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add new API function pa_memchunk_sine()

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Ease generation of sine signals. Try to make the repeatable sine
memblock fit into a single mempool slot.
This commit is contained in:
Lennart Poettering 2009-01-12 19:48:44 +01:00
parent 949de8156e
commit b8e6aae08e
2 changed files with 36 additions and 0 deletions
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34
src/pulsecore/sample-util.c
View file

@ -39,6 +39,7 @@
#include <pulsecore/core-error.h>
#include <pulsecore/macro.h>
#include <pulsecore/g711.h>
#include <pulsecore/core-util.h>
#include "sample-util.h"
#include "endianmacros.h"
@ -1015,3 +1016,36 @@ void pa_memchunk_dump_to_file(pa_memchunk *c, const char *fn) {
fclose(f);
}
static void calc_sine(float *f, size_t l, double freq) {
size_t i;
l /= sizeof(float);
for (i = 0; i < l; i++)
*(f++) = (float) 0.5f * sin((double) i*M_PI*2*freq / (double) l);
}
void pa_memchunk_sine(pa_memchunk *c, pa_mempool *pool, unsigned rate, unsigned freq) {
size_t l;
unsigned gcd, n;
void *p;
pa_memchunk_reset(c);
gcd = pa_gcd(rate, freq);
n = rate / gcd;
l = pa_mempool_block_size_max(pool) / sizeof(float);
l /= n;
if (l <= 0) l = 1;
l *= n;
c->length = l * sizeof(float);
c->memblock = pa_memblock_new(pool, c->length);
p = pa_memblock_acquire(c->memblock);
calc_sine(p, c->length, freq * l / rate);
pa_memblock_release(c->memblock);
}

2
src/pulsecore/sample-util.h
View file

@ -83,4 +83,6 @@ size_t pa_usec_to_bytes_round_up(pa_usec_t t, const pa_sample_spec *spec);
void pa_memchunk_dump_to_file(pa_memchunk *c, const char *fn);
void pa_memchunk_sine(pa_memchunk *c, pa_mempool *pool, unsigned rate, unsigned freq);
#endif