Initial commit

7 files changed, 929 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.o
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..1263948
--- /dev/null
+++ b/Makefile
@@ -0,0 +1 @@
+all:
diff --git a/README.asciidoc b/README.asciidoc
new file mode 100644
index 0000000..fdea59e
--- /dev/null
+++ b/README.asciidoc
@@ -0,0 +1,9 @@
+= NIF helpers
+
+An Erlang.mk plugin and C library for writing NIFs.
+
+== Getting help
+
+* Official IRC Channel: #ninenines on irc.freenode.net
+* https://github.com/ninenines/nif_helpers/issues[Issues tracker]
+* http://ninenines.eu/services[Commercial Support]
diff --git a/compat/sys/queue.h b/compat/sys/queue.h
new file mode 100644
index 0000000..daf4553
--- /dev/null
+++ b/compat/sys/queue.h
@@ -0,0 +1,574 @@
+/*
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)queue.h	8.5 (Berkeley) 8/20/94
+ */
+
+#ifndef	_SYS_QUEUE_H_
+#define	_SYS_QUEUE_H_
+
+/*
+ * This file defines five types of data structures: singly-linked lists,
+ * lists, simple queues, tail queues, and circular queues.
+ *
+ * A singly-linked list is headed by a single forward pointer. The
+ * elements are singly linked for minimum space and pointer manipulation
+ * overhead at the expense of O(n) removal for arbitrary elements. New
+ * elements can be added to the list after an existing element or at the
+ * head of the list.  Elements being removed from the head of the list
+ * should use the explicit macro for this purpose for optimum
+ * efficiency. A singly-linked list may only be traversed in the forward
+ * direction.  Singly-linked lists are ideal for applications with large
+ * datasets and few or no removals or for implementing a LIFO queue.
+ *
+ * A list is headed by a single forward pointer (or an array of forward
+ * pointers for a hash table header). The elements are doubly linked
+ * so that an arbitrary element can be removed without a need to
+ * traverse the list. New elements can be added to the list before
+ * or after an existing element or at the head of the list. A list
+ * may only be traversed in the forward direction.
+ *
+ * A simple queue is headed by a pair of pointers, one the head of the
+ * list and the other to the tail of the list. The elements are singly
+ * linked to save space, so elements can only be removed from the
+ * head of the list. New elements can be added to the list after
+ * an existing element, at the head of the list, or at the end of the
+ * list. A simple queue may only be traversed in the forward direction.
+ *
+ * A tail queue is headed by a pair of pointers, one to the head of the
+ * list and the other to the tail of the list. The elements are doubly
+ * linked so that an arbitrary element can be removed without a need to
+ * traverse the list. New elements can be added to the list before or
+ * after an existing element, at the head of the list, or at the end of
+ * the list. A tail queue may be traversed in either direction.
+ *
+ * A circle queue is headed by a pair of pointers, one to the head of the
+ * list and the other to the tail of the list. The elements are doubly
+ * linked so that an arbitrary element can be removed without a need to
+ * traverse the list. New elements can be added to the list before or after
+ * an existing element, at the head of the list, or at the end of the list.
+ * A circle queue may be traversed in either direction, but has a more
+ * complex end of list detection.
+ *
+ * For details on the use of these macros, see the queue(3) manual page.
+ */
+
+/*
+ * List definitions.
+ */
+#define	LIST_HEAD(name, type)						\
+struct name {								\
+	struct type *lh_first;	/* first element */			\
+}
+
+#define	LIST_HEAD_INITIALIZER(head)					\
+	{ NULL }
+
+#define	LIST_ENTRY(type)						\
+struct {								\
+	struct type *le_next;	/* next element */			\
+	struct type **le_prev;	/* address of previous next element */	\
+}
+
+/*
+ * List functions.
+ */
+#define	LIST_INIT(head) do {						\
+	(head)->lh_first = NULL;					\
+} while (/*CONSTCOND*/0)
+
+#define	LIST_INSERT_AFTER(listelm, elm, field) do {			\
+	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)	\
+		(listelm)->field.le_next->field.le_prev =		\
+		    &(elm)->field.le_next;				\
+	(listelm)->field.le_next = (elm);				\
+	(elm)->field.le_prev = &(listelm)->field.le_next;		\
+} while (/*CONSTCOND*/0)
+
+#define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
+	(elm)->field.le_prev = (listelm)->field.le_prev;		\
+	(elm)->field.le_next = (listelm);				\
+	*(listelm)->field.le_prev = (elm);				\
+	(listelm)->field.le_prev = &(elm)->field.le_next;		\
+} while (/*CONSTCOND*/0)
+
+#define	LIST_INSERT_HEAD(head, elm, field) do {				\
+	if (((elm)->field.le_next = (head)->lh_first) != NULL)		\
+		(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
+	(head)->lh_first = (elm);					\
+	(elm)->field.le_prev = &(head)->lh_first;			\
+} while (/*CONSTCOND*/0)
+
+#define	LIST_REMOVE(elm, field) do {					\
+	if ((elm)->field.le_next != NULL)				\
+		(elm)->field.le_next->field.le_prev = 			\
+		    (elm)->field.le_prev;				\
+	*(elm)->field.le_prev = (elm)->field.le_next;			\
+} while (/*CONSTCOND*/0)
+
+#define	LIST_FOREACH(var, head, field)					\
+	for ((var) = ((head)->lh_first);				\
+		(var);							\
+		(var) = ((var)->field.le_next))
+
+/*
+ * List access methods.
+ */
+#define	LIST_EMPTY(head)		((head)->lh_first == NULL)
+#define	LIST_FIRST(head)		((head)->lh_first)
+#define	LIST_NEXT(elm, field)		((elm)->field.le_next)
+
+
+/*
+ * Singly-linked List definitions.
+ */
+#define	SLIST_HEAD(name, type)						\
+struct name {								\
+	struct type *slh_first;	/* first element */			\
+}
+
+#define	SLIST_HEAD_INITIALIZER(head)					\
+	{ NULL }
+
+#define	SLIST_ENTRY(type)						\
+struct {								\
+	struct type *sle_next;	/* next element */			\
+}
+
+/*
+ * Singly-linked List functions.
+ */
+#define	SLIST_INIT(head) do {						\
+	(head)->slh_first = NULL;					\
+} while (/*CONSTCOND*/0)
+
+#define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
+	(elm)->field.sle_next = (slistelm)->field.sle_next;		\
+	(slistelm)->field.sle_next = (elm);				\
+} while (/*CONSTCOND*/0)
+
+#define	SLIST_INSERT_HEAD(head, elm, field) do {			\
+	(elm)->field.sle_next = (head)->slh_first;			\
+	(head)->slh_first = (elm);					\
+} while (/*CONSTCOND*/0)
+
+#define	SLIST_REMOVE_HEAD(head, field) do {				\
+	(head)->slh_first = (head)->slh_first->field.sle_next;		\
+} while (/*CONSTCOND*/0)
+
+#define	SLIST_REMOVE(head, elm, type, field) do {			\
+	if ((head)->slh_first == (elm)) {				\
+		SLIST_REMOVE_HEAD((head), field);			\
+	}								\
+	else {								\
+		struct type *curelm = (head)->slh_first;		\
+		while(curelm->field.sle_next != (elm))			\
+			curelm = curelm->field.sle_next;		\
+		curelm->field.sle_next =				\
+		    curelm->field.sle_next->field.sle_next;		\
+	}								\
+} while (/*CONSTCOND*/0)
+
+#define	SLIST_FOREACH(var, head, field)					\
+	for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
+
+/*
+ * Singly-linked List access methods.
+ */
+#define	SLIST_EMPTY(head)	((head)->slh_first == NULL)
+#define	SLIST_FIRST(head)	((head)->slh_first)
+#define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)
+
+
+/*
+ * Singly-linked Tail queue declarations.
+ */
+#define	STAILQ_HEAD(name, type)					\
+struct name {								\
+	struct type *stqh_first;	/* first element */			\
+	struct type **stqh_last;	/* addr of last next element */		\
+}
+
+#define	STAILQ_HEAD_INITIALIZER(head)					\
+	{ NULL, &(head).stqh_first }
+
+#define	STAILQ_ENTRY(type)						\
+struct {								\
+	struct type *stqe_next;	/* next element */			\
+}
+
+/*
+ * Singly-linked Tail queue functions.
+ */
+#define	STAILQ_INIT(head) do {						\
+	(head)->stqh_first = NULL;					\
+	(head)->stqh_last = &(head)->stqh_first;				\
+} while (/*CONSTCOND*/0)
+
+#define	STAILQ_INSERT_HEAD(head, elm, field) do {			\
+	if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)	\
+		(head)->stqh_last = &(elm)->field.stqe_next;		\
+	(head)->stqh_first = (elm);					\
+} while (/*CONSTCOND*/0)
+
+#define	STAILQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.stqe_next = NULL;					\
+	*(head)->stqh_last = (elm);					\
+	(head)->stqh_last = &(elm)->field.stqe_next;			\
+} while (/*CONSTCOND*/0)
+
+#define	STAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
+		(head)->stqh_last = &(elm)->field.stqe_next;		\
+	(listelm)->field.stqe_next = (elm);				\
+} while (/*CONSTCOND*/0)
+
+#define	STAILQ_REMOVE_HEAD(head, field) do {				\
+	if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
+		(head)->stqh_last = &(head)->stqh_first;			\
+} while (/*CONSTCOND*/0)
+
+#define	STAILQ_REMOVE(head, elm, type, field) do {			\
+	if ((head)->stqh_first == (elm)) {				\
+		STAILQ_REMOVE_HEAD((head), field);			\
+	} else {							\
+		struct type *curelm = (head)->stqh_first;		\
+		while (curelm->field.stqe_next != (elm))			\
+			curelm = curelm->field.stqe_next;		\
+		if ((curelm->field.stqe_next =				\
+			curelm->field.stqe_next->field.stqe_next) == NULL) \
+			    (head)->stqh_last = &(curelm)->field.stqe_next; \
+	}								\
+} while (/*CONSTCOND*/0)
+
+#define	STAILQ_FOREACH(var, head, field)				\
+	for ((var) = ((head)->stqh_first);				\
+		(var);							\
+		(var) = ((var)->field.stqe_next))
+
+#define	STAILQ_CONCAT(head1, head2) do {				\
+	if (!STAILQ_EMPTY((head2))) {					\
+		*(head1)->stqh_last = (head2)->stqh_first;		\
+		(head1)->stqh_last = (head2)->stqh_last;		\
+		STAILQ_INIT((head2));					\
+	}								\
+} while (/*CONSTCOND*/0)
+
+/*
+ * Singly-linked Tail queue access methods.
+ */
+#define	STAILQ_EMPTY(head)	((head)->stqh_first == NULL)
+#define	STAILQ_FIRST(head)	((head)->stqh_first)
+#define	STAILQ_NEXT(elm, field)	((elm)->field.stqe_next)
+
+
+/*
+ * Simple queue definitions.
+ */
+#define	SIMPLEQ_HEAD(name, type)					\
+struct name {								\
+	struct type *sqh_first;	/* first element */			\
+	struct type **sqh_last;	/* addr of last next element */		\
+}
+
+#define	SIMPLEQ_HEAD_INITIALIZER(head)					\
+	{ NULL, &(head).sqh_first }
+
+#define	SIMPLEQ_ENTRY(type)						\
+struct {								\
+	struct type *sqe_next;	/* next element */			\
+}
+
+/*
+ * Simple queue functions.
+ */
+#define	SIMPLEQ_INIT(head) do {						\
+	(head)->sqh_first = NULL;					\
+	(head)->sqh_last = &(head)->sqh_first;				\
+} while (/*CONSTCOND*/0)
+
+#define	SIMPLEQ_INSERT_HEAD(head, elm, field) do {			\
+	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)	\
+		(head)->sqh_last = &(elm)->field.sqe_next;		\
+	(head)->sqh_first = (elm);					\
+} while (/*CONSTCOND*/0)
+
+#define	SIMPLEQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.sqe_next = NULL;					\
+	*(head)->sqh_last = (elm);					\
+	(head)->sqh_last = &(elm)->field.sqe_next;			\
+} while (/*CONSTCOND*/0)
+
+#define	SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
+		(head)->sqh_last = &(elm)->field.sqe_next;		\
+	(listelm)->field.sqe_next = (elm);				\
+} while (/*CONSTCOND*/0)
+
+#define	SIMPLEQ_REMOVE_HEAD(head, field) do {				\
+	if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
+		(head)->sqh_last = &(head)->sqh_first;			\
+} while (/*CONSTCOND*/0)
+
+#define	SIMPLEQ_REMOVE(head, elm, type, field) do {			\
+	if ((head)->sqh_first == (elm)) {				\
+		SIMPLEQ_REMOVE_HEAD((head), field);			\
+	} else {							\
+		struct type *curelm = (head)->sqh_first;		\
+		while (curelm->field.sqe_next != (elm))			\
+			curelm = curelm->field.sqe_next;		\
+		if ((curelm->field.sqe_next =				\
+			curelm->field.sqe_next->field.sqe_next) == NULL) \
+			    (head)->sqh_last = &(curelm)->field.sqe_next; \
+	}								\
+} while (/*CONSTCOND*/0)
+
+#define	SIMPLEQ_FOREACH(var, head, field)				\
+	for ((var) = ((head)->sqh_first);				\
+		(var);							\
+		(var) = ((var)->field.sqe_next))
+
+/*
+ * Simple queue access methods.
+ */
+#define	SIMPLEQ_EMPTY(head)		((head)->sqh_first == NULL)
+#define	SIMPLEQ_FIRST(head)		((head)->sqh_first)
+#define	SIMPLEQ_NEXT(elm, field)	((elm)->field.sqe_next)
+
+
+/*
+ * Tail queue definitions.
+ */
+#define	_TAILQ_HEAD(name, type, qual)					\
+struct name {								\
+	qual type *tqh_first;		/* first element */		\
+	qual type *qual *tqh_last;	/* addr of last next element */	\
+}
+#define TAILQ_HEAD(name, type)	_TAILQ_HEAD(name, struct type,)
+
+#define	TAILQ_HEAD_INITIALIZER(head)					\
+	{ NULL, &(head).tqh_first }
+
+#define	_TAILQ_ENTRY(type, qual)					\
+struct {								\
+	qual type *tqe_next;		/* next element */		\
+	qual type *qual *tqe_prev;	/* address of previous next element */\
+}
+#define TAILQ_ENTRY(type)	_TAILQ_ENTRY(struct type,)
+
+/*
+ * Tail queue functions.
+ */
+#define	TAILQ_INIT(head) do {						\
+	(head)->tqh_first = NULL;					\
+	(head)->tqh_last = &(head)->tqh_first;				\
+} while (/*CONSTCOND*/0)
+
+#define	TAILQ_INSERT_HEAD(head, elm, field) do {			\
+	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)	\
+		(head)->tqh_first->field.tqe_prev =			\
+		    &(elm)->field.tqe_next;				\
+	else								\
+		(head)->tqh_last = &(elm)->field.tqe_next;		\
+	(head)->tqh_first = (elm);					\
+	(elm)->field.tqe_prev = &(head)->tqh_first;			\
+} while (/*CONSTCOND*/0)
+
+#define	TAILQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.tqe_next = NULL;					\
+	(elm)->field.tqe_prev = (head)->tqh_last;			\
+	*(head)->tqh_last = (elm);					\
+	(head)->tqh_last = &(elm)->field.tqe_next;			\
+} while (/*CONSTCOND*/0)
+
+#define	TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
+		(elm)->field.tqe_next->field.tqe_prev = 		\
+		    &(elm)->field.tqe_next;				\
+	else								\
+		(head)->tqh_last = &(elm)->field.tqe_next;		\
+	(listelm)->field.tqe_next = (elm);				\
+	(elm)->field.tqe_prev = &(listelm)->field.tqe_next;		\
+} while (/*CONSTCOND*/0)
+
+#define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
+	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
+	(elm)->field.tqe_next = (listelm);				\
+	*(listelm)->field.tqe_prev = (elm);				\
+	(listelm)->field.tqe_prev = &(elm)->field.tqe_next;		\
+} while (/*CONSTCOND*/0)
+
+#define	TAILQ_REMOVE(head, elm, field) do {				\
+	if (((elm)->field.tqe_next) != NULL)				\
+		(elm)->field.tqe_next->field.tqe_prev = 		\
+		    (elm)->field.tqe_prev;				\
+	else								\
+		(head)->tqh_last = (elm)->field.tqe_prev;		\
+	*(elm)->field.tqe_prev = (elm)->field.tqe_next;			\
+} while (/*CONSTCOND*/0)
+
+#define	TAILQ_FOREACH(var, head, field)					\
+	for ((var) = ((head)->tqh_first);				\
+		(var);							\
+		(var) = ((var)->field.tqe_next))
+
+#define	TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
+	for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));	\
+		(var);							\
+		(var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
+
+#define	TAILQ_CONCAT(head1, head2, field) do {				\
+	if (!TAILQ_EMPTY(head2)) {					\
+		*(head1)->tqh_last = (head2)->tqh_first;		\
+		(head2)->tqh_first->field.tqe_prev = (head1)->tqh_last;	\
+		(head1)->tqh_last = (head2)->tqh_last;			\
+		TAILQ_INIT((head2));					\
+	}								\
+} while (/*CONSTCOND*/0)
+
+/*
+ * Tail queue access methods.
+ */
+#define	TAILQ_EMPTY(head)		((head)->tqh_first == NULL)
+#define	TAILQ_FIRST(head)		((head)->tqh_first)
+#define	TAILQ_NEXT(elm, field)		((elm)->field.tqe_next)
+
+#define	TAILQ_LAST(head, headname) \
+	(*(((struct headname *)((head)->tqh_last))->tqh_last))
+#define	TAILQ_PREV(elm, headname, field) \
+	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+
+
+/*
+ * Circular queue definitions.
+ */
+#define	CIRCLEQ_HEAD(name, type)					\
+struct name {								\
+	struct type *cqh_first;		/* first element */		\
+	struct type *cqh_last;		/* last element */		\
+}
+
+#define	CIRCLEQ_HEAD_INITIALIZER(head)					\
+	{ (void *)&head, (void *)&head }
+
+#define	CIRCLEQ_ENTRY(type)						\
+struct {								\
+	struct type *cqe_next;		/* next element */		\
+	struct type *cqe_prev;		/* previous element */		\
+}
+
+/*
+ * Circular queue functions.
+ */
+#define	CIRCLEQ_INIT(head) do {						\
+	(head)->cqh_first = (void *)(head);				\
+	(head)->cqh_last = (void *)(head);				\
+} while (/*CONSTCOND*/0)
+
+#define	CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	(elm)->field.cqe_next = (listelm)->field.cqe_next;		\
+	(elm)->field.cqe_prev = (listelm);				\
+	if ((listelm)->field.cqe_next == (void *)(head))		\
+		(head)->cqh_last = (elm);				\
+	else								\
+		(listelm)->field.cqe_next->field.cqe_prev = (elm);	\
+	(listelm)->field.cqe_next = (elm);				\
+} while (/*CONSTCOND*/0)
+
+#define	CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {		\
+	(elm)->field.cqe_next = (listelm);				\
+	(elm)->field.cqe_prev = (listelm)->field.cqe_prev;		\
+	if ((listelm)->field.cqe_prev == (void *)(head))		\
+		(head)->cqh_first = (elm);				\
+	else								\
+		(listelm)->field.cqe_prev->field.cqe_next = (elm);	\
+	(listelm)->field.cqe_prev = (elm);				\
+} while (/*CONSTCOND*/0)
+
+#define	CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
+	(elm)->field.cqe_next = (head)->cqh_first;			\
+	(elm)->field.cqe_prev = (void *)(head);				\
+	if ((head)->cqh_last == (void *)(head))				\
+		(head)->cqh_last = (elm);				\
+	else								\
+		(head)->cqh_first->field.cqe_prev = (elm);		\
+	(head)->cqh_first = (elm);					\
+} while (/*CONSTCOND*/0)
+
+#define	CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.cqe_next = (void *)(head);				\
+	(elm)->field.cqe_prev = (head)->cqh_last;			\
+	if ((head)->cqh_first == (void *)(head))			\
+		(head)->cqh_first = (elm);				\
+	else								\
+		(head)->cqh_last->field.cqe_next = (elm);		\
+	(head)->cqh_last = (elm);					\
+} while (/*CONSTCOND*/0)
+
+#define	CIRCLEQ_REMOVE(head, elm, field) do {				\
+	if ((elm)->field.cqe_next == (void *)(head))			\
+		(head)->cqh_last = (elm)->field.cqe_prev;		\
+	else								\
+		(elm)->field.cqe_next->field.cqe_prev =			\
+		    (elm)->field.cqe_prev;				\
+	if ((elm)->field.cqe_prev == (void *)(head))			\
+		(head)->cqh_first = (elm)->field.cqe_next;		\
+	else								\
+		(elm)->field.cqe_prev->field.cqe_next =			\
+		    (elm)->field.cqe_next;				\
+} while (/*CONSTCOND*/0)
+
+#define	CIRCLEQ_FOREACH(var, head, field)				\
+	for ((var) = ((head)->cqh_first);				\
+		(var) != (const void *)(head);				\
+		(var) = ((var)->field.cqe_next))
+
+#define	CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
+	for ((var) = ((head)->cqh_last);				\
+		(var) != (const void *)(head);				\
+		(var) = ((var)->field.cqe_prev))
+
+/*
+ * Circular queue access methods.
+ */
+#define	CIRCLEQ_EMPTY(head)		((head)->cqh_first == (void *)(head))
+#define	CIRCLEQ_FIRST(head)		((head)->cqh_first)
+#define	CIRCLEQ_LAST(head)		((head)->cqh_last)
+#define	CIRCLEQ_NEXT(elm, field)	((elm)->field.cqe_next)
+#define	CIRCLEQ_PREV(elm, field)	((elm)->field.cqe_prev)
+
+#define CIRCLEQ_LOOP_NEXT(head, elm, field)				\
+	(((elm)->field.cqe_next == (void *)(head))			\
+	    ? ((head)->cqh_first)					\
+	    : (elm->field.cqe_next))
+#define CIRCLEQ_LOOP_PREV(head, elm, field)				\
+	(((elm)->field.cqe_prev == (void *)(head))			\
+	    ? ((head)->cqh_last)					\
+	    : (elm->field.cqe_prev))
+
+#endif	/* sys/queue.h */
diff --git a/nif_helpers.c b/nif_helpers.c
new file mode 100644
index 0000000..f29d76d
--- /dev/null
+++ b/nif_helpers.c
@@ -0,0 +1,195 @@
+// Copyright (c) 2014-2015, Loïc Hoguin <[email protected]>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#include "nif_helpers.h"
+#include <sys/queue.h>
+#include <stdarg.h>
+
+extern ERL_NIF_TERM atom_ok;
+extern ERL_NIF_TERM atom__nif_thread_ret_;
+
+typedef struct nif_thread_message {
+	TAILQ_ENTRY(nif_thread_message) next_entry;
+
+	ErlNifPid* from_pid;
+	void* function;
+	nif_thread_arg* args;
+} nif_thread_message;
+
+typedef TAILQ_HEAD(nif_thread_mailbox, nif_thread_message) nif_thread_mailbox;
+
+typedef struct {
+	ErlNifTid tid;
+	ErlNifMutex* lock;
+	ErlNifCond* cond;
+	nif_thread_mailbox* mailbox;
+} nif_thread_state;
+
+// Message.
+
+static nif_thread_message* nif_thread_message_alloc(void* f, nif_thread_arg* args, ErlNifPid* pid)
+{
+	nif_thread_message* msg = (nif_thread_message*)enif_alloc(sizeof(nif_thread_message));
+
+	msg->from_pid = pid;
+	msg->function = f;
+	msg->args = args;
+
+	return msg;
+}
+
+static void nif_thread_message_free(nif_thread_message* msg)
+{
+	enif_free(msg->from_pid);
+	enif_free(msg->args);
+	enif_free(msg);
+}
+
+// Calls and casts.
+
+static ERL_NIF_TERM nif_thread_send(nif_thread_state* st, nif_thread_message* msg)
+{
+	enif_mutex_lock(st->lock);
+
+	TAILQ_INSERT_TAIL(st->mailbox, msg, next_entry);
+
+	enif_cond_signal(st->cond);
+	enif_mutex_unlock(st->lock);
+
+	return atom_ok;
+}
+
+ERL_NIF_TERM nif_thread_cast(ErlNifEnv* env, void (*f)(nif_thread_arg*), int a, ...)
+{
+	va_list ap;
+	int i;
+
+	nif_thread_arg* args = (nif_thread_arg*)enif_alloc(a * sizeof(nif_thread_arg));
+
+	va_start(ap, a);
+	for (i = 0; i < a; i++)
+		args[i] = va_arg(ap, void*);
+	va_end(ap);
+
+	nif_thread_message* msg = nif_thread_message_alloc(f, args, NULL);
+
+	return nif_thread_send((nif_thread_state*)enif_priv_data(env), msg);
+}
+
+ERL_NIF_TERM nif_thread_call(ErlNifEnv* env, ERL_NIF_TERM (*f)(ErlNifEnv*, nif_thread_arg*), int a, ...)
+{
+	va_list ap;
+	int i;
+
+	nif_thread_arg* args = (nif_thread_arg*)enif_alloc(a * sizeof(nif_thread_arg));
+
+	va_start(ap, a);
+	for (i = 0; i < a; i++)
+		args[i] = va_arg(ap, void*);
+	va_end(ap);
+
+	ErlNifPid* pid = (ErlNifPid*)enif_alloc(sizeof(ErlNifPid));
+	nif_thread_message* msg = nif_thread_message_alloc((void*)f, args, enif_self(env, pid));
+
+	return nif_thread_send((nif_thread_state*)enif_priv_data(env), msg);
+}
+
+// Main thread loop.
+
+static int nif_thread_receive(nif_thread_state* st, nif_thread_message** msg)
+{
+	enif_mutex_lock(st->lock);
+
+	while (TAILQ_EMPTY(st->mailbox))
+		enif_cond_wait(st->cond, st->lock);
+
+	*msg = TAILQ_FIRST(st->mailbox);
+	TAILQ_REMOVE(st->mailbox, TAILQ_FIRST(st->mailbox), next_entry);
+
+	enif_mutex_unlock(st->lock);
+
+	if ((*msg)->function == NULL)
+		return 0;
+
+	return 1;
+}
+
+static void nif_thread_handle(ErlNifEnv* env, nif_thread_state* st, nif_thread_message* msg)
+{
+	if (msg->from_pid == NULL) {
+		void (*cast)(nif_thread_arg*) = msg->function;
+		cast(msg->args);
+	} else {
+		ERL_NIF_TERM (*call)(ErlNifEnv*, nif_thread_arg*) = msg->function;
+		ERL_NIF_TERM ret = call(env, msg->args);
+
+		enif_send(NULL, msg->from_pid, env,
+			enif_make_tuple2(env, atom__nif_thread_ret_, ret));
+
+		enif_clear_env(env);
+	}
+
+	nif_thread_message_free(msg);
+}
+
+static void* nif_main_thread(void* obj)
+{
+	ErlNifEnv* env = enif_alloc_env();
+	nif_thread_state* st = (nif_thread_state*)obj;
+	nif_thread_message* msg;
+
+	while (nif_thread_receive(st, &msg))
+		nif_thread_handle(env, st, msg);
+
+	enif_free_env(env);
+
+	return NULL;
+}
+
+// Main thread creation/destruction.
+
+void* nif_create_main_thread(char* name)
+{
+	nif_thread_state* st = (nif_thread_state*)enif_alloc(sizeof(nif_thread_state));
+
+	st->lock = enif_mutex_create("nif_thread_mailbox_lock");
+	st->cond = enif_cond_create("nif_thread_mailbox_cond");
+	st->mailbox = (nif_thread_mailbox*)enif_alloc(sizeof(nif_thread_mailbox));
+	TAILQ_INIT(st->mailbox);
+
+#if defined(__APPLE__) && defined(__MACH__)
+	// On OSX we identify ourselves as the main thread to ensure that
+	// we are compatible with libraries that require it. For example
+	// this is necessary with SDL2 in order to receive input events.
+	erl_drv_steal_main_thread(name, &(st->tid), nif_main_thread, st, NULL);
+#else
+	enif_thread_create(name, &(st->tid), nif_main_thread, st, NULL);
+#endif
+
+	return (void*)st;
+}
+
+void nif_destroy_main_thread(void* void_st)
+{
+	nif_thread_state* st = (nif_thread_state*)void_st;
+	nif_thread_message* msg = nif_thread_message_alloc(NULL, NULL, NULL);
+
+	nif_thread_send(st, msg);
+	enif_thread_join(st->tid, NULL);
+
+	enif_cond_destroy(st->cond);
+	enif_mutex_destroy(st->lock);
+	enif_free(st->mailbox);
+	enif_free(st);
+}
diff --git a/nif_helpers.h b/nif_helpers.h
new file mode 100644
index 0000000..2eefec6
--- /dev/null
+++ b/nif_helpers.h
@@ -0,0 +1,139 @@
+// Copyright (c) 2014-2015, Loïc Hoguin <[email protected]>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#ifndef __NIF_HELPERS_H__
+#define __NIF_HELPERS_H__
+
+#include "erl_nif.h"
+
+#define TO_STRING(i) #i
+
+// Atoms.
+
+#define MAX_ATOM_LENGTH 255
+
+#define NIF_ATOM_DECL(a) ERL_NIF_TERM atom_ ## a;
+#define NIF_ATOM_H_DECL(a) extern ERL_NIF_TERM atom_ ## a;
+#define NIF_ATOM_INIT(a) atom_ ## a = enif_make_atom(env, #a);
+
+// Functions.
+
+#ifndef NIF_FUNCTION_NAME
+#define NIF_FUNCTION_NAME(n) n
+#endif
+
+#define NIF_FUNCTION(f) \
+	ERL_NIF_TERM NIF_FUNCTION_NAME(f)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+#define NIF_FUNCTION_ARRAY(f, a) {#f, a, NIF_FUNCTION_NAME(f)},
+#define NIF_FUNCTION_H_DECL(f, a) \
+	ERL_NIF_TERM NIF_FUNCTION_NAME(f)(ErlNifEnv*, int, const ERL_NIF_TERM []);
+
+#define BADARG_IF(cond) if (cond) return enif_make_badarg(env)
+
+// Resources.
+
+#ifndef NIF_RES_TYPE
+#define NIF_RES_TYPE(t) t
+#endif
+
+#define NIF_RES_DECL(r) ErlNifResourceType* res_ ## r = NULL;
+#define NIF_RES_H_DECL(r) \
+	extern ErlNifResourceType* res_ ## r; \
+	void dtor_ ## r(ErlNifEnv*, void*); \
+	typedef struct { \
+		NIF_RES_TYPE(r)* v; \
+		void* dep; \
+	} obj_ ## r;
+#define NIF_RES_INIT(r) \
+	res_ ## r = enif_open_resource_type(env, NULL, TO_STRING(NIF_RES_TYPE(r)), dtor_ ## r, ERL_NIF_RT_CREATE, NULL); \
+	if (!res_ ## r) return -1;
+
+#define NIF_RES_GET(r, obj) (((obj_ ## r*)obj)->v)
+#define NIF_RES_DEP(r, obj) (((obj_ ## r*)obj)->dep)
+#define NIF_RES_TO_TERM(r, val, term) NIF_RES_TO_TERM_WITH_DEP(r, val, term, NULL)
+#define NIF_RES_TO_TERM_WITH_DEP(r, val, term, dep_res) { \
+	obj_ ## r* res = enif_alloc_resource(res_ ## r, sizeof(obj_ ## r)); \
+	res->v = val; \
+	res->dep = dep_res; \
+	term = enif_make_resource(env, res); \
+	enif_release_resource(res); \
+}
+
+// Function generators.
+
+#define NIF_ATOM_TO_FLAG(a, f) if (enif_is_identical(atom_ ## a, head)) *flags |= f; else
+#define NIF_LIST_TO_FLAGS_FUNCTION(f, type, flags_list) \
+	int f(ErlNifEnv* env, ERL_NIF_TERM list, type* flags) \
+	{ \
+		ERL_NIF_TERM head; \
+		\
+		if (!enif_is_list(env, list)) \
+			return 0; \
+		\
+		while (enif_get_list_cell(env, list, &head, &list)) { \
+			flags_list(NIF_ATOM_TO_FLAG) /* else */ return 0; \
+		} \
+		\
+		return 1; \
+	}
+
+#define NIF_FLAG_CONS_LIST(a, f) if (flags & f) list = enif_make_list_cell(env, atom_ ## a, list);
+#define NIF_FLAGS_TO_LIST_FUNCTION(f, type, flags_list) \
+	ERL_NIF_TERM f(ErlNifEnv* env, type flags) \
+	{ \
+		ERL_NIF_TERM list = enif_make_list(env, 0); \
+		flags_list(NIF_FLAG_CONS_LIST); \
+		return list; \
+	}
+
+#define NIF_ATOM_TO_ENUM(a, e) if (enif_is_identical(atom_ ## a, atom)) { *val = e; return 1; }
+#define NIF_ATOM_TO_ENUM_FUNCTION(f, type, enum_list) \
+	int f(ErlNifEnv* env, ERL_NIF_TERM atom, type* val) \
+	{ \
+		enum_list(NIF_ATOM_TO_ENUM) \
+		\
+		return 0; \
+	}
+#define NIF_ATOM_TO_ENUM_FUNCTION_DECL(f, type) int f(ErlNifEnv*, ERL_NIF_TERM, type*);
+
+#define NIF_ENUM_TO_ATOM(a, e) if (id == e) return atom_ ## a;
+#define NIF_ENUM_TO_ATOM_FUNCTION(f, type, enum_list) \
+	ERL_NIF_TERM f(type id) \
+	{ \
+		enum_list(NIF_ENUM_TO_ATOM) \
+		return atom_undefined; \
+	}
+#define NIF_ENUM_TO_ATOM_FUNCTION_DECL(f, type) ERL_NIF_TERM f(type);
+
+// Threaded NIFs.
+
+typedef void* nif_thread_arg;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void* nif_create_main_thread(char*);
+void nif_destroy_main_thread(void*);
+ERL_NIF_TERM nif_thread_cast(ErlNifEnv*, void (*f)(nif_thread_arg*), int a, ...);
+ERL_NIF_TERM nif_thread_call(ErlNifEnv*, ERL_NIF_TERM (*f)(ErlNifEnv*, nif_thread_arg*), int a, ...);
+
+#ifdef __cplusplus
+}
+#endif
+
+#define NIF_CAST_HANDLER(f) static void f(nif_thread_arg* args)
+#define NIF_CALL_HANDLER(f) static ERL_NIF_TERM f(ErlNifEnv* env, nif_thread_arg* args)
+
+#endif
diff --git a/plugins.mk b/plugins.mk
new file mode 100644
index 0000000..56903d7
--- /dev/null
+++ b/plugins.mk
@@ -0,0 +1,10 @@
+THIS := $(dir $(realpath $(lastword $(MAKEFILE_LIST))))
+
+SOURCES += $(THIS)nif_helpers.c
+$(C_SRC_OUTPUT_FILE): $(THIS)nif_helpers.o
+
+ifeq ($(PLATFORM),msys2)
+	CFLAGS += -I"$(THIS)/compat/"
+endif
+
+CFLAGS += -I"$(THIS)"