/*
    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 $
*/

#pragma GCC optimize ("O3")

#  include "config.h"

# 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

# include <stdlib.h>

# 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) {
    (void)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;
    stackenter(__FUNCTION__, __FILE__, __LINE__);

    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, decoder->output_func);
            if (decoder->output_func) {
                //  switch (decoder->output_func(decoder->cb_data, &frame->header, &synth->pcm)) {
                switch (mad_synth_frame(synth, frame, decoder->output_func, decoder->cb_data)) { //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
    (void) decoder;
    (void) message;
    (void) len;
    return -1;
# endif
}
