);
+    return self;
+}
+
+struct waiting_delete {
+    VALUE waiting;
+    VALUE th;
+};
+
+static VALUE
+queue_delete_from_waiting(struct waiting_delete *p)
+{
+    rb_ary_delete(p->waiting, p->th);
+    return Qnil;
+}
+
+static VALUE
+queue_do_pop(Queue *queue, VALUE should_block)
+{
+    struct waiting_delete args;
+
+    while (RARRAY_LEN(queue->que) == 0) {
+	if (!(int)should_block) {
+	    rb_raise(rb_eThreadError, "queue empty");
+	}
+	args.waiting = queue->waiting;
+	args.th	     = rb_thread_current();
+	rb_ary_push(args.waiting, args.th);
+	rb_ensure((VALUE (*)())rb_thread_sleep_forever, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
+    }
+
+    return rb_ary_shift(queue->que);
+}
+
+static int
+queue_pop_should_block(int argc, VALUE *argv)
+{
+    int should_block = 1;
+    switch (argc) {
+      case 0:
+	break;
+      case 1:
+	should_block = !RTEST(argv[0]);
+	break;
+      default:
+	rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
+    }
+    return should_block;
+}
+
+/*
+ * Document-method: pop
+ * call_seq: pop(non_block=false)
+ *
+ * Retrieves data from the queue.	If the queue is empty, the calling thread is
+ * suspended until data is pushed onto the queue.  If +non_block+ is true, the
+ * thread isn't suspended, and an exception is raised.
+ */
+
+static VALUE
+rb_queue_pop(int argc, VALUE *argv, VALUE self)
+{
+    Queue *queue = get_queue_ptr(self);
+    int should_block = queue_pop_should_block(argc, argv);
+    return queue_do_pop(queue, (VALUE)should_block);
+}
+
+static inline unsigned long
+queue_length(Queue *queue)
+{
+    return (unsigned long)RARRAY_LEN(queue->que);
+}
+
+static inline unsigned long
+queue_num_waiting(Queue *queue)
+{
+    return (unsigned long)RARRAY_LEN(queue->waiting);
+}
+
+/*
+ * Document-method: empty?
+ * call-seq: empty?
+ *
+ * Returns +true+ if the queue is empty.
+ */
+
+static VALUE
+rb_queue_empty_p(VALUE self)
+{
+    return queue_length(get_queue_ptr(self)) == 0 ? Qtrue : Qfalse;
+}
+
+/*
+ * Document-method: clear
+ * call-seq: clear
+ *
+ * Removes all objects from the queue.
+ */
+
+static VALUE
+rb_queue_clear(VALUE self)
+{
+    Queue *queue = get_queue_ptr(self);
+
+    rb_ary_clear(queue->que);
+
+    return self;
+}
+
+/*
+ * Document-method: length
+ * call-seq: length
+ *
+ * Returns the length of the queue.
+ */
+
+static VALUE
+rb_queue_length(VALUE self)
+{
+    unsigned long len = queue_length(get_queue_ptr(self));
+    return ULONG2NUM(len);
+}
+
+/*
+ * Document-method: num_waiting
+ * call-seq: num_waiting
+ *
+ * Returns the number of threads waiting on the queue.
+ */
+
+static VALUE
+rb_queue_num_waiting(VALUE self)
+{
+    long len = queue_num_waiting(get_queue_ptr(self));
+    return ULONG2NUM(len);
+}
+
+/*
+ *  Document-class: SizedQueue
+ *
+ * This class represents queues of specified size capacity.  The push operation
+ * may be blocked if the capacity is full.
+ *
+ * See Queue for an example of how a SizedQueue works.
+ */
+
+typedef struct  {
+    Queue queue_;
+    VALUE queue_wait;
+    unsigned long max;
+} SizedQueue;
+
+static void
+szqueue_mark(void *ptr)
+{
+    SizedQueue *szqueue = ptr;
+    queue_mark(&szqueue->queue_);
+    rb_gc_mark(szqueue->queue_wait);
+}
+
+#define szqueue_free queue_free
+
+static size_t
+szqueue_memsize(const void *ptr)
+{
+    size_t size = 0;
+    if (ptr) {
+	const SizedQueue *szqueue = ptr;
+	size = sizeof(SizedQueue) - sizeof(Queue);
+	size += queue_memsize(&szqueue->queue_);
+	size += rb_ary_memsize(szqueue->queue_wait);
+    }
+    return size;
+}
+
+static const rb_data_type_t szqueue_data_type = {
+    "sized_queue",
+    {szqueue_mark, szqueue_free, szqueue_memsize,},
+    &queue_data_type,
+};
+
+#define GetSizedQueuePtr(obj, tobj) \
+    TypedData_Get_Struct(obj, SizedQueue, &szqueue_data_type, tobj)
+
+static SizedQueue *
+get_szqueue_ptr(VALUE self)
+{
+    SizedQueue *szqueue;
+    GetSizedQueuePtr(self, szqueue);
+    if (!szqueue->queue_.que || !szqueue->queue_.waiting || !szqueue->queue_wait) {
+	rb_raise(rb_eArgError, "uninitialized Queue");
+    }
+    return szqueue;
+}
+
+static VALUE
+szqueue_alloc(VALUE klass)
+{
+    SizedQueue *szqueue;
+    return TypedData_Make_Struct(klass, SizedQueue, &szqueue_data_type, szqueue);
+}
+
+/*
+ * Document-method: new
+ * call-seq: new(max)
+ *
+ * Creates a fixed-length queue with a maximum size of +max+.
+ */
+
+static VALUE
+rb_szqueue_initialize(VALUE self, VALUE vmax)
+{
+    long max;
+    SizedQueue *szqueue;
+    GetSizedQueuePtr(self, szqueue);
+
+    max = NUM2LONG(vmax);
+    if (max <= 0) {
+	rb_raise(rb_eArgError, "queue size must be positive");
+    }
+    queue_initialize(&szqueue->queue_);
+    szqueue->queue_wait = rb_ary_buf_new();
+    szqueue->max = (unsigned long)max;
+
+    return self;
+}
+
+/*
+ * Document-method: max
+ * call-seq: max
+ *
+ * Returns the maximum size of the queue.
+ */
+
+static VALUE
+rb_szqueue_max_get(VALUE self)
+{
+    unsigned long max = get_szqueue_ptr(self)->max;
+    return ULONG2NUM(max);
+}
+
+/*
+ * Document-method: max=
+ * call-seq: max=(n)
+ *
+ * Sets the maximum size of the queue.
+ */
+
+static VALUE
+rb_szqueue_max_set(VALUE self, VALUE vmax)
+{
+    SizedQueue *szqueue = get_szqueue_ptr(self);
+    long max = NUM2LONG(vmax), diff = 0;
+    VALUE t;
+
+    if (max <= 0) {
+	rb_raise(rb_eArgError, "queue size must be positive");
+    }
+    if ((unsigned long)max > szqueue->max) {
+	diff = max - szqueue->max;
+    }
+    szqueue->max = max;
+    while (diff > 0 && !NIL_P(t = rb_ary_shift(szqueue->queue_wait))) {
+	rb_thread_wakeup_alive(t);
+    }
+    return vmax;
+}
+
+static VALUE
+szqueue_do_push(SizedQueue *szqueue, VALUE obj)
+{
+    struct waiting_delete args;
+    VALUE thread;
+
+    while (queue_length(&szqueue->queue_) >= szqueue->max) {
+	args.waiting = szqueue->queue_wait;
+	args.th      = rb_thread_current();
+	rb_ary_push(args.waiting, args.th);
+	rb_ensure((VALUE (*)())rb_thread_sleep_forever, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
+    }
+    return queue_do_push(&szqueue->queue_, obj);
+}
+
+/*
+ * Document-method: push
+ * call-seq: push(obj)
+ *
+ * Pushes +obj+ to the queue.  If there is no space left in the queue, waits
+ * until space becomes available.
+ */
+
+static VALUE
+rb_szqueue_push(VALUE self, VALUE obj)
+{
+    szqueue_do_push(get_szqueue_ptr(self), obj);
+    return self;
+}
+
+static VALUE
+szqueue_do_pop(SizedQueue *szqueue, VALUE should_block)
+{
+    VALUE retval = queue_do_pop(&szqueue->queue_, should_block);
+
+    if (queue_length(&szqueue->queue_) < szqueue->max) {
+	wakeup_first_thread(szqueue->queue_wait);
+    }
+
+    return retval;
+}
+
+/*
+ * Document-method: pop
+ * call_seq: pop(non_block=false)
+ *
+ * Returns the number of threads waiting on the queue.
+ */
+
+static VALUE
+rb_szqueue_pop(int argc, VALUE *argv, VALUE self)
+{
+    SizedQueue *szqueue = get_szqueue_ptr(self);
+    int should_block = queue_pop_should_block(argc, argv);
+    return szqueue_do_pop(szqueue, (VALUE)should_block);
+}
+
+/*
+ * Document-method: pop
+ * call_seq: pop(non_block=false)
+ *
+ * Returns the number of threads waiting on the queue.
+ */
+
+static VALUE
+rb_szqueue_num_waiting(VALUE self)
+{
+    SizedQueue *szqueue = get_szqueue_ptr(self);
+    long len = queue_num_waiting(&szqueue->queue_);
+    len += RARRAY_LEN(szqueue->queue_wait);
+    return ULONG2NUM(len);
+}
+
+#ifndef UNDER_THREAD
+#define UNDER_THREAD 1
+#endif
+
+void
+Init_thread(void)
+{
+#if UNDER_THREAD
+#define DEFINE_CLASS_UNDER_THREAD(name, super) rb_define_class_under(rb_cThread, #name, super)
+#define ALIAS_GLOBCAL_CONST(name) do {		      \
+	ID id = rb_intern_const(#name);		      \
+	if (!rb_const_defined_at(rb_cObject, id)) {     \
+	    rb_const_set(rb_cObject, id, rb_c##name);   \
+	}						      \
+    } while (0)
+#else
+#define DEFINE_CLASS_UNDER_THREAD(name, super) rb_define_class(name, super)
+#define ALIAS_GLOBCAL_CONST(name) do { /* nothing */ } while (0)
+#endif
+    VALUE rb_cConditionVariable = DEFINE_CLASS_UNDER_THREAD(ConditionVariable, rb_cObject);
+    VALUE rb_cQueue = DEFINE_CLASS_UNDER_THREAD(Queue, rb_cObject);
+    VALUE rb_cSizedQueue = DEFINE_CLASS_UNDER_THREAD(SizedQueue, rb_cQueue);
+
+    rb_define_alloc_func(rb_cConditionVariable, condvar_alloc);
+    rb_define_method(rb_cConditionVariable, "initialize", rb_condvar_initialize, 0);
+    rb_define_method(rb_cConditionVariable, "wait", rb_condvar_wait, -1);
+    rb_define_method(rb_cConditionVariable, "signal", rb_condvar_signal, 0);
+    rb_define_method(rb_cConditionVariable, "broadcast", rb_condvar_broadcast, 0);
+
+    rb_define_alloc_func(rb_cQueue, queue_alloc);
+    rb_define_method(rb_cQueue, "initialize", rb_queue_initialize, 0);
+    rb_define_method(rb_cQueue, "push", rb_queue_push, 1);
+    rb_define_method(rb_cQueue, "pop", rb_queue_pop, -1);
+    rb_define_method(rb_cQueue, "empty?", rb_queue_empty_p, 0);
+    rb_define_method(rb_cQueue, "clear", rb_queue_clear, 0);
+    rb_define_method(rb_cQueue, "length", rb_queue_length, 0);
+    rb_define_method(rb_cQueue, "num_waiting", rb_queue_num_waiting, 0);
+    rb_alias(rb_cQueue, rb_intern("enq"), rb_intern("push"));
+    rb_alias(rb_cQueue, rb_intern("<<"), rb_intern("push"));
+    rb_alias(rb_cQueue, rb_intern("deq"), rb_intern("pop"));
+    rb_alias(rb_cQueue, rb_intern("shift"), rb_intern("pop"));
+    rb_alias(rb_cQueue, rb_intern("size"), rb_intern("length"));
+
+    rb_define_alloc_func(rb_cSizedQueue, szqueue_alloc);
+    rb_define_method(rb_cSizedQueue, "initialize", rb_szqueue_initialize, 1);
+    rb_define_method(rb_cSizedQueue, "max", rb_szqueue_max_get, 0);
+    rb_define_method(rb_cSizedQueue, "max=", rb_szqueue_max_set, 1);
+    rb_define_method(rb_cSizedQueue, "push", rb_szqueue_push, 1);
+    rb_define_method(rb_cSizedQueue, "pop", rb_szqueue_pop, -1);
+    rb_define_method(rb_cSizedQueue, "num_waiting", rb_szqueue_num_waiting, 0);
+    rb_alias(rb_cSizedQueue, rb_intern("enq"), rb_intern("push"));
+    rb_alias(rb_cSizedQueue, rb_intern("<<"), rb_intern("push"));
+    rb_alias(rb_cSizedQueue, rb_intern("deq"), rb_intern("pop"));
+    rb_alias(rb_cSizedQueue, rb_intern("shift"), rb_intern("pop"));
+
+    rb_provide("thread.rb");
+    ALIAS_GLOBCAL_CONST(ConditionVariable);
+    ALIAS_GLOBCAL_CONST(Queue);
+    ALIAS_GLOBCAL_CONST(SizedQueue);
+}
diff --git a/lib/thread.rb b/lib/thread.rb
deleted file mode 100644
index 0bc95a2..0000000
--- a/lib/thread.rb
+++ /dev/null
@@ -1,366 +0,0 @@
-#
-#               thread.rb - thread support classes
-#                       by Yukihiro Matsumoto <matz@netlab.co.jp>
-#
-# Copyright (C) 2001  Yukihiro Matsumoto
-# Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
-# Copyright (C) 2000  Information-technology Promotion Agency, Japan
-#
-
-unless defined? Thread
-  raise "Thread not available for this ruby interpreter"
-end
-
-unless defined? ThreadError
-  class ThreadError < StandardError
-  end
-end
-
-if $DEBUG
-  Thread.abort_on_exception = true
-end
-
-#
-# ConditionVariable objects augment class Mutex. Using condition variables,
-# it is possible to suspend while in the middle of a critical section until a
-# resource becomes available.
-#
-# Example:
-#
-#   require 'thread'
-#
-#   mutex = Mutex.new
-#   resource = ConditionVariable.new
-#
-#   a = Thread.new {
-#     mutex.synchronize {
-#       # Thread 'a' now needs the resource
-#       resource.wait(mutex)
-#       # 'a' can now have the resource
-#     }
-#   }
-#
-#   b = Thread.new {
-#     mutex.synchronize {
-#       # Thread 'b' has finished using the resource
-#       resource.signal
-#     }
-#   }
-#
-class ConditionVariable
-  #
-  # Creates a new ConditionVariable
-  #
-  def initialize
-    @waiters = {}
-    @waiters_mutex = Mutex.new
-  end
-
-  #
-  # Releases the lock held in +mutex+ and waits; reacquires the lock on wakeup.
-  #
-  # If +timeout+ is given, this method returns after +timeout+ seconds passed,
-  # even if no other thread doesn't signal.
-  #
-  def wait(mutex, timeout=nil)
-    Thread.handle_interrupt(StandardError => :never) do
-      begin
-        Thread.handle_interrupt(StandardError => :on_blocking) do
-          @waiters_mutex.synchronize do
-            @waiters[Thread.current] = true
-          end
-          mutex.sleep timeout
-        end
-      ensure
-        @waiters_mutex.synchronize do
-          @waiters.delete(Thread.current)
-        end
-      end
-    end
-    self
-  end
-
-  #
-  # Wakes up the first thread in line waiting for this lock.
-  #
-  def signal
-    Thread.handle_interrupt(StandardError => :on_blocking) do
-      begin
-        t, _ = @waiters_mutex.synchronize { @waiters.shift }
-        t.run if t
-      rescue ThreadError
-        retry # t was already dead?
-      end
-    end
-    self
-  end
-
-  #
-  # Wakes up all threads waiting for this lock.
-  #
-  def broadcast
-    Thread.handle_interrupt(StandardError => :on_blocking) do
-      threads = nil
-      @waiters_mutex.synchronize do
-        threads = @waiters.keys
-        @waiters.clear
-      end
-      for t in threads
-        begin
-          t.run
-        rescue ThreadError
-        end
-      end
-    end
-    self
-  end
-end
-
-#
-# This class provides a way to synchronize communication between threads.
-#
-# Example:
-#
-#   require 'thread'
-#
-#   queue = Queue.new
-#
-#   producer = Thread.new do
-#     5.times do |i|
-#       sleep rand(i) # simulate expense
-#       queue << i
-#       puts "#{i} produced"
-#     end
-#   end
-#
-#   consumer = Thread.new do
-#     5.times do |i|
-#       value = queue.pop
-#       sleep rand(i/2) # simulate expense
-#       puts "consumed #{value}"
-#     end
-#   end
-#
-#   consumer.join
-#
-class Queue
-  #
-  # Creates a new queue.
-  #
-  def initialize
-    @que = []
-    @que.taint          # enable tainted communication
-    @num_waiting = 0
-    self.taint
-    @mutex = Mutex.new
-    @cond = ConditionVariable.new
-  end
-
-  #
-  # Pushes +obj+ to the queue.
-  #
-  def push(obj)
-    Thread.handle_interrupt(StandardError => :on_blocking) do
-      @mutex.synchronize do
-        @que.push obj
-        @cond.signal
-      end
-      self
-    end
-  end
-
-  #
-  # Alias of push
-  #
-  alias << push
-
-  #
-  # Alias of push
-  #
-  alias enq push
-
-  #
-  # Retrieves data from the queue.  If the queue is empty, the calling thread is
-  # suspended until data is pushed onto the queue.  If +non_block+ is true, the
-  # thread isn't suspended, and an exception is raised.
-  #
-  def pop(non_block=false)
-    Thread.handle_interrupt(StandardError => :on_blocking) do
-      @mutex.synchronize do
-        while true
-          if @que.empty?
-            if non_block
-              raise ThreadError, "queue empty"
-            else
-              begin
-                @num_waiting += 1
-                @cond.wait @mutex
-              ensure
-                @num_waiting -= 1
-              end
-            end
-          else
-            return @que.shift
-          end
-        end
-      end
-    end
-  end
-
-  #
-  # Alias of pop
-  #
-  alias shift pop
-
-  #
-  # Alias of pop
-  #
-  alias deq pop
-
-  #
-  # Returns +true+ if the queue is empty.
-  #
-  def empty?
-    @que.empty?
-  end
-
-  #
-  # Removes all objects from the queue.
-  #
-  def clear
-    @que.clear
-    self
-  end
-
-  #
-  # Returns the length of the queue.
-  #
-  def length
-    @que.length
-  end
-
-  #
-  # Alias of length.
-  #
-  alias size length
-
-  #
-  # Returns the number of threads waiting on the queue.
-  #
-  def num_waiting
-    @num_waiting
-  end
-end
-
-#
-# This class represents queues of specified size capacity.  The push operation
-# may be blocked if the capacity is full.
-#
-# See Queue for an example of how a SizedQueue works.
-#
-class SizedQueue < Queue
-  #
-  # Creates a fixed-length queue with a maximum size of +max+.
-  #
-  def initialize(max)
-    raise ArgumentError, "queue size must be positive" unless max > 0
-    @max = max
-    @enque_cond = ConditionVariable.new
-    @num_enqueue_waiting = 0
-    super()
-  end
-
-  #
-  # Returns the maximum size of the queue.
-  #
-  def max
-    @max
-  end
-
-  #
-  # Sets the maximum size of the queue.
-  #
-  def max=(max)
-    raise ArgumentError, "queue size must be positive" unless max > 0
-
-    @mutex.synchronize do
-      if max <= @max
-        @max = max
-      else
-        diff = max - @max
-        @max = max
-        diff.times do
-          @enque_cond.signal
-        end
-      end
-    end
-    max
-  end
-
-  #
-  # Pushes +obj+ to the queue.  If there is no space left in the queue, waits
-  # until space becomes available.
-  #
-  def push(obj)
-    Thread.handle_interrupt(RuntimeError => :on_blocking) do
-      @mutex.synchronize do
-        while true
-          break if @que.length < @max
-          @num_enqueue_waiting += 1
-          begin
-            @enque_cond.wait @mutex
-          ensure
-            @num_enqueue_waiting -= 1
-          end
-        end
-
-        @que.push obj
-        @cond.signal
-      end
-      self
-    end
-  end
-
-  #
-  # Alias of push
-  #
-  alias << push
-
-  #
-  # Alias of push
-  #
-  alias enq push
-
-  #
-  # Retrieves data from the queue and runs a waiting thread, if any.
-  #
-  def pop(*args)
-    retval = super
-    @mutex.synchronize do
-      if @que.length < @max
-        @enque_cond.signal
-      end
-    end
-    retval
-  end
-
-  #
-  # Alias of pop
-  #
-  alias shift pop
-
-  #
-  # Alias of pop
-  #
-  alias deq pop
-
-  #
-  # Returns the number of threads waiting on the queue.
-  #
-  def num_waiting
-    @num_waiting + @num_enqueue_waiting
-  end
-end
-
-# Documentation comments:
-#  - How do you make RDoc inherit documentation from superclass?