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#include <string.h>
#include <assert.h>
#include "sample.h"
struct sample_spec default_sample_spec = {
.format = SAMPLE_S16NE,
.rate = 44100,
.channels = 2
};
struct memblock *silence(struct memblock* b, struct sample_spec *spec) {
char c = 0;
assert(b && spec);
memblock_assert_exclusive(b);
switch (spec->format) {
case SAMPLE_U8:
c = 127;
break;
case SAMPLE_S16LE:
case SAMPLE_S16BE:
case SAMPLE_FLOAT32:
c = 0;
break;
case SAMPLE_ALAW:
case SAMPLE_ULAW:
c = 80;
break;
}
memset(b->data, c, b->length);
return b;
}
void add_clip(struct memchunk *target, struct memchunk *chunk, struct sample_spec *spec) {
int16_t *p, *d;
size_t i;
assert(target && target->memblock && chunk && chunk->memblock && spec);
assert(spec->format == SAMPLE_S16NE);
assert((target->length & 1) == 0);
d = target->memblock->data + target->index;
p = chunk->memblock->data + chunk->index;
for (i = 0; i < target->length && i < chunk->length; i++) {
int32_t r = (int32_t) *d + (int32_t) *p;
if (r < -0x8000) r = 0x8000;
if (r > 0x7FFF) r = 0x7FFF;
*d = (int16_t) r;
}
}
size_t sample_size(struct sample_spec *spec) {
assert(spec);
size_t b = 1;
switch (spec->format) {
case SAMPLE_U8:
case SAMPLE_ULAW:
case SAMPLE_ALAW:
b = 1;
break;
case SAMPLE_S16LE:
case SAMPLE_S16BE:
b = 2;
break;
case SAMPLE_FLOAT32:
b = 4;
break;
}
return b * spec->channels;
}
size_t bytes_per_second(struct sample_spec *spec) {
assert(spec);
return spec->rate*sample_size(spec);
}
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