new IP assignment, random init, fifo reuse of IP

Initialized the free IP pool with a random order and time stamp to
build a queue in the ets table. Released IPs are appended to the end
of the free queue (through the timestamp).

apps/ergw_core/c_src/Makefile

@@ -0,0 +1,74 @@
+# Based on c_src.mk from erlang.mk by Loic Hoguin <essen@ninenines.eu>
+
+CURDIR := $(shell pwd)
+BASEDIR := $(abspath $(CURDIR)/..)
+
+PROJECT ?= $(notdir $(BASEDIR))
+PROJECT := $(strip $(PROJECT))
+
+ERTS_INCLUDE_DIR ?= $(shell erl -noshell -eval "io:format(\"~ts/erts-~ts/include/\", [code:root_dir(), erlang:system_info(version)])." -s init stop)
+ERL_INTERFACE_INCLUDE_DIR ?= $(shell erl -noshell -eval "io:format(\"~ts\", [code:lib_dir(erl_interface, include)])." -s init stop)
+ERL_INTERFACE_LIB_DIR ?= $(shell erl -noshell -eval "io:format(\"~ts\", [code:lib_dir(erl_interface, lib)])." -s init stop)
+
+C_SRC_DIR = $(CURDIR)
+C_SRC_OUTPUT ?= $(CURDIR)/../priv/$(PROJECT).so
+
+# System type and C compiler/flags.
+
+UNAME_SYS := $(shell uname -s)
+ifeq ($(UNAME_SYS), Darwin)
+	CC ?= cc
+	CFLAGS ?= -O3 -std=c99 -arch x86_64 -finline-functions -Wall -Wmissing-prototypes
+	CXXFLAGS ?= -O3 -arch x86_64 -finline-functions -Wall
+	LDFLAGS ?= -arch x86_64 -flat_namespace -undefined suppress
+else ifeq ($(UNAME_SYS), FreeBSD)
+	CC ?= cc
+	CFLAGS ?= -O3 -std=c99 -finline-functions -Wall -Wmissing-prototypes
+	CXXFLAGS ?= -O3 -finline-functions -Wall
+else ifeq ($(UNAME_SYS), Linux)
+	CC ?= gcc
+	CFLAGS ?= -O3 -std=c99 -finline-functions -Wall -Wmissing-prototypes
+	CXXFLAGS ?= -O3 -finline-functions -Wall
+endif
+
+CFLAGS += -fPIC -I $(ERTS_INCLUDE_DIR) -I $(ERL_INTERFACE_INCLUDE_DIR)
+CXXFLAGS += -fPIC -I $(ERTS_INCLUDE_DIR) -I $(ERL_INTERFACE_INCLUDE_DIR)
+
+LDLIBS += -L $(ERL_INTERFACE_LIB_DIR) -lei
+LDFLAGS += -shared
+
+# Verbosity.
+
+c_verbose_0 = @echo " C     " $(?F);
+c_verbose = $(c_verbose_$(V))
+
+cpp_verbose_0 = @echo " CPP   " $(?F);
+cpp_verbose = $(cpp_verbose_$(V))
+
+link_verbose_0 = @echo " LD    " $(@F);
+link_verbose = $(link_verbose_$(V))
+
+SOURCES := $(shell find $(C_SRC_DIR) -type f \( -name "*.c" -o -name "*.C" -o -name "*.cc" -o -name "*.cpp" \))
+OBJECTS = $(addsuffix .o, $(basename $(SOURCES)))
+
+COMPILE_C = $(c_verbose) $(CC) $(CFLAGS) $(CPPFLAGS) -c
+COMPILE_CPP = $(cpp_verbose) $(CXX) $(CXXFLAGS) $(CPPFLAGS) -c
+
+$(C_SRC_OUTPUT): $(OBJECTS)
+	@mkdir -p $(BASEDIR)/priv/
+	$(link_verbose) $(CC) $(OBJECTS) $(LDFLAGS) $(LDLIBS) -o $(C_SRC_OUTPUT)
+
+%.o: %.c
+	$(COMPILE_C) $(OUTPUT_OPTION) $<
+
+%.o: %.cc
+	$(COMPILE_CPP) $(OUTPUT_OPTION) $<
+
+%.o: %.C
+	$(COMPILE_CPP) $(OUTPUT_OPTION) $<
+
+%.o: %.cpp
+	$(COMPILE_CPP) $(OUTPUT_OPTION) $<
+
+clean:
+	@rm -f $(C_SRC_OUTPUT) $(OBJECTS)

apps/ergw_core/c_src/uint32_fy_shuffle.c

@@ -0,0 +1,202 @@
+/* Copyright 2021, Travelping GmbH <info@travelping.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/* Generate a sequence of at most 2^32 unsigned 32bit integers using the
+ * Fisher-Yates shuffle */
+
+#include <erl_nif.h>
+#include <stdint.h>
+#include <time.h>
+
+#define STEPCNT (4*1024)
+
+#define min(x,y) (				    \
+    { __auto_type __x = (x); __auto_type __y = (y); \
+      __x < __y ? __x : __y; })
+
+static ERL_NIF_TERM
+mk_atom(ErlNifEnv* env, const char* atom)
+{
+    ERL_NIF_TERM ret;
+
+    if(!enif_make_existing_atom(env, atom, &ret, ERL_NIF_LATIN1))
+    {
+	return enif_make_atom(env, atom);
+    }
+
+    return ret;
+}
+
+static void swap (unsigned int *a, unsigned int *b)
+{
+    unsigned int temp = *a;
+    *a = *b;
+    *b = temp;
+}
+
+static ERL_NIF_TERM shuffle_ret(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ERL_NIF_TERM new_argv[4];
+    ERL_NIF_TERM head, tail;
+    unsigned int i, n, end;
+    unsigned int *arr;
+    ErlNifBinary bin;
+
+    if (argc != 4 ||
+	!enif_get_uint(env, argv[0], &n) || n <= 0 ||
+	!enif_get_uint(env, argv[1], &i) || i > n ||
+	!enif_inspect_binary(env, argv[2], &bin) ||
+	!enif_is_list(env, argv[3]))
+	return enif_make_badarg(env);
+
+    /* printf("ret i: %u\n\r", i); */
+    /* printf("ret n: %u\n\r", n); */
+
+    tail = argv[3];
+    end = min(n, i + STEPCNT);
+    arr = (unsigned int *)bin.data;
+
+    for (; i < end; i++) {
+	head = enif_make_tuple1(env,
+				enif_make_tuple2(env,
+						 enif_make_int64(env, INT64_MIN + i),
+						 enif_make_uint(env, arr[i])));
+	tail = enif_make_list_cell(env, head, tail);
+    }
+
+    if (i >= n) {
+	enif_release_binary(&bin);
+	return tail;
+    } else {
+	new_argv[0] = argv[0];
+	new_argv[1] = enif_make_uint(env, i);
+	new_argv[2] = argv[2];
+	new_argv[3] = tail;
+	return enif_schedule_nif(env, "shuffle_ret", 0, shuffle_ret, 4, new_argv);
+    }
+}
+
+static ERL_NIF_TERM shuffle_randomize(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ERL_NIF_TERM new_argv[4];
+    unsigned int i, n, end;
+    unsigned int *arr;
+    ErlNifBinary bin;
+
+    if (argc != 3 ||
+	!enif_get_uint(env, argv[0], &n) || n <= 0 ||
+	!enif_get_uint(env, argv[1], &i) || i > n ||
+	!enif_inspect_binary(env, argv[2], &bin))
+	return enif_make_badarg(env);
+
+    if (i == n - 1)
+	srand(time(NULL));
+
+    end = (i > STEPCNT) ? i - STEPCNT : 0;
+    arr = (unsigned int *)bin.data;
+
+    for (; i > end; i--) {
+	unsigned int j = rand() % (i+1);
+	swap(&arr[i], &arr[j]);
+    }
+
+    new_argv[0] = argv[0];
+    new_argv[2] = argv[2];
+
+    if (i == 0) {
+	new_argv[1] = enif_make_uint(env, 0);
+	new_argv[3] = enif_make_list(env, 0);
+	return enif_schedule_nif(env, "shuffle_ret", 0, shuffle_ret, 4, new_argv);
+    } else {
+	new_argv[1] = enif_make_uint(env, i);
+	return enif_schedule_nif(env, "shuffle_randomize", 0, shuffle_randomize, 3, new_argv);
+    }
+}
+
+static ERL_NIF_TERM shuffle_fill(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ERL_NIF_TERM new_argv[3];
+    unsigned int i, n, end;
+    unsigned int *arr;
+    ErlNifBinary bin;
+
+    if (argc != 3 ||
+	!enif_get_uint(env, argv[0], &n) || n <= 0 ||
+	!enif_get_uint(env, argv[1], &i) || i > n ||
+	!enif_inspect_binary(env, argv[2], &bin))
+	return enif_make_badarg(env);
+
+    /* printf("fill i: %u\r\n", i); */
+    /* printf("fill n: %u\r\n", n); */
+
+    end = min(n, i + STEPCNT);
+    arr = (unsigned int *)bin.data;
+
+    for (; i < end; i++)
+	arr[i] = i;
+
+    new_argv[0] = argv[0];
+    new_argv[2] = argv[2];
+
+    if (i == n) {
+	new_argv[1] = enif_make_uint(env, n - 1);
+	return enif_schedule_nif(env, "shuffle_randomize", 0, shuffle_randomize, 3, new_argv);
+    } else {
+	new_argv[1] = enif_make_uint(env, i);
+	return enif_schedule_nif(env, "shuffle_fill", 0, shuffle_fill, 3, new_argv);
+    }
+}
+
+static ERL_NIF_TERM shuffle(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ERL_NIF_TERM new_argv[3];
+    unsigned int n;
+
+    if (!enif_get_uint(env, argv[0], &n) || n <= 0)
+	return enif_make_badarg(env);
+
+    if (!(enif_make_new_binary(env, n * sizeof(unsigned int), &new_argv[2])))
+	return enif_raise_exception(env, mk_atom(env, "out_of_memory"));
+
+    new_argv[0] = argv[0];
+    new_argv[1] = enif_make_uint(env, 0);
+    return enif_schedule_nif(env, "shuffle_fill", 0, shuffle_fill, 3, new_argv);
+}
+
+#if 0
+static ERL_NIF_TERM shuffle(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ERL_NIF_TERM head, tail;
+    unsigned int *arr;
+    unsigned int i, n;
+
+    if (!enif_get_uint(env, argv[0], &n) || n <= 0)
+	return enif_make_badarg(env);
+
+    if (!(arr = enif_alloc(n * sizeof(arr[0]))))
+	return enif_raise_exception(env, mk_atom(env, "out_of_memory"));
+
+    for (i = 0; i < n; i++)
+	arr[i] = i;
+    //randomize(arr, n);
+
+    tail = enif_make_list(env, 0);
+    for (i = 0; i < n; i++) {
+	head = enif_make_uint(env, arr[i]);
+	tail = enif_make_list_cell(env, head, tail);
+    }
+    return tail;
+}
+#endif
+
+static ErlNifFunc nif_funcs[] =
+{
+	{"shuffle", 1, shuffle}
+};
+
+ERL_NIF_INIT(uint32_fy_shuffle, nif_funcs, NULL, NULL, NULL, NULL)

apps/ergw_core/rebar.config

@@ -0,0 +1,9 @@
+{erl_opts, [debug_info]}.
+{deps, []}.
+
+{pre_hooks,
+  [{"(linux|darwin|solaris)", compile, "make -C c_src"},
+   {"(freebsd)", compile, "gmake -C c_src"}]}.
+{post_hooks,
+  [{"(linux|darwin|solaris)", clean, "make -C c_src clean"},
+   {"(freebsd)", clean, "gmake -C c_src clean"}]}.