/*

    File: file_riff.c

    Copyright (C) 1998-2005,2007-2011 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_riff)
#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 "file_riff.h"
#ifdef DEBUG_RIFF
#include "log.h"
#endif

/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_riff(file_stat_t *file_stat);

const file_hint_t file_hint_riff= {
  .extension="riff",
  .description="RIFF audio/video: wav, cdr, avi",
  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
  .recover=1,
  .enable_by_default=1,
  .register_header_check=&register_header_check_riff
};

typedef struct {
  uint32_t dwFourCC;
  uint32_t dwSize;
//  char data[dwSize];   // contains headers or video/audio data
} riff_chunk_header;

typedef struct {
  uint32_t dwList;
  uint32_t dwSize;
  uint32_t dwFourCC;
//  char data[dwSize-4];
} riff_list_header_t;

#ifdef DEBUG_RIFF
static void log_riff_list(const uint64_t offset, const unsigned int depth, const riff_list_header_t *list_header)
{
  unsigned int i;
  log_info("0x%08lx - 0x%08lx ", offset, offset + 8 - 1 + le32(list_header->dwSize));
  for(i = 0; i < depth; i++)
    log_info(" ");
  log_info("%c%c%c%c %c%c%c%c 0x%x\n",
      le32(list_header->dwList),
      le32(list_header->dwList)>>8,
      le32(list_header->dwList)>>16,
      le32(list_header->dwList)>>24,
      le32(list_header->dwFourCC),
      le32(list_header->dwFourCC)>>8,
      le32(list_header->dwFourCC)>>16,
      le32(list_header->dwFourCC)>>24,
      le32(list_header->dwSize));
}

static void log_riff_chunk(const uint64_t offset, const unsigned int depth, const riff_list_header_t *list_header)
{
  unsigned int i;
  if(le32(list_header->dwSize)==0)
    return ;
  log_info("0x%08lx - 0x%08lx ", offset, offset + 8 - 1 + le32(list_header->dwSize));
  for(i = 0; i < depth; i++)
    log_info(" ");
  log_info("%c%c%c%c 0x%x\n",
      le32(list_header->dwList),
      le32(list_header->dwList)>>8,
      le32(list_header->dwList)>>16,
      le32(list_header->dwList)>>24,
      le32(list_header->dwSize));
}
#endif

/*@
  @ requires \valid(fr);
  @ requires valid_file_recovery(fr);
  @ requires \valid(fr->handle);
  @ requires \separated(fr, fr->handle, fr->extension, &errno, &Frama_C_entropy_source);
  @ requires end <= PHOTOREC_MAX_FILE_SIZE;
  @ decreases 5 - depth;
  @ ensures  valid_file_recovery(fr);
  @ ensures  \valid(fr->handle);
  @ assigns  *fr->handle, errno;
  @ assigns  fr->offset_error;
  @ assigns  Frama_C_entropy_source;
  @*/
static void check_riff_list(file_recovery_t *fr, const unsigned int depth, const uint64_t start, const uint64_t end)
{
  uint64_t file_size;
  if(depth>5)
    return;
  /*@
    @ loop invariant valid_file_recovery(fr);
    @ loop invariant \valid(fr->handle);
    @ loop assigns *fr->handle, errno;
    @ loop assigns fr->offset_error;
    @ loop assigns Frama_C_entropy_source;
    @ loop assigns file_size;
    @ loop variant end - file_size;
    @*/
  for(file_size=start; file_size < end;)
  {
    char buf[sizeof(riff_list_header_t)];
    uint64_t next_fs;
    const riff_list_header_t *list_header=(const riff_list_header_t *)&buf;
    if(my_fseek(fr->handle, file_size, SEEK_SET)<0)
    {
      fr->offset_error=file_size;
      return;
    }
    if (fread(buf, sizeof(buf), 1, fr->handle)!=1)
    {
      fr->offset_error=file_size;
      return;
    }
#if defined(__FRAMAC__)
    Frama_C_make_unknown(buf, sizeof(buf));
#endif
    /*@ assert \initialized((char *)list_header+ (0 .. sizeof(riff_list_header_t)-1)); */
    next_fs=file_size + (uint64_t)8 + le32(list_header->dwSize);
    /*@ assert next_fs > file_size; */
    if(next_fs > end)
    {
      fr->offset_error=file_size;
      return;
    }
    /*@ assert valid_file_recovery(fr); */
    if(memcmp(&list_header->dwList, "LIST", 4) == 0)
    {
#ifdef DEBUG_RIFF
      log_riff_list(file_size, depth, list_header);
#endif
      check_riff_list(fr, depth+1, file_size + sizeof(riff_list_header_t), next_fs);
    }
    else
    {
#ifdef DEBUG_RIFF
      /* It's a chunk */
      log_riff_chunk(file_size, depth, list_header);
#endif
    }
    /* align to word boundary */
#ifdef __FRAMAC__
    file_size = (next_fs & 1 == 0 ? next_fs : next_fs + 1);
#else
    file_size = (next_fs+1) & ~(uint64_t)1;
#endif
    /*@ assert file_size >= next_fs; */
  }
}

/*@
  @ requires fr->file_check == &file_check_avi;
  @ requires valid_file_check_param(fr);
  @ ensures  valid_file_check_result(fr);
  @ assigns *fr->handle, errno, fr->file_size;
  @ assigns fr->offset_error, fr->offset_ok;
  @ assigns Frama_C_entropy_source;
  @*/
static void file_check_avi(file_recovery_t *fr)
{
  fr->file_size = 0;
  fr->offset_error=0;
  fr->offset_ok=0;
  /*@
    @ loop assigns *fr->handle, errno, fr->file_size;
    @ loop assigns fr->offset_error, fr->offset_ok;
    @ loop assigns Frama_C_entropy_source;
    @ loop variant fr->calculated_file_size - fr->file_size;
    @*/
  while(fr->file_size < fr->calculated_file_size)
  {
    const uint64_t file_size=fr->file_size;
    uint64_t calculated_file_size;
    char buffer[sizeof(riff_list_header_t)];
    const riff_list_header_t *list_header=(const riff_list_header_t *)&buffer;
    if(my_fseek(fr->handle, fr->file_size, SEEK_SET)<0)
    {
      fr->file_size=0;
      return ;
    }
    if (fread(&buffer, sizeof(buffer), 1, fr->handle)!=1)
    {
      fr->file_size=0;
      return;
    }
#if defined(__FRAMAC__)
    Frama_C_make_unknown(&buffer, sizeof(buffer));
#endif
#ifdef DEBUG_RIFF
    log_riff_list(file_size, 0, list_header);
#endif
    if(memcmp(&list_header->dwList, "RIFF", 4) != 0)
    {
      fr->offset_error=fr->file_size;
      return;
    }
    calculated_file_size=file_size + 8 + le32(list_header->dwSize);
    /*@ assert calculated_file_size > file_size; */
    /*@ assert calculated_file_size > fr->file_size; */
    if(calculated_file_size > PHOTOREC_MAX_FILE_SIZE)
    {
      fr->file_size=0;
      return;
    }
    /*@ assert calculated_file_size <= PHOTOREC_MAX_FILE_SIZE; */
    check_riff_list(fr, 1, file_size + sizeof(riff_list_header_t), calculated_file_size);
    if(fr->offset_error > 0)
    {
      fr->file_size=0;
      return;
    }
    fr->file_size=calculated_file_size;
  }
}

/*@
  @ requires file_recovery->data_check==&data_check_avi;
  @ requires valid_data_check_param(buffer, buffer_size, file_recovery);
  @ ensures  valid_data_check_result(\result, file_recovery);
  @ assigns file_recovery->calculated_file_size;
  @*/
static data_check_t data_check_avi(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;
    @ loop variant file_recovery->file_size + buffer_size/2 - (file_recovery->calculated_file_size + 12);
    @*/
  while(file_recovery->calculated_file_size + buffer_size/2  >= file_recovery->file_size &&
      file_recovery->calculated_file_size + 12 <= 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 - 12; */
    const riff_chunk_header *chunk_header=(const riff_chunk_header*)&buffer[i];
    if(memcmp(&buffer[i], "RIFF", 4)==0 && memcmp(&buffer[i+8], "AVIX", 4)==0)
      file_recovery->calculated_file_size += (uint64_t)8 + le32(chunk_header->dwSize);
    else
      return DC_STOP;
  }
  return DC_CONTINUE;
}

data_check_t data_check_avi_stream(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;
    @ loop variant file_recovery->file_size + buffer_size/2 - (file_recovery->calculated_file_size + 8);
    @ */
  while(file_recovery->calculated_file_size + buffer_size/2  >= file_recovery->file_size &&
      file_recovery->calculated_file_size + 8 <= 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 - 8; */
    const riff_chunk_header *chunk_header=(const riff_chunk_header*)&buffer[i];
    if(buffer[i+2]!='d' || buffer[i+3]!='b')	/* Video Data Binary ?*/
    {
#ifdef DEBUG_RIFF
      log_info("data_check_avi_stream stop\n");
#endif
      return DC_STOP;
    }
    file_recovery->calculated_file_size += (uint64_t)8 + le32(chunk_header->dwSize);
#ifdef DEBUG_RIFF
    log_info("data_check_avi_stream %llu\n", (long long unsigned)file_recovery->calculated_file_size);
#endif
  }
  return DC_CONTINUE;
}

/*@
  @ requires buffer_size >= 12;
  @ requires separation: \separated(&file_hint_riff, buffer+(..), file_recovery, file_recovery_new);
  @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
  @ ensures  valid_header_check_result(\result, file_recovery_new);
  @ assigns  *file_recovery_new;
  @*/
static int header_check_riff(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)
{
  uint64_t size;
  if(!( buffer[8]>='A' && buffer[8]<='Z' &&
	buffer[9]>='A' && buffer[9]<='Z' &&
	buffer[10]>='A' && buffer[10]<='Z' &&
	((buffer[11]>='A' && buffer[11]<='Z') || buffer[11]==' ' ||
	 (buffer[11]>='0' && buffer[11]<='9'))))
    return 0;
  if(memcmp(&buffer[8],"NUND",4)==0)
  {
    /* Cubase Project File */
    reset_file_recovery(file_recovery_new);
    file_recovery_new->extension="cpr";
    file_recovery_new->file_check=&file_check_size;
    file_recovery_new->data_check=&data_check_size;
    file_recovery_new->calculated_file_size=(((uint64_t)buffer[4])<<24) +
      (((uint64_t)buffer[5])<<16) + (((uint64_t)buffer[6])<<8) +
      (uint64_t)buffer[7] + 12;
    return 1;
  }
  size=(uint64_t)buffer[4]+(((uint64_t)buffer[5])<<8)+(((uint64_t)buffer[6])<<16)+(((uint64_t)buffer[7])<<24);

  /* Windows Animated Cursor */
  if(memcmp(&buffer[8],"ACON",4)==0)
  {
    if(size < 12)
      return 0;
    reset_file_recovery(file_recovery_new);
    file_recovery_new->file_check=&file_check_size;
    file_recovery_new->data_check=&data_check_size;
    file_recovery_new->calculated_file_size=size;
    file_recovery_new->extension="ani";
    return 1;
  }
  size+=8;
  if(memcmp(&buffer[8],"AVI ",4)==0)
  {
    const riff_list_header_t list_movi={
      .dwList=be32(0x4c495354),	/* LIST */
      .dwSize=le32(4),
      .dwFourCC=be32(0x6d6f7669)	/* movi */
    };
    reset_file_recovery(file_recovery_new);
    file_recovery_new->extension="avi";
    /* Is it a raw avi stream with Data Binary chunks ? */
    if(size >= sizeof(list_movi) && size <= buffer_size - 4 &&
	memcmp(&buffer[size - sizeof(list_movi)], &list_movi, sizeof(list_movi)) ==0 &&
	buffer[size+2]=='d' &&
	buffer[size+3]=='b')
    {
      if(file_recovery_new->blocksize < 8)
	return 1;
      file_recovery_new->data_check=&data_check_avi_stream;
      file_recovery_new->file_check=&file_check_size_max;
    }
    else
    {
      if(file_recovery_new->blocksize < 12)
	return 1;
      file_recovery_new->data_check=&data_check_avi;
      file_recovery_new->file_check=&file_check_avi;
    }
    file_recovery_new->calculated_file_size=size;
    return 1;
  }
  if(size < 12)
    return 0;
  reset_file_recovery(file_recovery_new);
  file_recovery_new->calculated_file_size=size;
  file_recovery_new->file_check=&file_check_size;
  file_recovery_new->data_check=&data_check_size;
  if(memcmp(&buffer[8],"CDDA",4)==0)
    file_recovery_new->extension="cda";
  else if(memcmp(&buffer[8],"CDR",3)==0 || memcmp(&buffer[8],"cdr6",4)==0)
    file_recovery_new->extension="cdr";
  else if(memcmp(&buffer[8],"RMP3",4)==0 || memcmp(&buffer[8],"WAVE",4)==0)
    file_recovery_new->extension="wav";
  /* MIDI sound file */
  else if(memcmp(&buffer[8],"RMID",4)==0)
    file_recovery_new->extension="mid";
  /* MIDI Instruments Definition File */
  else if(memcmp(&buffer[8],"IDF LIST",8)==0)
    file_recovery_new->extension="idf";
  /* Autogen http://www.fsdeveloper.com/wiki/index.php?title=AGN_%28FSX%29 */
  else if(memcmp(&buffer[8],"AGNX",4)==0)
    file_recovery_new->extension="agn";
  /* http://www.fsdeveloper.com/wiki/index.php?title=MDL_file_format_%28FSX%29 */
  else if(memcmp(&buffer[8],"MDLX",4)==0)
    file_recovery_new->extension="mdl";
  /* RFC3625  The QCP File Format and Media Types for Speech Data */
  else if(memcmp(&buffer[8],"QLCM",4)==0)
    file_recovery_new->extension="qcp";
  /* https://en.wikipedia.org/wiki/WebP */
  else if(memcmp(&buffer[8],"WEBP",4)==0)
    file_recovery_new->extension="webp";
  else
    file_recovery_new->extension="avi";
  return 1;
}

/*@
  @ requires buffer_size >= 12;
  @ requires separation: \separated(&file_hint_riff, buffer+(..), file_recovery, file_recovery_new);
  @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
  @ ensures  valid_header_check_result(\result, file_recovery_new);
  @ assigns  *file_recovery_new;
  @*/
static int header_check_rifx(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)
{
  if(memcmp(&buffer[8],"Egg!",4)==0)
  {
    /* After Effects */
    reset_file_recovery(file_recovery_new);
    file_recovery_new->file_check=&file_check_size_min;
    file_recovery_new->calculated_file_size=(uint64_t)buffer[7]+(((uint64_t)buffer[6])<<8)+(((uint64_t)buffer[5])<<16)+(((uint64_t)buffer[4])<<24)+8;
    file_recovery_new->extension="aep";
    return 1;
  }
  return 0;
}

static void register_header_check_riff(file_stat_t *file_stat)
{
  register_header_check(0, "RIFF", 4, &header_check_riff, file_stat);
  register_header_check(0, "RIFX", 4, &header_check_rifx, file_stat);
}
#endif