Switch to direct use of librtlsdr and PulseAudio

Substantial rework to replace the spawning of rtl_fm and aplay with direct
usage of librtlsdr and PulseAudio in a multi-threaded model. This is required
due to changes in AGL application execution that prevent spawned processes from
exiting, resulting in the plugin hanging on frequency changes or stopping.

The rework has been accomplished by refactoring the source of rtl_fm.c into a
reusable form and connecting it to the RtlFmRadioTunerControl class used to
implement the functionality exposed by the RtlFmRadioPlugin class. The idea for
reusing the source code in rtl_fm.c in this way is inspired by the older
qml_radio_plugin codebase, but a new refactor of rtl_fm.c was done to keep more
of its filtering functionality and ensure behavior consistent with the previous
implementation. The files radio_output.{h,cpp} are adapted from qml_radio_plugin
with some additional modifications.

Other changes include:
- The files in the convenience subdirectory have been copied from the librtldr
  source tree to reduce the effort of importing rtl_fm.c.
- The COPYING file containing the GPL license has been copied from the
  librtlsdr source tree to accompany rtl_fm.c and the convenience/* files.
- The recently added AM band support has been removed as the USB DVB adapters
  are incapable of receiving AM without significant tweaking, and a single
  adapter would be unable to do both AM and FM at the same time. The plugin
  now explicitly reports that it only supports FM.
- The list of known stations to act as an ersatz seeking implementation has
  been removed, as the updated higher-level QML application no longer exposes
  seeking. Adding this functionality back in would be straightforward if it
  becomes required again. There is also some code in rtl_fm.c that could possibly
  be adapted into a proper signal strength detection scheme in the future if
  that is desired.
- A Qt QSettings file is used to store the FM band plan information to
  allow using the specific frequency ranges for North America versus Japan.
  The band plan can be changed by modifying the "fmbandplan" entry in the
  QSettings .conf file to either "US" or "JP". The location of the .conf file
  can be one of:

  $HOME/.config/AGL/qtmultimedia-rtlfm-radio-plugin.conf
  $HOME/.config/AGL.conf
  /etc/xdg/AGL/qtmultimedia-rtlfm-radio-plugin.conf
  /etc/xdg/AGL.conf

Note that some debugging output has been left in place in the start and stop
methods to facilitate debugging of the higher-level QML application.  They will
be removed once that is complete.

Change-Id: I1d92c74eb24b24cb5416dd531b599645d1287295
Signed-off-by: Scott Murray <scott.murray@konsulko.com>

2 files changed, 446 insertions, 0 deletions

diff --git a/convenience/convenience.c b/convenience/convenience.c
new file mode 100644
index 0000000..517dc4e
--- /dev/null
+++ b/convenience/convenience.c
@@ -0,0 +1,304 @@
+/*
+ * Copyright (C) 2014 by Kyle Keen <keenerd@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 2 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/>.
+ */
+
+/* a collection of user friendly tools
+ * todo: use strtol for more flexible int parsing
+ * */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef _WIN32
+#include <unistd.h>
+#else
+#include <windows.h>
+#include <fcntl.h>
+#include <io.h>
+#define _USE_MATH_DEFINES
+#endif
+
+#include <math.h>
+
+#include "rtl-sdr.h"
+
+double atofs(char *s)
+/* standard suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(s);
+	last = s[len-1];
+	s[len-1] = '\0';
+	switch (last) {
+		case 'g':
+		case 'G':
+			suff *= 1e3;
+		case 'm':
+		case 'M':
+			suff *= 1e3;
+		case 'k':
+		case 'K':
+			suff *= 1e3;
+			suff *= atof(s);
+			s[len-1] = last;
+			return suff;
+	}
+	s[len-1] = last;
+	return atof(s);
+}
+
+double atoft(char *s)
+/* time suffixes, returns seconds */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(s);
+	last = s[len-1];
+	s[len-1] = '\0';
+	switch (last) {
+		case 'h':
+		case 'H':
+			suff *= 60;
+		case 'm':
+		case 'M':
+			suff *= 60;
+		case 's':
+		case 'S':
+			suff *= atof(s);
+			s[len-1] = last;
+			return suff;
+	}
+	s[len-1] = last;
+	return atof(s);
+}
+
+double atofp(char *s)
+/* percent suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(s);
+	last = s[len-1];
+	s[len-1] = '\0';
+	switch (last) {
+		case '%':
+			suff *= 0.01;
+			suff *= atof(s);
+			s[len-1] = last;
+			return suff;
+	}
+	s[len-1] = last;
+	return atof(s);
+}
+
+int nearest_gain(rtlsdr_dev_t *dev, int target_gain)
+{
+	int i, r, err1, err2, count, nearest;
+	int* gains;
+	r = rtlsdr_set_tuner_gain_mode(dev, 1);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
+		return r;
+	}
+	count = rtlsdr_get_tuner_gains(dev, NULL);
+	if (count <= 0) {
+		return 0;
+	}
+	gains = malloc(sizeof(int) * count);
+	count = rtlsdr_get_tuner_gains(dev, gains);
+	nearest = gains[0];
+	for (i=0; i<count; i++) {
+		err1 = abs(target_gain - nearest);
+		err2 = abs(target_gain - gains[i]);
+		if (err2 < err1) {
+			nearest = gains[i];
+		}
+	}
+	free(gains);
+	return nearest;
+}
+
+int verbose_set_frequency(rtlsdr_dev_t *dev, uint32_t frequency)
+{
+	int r;
+	r = rtlsdr_set_center_freq(dev, frequency);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set center freq.\n");
+	} else {
+		fprintf(stderr, "Tuned to %u Hz.\n", frequency);
+	}
+	return r;
+}
+
+int verbose_set_sample_rate(rtlsdr_dev_t *dev, uint32_t samp_rate)
+{
+	int r;
+	r = rtlsdr_set_sample_rate(dev, samp_rate);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set sample rate.\n");
+	} else {
+		fprintf(stderr, "Sampling at %u S/s.\n", samp_rate);
+	}
+	return r;
+}
+
+int verbose_direct_sampling(rtlsdr_dev_t *dev, int on)
+{
+	int r;
+	r = rtlsdr_set_direct_sampling(dev, on);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set direct sampling mode.\n");
+		return r;
+	}
+	if (on == 0) {
+		fprintf(stderr, "Direct sampling mode disabled.\n");}
+	if (on == 1) {
+		fprintf(stderr, "Enabled direct sampling mode, input 1/I.\n");}
+	if (on == 2) {
+		fprintf(stderr, "Enabled direct sampling mode, input 2/Q.\n");}
+	return r;
+}
+
+int verbose_offset_tuning(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_set_offset_tuning(dev, 1);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set offset tuning.\n");
+	} else {
+		fprintf(stderr, "Offset tuning mode enabled.\n");
+	}
+	return r;
+}
+
+int verbose_auto_gain(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_set_tuner_gain_mode(dev, 0);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
+	} else {
+		fprintf(stderr, "Tuner gain set to automatic.\n");
+	}
+	return r;
+}
+
+int verbose_gain_set(rtlsdr_dev_t *dev, int gain)
+{
+	int r;
+	r = rtlsdr_set_tuner_gain_mode(dev, 1);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
+		return r;
+	}
+	r = rtlsdr_set_tuner_gain(dev, gain);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
+	} else {
+		fprintf(stderr, "Tuner gain set to %0.2f dB.\n", gain/10.0);
+	}
+	return r;
+}
+
+int verbose_ppm_set(rtlsdr_dev_t *dev, int ppm_error)
+{
+	int r;
+	if (ppm_error == 0) {
+		return 0;}
+	r = rtlsdr_set_freq_correction(dev, ppm_error);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set ppm error.\n");
+	} else {
+		fprintf(stderr, "Tuner error set to %i ppm.\n", ppm_error);
+	}
+	return r;
+}
+
+int verbose_reset_buffer(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_reset_buffer(dev);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to reset buffers.\n");}
+	return r;
+}
+
+int verbose_device_search(char *s)
+{
+	int i, device_count, device, offset;
+	char *s2;
+	char vendor[256], product[256], serial[256];
+	device_count = rtlsdr_get_device_count();
+	if (!device_count) {
+		fprintf(stderr, "No supported devices found.\n");
+		return -1;
+	}
+	fprintf(stderr, "Found %d device(s):\n", device_count);
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		fprintf(stderr, "  %d:  %s, %s, SN: %s\n", i, vendor, product, serial);
+	}
+	fprintf(stderr, "\n");
+	/* does string look like raw id number */
+	device = (int)strtol(s, &s2, 0);
+	if (s2[0] == '\0' && device >= 0 && device < device_count) {
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	/* does string exact match a serial */
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		if (strcmp(s, serial) != 0) {
+			continue;}
+		device = i;
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	/* does string prefix match a serial */
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		if (strncmp(s, serial, strlen(s)) != 0) {
+			continue;}
+		device = i;
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	/* does string suffix match a serial */
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		offset = strlen(serial) - strlen(s);
+		if (offset < 0) {
+			continue;}
+		if (strncmp(s, serial+offset, strlen(s)) != 0) {
+			continue;}
+		device = i;
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	fprintf(stderr, "No matching devices found.\n");
+	return -1;
+}
+
+// vim: tabstop=8:softtabstop=8:shiftwidth=8:noexpandtab
diff --git a/convenience/convenience.h b/convenience/convenience.h
new file mode 100644
index 0000000..1faa2af
--- /dev/null
+++ b/convenience/convenience.h
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2014 by Kyle Keen <keenerd@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 2 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/>.
+ */
+
+/* a collection of user friendly tools */
+
+/*!
+ * Convert standard suffixes (k, M, G) to double
+ *
+ * \param s a string to be parsed
+ * \return double
+ */
+
+double atofs(char *s);
+
+/*!
+ * Convert time suffixes (s, m, h) to double
+ *
+ * \param s a string to be parsed
+ * \return seconds as double
+ */
+
+double atoft(char *s);
+
+/*!
+ * Convert percent suffixe (%) to double
+ *
+ * \param s a string to be parsed
+ * \return double
+ */
+
+double atofp(char *s);
+
+/*!
+ * Find nearest supported gain
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param target_gain in tenths of a dB
+ * \return 0 on success
+ */
+
+int nearest_gain(rtlsdr_dev_t *dev, int target_gain);
+
+/*!
+ * Set device frequency and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param frequency in Hz
+ * \return 0 on success
+ */
+
+int verbose_set_frequency(rtlsdr_dev_t *dev, uint32_t frequency);
+
+/*!
+ * Set device sample rate and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param samp_rate in samples/second
+ * \return 0 on success
+ */
+
+int verbose_set_sample_rate(rtlsdr_dev_t *dev, uint32_t samp_rate);
+
+/*!
+ * Enable or disable the direct sampling mode and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param on 0 means disabled, 1 I-ADC input enabled, 2 Q-ADC input enabled
+ * \return 0 on success
+ */
+
+int verbose_direct_sampling(rtlsdr_dev_t *dev, int on);
+
+/*!
+ * Enable offset tuning and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on success
+ */
+
+int verbose_offset_tuning(rtlsdr_dev_t *dev);
+
+/*!
+ * Enable auto gain and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on success
+ */
+
+int verbose_auto_gain(rtlsdr_dev_t *dev);
+
+/*!
+ * Set tuner gain and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param gain in tenths of a dB
+ * \return 0 on success
+ */
+
+int verbose_gain_set(rtlsdr_dev_t *dev, int gain);
+
+/*!
+ * Set the frequency correction value for the device and report status on stderr.
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param ppm_error correction value in parts per million (ppm)
+ * \return 0 on success
+ */
+
+int verbose_ppm_set(rtlsdr_dev_t *dev, int ppm_error);
+
+/*!
+ * Reset buffer
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on success
+ */
+
+int verbose_reset_buffer(rtlsdr_dev_t *dev);
+
+/*!
+ * Find the closest matching device.
+ *
+ * \param s a string to be parsed
+ * \return dev_index int, -1 on error
+ */
+
+int verbose_device_search(char *s);
+