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pcm.c
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pcm.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include "pcm.h"
#include "util.h"
#include "sampleconv.h"
struct pcm_state {
int fd;
struct pcm_enc_info *enc_info;
ssize_t pos;
};
struct pcm_enc_info {
const char *name;
int bytes, prec, can_dither;
void (*read_func)(char *, sample_t *, ssize_t);
void (*write_func)(sample_t *, char *, ssize_t);
};
static const char codec_name[] = "pcm";
static struct pcm_enc_info encodings[] = {
{ "s16", 2, 16, 1, read_buf_s16, write_buf_s16 },
{ "u8", 1, 8, 1, read_buf_u8, write_buf_u8 },
{ "s8", 1, 8, 1, read_buf_s8, write_buf_s8 },
{ "s24", 4, 24, 1, read_buf_s24, write_buf_s24 },
{ "s32", 4, 32, 1, read_buf_s32, write_buf_s32 },
{ "float", 4, 24, 0, read_buf_float, write_buf_float },
{ "double", 8, 53, 0, read_buf_double, write_buf_double },
};
static struct pcm_enc_info * pcm_get_enc_info(const char *enc)
{
int i;
if (enc == NULL)
return &encodings[0];
for (i = 0; i < LENGTH(encodings); ++i)
if (strcmp(enc, encodings[i].name) == 0)
return &encodings[i];
return NULL;
}
ssize_t pcm_read(struct codec *c, sample_t *buf, ssize_t frames)
{
ssize_t n;
struct pcm_state *state = (struct pcm_state *) c->data;
n = read(state->fd, buf, frames * c->channels * state->enc_info->bytes);
if (n == -1) {
LOG_FMT(LL_ERROR, "%s: read failed: %s", codec_name, strerror(errno));
return 0;
}
n = n / state->enc_info->bytes / c->channels;
state->enc_info->read_func((char *) buf, buf, n * c->channels);
state->pos += n;
return n;
}
ssize_t pcm_write(struct codec *c, sample_t *buf, ssize_t frames)
{
ssize_t n;
struct pcm_state *state = (struct pcm_state *) c->data;
state->enc_info->write_func(buf, (char *) buf, frames * c->channels);
n = write(state->fd, buf, frames * c->channels * state->enc_info->bytes);
if (n == -1) {
LOG_FMT(LL_ERROR, "%s: write failed: %s", codec_name, strerror(errno));
return 0;
}
n = n / state->enc_info->bytes / c->channels;
state->pos += n;
return n;
}
ssize_t pcm_seek(struct codec *c, ssize_t pos)
{
off_t o;
struct pcm_state *state = (struct pcm_state *) c->data;
if (c->frames == -1)
return -1;
if (pos < 0)
pos = 0;
else if (pos > c->frames)
pos = c->frames;
o = lseek(state->fd, pos * state->enc_info->bytes * c->channels, SEEK_SET);
if (o == -1)
return -1;
state->pos = o;
return o / state->enc_info->bytes / c->channels;
}
ssize_t pcm_delay(struct codec *c)
{
return 0;
}
void pcm_drop(struct codec *c)
{
/* do nothing */
}
void pcm_pause(struct codec *c, int p)
{
/* do nothing */
}
void pcm_destroy(struct codec *c)
{
struct pcm_state *state = (struct pcm_state *) c->data;
close(state->fd);
free(state);
}
struct codec * pcm_codec_init(const char *path, const char *type, const char *enc, int fs, int channels, int endian, int mode)
{
int fd = -1;
off_t size;
struct pcm_enc_info *enc_info;
struct pcm_state *state = NULL;
struct codec *c = NULL;
if ((enc_info = pcm_get_enc_info(enc)) == NULL) {
LOG_FMT(LL_ERROR, "%s: error: bad encoding: %s", codec_name, enc);
goto fail;
}
if (!(endian == CODEC_ENDIAN_DEFAULT || endian == CODEC_ENDIAN_NATIVE)) {
LOG_FMT(LL_ERROR, "%s: error: endian conversion not supported", codec_name);
goto fail;
}
if (strcmp(path, "-") == 0)
fd = (mode == CODEC_MODE_WRITE) ? STDOUT_FILENO : STDIN_FILENO;
else if ((fd = open(path, (mode == CODEC_MODE_WRITE) ? O_WRONLY|O_CREAT|O_TRUNC : O_RDONLY, 0644)) == -1) {
LOG_FMT(LL_OPEN_ERROR, "%s: error: failed to open file: %s: %s", codec_name, path, strerror(errno));
goto fail;
}
state = calloc(1, sizeof(struct pcm_state));
state->fd = fd;
state->enc_info = enc_info;
c = calloc(1, sizeof(struct codec));
c->path = path;
c->type = type;
c->enc = enc_info->name;
c->fs = fs;
c->channels = channels;
c->prec = enc_info->prec;
c->can_dither = enc_info->can_dither;
c->frames = -1;
if (mode == CODEC_MODE_READ) {
size = lseek(fd, 0, SEEK_END);
c->frames = (size == -1) ? -1 : size / enc_info->bytes / channels;
lseek(fd, 0, SEEK_SET);
}
c->read = pcm_read;
c->write = pcm_write;
c->seek = pcm_seek;
c->delay = pcm_delay;
c->drop = pcm_drop;
c->pause = pcm_pause;
c->destroy = pcm_destroy;
c->data = state;
return c;
fail:
return NULL;
}
void pcm_codec_print_encodings(const char *type)
{
int i;
for (i = 0; i < LENGTH(encodings); ++i)
fprintf(stdout, " %s", encodings[i].name);
}