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diff --git a/nif_helpers.h b/nif_helpers.h
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+// 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