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/*

 * libmad - MPEG audio decoder library

 * Copyright (C) 2000-2004 Underbit Technologies, Inc.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * $Id: decoder.c,v 1.22 2004/01/23 09:41:32 rob Exp $

 */

# ifdef HAVE_CONFIG_H

#  include "config.h"

# endif

# include "global.h"

# ifdef HAVE_SYS_TYPES_H

#  include <sys/types.h>

# endif

# ifdef HAVE_SYS_WAIT_H

#  include <sys/wait.h>

# endif

# ifdef HAVE_UNISTD_H

#  include <unistd.h>

# endif

# ifdef HAVE_FCNTL_H

#  include <fcntl.h>

# endif

# ifdef HAVE_ERRNO_H

#  include <errno.h>

# endif

# include "stream.h"

# include "frame.h"

# include "synth.h"

# include "decoder.h"

/*

 * NAME:	decoder->init()

 * DESCRIPTION:	initialize a decoder object with callback routines

 */

void mad_decoder_init(struct mad_decoder *decoder, void *data,

		      enum mad_flow (*input_func)(void *,

						  struct mad_stream *),

		      enum mad_flow (*header_func)(void *,

						   struct mad_header const *),

		      enum mad_flow (*filter_func)(void *,

						   struct mad_stream const *,

						   struct mad_frame *),

		      enum mad_flow (*output_func)(void *,

						   struct mad_header const *,

						   struct mad_pcm *),

		      enum mad_flow (*error_func)(void *,

						  struct mad_stream *,

						  struct mad_frame *),

		      enum mad_flow (*message_func)(void *,

						    void *, unsigned int *))

{

  decoder->mode         = -1;

  decoder->options      = 0;

  decoder->async.pid    = 0;

  decoder->async.in     = -1;

  decoder->async.out    = -1;

  decoder->sync         = 0;

  decoder->cb_data      = data;

  decoder->input_func   = input_func;

  decoder->header_func  = header_func;

  decoder->filter_func  = filter_func;

  decoder->output_func  = output_func;

  decoder->error_func   = error_func;

  decoder->message_func = message_func;

}

int mad_decoder_finish(struct mad_decoder *decoder)

{

# if defined(USE_ASYNC)

  if (decoder->mode == MAD_DECODER_MODE_ASYNC && decoder->async.pid) {

    pid_t pid;

    int status;

    close(decoder->async.in);

    do

      pid = waitpid(decoder->async.pid, &status, 0);

    while (pid == -1 && errno == EINTR);

    decoder->mode = -1;

    close(decoder->async.out);

    decoder->async.pid = 0;

    decoder->async.in  = -1;

    decoder->async.out = -1;

    if (pid == -1)

      return -1;

    return (!WIFEXITED(status) || WEXITSTATUS(status)) ? -1 : 0;

  }

# endif

  return 0;

}

# if defined(USE_ASYNC)

static

enum mad_flow send_io(int fd, void const *data, size_t len)

{

  char const *ptr = data;

  ssize_t count;

  while (len) {

    do

      count = write(fd, ptr, len);

    while (count == -1 && errno == EINTR);

    if (count == -1)

      return MAD_FLOW_BREAK;

    len -= count;

    ptr += count;

  }

  return MAD_FLOW_CONTINUE;

}

static

enum mad_flow receive_io(int fd, void *buffer, size_t len)

{

  char *ptr = buffer;

  ssize_t count;

  while (len) {

    do

      count = read(fd, ptr, len);

    while (count == -1 && errno == EINTR);

    if (count == -1)

      return (errno == EAGAIN) ? MAD_FLOW_IGNORE : MAD_FLOW_BREAK;

    else if (count == 0)

      return MAD_FLOW_STOP;

    len -= count;

    ptr += count;

  }

  return MAD_FLOW_CONTINUE;

}

static

enum mad_flow receive_io_blocking(int fd, void *buffer, size_t len)

{

  int flags, blocking;

  enum mad_flow result;

  flags = fcntl(fd, F_GETFL);

  if (flags == -1)

    return MAD_FLOW_BREAK;

  blocking = flags & ~O_NONBLOCK;

  if (blocking != flags &&

      fcntl(fd, F_SETFL, blocking) == -1)

    return MAD_FLOW_BREAK;

  result = receive_io(fd, buffer, len);

  if (flags != blocking &&

      fcntl(fd, F_SETFL, flags) == -1)

    return MAD_FLOW_BREAK;

  return result;

}

static

enum mad_flow send(int fd, void const *message, unsigned int size)

{

  enum mad_flow result;

  /* send size */

  result = send_io(fd, &size, sizeof(size));

  /* send message */

  if (result == MAD_FLOW_CONTINUE)

    result = send_io(fd, message, size);

  return result;

}

static

enum mad_flow receive(int fd, void **message, unsigned int *size)

{

  enum mad_flow result;

  unsigned int actual;

  if (*message == 0)

    *size = 0;

  /* receive size */

  result = receive_io(fd, &actual, sizeof(actual));

  /* receive message */

  if (result == MAD_FLOW_CONTINUE) {

    if (actual > *size)

      actual -= *size;

    else {

      *size  = actual;

      actual = 0;

    }

    if (*size > 0) {

      if (*message == 0) {

	*message = malloc(*size);

	if (*message == 0)

	  return MAD_FLOW_BREAK;

      }

      result = receive_io_blocking(fd, *message, *size);

    }

    /* throw away remainder of message */

    while (actual && result == MAD_FLOW_CONTINUE) {

      char sink[256];

      unsigned int len;

      len = actual > sizeof(sink) ? sizeof(sink) : actual;

      result = receive_io_blocking(fd, sink, len);

      actual -= len;

    }

  }

  return result;

}

static

enum mad_flow check_message(struct mad_decoder *decoder)

{

  enum mad_flow result;

  void *message = 0;

  unsigned int size;

  result = receive(decoder->async.in, &message, &size);

  if (result == MAD_FLOW_CONTINUE) {

    if (decoder->message_func == 0)

      size = 0;

    else {

      result = decoder->message_func(decoder->cb_data, message, &size);

      if (result == MAD_FLOW_IGNORE ||

	  result == MAD_FLOW_BREAK)

	size = 0;

    }

    if (send(decoder->async.out, message, size) != MAD_FLOW_CONTINUE)

      result = MAD_FLOW_BREAK;

  }

  if (message)

    free(message);

  return result;

}

# endif

static

enum mad_flow error_default(void *data, struct mad_stream *stream,

			    struct mad_frame *frame)

{

  int *bad_last_frame = data;

  switch (stream->error) {

  case MAD_ERROR_BADCRC:

    if (*bad_last_frame)

      mad_frame_mute(frame);

    else

      *bad_last_frame = 1;

    return MAD_FLOW_IGNORE;

  default:

    return MAD_FLOW_CONTINUE;

  }

}

static

int run_sync(struct mad_decoder *decoder)

{

  enum mad_flow (*error_func)(void *, struct mad_stream *, struct mad_frame *);

  void *error_data;

  int bad_last_frame = 0;

  struct mad_stream *stream;

  struct mad_frame *frame;

  struct mad_synth *synth;

  int result = 0;

  if (decoder->input_func == 0)

    return 0;

  if (decoder->error_func) {

    error_func = decoder->error_func;

    error_data = decoder->cb_data;

  }

  else {

    error_func = error_default;

    error_data = &bad_last_frame;

  }

  stream = &decoder->sync->stream;

  frame  = &decoder->sync->frame;

  synth  = &decoder->sync->synth;

  mad_stream_init(stream);

  mad_frame_init(frame);

  mad_synth_init(synth);

  mad_stream_options(stream, decoder->options);

  do {

    switch (decoder->input_func(decoder->cb_data, stream)) {

    case MAD_FLOW_STOP:

      goto done;

    case MAD_FLOW_BREAK:

      goto fail;

    case MAD_FLOW_IGNORE:

      continue;

    case MAD_FLOW_CONTINUE:

      break;

    }

    while (1) {

# if defined(USE_ASYNC)

      if (decoder->mode == MAD_DECODER_MODE_ASYNC) {

	switch (check_message(decoder)) {

	case MAD_FLOW_IGNORE:

	case MAD_FLOW_CONTINUE:

	  break;

	case MAD_FLOW_BREAK:

	  goto fail;

	case MAD_FLOW_STOP:

	  goto done;

	}

      }

# endif

      if (decoder->header_func) {

	if (mad_header_decode(&frame->header, stream) == -1) {

	  if (!MAD_RECOVERABLE(stream->error))

	    break;

	  switch (error_func(error_data, stream, frame)) {

	  case MAD_FLOW_STOP:

	    goto done;

	  case MAD_FLOW_BREAK:

	    goto fail;

	  case MAD_FLOW_IGNORE:

	  case MAD_FLOW_CONTINUE:

	  default:

	    continue;

	  }

	}

	switch (decoder->header_func(decoder->cb_data, &frame->header)) {

	case MAD_FLOW_STOP:

	  goto done;

	case MAD_FLOW_BREAK:

	  goto fail;

	case MAD_FLOW_IGNORE:

	  continue;

	case MAD_FLOW_CONTINUE:

	  break;

	}

      }

      if (mad_frame_decode(frame, stream) == -1) {

	if (!MAD_RECOVERABLE(stream->error))

	  break;

	switch (error_func(error_data, stream, frame)) {

	case MAD_FLOW_STOP:

	  goto done;

	case MAD_FLOW_BREAK:

	  goto fail;

	case MAD_FLOW_IGNORE:

	  break;

	case MAD_FLOW_CONTINUE:

	default:

	  continue;

	}

      }

      else

	bad_last_frame = 0;

      if (decoder->filter_func) {

	switch (decoder->filter_func(decoder->cb_data, stream, frame)) {

	case MAD_FLOW_STOP:

	  goto done;

	case MAD_FLOW_BREAK:

	  goto fail;

	case MAD_FLOW_IGNORE:

	  continue;

	case MAD_FLOW_CONTINUE:

	  break;

	}

      }

      mad_synth_frame(synth, frame);

      if (decoder->output_func) {

	switch (decoder->output_func(decoder->cb_data,

				     &frame->header, &synth->pcm)) {

	case MAD_FLOW_STOP:

	  goto done;

	case MAD_FLOW_BREAK:

	  goto fail;

	case MAD_FLOW_IGNORE:

	case MAD_FLOW_CONTINUE:

	  break;

	}

      }

    }

  }

  while (stream->error == MAD_ERROR_BUFLEN);

 fail:

  result = -1;

 done:

  mad_synth_finish(synth);

  mad_frame_finish(frame);

  mad_stream_finish(stream);

  return result;

}

# if defined(USE_ASYNC)

static

int run_async(struct mad_decoder *decoder)

{

  pid_t pid;

  int ptoc[2], ctop[2], flags;

  if (pipe(ptoc) == -1)

    return -1;

  if (pipe(ctop) == -1) {

    close(ptoc[0]);

    close(ptoc[1]);

    return -1;

  }

  flags = fcntl(ptoc[0], F_GETFL);

  if (flags == -1 ||

      fcntl(ptoc[0], F_SETFL, flags | O_NONBLOCK) == -1) {

    close(ctop[0]);

    close(ctop[1]);

    close(ptoc[0]);

    close(ptoc[1]);

    return -1;

  }

  pid = fork();

  if (pid == -1) {

    close(ctop[0]);

    close(ctop[1]);

    close(ptoc[0]);

    close(ptoc[1]);

    return -1;

  }

  decoder->async.pid = pid;

  if (pid) {

    /* parent */

    close(ptoc[0]);

    close(ctop[1]);

    decoder->async.in  = ctop[0];

    decoder->async.out = ptoc[1];

    return 0;

  }

  /* child */

  close(ptoc[1]);

  close(ctop[0]);

  decoder->async.in  = ptoc[0];

  decoder->async.out = ctop[1];

  _exit(run_sync(decoder));

  /* not reached */

  return -1;

}

# endif

/*

 * NAME:	decoder->run()

 * DESCRIPTION:	run the decoder thread either synchronously or asynchronously

 */

int mad_decoder_run(struct mad_decoder *decoder, enum mad_decoder_mode mode)

{

  int result;

  int (*run)(struct mad_decoder *) = 0;

  switch (decoder->mode = mode) {

  case MAD_DECODER_MODE_SYNC:

    run = run_sync;

    break;

  case MAD_DECODER_MODE_ASYNC:

# if defined(USE_ASYNC)

    run = run_async;

# endif

    break;

  }

  if (run == 0)

    return -1;

  decoder->sync = malloc(sizeof(*decoder->sync));

  if (decoder->sync == 0)

    return -1;

  result = run(decoder);

  free(decoder->sync);

  decoder->sync = 0;

  return result;

}

/*

 * NAME:	decoder->message()

 * DESCRIPTION:	send a message to and receive a reply from the decoder process

 */

int mad_decoder_message(struct mad_decoder *decoder,

			void *message, unsigned int *len)

{

# if defined(USE_ASYNC)

  if (decoder->mode != MAD_DECODER_MODE_ASYNC ||

      send(decoder->async.out, message, *len) != MAD_FLOW_CONTINUE ||

      receive(decoder->async.in, &message, len) != MAD_FLOW_CONTINUE)

    return -1;

  return 0;

# else

  return -1;

# endif

}