dvd_udf.c

有关mpeg2的deocde代码

/*
 * This code is based on dvdudf by:
 *   Christian Wolff <[e-mail]>.
 *
 * Modifications by:
 *   Billy Biggs <[e-mail]>.
 *   Bj鰎n Englund <[e-mail]>.
 *
 * dvdudf: parse and read the UDF volume information of a DVD Video
 * Copyright (C) 1999 Christian Wolff for convergence integrated media
 * GmbH The author can be reached at [e-mail], the
 * project's page is at http://linuxtv.org/dvd/
 * 
 * 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.  Or, point your browser to
 * http://www.gnu.org/copyleft/gpl.html
 */
 
#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <inttypes.h>

#include "dvd_reader.h"
#include "dvd_udf.h"

/* Private but located in/shared with dvd_reader.c */
extern int UDFReadBlocksRaw( dvd_reader_t *device, uint32_t lb_number,
				size_t block_count, unsigned char *data, 
				int encrypted );

/* It's required to either fail or deliver all the blocks asked for. */
static int DVDReadLBUDF( dvd_reader_t *device, uint32_t lb_number,
			 size_t block_count, unsigned char *data, 
			 int encrypted )
{
  int ret;
  size_t count = block_count;
  
  while(count > 0) {
    
    ret = UDFReadBlocksRaw(device, lb_number, count, data, encrypted);
        
    if(ret <= 0) {
      /* One of the reads failed or nothing more to read, too bad.
       * We won't even bother returning the reads that went ok. */
      return ret;
    }
    
    count -= (size_t)ret;
    lb_number += (uint32_t)ret;
  }

  return block_count;
}


#ifndef NULL
#define NULL ((void *)0)
#endif

struct Partition {
    int valid;
    char VolumeDesc[128];
    uint16_t Flags;
    uint16_t Number;
    char Contents[32];
    uint32_t AccessType;
    uint32_t Start;
    uint32_t Length;
};

struct AD {
    uint32_t Location;
    uint32_t Length;
    uint8_t  Flags;
    uint16_t Partition;
};

struct extent_ad {
  uint32_t location;
  uint32_t length;
};

struct avdp_t {
  struct extent_ad mvds;
  struct extent_ad rvds;
};

struct pvd_t {
  uint8_t VolumeIdentifier[32];
  uint8_t VolumeSetIdentifier[128];
};

struct lbudf {
  uint32_t lb;
  uint8_t *data;
};

struct icbmap {
  uint32_t lbn;
  struct AD file;
  uint8_t filetype;
};

struct udf_cache {
  int avdp_valid;
  struct avdp_t avdp;
  int pvd_valid;
  struct pvd_t pvd;
  int partition_valid;
  struct Partition partition;
  int rooticb_valid;
  struct AD rooticb;
  int lb_num;
  struct lbudf *lbs;
  int map_num;
  struct icbmap *maps;
};

typedef enum {
  PartitionCache, RootICBCache, LBUDFCache, MapCache, AVDPCache, PVDCache
} UDFCacheType;

extern void *GetUDFCacheHandle(dvd_reader_t *device);
extern void SetUDFCacheHandle(dvd_reader_t *device, void *cache);

void FreeUDFCache(void *cache)
{
  struct udf_cache *c = (struct udf_cache *)cache;
  if(c == NULL) {
    return;
  }
  if(c->lbs) {
    free(c->lbs);
  }
  if(c->maps) {
    free(c->maps);
  }
  free(c);
}


static int GetUDFCache(dvd_reader_t *device, UDFCacheType type,
		       uint32_t nr, void *data)
{
  int n;
  struct udf_cache *c;

  if(DVDUDFCacheLevel(device, -1) <= 0) {
    return 0;
  }
  
  c = (struct udf_cache *)GetUDFCacheHandle(device);
  
  if(c == NULL) {
    return 0;
  }
  
  switch(type) {
  case AVDPCache:
    if(c->avdp_valid) {
      *(struct avdp_t *)data = c->avdp;
      return 1;
    }    
    break;
  case PVDCache:
    if(c->pvd_valid) {
      *(struct pvd_t *)data = c->pvd;
      return 1;
    }    
    break;
  case PartitionCache:
    if(c->partition_valid) {
      *(struct Partition *)data = c->partition;
      return 1;
    }
    break;
  case RootICBCache:
    if(c->rooticb_valid) {
      *(struct AD *)data = c->rooticb;
      return 1;
    }
    break;
  case LBUDFCache:
    for(n = 0; n < c->lb_num; n++) {
      if(c->lbs[n].lb == nr) {
      *(uint8_t **)data = c->lbs[n].data;
      return 1;
      }
    }
    break;
  case MapCache:
    for(n = 0; n < c->map_num; n++) {
      if(c->maps[n].lbn == nr) {
       *(struct icbmap *)data = c->maps[n];
       return 1;
      }
    }
    break;
  default:
    break;
  }
  
  return 0;
}

static int SetUDFCache(dvd_reader_t *device, UDFCacheType type,
		       uint32_t nr, void *data)
{
  int n;
  struct udf_cache *c;

  if(DVDUDFCacheLevel(device, -1) <= 0) {
    return 0;
  }

  c = (struct udf_cache *)GetUDFCacheHandle(device);
  
  if(c == NULL) {
    c = calloc(1, sizeof(struct udf_cache));    
    //    fprintf(stderr, "calloc: %d\n", sizeof(struct udf_cache));    
    if(c == NULL) {
      return 0;
    }
    SetUDFCacheHandle(device, c);
  }
  
  
  switch(type) {
  case AVDPCache:
    c->avdp = *(struct avdp_t *)data; 
    c->avdp_valid = 1;
    break;
  case PVDCache:
    c->pvd = *(struct pvd_t *)data; 
    c->pvd_valid = 1;
    break;
  case PartitionCache:
    c->partition = *(struct Partition *)data; 
    c->partition_valid = 1;
    break;
  case RootICBCache:
    c->rooticb = *(struct AD *)data; 
    c->rooticb_valid = 1;
    break;
  case LBUDFCache:
    for(n = 0; n < c->lb_num; n++) {
      if(c->lbs[n].lb == nr) {
       /* replace with new data */
       c->lbs[n].data = *(uint8_t **)data;
       c->lbs[n].lb = nr;
       return 1;
      }
    }
    c->lb_num++;
    c->lbs = realloc(c->lbs, c->lb_num * sizeof(struct lbudf));
    /*
    fprintf(stderr, "realloc lb: %d * %d = %d\n",
	    c->lb_num, sizeof(struct lbudf),
	    c->lb_num * sizeof(struct lbudf));
    */
    if(c->lbs == NULL) {
      c->lb_num = 0;
      return 0;
    }
    c->lbs[n].data = *(uint8_t **)data;
    c->lbs[n].lb = nr;
    break;
  case MapCache:
    for(n = 0; n < c->map_num; n++) {
      if(c->maps[n].lbn == nr) {
       /* replace with new data */
       c->maps[n] = *(struct icbmap *)data;
       c->maps[n].lbn = nr;
       return 1;
      }
    }
    c->map_num++;
    c->maps = realloc(c->maps, c->map_num * sizeof(struct icbmap));
    /*
    fprintf(stderr, "realloc maps: %d * %d = %d\n",
	    c->map_num, sizeof(struct icbmap),
	    c->map_num * sizeof(struct icbmap));
    */
    if(c->maps == NULL) {
      c->map_num = 0;
      return 0;
    }
    c->maps[n] = *(struct icbmap *)data;
    c->maps[n].lbn = nr;
    break;
  default:
    return 0;
  }
    
  return 1;
}


/* For direct data access, LSB first */
#define GETN1(p) ((uint8_t)data[p])
#define GETN2(p) ((uint16_t)data[p] | ((uint16_t)data[(p) + 1] << 8))
#define GETN3(p) ((uint32_t)data[p] | ((uint32_t)data[(p) + 1] << 8) \
		  | ((uint32_t)data[(p) + 2] << 16))
#define GETN4(p) ((uint32_t)data[p] \
		  | ((uint32_t)data[(p) + 1] << 8) \
		  | ((uint32_t)data[(p) + 2] << 16) \
		  | ((uint32_t)data[(p) + 3] << 24))
/* This is wrong with regard to endianess */
#define GETN(p, n, target) memcpy(target, &data[p], n)

static int Unicodedecode( uint8_t *data, int len, char *target ) 
{
    int p = 1, i = 0;

    if( ( data[ 0 ] == 8 ) || ( data[ 0 ] == 16 ) ) do {
        if( data[ 0 ] == 16 ) p++;  /* Ignore MSB of unicode16 */
        if( p < len ) {
            target[ i++ ] = data[ p++ ];
        }
    } while( p < len );

    target[ i ] = '\0';
    return 0;
}

static int UDFDescriptor( uint8_t *data, uint16_t *TagID ) 
{
    *TagID = GETN2(0);
    // TODO: check CRC 'n stuff
    return 0;
}

static int UDFExtentAD( uint8_t *data, uint32_t *Length, uint32_t *Location ) 
{
    *Length   = GETN4(0);
    *Location = GETN4(4);
    return 0;
}

static int UDFShortAD( uint8_t *data, struct AD *ad, 
		       struct Partition *partition ) 
{
    ad->Length = GETN4(0);
    ad->Flags = ad->Length >> 30;
    ad->Length &= 0x3FFFFFFF;
    ad->Location = GETN4(4);
    ad->Partition = partition->Number; // use number of current partition
    return 0;
}

static int UDFLongAD( uint8_t *data, struct AD *ad )
{
    ad->Length = GETN4(0);
    ad->Flags = ad->Length >> 30;
    ad->Length &= 0x3FFFFFFF;
    ad->Location = GETN4(4);
    ad->Partition = GETN2(8);
    //GETN(10, 6, Use);
    return 0;
}

static int UDFExtAD( uint8_t *data, struct AD *ad )
{
    ad->Length = GETN4(0);
    ad->Flags = ad->Length >> 30;
    ad->Length &= 0x3FFFFFFF;
    ad->Location = GETN4(12);
    ad->Partition = GETN2(16);
    //GETN(10, 6, Use);
    return 0;
}

static int UDFICB( uint8_t *data, uint8_t *FileType, uint16_t *Flags )
{
    *FileType = GETN1(11);
    *Flags = GETN2(18);
    return 0;
}


static int UDFPartition( uint8_t *data, uint16_t *Flags, uint16_t *Number,
			 char *Contents, uint32_t *Start, uint32_t *Length )
{
    *Flags = GETN2(20);
    *Number = GETN2(22);
    GETN(24, 32, Contents);
    *Start = GETN4(188);
    *Length = GETN4(192);
    return 0;
}

/**
 * Reads the volume descriptor and checks the parameters.  Returns 0 on OK, 1
 * on error.
 */
static int UDFLogVolume( uint8_t *data, char *VolumeDescriptor )
{
    uint32_t lbsize, MT_L, N_PM;
    Unicodedecode(&data[84], 128, VolumeDescriptor);
    lbsize = GETN4(212);  // should be 2048
    MT_L = GETN4(264);    // should be 6
    N_PM = GETN4(268);    // should be 1
    if (lbsize != DVD_VIDEO_LB_LEN) return 1;
    return 0;
}

static int UDFFileEntry( uint8_t *data, uint8_t *FileType, 
			 struct Partition *partition, struct AD *ad )
{
    uint16_t flags;
    uint32_t L_EA, L_AD;
    unsigned int p;

    UDFICB( &data[ 16 ], FileType, &flags );
   
    /* Init ad for an empty file (i.e. there isn't a AD, L_AD == 0 ) */
    ad->Length = GETN4( 60 ); // Really 8 bytes a 56
    ad->Flags = 0;
    ad->Location = 0; // what should we put here? 
    ad->Partition = partition->Number; // use number of current partition

    L_EA = GETN4( 168 );
    L_AD = GETN4( 172 );
    p = 176 + L_EA;
    while( p < 176 + L_EA + L_AD ) {
        switch( flags & 0x0007 ) {
            case 0: UDFShortAD( &data[ p ], ad, partition ); p += 8;  break;
            case 1: UDFLongAD( &data[ p ], ad );  p += 16; break;
            case 2: UDFExtAD( &data[ p ], ad );   p += 20; break;
            case 3:
                switch( L_AD ) {
                    case 8:  UDFShortAD( &data[ p ], ad, partition ); break;
                    case 16: UDFLongAD( &data[ p ], ad );  break;
                    case 20: UDFExtAD( &data[ p ], ad );   break;
                }
                p += L_AD;
                break;
            default:
                p += L_AD; break;
        }
    }
    return 0;
}

static int UDFFileIdentifier( uint8_t *data, uint8_t *FileCharacteristics,
			      char *FileName, struct AD *FileICB )
{
    uint8_t L_FI;
    uint16_t L_IU;

    *FileCharacteristics = GETN1(18);
    L_FI = GETN1(19);
    UDFLongAD(&data[20], FileICB);
    L_IU = GETN2(36);
    if (L_FI) Unicodedecode(&data[38 + L_IU], L_FI, FileName);
    else FileName[0] = '\0';
    return 4 * ((38 + L_FI + L_IU + 3) / 4);
}

/**
 * Maps ICB to FileAD
 * ICB: Location of ICB of directory to scan
 * FileType: Type of the file
 * File: Location of file the ICB is pointing to
 * return 1 on success, 0 on error;
 */
static int UDFMapICB( dvd_reader_t *device, struct AD ICB, uint8_t *FileType,
		      struct Partition *partition, struct AD *File ) 
{
    uint8_t LogBlock[DVD_VIDEO_LB_LEN];
    uint32_t lbnum;
    uint16_t TagID;
    struct icbmap tmpmap;

    lbnum = partition->Start + ICB.Location;
    tmpmap.lbn = lbnum;
    if(GetUDFCache(device, MapCache, lbnum, &tmpmap)) {
      *FileType = tmpmap.filetype;
      *File = tmpmap.file;