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OTP-8335 NIF improvements:
 Driver API for multi-threading made available for NIFs. Support for mempory managed (garbage collected) resource objects. A way to pass "pointers" to native data structures between C and Erlang in a safe way. Support for references, floats and term comparison. Various new functions, like enif_inspect_iolist_as_binary, enif_make_sub_binary, enif_get_string, enif_get_atom, enif_make_tuple_from_array, enif_make_list_from_array, enif_make_existing_atom.
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‎erts/example/matrix_nif.c

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/*
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* %CopyrightBegin%
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*
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* Copyright Ericsson AB 2010. All Rights Reserved.
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*
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* The contents of this file are subject to the Erlang Public License,
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* Version 1.1, (the "License"); you may not use this file except in
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* compliance with the License. You should have received a copy of the
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* Erlang Public License along with this software. If not, it can be
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* retrieved online at http://www.erlang.org/.
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*
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* Software distributed under the License is distributed on an "AS IS"
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* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
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* the License for the specific language governing rights and limitations
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* under the License.
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*
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* %CopyrightEnd%
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*/
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/*
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* Purpose: Simple example of NIFs using resource objects to implement functions
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* for matrix calculations.
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*/
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#include "erl_nif.h"
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#include <stddef.h>
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#include <assert.h>
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typedef struct
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{
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unsigned nrows;
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unsigned ncols;
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double* data;
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}Matrix;
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#define POS(MX, ROW, COL) ((MX)->data[(ROW)* (MX)->ncols + (COL)])
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static int get_number(ErlNifEnv* env, ERL_NIF_TERM term, double* dp);
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static Matrix* alloc_matrix(ErlNifEnv* env, unsigned nrows, unsigned ncols);
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static void matrix_dtor(ErlNifEnv* env, void* obj);
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static ErlNifResourceType* resource_type = NULL;
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static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
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{
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ErlNifResourceType* rt = enif_open_resource_type(env, "matrix_nif_example",
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matrix_dtor,
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ERL_NIF_RT_CREATE, NULL);
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if (rt == NULL) {
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return -1;
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}
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assert(resource_type == NULL);
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resource_type = rt;
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return 0;
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}
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static ERL_NIF_TERM create(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
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{
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/* create(Nrows, Ncolumns, [[first row],[second row],...,[last row]]) -> Matrix */
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unsigned nrows, ncols;
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unsigned i, j;
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ERL_NIF_TERM list, row, ret;
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Matrix* mx = NULL;
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if (!enif_get_uint(env, argv[0], &nrows) || nrows < 1 ||
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!enif_get_uint(env, argv[1], &ncols) || ncols < 1) {
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goto badarg;
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}
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mx = alloc_matrix(env, nrows, ncols);
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list = argv[2];
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for (i = 0; i<nrows; i++) {
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if (!enif_get_list_cell(env, list, &row, &list)) {
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goto badarg;
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}
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for (j = 0; j<ncols; j++) {
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ERL_NIF_TERM v;
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if (!enif_get_list_cell(env, row, &v, &row) ||
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!get_number(env, v, &POS(mx,i,j))) {
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goto badarg;
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}
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}
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if (!enif_is_empty_list(env, row)) {
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goto badarg;
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}
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}
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if (!enif_is_empty_list(env, list)) {
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goto badarg;
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}
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ret = enif_make_resource(env, mx);
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enif_release_resource(env, mx);
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return ret;
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badarg:
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if (mx != NULL) {
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enif_release_resource(env,mx);
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}
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return enif_make_badarg(env);
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}
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static ERL_NIF_TERM pos(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
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{
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/* pos(Matrix, Row, Column) -> float() */
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Matrix* mx;
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unsigned i, j;
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if (!enif_get_resource(env, argv[0], resource_type, (void**)&mx) ||
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!enif_get_uint(env, argv[1], &i) || (--i >= mx->nrows) ||
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!enif_get_uint(env, argv[2], &j) || (--j >= mx->ncols)) {
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return enif_make_badarg(env);
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}
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return enif_make_double(env, POS(mx, i,j));
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}
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static ERL_NIF_TERM add(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
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{
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/* add(Matrix_A, Matrix_B) -> Matrix_Sum */
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unsigned i, j;
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ERL_NIF_TERM ret;
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Matrix* mxA = NULL;
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Matrix* mxB = NULL;
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Matrix* mxS = NULL;
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if (!enif_get_resource(env, argv[0], resource_type, (void**)&mxA) ||
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!enif_get_resource(env, argv[1], resource_type, (void**)&mxB) ||
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mxA->nrows != mxB->nrows ||
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mxB->ncols != mxB->ncols) {
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return enif_make_badarg(env);
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}
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mxS = alloc_matrix(env, mxA->nrows, mxA->ncols);
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for (i = 0; i < mxA->nrows; i++) {
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for (j = 0; j < mxA->ncols; j++) {
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POS(mxS, i, j) = POS(mxA, i, j) + POS(mxB, i, j);
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}
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}
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ret = enif_make_resource(env, mxS);
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enif_release_resource(env, mxS);
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return ret;
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}
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static ERL_NIF_TERM size_of(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
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{
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/* size(Matrix) -> {Nrows, Ncols} */
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Matrix* mx;
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if (!enif_get_resource(env, argv[0], resource_type, (void**)&mx)) {
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return enif_make_badarg(env);
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}
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return enif_make_tuple2(env, enif_make_uint(env, mx->nrows),
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enif_make_uint(env, mx->ncols));
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}
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static ERL_NIF_TERM to_term(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
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{
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/* to_term(Matrix) -> [[first row], [second row], ...,[last row]] */
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unsigned i, j;
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ERL_NIF_TERM res;
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Matrix* mx = NULL;
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if (!enif_get_resource(env, argv[0], resource_type, (void**)&mx)) {
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return enif_make_badarg(env);
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}
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res = enif_make_list(env, 0);
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for (i = mx->nrows; i-- > 0; ) {
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ERL_NIF_TERM row = enif_make_list(env, 0);
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for (j = mx->ncols; j-- > 0; ) {
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row = enif_make_list_cell(env, enif_make_double(env, POS(mx,i,j)),
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row);
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}
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res = enif_make_list_cell(env, row, res);
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}
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return res;
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}
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static int get_number(ErlNifEnv* env, ERL_NIF_TERM term, double* dp)
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{
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long i;
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return enif_get_double(env, term, dp) ||
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(enif_get_long(env, term, &i) && (*dp=(double)i, 1));
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}
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static Matrix* alloc_matrix(ErlNifEnv* env, unsigned nrows, unsigned ncols)
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{
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Matrix* mx = enif_alloc_resource(env, resource_type, sizeof(Matrix));
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mx->nrows = nrows;
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mx->ncols = ncols;
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mx->data = enif_alloc(env, nrows*ncols*sizeof(double));
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return mx;
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}
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static void matrix_dtor(ErlNifEnv* env, void* obj)
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{
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Matrix* mx = (Matrix*) obj;
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enif_free(env, mx->data);
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mx->data = NULL;
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}
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static ErlNifFunc nif_funcs[] =
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{
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{"create", 3, create},
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{"pos", 3, pos},
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{"add", 2, add},
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{"size_of", 1, size_of},
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{"to_term", 1, to_term}
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};
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ERL_NIF_INIT(matrix_nif,nif_funcs,load,NULL,NULL,NULL);
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‎erts/example/matrix_nif.erl

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%%
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%% %CopyrightBegin%
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%%
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%% Copyright Ericsson AB 2010. All Rights Reserved.
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%%
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%% The contents of this file are subject to the Erlang Public License,
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%% Version 1.1, (the "License"); you may not use this file except in
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%% compliance with the License. You should have received a copy of the
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%% Erlang Public License along with this software. If not, it can be
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%% retrieved online at http://www.erlang.org/.
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%%
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%% Software distributed under the License is distributed on an "AS IS"
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%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
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%% the License for the specific language governing rights and limitations
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%% under the License.
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%%
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%% %CopyrightEnd%
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%%
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%%
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%% Purpose: Simple example of NIFs using resource objects to implement functions
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%% for matrix calculations.
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-module(matrix_nif).
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-export([create/3, pos/3, add/2, size_of/1, to_term/1]).
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-define(nif, nif_error(?LINE)).
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-on_load(on_load/0).
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on_load() ->
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erlang:load_nif("./matrix_nif", 0).
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%% NIFs
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create(_Rows, _Cols, _RowList) -> ?nif.
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pos(_Mx, _Row, _Col) -> ?nif.
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add(_MxA, _MxB) -> ?nif.
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size_of(_Mx) -> ?nif.
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to_term(_Mx) -> ?nif.
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nif_error(Line) ->
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erlang:error({"NIF not implemented in matrix_nif at line", Line}).
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