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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2010-2011. 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;
/*
* Use a union for pointer type conversion to avoid compiler warnings
* about strict-aliasing violations with gcc-4.1. gcc >= 4.2 does not
* emit the warning.
* TODO: Reconsider use of union once gcc-4.1 is obsolete?
*/
typedef union
{
void* vp;
Matrix* p;
} mx_t;
#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, NULL,
"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(mx);
return ret;
badarg:
if (mx != NULL) {
enif_release_resource(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() */
mx_t mx;
unsigned i, j;
if (!enif_get_resource(env, argv[0], resource_type, &mx.vp) ||
!enif_get_uint(env, argv[1], &i) || (--i >= mx.p->nrows) ||
!enif_get_uint(env, argv[2], &j) || (--j >= mx.p->ncols)) {
return enif_make_badarg(env);
}
return enif_make_double(env, POS(mx.p, 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;
mx_t mxA, mxB, mxS;
mxA.p = NULL;
mxB.p = NULL;
mxS.p = NULL;
if (!enif_get_resource(env, argv[0], resource_type, &mxA.vp) ||
!enif_get_resource(env, argv[1], resource_type, &mxB.vp) ||
mxA.p->nrows != mxB.p->nrows ||
mxB.p->ncols != mxB.p->ncols) {
return enif_make_badarg(env);
}
mxS.p = alloc_matrix(env, mxA.p->nrows, mxA.p->ncols);
for (i = 0; i < mxA.p->nrows; i++) {
for (j = 0; j < mxA.p->ncols; j++) {
POS(mxS.p, i, j) = POS(mxA.p, i, j) + POS(mxB.p, i, j);
}
}
ret = enif_make_resource(env, mxS.p);
enif_release_resource(mxS.p);
return ret;
}
static ERL_NIF_TERM size_of(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
/* size(Matrix) -> {Nrows, Ncols} */
mx_t mx;
if (!enif_get_resource(env, argv[0], resource_type, &mx.vp)) {
return enif_make_badarg(env);
}
return enif_make_tuple2(env, enif_make_uint(env, mx.p->nrows),
enif_make_uint(env, mx.p->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;
mx_t mx;
mx.p = NULL;
if (!enif_get_resource(env, argv[0], resource_type, &mx.vp)) {
return enif_make_badarg(env);
}
res = enif_make_list(env, 0);
for (i = mx.p->nrows; i-- > 0; ) {
ERL_NIF_TERM row = enif_make_list(env, 0);
for (j = mx.p->ncols; j-- > 0; ) {
row = enif_make_list_cell(env, enif_make_double(env, POS(mx.p,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(resource_type, sizeof(Matrix));
mx->nrows = nrows;
mx->ncols = ncols;
mx->data = enif_alloc(nrows*ncols*sizeof(double));
return mx;
}
static void matrix_dtor(ErlNifEnv* env, void* obj)
{
Matrix* mx = (Matrix*) obj;
enif_free(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);
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