stream.c

VLC Player Source Code

/*****************************************************************************
 * stream.c
 *****************************************************************************
 * Copyright (C) 1999-2004 the VideoLAN team
 * $Id: 1e442b407cc2630e7012b49cf672806a52054be9 $
 *
 * Authors: Laurent Aimar <[e-mail]>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>

#include <assert.h>

#include "input_internal.h"

#undef STREAM_DEBUG

/* TODO:
 *  - tune the 2 methods (block/stream)
 *  - compute cost for seek
 *  - improve stream mode seeking with closest segments
 *  - ...
 *  - Maybe remove (block/stream) in favour of immediate
 */

/* Two methods:
 *  - using pf_block
 *      One linked list of data read
 *  - using pf_read
 *      More complex scheme using mutliple track to avoid seeking
 *  - using directly the access (only indirection for peeking).
 *      This method is known to introduce much less latency.
 *      It should probably defaulted (instead of the stream method (2)).
 */

/* How many tracks we have, currently only used for stream mode */
#ifdef OPTIMIZE_MEMORY
#   define STREAM_CACHE_TRACK 1
    /* Max size of our cache 128Ko per track */
#   define STREAM_CACHE_SIZE  (STREAM_CACHE_TRACK*1024*128)
#else
#   define STREAM_CACHE_TRACK 3
    /* Max size of our cache 4Mo per track */
#   define STREAM_CACHE_SIZE  (4*STREAM_CACHE_TRACK*1024*1024)
#endif

/* How many data we try to prebuffer */
#define STREAM_CACHE_PREBUFFER_SIZE (32767)
/* Maximum time we take to pre-buffer */
#define STREAM_CACHE_PREBUFFER_LENGTH (100*1000)

/* Method1: Simple, for pf_block.
 *  We get blocks and put them in the linked list.
 *  We release blocks once the total size is bigger than CACHE_BLOCK_SIZE
 */
#define STREAM_DATA_WAIT 40000       /* Time between before a pf_block retry */

/* Method2: A bit more complex, for pf_read
 *  - We use ring buffers, only one if unseekable, all if seekable
 *  - Upon seek date current ring, then search if one ring match the pos,
 *      yes: switch to it, seek the access to match the end of the ring
 *      no: search the ring with i_end the closer to i_pos,
 *          if close enough, read data and use this ring
 *          else use the oldest ring, seek and use it.
 *
 *  TODO: - with access non seekable: use all space available for only one ring, but
 *          we have to support seekable/non-seekable switch on the fly.
 *        - compute a good value for i_read_size
 *        - ?
 */
#define STREAM_READ_ATONCE 32767
#define STREAM_CACHE_TRACK_SIZE (STREAM_CACHE_SIZE/STREAM_CACHE_TRACK)

typedef struct
{
    int64_t i_date;

    int64_t i_start;
    int64_t i_end;

    uint8_t *p_buffer;

} stream_track_t;

typedef struct
{
    char     *psz_path;
    int64_t  i_size;

} access_entry_t;

typedef enum stream_read_method_t
{
    Immediate,
    Block,
    Stream
} stream_read_method_t;

struct stream_sys_t
{
    access_t    *p_access;

    stream_read_method_t   method;    /* method to use */

    int64_t     i_pos;      /* Current reading offset */

    /* Method 1: pf_block */
    struct
    {
        int64_t i_start;        /* Offset of block for p_first */
        int64_t i_offset;       /* Offset for data in p_current */
        block_t *p_current;     /* Current block */

        int     i_size;         /* Total amount of data in the list */
        block_t *p_first;
        block_t **pp_last;

    } block;

    /* Method 2: for pf_read */
    struct
    {
        int i_offset;   /* Buffer offset in the current track */
        int i_tk;       /* Current track */
        stream_track_t tk[STREAM_CACHE_TRACK];

        /* Global buffer */
        uint8_t *p_buffer;

        /* */
        int i_used; /* Used since last read */
        int i_read_size;

    } stream;

    /* Method 3: for pf_read */
    struct
    {
        int64_t i_end;
        uint8_t *p_buffer;
    } immediate;

    /* Peek temporary buffer */
    unsigned int i_peek;
    uint8_t *p_peek;

    /* Stat for both method */
    struct
    {
        bool b_fastseek;  /* From access */

        /* Stat about reading data */
        int64_t i_read_count;
        int64_t i_bytes;
        int64_t i_read_time;

        /* Stat about seek */
        int     i_seek_count;
        int64_t i_seek_time;

    } stat;

    /* Streams list */
    int            i_list;
    access_entry_t **list;
    int            i_list_index;
    access_t       *p_list_access;

    /* Preparse mode ? */
    bool      b_quick;
};

/* Method 1: */
static int  AStreamReadBlock( stream_t *s, void *p_read, unsigned int i_read );
static int  AStreamPeekBlock( stream_t *s, const uint8_t **p_peek, unsigned int i_read );
static int  AStreamSeekBlock( stream_t *s, int64_t i_pos );
static void AStreamPrebufferBlock( stream_t *s );
static block_t *AReadBlock( stream_t *s, bool *pb_eof );

/* Method 2 */
static int  AStreamReadStream( stream_t *s, void *p_read, unsigned int i_read );
static int  AStreamPeekStream( stream_t *s, const uint8_t **pp_peek, unsigned int i_read );
static int  AStreamSeekStream( stream_t *s, int64_t i_pos );
static void AStreamPrebufferStream( stream_t *s );
static int  AReadStream( stream_t *s, void *p_read, unsigned int i_read );

/* Method 3 */
static int  AStreamReadImmediate( stream_t *s, void *p_read, unsigned int i_read );
static int  AStreamPeekImmediate( stream_t *s, const uint8_t **pp_peek, unsigned int i_read );
static int  AStreamSeekImmediate( stream_t *s, int64_t i_pos );

/* Common */
static int AStreamControl( stream_t *s, int i_query, va_list );
static void AStreamDestroy( stream_t *s );
static void UStreamDestroy( stream_t *s );
static int  ASeek( stream_t *s, int64_t i_pos );

/****************************************************************************
 * Method 3 helpers:
 ****************************************************************************/

static inline int64_t stream_buffered_size( stream_t *s )
{
    return s->p_sys->immediate.i_end;
}

static inline void stream_buffer_empty( stream_t *s, int length )
{
    length = __MAX( stream_buffered_size( s ), length );
    if( length )
    {
        memmove( s->p_sys->immediate.p_buffer,
                 s->p_sys->immediate.p_buffer + length,
                 stream_buffered_size( s ) - length );
    }
    s->p_sys->immediate.i_end -= length;
}

static inline void stream_buffer_fill( stream_t *s, int length )
{
    s->p_sys->immediate.i_end += length;
}

static inline uint8_t * stream_buffer( stream_t *s )
{
    return s->p_sys->immediate.p_buffer;
}

/****************************************************************************
 * stream_UrlNew: create a stream from a access
 ****************************************************************************/
stream_t *__stream_UrlNew( vlc_object_t *p_parent, const char *psz_url )
{
    const char *psz_access, *psz_demux;
    char *psz_path;
    access_t *p_access;
    stream_t *p_res;

    if( !psz_url )
        return NULL;

    char psz_dup[strlen( psz_url ) + 1];
    strcpy( psz_dup, psz_url );
    input_SplitMRL( &psz_access, &psz_demux, &psz_path, psz_dup );

    /* Now try a real access */
    p_access = access_New( p_parent, psz_access, psz_demux, psz_path );

    if( p_access == NULL )
    {
        msg_Err( p_parent, "no suitable access module for `%s'", psz_url );
        return NULL;
    }

    if( !( p_res = stream_AccessNew( p_access, true ) ) )
    {
        access_Delete( p_access );
        return NULL;
    }

    p_res->pf_destroy = UStreamDestroy;
    return p_res;
}

stream_t *stream_AccessNew( access_t *p_access, bool b_quick )
{
    stream_t *s = vlc_stream_create( VLC_OBJECT(p_access) );
    stream_sys_t *p_sys;
    char *psz_list = NULL;

    if( !s ) return NULL;

    /* Attach it now, needed for b_die */
    vlc_object_attach( s, p_access );

    s->pf_read   = NULL;    /* Set up later */
    s->pf_peek   = NULL;
    s->pf_control = AStreamControl;
    s->pf_destroy = AStreamDestroy;

    s->p_sys = p_sys = malloc( sizeof( stream_sys_t ) );
    if( p_sys == NULL )
        goto error;

    /* UTF16 and UTF32 text file conversion */
    s->i_char_width = 1;
    s->b_little_endian = false;
    s->conv = (vlc_iconv_t)(-1);

    /* Common field */
    p_sys->p_access = p_access;
    if( p_access->pf_block )
        p_sys->method = Block;
    else if (var_CreateGetBool( s, "use-stream-immediate"))
        p_sys->method = Immediate;
    else
        p_sys->method = Stream;

    p_sys->i_pos = p_access->info.i_pos;

    /* Stats */
    access_Control( p_access, ACCESS_CAN_FASTSEEK, &p_sys->stat.b_fastseek );
    p_sys->stat.i_bytes = 0;
    p_sys->stat.i_read_time = 0;
    p_sys->stat.i_read_count = 0;
    p_sys->stat.i_seek_count = 0;
    p_sys->stat.i_seek_time = 0;

    p_sys->i_list = 0;
    p_sys->list = 0;
    p_sys->i_list_index = 0;
    p_sys->p_list_access = 0;

    p_sys->b_quick = b_quick;

    /* Get the additional list of inputs if any (for concatenation) */
    if( (psz_list = var_CreateGetString( s, "input-list" )) && *psz_list )
    {
        access_entry_t *p_entry = malloc( sizeof(access_entry_t) );
        if( p_entry == NULL )
            goto error;
        char *psz_name, *psz_parser = psz_name = psz_list;

        p_sys->p_list_access = p_access;
        p_entry->i_size = p_access->info.i_size;
        p_entry->psz_path = strdup( p_access->psz_path );
        if( p_entry->psz_path == NULL )
        {
            free( p_entry );
            goto error;
        }
        TAB_APPEND( p_sys->i_list, p_sys->list, p_entry );
        msg_Dbg( p_access, "adding file `%s', (%"PRId64" bytes)",
                 p_entry->psz_path, p_access->info.i_size );

        while( psz_name && *psz_name )
        {
            psz_parser = strchr( psz_name, ',' );
            if( psz_parser ) *psz_parser = 0;

            psz_name = strdup( psz_name );
            if( psz_name )
            {
                access_t *p_tmp = access_New( p_access, p_access->psz_access,
                                               "", psz_name );

                if( !p_tmp )
                {
                    psz_name = psz_parser;
                    if( psz_name ) psz_name++;
                    continue;
                }

                msg_Dbg( p_access, "adding file `%s', (%"PRId64" bytes)",
                         psz_name, p_tmp->info.i_size );

                p_entry = malloc( sizeof(access_entry_t) );
                if( p_entry == NULL )
                    goto error;
                p_entry->i_size = p_tmp->info.i_size;
                p_entry->psz_path = psz_name;
                TAB_APPEND( p_sys->i_list, p_sys->list, p_entry );

                access_Delete( p_tmp );
            }

            psz_name = psz_parser;
            if( psz_name ) psz_name++;
        }
    }
    FREENULL( psz_list );

    /* Peek */
    p_sys->i_peek = 0;
    p_sys->p_peek = NULL;

    if( p_sys->method == Block )
    {
        msg_Dbg( s, "Using AStream*Block" );
        s->pf_read = AStreamReadBlock;
        s->pf_peek = AStreamPeekBlock;

        /* Init all fields of p_sys->block */
        p_sys->block.i_start = p_sys->i_pos;
        p_sys->block.i_offset = 0;
        p_sys->block.p_current = NULL;
        p_sys->block.i_size = 0;
        p_sys->block.p_first = NULL;
        p_sys->block.pp_last = &p_sys->block.p_first;

        /* Do the prebuffering */
        AStreamPrebufferBlock( s );

        if( p_sys->block.i_size <= 0 )
        {
            msg_Err( s, "cannot pre fill buffer" );
            goto error;
        }
    }
    else if (p_sys->method == Immediate)
    {
        msg_Dbg( s, "Using AStream*Immediate" );

        s->pf_read = AStreamReadImmediate;
        s->pf_peek = AStreamPeekImmediate;

        /* Allocate/Setup our tracks (useful to peek)*/
        p_sys->immediate.i_end = 0;
        p_sys->immediate.p_buffer = malloc( STREAM_CACHE_SIZE );