Imported Upstream version 0.79.2
This commit is contained in:
Rogério Brito
committed by
TANIGUCHI Takaki
TANIGUCHI Takaki
parent
c3da7b4a44
commit
bfe15b23fb
300
rs03-recognize.c
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300
rs03-recognize.c
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/* dvdisaster: Additional error correction for optical media.
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* Copyright (C) 2004-2010 Carsten Gnoerlich.
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* Project home page: http://www.dvdisaster.com
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* Email: carsten@dvdisaster.com -or- cgnoerlich@fsfe.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA,
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* or direct your browser at http://www.gnu.org.
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*/
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#include "dvdisaster.h"
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#include "udf.h"
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#include "rs03-includes.h"
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/***
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*** Recognize a RS03 error correction file
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***/
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int RS03RecognizeFile(Method *self, LargeFile *ecc_file)
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{ EccHeader eh;
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int n;
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LargeSeek(ecc_file, 0);
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n = LargeRead(ecc_file, &eh, sizeof(EccHeader));
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if(n != sizeof(EccHeader))
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return FALSE;
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if(strncmp((char*)eh.cookie, "*dvdisaster*", 12))
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return FALSE;
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if(!strncmp((char*)eh.method, "RS03", 4))
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{
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if(self->lastEh) g_free(self->lastEh);
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self->lastEh = g_malloc(sizeof(EccHeader));
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memcpy(self->lastEh, &eh, sizeof(EccHeader));
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#ifdef HAVE_BIG_ENDIAN
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SwapEccHeaderBytes(self->lastEh);
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#endif
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return TRUE;
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}
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return FALSE;
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}
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/***
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*** Recognize RS03 error correction data in the image
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***/
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#if 0
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static int read_fingerprint(LargeFile *file, unsigned char *fingerprint, gint64 sector)
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{ struct MD5Context md5ctxt;
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unsigned char buf[2048];
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int n;
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if(!LargeSeek(file, 2048LL*sector))
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return FALSE;
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n = LargeRead(file, buf, 2048);
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if(n != 2048) return FALSE;
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if(CheckForMissingSector(buf, sector, NULL, 0) != SECTOR_PRESENT)
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return FALSE;
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MD5Init(&md5ctxt);
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MD5Update(&md5ctxt, buf, 2048);
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MD5Final(fingerprint, &md5ctxt);
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return TRUE;
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}
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#endif
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EccHeader* ValidHeader(unsigned char *buf, gint64 hdr_pos)
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{ EccHeader *eh = (EccHeader*)buf;
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guint32 recorded_crc, real_crc;
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// unsigned char fingerprint[16];
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/* Medium read error in ecc header? */
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if( (CheckForMissingSector(buf, hdr_pos, NULL, 0) != SECTOR_PRESENT)
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|| (CheckForMissingSector(buf+2048, hdr_pos+1, NULL, 0) != SECTOR_PRESENT))
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return NULL;
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/* See if the magic cookie is there */
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if( strncmp((char*)eh->cookie, "*dvdisaster*", 12)
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|| strncmp((char*)eh->method, "RS03", 4)) // FIXME
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return NULL;
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/* Examine the checksum */
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recorded_crc = eh->selfCRC;
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#ifdef HAVE_BIG_ENDIAN
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eh->selfCRC = 0x47504c00;
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#else
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eh->selfCRC = 0x4c5047;
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#endif
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real_crc = Crc32((unsigned char*)eh, 4096);
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if(real_crc != recorded_crc)
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return NULL;
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/* Check the fingerprint */
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eh = g_malloc(sizeof(EccHeader));
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memcpy(eh, buf, sizeof(EccHeader));
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#ifdef HAVE_BIG_ENDIAN
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SwapEccHeaderBytes(eh);
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#endif
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eh->selfCRC = recorded_crc;
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#if 0
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status = read_fingerprint(file, fingerprint, eh->fpSector);
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if(!status) /* be optimistic if fingerprint sector is unreadable */
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return eh;
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if(!memcmp(fingerprint, eh->mediumFP, 16)) /* good fingerprint */
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{ printf("RS03 header found\n");
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return eh;
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}
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g_free(eh);
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#endif
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return eh;
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}
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EccHeader* FindRS03HeaderInImage(LargeFile *file)
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{ EccHeader *eh = NULL;
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IsoInfo *ii;
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gint64 hdr_pos;
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unsigned char buf[4096];
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Verbose("FindRS03HeaderInImage(%s)\n", file->path);
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/*** Try to find the header behind the ISO image */
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ii = ExamineUDF(NULL, file);
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if(!ii) Verbose(" . NO ISO structures found!\n");
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if(ii)
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{ hdr_pos = ii->volumeSize;
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if(LargeSeek(file, 2048*hdr_pos))
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{ int n = LargeRead(file, buf, sizeof(EccHeader));
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if(n == sizeof(EccHeader))
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{ eh = ValidHeader(buf, hdr_pos);
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if(eh)
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{ Verbose("FindRS03HeaderInImage(): Header found at pos +0\n");
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return eh;
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}
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}
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}
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hdr_pos = ii->volumeSize - 150;
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if(LargeSeek(file, 2048*hdr_pos))
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{ int n = LargeRead(file, buf, sizeof(EccHeader));
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if(n == sizeof(EccHeader))
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{ eh = ValidHeader(buf, hdr_pos);
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if(eh)
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{ Verbose("FindRS03HeaderInImage(): Header found at pos -150\n");
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return eh;
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}
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}
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}
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}
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return NULL;
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}
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typedef struct
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{ gint64 bidx[256];
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char *layer[256];
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} recognize_context;
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static void free_recognize_context(recognize_context *rc)
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{ int i;
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for(i=0; i<255; i++)
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if(rc->layer[i])
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g_free(rc->layer[i]);
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g_free(rc);
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}
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int RS03RecognizeImage(Method *self, LargeFile *ecc_file)
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{ recognize_context *rc = g_malloc0(sizeof(recognize_context));
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EccHeader *eh;
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gint64 file_size;
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gint64 layer_size;
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int ecc_block,ndata,nroots;
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int i;
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/* Easy shot: Locate the ecc header in the image */
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eh = FindRS03HeaderInImage(ecc_file);
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if(eh)
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{ if(self->lastEh) g_free(self->lastEh);
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self->lastEh = eh;
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return TRUE;
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}
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/* No exhaustive search unless explicitly okayed by user */
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if(!Closure->examineRS03)
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return FALSE;
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/* Ugly case. Experimentally try the RS-Code. */
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Verbose("RS03RecognizeImage(): No EH\n");
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if(!LargeStat(Closure->imageName, &file_size))
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return FALSE;
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file_size /= 2048;
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if(Closure->debugMode && Closure->mediumSize)
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layer_size = Closure->mediumSize/GF_FIELDMAX;
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else
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{ if(file_size < CDR_SIZE) layer_size = CDR_SIZE/GF_FIELDMAX;
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else if(file_size < DVD_SL_SIZE) layer_size = DVD_SL_SIZE/GF_FIELDMAX;
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else if(file_size < DVD_DL_SIZE) layer_size = DVD_DL_SIZE/GF_FIELDMAX;
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else if(file_size < BD_SL_SIZE) layer_size = BD_SL_SIZE/GF_FIELDMAX;
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else layer_size = BD_DL_SIZE/GF_FIELDMAX;
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}
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Verbose(".. trying layer size %lld\n", layer_size);
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for(i=0; i<255; i++)
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{ rc->bidx[i] = i*layer_size;
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rc->layer[i] = malloc(2048);
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}
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/* Now try all ecc blocks */
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for(ecc_block=0; ecc_block<layer_size; ecc_block++)
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{ Verbose("Assembling ecc block %d\n", ecc_block);
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/* Assemble the ecc block */
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for(i=0; i<255; i++)
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{ gint64 sector = rc->bidx[i]++;
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int n;
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if(!LargeSeek(ecc_file, (gint64)(2048*sector)))
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Stop(_("Failed seeking to sector %lld in image: %s"),
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sector, strerror(errno));
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n = LargeRead(ecc_file, rc->layer[i], 2048);
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if(n != 2048)
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Stop(_("Failed reading sector %lld in image: %s"),sector,strerror(errno));
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}
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/* Experimentally apply the RS code */
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for(ndata=255-8; ndata >=85; ndata--)
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{ CrcBlock *cb = (CrcBlock*)rc->layer[ndata];
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/* Do the real decode here */
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/* See if we have decoded a CRC block */
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if( !memcmp(cb->cookie, "*dvdisaster*", 12)
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||!memcmp(cb->method, "RS03", 4))
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{
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nroots = 255-ndata-1;
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Verbose(".. Success: rediscovered format with %d roots\n", nroots);
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if(self->lastEh) g_free(self->lastEh);
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self->lastEh = g_malloc(sizeof(EccHeader));
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ReconstructRS03Header(self->lastEh, cb);
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//FIXME: endianess okay?
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free_recognize_context(rc);
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return TRUE;
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}
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}
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}
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free_recognize_context(rc);
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return FALSE;
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}
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