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c_src/nif_utils.c

// SPDX-FileCopyrightText: 2018 Frank Hunleth
// SPDX-FileCopyrightText: 2024 Connor Rigby
//
// SPDX-License-Identifier: Apache-2.0
#include "gpio_nif.h"
#include <erl_driver.h> // erl_errno_id
#include <errno.h>
#include <string.h>
ERL_NIF_TERM make_ok_tuple(ErlNifEnv *env, ERL_NIF_TERM value)
{
return enif_make_tuple2(env, atom_ok, value);
}
ERL_NIF_TERM make_errno_atom(ErlNifEnv *env, int errno_value)
{
// Handle return codes from functions that return -errno
if (errno_value < 0)
errno_value = -errno_value;
switch (errno_value) {
// For historical reasons, these errno values are translated to custom atoms
case ENOENT: return enif_make_atom(env, "not_found");
case EBUSY: return enif_make_atom(env, "already_open");
case EOPNOTSUPP: return enif_make_atom(env, "not_supported");
// Fallback to the plain errno name
default: return enif_make_atom(env, erl_errno_id(errno_value));
}
}
ERL_NIF_TERM make_errno_error(ErlNifEnv *env, int errno_value)
{
return enif_make_tuple2(env, atom_error, make_errno_atom(env, errno_value));
}
ERL_NIF_TERM make_string_binary(ErlNifEnv *env, const char *str)
{
ERL_NIF_TERM term;
size_t len = strlen(str);
unsigned char *data = enif_make_new_binary(env, len, &term);
memcpy(data, str, len);
return term;
}
int enif_get_boolean(ErlNifEnv *env, ERL_NIF_TERM term, bool *v)
{
char buffer[16];
if (enif_get_atom(env, term, buffer, sizeof(buffer), ERL_NIF_LATIN1) <= 0)
return false;
if (strcmp("false", buffer) == 0)
*v = false;
else
*v = true;
return true;
}