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.

1 files changed, 210 insertions, 0 deletions

diff --git a/erts/example/matrix_nif.c b/erts/example/matrix_nif.c
new file mode 100644
index 0000000000..c5e01dade5
--- /dev/null
+++ b/erts/example/matrix_nif.c
@@ -0,0 +1,210 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2010. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+/*
+ * Purpose: Simple example of NIFs using resource objects to implement functions
+ *          for matrix calculations.
+ */
+
+#include "erl_nif.h"
+
+#include <stddef.h>
+#include <assert.h>
+
+typedef struct
+{
+    unsigned nrows;
+    unsigned ncols;
+    double* data;
+}Matrix;
+
+#define POS(MX, ROW, COL) ((MX)->data[(ROW)* (MX)->ncols + (COL)])
+
+static int get_number(ErlNifEnv* env, ERL_NIF_TERM term, double* dp);
+static Matrix* alloc_matrix(ErlNifEnv* env, unsigned nrows, unsigned ncols);
+static void matrix_dtor(ErlNifEnv* env, void* obj);
+
+
+static ErlNifResourceType* resource_type = NULL;
+
+static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
+{
+    ErlNifResourceType* rt = enif_open_resource_type(env, "matrix_nif_example",
+						     matrix_dtor, 
+						     ERL_NIF_RT_CREATE, NULL);
+    if (rt == NULL) {
+	return -1;
+    }
+    assert(resource_type == NULL);
+    resource_type = rt;
+    return 0;
+}
+
+static ERL_NIF_TERM create(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    /* create(Nrows, Ncolumns, [[first row],[second row],...,[last row]]) -> Matrix */
+    unsigned nrows, ncols;
+    unsigned i, j;
+    ERL_NIF_TERM list, row, ret;
+    Matrix* mx = NULL;
+
+    if (!enif_get_uint(env, argv[0], &nrows) || nrows < 1 ||
+	!enif_get_uint(env, argv[1], &ncols) || ncols < 1) {
+
+	goto badarg;
+    }
+    mx = alloc_matrix(env, nrows, ncols);
+    list = argv[2];
+    for (i = 0; i<nrows; i++) {
+	if (!enif_get_list_cell(env, list, &row, &list)) {
+	    goto badarg;
+	}
+	for (j = 0; j<ncols; j++) {
+	    ERL_NIF_TERM v;
+	    if (!enif_get_list_cell(env, row, &v, &row) ||
+		!get_number(env, v, &POS(mx,i,j))) { 
+		goto badarg;
+	    }	    
+	}
+	if (!enif_is_empty_list(env, row)) {
+	    goto badarg;
+	}
+    }
+    if (!enif_is_empty_list(env, list)) {
+	goto badarg;
+    }
+
+    ret = enif_make_resource(env, mx);
+    enif_release_resource(env, mx);
+    return ret;
+
+badarg:
+    if (mx != NULL) {
+	enif_release_resource(env,mx);
+    }
+    return enif_make_badarg(env);
+}
+
+
+static ERL_NIF_TERM pos(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    /* pos(Matrix, Row, Column) -> float() */
+    Matrix* mx;
+    unsigned i, j;
+    if (!enif_get_resource(env, argv[0], resource_type, (void**)&mx) ||
+	!enif_get_uint(env, argv[1], &i) || (--i >= mx->nrows) ||
+	!enif_get_uint(env, argv[2], &j) || (--j >= mx->ncols)) {
+	return enif_make_badarg(env);
+    }
+    return enif_make_double(env, POS(mx, i,j));
+}
+
+static ERL_NIF_TERM add(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    /* add(Matrix_A, Matrix_B) -> Matrix_Sum */
+    unsigned i, j;
+    ERL_NIF_TERM ret;
+    Matrix* mxA = NULL;
+    Matrix* mxB = NULL;
+    Matrix* mxS = NULL;
+
+    if (!enif_get_resource(env, argv[0], resource_type, (void**)&mxA) ||
+	!enif_get_resource(env, argv[1], resource_type, (void**)&mxB) ||
+	mxA->nrows != mxB->nrows ||
+	mxB->ncols != mxB->ncols) {
+
+    	return enif_make_badarg(env);
+    }
+    mxS = alloc_matrix(env, mxA->nrows, mxA->ncols);
+    for (i = 0; i < mxA->nrows; i++) {
+	for (j = 0; j < mxA->ncols; j++) {
+	    POS(mxS, i, j) = POS(mxA, i, j) + POS(mxB, i, j);
+	}
+    }
+    ret = enif_make_resource(env, mxS);
+    enif_release_resource(env, mxS);
+    return ret;
+}
+
+static ERL_NIF_TERM size_of(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    /* size(Matrix) -> {Nrows, Ncols} */
+    Matrix* mx;
+    if (!enif_get_resource(env, argv[0], resource_type, (void**)&mx)) {
+	return enif_make_badarg(env);
+    }
+    return enif_make_tuple2(env, enif_make_uint(env, mx->nrows),
+			    enif_make_uint(env, mx->ncols));
+}
+
+static ERL_NIF_TERM to_term(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    /* to_term(Matrix) -> [[first row], [second row], ...,[last row]] */
+    unsigned i, j;
+    ERL_NIF_TERM res;
+    Matrix* mx = NULL;
+
+    if (!enif_get_resource(env, argv[0], resource_type, (void**)&mx)) {	
+    	return enif_make_badarg(env);
+    }
+    res = enif_make_list(env, 0);
+    for (i = mx->nrows; i-- > 0; ) {
+	ERL_NIF_TERM row = enif_make_list(env, 0);
+	for (j = mx->ncols; j-- > 0; ) {
+	    row = enif_make_list_cell(env, enif_make_double(env, POS(mx,i,j)),
+				      row);
+	}
+	res = enif_make_list_cell(env, row, res);
+    }
+    return res;
+}
+
+static int get_number(ErlNifEnv* env, ERL_NIF_TERM term, double* dp)
+{
+    long i;
+    return enif_get_double(env, term, dp) || 
+	(enif_get_long(env, term, &i) && (*dp=(double)i, 1));
+}
+
+static Matrix* alloc_matrix(ErlNifEnv* env, unsigned nrows, unsigned ncols)
+{
+    Matrix* mx = enif_alloc_resource(env, resource_type, sizeof(Matrix));
+    mx->nrows = nrows;
+    mx->ncols = ncols;
+    mx->data = enif_alloc(env, nrows*ncols*sizeof(double));
+    return mx;
+}
+
+static void matrix_dtor(ErlNifEnv* env, void* obj)
+{
+    Matrix* mx = (Matrix*) obj;
+    enif_free(env, mx->data);
+    mx->data = NULL;
+}
+
+static ErlNifFunc nif_funcs[] =
+{
+    {"create", 3, create},
+    {"pos", 3, pos},
+    {"add", 2, add},
+    {"size_of", 1, size_of},
+    {"to_term", 1, to_term}
+};
+
+ERL_NIF_INIT(matrix_nif,nif_funcs,load,NULL,NULL,NULL);
+