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transform/scale: Use a rational rather than floating point factor.

This commit is contained in:
Martin Ling 2015-09-09 23:39:15 +01:00 committed by Uwe Hermann
parent 85aa1b599f
commit 2d237f3ce8
1 changed files with 10 additions and 4 deletions
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14
src/transform/scale.c
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@ -26,7 +26,7 @@
#define LOG_PREFIX "transform/scale"
struct context {
double factor;
struct sr_rational factor;
};
static int init(struct sr_transform *t, GHashTable *options)
@ -38,7 +38,8 @@ static int init(struct sr_transform *t, GHashTable *options)
t->priv = ctx = g_malloc0(sizeof(struct context));
ctx->factor = g_variant_get_double(g_hash_table_lookup(options, "factor"));
g_variant_get(g_hash_table_lookup(options, "factor"), "(xt)",
&ctx->factor.p, &ctx->factor.q);
return SR_OK;
}
@ -52,6 +53,7 @@ static int receive(const struct sr_transform *t,
struct sr_channel *ch;
GSList *l;
float *fdata;
float factor;
int i, num_channels, c;
if (!t || !t->sdi || !packet_in || !packet_out)
@ -63,12 +65,13 @@ static int receive(const struct sr_transform *t,
analog = packet_in->payload;
fdata = (float *)analog->data;
num_channels = g_slist_length(analog->channels);
factor = (float) ctx->factor.p / ctx->factor.q;
for (i = 0; i < analog->num_samples; i++) {
/* For now scale all values in all channels. */
for (l = analog->channels, c = 0; l; l = l->next, c++) {
ch = l->data;
(void)ch;
fdata[i * num_channels + c] *= ctx->factor;
fdata[i * num_channels + c] *= factor;
}
}
break;
@ -104,9 +107,12 @@ static struct sr_option options[] = {
static const struct sr_option *get_options(void)
{
int64_t p = 1;
uint64_t q = 1;
/* Default to a scaling factor of 1.0. */
if (!options[0].def)
options[0].def = g_variant_ref_sink(g_variant_new_double(1.0));
options[0].def = g_variant_ref_sink(g_variant_new(("(xt"), &p, &q));
return options;
}