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/*
File: file_flac.c
Copyright (C) 2007 Christophe GRENIER <grenier@cgsecurity.org>
This software 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 the Free Software Foundation, Inc., 51
Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_flac)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "filegen.h"
#include "common.h"
#include "log.h"
/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_flac(file_stat_t *file_stat);
const file_hint_t file_hint_flac= {
.extension="flac",
.description="FLAC audio",
.max_filesize=(uint64_t)1500*1024*1024,
.recover=1,
.enable_by_default=1,
.register_header_check=®ister_header_check_flac
};
/* https://xiph.org/flac/format.html */
/*@
@ requires file_recovery->data_check==&data_check_flac_metadata;
@ requires valid_data_check_param(buffer, buffer_size, file_recovery);
@ terminates \true;
@ ensures valid_data_check_result(\result, file_recovery);
@ assigns file_recovery->calculated_file_size, file_recovery->data_check;
@*/
static data_check_t data_check_flac_metadata(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
{
/*@ assert file_recovery->calculated_file_size <= PHOTOREC_MAX_FILE_SIZE; */
/*@ assert file_recovery->file_size <= PHOTOREC_MAX_FILE_SIZE; */
/*@
@ loop assigns file_recovery->calculated_file_size, file_recovery->data_check;
@ loop variant file_recovery->file_size + buffer_size/2 - (file_recovery->calculated_file_size + 4);
@*/
while(file_recovery->calculated_file_size + buffer_size/2 >= file_recovery->file_size &&
file_recovery->calculated_file_size + 4 < file_recovery->file_size + buffer_size/2)
{
const unsigned int i=file_recovery->calculated_file_size + buffer_size/2 - file_recovery->file_size;
/*@ assert 0 <= i < buffer_size - 4; */
const uint32_t *p32=(const uint32_t *)&buffer[i];
const uint32_t size=be32(*p32)&0x00ffffff;
#ifdef DEBUG_FLAC
log_info("data_check_flac_metadata calculated_file_size=0x%llx: 0x%02x\n",
(long long unsigned)file_recovery->calculated_file_size, buffer[i]);
#endif
if((buffer[i]&0x7f)==0x7f)
return DC_ERROR;
file_recovery->calculated_file_size+=(uint64_t)4+size;
if((buffer[i]&0x80)==0x80)
{
file_recovery->data_check=NULL;
return DC_CONTINUE;
}
}
return DC_CONTINUE;
}
/*@
@ requires buffer_size >= 8;
@ requires separation: \separated(&file_hint_flac, buffer+(..), file_recovery, file_recovery_new);
@ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
@ terminates \true;
@ ensures valid_header_check_result(\result, file_recovery_new);
@ assigns *file_recovery_new;
@*/
static int header_check_flac(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
const uint32_t *p32=(const uint32_t *)&buffer[4];
const uint32_t size=be32(*p32)&0x00ffffff;
reset_file_recovery(file_recovery_new);
#ifdef DJGPP
file_recovery_new->extension="flc";
#else
file_recovery_new->extension=file_hint_flac.extension;
#endif
file_recovery_new->min_filesize=4+size;
if(file_recovery_new->blocksize >= 4)
{
file_recovery_new->calculated_file_size=4;
file_recovery_new->data_check=&data_check_flac_metadata;
}
return 1;
}
static void register_header_check_flac(file_stat_t *file_stat)
{
/* Stream marker followed by STREAMINFO Metadata block */
static const unsigned char flac_header[5]= {'f', 'L', 'a', 'C', 0x00};
static const unsigned char flac_header2[5]= {'f', 'L', 'a', 'C', 0x80};
register_header_check(0, flac_header,sizeof(flac_header), &header_check_flac, file_stat);
#ifndef DISABLED_FOR_FRAMAC
register_header_check(0, flac_header2,sizeof(flac_header2), &header_check_flac, file_stat);
#endif
}
#endif
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