input-common.cpp

/*
 * input-common.cpp
 * common input handling routines
 *
 * Copyright (c) 2015-2018 Tomasz Lemiech <szpajder@gmail.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 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <iostream>
#include <assert.h>
#include <dlfcn.h>  		// dlopen, dlsym
#include <errno.h>
#include <pthread.h>
#include <stdio.h>  		// asprintf
#include <stdlib.h>		// free
#include <string.h>
#include "input-common.h"

using namespace std;

typedef input_t *(*input_new_func_t)(void);

input_t *input_new(char const * const type) {
	assert(type != NULL);
	void *dlhandle = dlopen(NULL, RTLD_NOW);
	assert(dlhandle != NULL);
	char *fname = NULL;
	assert(asprintf(&fname, "%s_input_new", type) > 0);
	input_new_func_t fptr = (input_new_func_t)dlsym(dlhandle, fname);
	free(fname);
	if(fptr == NULL) {
		return NULL;
	}
	input_t *input = (*fptr)();
	assert(input->init != NULL);
	assert(input->run_rx_thread != NULL);
	assert(input->set_centerfreq != NULL);
	return input;
}

int input_init(input_t * const input) {
	assert(input != NULL);
	input_state_t new_state = INPUT_FAILED;	// fail-safe default
	errno = 0;
	int ret = input->init(input);
	if(ret < 0) {
		ret = -1;
	} else if((ret = pthread_mutex_init(&input->buffer_lock, NULL)) != 0) {
		errno = ret;
		ret = -1;
	} else {
		new_state = INPUT_INITIALIZED;
		ret = 0;
	}
	input->state = new_state;
	return ret;
}

int input_start(input_t * const input) {
	assert(input != NULL);
	assert(input->dev_data != NULL);
	assert(input->state == INPUT_INITIALIZED);
	int err = pthread_create(&input->rx_thread, NULL, input->run_rx_thread, (void *)input);
	if(err != 0) {
		errno = err;
		return -1;
	}
	return 0;
}

int input_parse_config(input_t * const input, libconfig::Setting &cfg) {
	assert(input != NULL);
	if(input->parse_config != NULL) {
		return input->parse_config(input, cfg);
	} else {
// Very simple inputs (like stdin) might not necessarily have any configuration
// variables, so it's legal not to have parse_config defined.
		return 0;
	}
}

int input_stop(input_t * const input) {
	assert(input != NULL);
	assert(input->dev_data != NULL);
	int err = 0;
	errno = 0;
	if(input->state == INPUT_RUNNING && input->stop != NULL) {
		err = input->stop(input);
		if(err != 0) {
			input->state = INPUT_FAILED;
			return -1;
		}
	}
	input->state = INPUT_STOPPED;
	err = pthread_join(input->rx_thread, NULL);
	if(err != 0) {
		errno = err;
		return -1;
	}
	return 0;
}

int input_set_centerfreq(input_t * const input, int const centerfreq) {
	assert(input != NULL);
	assert(input->dev_data != NULL);
	if(input->state != INPUT_RUNNING) {
		return -1;
	}
	int ret = input->set_centerfreq(input, centerfreq);
	if(ret != 0) {
		input->state = INPUT_FAILED;
		return -1;
	}
	input->centerfreq = centerfreq;
	return 0;
}