2007-10-29 22:38:52 +01:00
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/*
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File: file_gif.c
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Copyright (C) 1998-2007 Christophe GRENIER <grenier@cgsecurity.org>
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This software 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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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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You should have received a copy of the GNU General Public License along
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with this program; if not, write the Free Software Foundation, Inc., 51
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Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#include <stdio.h>
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#include "types.h"
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#include "filegen.h"
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2014-03-11 21:44:31 +01:00
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#include "log.h"
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2007-10-29 22:38:52 +01:00
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static void register_header_check_gif(file_stat_t *file_stat);
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static int header_check_gif(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);
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static void file_check_gif(file_recovery_t *file_recovery);
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2013-12-14 21:36:24 +01:00
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static data_check_t data_check_gif(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery);
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static data_check_t data_check_gif2(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery);
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2007-10-29 22:38:52 +01:00
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const file_hint_t file_hint_gif= {
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.extension="gif",
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.description="Graphic Interchange Format",
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.max_filesize=PHOTOREC_MAX_FILE_SIZE,
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.recover=1,
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2008-02-27 20:35:42 +01:00
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.enable_by_default=1,
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2007-10-29 22:38:52 +01:00
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.register_header_check=®ister_header_check_gif
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};
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static int header_check_gif(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)
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{
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2014-07-26 16:09:36 +02:00
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uint64_t offset;
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offset=6; /* Header */
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offset+=7; /* Logical Screen Descriptor */
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if((buffer[10]>>7)&0x1)
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{
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/* Global Color Table */
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offset+=3<<((buffer[10]&7)+1);
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2007-10-29 22:38:52 +01:00
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}
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2014-08-13 08:30:40 +02:00
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if(offset < buffer_size && buffer[offset]!=0x21 && buffer[offset]!=0x2c)
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return 0;
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reset_file_recovery(file_recovery_new);
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file_recovery_new->extension=file_hint_gif.extension;
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file_recovery_new->min_filesize=42;
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if(file_recovery_new->blocksize < 2)
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return 1;
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file_recovery_new->file_check=&file_check_gif;
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2014-07-26 16:09:36 +02:00
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file_recovery_new->calculated_file_size=offset;
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file_recovery_new->data_check=&data_check_gif;
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return 1;
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2007-10-29 22:38:52 +01:00
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}
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static void file_check_gif(file_recovery_t *file_recovery)
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{
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const unsigned char gif_footer[2]= {0x00, 0x3b};
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2014-03-29 11:24:44 +01:00
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unsigned char buffer[2];
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2015-04-11 14:23:16 +02:00
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if(my_fseek(file_recovery->handle, file_recovery->calculated_file_size-2, SEEK_SET)<0 ||
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2014-03-29 11:24:44 +01:00
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fread(buffer, 2, 1, file_recovery->handle)!=1 ||
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memcmp(buffer, gif_footer, sizeof(gif_footer))!=0)
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{
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file_recovery->file_size=0;
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return;
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}
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file_recovery->file_size=file_recovery->calculated_file_size;
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2007-10-29 22:38:52 +01:00
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}
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2009-01-04 19:44:41 +01:00
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2013-12-14 21:36:24 +01:00
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static data_check_t data_check_gif(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
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2009-01-04 19:44:41 +01:00
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{
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while(file_recovery->calculated_file_size + buffer_size/2 >= file_recovery->file_size &&
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2014-03-11 21:44:31 +01:00
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file_recovery->calculated_file_size + 2 < file_recovery->file_size + buffer_size/2)
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2009-01-04 19:44:41 +01:00
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{
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const unsigned int i=file_recovery->calculated_file_size - file_recovery->file_size + buffer_size/2;
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2014-03-11 21:44:31 +01:00
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#ifdef DEBUG_GIF
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log_info("data_check_gif calculated_file_size=0x%llx: 0x%02x\n",
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(long long unsigned)file_recovery->calculated_file_size, buffer[i]);
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#endif
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2009-01-04 19:44:41 +01:00
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switch(buffer[i])
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{
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case 0x21:
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2009-01-22 19:06:11 +01:00
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/* Plain Text Extension 21 01 ... */
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/* Graphic Control Extension 21 f9 04 XX XX XX XX 00 */
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/* Comment Extension 21 fe ... */
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/* Application Extension 21 ff */
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file_recovery->calculated_file_size+=2;
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return data_check_gif2(buffer, buffer_size, file_recovery);
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2009-01-04 19:44:41 +01:00
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case 0x2c:
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2014-03-11 21:44:31 +01:00
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if(file_recovery->calculated_file_size + 20 < file_recovery->file_size + buffer_size/2)
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2009-01-04 19:44:41 +01:00
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{
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2014-03-11 21:44:31 +01:00
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unsigned int j=10+1;
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/* 1 Image Descriptor id=0x2c
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* 4: NW corner
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* 4: width, heigth,
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* 1: is a local color table present ? */
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if(((buffer[i+9]>>7)&0x1)>0)
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2009-01-04 19:44:41 +01:00
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{
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/* local color table */
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2014-03-11 21:44:31 +01:00
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j+=3<<((buffer[i+9]&7)+1);
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2009-01-04 19:44:41 +01:00
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}
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2014-03-11 21:44:31 +01:00
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file_recovery->calculated_file_size+=j;
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/* 1: Start of image - LZW minimum code size */
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2009-01-04 19:44:41 +01:00
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/* Table Based Image Data */
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2014-03-11 21:44:31 +01:00
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return data_check_gif2(buffer, buffer_size, file_recovery);
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2009-01-04 19:44:41 +01:00
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}
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2014-03-11 21:44:31 +01:00
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return DC_CONTINUE;
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2009-01-04 19:44:41 +01:00
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case 0x3b:
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/* Trailer */
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file_recovery->calculated_file_size++;
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2013-12-14 21:36:24 +01:00
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return DC_STOP;
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2009-01-04 19:44:41 +01:00
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default:
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2013-12-14 21:36:24 +01:00
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return DC_ERROR;
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2009-01-04 19:44:41 +01:00
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}
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}
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file_recovery->data_check=&data_check_gif;
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2013-12-14 21:36:24 +01:00
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return DC_CONTINUE;
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2009-01-04 19:44:41 +01:00
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}
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2013-12-14 21:36:24 +01:00
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static data_check_t data_check_gif2(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
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2009-01-04 19:44:41 +01:00
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{
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while(file_recovery->calculated_file_size + buffer_size/2 >= file_recovery->file_size &&
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file_recovery->calculated_file_size + 2 < file_recovery->file_size + buffer_size/2)
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{
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const unsigned int i=file_recovery->calculated_file_size - file_recovery->file_size + buffer_size/2;
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2014-03-11 21:44:31 +01:00
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#ifdef DEBUG_GIF
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log_info("data_check_gif2 calculated_file_size=0x%llx\n",
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(long long unsigned)file_recovery->calculated_file_size);
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#endif
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2009-01-04 19:44:41 +01:00
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file_recovery->calculated_file_size+=buffer[i]+1;
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if(buffer[i]==0)
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{
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return data_check_gif(buffer, buffer_size, file_recovery);
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}
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}
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file_recovery->data_check=&data_check_gif2;
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2013-12-14 21:36:24 +01:00
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return DC_CONTINUE;
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2009-01-04 19:44:41 +01:00
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}
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2014-07-26 16:09:36 +02:00
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static void register_header_check_gif(file_stat_t *file_stat)
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{
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static const unsigned char gif_header[6]= { 'G','I','F','8','7','a'};
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static const unsigned char gif_header2[6]= { 'G','I','F','8','9','a'};
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register_header_check(0, gif_header,sizeof(gif_header), &header_check_gif, file_stat);
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register_header_check(0, gif_header2,sizeof(gif_header2), &header_check_gif, file_stat);
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}
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