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#include <string.h>
#include <assert.h>
#include "sample-util.h"
struct pa_sample_spec default_sample_spec = {
.format = PA_SAMPLE_S16NE,
.rate = 44100,
.channels = 2
};
struct memblock *silence_memblock(struct memblock* b, struct pa_sample_spec *spec) {
assert(b && b->data && spec);
memblock_assert_exclusive(b);
silence_memory(b->data, b->length, spec);
return b;
}
void silence_memchunk(struct memchunk *c, struct pa_sample_spec *spec) {
assert(c && c->memblock && c->memblock->data && spec && c->length);
memblock_assert_exclusive(c->memblock);
silence_memory(c->memblock->data+c->index, c->length, spec);
}
void silence_memory(void *p, size_t length, struct pa_sample_spec *spec) {
char c = 0;
assert(p && length && spec);
switch (spec->format) {
case PA_SAMPLE_U8:
c = 127;
break;
case PA_SAMPLE_S16LE:
case PA_SAMPLE_S16BE:
case PA_SAMPLE_FLOAT32:
c = 0;
break;
case PA_SAMPLE_ALAW:
case PA_SAMPLE_ULAW:
c = 80;
break;
default:
assert(0);
}
memset(p, c, length);
}
size_t mix_chunks(struct mix_info channels[], unsigned nchannels, void *data, size_t length, struct pa_sample_spec *spec, uint8_t volume) {
unsigned c, d;
assert(channels && data && length && spec);
assert(spec->format == PA_SAMPLE_S16NE);
for (d = 0;; d += sizeof(int16_t)) {
int32_t sum = 0;
if (d >= length)
return d;
for (c = 0; c < nchannels; c++) {
int32_t v;
uint8_t volume = channels[c].volume;
if (d >= channels[c].chunk.length)
return d;
if (volume == 0)
v = 0;
else {
v = *((int16_t*) (channels[c].chunk.memblock->data + channels[c].chunk.index + d));
if (volume != 0xFF)
v = v*volume/0xFF;
}
sum += v;
}
if (volume == 0)
sum = 0;
else if (volume != 0xFF)
sum = sum*volume/0xFF;
if (sum < -0x8000) sum = -0x8000;
if (sum > 0x7FFF) sum = 0x7FFF;
*((int16_t*) data) = sum;
data += sizeof(int16_t);
}
}
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