stream.c

video linux conference

{
    stream_sys_t *p_sys = s->p_sys;
    stream_track_t *tk = &p_sys->stream.tk[p_sys->stream.i_tk];
    int64_t i_off;

    if( tk->i_start >= tk->i_end ) return 0; /* EOF */

#if 0
    msg_Dbg( s, "AStreamPeekStream: %d pos="I64Fd" tk=%d "
             "start="I64Fd" offset=%d end="I64Fd,
             i_read, p_sys->i_pos, p_sys->stream.i_tk,
             tk->i_start, p_sys->stream.i_offset, tk->i_end );
#endif

    /* Avoid problem, but that should *never* happen */
    if( i_read > STREAM_CACHE_TRACK_SIZE / 2 )
        i_read = STREAM_CACHE_TRACK_SIZE / 2;

    while( tk->i_end - tk->i_start - p_sys->stream.i_offset < i_read )
    {
        if( p_sys->stream.i_used <= 1 )
        {
            /* Be sure we will read something */
            p_sys->stream.i_used += i_read -
                (tk->i_end - tk->i_start - p_sys->stream.i_offset);
        }
        if( AStreamRefillStream( s ) ) break;
    }

    if( tk->i_end - tk->i_start - p_sys->stream.i_offset < i_read )
        i_read = tk->i_end - tk->i_start - p_sys->stream.i_offset;

    /* Now, direct pointer or a copy ? */
    i_off = (tk->i_start + p_sys->stream.i_offset) % STREAM_CACHE_TRACK_SIZE;
    if( i_off + i_read <= STREAM_CACHE_TRACK_SIZE )
    {
        *pp_peek = &tk->p_buffer[i_off];
        return i_read;
    }

    if( p_sys->i_peek < i_read )
    {
        p_sys->p_peek = realloc( p_sys->p_peek, i_read );
        if( !p_sys->p_peek )
        {
            p_sys->i_peek = 0;
            return 0;
        }
        p_sys->i_peek = i_read;
    }

    memcpy( p_sys->p_peek, &tk->p_buffer[i_off],
            STREAM_CACHE_TRACK_SIZE - i_off );
    memcpy( &p_sys->p_peek[STREAM_CACHE_TRACK_SIZE - i_off],
            &tk->p_buffer[0], i_read - (STREAM_CACHE_TRACK_SIZE - i_off) );

    *pp_peek = p_sys->p_peek;
    return i_read;
}

static int AStreamSeekStream( stream_t *s, int64_t i_pos )
{
    stream_sys_t *p_sys = s->p_sys;
    access_t     *p_access = p_sys->p_access;
    vlc_bool_t   b_aseek;
    vlc_bool_t   b_afastseek;
    int i_maxth;
    int i_new;
    int i;

#if 0
    msg_Dbg( s, "AStreamSeekStream: to "I64Fd" pos="I64Fd
             "tk=%d start="I64Fd" offset=%d end="I64Fd,
             i_pos, p_sys->i_pos, p_sys->stream.i_tk,
             p_sys->stream.tk[p_sys->stream.i_tk].i_start,
             p_sys->stream.i_offset,
             p_sys->stream.tk[p_sys->stream.i_tk].i_end );
#endif


    /* Seek in our current track ? */
    if( i_pos >= p_sys->stream.tk[p_sys->stream.i_tk].i_start &&
        i_pos < p_sys->stream.tk[p_sys->stream.i_tk].i_end )
    {
        //msg_Dbg( s, "AStreamSeekStream: current track" );
        p_sys->i_pos = i_pos;
        p_sys->stream.i_offset = i_pos - p_sys->stream.tk[p_sys->stream.i_tk].i_start;
        return VLC_SUCCESS;
    }

    access2_Control( p_access, ACCESS_CAN_SEEK, &b_aseek );
    if( !b_aseek )
    {
        /* We can't do nothing */
        msg_Dbg( s, "AStreamSeekStream: can't seek" );
        return VLC_EGENERIC;
    }

    /* Date the current track */
    p_sys->stream.tk[p_sys->stream.i_tk].i_date = mdate();

    /* Try to reuse already read data */
    for( i = 0; i < STREAM_CACHE_TRACK; i++ )
    {
        stream_track_t *tk = &p_sys->stream.tk[i];

        if( i_pos >= tk->i_start && i_pos <= tk->i_end )
        {
#if 0
            msg_Dbg( s, "AStreamSeekStream: reusing %d start="I64Fd
                     " end="I64Fd, i, tk->i_start, tk->i_end );
#endif
            /* Seek at the end of the buffer */
            if( ASeek( s, tk->i_end ) ) return VLC_EGENERIC;

            /* That's it */
            p_sys->i_pos = i_pos;
            p_sys->stream.i_tk = i;
            p_sys->stream.i_offset = i_pos - tk->i_start;

            if( p_sys->stream.i_used < 1024 )
                p_sys->stream.i_used = 1024;

            if( AStreamRefillStream( s ) && i_pos == tk->i_end )
                return VLC_EGENERIC;

            return VLC_SUCCESS;
        }
    }

    access2_Control( p_access, ACCESS_CAN_SEEK, &b_afastseek );
    /* FIXME compute seek cost (instead of static 'stupid' value) */
    i_maxth = __MIN( p_sys->stream.i_read_size, STREAM_READ_ATONCE / 2 );
    if( !b_afastseek )
        i_maxth *= 3;

    /* FIXME TODO */
#if 0
    /* Search closest segment TODO */
    for( i = 0; i < STREAM_CACHE_TRACK; i++ )
    {
        stream_track_t *tk = &p_sys->stream.tk[i];

        if( i_pos + i_maxth >= tk->i_start )
        {
            msg_Dbg( s, "good segment before current pos, TODO" );
        }
        if( i_pos - i_maxth <= tk->i_end )
        {
            msg_Dbg( s, "good segment after current pos, TODO" );
        }
    }
#endif

    /* Nothing good, seek and choose oldest segment */
    if( ASeek( s, i_pos ) ) return VLC_EGENERIC;
    p_sys->i_pos = i_pos;

    i_new = 0;
    for( i = 1; i < STREAM_CACHE_TRACK; i++ )
    {
        if( p_sys->stream.tk[i].i_date < p_sys->stream.tk[i_new].i_date )
            i_new = i;
    }

    /* Reset the segment */
    p_sys->stream.i_tk     = i_new;
    p_sys->stream.i_offset =  0;
    p_sys->stream.tk[i_new].i_start = i_pos;
    p_sys->stream.tk[i_new].i_end   = i_pos;

    /* Read data */
    if( p_sys->stream.i_used < STREAM_READ_ATONCE / 2 )
        p_sys->stream.i_used = STREAM_READ_ATONCE / 2;

    if( AStreamRefillStream( s ) )
        return VLC_EGENERIC;

    return VLC_SUCCESS;
}

static int AStreamRefillStream( stream_t *s )
{
    stream_sys_t *p_sys = s->p_sys;
    stream_track_t *tk = &p_sys->stream.tk[p_sys->stream.i_tk];

    /* We read but won't increase i_start after initial start + offset */
    int i_toread =
        __MIN( p_sys->stream.i_used, STREAM_CACHE_TRACK_SIZE -
               (tk->i_end - tk->i_start - p_sys->stream.i_offset) );
    vlc_bool_t b_read = VLC_FALSE;
    int64_t i_start, i_stop;

    if( i_toread <= 0 ) return VLC_EGENERIC; /* EOF */

    /* msg_Dbg( s, "AStreamRefillStream: toread=%d", i_toread ); */

    i_start = mdate();
    while( i_toread > 0 )
    {
        int i_off = tk->i_end % STREAM_CACHE_TRACK_SIZE;
        int i_read;

        if( s->b_die )
            return VLC_EGENERIC;

        i_read = __MIN( i_toread, STREAM_CACHE_TRACK_SIZE - i_off );
        i_read = AReadStream( s, &tk->p_buffer[i_off], i_read );

        /* msg_Dbg( s, "AStreamRefillStream: read=%d", i_read ); */
        if( i_read <  0 )
        {
            msleep( STREAM_DATA_WAIT );
            continue;
        }
        else if( i_read == 0 )
        {
            if( !b_read ) return VLC_EGENERIC;
            return VLC_SUCCESS;
        }
        b_read = VLC_TRUE;

        /* Update end */
        tk->i_end += i_read;

        /* Windows of STREAM_CACHE_TRACK_SIZE */
        if( tk->i_end - tk->i_start > STREAM_CACHE_TRACK_SIZE )
        {
            int i_invalid = tk->i_end - tk->i_start - STREAM_CACHE_TRACK_SIZE;

            tk->i_start += i_invalid;
            p_sys->stream.i_offset -= i_invalid;
        }

        i_toread -= i_read;
        p_sys->stream.i_used -= i_read;

        p_sys->stat.i_bytes += i_read;
        p_sys->stat.i_read_count++;
    }
    i_stop = mdate();

    p_sys->stat.i_read_time += i_stop - i_start;

    return VLC_SUCCESS;
}

static void AStreamPrebufferStream( stream_t *s )
{
    stream_sys_t *p_sys = s->p_sys;
    access_t     *p_access = p_sys->p_access;

    int64_t i_first = 0;
    int64_t i_start;
    int64_t i_prebuffer = p_sys->b_quick ? STREAM_CACHE_TRACK_SIZE /100 :
        ( (p_access->info.i_title > 1 || p_access->info.i_seekpoint > 1) ?
          STREAM_CACHE_PREBUFFER_SIZE : STREAM_CACHE_TRACK_SIZE / 3 );

    msg_Dbg( s, "pre buffering" );
    i_start = mdate();
    for( ;; )
    {
        stream_track_t *tk = &p_sys->stream.tk[p_sys->stream.i_tk];

        int64_t i_date = mdate();
        int i_read;

        if( s->b_die || tk->i_end >= i_prebuffer ||
            (i_first > 0 && i_first + STREAM_CACHE_PREBUFFER_LENGTH < i_date) )
        {
            int64_t i_byterate;

            /* Update stat */
            p_sys->stat.i_bytes = tk->i_end - tk->i_start;
            p_sys->stat.i_read_time = i_date - i_start;
            i_byterate = ( I64C(1000000) * p_sys->stat.i_bytes ) /
                         (p_sys->stat.i_read_time+1);

            msg_Dbg( s, "prebuffering done "I64Fd" bytes in "I64Fd"s - "
                     I64Fd" kbytes/s",
                     p_sys->stat.i_bytes,
                     p_sys->stat.i_read_time / I64C(1000000),
                     i_byterate / 1024 );
            break;
        }

        /* */
        i_read = STREAM_CACHE_TRACK_SIZE - tk->i_end;
        i_read = __MIN( p_sys->stream.i_read_size, i_read );
        i_read = AReadStream( s, &tk->p_buffer[tk->i_end], i_read );
        if( i_read <  0 )
        {
            msleep( STREAM_DATA_WAIT );
            continue;
        }
        else if( i_read == 0 )
        {
            /* EOF */
            break;
        }

        if( i_first == 0 )
        {
            i_first = mdate();
            msg_Dbg( s, "received first data for our buffer");
        }

        tk->i_end += i_read;

        p_sys->stat.i_read_count++;
    }
}


/****************************************************************************
 * stream_ReadLine:
 ****************************************************************************/
/**
 * Read from the stream untill first newline.
 * \param s Stream handle to read from
 * \return A null-terminated string. This must be freed,
 */
#define STREAM_PROBE_LINE 2048
#define STREAM_LINE_MAX (2048*100)
char *stream_ReadLine( stream_t *s )
{
    char *p_line = NULL;
    int i_line = 0, i_read = 0;

    while( i_read < STREAM_LINE_MAX )
    {
        char *psz_eol;
        uint8_t *p_data;
        int i_data;

        /* Probe new data */
        i_data = stream_Peek( s, &p_data, STREAM_PROBE_LINE );
        if( i_data <= 0 ) break; /* No more data */

        /* Check if there is an EOL */
        if( ( psz_eol = memchr( p_data, '\n', i_data ) ) )
        {
            i_data = (psz_eol - (char *)p_data) + 1;
            p_line = realloc( p_line, i_line + i_data + 1 );
            i_data = stream_Read( s, &p_line[i_line], i_data );
            if( i_data <= 0 ) break; /* Hmmm */
            i_line += (i_data - 1);
            i_read += i_data;

            /* We have our line */
            break;
        }

        /* Read data (+1 for easy \0 append) */
        p_line = realloc( p_line, i_line + STREAM_PROBE_LINE + 1 );
        i_data = stream_Read( s, &p_line[i_line], STREAM_PROBE_LINE );
        if( i_data <= 0 ) break; /* Hmmm */
        i_line += i_data;
        i_read += i_data;
    }

    /* Remove trailing LF/CR */
    while( i_line > 0 && ( p_line[i_line-1] == '\r' ||
           p_line[i_line-1] == '\n') ) i_line--;

    if( i_read > 0 )
    {
        p_line[i_line] = '\0';
        return p_line;
    }

    /* We failed to read any data, probably EOF */
    if( p_line ) free( p_line );
    return NULL;
}

/****************************************************************************
 * Access reading/seeking wrappers to handle concatenated streams.
 ****************************************************************************/
static int AReadStream( stream_t *s, void *p_read, int i_read )
{
    stream_sys_t *p_sys = s->p_sys;
    access_t *p_access = p_sys->p_access;
    int i_read_orig = i_read;

    if( !p_sys->i_list )
    {
        i_read = p_access->pf_read( p_access, p_read, i_read );
        return i_read;
    }

    i_read = p_sys->p_list_access->pf_read( p_sys->p_list_access, p_read,
                                            i_read );

    /* If we reached an EOF then switch to the next stream in the list */
    if( i_read == 0 && p_sys->i_list_index + 1 < p_sys->i_list )
    {
        char *psz_name = p_sys->list[++p_sys->i_list_index]->psz_path;
        access_t *p_list_access;

        msg_Dbg( s, "opening input `%s'", psz_name );

        p_list_access = access2_New( s, p_access->psz_access, 0, psz_name, 0 );

        if( !p_list_access ) return 0;

        if( p_sys->p_list_access != p_access )
            access2_Delete( p_sys->p_list_access );

        p_sys->p_list_access = p_list_access;

        /* We have to read some data */
        return AReadStream( s, p_read, i_read_orig );
    }

    return i_read;
}

static block_t *AReadBlock( stream_t *s, vlc_bool_t *pb_eof )
{
    stream_sys_t *p_sys = s->p_sys;
    access_t *p_access = p_sys->p_access;
    block_t *p_block;
    vlc_bool_t b_eof;

    if( !p_sys->i_list )
    {
        p_block = p_access->pf_block( p_access );
        if( pb_eof ) *pb_eof = p_access->info.b_eof;
        return p_block;
    }

    p_block = p_sys->p_list_access->pf_block( p_access );
    b_eof = p_sys->p_list_access->info.b_eof;
    if( pb_eof ) *pb_eof = b_eof;

    /* If we reached an EOF then switch to the next stream in the list */
    if( !p_block && b_eof && p_sys->i_list_index + 1 < p_sys->i_list )
    {
        char *psz_name = p_sys->list[++p_sys->i_list_index]->psz_path;
        access_t *p_list_access;

        msg_Dbg( s, "opening input `%s'", psz_name );

        p_list_access = access2_New( s, p_access->psz_access, 0, psz_name, 0 );

        if( !p_list_access ) return 0;

        if( p_sys->p_list_access != p_access )
            access2_Delete( p_sys->p_list_access );

        p_sys->p_list_access = p_list_access;

        /* We have to read some data */
        return AReadBlock( s, pb_eof );
    }

    return p_block;
}

static int ASeek( stream_t *s, int64_t i_pos )
{
    stream_sys_t *p_sys = s->p_sys;
    access_t *p_access = p_sys->p_access;

    /* Check which stream we need to access */
    if( p_sys->i_list )
    {
        int i;
        char *psz_name;
        int64_t i_size = 0;
        access_t *p_list_access = 0;

        for( i = 0; i < p_sys->i_list - 1; i++ )
        {
            if( i_pos < p_sys->list[i]->i_size + i_size ) break;
            i_size += p_sys->list[i]->i_size;
        }
        psz_name = p_sys->list[i]->psz_path;

        if( i != p_sys->i_list_index )
            msg_Dbg( s, "opening input `%s'", psz_name );

        if( i != p_sys->i_list_index && i != 0 )
        {
            p_list_access =
                access2_New( s, p_access->psz_access, 0, psz_name, 0 );
        }
        else if( i != p_sys->i_list_index )
        {
            p_list_access = p_access;
        }

        if( p_list_access )
        {
            if( p_sys->p_list_access != p_access )
                access2_Delete( p_sys->p_list_access );

            p_sys->p_list_access = p_list_access;
        }

        p_sys->i_list_index = i;
        return p_sys->p_list_access->pf_seek( p_sys->p_list_access,
                                              i_pos - i_size );
    }

    return p_access->pf_seek( p_access, i_pos );
}