gstreamer/sys/oss/oss_probe.c

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C
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#include <sys/soundcard.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <glib.h>
typedef struct _Probe Probe;
struct _Probe
{
int fd;
int format;
int n_channels;
GArray *rates;
int min;
int max;
};
typedef struct _Range Range;
struct _Range
{
int min;
int max;
};
static gboolean probe_check (Probe * probe);
static int check_rate (Probe * probe, int irate);
static void add_range (GQueue * queue, int min, int max);
static void add_rate (GArray * array, int rate);
static int int_compare (gconstpointer a, gconstpointer b);
int
main (int argc, char *argv[])
{
int fd;
int i;
Probe *probe;
fd = open ("/dev/dsp", O_RDWR);
if (fd < 0) {
perror ("/dev/dsp");
exit (1);
}
probe = g_new0 (Probe, 1);
probe->fd = fd;
probe->format = AFMT_S16_LE;
probe->n_channels = 2;
probe_check (probe);
g_array_sort (probe->rates, int_compare);
for (i = 0; i < probe->rates->len; i++) {
g_print ("%d\n", g_array_index (probe->rates, int, i));
}
g_array_free (probe->rates, TRUE);
g_free (probe);
#if 0
probe = g_new0 (Probe, 1);
probe->fd = fd;
probe->format = AFMT_S16_LE;
probe->n_channels = 1;
probe_check (probe);
for (i = 0; i < probe->rates->len; i++) {
g_print ("%d\n", g_array_index (probe->rates, int, i));
}
probe = g_new0 (Probe, 1);
probe->fd = fd;
probe->format = AFMT_U8;
probe->n_channels = 2;
probe_check (probe);
for (i = 0; i < probe->rates->len; i++) {
g_print ("%d\n", g_array_index (probe->rates, int, i));
}
probe = g_new0 (Probe, 1);
probe->fd = fd;
probe->format = AFMT_U8;
probe->n_channels = 1;
probe_check (probe);
for (i = 0; i < probe->rates->len; i++) {
g_print ("%d\n", g_array_index (probe->rates, int, i));
}
#endif
return 0;
}
static gboolean
probe_check (Probe * probe)
{
Range *range;
GQueue *ranges;
int exact_rates = 0;
gboolean checking_exact_rates = TRUE;
int n_checks = 0;
gboolean result = TRUE;
ranges = g_queue_new ();
probe->rates = g_array_new (FALSE, FALSE, sizeof (int));
probe->min = check_rate (probe, 1000);
n_checks++;
probe->max = check_rate (probe, 100000);
n_checks++;
add_range (ranges, probe->min + 1, probe->max - 1);
while ((range = g_queue_pop_head (ranges))) {
int min1;
int max1;
int mid;
int mid_ret;
g_print ("checking [%d,%d]\n", range->min, range->max);
mid = (range->min + range->max) / 2;
mid_ret = check_rate (probe, mid);
n_checks++;
if (mid == mid_ret && checking_exact_rates) {
int max_exact_matches = 100;
exact_rates++;
if (exact_rates > max_exact_matches) {
g_print ("got %d exact rates, assuming all are exact\n",
max_exact_matches);
result = FALSE;
g_free (range);
break;
}
} else {
checking_exact_rates = FALSE;
}
/* Assume that the rate is arithmetically rounded to the nearest
* supported rate. */
if (mid == mid_ret) {
min1 = mid - 1;
max1 = mid + 1;
} else {
if (mid < mid_ret) {
min1 = mid - (mid_ret - mid);
max1 = mid_ret + 1;
} else {
min1 = mid_ret - 1;
max1 = mid + (mid - mid_ret);
}
}
add_range (ranges, range->min, min1);
add_range (ranges, max1, range->max);
g_free (range);
}
while ((range = g_queue_pop_head (ranges))) {
g_free (range);
}
g_queue_free (ranges);
return result;
}
static void
add_range (GQueue * queue, int min, int max)
{
g_print ("trying to add [%d,%d]\n", min, max);
if (min <= max) {
Range *range = g_new0 (Range, 1);
range->min = min;
range->max = max;
g_queue_push_tail (queue, range);
//g_queue_push_head (queue, range);
}
}
static int
check_rate (Probe * probe, int irate)
{
int rate;
int format;
int n_channels;
rate = irate;
format = probe->format;
n_channels = probe->n_channels;
ioctl (probe->fd, SNDCTL_DSP_SETFMT, &format);
ioctl (probe->fd, SNDCTL_DSP_CHANNELS, &n_channels);
ioctl (probe->fd, SNDCTL_DSP_SPEED, &rate);
g_print ("rate %d -> %d\n", irate, rate);
if (rate == irate - 1 || rate == irate + 1) {
rate = irate;
}
add_rate (probe->rates, rate);
return rate;
}
static void
add_rate (GArray * array, int rate)
{
int i;
int val;
for (i = 0; i < array->len; i++) {
val = g_array_index (array, int, i);
if (val == rate)
return;
}
g_print ("supported rate: %d\n", rate);
g_array_append_val (array, rate);
}
static int
int_compare (gconstpointer a, gconstpointer b)
{
const int *va = (const int *) a;
const int *vb = (const int *) b;
if (*va < *vb)
return -1;
if (*va > *vb)
return 1;
return 0;
}