ref: 650a361f5a04e4fc39ade90459d280d227875cb1
dir: /cmixer.c/
/*
** Copyright (c) 2017 rxi
**
** Permission is hereby granted, free of charge, to any person obtaining a copy
** of this software and associated documentation files (the "Software"), to
** deal in the Software without restriction, including without limitation the
** rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
** sell copies of the Software, and to permit persons to whom the Software is
** furnished to do so, subject to the following conditions:
**
** The above copyright notice and this permission notice shall be included in
** all copies or substantial portions of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
** FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
** IN THE SOFTWARE.
**
** Ported to plan 9 on 13mar2021
**/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include "cmixer.h"
static struct {
char *lasterror; /* Last error message */
cm_EventHandler lock; /* Event handler for lock/unlock events */
cm_Source *sources; /* Linked list of active (playing) sources */
cm_Int32 buffer[BUFFER_SIZE]; /* Internal master buffer */
int samplerate; /* Master samplerate */
int gain; /* Master gain (fixed point) */
} cmixer;
static void
dummy_handler(cm_Event *e)
{
USED(e);
}
static void
cm_lock(void)
{
cm_Event e;
e.type = CM_EVENT_LOCK;
cmixer.lock(&e);
}
static void
cm_unlock(void)
{
cm_Event e;
e.type = CM_EVENT_UNLOCK;
cmixer.lock(&e);
}
char*
cm_get_error(void)
{
char *res = cmixer.lasterror;
cmixer.lasterror = nil;
return res;
}
static char*
error(char *msg)
{
cmixer.lasterror = msg;
return msg;
}
void
cm_init(int samplerate)
{
cmixer.samplerate = samplerate;
cmixer.lock = dummy_handler;
cmixer.sources = nil;
cmixer.gain = FX_UNIT;
}
void
cm_set_lock(cm_EventHandler lk)
{
cmixer.lock = lk;
}
void
cm_set_master_gain(double gain)
{
cmixer.gain = FX_FROM_FLOAT(gain);
}
static void
rewind_source(cm_Source *src)
{
cm_Event e;
e.type = CM_EVENT_REWIND;
e.udata = src->udata;
src->handler(&e);
src->position = 0;
src->rewind = 0;
src->end = src->length;
src->nextfill = 0;
}
static void
fill_source_buffer(cm_Source *src, int offset, int length)
{
cm_Event e;
e.type = CM_EVENT_SAMPLES;
e.udata = src->udata;
e.buffer = src->buffer + offset;
e.length = length;
src->handler(&e);
}
static void
process_source(cm_Source *src, int len)
{
int i, n, a, b, p;
int frame, count;
cm_Int32 *dst = cmixer.buffer;
/* Do rewind if flag is set */
if (src->rewind) {
rewind_source(src);
}
/* Don't process if not playing */
if (src->state != CM_STATE_PLAYING) {
return;
}
/* Process audio */
while (len > 0) {
/* Get current position frame */
frame = src->position >> FX_BITS;
/* Fill buffer if required */
if (frame + 3 >= src->nextfill) {
fill_source_buffer(src, (src->nextfill*2) & BUFFER_MASK, BUFFER_SIZE/2);
src->nextfill += BUFFER_SIZE / 4;
}
/* Handle reaching the end of the playthrough */
if (frame >= src->end) {
/* As streams continiously fill the raw buffer in a loop we simply
** increment the end idx by one length and continue reading from it for
** another play-through */
src->end = frame + src->length;
/* Set state and stop processing if we're not set to loop */
if (!src->loop) {
src->state = CM_STATE_STOPPED;
break;
}
}
/* Work out how many frames we should process in the loop */
n = MIN(src->nextfill - 2, src->end) - frame;
count = (n << FX_BITS) / src->rate;
count = MAX(count, 1);
count = MIN(count, len / 2);
len -= count * 2;
/* Add audio to master buffer */
if (src->rate == FX_UNIT) {
/* Add audio to buffer -- basic */
n = frame * 2;
for (i = 0; i < count; i++) {
dst[0] += (src->buffer[(n ) & BUFFER_MASK] * src->lgain) >> FX_BITS;
dst[1] += (src->buffer[(n + 1) & BUFFER_MASK] * src->rgain) >> FX_BITS;
n += 2;
dst += 2;
}
src->position += count * FX_UNIT;
} else {
/* Add audio to buffer -- interpolated */
for (i = 0; i < count; i++) {
n = (src->position >> FX_BITS) * 2;
p = src->position & FX_MASK;
a = src->buffer[(n ) & BUFFER_MASK];
b = src->buffer[(n + 2) & BUFFER_MASK];
dst[0] += (FX_LERP(a, b, p) * src->lgain) >> FX_BITS;
n++;
a = src->buffer[(n ) & BUFFER_MASK];
b = src->buffer[(n + 2) & BUFFER_MASK];
dst[1] += (FX_LERP(a, b, p) * src->rgain) >> FX_BITS;
src->position += src->rate;
dst += 2;
}
}
}
}
void
cm_process(cm_Int16 *dst, int len)
{
int i;
cm_Source **s;
/* Process in chunks of BUFFER_SIZE if `len` is larger than BUFFER_SIZE */
while (len > BUFFER_SIZE) {
cm_process(dst, BUFFER_SIZE);
dst += BUFFER_SIZE;
len -= BUFFER_SIZE;
}
/* Zeroset internal buffer */
memset(cmixer.buffer, 0, len * sizeof(cmixer.buffer[0]));
/* Process active sources */
cm_lock();
s = &cmixer.sources;
while (*s) {
process_source(*s, len);
/* Remove source from list if it is no longer playing */
if ((*s)->state != CM_STATE_PLAYING) {
(*s)->active = 0;
*s = (*s)->next;
} else {
s = &(*s)->next;
}
}
cm_unlock();
/* Copy internal buffer to destination and clip */
for (i = 0; i < len; i++) {
int x = (cmixer.buffer[i] * cmixer.gain) >> FX_BITS;
dst[i] = CLAMP(x, -32768, 32767);
}
}
cm_Source*
cm_new_source(cm_SourceInfo *info)
{
cm_Source *src = calloc(1, sizeof(*src));
if (!src) {
error("allocation failed");
return nil;
}
src->handler = info->handler;
src->length = info->length;
src->samplerate = info->samplerate;
src->udata = info->udata;
cm_set_gain(src, 1);
cm_set_pan(src, 0);
cm_set_pitch(src, 1);
cm_set_loop(src, 0);
cm_stop(src);
return src;
}
static char* wav_init(cm_SourceInfo *info, void *data, int len, int ownsdata);
#ifdef CM_USE_STB_VORBIS
static char* ogg_init(cm_SourceInfo *info, void *data, int len, int ownsdata);
#endif
static int
check_header(void *data, int size, char *str, int offset)
{
int len = strlen(str);
return (size >= offset + len) && !memcmp((char*) data + offset, str, len);
}
static cm_Source*
new_source_from_mem(void *data, int size, int ownsdata)
{
char *err;
cm_SourceInfo info;
if (check_header(data, size, "WAVE", 8)) {
err = wav_init(&info, data, size, ownsdata);
if (err) {
return nil;
}
return cm_new_source(&info);
}
#ifdef CM_USE_STB_VORBIS
if (check_header(data, size, "OggS", 0)) {
err = ogg_init(&info, data, size, ownsdata);
if (err) {
return nil;
}
return cm_new_source(&info);
}
#endif
error("unknown format or invalid data");
return nil;
}
static void*
load_file(char *filename, int *size)
{
Biobuf *fp;
void *data;
int n;
fp = Bopen(filename, OREAD);
if (!fp) {
return nil;
}
/* Get size */
Bseek(fp, 0, 2);
*size = Boffset(fp);
Bseek(fp, 0, 0);
/* Malloc, read and return data */
data = malloc(*size);
if (!data) {
Bterm(fp);
return nil;
}
n = Bread(fp, data, *size);
Bterm(fp);
if (n != *size) {
free(data);
return nil;
}
return data;
}
cm_Source*
cm_new_source_from_file(char *filename)
{
int size;
cm_Source *src;
void *data;
/* Load file into memory */
data = load_file(filename, &size);
if (!data) {
error("could not load file");
return nil;
}
/* Try to load and return */
src = new_source_from_mem(data, size, 1);
if (!src) {
free(data);
return nil;
}
return src;
}
cm_Source*
cm_new_source_from_mem(void *data, int size)
{
return new_source_from_mem(data, size, 0);
}
void
cm_destroy_source(cm_Source *src)
{
cm_Event e;
cm_lock();
if (src->active) {
cm_Source **s = &cmixer.sources;
while (*s) {
if (*s == src) {
*s = src->next;
break;
}
}
}
cm_unlock();
e.type = CM_EVENT_DESTROY;
e.udata = src->udata;
src->handler(&e);
free(src);
}
double
cm_get_length(cm_Source *src)
{
return src->length / (double) src->samplerate;
}
double
cm_get_position(cm_Source *src)
{
return ((src->position >> FX_BITS) % src->length) / (double) src->samplerate;
}
int
cm_get_state(cm_Source *src)
{
return src->state;
}
static void
recalc_source_gains(cm_Source *src)
{
double l, r;
double pan = src->pan;
l = src->gain * (pan <= 0. ? 1. : 1. - pan);
r = src->gain * (pan >= 0. ? 1. : 1. + pan);
src->lgain = FX_FROM_FLOAT(l);
src->rgain = FX_FROM_FLOAT(r);
}
void
cm_set_gain(cm_Source *src, double gain)
{
src->gain = gain;
recalc_source_gains(src);
}
void
cm_set_pan(cm_Source *src, double pan)
{
src->pan = CLAMP(pan, -1.0, 1.0);
recalc_source_gains(src);
}
void
cm_set_pitch(cm_Source *src, double pitch)
{
double rate;
if (pitch > 0.) {
rate = src->samplerate / (double) cmixer.samplerate * pitch;
} else {
rate = 0.001;
}
src->rate = FX_FROM_FLOAT(rate);
}
void
cm_set_loop(cm_Source *src, int loop)
{
src->loop = loop;
}
void
cm_play(cm_Source *src)
{
cm_lock();
src->state = CM_STATE_PLAYING;
if (!src->active) {
src->active = 1;
src->next = cmixer.sources;
cmixer.sources = src;
}
cm_unlock();
}
void
cm_pause(cm_Source *src)
{
src->state = CM_STATE_PAUSED;
}
void
cm_stop(cm_Source *src)
{
src->state = CM_STATE_STOPPED;
src->rewind = 1;
}
/*============================================================================
** Wav stream
**============================================================================*/
typedef struct {
void *data;
int bitdepth;
int samplerate;
int channels;
int length;
} Wav;
typedef struct {
Wav wav;
void *data;
int idx;
} WavStream;
static char*
find_subchunk(char *data, int len, char *id, int *size)
{
/* TODO : Error handling on malformed wav file */
int idlen = strlen(id);
char *p = data + 12;
next:
*size = *((cm_UInt32*) (p + 4));
if (memcmp(p, id, idlen)) {
p += 8 + *size;
if (p > data + len) return nil;
goto next;
}
return p + 8;
}
static char*
read_wav(Wav *w, void *data, int len)
{
int bitdepth, channels, samplerate, format;
int sz;
char *p = data;
memset(w, 0, sizeof(*w));
/* Check header */
if (memcmp(p, "RIFF", 4) || memcmp(p + 8, "WAVE", 4)) {
return error("bad wav header");
}
/* Find fmt subchunk */
p = find_subchunk(data, len, "fmt", &sz);
if (!p) {
return error("no fmt subchunk");
}
/* Load fmt info */
format = *((cm_UInt16*) (p));
channels = *((cm_UInt16*) (p + 2));
samplerate = *((cm_UInt32*) (p + 4));
bitdepth = *((cm_UInt16*) (p + 14));
if (format != 1) {
return error("unsupported format");
}
if (channels == 0 || samplerate == 0 || bitdepth == 0) {
return error("bad format");
}
/* Find data subchunk */
p = find_subchunk(data, len, "data", &sz);
if (!p) {
return error("no data subchunk");
}
/* Init struct */
w->data = (void*) p;
w->samplerate = samplerate;
w->channels = channels;
w->length = (sz / (bitdepth / 8)) / channels;
w->bitdepth = bitdepth;
/* Done */
return nil;
}
#define WAV_PROCESS_LOOP(X) \
while (n--) { \
X \
dst += 2; \
s->idx++; \
}
static void
wav_handler(cm_Event *e)
{
int x, n;
cm_Int16 *dst;
WavStream *s = e->udata;
int len;
switch (e->type) {
case CM_EVENT_DESTROY:
free(s->data);
free(s);
break;
case CM_EVENT_SAMPLES:
dst = e->buffer;
len = e->length / 2;
fill:
n = MIN(len, s->wav.length - s->idx);
len -= n;
if (s->wav.bitdepth == 16 && s->wav.channels == 1) {
WAV_PROCESS_LOOP({
dst[0] = dst[1] = ((cm_Int16*) s->wav.data)[s->idx];
});
} else if (s->wav.bitdepth == 16 && s->wav.channels == 2) {
WAV_PROCESS_LOOP({
x = s->idx * 2;
dst[0] = ((cm_Int16*) s->wav.data)[x ];
dst[1] = ((cm_Int16*) s->wav.data)[x + 1];
});
} else if (s->wav.bitdepth == 8 && s->wav.channels == 1) {
WAV_PROCESS_LOOP({
dst[0] = dst[1] = (((cm_UInt8*) s->wav.data)[s->idx] - 128) << 8;
});
} else if (s->wav.bitdepth == 8 && s->wav.channels == 2) {
WAV_PROCESS_LOOP({
x = s->idx * 2;
dst[0] = (((cm_UInt8*) s->wav.data)[x ] - 128) << 8;
dst[1] = (((cm_UInt8*) s->wav.data)[x + 1] - 128) << 8;
});
}
/* Loop back and continue filling buffer if we didn't fill the buffer */
if (len > 0) {
s->idx = 0;
goto fill;
}
break;
case CM_EVENT_REWIND:
s->idx = 0;
break;
}
}
static char*
wav_init(cm_SourceInfo *info, void *data, int len, int ownsdata)
{
WavStream *stream;
Wav wav;
char *err = read_wav(&wav, data, len);
if (err != nil) {
return err;
}
if (wav.channels > 2 || (wav.bitdepth != 16 && wav.bitdepth != 8)) {
return error("unsupported wav format");
}
stream = calloc(1, sizeof(*stream));
if (!stream) {
return error("allocation failed");
}
stream->wav = wav;
if (ownsdata) {
stream->data = data;
}
stream->idx = 0;
info->udata = stream;
info->handler = wav_handler;
info->samplerate = wav.samplerate;
info->length = wav.length;
/* Return nil (no error) for success */
return nil;
}
/*============================================================================
** Ogg stream
**============================================================================*/
#ifdef CM_USE_STB_VORBIS
#define STB_VORBIS_HEADER_ONLY
#include "stb_vorbis.c"
typedef struct {
stb_vorbis *ogg;
void *data;
} OggStream;
static void
ogg_handler(cm_Event *e)
{
int n, len;
OggStream *s = e->udata;
cm_Int16 *buf;
switch (e->type) {
case CM_EVENT_DESTROY:
stb_vorbis_close(s->ogg);
free(s->data);
free(s);
break;
case CM_EVENT_SAMPLES:
len = e->length;
buf = e->buffer;
fill:
n = stb_vorbis_get_samples_short_interleaved(s->ogg, 2, buf, len);
n *= 2;
/* rewind and fill remaining buffer if we reached the end of the ogg
** before filling it */
if (len != n) {
stb_vorbis_seek_start(s->ogg);
buf += n;
len -= n;
goto fill;
}
break;
case CM_EVENT_REWIND:
stb_vorbis_seek_start(s->ogg);
break;
}
}
static char*
ogg_init(cm_SourceInfo *info, void *data, int len, int ownsdata)
{
OggStream *stream;
stb_vorbis *ogg;
stb_vorbis_info ogginfo;
int err;
ogg = stb_vorbis_open_memory(data, len, &err, nil);
if (!ogg) {
return error("invalid ogg data");
}
stream = calloc(1, sizeof(*stream));
if (!stream) {
stb_vorbis_close(ogg);
return error("allocation failed");
}
stream->ogg = ogg;
if (ownsdata) {
stream->data = data;
}
ogginfo = stb_vorbis_get_info(ogg);
info->udata = stream;
info->handler = ogg_handler;
info->samplerate = ogginfo.sample_rate;
info->length = stb_vorbis_stream_length_in_samples(ogg);
/* Return nil (no error) for success */
return nil;
}
#endif